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Stoddart PR, Begeng JM, Tong W, Ibbotson MR, Kameneva T. Nanoparticle-based optical interfaces for retinal neuromodulation: a review. Front Cell Neurosci 2024; 18:1360870. [PMID: 38572073 PMCID: PMC10987880 DOI: 10.3389/fncel.2024.1360870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Accepted: 03/04/2024] [Indexed: 04/05/2024] Open
Abstract
Degeneration of photoreceptors in the retina is a leading cause of blindness, but commonly leaves the retinal ganglion cells (RGCs) and/or bipolar cells extant. Consequently, these cells are an attractive target for the invasive electrical implants colloquially known as "bionic eyes." However, after more than two decades of concerted effort, interfaces based on conventional electrical stimulation approaches have delivered limited efficacy, primarily due to the current spread in retinal tissue, which precludes high-acuity vision. The ideal prosthetic solution would be less invasive, provide single-cell resolution and an ability to differentiate between different cell types. Nanoparticle-mediated approaches can address some of these requirements, with particular attention being directed at light-sensitive nanoparticles that can be accessed via the intrinsic optics of the eye. Here we survey the available known nanoparticle-based optical transduction mechanisms that can be exploited for neuromodulation. We review the rapid progress in the field, together with outstanding challenges that must be addressed to translate these techniques to clinical practice. In particular, successful translation will likely require efficient delivery of nanoparticles to stable and precisely defined locations in the retinal tissues. Therefore, we also emphasize the current literature relating to the pharmacokinetics of nanoparticles in the eye. While considerable challenges remain to be overcome, progress to date shows great potential for nanoparticle-based interfaces to revolutionize the field of visual prostheses.
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Affiliation(s)
- Paul R. Stoddart
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC, Australia
| | - James M. Begeng
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC, Australia
- Department of Biomedical Engineering, Faculty of Engineering & Information Technology, The University of Melbourne, Melbourne, VIC, Australia
| | - Wei Tong
- Department of Biomedical Engineering, Faculty of Engineering & Information Technology, The University of Melbourne, Melbourne, VIC, Australia
- School of Physics, The University of Melbourne, Melbourne, VIC, Australia
| | - Michael R. Ibbotson
- Department of Biomedical Engineering, Faculty of Engineering & Information Technology, The University of Melbourne, Melbourne, VIC, Australia
| | - Tatiana Kameneva
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC, Australia
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2
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Mu H, Smith D, Ng SH, Anand V, Le NHA, Dharmavarapu R, Khajehsaeidimahabadi Z, Richardson RT, Ruther P, Stoddart PR, Gricius H, Baravykas T, Gailevičius D, Seniutinas G, Katkus T, Juodkazis S. Fraxicon for Optical Applications with Aperture ∼1 mm: Characterisation Study. Nanomaterials (Basel) 2024; 14:287. [PMID: 38334558 PMCID: PMC10856946 DOI: 10.3390/nano14030287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 12/19/2023] [Accepted: 01/22/2024] [Indexed: 02/10/2024]
Abstract
Emerging applications of optical technologies are driving the development of miniaturised light sources, which in turn require the fabrication of matching micro-optical elements with sub-1 mm cross-sections and high optical quality. This is particularly challenging for spatially constrained biomedical applications where reduced dimensionality is required, such as endoscopy, optogenetics, or optical implants. Planarisation of a lens by the Fresnel lens approach was adapted for a conical lens (axicon) and was made by direct femtosecond 780 nm/100 fs laser writing in the SZ2080™ polymer with a photo-initiator. Optical characterisation of the positive and negative fraxicons is presented. Numerical modelling of fraxicon optical performance under illumination by incoherent and spatially extended light sources is compared with the ideal case of plane-wave illumination. Considering the potential for rapid replication in soft polymers and resists, this approach holds great promise for the most demanding technological applications.
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Affiliation(s)
- Haoran Mu
- Optical Sciences Centre, ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (H.M.); (D.S.); (N.H.A.L.); (R.D.); (Z.K.); (P.R.S.); (G.S.); (T.K.); (S.J.)
| | - Daniel Smith
- Optical Sciences Centre, ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (H.M.); (D.S.); (N.H.A.L.); (R.D.); (Z.K.); (P.R.S.); (G.S.); (T.K.); (S.J.)
| | - Soon Hock Ng
- Optical Sciences Centre, ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (H.M.); (D.S.); (N.H.A.L.); (R.D.); (Z.K.); (P.R.S.); (G.S.); (T.K.); (S.J.)
- Melbourne Centre for Nanofabrication, Australian National Fabrication Facility, Clayton, VIC 3168, Australia
| | - Vijayakumar Anand
- Optical Sciences Centre, ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (H.M.); (D.S.); (N.H.A.L.); (R.D.); (Z.K.); (P.R.S.); (G.S.); (T.K.); (S.J.)
- Institute of Physics, University of Tartu, W. Ostwaldi 1, 50411 Tartu, Estonia
| | - Nguyen Hoai An Le
- Optical Sciences Centre, ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (H.M.); (D.S.); (N.H.A.L.); (R.D.); (Z.K.); (P.R.S.); (G.S.); (T.K.); (S.J.)
| | - Raghu Dharmavarapu
- Optical Sciences Centre, ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (H.M.); (D.S.); (N.H.A.L.); (R.D.); (Z.K.); (P.R.S.); (G.S.); (T.K.); (S.J.)
| | - Zahra Khajehsaeidimahabadi
- Optical Sciences Centre, ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (H.M.); (D.S.); (N.H.A.L.); (R.D.); (Z.K.); (P.R.S.); (G.S.); (T.K.); (S.J.)
| | - Rachael T. Richardson
- Bionics Institute, East Melbourne, VIC 3002, Australia;
- Medical Bionics Department, University of Melbourne, Fitzroy, VIC 3065, Australia
| | - Patrick Ruther
- Department of Microsystems Engineering (IMTEK), University of Freiburg, 79110 Freiburg im Breisgau, Germany;
- BrainLinks-BrainTools Center, University of Freiburg, 79110 Freiburg im Breisgau, Germany
| | - Paul R. Stoddart
- Optical Sciences Centre, ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (H.M.); (D.S.); (N.H.A.L.); (R.D.); (Z.K.); (P.R.S.); (G.S.); (T.K.); (S.J.)
| | - Henrikas Gricius
- Laser Research Center, Physics Faculty, Vilnius University, Sauletekio Ave. 10, 10223 Vilnius, Lithuania; (H.G.); (D.G.)
| | | | - Darius Gailevičius
- Laser Research Center, Physics Faculty, Vilnius University, Sauletekio Ave. 10, 10223 Vilnius, Lithuania; (H.G.); (D.G.)
| | - Gediminas Seniutinas
- Optical Sciences Centre, ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (H.M.); (D.S.); (N.H.A.L.); (R.D.); (Z.K.); (P.R.S.); (G.S.); (T.K.); (S.J.)
- Melbourne Centre for Nanofabrication, Australian National Fabrication Facility, Clayton, VIC 3168, Australia
| | - Tomas Katkus
- Optical Sciences Centre, ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (H.M.); (D.S.); (N.H.A.L.); (R.D.); (Z.K.); (P.R.S.); (G.S.); (T.K.); (S.J.)
| | - Saulius Juodkazis
- Optical Sciences Centre, ARC Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (H.M.); (D.S.); (N.H.A.L.); (R.D.); (Z.K.); (P.R.S.); (G.S.); (T.K.); (S.J.)
- Laser Research Center, Physics Faculty, Vilnius University, Sauletekio Ave. 10, 10223 Vilnius, Lithuania; (H.G.); (D.G.)
- WRH Program International Research Frontiers Initiative (IRFI) Tokyo Institute of Technology, Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
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3
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Han M, Silva SM, Russo MJ, Desroches PE, Lei W, Quigley AF, Kapsa RMI, Moulton SE, Stoddart PR, Greene GW. Lubricin (PRG-4) anti-fouling coating for surface-enhanced Raman spectroscopy biosensing: towards a hierarchical separation system for analysis of biofluids. Analyst 2023; 149:63-75. [PMID: 37933547 DOI: 10.1039/d3an00910f] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
Surface-enhanced Raman Spectroscopy (SERS) is a powerful optical sensing technique that amplifies the signal generated by Raman scattering by many orders of magnitude. Although the extreme sensitivity of SERS enables an extremely low limit of detection, even down to single molecule levels, it is also a primary limitation of the technique due to its tendency to equally amplify 'noise' generated by non-specifically adsorbed molecules at (or near) SERS-active interfaces. Eliminating interference noise is thus critically important to SERS biosensing and typically involves onerous extraction/purification/washing procedures and/or heavy dilution of biofluid samples. Consequently, direct analysis within biofluid samples or in vivo environments is practically impossible. In this study, an anti-fouling coating of recombinant human Lubricin (LUB) was self-assembled onto AuNP-modified glass slides via a simple drop-casting method. A series of Raman spectra were collected using rhodamine 6G (R6G) as a model analyte, which was spiked into NaCl solution or unprocessed whole blood. Likewise, we demonstrate the same sensing system for the quantitative detection of L-cysteine spiked in undiluted milk. It was demonstrated for the first time that LUB coating can mitigate the deleterious effect of fouling in a SERS sensor without compromising the detection of a target analyte, even in a highly fouling, complex medium like whole blood or milk. This feat is achieved through a molecular sieving property of LUB that separates small analytes from large fouling species directly at the sensing interface resulting in SERS spectra with low background (i.e., noise) levels and excellent analyte spectral fidelity. These findings indicate the great potential for using LUB coatings together with an analyte-selective layer to form a hierarchical separation system for SERS sensing of relevant analytes directly in complex biological media, aquaculture, food matrix or environmental samples.
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Affiliation(s)
- Mingyu Han
- Institute for Frontier Materials, Deakin University, Waurn Ponds, Victoria 3216, Australia.
- The Aikenhead Centre for Medical Discovery, St Vincent's Hospital Melbourne, Fitzroy, Victoria 3065, Australia
- Commonwealth Scientific and Industrial Research Organization (CSIRO), Agriculture and Food, 671 Sneydes Road, Werribee, Victoria, 3030, Australia
| | - Saimon M Silva
- ARC Centre of Excellence for Electromaterials Science, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
- The Aikenhead Centre for Medical Discovery, St Vincent's Hospital Melbourne, Fitzroy, Victoria 3065, Australia
- Iverson Health Innovation Research Institute, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
| | - Matthew J Russo
- Institute for Frontier Materials, Deakin University, Waurn Ponds, Victoria 3216, Australia.
| | - Pauline E Desroches
- Institute for Frontier Materials, Deakin University, Waurn Ponds, Victoria 3216, Australia.
| | - Weiwei Lei
- Institute for Frontier Materials, Deakin University, Waurn Ponds, Victoria 3216, Australia.
| | - Anita F Quigley
- The Aikenhead Centre for Medical Discovery, St Vincent's Hospital Melbourne, Fitzroy, Victoria 3065, Australia
- School of Electrical and Biomedical Engineering, RMIT University, Melbourne, Victoria 3001, Australia
| | - Robert M I Kapsa
- The Aikenhead Centre for Medical Discovery, St Vincent's Hospital Melbourne, Fitzroy, Victoria 3065, Australia
- School of Electrical and Biomedical Engineering, RMIT University, Melbourne, Victoria 3001, Australia
| | - Simon E Moulton
- ARC Centre of Excellence for Electromaterials Science, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
- The Aikenhead Centre for Medical Discovery, St Vincent's Hospital Melbourne, Fitzroy, Victoria 3065, Australia
- Iverson Health Innovation Research Institute, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
| | - Paul R Stoddart
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia.
| | - George W Greene
- Institute for Frontier Materials, Deakin University, Waurn Ponds, Victoria 3216, Australia.
- ARC Centre of Excellence for Electromaterials Science, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
- The Aikenhead Centre for Medical Discovery, St Vincent's Hospital Melbourne, Fitzroy, Victoria 3065, Australia
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4
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Nascimento ATD, Mendes AX, Begeng JM, Duchi S, Stoddart PR, Quigley AF, Kapsa RMI, Ibbotson MR, Silva SM, Moulton SE. A tissue-engineered neural interface with photothermal functionality. Biomater Sci 2023. [PMID: 37194340 DOI: 10.1039/d3bm00139c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Neural interfaces are well-established as a tool to understand the behaviour of the nervous system via recording and stimulation of living neurons, as well as serving as neural prostheses. Conventional neural interfaces based on metals and carbon-based materials are generally optimised for high conductivity; however, a mechanical mismatch between the interface and the neural environment can significantly reduce long-term neuromodulation efficacy by causing an inflammatory response. This paper presents a soft composite material made of gelatin methacryloyl (GelMA) containing graphene oxide (GO) conjugated with gold nanorods (AuNRs). The soft hydrogel presents stiffness within the neural environment range of modulus below 5 kPa, while the AuNRs, when exposed to light in the near infrared range, provide a photothermal response that can be used to improve the spatial and temporal precision of neuromodulation. These favourable properties can be maintained at safer optical power levels when combined with electrical stimulation. In this paper we provide mechanical and biological characterization of the optical activity of the GO-AuNR composite hydrogel. The optical functionality of the material has been evaluated via photothermal stimulation of explanted rat retinal tissue. The outcomes achieved with this study encourage further investigation into optical and electrical costimulation parameters for a range of biomedical applications.
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Affiliation(s)
- Adriana Teixeira do Nascimento
- ARC Centre of Excellence for Electromaterials Science, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Melbourne, Victoria 3122, Australia
- The Aikenhead Centre for Medical Discovery, St Vincent's Hospital Melbourne, Melbourne, Victoria 3065, Australia
| | - Alexandre Xavier Mendes
- ARC Centre of Excellence for Electromaterials Science, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Melbourne, Victoria 3122, Australia
- The Aikenhead Centre for Medical Discovery, St Vincent's Hospital Melbourne, Melbourne, Victoria 3065, Australia
| | - James M Begeng
- ARC Centre of Excellence for Electromaterials Science, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Melbourne, Victoria 3122, Australia
- National Vision Research Institute, The Australian College of Optometry, Carlton, VIC 3058, Australia
| | - Serena Duchi
- The Aikenhead Centre for Medical Discovery, St Vincent's Hospital Melbourne, Melbourne, Victoria 3065, Australia
- Department of Surgery, University of Melbourne, St Vincent's Hospital, Melbourne, Victoria 3065, Australia
| | - Paul R Stoddart
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
| | - Anita F Quigley
- The Aikenhead Centre for Medical Discovery, St Vincent's Hospital Melbourne, Melbourne, Victoria 3065, Australia
- School of Electrical and Biomedical Engineering, RMIT University, Melbourne, Victoria 3001, Australia
- Department of Medicine, University of Melbourne, St Vincent's Hospital Melbourne, Victoria 3065, Australia
| | - Robert M I Kapsa
- The Aikenhead Centre for Medical Discovery, St Vincent's Hospital Melbourne, Melbourne, Victoria 3065, Australia
- School of Electrical and Biomedical Engineering, RMIT University, Melbourne, Victoria 3001, Australia
- Department of Medicine, University of Melbourne, St Vincent's Hospital Melbourne, Victoria 3065, Australia
| | - Michael R Ibbotson
- National Vision Research Institute, The Australian College of Optometry, Carlton, VIC 3058, Australia
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Saimon M Silva
- ARC Centre of Excellence for Electromaterials Science, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Melbourne, Victoria 3122, Australia
- The Aikenhead Centre for Medical Discovery, St Vincent's Hospital Melbourne, Melbourne, Victoria 3065, Australia
- Iverson Health Innovation Research Institute, Swinburne University of Technology, Melbourne, Victoria 3122, Australia.
| | - Simon E Moulton
- ARC Centre of Excellence for Electromaterials Science, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Melbourne, Victoria 3122, Australia
- The Aikenhead Centre for Medical Discovery, St Vincent's Hospital Melbourne, Melbourne, Victoria 3065, Australia
- Iverson Health Innovation Research Institute, Swinburne University of Technology, Melbourne, Victoria 3122, Australia.
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5
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Mu H, Smith D, Katkus T, Gailevičius D, Malinauskas M, Nishijima Y, Stoddart PR, Ruan D, Ryu M, Morikawa J, Vasiliev T, Lozovski V, Moraru D, Ng SH, Juodkazis S. Polarisation Control in Arrays of Microlenses and Gratings: Performance in Visible-IR Spectral Ranges. Micromachines (Basel) 2023; 14:798. [PMID: 37421030 DOI: 10.3390/mi14040798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 03/29/2023] [Accepted: 03/30/2023] [Indexed: 07/09/2023]
Abstract
Microlens arrays (MLAs) which are increasingly popular micro-optical elements in compact integrated optical systems were fabricated using a femtosecond direct laser write (fs-DLW) technique in the low-shrinkage SZ2080TM photoresist. High-fidelity definition of 3D surfaces on IR transparent CaF2 substrates allowed to achieve ∼50% transmittance in the chemical fingerprinting spectral region 2-5 μm wavelengths since MLAs were only ∼10 μm high corresponding to the numerical aperture of 0.3 (the lens height is comparable with the IR wavelength). To combine diffractive and refractive capabilities in miniaturised optical setup, a graphene oxide (GO) grating acting as a linear polariser was also fabricated by fs-DLW by ablation of a 1 μm-thick GO thin film. Such an ultra-thin GO polariser can be integrated with the fabricated MLA to add dispersion control at the focal plane. Pairs of MLAs and GO polarisers were characterised throughout the visible-IR spectral window and numerical modelling was used to simulate their performance. A good match between the experimental results of MLA focusing and simulations was achieved.
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Affiliation(s)
- Haoran Mu
- Optical Sciences Centre, Australian Research Council (ARC) Industrial Transformation Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Daniel Smith
- Optical Sciences Centre, Australian Research Council (ARC) Industrial Transformation Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Tomas Katkus
- Optical Sciences Centre, Australian Research Council (ARC) Industrial Transformation Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Darius Gailevičius
- Laser Research Center, Physics Faculty, Vilnius University, Sauletekio Ave. 10, LT-10222 Vilnius, Lithuania
| | - Mangirdas Malinauskas
- Laser Research Center, Physics Faculty, Vilnius University, Sauletekio Ave. 10, LT-10222 Vilnius, Lithuania
| | - Yoshiaki Nishijima
- Department of Electrical and Computer Engineering, Graduate School of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
- Institute of Advanced Sciences, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
| | - Paul R Stoddart
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Dong Ruan
- School of Engineering, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Meguya Ryu
- National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 3, 1-1-1 Umezono, Tsukuba 305-8563, Japan
| | - Junko Morikawa
- WRH Program International Research Frontiers Initiative (IRFI), Tokyo Institute of Technology, Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
- CREST-JST, School of Materials and Chemical Technology, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Taras Vasiliev
- Institute of High Technologies, Taras Shevchenko National University of Kyiv, Volodymyrska Str. 60, 01602 Kyiv, Ukraine
| | - Valeri Lozovski
- Institute of High Technologies, Taras Shevchenko National University of Kyiv, Volodymyrska Str. 60, 01602 Kyiv, Ukraine
| | - Daniel Moraru
- Optical Sciences Centre, Australian Research Council (ARC) Industrial Transformation Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia
- Research Institute of Electronics, Shizuoka University, Johoku 3-5-1, Hamamatsu 432-8011, Japan
| | - Soon Hock Ng
- Optical Sciences Centre, Australian Research Council (ARC) Industrial Transformation Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia
- Melbourne Centre for Nanofabrication, 151 Wellington Road, Clayton, VIC 3168, Australia
| | - Saulius Juodkazis
- Optical Sciences Centre, Australian Research Council (ARC) Industrial Transformation Training Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, VIC 3122, Australia
- WRH Program International Research Frontiers Initiative (IRFI), Tokyo Institute of Technology, Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
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6
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Begeng JM, Tong W, Rosal BD, Ibbotson M, Kameneva T, Stoddart PR. Activity of Retinal Neurons Can Be Modulated by Tunable Near-Infrared Nanoparticle Sensors. ACS Nano 2023; 17:2079-2088. [PMID: 36724043 DOI: 10.1021/acsnano.2c07663] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The vision of patients rendered blind by photoreceptor degeneration can be partially restored by exogenous stimulation of surviving retinal ganglion cells (RGCs). Whereas conventional electrical stimulation techniques have failed to produce naturalistic visual percepts, nanoparticle-based optical sensors have recently received increasing attention as a means to artificially stimulate the RGCs. In particular, nanoparticle-enhanced infrared neural modulation (NINM) is a plasmonically mediated photothermal neuromodulation technique that has a demonstrated capacity for both stimulation and inhibition, which is essential for the differential modulation of ON-type and OFF-type RGCs. Gold nanorods provide tunable absorption through the near-infrared wavelength window, which reduces interference with any residual vision. Therefore, NINM may be uniquely well-suited to retinal prosthesis applications but, to our knowledge, has not previously been demonstrated in RGCs. In the present study, NINM laser pulses of 100 μs, 500 μs and 200 ms were applied to RGCs in explanted rat retinae, with single-cell responses recorded via patch-clamping. The shorter laser pulses evoked robust RGC stimulation by capacitive current generation, while the long laser pulses are capable of inhibiting spontaneous action potentials by thermal block. Importantly, an implicit bias toward OFF-type inhibition is observed, which may have important implications for the feasibility of future high-acuity retinal prosthesis design based on nanoparticle sensors.
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Affiliation(s)
- James M Begeng
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, John Street, Hawthorn, VictoriaAustralia3122
- The Australian College of Optometry, The National Vision Research Institute, 386 Cardigan Street, Carlton, VictoriaAustralia3053
| | - Wei Tong
- The Australian College of Optometry, The National Vision Research Institute, 386 Cardigan Street, Carlton, VictoriaAustralia3053
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Melbourne, Victoria, Australia3010
- School of Physics, The University of Melbourne, Parkville, Melbourne, Victoria, Australia3010
| | - Blanca Del Rosal
- School of Science, RMIT University, Melbourne, Victoria, Australia3000
| | - Michael Ibbotson
- The Australian College of Optometry, The National Vision Research Institute, 386 Cardigan Street, Carlton, VictoriaAustralia3053
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Melbourne, Victoria, Australia3010
| | - Tatiana Kameneva
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, John Street, Hawthorn, VictoriaAustralia3122
| | - Paul R Stoddart
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, John Street, Hawthorn, VictoriaAustralia3122
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7
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Fraysse KS, Meaney SP, Gates WP, Langley DP, Tabor RF, Stoddart PR, Greene GW. Frequency Dependent Silica Dissolution Rate Enhancement under Oscillating Pressure via an Electrochemical Pressure Solution-like, Surface Resonance Mechanism. J Am Chem Soc 2022; 144:3875-3891. [PMID: 35226480 DOI: 10.1021/jacs.1c11545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
From atomic force microscopy (AFM) experiments, we report a new phenomenon in which the dissolution rate of fused silica is enhanced by more than 5 orders of magnitude by simply pressing a second, dissimilar surface against it and oscillating the contact pressure at low kHz frequencies in deionized water. The silica dissolution rate enhancement was found to exhibit a strong dependence on the pressure oscillation frequency consistent with a resonance effect. This harmonic enhancement of the silica dissolution rate was only observed at asymmetric material interfaces (e.g., diamond on silica) with no evidence of dissolution rate enhancement observed at symmetric material interfaces (i.e., silica on silica) within the experimental time scales. The apparent requirement for interface dissimilarity, the results of analogous experiments performed in anhydrous dodecane, and the observation that the silica "dissolution pits" continue to grow in size under contact stresses well below the silica yield stress refute a mechanical deformation or chemo-mechanical origin to the observed phenomenon. Instead, the silica dissolution rate enhancement exhibits characteristics consistent with a previously described 'electrochemical pressure solution' mechanism, albeit, with greatly amplified kinetics. Using a framework of electrochemical pressure solution, an electrochemical model of mineral dissolution, and a recently proposed "surface resonance" theory, we present an electro-chemo-mechanical mechanism that explains how oscillating the contact pressure between dissimilar surfaces in water can amplify surface dissolution rates by many orders of magnitude. This reaction rate enhancement mechanism has implications not only for dissolution but also for potentially other reactions occurring at the solid-liquid interface, e.g. catalysis.
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Affiliation(s)
- Kilian Shani Fraysse
- Institute for Frontier Materials and ARC Centre of Excellence for Electromaterials Science, Deakin University, Waurn Ponds, 3216, Australia
| | - Shane P Meaney
- School of Chemistry, Monash University, Clayton, 3800, Australia
| | - Will P Gates
- Institute for Frontier Materials and ARC Centre of Excellence for Electromaterials Science, Deakin University, Waurn Ponds, 3216, Australia
| | - Daniel P Langley
- School of Science, Computing and Engineering Technology, Swinburne University of Technology, Hawthorn, 3122, Australia.,Biomedical Manufacturing, CSIRO Manufacturing, Clayton, 3168, Australia
| | - Rico F Tabor
- School of Chemistry, Monash University, Clayton, 3800, Australia
| | - Paul R Stoddart
- School of Science, Computing and Engineering Technology, Swinburne University of Technology, Hawthorn, 3122, Australia
| | - George W Greene
- Institute for Frontier Materials and ARC Centre of Excellence for Electromaterials Science, Deakin University, Waurn Ponds, 3216, Australia
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Vegi Y, Charnley M, Earl SK, Onofrillo C, del Rosal B, Chong CJ, Stoddart PR, Cole N, Choong PF, Moulton SE, Reynolds NP. Photothermal release and recovery of mesenchymal stem cells from substrates functionalized with gold nanorods. Acta Biomater 2021; 129:110-121. [PMID: 34010693 DOI: 10.1016/j.actbio.2021.05.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 04/21/2021] [Accepted: 05/06/2021] [Indexed: 12/19/2022]
Abstract
Mesenchymal stem cell therapies show great promise in regenerative medicine. However, to generate clinically relevant numbers of these stem cells, significant in vitro expansion of the cells is required before transplantation into the affected wound or defect. The current gold standard protocol for recovering in vitro cultured cells involves treatment with enzymes such as trypsin which can affect the cell phenotype and ability to interact with the environment. Alternative enzyme free methods of adherent cell recovery have been investigated, but none match the convenience and performance of enzymatic detachment. In this work we have developed a synthetically simple, low cost cell culture substrate functionalized with gold nanorods that can support cell proliferation and detachment. When these nanorods are irradiated with biocompatible low intensity near infrared radiation (785 nm, 560 mWcm-2) they generate localized surface plasmon resonance induced nanoscale heating effects which trigger detachment of adherent mesenchymal stem cells. Through simulations and thermometry experiments we show that this localized heating is concentrated at the cell-nanorod interface, and that the stem cells detached using this technique show either similar or improved multipotency, viability and ability to differentiate into clinically desirable osteo and adipocytes, compared to enzymatically harvested cells. This proof-of-principle work shows that photothermally mediated cell detachment is a promising method for recovering mesenchymal stem cells from in vitro culture substrates, and paves the way for further studies to scale up this process and facilitate its clinical translation. STATEMENT OF SIGNIFICANCE: New non-enzymatic methods of harvesting adherent cells without damaging or killing them are highly desirable in fields such as regenerative medicine. Here, we present a synthetically simple, non-toxic, infra-red induced method of harvesting mesenchymal stem cells from gold nanorod functionalized substrates. The detached cells retain their ability to differentiate into therapeutically valuable osteo and adipocytes. This work represents a significant improvement on similar cell harvesting studies due to: its simplicity; the use of clinically valuable stem cells as oppose to immortalized cell lines; and the extensive cellular characterization performed. Understanding, not just if cells live or die but how they proliferate and differentiate after photothermal detachment will be essential for the translation of this and similar techniques into commercial devices.
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9
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Affiliation(s)
- Rui Adão
- Department of Surgery and Physiology, Cardiovascular Research and Development Center-UnIC, Faculty of Medicine, University of Porto, Al. Prof. Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Paul R Stoddart
- Department of Telecommunications, Electrical, Robotics and Biomedical Engineering, Swinburne University of Technology, John Street, Hawthorn, Victoria 3122, Australia
| | - Karlheinz Peter
- Department of Atherothrombosis & Vascular Biology, Baker Heart & Diabetes Institute, 75 Commercial Rd, Melbourne, Victoria 3004, Australia.,Department of Medicine and Immunology, Monash University, 99 Commercial Rd, Melbourne, Victoria 3004, Australia.,Department of Cardiometabolic Health, Melbourne University, 30 Flemington Rd, Parkville, VIC 3052, Australia.,Department of Cardiology, Alfred Hospital, 55 Commercial Rd, Melbourne, Victoria 3004, Australia
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10
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Brown WGA, Needham K, Begeng JM, Thompson AC, Nayagam BA, Kameneva T, Stoddart PR. Response of primary auditory neurons to stimulation with infrared light in vitro. J Neural Eng 2021; 18:046003. [PMID: 33724234 DOI: 10.1088/1741-2552/abe7b8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Infrared light can be used to modulate the activity of neuronal cells through thermally-evoked capacitive currents and thermosensitive ion channel modulation. The infrared power threshold for action potentials has previously been found to be far lower in the in vivo cochlea when compared with other neuronal targets, implicating spiral ganglion neurons (SGNs) as a potential target for infrared auditory prostheses. However, conflicting experimental evidence suggests that this low threshold may arise from an intermediary mechanism other than direct SGN stimulation, potentially involving residual hair cell activity. APPROACH Patch-clamp recordings from cultured SGNs were used to explicitly quantify the capacitive and ion channel currents in an environment devoid of hair cells. Neurons were irradiated by a 1870 nm laser with pulse durations of 0.2-5.0 ms and powers up to 1.5 W. A Hodgkin-Huxley-type model was established by first characterising the voltage dependent currents, and then incorporating laser-evoked currents separated into temperature-dependent and temperature-gradient-dependent components. This model was found to accurately simulate neuronal responses and allowed the results to be extrapolated to stimulation parameter spaces not accessible during this study. MAIN RESULTS The previously-reported low in vivo SGN stimulation threshold was not observed, and only subthreshold depolarisation was achieved, even at high light exposures. Extrapolating these results with our Hodgkin-Huxley-type model predicts an action potential threshold which does not deviate significantly from other neuronal types. SIGNIFICANCE This suggests that the low-threshold response that is commonly reported in vivo may arise from an alternative mechanism, and calls into question the potential usefulness of the effect for auditory prostheses. The step-wise approach to modelling optically-evoked currents described here may prove useful for analysing a wider range of cell types where capacitive currents and conductance modulation are dominant.
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Affiliation(s)
- William G A Brown
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, John Street, Hawthorn VIC 3122, Australia
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11
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De Leon SE, Cleuren L, Oo ZY, Stoddart PR, McArthur SL. Extending In-Plane Impedance Measurements from 2D to 3D Cultures: Design Considerations. Bioengineering (Basel) 2021; 8:11. [PMID: 33450860 PMCID: PMC7828367 DOI: 10.3390/bioengineering8010011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/21/2020] [Accepted: 12/29/2020] [Indexed: 11/22/2022] Open
Abstract
Three-dimensional (3D) cell cultures have recently emerged as tools for biologically modelling the human body. As 3D models make their way into laboratories there is a need to develop characterisation techniques that are sensitive enough to monitor the cells in real time and without the need for chemical labels. Impedance spectroscopy has been shown to address both of these challenges, but there has been little research into the full impedance spectrum and how the different components of the system affect the impedance signal. Here we investigate the impedance of human fibroblast cells in 2D and 3D collagen gel cultures across a broad range of frequencies (10 Hz to 5 MHz) using a commercial well with in-plane electrodes. At low frequencies in both 2D and 3D models it was observed that protein adsorption influences the magnitude of the impedance for the cell-free samples. This effect was eliminated once cells were introduced to the systems. Cell proliferation could be monitored in 2D at intermediate frequencies (30 kHz). However, the in-plane electrodes were unable to detect any changes in the impedance at any frequency when the cells were cultured in the 3D collagen gel. The results suggest that in designing impedance measurement devices, both the nature and distribution of the cells within the 3D culture as well as the architecture of the electrodes are key variables.
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Affiliation(s)
- Sorel E. De Leon
- Bioengineering Research Group, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (S.E.D.L.); (Z.Y.O.); (P.R.S.)
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Clayton, VIC 3168, Australia
| | - Lana Cleuren
- PXL University College, Hasselt University, 3500 Hasselt, Belgium;
| | - Zay Yar Oo
- Bioengineering Research Group, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (S.E.D.L.); (Z.Y.O.); (P.R.S.)
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Clayton, VIC 3168, Australia
| | - Paul R. Stoddart
- Bioengineering Research Group, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (S.E.D.L.); (Z.Y.O.); (P.R.S.)
| | - Sally L. McArthur
- Bioengineering Research Group, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia; (S.E.D.L.); (Z.Y.O.); (P.R.S.)
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Clayton, VIC 3168, Australia
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12
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Anand V, Maksimovic J, Katkus T, Ng SH, Ulcinas O, Mikutis M, Baltrukonis J, Urbas A, Slekys G, Ogura H, Sagae D, Pikuz T, Somekawa T, Ozaki N, Vailionis A, Seniutinas G, Mizeikis V, Glazebrook K, Brodie J, Stoddart PR, Rapp L, Rode A, Gamaly E, Juodkazis S. All femtosecond optical pump and X-ray probe: holey-axicon for free electron lasers. J Phys Photonics 2020. [DOI: 10.1088/2515-7647/abd4ef] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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13
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Thompson AC, Wise AK, Hart WL, Needham K, Fallon JB, Gunewardene N, Stoddart PR, Richardson RT. Hybrid optogenetic and electrical stimulation for greater spatial resolution and temporal fidelity of cochlear activation. J Neural Eng 2020; 17:056046. [PMID: 33036009 DOI: 10.1088/1741-2552/abbff0] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Compared to electrical stimulation, optogenetic stimulation has the potential to improve the spatial precision of neural activation in neuroprostheses, but it requires intense light and has relatively poor temporal kinetics. We tested the effect of hybrid stimulation, which is the combination of subthreshold optical and electrical stimuli, on spectral and temporal fidelity in the cochlea by recording multiunit activity in the inferior colliculus of channelrhodopsin (H134R variant) transgenic mice. APPROACH Pulsed light or biphasic electrical pulses were delivered to cochlear spiral ganglion neurons of acutely deafened mice, either as individual stimuli or as hybrid stimuli for which the timing of the electrical pulse had a varied delay relative to the start of the optical pulse. Response thresholds, spread of activation and entrainment data were obtained from multi-unit recordings from the auditory midbrain. MAIN RESULTS Facilitation occurred when subthreshold electrical stimuli were applied at the end of, or up to 3.75 ms after subthreshold optical pulses. The spread of activation resulting from hybrid stimulation was significantly narrower than electrical-only and optical-only stimulation (p < 0.01), measured at equivalent suprathreshold levels of loudness that are relevant to cochlear implant users. Furthermore, temporal fidelity, measured as maximum following rates to 300 ms pulse trains bursts up to 240 Hz, was 2.4-fold greater than optical-only stimulation (p < 0.05). SIGNIFICANCE By significantly improving spectral resolution of electrical- and optical-only stimulation and the temporal fidelity of optical-only stimulation, hybrid stimulation has the potential to increase the number of perceptually independent stimulating channels in a cochlear implant.
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Zaguri D, Shaham-Niv S, Chakraborty P, Arnon Z, Makam P, Bera S, Rencus-Lazar S, Stoddart PR, Gazit E, Reynolds NP. Nanomechanical Properties and Phase Behavior of Phenylalanine Amyloid Ribbon Assemblies and Amorphous Self-Healing Hydrogels. ACS Appl Mater Interfaces 2020; 12:21992-22001. [PMID: 32307977 DOI: 10.1021/acsami.0c01574] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Phenylalanine was the minimalistic and first of numerous nonproteinaceous building blocks to be demonstrated to form amyloid-like fibrils. This unexpected organization of such a simple building block into canonical architecture, which was previously observed only with proteins and peptides, has numerous implications for medicine and supramolecular chemistry. However, the morphology of phenylalanine fibrils and their mechanical properties was never characterized in solutions. Here, using electron and atomic force microscopy, we analyze the morphological and mechanical properties of phenylalanine fibrils in both air and fluids. The fibrils demonstrate an exceptionally high Young's modulus (up to 30 GPa) and are found to be composed of intertwined protofilaments in a helical or twisted ribbon morphology. In addition, X-ray scattering experiments provide convincing evidence of an amyloidal cross-β-like secondary structure within the nanoassemblies. Furthermore, increasing the phenylalanine concentration results in the formation of highly homogenous, noncrystalline, self-healing hydrogels that display storage and loss moduli significantly higher than similar noncovalently cross-linked biomolecular nanofibrillar scaffolds. These remarkably stiff nanofibrillar hydrogels can be harnessed for various technological and biomedical applications, such as self-healing, printable, structural, load-bearing 3D scaffolds. The properties of this simple but quite remarkable hydrogel open a possibility to utilize it in the biomaterial industry.
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Affiliation(s)
- Dor Zaguri
- School of Molecular Cell Biology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Shira Shaham-Niv
- BLAVATNIK CENTER for Drug Discovery, Metabolite Medicine Division, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Priyadarshi Chakraborty
- School of Molecular Cell Biology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Zohar Arnon
- School of Molecular Cell Biology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Pandeeswar Makam
- School of Molecular Cell Biology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Santu Bera
- School of Molecular Cell Biology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Sigal Rencus-Lazar
- School of Molecular Cell Biology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Paul R Stoddart
- ARC Training Centre in Biodevices, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, Victoria 3122, Australia
| | - Ehud Gazit
- School of Molecular Cell Biology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
- BLAVATNIK CENTER for Drug Discovery, Metabolite Medicine Division, Tel Aviv University, Tel Aviv 6997801, Israel
- Department of Materials Science and Engineering, Iby and Aladar Fleischman Faculty of Engineering, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Nicholas P Reynolds
- ARC Training Centre in Biodevices, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, Victoria 3122, Australia
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3083, Australia
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15
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Yap JYY, Keatch C, Lambert E, Woods W, Stoddart PR, Kameneva T. Critical Review of Transcutaneous Vagus Nerve Stimulation: Challenges for Translation to Clinical Practice. Front Neurosci 2020; 14:284. [PMID: 32410932 PMCID: PMC7199464 DOI: 10.3389/fnins.2020.00284] [Citation(s) in RCA: 148] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 03/12/2020] [Indexed: 12/25/2022] Open
Abstract
Several studies have illustrated that transcutaneous vagus nerve stimulation (tVNS) can elicit therapeutic effects that are similar to those produced by its invasive counterpart, vagus nerve stimulation (VNS). VNS is an FDA-approved therapy for the treatment of both depression and epilepsy, but it is limited to the management of more severe, intervention-resistant cases as a second or third-line treatment option due to perioperative risks involved with device implantation. In contrast, tVNS is a non-invasive technique that involves the application of electrical currents through surface electrodes at select locations, most commonly targeting the auricular branch of the vagus nerve (ABVN) and the cervical branch of the vagus nerve in the neck. Although it has been shown that tVNS elicits hypo- and hyperactivation in various regions of the brain associated with anxiety and mood regulation, the mechanism of action and influence of stimulation parameters on clinical outcomes remains predominantly hypothetical. Suppositions are largely based on correlations between the neurobiology of the vagus nerve and its effects on neural activity. However, tVNS has also been investigated for several other disorders, including tinnitus, migraine and pain, by targeting the vagus nerve at sites in both the ear and the neck. As most of the described methods differ in the parameters and protocols applied, there is currently no firm evidence on the optimal location for tVNS or the stimulation parameters that provide the greatest therapeutic effects for a specific condition. This review presents the current status of tVNS with a focus on stimulation parameters, stimulation sites, and available devices. For tVNS to reach its full potential as a non-invasive and clinically relevant therapy, it is imperative that systematic studies be undertaken to reveal the mechanism of action and optimal stimulation modalities.
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Affiliation(s)
- Jonathan Y. Y. Yap
- ARC Training Centre in Biodevices, Swinburne University of Technology, Hawthorn, VIC, Australia
| | - Charlotte Keatch
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC, Australia
| | - Elisabeth Lambert
- School of Health Sciences, Swinburne University of Technology, Hawthorn, VIC, Australia
- Iverson Health Innovation Research Institute, Swinburne University of Technology, Hawthorn, VIC, Australia
| | - Will Woods
- School of Health Sciences, Swinburne University of Technology, Hawthorn, VIC, Australia
| | - Paul R. Stoddart
- ARC Training Centre in Biodevices, Swinburne University of Technology, Hawthorn, VIC, Australia
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC, Australia
| | - Tatiana Kameneva
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC, Australia
- Iverson Health Innovation Research Institute, Swinburne University of Technology, Hawthorn, VIC, Australia
- Department of Biomedical Engineering, The University of Melbourne, Parkville, VIC, Australia
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16
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Brown WGA, Needham K, Begeng JM, Thompson AC, Nayagam BA, Kameneva T, Stoddart PR. Thermal damage threshold of neurons during infrared stimulation. Biomed Opt Express 2020; 11:2224-2234. [PMID: 32341879 PMCID: PMC7173919 DOI: 10.1364/boe.383165] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 02/11/2020] [Accepted: 03/23/2020] [Indexed: 05/25/2023]
Abstract
In infrared neural stimulation (INS), laser-evoked thermal transients are used to generate small depolarising currents in neurons. The laser exposure poses a moderate risk of thermal damage to the target neuron. Indeed, exogenous methods of neural stimulation often place the target neurons under stressful non-physiological conditions, which can hinder ordinary neuronal function and hasten cell death. Therefore, quantifying the exposure-dependent probability of neuronal damage is essential for identifying safe operating limits of INS and other interventions for therapeutic and prosthetic use. Using patch-clamp recordings in isolated spiral ganglion neurons, we describe a method for determining the dose-dependent damage probabilities of individual neurons in response to both acute and cumulative infrared exposure parameters based on changes in injection current. The results identify a local thermal damage threshold at approximately 60 °C, which is in keeping with previous literature and supports the claim that damage during INS is a purely thermal phenomenon. In principle this method can be applied to any potentially injurious stimuli, allowing for the calculation of a wide range of dose-dependent neural damage probabilities. Unlike histological analyses, the technique is well-suited to quantifying gradual neuronal damage, and critical threshold behaviour is not required.
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Affiliation(s)
- William G. A. Brown
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, John Street, Hawthorn, VIC 3122, Australia
| | - Karina Needham
- Department of Surgery (Otolaryngology), University of Melbourne, Royal Victoria Eye & Ear Hospital, 32 Gisborne St, East Melbourne, VIC 3002, Australia
| | - James M. Begeng
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, John Street, Hawthorn, VIC 3122, Australia
| | | | - Bryony A. Nayagam
- Department of Audiology and Speech Pathology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Tatiana Kameneva
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, John Street, Hawthorn, VIC 3122, Australia
| | - Paul R. Stoddart
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, John Street, Hawthorn, VIC 3122, Australia
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17
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Hart WL, Richardson RT, Kameneva T, Thompson AC, Wise AK, Fallon JB, Stoddart PR, Needham K. Combined optogenetic and electrical stimulation of auditory neurons increases effective stimulation frequency-an in vitro study. J Neural Eng 2020; 17:016069. [PMID: 31923907 DOI: 10.1088/1741-2552/ab6a68] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
OBJECTIVE The performance of neuroprostheses, including cochlear and retinal implants, is currently constrained by the spatial resolution of electrical stimulation. Optogenetics has improved the spatial control of neurons in vivo but lacks the fast-temporal dynamics required for auditory and retinal signalling. The objective of this study is to demonstrate that combining optical and electrical stimulation in vitro could address some of the limitations associated with each of the stimulus modes when used independently. APPROACH The response of murine auditory neurons expressing ChR2-H134 to combined optical and electrical stimulation was characterised using whole cell patch clamp electrophysiology. MAIN RESULTS Optogenetic costimulation produces a three-fold increase in peak firing rate compared to optical stimulation alone and allows spikes to be evoked by combined subthreshold optical and electrical inputs. Subthreshold optical depolarisation also facilitated spiking in auditory neurons for periods of up to 30 ms without evidence of wide-scale Na+ inactivation. SIGNIFICANCE These findings may contribute to the development of spatially and temporally selective optogenetic-based neuroprosthetics and complement recent developments in 'fast opsins'.
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Affiliation(s)
- William L Hart
- ARC Training Centre in Biodevices, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Rachael T Richardson
- The Bionics Institute, East Melbourne, VIC 3002, Australia
- Department of Surgery (Otolaryngology), University of Melbourne, The Royal Victorian Eye and Ear Hospital, East Melbourne, VIC 3002, Australia
- Medical Bionics Department, University of Melbourne, East Melbourne, VIC 3002, Australia
| | - Tatiana Kameneva
- Swinburne University of Technology, Hawthorn VIC 3122, Australia
| | | | - Andrew K Wise
- The Bionics Institute, East Melbourne, VIC 3002, Australia
- Department of Surgery (Otolaryngology), University of Melbourne, The Royal Victorian Eye and Ear Hospital, East Melbourne, VIC 3002, Australia
- Medical Bionics Department, University of Melbourne, East Melbourne, VIC 3002, Australia
| | - James B Fallon
- The Bionics Institute, East Melbourne, VIC 3002, Australia
- Department of Surgery (Otolaryngology), University of Melbourne, The Royal Victorian Eye and Ear Hospital, East Melbourne, VIC 3002, Australia
- Medical Bionics Department, University of Melbourne, East Melbourne, VIC 3002, Australia
| | - Paul R Stoddart
- ARC Training Centre in Biodevices, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Karina Needham
- Department of Surgery (Otolaryngology), University of Melbourne, The Royal Victorian Eye and Ear Hospital, East Melbourne, VIC 3002, Australia
- Author to whom any correspondence should be addressed
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18
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Gietman SW, Silva SM, Del Rosal B, Kapsa RMI, Stoddart PR, Moulton SE. Tuning drug dosing through matching optically active polymer composition and NIR stimulation parameters. Int J Pharm 2020; 575:118976. [PMID: 31857186 DOI: 10.1016/j.ijpharm.2019.118976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 12/13/2019] [Accepted: 12/14/2019] [Indexed: 10/25/2022]
Abstract
Controlled release is at the forefront of modern bioscience as it aims to address challenges associated with the dosing of drugs within required levels for therapeutic effect. Many materials and approaches can be used to control the release from different reservoirs including nanoparticles, liposomes and hydrogels. Using thermoresponsive hydrogels, near infrared illumination of plasmonic nanoparticles can be used to control the hydrogel through localised surface plasmon resonance heating. This work extends beyond a material level and pursues detailed examination of the drug release characteristics of a variable acrylic acid poly(N-isopropylacrylamide) coated gold nanorod system using dexamethasone as a model drug. Release was examined under different irradiation power densities and exposure times. Bulk heating effects in all stimulation protocols did not exceed the lower critical solution temperature of the system, but a marked increase in release was seen following stimulation. This was likely due to more intense heating occurring around the nanorods. A release model was established to describe the amount of drug eluted relative to input energy, suggesting that shorter irradiation periods release the drug more efficiently. The data reported establishes plasmonically modulated thermosensitive hydrogels as a candidate material that can be tailored to specific clinical applications of stimulated release.
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Affiliation(s)
- Shaun W Gietman
- ARC Centre of Excellence for Electromaterials Science, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Saimon M Silva
- ARC Centre of Excellence for Electromaterials Science, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia; BioFab3D@ACMD, St. Vincent's Hospital Melbourne, Fitzroy, VIC 3065, Australia
| | - Blanca Del Rosal
- Centre for Micro-Photonics, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Robert M I Kapsa
- ARC Centre of Excellence for Electromaterials Science, Intelligent Polymer Research Institute, University of Wollongong, Wollongong, NSW 2522, Australia; BioFab3D@ACMD, St. Vincent's Hospital Melbourne, Fitzroy, VIC 3065, Australia
| | - Paul R Stoddart
- ARC Centre of Excellence for Electromaterials Science, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia; ARC Training Centre in Biodevices, Swinburne University of Technology, John Street, Hawthorn, VIC 3122, Australia
| | - Simon E Moulton
- ARC Centre of Excellence for Electromaterials Science, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia; Iverson Health Innovation Research Institute, Swinburne University of Technology, Hawthorn, VIC 3122, Australia.
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19
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Perera MNMN, Schmidt D, Gibbs WEK, Juodkazis S, Stoddart PR. Influence of the dielectric substrate on the effective optical constants of silver plasmonic films. Appl Opt 2019; 58:6038-6044. [PMID: 31503924 DOI: 10.1364/ao.58.006038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 07/04/2019] [Indexed: 06/10/2023]
Abstract
The effective optical properties of plasmonic thin films can be used to model the far-field response of nanostructured materials to an incident electromagnetic field. In the present work, optically thin nanostructured silver (Ag) plasmonic films were fabricated on transparent dielectric substrates of soda-lime glass, sapphire, and fused silica using oblique angle deposition. The influence of the underlying dielectric substrate on the effective optical properties of the nanostructured layer was investigated by an ellipsometric-optical model based on Mueller matrix ellipsometry. The wavelength-dependent uniaxial optical responses of the nanostructured Ag films fabricated on sapphire were modeled with three Gaussian and one Tanguy oscillator, representing key optical phenomena over the range from 300 to 1000 nm. In comparison with the same Ag films on glass, the results confirm that the effective optical properties cannot be considered in isolation from the substrate. As expected, the extinction peak associated with the localized surface plasmon resonance was redshifted by approximately 220 nm per unit of the substrate refractive index. Importantly, it was found that the direction of incidence also influences the film behavior, with a substantial redshift in the extinction peak for light directed through the dielectric compared to free-space illumination. This property can have a significant effect on the far-field performance of these films.
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Duc D, Stoddart PR, McArthur SL, Kapsa RMI, Quigley AF, Boyd‐Moss M, Moulton SE. Electrical Cell Stimulation: Fabrication of a Biocompatible Liquid Crystal Graphene Oxide–Gold Nanorods Electro‐ and Photoactive Interface for Cell Stimulation (Adv. Healthcare Mater. 9/2019). Adv Healthc Mater 2019. [DOI: 10.1002/adhm.201970036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Daniela Duc
- ARC Centre of Excellence for Electromaterials ScienceFaculty of Science, Engineering and TechnologySwinburne University of Technology John St Hawthorn VIC 3122 Australia
| | - Paul R. Stoddart
- ARC Centre of Excellence for Electromaterials ScienceFaculty of Science, Engineering and TechnologySwinburne University of Technology John St Hawthorn VIC 3122 Australia
- ARC Training Centre in BiodevicesSwinburne University of Technology John St Hawthorn VIC 3122 Australia
| | - Sally L. McArthur
- ARC Centre of Excellence for Electromaterials ScienceFaculty of Science, Engineering and TechnologySwinburne University of Technology John St Hawthorn VIC 3122 Australia
- ARC Training Centre in BiodevicesSwinburne University of Technology John St Hawthorn VIC 3122 Australia
| | - Robert M. I. Kapsa
- ARC Centre of Excellence for Electromaterials ScienceIntelligent Polymer Research Institute AIIMUniversity of Wollongong Innovation Campus Squires Way North Wollongong NSW 2500 Australia
- Department of MedicineSt Vincent's HospitalThe University of Melbourne 41 Victoria Parade Fitzroy VIC 3065 Australia
- Biofab3D@ACMDSt. Vincent's Hospital 41 Victoria Parade Fitzroy VIC 3065 Australia
| | - Anita F. Quigley
- ARC Centre of Excellence for Electromaterials ScienceIntelligent Polymer Research Institute AIIMUniversity of Wollongong Innovation Campus Squires Way North Wollongong NSW 2500 Australia
- Department of MedicineSt Vincent's HospitalThe University of Melbourne 41 Victoria Parade Fitzroy VIC 3065 Australia
- Biofab3D@ACMDSt. Vincent's Hospital 41 Victoria Parade Fitzroy VIC 3065 Australia
| | - Mitchell Boyd‐Moss
- Biofab3D@ACMDSt. Vincent's Hospital 41 Victoria Parade Fitzroy VIC 3065 Australia
- School of EngineeringRMIT University 124 La Trobe St Melbourne VIC 3000 Australia
| | - Simon E. Moulton
- ARC Centre of Excellence for Electromaterials ScienceFaculty of Science, Engineering and TechnologySwinburne University of Technology John St Hawthorn VIC 3122 Australia
- Iverson Health Innovation Research InstituteSwinburne University of Technology John St Hawthorn VIC 3122 Australia
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21
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Caballero Aguilar LM, Kapsa RM, O'Connell CD, McArthur SL, Stoddart PR, Moulton SE. Controlled release from PCL-alginate microspheres via secondary encapsulation using GelMA/HAMA hydrogel scaffolds. Soft Matter 2019; 15:3779-3787. [PMID: 30989161 DOI: 10.1039/c8sm02575d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Controlling the release of bioactive agents has important potential applications in tissue engineering. While microspheres have been investigated to manipulate release rates, the majority of these investigations have been based on delivery into aqueous media, whereas the cellular environment in tissue engineering is more typically a hydrogel scaffold. If drug-loaded microspheres are introduced within scaffolds to deliver biologically active substances in situ, it is crucial to understand how the release rate is influenced by interactions between the microspheres and the scaffold. Here, we report the fabrication and characterization of a biodegradable scaffold that contains composite microspheres and is suitable for biological applications. Our approach evaluates the influence on the release profile of a model drug (FITC-dextran sulfate) from alginate and PCL-alginate microspheres within a hydrogel construct forming a secondary encapsulation. Increasing the degree of crosslinking in the secondary encapsulation matrix led to a slower cumulative release from 36% to 15%, from the alginate microspheres, whereas a decrease from 26% to 6% was observed for the PCL-alginate microspheres. These results suggest that the release of bioactive molecules can be fine tuned by independently engineering the properties of the scaffold and microspheres.
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Affiliation(s)
- Lilith M Caballero Aguilar
- ARC Centre of Excellence for Electromaterials Science, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, 3122, Australia.
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Duc D, Stoddart PR, McArthur SL, Kapsa RMI, Quigley AF, Boyd‐Moss M, Moulton SE. Fabrication of a Biocompatible Liquid Crystal Graphene Oxide-Gold Nanorods Electro- and Photoactive Interface for Cell Stimulation. Adv Healthc Mater 2019; 8:e1801321. [PMID: 30838818 DOI: 10.1002/adhm.201801321] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 01/25/2019] [Indexed: 01/08/2023]
Abstract
For decades, electrode-tissue interfaces are pursued to establish electrical stimulation as a reliable means to control neuronal cells behavior. However, spreading of electrical currents in tissues limits its spatial precision. Thus, optical cues, such as near-infrared (NIR) light, are explored as alternatives. Presently, NIR stimulation requires higher energy input than electrical methods despite introduction of light absorbers, e.g., gold nanoparticles. As potential solution, NIR and electrical costimulation are proposed but with limited interfaces capable of sustaining this stimulation technique. Here, a novel electroactive nanocomposite with photoactive properties in the NIR range is constructed by N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride/N-hydroxysulfosuccinimide sodium (EDC)/NHS conjugation of liquid crystal graphene oxide (LCGO) to protein-coated gold nanorods (AuNR). The liquid crystal graphene oxide-gold nanorod nanocomposite (LCGO-AuNR) is fabricated into a hydrophilic electrode-coating via drop-casting, making it appropriate for versatile electrode-tissue interface fabrication. UV-vis spectrophotometry results demonstrate that LCGO-AuNR presents an absorbance peak at 798 nm (NIR range). Cyclic voltammetry measurements further confirm its electroactive capacitive properties. Furthermore, LCGO-AuNR coating supports cell adhesion, proliferation, and differentiation of NG108-15 neuronal cells. This biocompatible interface is anticipated, with ideal electrical and optical properties for NIR and electrical costimulation, to enable further development of the technique for energy-efficient and precise neuronal cell modulation.
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Affiliation(s)
- Daniela Duc
- ARC Centre of Excellence for Electromaterials ScienceFaculty of Science, Engineering and TechnologySwinburne University of Technology John St Hawthorn VIC 3122 Australia
| | - Paul R. Stoddart
- ARC Centre of Excellence for Electromaterials ScienceFaculty of Science, Engineering and TechnologySwinburne University of Technology John St Hawthorn VIC 3122 Australia
- ARC Training Centre in BiodevicesSwinburne University of Technology John St Hawthorn VIC 3122 Australia
| | - Sally L. McArthur
- ARC Centre of Excellence for Electromaterials ScienceFaculty of Science, Engineering and TechnologySwinburne University of Technology John St Hawthorn VIC 3122 Australia
- ARC Training Centre in BiodevicesSwinburne University of Technology John St Hawthorn VIC 3122 Australia
| | - Robert M. I. Kapsa
- ARC Centre of Excellence for Electromaterials ScienceIntelligent Polymer Research Institute AIIMUniversity of Wollongong Innovation Campus Squires Way North Wollongong NSW 2500 Australia
- Department of MedicineSt Vincent's HospitalThe University of Melbourne 41 Victoria Parade Fitzroy VIC 3065 Australia
- Biofab3D@ACMDSt. Vincent's Hospital 41 Victoria Parade Fitzroy VIC 3065 Australia
| | - Anita F. Quigley
- ARC Centre of Excellence for Electromaterials ScienceIntelligent Polymer Research Institute AIIMUniversity of Wollongong Innovation Campus Squires Way North Wollongong NSW 2500 Australia
- Department of MedicineSt Vincent's HospitalThe University of Melbourne 41 Victoria Parade Fitzroy VIC 3065 Australia
- Biofab3D@ACMDSt. Vincent's Hospital 41 Victoria Parade Fitzroy VIC 3065 Australia
| | - Mitchell Boyd‐Moss
- Biofab3D@ACMDSt. Vincent's Hospital 41 Victoria Parade Fitzroy VIC 3065 Australia
- School of EngineeringRMIT University 124 La Trobe St Melbourne VIC 3000 Australia
| | - Simon E. Moulton
- ARC Centre of Excellence for Electromaterials ScienceFaculty of Science, Engineering and TechnologySwinburne University of Technology John St Hawthorn VIC 3122 Australia
- Iverson Health Innovation Research InstituteSwinburne University of Technology John St Hawthorn VIC 3122 Australia
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Hutchinson MR, Stoddart PR, Mahadevan-Jansen A. Challenges and opportunities in neurophotonics discussed at the International Conference on Biophotonics 2017. Neurophotonics 2018; 5:040402. [PMID: 30450362 PMCID: PMC6225684 DOI: 10.1117/1.nph.5.4.040402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 09/26/2018] [Indexed: 06/09/2023]
Abstract
Neurophotonics is an exploding field that spans the intersection of light and neurons for fundamental discovery and clinical translation. Optical technologies have significantly impacted brain research by probing into the mysteries of the brain, modulating brain activity, and improving patient care. Based on a discussion held at the International Conference on Biophotonics 2017, a group of leading researchers brainstormed to identify areas of unmet need in neuroscience and medicine, where biophotonics research could have the highest affect. We present two areas of future growth that spans basic research and clinical needs: management of chronic pain and interventional neuroimmunology. There are many directions within these areas that could be pursued for the ultimate goal of improved understanding of the brain and enhanced care of patients with neurological disorders.
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Affiliation(s)
- Mark R. Hutchinson
- University of Adelaide, ARC Centre of Excellence for Nanoscale Biophotonics (CNBP), Adelaide, Australia
| | - Paul R. Stoddart
- Swinburne University of Technology, ARC Training Center in Biodevices, Melbourne, Australia
| | - Anita Mahadevan-Jansen
- Vanderbilt University, Biophotonics Center and Department of Biomedical Engineering, Nashville, Tennessee, United States
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24
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Perera MNMN, Schmidt D, Gibbs WEK, Juodkazis S, Stoddart PR. Effective optical constants of anisotropic silver nanoparticle films with plasmonic properties: erratum. Opt Lett 2017; 42:1092. [PMID: 28295100 DOI: 10.1364/ol.42.001092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This erratum reports a correction to Fig. 5 in the original manuscript, Opt. Lett.41, 5495 (2016)OPLEDP0146-959210.1364/OL.41.005495.
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Balčytis A, Ryu M, Seniutinas G, Stoddart PR, Al Mamun MA, Morikawa J, Juodkazis S. Nano-rescaling of gold films on polystyrene: thermal management for SERS. Nanoscale 2017; 9:690-695. [PMID: 27957572 DOI: 10.1039/c6nr06904e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Nano-textured Au surfaces were prepared on pre-stretched 2D polystyrene (PS) sheets sputtered with different thicknesses of Au. The Au-coated PS was subjected to thermal annealing above the glass transition temperature at ∼150 °C, thus undergoing surface area rescaling via a volume phase transition. The yellow color of the Au changed from the typical mirror-like appearance to a diffusive dark yellow, progressing to dark brown at the smallest feature size, hence, electromagnetic energy was coupled into the substrate. While the surface area footprint is the same after shrinking the PS, the roughness can be modified from the nano- to the micro-scale for different initial thicknesses of sputtered Au. The nanometer-sized features of surface wrinkles on the Au films make them suitable for surface-enhanced Raman scattering (SERS) sensors that can reach ∼104 counts per s per mW. The thermal diffusivity of the contracted surfaces was determined by a non-contact temperature wave method and was larger than that of PS (α ≃ 1.1 × 10-7 m2 s-1) with a linear scaling on the Au thickness: each 10 nm addition of Au increased the diffusivity by 4%. This allows improved heat dissipation from the laser irradiated spot during SERS measurements.
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Affiliation(s)
- Armandas Balčytis
- School of Science, Swinburne University of Technology, John St., Hawthorn, Victoria 3122, Australia. and Department of Laser Technologies, Center for Physical Sciences and Technology, Savanoriu Ave. 231, LT-02300 Vilnius, Lithuania
| | - Meguya Ryu
- Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8550, Japan.
| | - Gediminas Seniutinas
- School of Science, Swinburne University of Technology, John St., Hawthorn, Victoria 3122, Australia.
| | - Paul R Stoddart
- ARC Training Centre in Biodevices, Swinburne University of Technology, John St., Hawthorn, Victoria 3122, Australia
| | - Md Abdullah Al Mamun
- School of Science, Swinburne University of Technology, John St., Hawthorn, Victoria 3122, Australia.
| | - Junko Morikawa
- Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8550, Japan.
| | - Saulius Juodkazis
- School of Science, Swinburne University of Technology, John St., Hawthorn, Victoria 3122, Australia. and Center for Nanotechnology, King Abdulaziz University, Jeddah 21589, Saudi Arabia and Melbourne Centre for Nanofabrication, the Victorian Node of the Australian National Fabrication Facility, 151 Wellington Rd, Clayton, VIC 3168, Australia
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Perera MNMN, Schmidt D, Gibbs WEK, Juodkazis S, Stoddart PR. Effective optical constants of anisotropic silver nanoparticle films with plasmonic properties. Opt Lett 2016; 41:5495-5498. [PMID: 27906222 DOI: 10.1364/ol.41.005495] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Mueller matrix ellipsometry has been used to determine the effective optical constants of island-like Ag films deposited by thermal evaporation. These films depart substantially from bulk silver with a prominent localized surface plasmon resonance. Moreover, despite the isotropic appearance, they exhibit uniaxial optical properties with the optical axis inclined by 83.4° from the substrate normal toward the direction of the incoming vapor flux. The uniaxial model supports the plasmon resonance peaks revealed by in-plane absorbance measurements of the films. The uniaxial behavior suggests that the resonances along the ordinary axes are weakly coupled between neighboring particles, whereas the extraordinary resonance is relatively strongly coupled. Therefore, the anisotropy should be considered in the practical applications of these plasmonic films.
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Javed MA, Neil WC, Stoddart PR, Wade SA. Influence of carbon steel grade on the initial attachment of bacteria and microbiologically influenced corrosion. Biofouling 2016; 32:109-122. [PMID: 26785935 DOI: 10.1080/08927014.2015.1128528] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The influence of the composition and microstructure of different carbon steel grades on the initial attachment (≤ 60 min) of Escherichia coli and subsequent longer term (28 days) corrosion was investigated. The initial bacterial attachment increased with time on all grades of carbon steel. However, the rate and magnitude of bacterial attachment varied on the different steel grades and was significantly less on the steels with a higher pearlite phase content. The observed variations in the number of bacterial cells attached across different steel grades were significantly reduced by applying a fixed potential to the steel samples. Longer term immersion studies showed similar levels of biofilm formation on the surface of the different grades of carbon steel. The measured corrosion rates were significantly higher in biotic conditions compared to abiotic conditions and were found to be positively correlated with the pearlite phase content of the different grades of carbon steel coupons.
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Affiliation(s)
- M A Javed
- a Faculty of Science, Engineering and Technology , Swinburne University of Technology , Hawthorn , Victoria , Australia
- b Defence Materials Technology Centre (DMTC) , Melbourne , Australia
| | - W C Neil
- c Defence Science and Technology Group , Melbourne , Australia
| | - P R Stoddart
- a Faculty of Science, Engineering and Technology , Swinburne University of Technology , Hawthorn , Victoria , Australia
- b Defence Materials Technology Centre (DMTC) , Melbourne , Australia
| | - S A Wade
- a Faculty of Science, Engineering and Technology , Swinburne University of Technology , Hawthorn , Victoria , Australia
- b Defence Materials Technology Centre (DMTC) , Melbourne , Australia
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Balčytis A, Ryu M, Seniutinas G, Juodkazytė J, Cowie BCC, Stoddart PR, Zamengo M, Morikawa J, Juodkazis S. Black-CuO: surface-enhanced Raman scattering and infrared properties. Nanoscale 2015; 7:18299-18304. [PMID: 26487549 DOI: 10.1039/c5nr04783h] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Large surface area samples of nanotextured black CuO were prepared by chemical etching of Cu for use in surface-enhanced Raman scattering (SERS). The SERS intensity of a self-assembled monolayer (SAM) of thiophenol was proportional to the thickness of a nanoscale-conformal Au film deposited by magnetron sputtering over the black CuO. A very high SERS yield of ∼10(4) counts per s per mW was observed for the thiophenol SAM on the thickest Au films studied here. Synchrotron X-ray photoelectron spectroscopy was used to confirm that the surface of the chemically etched Cu was covered by high purity CuO. IR spectral characterization of the black CuO showed a close to linear increase in reflectivity from 25 to 100% over the range of 4000-500 cm(-1) wavenumbers (or 2.5-20 μm in wavelength). Sensing applications and thermal effects in SERS are discussed.
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Affiliation(s)
- Armandas Balčytis
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, John Street, Hawthorn, VIC 3122, Australia. and Center for Physical Sciences and Technology, A. Goštauto 9, LT-01108 Vilnius, Lithuania
| | - Meguya Ryu
- Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8550, Japan
| | - Gediminas Seniutinas
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, John Street, Hawthorn, VIC 3122, Australia.
| | - Jurga Juodkazytė
- Center for Physical Sciences and Technology, A. Goštauto 9, LT-01108 Vilnius, Lithuania
| | - Bruce C C Cowie
- Australian Synchrotron, 800 Blackburn Rd., Clayton, VIC 3168, Australia
| | - Paul R Stoddart
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, John Street, Hawthorn, VIC 3122, Australia.
| | | | - Junko Morikawa
- Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8550, Japan
| | - Saulius Juodkazis
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, John Street, Hawthorn, VIC 3122, Australia. and Center for Nanotechnology, King Abdulaziz University, Jeddah 21589, Saudi Arabia
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Hartley JS, Hlaing MM, Seniutinas G, Juodkazis S, Stoddart PR. Black silicon as a platform for bacterial detection. Biomicrofluidics 2015; 9:061101. [PMID: 26576207 PMCID: PMC4636504 DOI: 10.1063/1.4934966] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 10/20/2015] [Indexed: 05/26/2023]
Abstract
Surface-enhanced Raman scattering (SERS) shows promise for identifying single bacteria, but the short range nature of the effect makes it most sensitive to the cell membrane, which provides limited information for species-level identification. Here, we show that a substrate based on black silicon can be used to impale bacteria on nanoscale SERS-active spikes, thereby producing spectra that convey information about the internal composition of the bacterial capsule. This approach holds great potential for the development of microfluidic devices for the removal and identification of single bacteria in important clinical diagnostics and environmental monitoring applications.
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Affiliation(s)
- Jennifer S Hartley
- Faculty of Science, Engineering and Technology, Swinburne University of Technology , Hawthorn, Victoria 3122, Australia
| | - M Myintzu Hlaing
- Faculty of Science, Engineering and Technology, Swinburne University of Technology , Hawthorn, Victoria 3122, Australia
| | | | | | - Paul R Stoddart
- Faculty of Science, Engineering and Technology, Swinburne University of Technology , Hawthorn, Victoria 3122, Australia
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Affiliation(s)
- Chiara Paviolo
- Centre for Micro-Photonics, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Victoria, Australia
| | - Paul R Stoddart
- Industrial Research Institute Swinburne, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Victoria, Australia
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31
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Buividas R, Dzingelevičius N, Kubiliūtė R, Stoddart PR, Khanh Truong V, Ivanova EP, Juodkazis S. Statistically quantified measurement of an Alzheimer's marker by surface-enhanced Raman scattering. J Biophotonics 2015; 8:567-74. [PMID: 25116238 DOI: 10.1002/jbio.201400017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 05/15/2014] [Accepted: 07/03/2014] [Indexed: 05/06/2023]
Abstract
Fibrillar forms of the Amyloid-β (Aβ) protein have been implicated in the early stages of Alzheimer's disease (AD), however there are no standardised assays for soluble Aβ oligomer biomarkers that provide the best indication of the disease progression [1,2]. As a step towards a fast and label-free method for testing different AD biomarkers, we have combined laser nano-textured substrates with a SERS mapping technique and validated it using soluble Aβ-40 oligomers [3-5]. The nano-textured SERS substrates provide fast (&5 min), label-free spectra associated with soluble Aβ-40 oligomers down to a concentration of 10 nM. Statistical analysis of the spectral intensities mapped over the substrate surface shows a quantitative correlation with the oligomer concentration. Schematics of experiments: SERS mapping of Aβ-40 (left figure: measured SERS intensity overlayed with an SEM image of ripples) was carried out on the laser nano-textured (ripple) surface of sapphire and statistical analysis of the SERS intensity was carried out for qualitative (a high SERS intensity at low probability) and quantitative (a moderate SERS intenisty at the highest probability) measures. Quantitative statistical analysis of SERS mapping data can be performed off line for cross correlations with other known SERS signatures.
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Affiliation(s)
- Ričardas Buividas
- Centre for Micro-Photonics and The Australian National Fabrication Facility - ANFF, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Nerijus Dzingelevičius
- Centre for Micro-Photonics and The Australian National Fabrication Facility - ANFF, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
- Department of Bioelectrochemistry and Biospectroscopy, Vilnius University Institute of Biochemistry, Mokslininkų 12, LT-08662 Vilnius, Lithuania
| | - Reda Kubiliūtė
- Centre for Micro-Photonics and The Australian National Fabrication Facility - ANFF, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
- Laboratory of Biomedical Physics, Vilnius University Institute of Oncology, Baublio 3A, Vilnius, LT-08406, Lithuania
- Research Centre for Microsystems and Nanotechnology, Kaunas University of Technology, Studentu 65, LT-51369, Kaunas, Lithuania
| | - Paul R Stoddart
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Vi Khanh Truong
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Elena P Ivanova
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Saulius Juodkazis
- Centre for Micro-Photonics and The Australian National Fabrication Facility - ANFF, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
- Melbourne Centre for Nanofabrication, Australian National Fabrication Facility, Clayton, VIC 3168, Australia
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Abstract
Recent studies have demonstrated that nerves can be stimulated in a variety of ways by the transient heating associated with the absorption of infrared light by water in neuronal tissue. This technique holds great potential for replacing or complementing standard stimulation techniques, due to the potential for increased localization of the stimulus and minimization of mechanical contact with the tissue. However, optical approaches are limited by the inability of visible light to penetrate deep into tissues. Moreover, thermal modelling suggests that cumulative heating effects might be potentially hazardous when multiple stimulus sites or high laser repetition rates are used. The protocol outlined below describes an enhanced approach to the infrared stimulation of neuronal cells. The underlying mechanism is based on the transient heating associated with the optical absorption of gold nanorods, which can cause triggering of neuronal cell differentiation and increased levels of intracellular calcium activity. These results demonstrate that nanoparticle absorbers can enhance and/or replace the process of infrared neural stimulation based on water absorption, with potential for future applications in neural prostheses and cell therapies.
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Affiliation(s)
- Chiara Paviolo
- Biotactical Engineering, Faculty of Science, Engineering and Technology, Swinburne University of Technology;
| | - Sally L McArthur
- Biotactical Engineering, Faculty of Science, Engineering and Technology, Swinburne University of Technology
| | - Paul R Stoddart
- Biotactical Engineering, Faculty of Science, Engineering and Technology, Swinburne University of Technology
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Seniutinas G, Gervinskas G, Verma R, Gupta BD, Lapierre F, Stoddart PR, Clark F, McArthur SL, Juodkazis S. Versatile SERS sensing based on black silicon. Opt Express 2015; 23:6763-6772. [PMID: 25836894 DOI: 10.1364/oe.23.006763] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Black Si (b-Si) with gold or silver metal coating has been shown to be an extremely effective substrate for surface-enhanced Raman scattering (SERS). Here, we demonstrate that it is also a highly versatile SERS platform, as it supports a wide range of surface functionalizations. In particular, we report the use of a molecularly imprinted polymer (MIP) coating and a hydrophobic coating on b-Si to establish two different sensing modalities. First, using a MIP layer on Au-coated b-Si, we show selective sensing of two closely related varieties of tetracycline. Second, a hydrophobic coating was used to concentrate the analyte adsorbed on gold colloidal nanoparticles, thus increasing the sensitivity of the measurement by an order of magnitude. In this experiment, Au nanoparticles and analyte were mixed just before SERS measurements and were concentrated by drop-drying on the super-hydrophobic b-Si. These approaches are promising for SERS measurements that are sensitive to the aging of bare plasmonic metal-coated substrates.
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Abstract
Our capacity to interface with the nervous system remains overwhelmingly reliant on electrical stimulation devices, such as electrode arrays and cuff electrodes that can stimulate both central and peripheral nervous systems. However, electrical stimulation has to deal with multiple challenges, including selectivity, spatial resolution, mechanical stability, implant-induced injury and the subsequent inflammatory response. Optical stimulation techniques may avoid some of these challenges by providing more selective stimulation, higher spatial resolution and reduced invasiveness of the device, while also avoiding the electrical artefacts that complicate recordings of electrically stimulated neuronal activity. This review explores the current status of optical stimulation techniques, including optogenetic methods, photoactive molecule approaches and infrared neural stimulation, together with emerging techniques such as hybrid optical-electrical stimulation, nanoparticle enhanced stimulation and optoelectric methods. Infrared neural stimulation is particularly emphasised, due to the potential for direct activation of neural tissue by infrared light, as opposed to techniques that rely on the introduction of exogenous light responsive materials. However, infrared neural stimulation remains imperfectly understood, and techniques for accurately delivering light are still under development. While the various techniques reviewed here confirm the overall feasibility of optical stimulation, a number of challenges remain to be overcome before they can deliver their full potential.
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Affiliation(s)
- Alexander C Thompson
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Australia
| | - Paul R Stoddart
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Australia
| | - E Duco Jansen
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
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Walia S, Shah AK, Stoddart PR, Bhaskaran M, Sriram S. Electric field induced surface-enhanced Raman spectroscopy for multianalyte detection. Phys Chem Chem Phys 2015; 17:7095-9. [DOI: 10.1039/c4cp04912h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
This work demonstrates the ability to detect and isolate an analyte from a multianalyte mixture by SERS sensing.
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Affiliation(s)
- Sumeet Walia
- Functional Materials and Microsystems Research Group
- RMIT University
- Melbourne
- Australia
- Micro Nano Research Facility
| | - Aditya K. Shah
- Functional Materials and Microsystems Research Group
- RMIT University
- Melbourne
- Australia
- Micro Nano Research Facility
| | - Paul R. Stoddart
- Faculty of Engineering and Industrial Science
- Swinburne University of Technology
- Hawthorn
- Australia
| | - Madhu Bhaskaran
- Functional Materials and Microsystems Research Group
- RMIT University
- Melbourne
- Australia
- Micro Nano Research Facility
| | - Sharath Sriram
- Functional Materials and Microsystems Research Group
- RMIT University
- Melbourne
- Australia
- Micro Nano Research Facility
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36
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Yong J, Needham K, Brown WGA, Nayagam BA, McArthur SL, Yu A, Stoddart PR. Gold-nanorod-assisted near-infrared stimulation of primary auditory neurons. Adv Healthc Mater 2014; 3:1862-8. [PMID: 24799427 DOI: 10.1002/adhm.201400027] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Revised: 02/21/2014] [Indexed: 12/21/2022]
Abstract
Infrared stimulation offers an alternative to electrical stimulation of neuronal tissue, with potential for direct, non-contact activation at high spatial resolution. Conventional methods of infrared neural stimulation (INS) rely on transient heating due to the absorption of relatively intense laser beams by water in the tissue. However, the water absorption also limits the depth of penetration of light in tissue. Therefore, the use of a near-infrared laser at 780 nm to stimulate cultured rat primary auditory neurons that are incubated with silica-coated gold nanorods (Au NRs) as an extrinsic absorber is investigated. The laser-induced electrical behavior of the neurons is observed using whole-cell patch clamp electrophysiology. The nanorod-treated auditory neurons (NR-ANs) show a significant increase in electrical activity compared with neurons that are incubated with non-absorbing silica-coated gold nanospheres and control neurons with no gold nanoparticles. The laser-induced heating by the nanorods is confirmed by measuring the transient temperature increase near the surface of the NR-ANs with an open pipette electrode. These findings demonstrate the potential to improve the efficiency and increase the penetration depth of INS by labeling nerves with Au NRs and then exposing them to infrared wavelengths in the water window of tissue.
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Affiliation(s)
- Jiawey Yong
- Faculty of Science, Engineering and Technology; Swinburne University of Technology; P. O. Box 218 Hawthorn Victoria 3122 Australia
| | - Karina Needham
- Department of Otolaryngology; University of Melbourne; East Melbourne Victoria 3002 Australia
| | - William G. A. Brown
- Faculty of Science, Engineering and Technology; Swinburne University of Technology; P. O. Box 218 Hawthorn Victoria 3122 Australia
| | - Bryony A. Nayagam
- Department of Audiology and Speech Pathology; University of Melbourne; Carlton Victoria 3010 Australia
| | - Sally L. McArthur
- Faculty of Science, Engineering and Technology; Swinburne University of Technology; P. O. Box 218 Hawthorn Victoria 3122 Australia
| | - Aimin Yu
- Faculty of Science, Engineering and Technology; Swinburne University of Technology; P. O. Box 218 Hawthorn Victoria 3122 Australia
| | - Paul R. Stoddart
- Faculty of Science, Engineering and Technology; Swinburne University of Technology; P. O. Box 218 Hawthorn Victoria 3122 Australia
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Paviolo C, Haycock JW, Cadusch PJ, McArthur SL, Stoddart PR. Laser exposure of gold nanorods can induce intracellular calcium transients. J Biophotonics 2014; 7:761-5. [PMID: 23798060 DOI: 10.1002/jbio.201300043] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Revised: 05/12/2013] [Accepted: 06/03/2013] [Indexed: 05/08/2023]
Abstract
Uncoated and poly(styrene sulphonate) (PSS)-coated gold nanorods were taken up by NG108-15 neuronal cells. Exposure to 780 nm laser light at the plasmon resonance wavelength of the gold nanorods was found to induce intracellular Ca(2+) transients. The higher Ca(2+) peaks were observed at lower laser doses, with the highest levels obtained at a radiant exposure of 0.33 J/cm(2) . In contrast, the cells without nanoparticles showed a consistently small response, independent of the laser dose. These initial results open up new opportunities for peripheral nerve regeneration treatments and for more efficient optical stimulation techniques.
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Affiliation(s)
- Chiara Paviolo
- Biotactical Engineering, Industrial Research Institute Swinburne, Faculty of Engineering and Industrial Science, Swinburne University of Technology, Hawthorn, PO Box 218, Victoria 3122, Australia
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39
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Miao L, Stoddart PR, Hsiang TY. Novel aluminum near field transducer and highly integrated micro-nano-optics design for heat-assisted ultra-high-density magnetic recording. Nanotechnology 2014; 25:295202. [PMID: 24981413 DOI: 10.1088/0957-4484/25/29/295202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Heat-assisted magnetic recording (HAMR) has attracted increasing attention as one of the most promising future techniques for ultra-high-density magnetic recording beyond the current limit of 1 Tb in(-2). Localized surface plasmon resonance plays an important role in HAMR by providing a highly focused optical spot for heating the recording medium within a small volume. In this work, we report an aluminum near-field transducer (NFT) based on a novel bow-tie design. At an operating wavelength of 450 nm, the proposed transducer can generate a 35 nm spot size inside the magnetic recording medium, corresponding to a recording density of up to 2 Tb in(-2). A highly integrated micro-nano-optics design is also proposed to ensure process compatibility and corrosion-resistance of the aluminum NFT. Our work has demonstrated the feasibility of using aluminum as a plasmonic material for HAMR, with advantages of reduced cost and improved efficiency compared to traditional noble metals.
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Affiliation(s)
- Lingyun Miao
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY 14627, USA
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40
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Kostovski G, Stoddart PR, Mitchell A. The optical fiber tip: an inherently light-coupled microscopic platform for micro- and nanotechnologies. Adv Mater 2014; 26:3798-820. [PMID: 24599822 DOI: 10.1002/adma.201304605] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 01/20/2014] [Indexed: 05/27/2023]
Abstract
The flat tip of an optical fiber is a unique and unconventional platform for micro and nanotechnologies. The small cross-section and large aspect ratio of the fiber provide an inherently light-coupled substrate that is uniquely suited to remote, in vivo and in situ applications. However, these same characteristics challenge established fabrication technologies, which are best suited to large planar substrates. This review presents a broad overview of strategies for patterning the flat tip of an optical fiber. Techniques discussed include self-assembly, numerous lithographies, through-fiber patterning, hybrid techniques, and strategies for mass manufacture, while the diverse applications are discussed in context throughout.
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Affiliation(s)
- Gorgi Kostovski
- Microplatforms Research Group, School of Electrical and Computer Engineering, RMIT University, Melbourne, Victoria, Australia
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41
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Wade SA, Fallon JB, Wise AK, Shepherd RK, James NL, Stoddart PR. Measurement of Forces at the Tip of a Cochlear Implant During Insertion. IEEE Trans Biomed Eng 2014; 61:1177-86. [DOI: 10.1109/tbme.2013.2296566] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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42
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Wang Y, Chang TC, Stoddart PR, Chang HC. Diffraction-limited ultrasensitive molecular nano-arrays with singular nano-cone scattering. Biomicrofluidics 2014; 8:021101. [PMID: 24738011 PMCID: PMC3971819 DOI: 10.1063/1.4869694] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 03/15/2014] [Indexed: 05/07/2023]
Abstract
Large-library fluorescent molecular arrays remain limited in sensitivity (1 × 10(6) molecules) and dynamic range due to background auto-fluorescence and scattering noise within a large (20-100 μm) fluorescent spot. We report an easily fabricated silica nano-cone array platform, with a detection limit of 100 molecules and a dynamic range that spans 6 decades, due to point (10 nm to 1 μm) illumination of preferentially absorbed tagged targets by singular scattering off wedged cones. Its fluorescent spot reaches diffraction-limited submicron dimensions, which are 10(4) times smaller in area than conventional microarrays, with comparable reduction in detection limit and amplification of dynamic range.
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Affiliation(s)
- Yunshan Wang
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Ting-Chou Chang
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Paul R Stoddart
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia
| | - Hsueh-Chia Chang
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
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43
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Chrimes AF, Khoshmanesh K, Stoddart PR, Mitchell A, Kalantar-Zadeh K. Microfluidics and Raman microscopy: current applications and future challenges. Chem Soc Rev 2014; 42:5880-906. [PMID: 23624774 DOI: 10.1039/c3cs35515b] [Citation(s) in RCA: 156] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Raman microscopy systems are becoming increasingly widespread and accessible for characterising chemical species. Microfluidic systems are also progressively finding their way into real world applications. Therefore, it is anticipated that the integration of Raman systems with microfluidics will become increasingly attractive and practical. This review aims to provide an overview of Raman microscopy-microfluidics integrated systems for researchers who are actively interested in utilising these tools. The fundamental principles and application strengths of Raman microscopy are discussed in the context of microfluidics. Various configurations of microfluidics that incorporate Raman microscopy methods are presented, with applications highlighted. Data analysis methods are discussed, with a focus on assisting the interpretation of Raman-microfluidics data from complex samples. Finally, possible future directions of Raman-microfluidic systems are presented.
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Affiliation(s)
- Adam F Chrimes
- School of Electrical and Computer Engineering, RMIT University, 124 LaTrobe St, Melbourne, Australia.
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44
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Hartley JS, Juodkazis S, Stoddart PR. Optical fibers for miniaturized surface-enhanced Raman-scattering probes. Appl Opt 2013; 52:8388-93. [PMID: 24513843 DOI: 10.1364/ao.52.008388] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 11/07/2013] [Indexed: 05/22/2023]
Abstract
A range of optical fibers with surface-enhanced Raman scattering (SERS) functionalized tips have been evaluated for use as micro-scale sensing devices. In order to optimize the sensitivity of the optical fiber probe, the relationship between SERS intensity and different fiber parameters was investigated. It was found that the numerical aperture, core size, mode structure, and core material have a major effect on the probe performance, as does the numerical aperture of the microscope objective. The results suggest that an ideal fiber for SERS sensing should be single mode at the excitation wavelength and have low-background core material.
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45
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Javed MA, Stoddart PR, McArthur SL, Wade SA. The effect of metal microstructure on the initial attachment of Escherichia coli to 1010 carbon steel. Biofouling 2013; 29:939-952. [PMID: 23906317 DOI: 10.1080/08927014.2013.820826] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Metallurgical features have been shown to play an important role in the attachment of microorganisms to metal surfaces. In the present study, the influence of the microstructure of as-received (AR) and heat-treated (HT) 1010 carbon steel on the initial attachment of bacteria was investigated. Heat treatment was carried out with the aim of increasing the grain size of the carbon steel coupons. Mirror-polished carbon steel coupons were immersed in a minimal medium inoculated with Escherichia coli (ATCC 25922) to investigate the early (15, 30 and 60 min) and relatively longer-term (4 h) stages of bacterial attachment. The results showed preferential colonisation of bacteria on the grain boundaries of the steel coupons. The bacterial attachment to AR steel coupons was relatively uniform compared to the HT steel coupons where an increased number of localised aggregates of bacteria were found. Quantitative analysis showed that the ratio of the total number of isolated (i.e., single) bacteria to the number of bacteria in aggregates was significantly higher on the AR coupons than the HT coupons. Longer-term immersion studies showed production of extracellular polymeric substances by the bacteria and corrosion at the grain boundaries on both types of steel coupon tested.
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Affiliation(s)
- M A Javed
- Faculty of Engineering and Industrial Sciences, Biotactical Engineering, IRIS, Swinburne University of Technology, Hawthorn, Australia.
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46
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Brown WGA, Needham K, Nayagam BA, Stoddart PR. Whole cell patch clamp for investigating the mechanisms of infrared neural stimulation. J Vis Exp 2013. [PMID: 23929071 DOI: 10.3791/50444] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
It has been demonstrated in recent years that pulsed, infrared laser light can be used to elicit electrical responses in neural tissue, independent of any further modification of the target tissue. Infrared neural stimulation has been reported in a variety of peripheral and sensory neural tissue in vivo, with particular interest shown in stimulation of neurons in the auditory nerve. However, while INS has been shown to work in these settings, the mechanism (or mechanisms) by which infrared light causes neural excitation is currently not well understood. The protocol presented here describes a whole cell patch clamp method designed to facilitate the investigation of infrared neural stimulation in cultured primary auditory neurons. By thoroughly characterizing the response of these cells to infrared laser illumination in vitro under controlled conditions, it may be possible to gain an improved understanding of the fundamental physical and biochemical processes underlying infrared neural stimulation.
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Affiliation(s)
- William G A Brown
- Biotactical Engineering, Faculty of Engineering and Industrial Science, Swinburne University of Technology
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47
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Kubiliūtė R, Maximova KA, Lajevardipour A, Yong J, Hartley JS, Mohsin ASM, Blandin P, Chon JWM, Sentis M, Stoddart PR, Kabashin A, Rotomskis R, Clayton AHA, Juodkazis S. Ultra-pure, water-dispersed Au nanoparticles produced by femtosecond laser ablation and fragmentation. Int J Nanomedicine 2013; 8:2601-11. [PMID: 23888114 PMCID: PMC3722033 DOI: 10.2147/ijn.s44163] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Aqueous solutions of ultra-pure gold nanoparticles have been prepared by methods of femtosecond laser ablation from a solid target and fragmentation from already formed colloids. Despite the absence of protecting ligands, the solutions could be (1) fairly stable and poly size-dispersed; or (2) very stable and monodispersed, for the two fabrication modalities, respectively. Fluorescence quenching behavior and its intricacies were revealed by fluorescence lifetime imaging microscopy in rhodamine 6G water solution. We show that surface-enhanced Raman scattering of rhodamine 6G on gold nanoparticles can be detected with high fidelity down to micromolar concentrations using the nanoparticles. Application potential of pure gold nanoparticles with polydispersed and nearly monodispersed size distributions are discussed.
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Affiliation(s)
- Reda Kubiliūtė
- Centre for Micro-Photonics and Industrial Research Institute Swinburne, Faculty of Engineering and Industrial Sciences Swinburne University of Technology, Hawthorn, VIC, Australia
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48
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Thompson AC, Wade SA, Pawsey NC, Stoddart PR. Infrared Neural Stimulation: Influence of Stimulation Site Spacing and Repetition Rates on Heating. IEEE Trans Biomed Eng 2013; 60:3534-41. [PMID: 23864150 DOI: 10.1109/tbme.2013.2272796] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A model to simulate heating as a result of pulse repetitions during infrared neural stimulation (INS), with both single- and multiple-emitters is presented. This model allows the temperature increases from pulse trains rather than single pulses to be considered. The model predicts that using a stimulation rate of 250 Hz with typical laser parameters at a single stimulation site results in a temperature increase of 2.3°C. When multiple stimulation sites are used in analogy to cochlear implants, the temperature increases further depending upon the spacing between emitters. However, when the light is more localized at multiple stimulation sites the temperature increase is reduced.
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49
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Paviolo C, Haycock JW, Yong J, Yu A, Stoddart PR, McArthur SL. Laser exposure of gold nanorods can increase neuronal cell outgrowth. Biotechnol Bioeng 2013; 110:2277-91. [PMID: 23456616 DOI: 10.1002/bit.24889] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 02/18/2013] [Accepted: 02/20/2013] [Indexed: 01/27/2023]
Abstract
The usage of gold nanoparticles (Au NPs) in biological applications has risen significantly over the last 10 years. With the wide variety of chemical and biological functionalization available and their distinctive optical properties, Au NPs are currently used in a range of biological applications including sensing, labeling, drug delivery, and imaging applications. Among the available particles, gold nanorods (Au NRs) are particularly useful because their optical absorption can be tuned across the visible to near infrared region. Here, we present a novel application of Au NRs associated with low power laser exposure of NG108-15 neuronal cells. When cells were irradiated with a 780 nm laser, the average number of neurons with neurites increased. A similar stimulatory effect was observed for cells that were cultured with poly-(4-styrenesulfonic acid)-coated and silica-coated Au NRs. Furthermore, when the NG108-15 cells were cultured with both bare and coated Au NRs and then irradiated with 1.2-7.5 W/cm(2) at 780 nm, they showed a neurite length increase of up to 25 µm versus control. To the best of our knowledge, this effect has never been reported before. While the pathways of the stimulation is not yet clear, the data presented here demonstrates that it is linked to the absorption of light by the Au NRs. These initial results open up new opportunities for peripheral nerve regeneration treatments and for novel approaches to addressing central nervous system axons following spinal cord injury.
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Affiliation(s)
- Chiara Paviolo
- Biotactical Engineering, Industrial Research Institute Swinburne (IRIS), Faculty of Engineering and Industrial Science, Swinburne University of Technology, PO Box 218, Hawthorn, Victoria 3122, Australia
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50
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Paviolo C, Clayton AHA, McArthur SL, Stoddart PR. Temperature measurement in the microscopic regime: a comparison between fluorescence lifetime- and intensity-based methods. J Microsc 2013; 250:179-88. [PMID: 23521067 DOI: 10.1111/jmi.12033] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 02/26/2013] [Indexed: 11/26/2022]
Abstract
Thermally sensitive fluorescent indicators have been proposed to monitor temperature changes in microfluidic systems, mainly based on fluorescence intensity or lifetime. However, measuring temperature in a structured environment, such as biological tissue, presents additional challenges due to the chemical and structural complexity. Here, we investigate the potential for resolving temperature distributions within the volume of a single cell. Rhodamine B (RhB) dye was employed as a temperature indicator to compare fluorescence intensity- and lifetime-based techniques. The relationship between the fluorescence lifetime and temperature was found to be highly dependent on the biological environment. The intensity-based method allowed the temperature distribution to be mapped with partial success within the volume of a single cell. Under ideal circumstances, the temperature can be mapped pixel by pixel with a resolution better than ±0.3°C within the cell cytoplasm, but this accuracy was reduced to ±1.8°C by environmental variations. These results suggest that the fluorophore should be encapsulated and immobilized in the biological tissue in order to reduce the influence of environmental factors on temperature measurements at the cellular level.
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Affiliation(s)
- C Paviolo
- Industrial Research Institute Swinburne, Swinburne University of Technology, Hawthorn, Victoria, Australia
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