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Feely N, Wdowicz A, Chevalier A, Wang Y, Li P, Rollo F, Lee GU. Targeting Mucin Protein Enables Rapid and Efficient Ovarian Cancer Cell Capture: Role of Nanoparticle Properties in Efficient Capture and Culture. Small 2023; 19:e2207154. [PMID: 36772896 DOI: 10.1002/smll.202207154] [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: 11/17/2022] [Revised: 01/18/2023] [Indexed: 05/04/2023]
Abstract
The development of specific and sensitive immunomagnetic cell separation nanotechnologies is central to enhancing the diagnostic relevance of circulating tumor cells (CTCs) and improving cancer patient outcomes. The limited number of specific biomarkers used to enrich a phenotypically diverse set of CTCs from liquid biopsies has limited CTC yields and purity. The ultra-high molecular weight mucin, mucin16 (MUC16) is shown to physically shield key membrane proteins responsible for activating immune responses against ovarian cancer cells and may interfere with the binding of magnetic nanoparticles to popular immunomagnetic cell capture antigens. MUC16 is expressed in ≈90% of ovarian cancers and is almost universal in High Grade Serous Epithelial Ovarian Cancer. This work demonstrates that cell bound MUC16 is an effective target for rapid immunomagnetic extraction of expressor cells with near quantitative yield, high purity and viability from serum. The results provide a mechanistic insight into the effects of nanoparticle physical properties and immunomagnetic labeling on the efficiency of immunomagnetic cell isolation. The growth of these cells has also been studied after separation, demonstrating that nanoparticle size impacts cell-particle behavior and growth rate. These results present the successful isolation of "masked" CTCs enabling new strategies for the detection of cancer recurrence and select and monitor chemotherapy.
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Affiliation(s)
- Nathan Feely
- Conway Institute for Biomedical Research and School of Chemistry, University College Dublin, 61 Adair, Sandymount Ave, Dublin, CO. DUBLIN, 00004, Ireland
| | - Anita Wdowicz
- Conway Institute for Biomedical Research and School of Chemistry, University College Dublin, 61 Adair, Sandymount Ave, Dublin, CO. DUBLIN, 00004, Ireland
| | - Anne Chevalier
- Magnostics Ltd, 2 Clifton Lane, Merrion Road, Monkstown, Dublin, A94 A306, Ireland
| | - Ying Wang
- Magnostics Ltd, 2 Clifton Lane, Merrion Road, Monkstown, Dublin, A94 A306, Ireland
| | - Peng Li
- Magnostics Ltd, 2 Clifton Lane, Merrion Road, Monkstown, Dublin, A94 A306, Ireland
| | - Fanny Rollo
- École nationale supérieure des ingénieurs en arts chimiques et technologiques, Toulouse, 31030, France
| | - Gil U Lee
- Conway Institute for Biomedical Research and School of Chemistry, University College Dublin, 61 Adair, Sandymount Ave, Dublin, CO. DUBLIN, 00004, Ireland
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2
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Holohan C, Feely N, Li P, Curran G, Lee GU. Role of detergents and nuclease inhibitors in the extraction of RNA from eukaryotic cells in complex matrices. Nanoscale 2022; 14:12153-12161. [PMID: 35968721 DOI: 10.1039/d2nr02850f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The potential for liquid biopsy samples to be used in place of more invasive tissue biopsies has become increasingly revalent as it has been found that nucleic acids (NAs) present in the blood of cancer patients originate from tumors. Nanomagnetic extraction has proven to be a highly effective means to rapidly prepare NA from clinical samples for molecular diagnostics. In this article, the lysis reaction used to extract RNA from the human epithelial melanoma cells have been optimized using silica coated superparamagnetic nanoparticles (SPM NP). The lysis buffer (LB) is composed of several agents that denature cells, i.e., surfactant and guanidinium isothiocyanate (GITC), and agents that inhibit the degradation of circulated nucleic acids (cfNAs). The surfactant Triton X-100 has been widely used in LB but has been placed on the European Union REACH list. We have compared the qRT-PCR sensitivity resulting from LBs composed of Triton X-100 to several sustainable surfactants, i.e., Tergitol 15-S-7, Tergitol 15-S-9 and Tween-20. Surprisingly, the inclusion of these surfactants in the LB was not found to significantly improve cell lysis, and subsequently the sensitivity of qRT-PCR. The role of the sample matrix was also examined by performing extractions from solutions containing up to 30 mg mL-1 serum albumin. The qRT-PCR sensitivity was found to decrease as the concentration of this protein was increased; however, this was linked to an increased RNase activity and not the concentration of the protein itself. These results lead us to recommend a reformulation of LB for clinical samples, and to conclude that sensitive qRT-PCR RNA analysis can be performed in serum with the timely addition of an RNase inhibitor.
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Affiliation(s)
- Cian Holohan
- Conway Institute for Biomedical Research and School of Chemistry, University College Dublin, Ireland.
| | - Nathan Feely
- Conway Institute for Biomedical Research and School of Chemistry, University College Dublin, Ireland.
| | - Peng Li
- Magnostics Ltd, 2 Clifton Lane, Monkstown, Co Dublin, Ireland
| | - Gerard Curran
- Magnostics Ltd, 2 Clifton Lane, Monkstown, Co Dublin, Ireland
| | - Gil U Lee
- Conway Institute for Biomedical Research and School of Chemistry, University College Dublin, Ireland.
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Holohan C, Hanrahan S, Feely N, Li P, O'Connell J, Moss C, Carr M, Tagit O, Lee GU. Influence of viral transport media and freeze-thaw cycling on the sensitivity of qRT-PCR detection of SARS-CoV-2 nucleic acids. Nanoscale 2021; 13:15659-15667. [PMID: 34533168 DOI: 10.1039/d1nr03933d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Objective: The events of the last year have highlighted the complexity of implementing large-scale molecular diagnostic testing for novel pathogens. The purpose of this study was to determine the chemical influences of sample collection media and storage on the stability and detection of viral nucleic acids by qRT-PCR. We studied the mechanism(s) through which viral transport media (VTM) and number of freeze-thaw cycles influenced the analytical sensitivity of qRT-PCR detection of SARS-CoV-2. Our goal is to reinforce testing capabilities and identify weaknesses that could arise in resource-limited environments that do not have well-controlled cold chains. Method: The sensitivity of qRT-PCR analysis was studied in four VTM for synthetic single-stranded RNA (ssRNA) and double-stranded DNA (dsDNA) simulants of the SARS-CoV-2 genome. Results: The sensitivity and reproducibility of qRT-PCR for the synthetic ssRNA and dsDNA were found to be highly sensitive to VTM with the best results observed for ssRNA in HBSS and PBS-G. Surprisingly, the presence of epithelial cellular material with the ssRNA increased the sensitivity of the qRT-PCR assay. Repeated freeze-thaw cycling decreased the sensitivity of the qRT-PCR with two noted exceptions. Conclusions: The choice of VTM is critically important to defining the sensitivity of COVID-19 molecular diagnostics assays and this study suggests they can impact upon the stability of the SARS-CoV-2 viral genome. This becomes increasingly important if the virus structure is destabilised before analysis, which can occur due to poor storage conditions. This study suggests that COVID-19 testing performed with glycerol-containing PBS will produce a high level of stability and sensitivity. These results are in agreement with clinical studies reported for patient-derived samples.
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Affiliation(s)
- Cian Holohan
- School of Chemistry and Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Republic of Ireland.
| | - Sophia Hanrahan
- School of Chemistry and Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Republic of Ireland.
| | - Nathan Feely
- School of Chemistry and Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Republic of Ireland.
| | - Peng Li
- Magnostics Ltd, Monkstown, Co. Dublin, Republic of Ireland.
| | - John O'Connell
- School of Chemistry and Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Republic of Ireland.
| | - Catherine Moss
- School of Chemistry and Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Republic of Ireland.
| | - Michael Carr
- National Virus Reference Laboratory, University College Dublin, Belfield, Dublin, Republic of Ireland
- International Collaboration Unit, Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Oya Tagit
- Magnostics Ltd, Monkstown, Co. Dublin, Republic of Ireland.
| | - Gil U Lee
- School of Chemistry and Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Republic of Ireland.
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4
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Rampini S, Li P, Gandhi D, Mutas M, Ran YF, Carr M, Lee GU. Design of micromagnetic arrays for on-chip separation of superparamagnetic bead aggregates and detection of a model protein and double-stranded DNA analytes. Sci Rep 2021; 11:5302. [PMID: 33674645 PMCID: PMC7935980 DOI: 10.1038/s41598-021-84395-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 02/10/2021] [Indexed: 01/17/2023] Open
Abstract
Magnetically actuated lab-on-a-chip (LOC) technologies have enabled rapid, highly efficient separation of specific biomarkers and cells from complex biological samples. Nonlinear magnetophoresis (NLM) is a technique that uses a microfabricated magnet array (MMA) and a time varying external magnetic field to precisely control the transport of superparamagnetic (SPM) beads on the surface of a chip based on their size and magnetization. We analyze the transport and separation behavior of SPM monomers and dimers on four MMA geometries, i.e., circular, triangular, square and rectangular shaped micromagnets, across a range of external magnetic field rotation frequencies. The measured critical frequency of the SPM beads on an MMA, i.e., the velocity for which the hydrodynamic drag on a bead exceeds the magnetic force, is closely related to the local magnetic flux density landscape on a micromagnet in the presence of an external magnetic field. A set of design criteria has been established for the optimization of MMAs for NLM separation, with particular focus on the shape of the micromagnets forming the array. The square MMA was used to detect a model protein biomarker and gene fragment based on a magnetic bead assembly (MBA) assay. This assay uses ligand functionalized SPM beads to capture and directly detect an analyte through the formation of SPM bead aggregates. These beads aggregates were detected through NLM separation and microscopic analysis resulting in a highly sensitive assay that did not use carrier fluid.
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Affiliation(s)
- Stefano Rampini
- School of Chemistry, University College Dublin, Belfield, Dublin, Ireland
| | - Peng Li
- School of Chemistry, University College Dublin, Belfield, Dublin, Ireland
| | - Dhruv Gandhi
- School of Chemistry, University College Dublin, Belfield, Dublin, Ireland
| | - Marina Mutas
- School of Chemistry, University College Dublin, Belfield, Dublin, Ireland
| | - Ying Fen Ran
- School of Chemistry, University College Dublin, Belfield, Dublin, Ireland
| | - Michael Carr
- National Virus Reference Laboratory, University College Dublin, Belfield, Dublin, Ireland.,Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Kita-ku, Sapporo, Japan
| | - Gil U Lee
- School of Chemistry, University College Dublin, Belfield, Dublin, Ireland. .,Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland.
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5
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Gandhi D, Li P, Rampini S, Parent C, Lee GU. Optical detection of the magnetophoretic transport of superparamagnetic beads on a micromagnetic array. Sci Rep 2020; 10:12876. [PMID: 32733006 PMCID: PMC7392889 DOI: 10.1038/s41598-020-69757-7] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 07/13/2020] [Indexed: 11/09/2022] Open
Abstract
Micromagnetic arrays (MMAs) have proven to be powerful tools for controlling the transport and separation of bioanalytes, i.e., they allow bioanalyte-superparamagnetic (SPM) bead complexes of specific size and magnetization to be moved in a synchronized manner that is precisely controlled with the orientation of an external magnetic field. This article presents a laser-photodetector system for the simple detection of individual SPM beads moving on a specific region of an MMA. This system detects the SPM beads through the change in intensity of reflective light as they move from the highly reflective micromagnetics to the supporting substrate. We demonstrate that this opti-MMA system allowed the size, number, and magnetic and optical properties of the SPM beads to be rapidly determined for regions > 49 µm2 in size. The response of the opti-MMA system was characterized in several optical configurations to develop a theoretical description of its sensitivity and dynamic range. The speed, low-cost, and sensitivity of this system promises to allow MMAs to be readily applied in in vitro diagnostics and biosensing.
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Affiliation(s)
- Dhruv Gandhi
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
| | - Peng Li
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Stefano Rampini
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
| | - Charlotte Parent
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
| | - Gil U Lee
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland.
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6
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Chang WS, Li P, Kakade S, Xiong Y, Shang H, Zhang Y, Lee GU. Rapid and sensitive detection of cardiac troponin I using a force enhanced immunoassay with nanoporous membrane. Nanoscale 2020; 12:12568-12577. [PMID: 32500903 DOI: 10.1039/d0nr02234a] [Citation(s) in RCA: 3] [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: 06/11/2023]
Abstract
There is a need for point of care diagnostic technologies that are rapid, sensitive, easy to use, and relatively inexpensive. In this article we describe an assay that uses an antibody functionalized nanoporous membrane and superparamagnetic beads to capture and detect human cardiac troponin I (cTnI), which is an important biomarker for acute myocardial infarction (AMI). The membrane assisted force differentiation assay (mFDA) is capable of detecting cTnI at a sensitivity of 0.1 pg ml-1 in 15% serum in less than 16 minutes, which is a significant improvement in performance over conventional lateral flow immuosorbant assays. The speed of this assay results from the rapid concentration of cTnI on the surface of the nanoporous membrane and the use of the magnetic beads to react with the analyte, which rapidly react with the immobilized cTnI. The increased sensitivity of assay results from the use of magnetically controlled forces that reduce the nonspecific background and modify both the on-rate and off-rate. We believe that the improved performance and ease of application of the mFDA will make it useful in the early identification of AMI as well as other diseases based on the detection of 1 pg ml-1 variations in the concentrations cTnI in blood.
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Affiliation(s)
- Won-Suk Chang
- Schools of Chemical and Biomedical Engineering, Forney Hall, Purdue University, West Lafayette, IN 47907, USA.
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7
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Li P, Gandhi D, Mutas M, Ran YF, Carr M, Rampini S, Hall W, Lee GU. Direct identification of the herpes simplex virus UL27 gene through single particle manipulation and optical detection using a micromagnetic array. Nanoscale 2020; 12:3482-3490. [PMID: 31971211 DOI: 10.1039/c9nr10362g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Magnetophoretic lab on a chip technologies are rapidly evolving into integrated systems for the identification of biomarkers and cells with ultra-high sensitivity. We demonstrate the highly efficient detection of the Human herpes simplex virus type 1 (HSV) UL27 gene through the programmed assembly of superparamagnetic (SPM) nanoparticles based on oligonucleotide hybridization. The state of assembly of the SPM nanoparticles was determined by optical signature of the synchronized motion on the beads on a micromagnetic array (MMA). This technique has been used to identify <200 copies of the HSV UL27 gene without amplification in less than 20 minutes. The MAA can also be used to separate gene-SPM bead aggregates from millions of unreacted SPM beads based on nonlinear magnetophoresis (NLM). The MMA-optical detection system promises to enable highly sensitive, nucleic acid analysis to be performed without amplification and with the consumption of minimal amounts of reagent.
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Affiliation(s)
- Peng Li
- School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Dhruv Gandhi
- School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Marina Mutas
- School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Yin-Fen Ran
- School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Michael Carr
- UCD National Virus Reference Laboratory, University College Dublin, Belfield, Dublin 4, Ireland and Global Station for Zoonosis Control, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo 001-0020, Japan
| | - Stefano Rampini
- School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland.
| | - William Hall
- UCD National Virus Reference Laboratory, University College Dublin, Belfield, Dublin 4, Ireland
| | - Gil U Lee
- School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland.
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8
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Lesniak A, Kilinc D, Blasiak A, Galea G, Simpson JC, Lee GU. Rapid Growth Cone Uptake and Dynein-Mediated Axonal Retrograde Transport of Negatively Charged Nanoparticles in Neurons Is Dependent on Size and Cell Type. Small 2019; 15:e1803758. [PMID: 30565853 DOI: 10.1002/smll.201803758] [Citation(s) in RCA: 5] [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] [Received: 09/12/2018] [Revised: 10/20/2018] [Indexed: 06/09/2023]
Abstract
Nanoparticles (NPs) are now used in numerous technologies and serve as carriers for several new classes of therapeutics. Studies of the distribution of NPs in vivo demonstrate that they can be transported through biological barriers and are concentrated in specific tissues. Here, transport behavior, and final destination of polystyrene NPs are reported in primary mouse cortical neurons and SH-SY5Y cells, cultured in two-compartmental microfluidic devices. In both cell types, negative polystyrene NPs (PS(-)) smaller than 100 nm are taken up by the axons, undergo axonal retrograde transport, and accumulate in the somata. Examination of NP transport reveals different transport mechanisms depending on the cell type, particle charge, and particle internalization by the lysosomes. In cortical neurons, PS(-) inside lysosomes and 40 nm positive polystyrene NPs undergo slow axonal transport, whereas PS(-) outside lysosomes undergo fast axonal transport. Inhibition of dynein in cortical neurons decreases the transport velocity and cause a dose-dependent reduction in the number of accumulated PS(-), suggesting that the fast axonal transport is dynein mediated. These results show that the axonal retrograde transport of NPs depends on the endosomal pathway taken and establishes a means for screening nanoparticle-based therapeutics for diseases that involve neurons.
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Affiliation(s)
- Anna Lesniak
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
| | - Devrim Kilinc
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Agata Blasiak
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
| | - George Galea
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
- School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Jeremy C Simpson
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
- School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Gil U Lee
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
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9
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Lyden A, Lombardi L, Sire W, Li P, Simpson JC, Butler G, Lee GU. Characterization of carboxylate nanoparticle adhesion with the fungal pathogen Candida albicans. Nanoscale 2017; 9:15911-15922. [PMID: 29019498 DOI: 10.1039/c7nr04724j] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Candida albicans is the lead fungal pathogen of nosocomial bloodstream infections worldwide and has mortality rates of 43%. Nanoparticles have been identified as a means to improve medical outcomes for Candida infections, enabling sample concentration, serving as contrast agents for in vivo imaging, and delivering therapeutics. However, little is known about how nanoparticles interact with the fungal cell wall. In this report we used laser scanning confocal microscopy to examine the interaction of fluorescent polystyrene nanoparticles of specific surface chemistry and diameter with C. albicans and mutant strains deficient in various C. albicans surface proteins. Carboxylate-functionalized nanoparticles adsorbed mainly to the hyphae of wild-type C. albicans. The dissociative binding constant of the nanoparticles was ∼150, ∼30 and ∼2.5 pM for 40, 100 nm and 200 nm diameter particles, respectively. A significant reduction in particle binding was observed with a Δals3 strain compared to wild-type strains, identifying the Als3 adhesin as the main mediator of this nanoparticle adhesion. In the absence of Als3, nanoparticles bound to germ tubes and yeast cells in a pattern resembling the localization of Als1, indicating Als1 also plays a role. Nanoparticle surface charge was shown to influence binding - positively charged amine-functionalized nanoparticles failed to bind to the hyphal cell wall. Binding of carboxylate-functionalized nanoparticles was observed in the presence of serum, though interactions were reduced. These observations show that Als3 and Als1 are important targets for nanoparticle-mediated diagnostics and therapeutics, and provide direction for optimal diameter and surface characteristics of nanoparticles that bind to the fungal cell wall.
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Affiliation(s)
- Amy Lyden
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland.
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10
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Blasiak A, Kilinc D, Lee GU. Neuronal Cell Bodies Remotely Regulate Axonal Growth Response to Localized Netrin-1 Treatment via Second Messenger and DCC Dynamics. Front Cell Neurosci 2017; 10:298. [PMID: 28105005 PMCID: PMC5214882 DOI: 10.3389/fncel.2016.00298] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [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: 09/29/2016] [Accepted: 12/16/2016] [Indexed: 12/15/2022] Open
Abstract
Netrin-1 modulates axonal growth direction and speed. Its best characterized receptor, Deleted in Colorectal Cancer (DCC), is localized to growth cones, but also observed in the cell bodies. We hypothesized that cell bodies sense Netrin-1 and contribute to axon growth rate modulation, mediated by the second messenger system. We cultured mouse cortical neurons in microfluidic devices to isolate distal axon and cell body microenvironments. Compared to isolated axonal treatment, global Netrin-1 treatment decreased the axon elongation rate and affected the dynamics of total and membranous DCC, calcium, and cyclic nucleotides. Signals induced by locally applied Netrin-1 propagated in both anterograde and retrograde directions, demonstrated by the long-range increase in DCC and by the increased frequency of calcium transients in cell bodies, evoked by axonal Netrin-1. Blocking the calcium efflux from endoplasmic reticulum suppressed the membranous DCC response. Our findings support the notion that neurons sense Netrin-1 along their entire lengths in making axonal growth decisions.
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Affiliation(s)
- Agata Blasiak
- Bionanosciences Group, School of Chemistry, University College Dublin Dublin, Ireland
| | - Devrim Kilinc
- Bionanosciences Group, School of Chemistry, University College DublinDublin, Ireland; UCD Conway Institute of Biomedical and Biomolecular Research, University College DublinDublin, Ireland
| | - Gil U Lee
- Bionanosciences Group, School of Chemistry, University College DublinDublin, Ireland; UCD Conway Institute of Biomedical and Biomolecular Research, University College DublinDublin, Ireland
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11
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Rampini S, Li P, Lee GU. Micromagnet arrays enable precise manipulation of individual biological analyte-superparamagnetic bead complexes for separation and sensing. Lab Chip 2016; 16:3645-63. [PMID: 27542153 DOI: 10.1039/c6lc00707d] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
In this article, we review lab on a chip (LOC) devices that have been developed for processing magnetically labelled biological analytes, e.g., proteins, nucleic acids, viruses and cells, based on micromagnetic structures and a time-varying magnetic field. We describe the methods that have been developed for fabricating micromagnetic arrays and the bioprocessing operations that have been demonstrated using superparamagnetic (SPM) beads, i.e., programmed transport, switching, separation of specific analytes, and pumping and mixing of fluids in microchannels. The primary advantage of micromagnet devices is that they make it possible to develop systems that control individual SPM beads, enabling high-efficiency separation and analysis. These devices do not require hydrodynamic control and lend themselves to parallel processing of large arrays of SPM beads with modest levels of power consumption. Micromagnet devices are well suited for bioanalytical applications that require high-resolution separation, e.g., detection of rare cell types such as circulating tumour cells, or biosensor applications that require multiple magnetic bioprocessing operations on a single chip.
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Affiliation(s)
- S Rampini
- School of Chemistry and Chemical Biology, UCD, Dublin, Ireland.
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12
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Kilinc D, Dennis CL, Lee GU. Bio-Nano-Magnetic Materials for Localized Mechanochemical Stimulation of Cell Growth and Death. Adv Mater 2016; 28:5672-80. [PMID: 26780501 PMCID: PMC5536250 DOI: 10.1002/adma.201504845] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [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: 10/01/2015] [Revised: 11/12/2015] [Indexed: 05/16/2023]
Abstract
Magnetic nanoparticles are promising new tools for therapeutic applications, such as magnetic nanoparticle hyperthermia therapy and targeted drug delivery. Recent in vitro studies have demonstrated that a force application with magnetic tweezers can also affect cell fate, suggesting a therapeutic potential for magnetically modulated mechanical stimulation. The magnetic properties of nanoparticles that induce physical responses and the subtle responses that result from mechanically induced membrane damage and/or intracellular signaling are evaluated. Magnetic particles with various physical, geometric, and magnetic properties and specific functionalization can now be used to apply mechanical force to specific regions of cells, which permit the modulation of cellular behavior through the use of spatially and time controlled magnetic fields. On one hand, mechanochemical stimulation has been used to direct the outgrowth on neuronal growth cones, indicating a therapeutic potential for neural repair. On the other hand, it has been used to kill cancer cells that preferentially express specific receptors. Advances made in the synthesis and characterization of magnetic nanomaterials and a better understanding of cellular mechanotransduction mechanisms may support the translation of mechanochemical stimulation into the clinic as an emerging therapeutic approach.
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Affiliation(s)
- Devrim Kilinc
- Bionanosciences Lab, School of Chemistry and Chemical Biology, UCD
Conway Institute of Biomolecular and Biomedical Research, University College Dublin,
Belfield, Dublin 4, Ireland
| | - Cindi L. Dennis
- Material Measurement Laboratory, National Institute of Standards and
Technology, 100 Bureau Drive, Gaithersburg, MD 20899–8552, USA
| | - Gil U. Lee
- Bionanosciences Lab, School of Chemistry and Chemical Biology, UCD
Conway Institute of Biomolecular and Biomedical Research, University College Dublin,
Belfield, Dublin 4, Ireland
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13
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Kelly CM, Muzard J, Brooks BR, Lee GU, Buchete NV. Structure and dynamics of the fibronectin-III domains of Aplysia californica cell adhesion molecules. Phys Chem Chem Phys 2016; 17:9634-43. [PMID: 25729787 DOI: 10.1039/c4cp05307a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Due to their homophilic and heterophilic binding properties, cell adhesion molecules (CAMs) such as integrin, cadherin and the immunoglobulin superfamily CAMs are of primary importance in cell-cell and cell-substrate interactions, signalling pathways and other crucial biological processes. We study the molecular structures and conformational dynamics of the two fibronectin type III (Fn-III) extracellular domains of the Aplysia californica CAM (apCAM) protein, by constructing and probing an atomically-detailed structural model based on apCAM's homology with other CAMs. The stability and dynamic properties of the Fn-III domains, individually and in tandem, are probed and analysed using all-atom explicit-solvent molecular dynamics (MD) simulations and normal mode analysis of their corresponding elastic network models. The refined structural model of the Fn-III tandem of apCAM reveals a specific pattern of amino acid interactions that controls the stability of the β-sheet rich structure and could affect apCAM's response to physical or chemical changes of its environment. It also exposes the important role of several specific charged residues in modulating the structural properties of the linker segment connecting the two Fn-III domains, as well as of the inter-domain interface.
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Affiliation(s)
- Catherine M Kelly
- School of Physics, University College Dublin, Belfield, Dublin 4, Ireland.
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14
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Kilinc D, Schwab J, Rampini S, Ikpekha OW, Thampi A, Blasiak A, Li P, Schwamborn R, Kolch W, Matallanas D, Lee GU. A microfluidic dual gradient generator for conducting cell-based drug combination assays. Integr Biol (Camb) 2016; 8:39-49. [DOI: 10.1039/c5ib00209e] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
We present a microfluidic gradient generator that exposes cultured cells to orthogonally-aligned linear concentration gradients of two molecules. Live-cell assays quantifying apoptotic signaling and cell motility are provided as proof-of-concept.
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Affiliation(s)
- Devrim Kilinc
- School of Chemistry and Chemical Biology
- University College Dublin
- Dublin 4
- Ireland
- UCD Conway Institute
| | - Jefrem Schwab
- School of Chemistry and Chemical Biology
- University College Dublin
- Dublin 4
- Ireland
| | - Stefano Rampini
- School of Chemistry and Chemical Biology
- University College Dublin
- Dublin 4
- Ireland
| | - Oshoke W. Ikpekha
- School of Chemistry and Chemical Biology
- University College Dublin
- Dublin 4
- Ireland
| | - Ashwin Thampi
- School of Chemistry and Chemical Biology
- University College Dublin
- Dublin 4
- Ireland
| | - Agata Blasiak
- School of Chemistry and Chemical Biology
- University College Dublin
- Dublin 4
- Ireland
| | - Peng Li
- School of Chemistry and Chemical Biology
- University College Dublin
- Dublin 4
- Ireland
| | | | - Walter Kolch
- UCD Conway Institute
- Dublin 4
- Ireland
- Systems Biology Ireland
- UCD
| | | | - Gil U. Lee
- School of Chemistry and Chemical Biology
- University College Dublin
- Dublin 4
- Ireland
- UCD Conway Institute
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15
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Blasiak A, Lee GU, Kilinc D. Neuron Subpopulations with Different Elongation Rates and DCC Dynamics Exhibit Distinct Responses to Isolated Netrin-1 Treatment. ACS Chem Neurosci 2015; 6:1578-90. [PMID: 26190161 DOI: 10.1021/acschemneuro.5b00142] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Correct wiring of the nervous system requires guidance cues, diffusible or substrate-bound proteins that steer elongating axons to their target tissues. Netrin-1, the best characterized member of the Netrins family of guidance molecules, is known to induce axon turning and modulate axon elongation rate; however, the factors regulating the axonal response to Netrin-1 are not fully understood. Using microfluidics, we treated fluidically isolated axons of mouse primary cortical neurons with Netrin-1 and characterized axon elongation rates, as well as the membrane localization of deleted in colorectal cancer (DCC), a well-established receptor of Netrin-1. The capacity to stimulate and observe a large number of individual axons allowed us to conduct distribution analyses, through which we identified two distinct neuron subpopulations based on different elongation behavior and different DCC membrane dynamics. Netrin-1 reduced the elongation rates in both subpopulations, where the effect was more pronounced in the slow growing subpopulation. Both the source of Ca(2+) influx and the basal cytosolic Ca(2+) levels regulated the effect of Netrin-1, for example, Ca(2+) efflux from the endoplasmic reticulum due to the activation of Ryanodine channels blocked Netrin-1-induced axon slowdown. Netrin-1 treatment resulted in a rapid membrane insertion of DCC, followed by a gradual internalization. DCC membrane dynamics were different in the central regions of the growth cones compared to filopodia and axon shafts, highlighting the temporal and spatial heterogeneity in the signaling events downstream of Netrin-1. Cumulatively, these results demonstrate the power of microfluidic compartmentalization and distribution analysis in describing the complex axonal Netrin-1 response.
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Affiliation(s)
- Agata Blasiak
- Bionanoscience Group, School
of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin
4, Ireland
| | - Gil U. Lee
- Bionanoscience Group, School
of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin
4, Ireland
| | - Devrim Kilinc
- Bionanoscience Group, School
of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin
4, Ireland
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16
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Rampini S, Kilinc D, Li P, Monteil C, Gandhi D, Lee GU. Micromagnet arrays for on-chip focusing, switching, and separation of superparamagnetic beads and single cells. Lab Chip 2015; 15:3370-3379. [PMID: 26160691 DOI: 10.1039/c5lc00581g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Nonlinear magnetophoresis (NLM) is a novel approach for on-chip transport and separation of superparamagnetic (SPM) beads, based on a travelling magnetic field wave generated by the combination of a micromagnet array (MMA) and an applied rotating magnetic field. Here, we present two novel MMA designs that allow SPM beads to be focused, sorted, and separated on-chip. Converging MMAs were used to rapidly collect the SPM beads from a large region of the chip and focus them into synchronised lines. We characterise the collection efficiency of the devices and demonstrate that they can facilitate on-chip analysis of populations of SPM beads using a single-point optical detector. The diverging MMAs were used to control the transport of the beads and to separate them based on their size. The separation efficiency of these devices was determined by the orientation of the magnetisation of the micromagnets relative to the external magnetic field and the size of the beads and relative to that of micromagnets. By controlling these parameters and the rotation of the external magnetic field we demonstrated the controlled transport of SPM bead-labelled single MDA-MB-231 cells. The use of these novel MMAs promises to allow magnetically-labelled cells to be efficiently isolated and then manipulated on-chip for analysis with high-resolution chemical and physical techniques.
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Affiliation(s)
- S Rampini
- Bionanoscience Group, School of Chemistry and Chemical Biology, UCD, Dublin, Ireland.
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17
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Kilinc D, Blasiak A, Lee GU. Microtechnologies for studying the role of mechanics in axon growth and guidance. Front Cell Neurosci 2015; 9:282. [PMID: 26283918 PMCID: PMC4515553 DOI: 10.3389/fncel.2015.00282] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [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: 06/01/2015] [Accepted: 07/10/2015] [Indexed: 12/18/2022] Open
Abstract
The guidance of axons to their proper targets is not only a crucial event in neurodevelopment, but also a potential therapeutic target for neural repair. Axon guidance is mediated by various chemo- and haptotactic cues, as well as the mechanical interactions between the cytoskeleton and the extracellular matrix (ECM). Axonal growth cones, dynamic ends of growing axons, convert external stimuli to biochemical signals, which, in turn, are translated into behavior, e.g., turning or retraction, via cytoskeleton-matrix linkages. Despite the inherent mechanical nature of the problem, the role of mechanics in axon guidance is poorly understood. Recent years has witnessed the application of a range of microtechnologies in neurobiology, from microfluidic circuits to single molecule force spectroscopy. In this mini-review, we describe microtechnologies geared towards dissecting the mechanical aspects of axon guidance, divided into three categories: controlling the growth cone microenvironment, stimulating growth cones with externally applied forces, and measuring forces exerted by the growth cones. A particular emphasis is given to those studies that combine multiple techniques, as dictated by the complexity of the problem.
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Affiliation(s)
- Devrim Kilinc
- Bionanosciences Group, School of Chemisty and Chemical Biology, University College Dublin Belfield, Dublin, Ireland
| | - Agata Blasiak
- Bionanosciences Group, School of Chemisty and Chemical Biology, University College Dublin Belfield, Dublin, Ireland
| | - Gil U Lee
- Bionanosciences Group, School of Chemisty and Chemical Biology, University College Dublin Belfield, Dublin, Ireland
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18
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Fields C, Li P, O'Mahony JJ, Lee GU. Advances in affinity ligand-functionalized nanomaterials for biomagnetic separation. Biotechnol Bioeng 2015; 113:11-25. [DOI: 10.1002/bit.25665] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 05/21/2015] [Accepted: 05/24/2015] [Indexed: 12/31/2022]
Affiliation(s)
- Conor Fields
- School of Chemistry and Chemical Biology; University College Dublin, Belfield, Dublin 4; Ireland
| | - Peng Li
- School of Chemistry and Chemical Biology; University College Dublin, Belfield, Dublin 4; Ireland
| | - James J. O'Mahony
- School of Chemistry and Chemical Biology; University College Dublin, Belfield, Dublin 4; Ireland
| | - Gil U. Lee
- School of Chemistry and Chemical Biology; University College Dublin, Belfield, Dublin 4; Ireland
- Conway Institute for Biomolecular and Biomedical Sciences; University College Dublin, Belfield, Dublin 4; Ireland
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19
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Kilinc D, Lesniak A, Rashdan SA, Gandhi D, Blasiak A, Fannin PC, von Kriegsheim A, Kolch W, Lee GU. Mechanochemical stimulation of MCF7 cells with rod-shaped Fe-Au Janus particles induces cell death through paradoxical hyperactivation of ERK. Adv Healthc Mater 2015; 4:395-404. [PMID: 25296863 DOI: 10.1002/adhm.201400391] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [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: 07/09/2014] [Revised: 09/11/2014] [Indexed: 12/12/2022]
Abstract
Multifunctional nanoparticles that actively target-specific tissues are studied for cancer diagnosis and treatment. Magnetically and optically active particles are of particular interest because they enable multiple imaging modalities and physically modulated therapies, such as magnetic hyperthermia. Fe-Au nanorods are synthesized that have a long iron segment, coated with polyethylene glycol, and a short gold tip functionalized with heregulin (HRG), a known ligand of ErbB family of receptors. HRG-nanorods preferentially target MCF7 cells relative to MDA-MB-231 cells, as demonstrated in a novel microfluidics device. Targeting rates of these classical breast cancer cells correlate with their differential expression of ErbB2/3 receptors. HRG-nanorod binding stimulates the extracellular signal-regulated kinase 1/2 (ERK) phosphorylation in MCF7 cells. The increase in ERK phosphorylation is linked to "active zones," dynamic regions in the cell periphery, which exhibit higher rates of particle binding than the rest of the cell. Periodically stretching cells using magnetic tweezers further activates ERK, which leads to cell death in cells co-treated with B-Raf inhibitors, through ERK hyperactivation. Although to a lesser extent, cell death is also achieved through magnetic hyperthermia. These results demonstrate nanoscale targeting and localized mechanochemical treatment of specific cancer cell lines based on their receptor expression using multifunctional nanoparticles.
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Affiliation(s)
- Devrim Kilinc
- UCD Nanomedicine Centre; School of Chemistry and Chemical Biology; University College Dublin; Belfield Dublin 4 Ireland
| | - Anna Lesniak
- UCD Nanomedicine Centre; School of Chemistry and Chemical Biology; University College Dublin; Belfield Dublin 4 Ireland
| | - Suad A. Rashdan
- UCD Nanomedicine Centre; School of Chemistry and Chemical Biology; University College Dublin; Belfield Dublin 4 Ireland
- Department of Chemistry; University of Bahrain; P.O. Box: 32038 Sakheer Kingdom of Bahrain
| | - Dhruv Gandhi
- UCD Nanomedicine Centre; School of Chemistry and Chemical Biology; University College Dublin; Belfield Dublin 4 Ireland
| | - Agata Blasiak
- UCD Nanomedicine Centre; School of Chemistry and Chemical Biology; University College Dublin; Belfield Dublin 4 Ireland
| | - Paul C. Fannin
- Department of Electronic and Electrical Engineering; Trinity College Dublin; Dublin 2 Ireland
| | - Alex von Kriegsheim
- Systems Biology Ireland; UCD; Belfield Dublin 4 Ireland
- UCD Conway Institute; Belfield Dublin 4 Ireland
- School of Medicine and Medical Science; UCD; Belfield Dublin 4 Ireland
| | - Walter Kolch
- Systems Biology Ireland; UCD; Belfield Dublin 4 Ireland
- UCD Conway Institute; Belfield Dublin 4 Ireland
- School of Medicine and Medical Science; UCD; Belfield Dublin 4 Ireland
| | - Gil U. Lee
- UCD Nanomedicine Centre; School of Chemistry and Chemical Biology; University College Dublin; Belfield Dublin 4 Ireland
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20
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Kilinc D, Blasiak A, O'Mahony JJ, Lee GU. Low piconewton towing of CNS axons against diffusing and surface-bound repellents requires the inhibition of motor protein-associated pathways. Sci Rep 2014; 4:7128. [PMID: 25417891 PMCID: PMC4241520 DOI: 10.1038/srep07128] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 11/03/2014] [Indexed: 12/24/2022] Open
Abstract
Growth cones, dynamic structures at axon tips, integrate chemical and physical stimuli and translate them into coordinated axon behaviour, e.g., elongation or turning. External force application to growth cones directs and enhances axon elongation in vitro; however, direct mechanical stimulation is rarely combined with chemotactic stimulation. We describe a microfluidic device that exposes isolated cortical axons to gradients of diffusing and substrate-bound molecules, and permits the simultaneous application of piconewton (pN) forces to multiple individual growth cones via magnetic tweezers. Axons treated with Y-27632, a RhoA kinase inhibitor, were successfully towed against Semaphorin 3A gradients, which repel untreated axons, with less than 12 pN acting on a small number of neural cell adhesion molecules. Treatment with Y-27632 or monastrol, a kinesin-5 inhibitor, promoted axon towing on substrates coated with chondroitin sulfate proteoglycans, potent axon repellents. Thus, modulating key molecular pathways that regulate contractile stress generation in axons counteracts the effects of repellent molecules and promotes tension-induced growth. The demonstration of parallel towing of axons towards inhibitory environments with minute forces suggests that mechanochemical stimulation may be a promising therapeutic approach for the repair of the damaged central nervous system, where regenerating axons face repellent factors over-expressed in the glial scar.
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Affiliation(s)
- Devrim Kilinc
- UCD Nanomedicine Centre, School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Agata Blasiak
- UCD Nanomedicine Centre, School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - James J O'Mahony
- UCD Nanomedicine Centre, School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Gil U Lee
- UCD Nanomedicine Centre, School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
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21
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Abstract
Magnetic tweezers (MTW) enable highly accurate forces to be transduced to molecules to study mechanotransduction at the molecular or cellular level. We review recent MTW studies in single molecule and cell biophysics that demonstrate the flexibility of this technique. We also discuss technical advances in the method on several fronts, i.e., from novel approaches for the measurement of torque to multiplexed biophysical assays. Finally, we describe multi-component nanorods with enhanced optical and magnetic properties and discuss their potential as future MTW probes.
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Affiliation(s)
- Devrim Kilinc
- UCD Nanomedicine Centre, School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland.
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22
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Ran YF, Fields C, Muzard J, Liauchuk V, Carr M, Hall W, Lee GU. Rapid, highly sensitive detection of herpes simplex virus-1 using multiple antigenic peptide-coated superparamagnetic beads. Analyst 2014; 139:6126-34. [DOI: 10.1039/c4an00774c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We demonstrate a label free assay employing scattering to determine the aggregation state of peptide-functionalized superparamagnetic beads. HSV-1 virus at 200 virus particles per mL was detected in 30 min, demonstrating potential use in point of care testing.
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Affiliation(s)
- Ying-Fen Ran
- Conway Institute for Biomolecular and Biomedical Science
- School of Chemistry and Chemical Biology
- University College Dublin
- Dublin 4, Ireland
| | - Conor Fields
- Conway Institute for Biomolecular and Biomedical Science
- School of Chemistry and Chemical Biology
- University College Dublin
- Dublin 4, Ireland
| | - Julien Muzard
- Conway Institute for Biomolecular and Biomedical Science
- School of Chemistry and Chemical Biology
- University College Dublin
- Dublin 4, Ireland
| | - Viktoryia Liauchuk
- Conway Institute for Biomolecular and Biomedical Science
- School of Chemistry and Chemical Biology
- University College Dublin
- Dublin 4, Ireland
| | - Michael Carr
- Centre for Research on Infectious Diseases
- School of Medicine
- University College Dublin
- Dublin 4, Ireland
| | - William Hall
- Centre for Research on Infectious Diseases
- School of Medicine
- University College Dublin
- Dublin 4, Ireland
| | - Gil U. Lee
- Conway Institute for Biomolecular and Biomedical Science
- School of Chemistry and Chemical Biology
- University College Dublin
- Dublin 4, Ireland
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23
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Stoeckli ET, Kilinc D, Kunz B, Kunz S, Lee GU, Martines E, Rader C, Suter D. Analysis of cell-cell contact mediated by Ig superfamily cell adhesion molecules. Curr Protoc Cell Biol 2013; 61:9.5.1-9.5.85. [PMID: 24510806 DOI: 10.1002/0471143030.cb0905s61] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Cell-cell adhesion is a fundamental requirement for all multicellular organisms. The calcium-independent cell adhesion molecules of the immunoglobulin superfamily (IgSF-CAMs) represent a major subgroup. They consist of immunoglobulin folds alone or in combination with other protein modules, often fibronectin type-III folds. More than 100 IgSF-CAMs have been identified in vertebrates and invertebrates. Most of the IgSF-CAMs are cell surface molecules that are membrane-anchored either by a single transmembrane segment or by a glycosylphosphatidylinositol (GPI) anchor. Some of the IgSF-CAMs also occur in soluble form, e.g., in the cerebrospinal fluid or in the vitreous fluid of the eye, due to naturally occurring cleavage of the GPI anchor or the membrane-proximal peptide segment. Some IgSF-CAMs, such as NCAM, occur in various forms that are generated by alternative splicing. This unit contains a series of protocols that have been used to study the function of IgSF-CAMs in vitro and in vivo.
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Affiliation(s)
- Esther T Stoeckli
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Devrim Kilinc
- School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin, Ireland
| | - Beat Kunz
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Stefan Kunz
- Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | - Gil U Lee
- School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin, Ireland
| | - Elena Martines
- Nanomedicine Centre, School of Chemistry and Chemical Biology, University College Dublin, Dublin, Ireland
| | - Christoph Rader
- Department of Cancer Biology, Scripps Florida, Jupiter, Florida
| | - Daniel Suter
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana
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24
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Abstract
Magnetic separation provides a rapid and efficient means of isolating biomaterials from complex mixtures based on their adsorption on superparamagnetic (SPM) beads. Flow enhanced non-linear magnetophoresis (FNLM) is a high-resolution mode of separation in which hydrodynamic and magnetic fields are controlled with micron resolution to isolate SPM beads with specific physical properties. In this article we demonstrate that a change in the critical frequency of FNLM can be used to identify beads with magnetic susceptibilities between 0.01 and 1.0 with a sensitivity of 0.01 Hz(-1). We derived an analytical expression for the critical frequency that explicitly incorporates the magnetic and non-magnetic composition of a complex to be separated. This expression was then applied to two cases involving the detection and separation of biological targets. This study defines the operating principles of FNLM and highlights the potential for using this technique for multiplexing diagnostic assays and isolating rare cell types.
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Affiliation(s)
- Peng Li
- Centre for Nanomedicine, School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Dublin, Ireland.
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25
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26
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Fields C, O'Connell D, Xiao S, Lee GU, Billiald P, Muzard J. Creation of recombinant antigen-binding molecules derived from hybridomas secreting specific antibodies. Nat Protoc 2013; 8:1125-48. [DOI: 10.1038/nprot.2013.057] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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27
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Kilinc D, Blasiak A, O'Mahony JJ, Suter DM, Lee GU. Magnetic tweezers-based force clamp reveals mechanically distinct apCAM domain interactions. Biophys J 2013; 103:1120-9. [PMID: 22995484 DOI: 10.1016/j.bpj.2012.08.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Revised: 08/03/2012] [Accepted: 08/08/2012] [Indexed: 11/25/2022] Open
Abstract
Cell adhesion molecules of the immunoglobulin superfamily (IgCAMs) play a crucial role in cell-cell interactions during nervous system development and function. The Aplysia CAM (apCAM), an invertebrate IgCAM, shares structural and functional similarities with vertebrate NCAM and therefore has been considered as the Aplysia homolog of NCAM. Despite these similarities, the binding properties of apCAM have not been investigated thus far. Using magnetic tweezers, we applied physiologically relevant, constant forces to apCAM-coated magnetic particles interacting with apCAM-coated model surfaces and characterized the kinetics of bond rupture. The average bond lifetime decreased with increasing external force, as predicted by theoretical considerations. Mathematical simulations suggest that the apCAM homophilic interaction is mediated by two distinct bonds, one involving all five immunoglobulin (Ig)-like domains in an antiparallel alignment and the other involving only two Ig domains. In summary, this study provides biophysical evidence that apCAM undergoes homophilic interactions, and that magnetic tweezers-based, force-clamp measurements provide a rapid and reliable method for characterizing relatively weak CAM interactions.
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Affiliation(s)
- Devrim Kilinc
- School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin, Ireland
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28
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Zhang Y, Ashall B, Doyle G, Zerulla D, Lee GU. Highly ordered Fe-Au heterostructured nanorod arrays and their exceptional near-infrared plasmonic signature. Langmuir 2012; 28:17101-17107. [PMID: 23101940 DOI: 10.1021/la302290v] [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] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The potential of highly ordered array nanostructures in sensing applications is well recognized, particularly with the ability to define the structural composition and arrangement of the individual nanorods accurately. The use of heterogeneous nanostructures generates an additional degree of freedom, which can be used to tailor the optical response of such arrays. In this article, we report on the fabrication and characterization of well-defined Fe-Au bisegmented nanorod arrays in a repeating hexagonal arrangement. Through an asymmetric etching method, free-standing Fe-Au nanorod arrays on a gold-coated substrate were produced with an inter-rod spacing of 26 nm. This separation distance renders the array capable of sustaining resonant electromagnetic wave coupling between individual rods. Owing to this coupling, the subwavelength arrangement, and the structural heterogeneity, the nanorod arrays exhibit unique plasmonic responses in the near-infrared (NIR) range. Enhanced sensitivity in this spectral region has not been identified for gold-only nanorods of equivalent dimensions. The NIR response offers confirmation of the potential of these highly ordered, high-density arrays for biomedical relevant applications, such as subcutaneous spectroscopy and biosensing.
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Affiliation(s)
- Yong Zhang
- School of Chemistry and Chemical Biology, University College Dublin, Dublin 4, Ireland
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29
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Fields C, Mallee P, Muzard J, Lee GU. Isolation of Bowman-Birk-Inhibitor from soybean extracts using novel peptide probes and high gradient magnetic separation. Food Chem 2012; 134:1831-8. [PMID: 23442627 DOI: 10.1016/j.foodchem.2012.03.085] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 02/27/2012] [Accepted: 03/21/2012] [Indexed: 11/19/2022]
Abstract
Soybean proteins offer exceptional promise in the area of cancer prevention and treatment. Specifically, Bowman-Birk Inhibitor (BBI) has the ability to suppress carcinogenesis in vivo, which has been attributed to BBI's inhibition of serine protease (trypsin and chymotrypsin) activity. The lack of molecular probes for the isolation of this protein has made it difficult to work with, limiting its progress as a significant candidate in the treatment of cancer. This study has successfully identified a set of novel synthetic peptides targeting the BBI, and has demonstrated the ability to bind BBI in vitro. One of those probes has been covalently immobilised on superparamagnetic microbeads to allow the isolation of BBI from soy whey mixtures in a single step. Our ultimate goal is the use of the described synthetic probe to facilitate the isolation of this potentially therapeutic protein for low cost, scalable analysis and production of BBI.
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Affiliation(s)
- Conor Fields
- Nanomedicine Centre, School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
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30
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Muzard J, Platt M, Lee GU. M13 bacteriophage-activated superparamagnetic beads for affinity separation. Small 2012; 8:2403-2411. [PMID: 22619210 DOI: 10.1002/smll.201200099] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 03/13/2012] [Indexed: 06/01/2023]
Abstract
The growth of the biopharmaceutical industry has created a demand for new technologies for the purification of genetically engineered proteins.The efficiency of large-scale, high-gradient magnetic fishing could be improved if magnetic particles offering higher binding capacity and magnetization were available. This article describes several strategies for synthesizing microbeads that are composed of a M13 bacteriophage layer assembled on a superparamagnetic core. Chemical cross-linking of the pVIII proteins to a carboxyl-functionalized bead produces highly responsive superparamagnetic particles (SPM) with a side-on oriented, adherent virus monolayer. Also, the genetic manipulation of the pIII proteins with a His(6) peptide sequence allows reversible assembly of the bacteriophage on a nitrilotriacetic-acid-functionalized core in an end-on configuration. These phage-magnetic particles are successfully used to separate antibodies from high-protein concentration solutions in a single step with a >90% purity. The dense magnetic core of these particles makes them five times more responsive to magnetic fields than commercial materials composed of polymer-(iron oxide) composites and a monolayer of phage could produce a 1000 fold higher antibody binding capacity. These new bionanomaterials appear to be well-suited to large-scale high-gradient magnetic fishing separation and promise to be cost effective as a result of the self-assembling and self-replicating properties of genetically engineered M13 bacteriophage.
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Affiliation(s)
- Julien Muzard
- UCD Centre for Nanomedicine, School of Chemistry & Chemical Biology - University, College Dublin Belfield, Dublin 4, Ireland
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Platt M, Willmott GR, Lee GU. Resistive pulse sensing of analyte-induced multicomponent rod aggregation using tunable pores. Small 2012; 8:2436-44. [PMID: 22570187 DOI: 10.1002/smll.201200058] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 03/07/2012] [Indexed: 05/09/2023]
Abstract
Resistive pulse sensing is used to monitor individual and aggregated rod-shaped nanoparticles as they move through tunable pores in elastomeric membranes. By comparing particles of similar dimensions, it is demonstrated that the resistive pulse signal of a rod is fundamentally different from that of a sphere. Rods can be distinguished using two measurements: the blockade event magnitude (Δi(p) ), which reveals the particle's size, and the full width at half maximum (FWHM) duration, which relates to the particle's speed and length. While the observed Δi(p) values agree well with simulations, the measured FWHM times are much larger than expected. This increase in dwell time, caused by rods moving through the pore in various orientations, is not observed for spherical particles. These differences are exploited in a new agglutination assay using rod-shaped particles. By controlling the surface chemistry and location of the capture ligand, rods are made to form either long "end-on-end" or wide "side-on" aggregates upon the addition of an analyte. This observation will facilitate multiplexed detection in agglutination assays, as particles with a particular aspect ratio can be distinguished by two measurements. This is first demonstrated with a biotinylated target and avidin capture probe, followed by the detection of platelet-derived growth factor (PDGF-BB) using an aptamer capture probe, with limits of detection down to femtomolar levels.
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Affiliation(s)
- Mark Platt
- Centre for Nanomedicine, School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland.
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Muzard J, Fields C, O'Mahony JJ, Lee GU. Probing the soybean Bowman-Birk inhibitor using recombinant antibody fragments. J Agric Food Chem 2012; 60:6164-72. [PMID: 22642722 DOI: 10.1021/jf3004724] [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: 06/01/2023]
Abstract
The nutritional and health benefits of soy protein have been extensively studied over recent decades. The Bowman-Birk inhibitor (BBI), derived from soybeans, is a double-headed inhibitor of chymotrypsin and trypsin with anticarcinogenic and anti-inflammatory properties, which have been demonstrated in vitro and in vivo. However, the lack of analytical and purification methodologies complicates its potential for further functional and clinical investigations. This paper reports the construction of anti-BBI antibody fragments based on the principle of protein design. Recombinant antibody (scFv and diabody) molecules targeting soybean BBI were produced and characterized in vitro (K(D)~1.10(-9) M), and the antibody-binding site (epitope) was identified as part of the trypsin-specific reactive loop. Finally, an extremely fast purification strategy for BBI from soybean extracts, based on superparamagnetic particles coated with antibody fragments, was developed. To the best of the authors' knowledge, this is the first report on the design and characterization of recombinant anti-BBI antibodies and their potential application in soybean processing.
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Affiliation(s)
- Julien Muzard
- Bionanosciences, UCD Centre for Nanomedicine, School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland.
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Zhang Y, Wang Q, Ashall B, Zerulla D, Lee GU. Magnetic-plasmonic dual modulated FePt-Au ternary heterostructured nanorods as a promising nano-bioprobe. Adv Mater 2012; 24:2485-90. [PMID: 22488781 DOI: 10.1002/adma.201103991] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 01/24/2012] [Indexed: 05/21/2023]
Abstract
Ternary FePt-Au nanorods are synthesized as magnetic-plasmonic 1D nanostructures. Besides their widely tunable magnetic properties, their unique plasmonic response to the illumination polarization provides a powerful tool to optically image these sub-wavelength single nanorods. These nanoparticles also show the potential as a novel nano-bioprobe based on the demonstration of simultaneous magnetic manipulation and optical imaging of single particles inside live cells.
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Affiliation(s)
- Yong Zhang
- School of Chemistry and Chemical Biology, University College Dublin, Dublin 4, Ireland; School of Physics, Trinity College Dublin, Dublin 2, Ireland.
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Willmott GR, Platt M, Lee GU. Resistive pulse sensing of magnetic beads and supraparticle structures using tunable pores. Biomicrofluidics 2012; 6:14103-1410315. [PMID: 22662090 PMCID: PMC3365342 DOI: 10.1063/1.3673596] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Accepted: 12/09/2011] [Indexed: 05/14/2023]
Abstract
Tunable pores (TPs) have been used for resistive pulse sensing of 1 μm superparamagnetic beads, both dispersed and within a magnetic field. Upon application of this field, magnetic supraparticle structures (SPSs) were observed. Onset of aggregation was most effectively indicated by an increase in the mean event magnitude, with data collected using an automated thresholding method. Simulations enabled discrimination between resistive pulses caused by dimers and individual particles. Distinct but time-correlated peaks were often observed, suggesting that SPSs became separated in pressure-driven flow focused at the pore constriction. The distinct properties of magnetophoretic and pressure-driven transport mechanisms can explain variations in the event rate when particles move through an asymmetric pore in either direction, with or without a magnetic field applied. Use of TPs for resistive pulse sensing holds potential for efficient, versatile analysis and measurement of nano- and microparticles, while magnetic beads and particle aggregation play important roles in many prospective biosensing applications.
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Zhang Y, DaSilva M, Ashall B, Doyle G, Zerulla D, Sands TD, Lee GU. Magnetic manipulation and optical imaging of an active plasmonic single-particle Fe-Au nanorod. Langmuir 2011; 27:15292-15298. [PMID: 22046955 DOI: 10.1021/la203863p] [Citation(s) in RCA: 13] [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] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Superparamagnetic microbeads play an important role in a number of scientific and biotechnology applications including single-molecule force measurements, affinity separation, and in vivo and in vitro diagnostics. Magneto-optically active nanorods composed of single-crystalline Au and polycrystalline Fe segments were synthesized with diameters of 60 or 295 nm using templated electrodeposition. The Fe section was magnetically soft and had a saturation magnetization of approximately 200 emu/g, resulting in a 10-fold increase in magnetization relative to that iron oxide nanoparticles. The strong plasmonic response of the Au segment of the rod in both the longitudinal and transverse directions made it possible to detect the orientation of a single rod in a polarized light microscope with nanometer resolution. These nanorods provide significantly improved physical properties over iron oxide superparamagnetic beads, making it possible to simultaneously manipulate and monitor the orientation of biomolecules with well-defined forces at the nanometer scale.
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Affiliation(s)
- Yong Zhang
- School of Chemistry and Chemical Biology, University College Dublin, Dublin 4, Ireland
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36
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Abstract
A new mode of transport is described that was capable of high-resolution separation of superparamagnetic materials from complex mixtures based on their size. Laminar flow and a rotating external magnetic field were applied to superparamagnetic beads assembled on a semiperiodic micromagnet array. Beads at the edge of the micromagnet array oscillated in-phase with the external magnetic field with an amplitude that decreased with increasing frequency, ω, until they reached an immobilization frequency, ω(i), where the beads stopped moving. Laminar flow along the edge of the array could be tuned to sweep the beads for which ω < ω(i) downstream at a velocity that increased with size while leaving beads for which ω > ω(i) undisturbed. Flow-enhanced nonlinear magnetophoresis (F-NLM) promises to enable multiple superparamagnetc bead types to be used in the fractionation of cells and implementation of diagnostic assays.
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Affiliation(s)
- Peng Li
- School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
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37
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Xiong Y, Lee AC, Suter DM, Lee GU. Topography and nanomechanics of live neuronal growth cones analyzed by atomic force microscopy. Biophys J 2009; 96:5060-72. [PMID: 19527666 DOI: 10.1016/j.bpj.2009.03.032] [Citation(s) in RCA: 60] [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] [Received: 08/22/2008] [Revised: 03/01/2009] [Accepted: 03/26/2009] [Indexed: 10/20/2022] Open
Abstract
Neuronal growth cones are motile structures located at the end of axons that translate extracellular guidance information into directional movements. Despite the important role of growth cones in neuronal development and regeneration, relatively little is known about the topography and mechanical properties of distinct subcellular growth cone regions under live conditions. In this study, we used the AFM to study the P domain, T zone, and C domain of live Aplysia growth cones. The average height of these regions was calculated from contact mode AFM images to be 183 +/- 33, 690 +/- 274, and 1322 +/- 164 nm, respectively. These findings are consistent with data derived from dynamic mode images of live and contact mode images of fixed growth cones. Nano-indentation measurements indicate that the elastic moduli of the C domain and T zone ruffling region ranged between 3-7 and 7-23 kPa, respectively. The range of the measured elastic modulus of the P domain was 10-40 kPa. High resolution images of the P domain suggest its relatively high elastic modulus results from a dense meshwork of actin filaments in lamellipodia and from actin bundles in the filopodia. The increased mechanical stiffness of the P and T domains is likely important to support and transduce tension that develops during growth cone steering.
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Affiliation(s)
- Ying Xiong
- School of Chemical Engineering, Purdue University, West Lafayette, Indiana, USA
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38
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Abstract
A model analyte, the M13 virus, was detected through the change in the Brownian motion of a population of microparticles. Epi-fluorescence microscopy was used to simultaneously track antibody-coated and bare microparticles to unambiguously measure the diffusion coefficient and demonstrate multiplexed detection. The sensitivity of the diffusometry assay was high enough that individual virus-to-particle binding ratios could be detected. Analysis of the experimental errors indicated that the primary limitation in the sensitivity of this technique was the variation in the size of the population of microparticles. Analysis of the diffusion measurement results indicated that the change in the drag coefficient of the virus-particle assembly was not a simple sum of the drag coefficients of the individual components and the rate of particle-particle reaction was slower than would be predicted from the uncoupled particle hydrodynamics. The possibility of using diffusometry for sensing and proteomics applications is examined.
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Affiliation(s)
- Venu M Gorti
- School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, USA
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39
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Chang WS, Shang H, Perera RM, Lok SM, Sedlak D, Kuhn RJ, Lee GU. Rapid detection of dengue virus in serum using magnetic separation and fluorescence detection. Analyst 2008; 133:233-40. [DOI: 10.1039/b710997k] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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40
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Abstract
A new mode of magnetophoresis is described that is capable of separating micron-sized superparamagnetic beads from complex mixtures with high sensitivity to their size and magnetic moment. This separation technique employs a translating periodic potential energy landscape to transport magnetic beads horizontally across a substrate. The potential energy landscape is created by superimposing an external, rotating magnetic field on top of the local fixed magnetic field distribution near a periodic arrangement of micro-magnets. At low driving frequencies of the external field rotation, the beads become locked into the potential energy landscape and move at the same velocity as the traveling magnetic field wave. At frequencies above a critical threshold, defined by the bead's hydrodynamic drag and magnetic moment, the motion of a specific population of magnetic beads becomes uncoupled from the potential energy landscape and its magnetophoretic mobility is dramatically reduced. By exploiting this frequency dependence, highly efficient separation of magnetic beads has been achieved, based on fractional differences in bead diameter and/or their specific attachment to two microorganisms, i.e., B. globigii and S. cerevisiae.
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Affiliation(s)
- Benjamin B Yellen
- Duke University, Department of Mechanical Engineering and Materials Science, Durham, NC 27708, USA.
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41
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Kang E, Park JW, McClellan S, Kim JM, Holland D, Lee GU, Franses E, Park K, Thompson DH. Specific adsorption of histidine-tagged proteins on silica surfaces modified with Ni2+/NTA-derivatized poly(ethylene glycol). Langmuir 2007; 23:6281-8. [PMID: 17444666 PMCID: PMC2533260 DOI: 10.1021/la063719e] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Silica surfaces modified with nitrilotriacetic acid (NTA)-polyethylene glycol (PEG) derivatives were used to immobilize hexahistidine-tagged green fluorescent protein (His6-GFP), biotin/streptavidin-AlexaFluor555 (His6-biotin/SA-AF), and gramicidin A-containing vesicles (His6-gA). Three types of surface-reactive PEG derivatives-NTA-PEG3400-Si(OMe)3, NTA-PEG3400-vinylsulfone, and mPEG5000-Si(OMe)3 (control)-were grafted onto silica and tested for their ability to capture His6-tag species via His6/Ni2+/NTA chelation. The composition and thicknesses of the PEG-modified surfaces were characterized using X-ray photoelectron spectroscopy, contact angle, and ellipsometry. Protein capture efficiencies of the NTA-PEG-grafted surfaces were evaluated by measuring fluorescence intensities of these surfaces after exposure to His6-tag species. XPS and ellipsometry data indicate that surface adsorption occurs via specific interactions between the His6-tag and the Ni2+/NTA-PEG-grafted surface. Protein immobilization was most effective for NTA-PEG3400-Si(OMe)3-modified surfaces, with maximal areal densities achieved at 45 pmol/cm2 for His6-GFP and 95 fmol/cm2 for His6-biotin/SA-AF. Lipid vesicles containing His6-gA in a 1:375 gA/lipid ratio could also be immobilized on Ni2+/NTA-PEG3400-Si(OMe)3-modified surfaces at 0.5 mM total lipid. Our results suggest that NTA-PEG-Si(OMe)3 conjugates may be useful tools for immobilizing His6-tag proteins on solid surfaces to produce protein-functionalized surfaces.
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Affiliation(s)
- Eunah Kang
- School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907
| | - Jin-won Park
- School of Chemical Engineering, Purdue University, West Lafayette, IN 47907
| | - Scott McClellan
- School of Chemical Engineering, Purdue University, West Lafayette, IN 47907
| | - Jong-Mok Kim
- Department of Chemistry, Purdue University, West Lafayette, IN 47907
| | - David Holland
- Department of Chemistry, Purdue University, West Lafayette, IN 47907
| | - Gil U. Lee
- School of Chemical Engineering, Purdue University, West Lafayette, IN 47907
| | - Elias Franses
- School of Chemical Engineering, Purdue University, West Lafayette, IN 47907
| | - Kinam Park
- School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907
- Department of Pharmaceutics, Purdue University, West Lafayette, IN 47907
| | - David H. Thompson
- Department of Chemistry, Purdue University, West Lafayette, IN 47907
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Abstract
The bond lifetime-force behavior of the immunoglobulin G (IgG)-protein A interaction has been studied with magnetic tweezers to characterize the physical properties of the bond under nonequilibrium conditions. Super-paramagnetic microparticles were developed that have a high and uniform magnetization to simultaneously apply a piconewton-scale tensile force to many thousands of IgG-protein A bonds. A strong and a weak slip bond were detected with an effective bond length that is characteristic of short-range, stiff intermolecular interactions. These bonds are attributed to the interaction of protein A with the constant region (Fc) and heavy chain variable domain (VH) of IgG, respectively. The IgG-VH interaction appears to be one of the weakest specific molecular interactions that has been identified with a single molecule force measurement technique. This study demonstrates that magnetic tweezers can be used to rapidly characterize very weak biomolecular interactions as well as strong biomolecular interactions with a high degree of accuracy.
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Affiliation(s)
- Hao Shang
- School of Chemical and Biomedical Engineering, Forney Hall, Purdue University, West Lafayette, IN 47907-1283, USA
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43
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Grzywa EL, Lee AC, Lee GU, Suter DM. High-resolution analysis of neuronal growth cone morphology by comparative atomic force and optical microscopy. ACTA ACUST UNITED AC 2007; 66:1529-43. [PMID: 17058186 DOI: 10.1002/neu.20318] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [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: 01/21/2023]
Abstract
Neuronal growth cones are motile sensory structures at the tip of axons, transducing guidance information into directional movements towards target cells. The morphology and dynamics of neuronal growth cones have been well characterized with optical techniques; however, very little quantitative information is available on the three-dimensional structure and mechanical properties of distinct subregions. In the present study, we imaged the large Aplysia growth cones after chemical fixation with the atomic force microscope (AFM) and directly compared our data with images acquired by light microscopy methods. Constant force imaging in contact mode in combination with force-distant measurements revealed an average height of 200 nm for the peripheral (P) domain, 800 nm for the transition (T) zone, and 1200 nm for the central (C) domain, respectively. The AFM images show that the filopodial F-actin bundles are stiffer than surrounding F-actin networks. Enlarged filopodia tips are 60 nm higher than the corresponding shafts. Measurements of the mechanical properties of the specific growth cone regions with the AFM revealed that the T zone is stiffer than the P and the C domain. Direct comparison of AFM and optical data acquired by differential interference contrast and fluorescence microscopy revealed a good correlation between these imaging methods. However, the AFM provides height and volume information at higher resolution than fluorescence methods frequently used to estimate the volume of cellular compartments. These findings suggest that AFM measurements on live growth cones will provide a quantitative understanding of how proteins can move between different growth cone regions.
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Affiliation(s)
- Emilie L Grzywa
- School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907-2100, USA
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44
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Abstract
A general approach is described for array-based biochemical sensing that uses contact-free dispersal of compounds into addressable microfabricated reactors. The arrays are composed of 1 to 100 nL volume open reactors that have been microfabricated on quartz substrates using lithography. The open architecture of these reactors allows them to be addressed in parallel or individually with an ink-jet arrayer that is capable of distributing 0.004 to 1 nL volumes of reagents. A seven-step biochemical assay has been conducted on a small array of reactors to demonstrate how they can be integrated with an ink-jet arrayer and optical detector. This nanoreactor assay format appears to overcome several limitations that chip-based microarray technology currently imposes on protein assays: the arrays can be created in a manner that does not expose the biochemical reagents to osmotic stress, independent reactions can be conducted in individual reactors, and the conditions in all of the reactors (e.g., concentration and pH) can be rapidly scanned. We believe that these nanoreactor arrays will be useful for biochemical sensing that involves delicate proteins and protein assemblies.
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Affiliation(s)
- Zhigang Wang
- Schools of Chemical and Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
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Abstract
Supported lipid films are becoming increasingly important tools for the study of membrane protein function because of the availability of high-sensitivity surface analytical and patterning techniques. In this study, we have characterized the physical chemical properties of lipid films assembled on hydrophobic surfaces through the spontaneous adsorption of large unilamellar lipid vesicles composed of dioleoylphosphatidylglycerol (DOPG) and dioleoylphosphatidylcholine (DOPC). The density of the lipid films was measured with surface plasmon resonance spectroscopy as the lipid composition of the vesicles and ionic concentration were varied. As expected, monolayer films were formed, but the density of the monolayers was found to be weakly dependent on the lipid composition of the vesicles and strongly dependent on the ionic concentration of the solution in contact with the monolayer. Atomic force microscopy (AFM) images of the lipid films indicate that they are composed of a homogeneous monolayer. Surface force measurements were used to determine the surface charge and DOPG density of the monolayers. The DOPG content of the films was found to be weakly dependent on the DOPG composition of the vesicles and strongly dependent on the salt concentration of the environment. A model has been developed to describe the behavior of the lipid composition of the films in terms of the hydrophobic, electrostatic, and steric forces acting on the lipid monolayer on the hydrophobic surface.
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Affiliation(s)
- Jin-Won Park
- Schools of Chemical and Biomedical Engineering, Forney Hall of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907-2100, USA
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46
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Shang H, Chang WS, Kan S, Majetich SA, Lee GU. Synthesis and characterization of paramagnetic microparticles through emulsion-templated free radical polymerization. Langmuir 2006; 22:2516-22. [PMID: 16519449 DOI: 10.1021/la052636f] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
A novel method is described for the preparation of high-magnetization paramagnetic microparticles functionalized with a controlled density of poly(ethylene glycol) (PEG) and carboxyl groups. These microparticles were synthesized using four steps: (1) creation of an oil-in-water emulsion in which hydrophobic iron oxide nanoparticles and a UV-activated initiator were distributed in hexane; (2) formation of uniform microparticles through emulsion homogenization and evaporation of hexane; (3) functionalization of the microparticle with a PEG-functionalized surfactant and acrylic acid; and (4) polymerization of the microparticles. Characterization of the microparticles with electron microscopy and light scattering revealed that they were composed of densely packed iron oxide nanoparticles and that the size of the microparticles may be controlled through the pore size of the membrane used to homogenize the emulsion. The concentration of surfactant and acrylic acid used in the third processing step was found to determine the surface chemistry, iron content, and magnetization of the microparticles. Increasing the PEG surfactant to acrylic acid ratio resulted in higher PEG surface densities, lower iron content, and lower magnetization. The resulting microparticles were readily functionalized with antibodies and showed a low propensity for nonspecific protein adsorption. We believe that these microparticles will be useful for magnetic tweezers measurements and bioanalytical devices that require microparticles with a high magnetization.
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Affiliation(s)
- Hao Shang
- School of Chemical Engineering, Forney Hall, Purdue University, West Lafayette, Indiana 47907-1283, USA
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47
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Abstract
An array of micron size reactors has been designed and fabricated on a mesoporous membrane to create a platform for asymmetric biochemical sensing. Fabrication of this device required that a technique be developed to integrate the mesoporous alumina membrane with a polymeric layer that maintains the integrity of the membrane surface and permeability. This device was used to control an enzyme reaction at the surface of the membrane through the diffusion of the substrates from the opposite sides of the membrane. Asymmetric reactions promise new modes of sensing, enhanced stability of delicate biomolecular systems, and enhanced sensitivity and speed in sensing.
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48
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Wang Z, Zeng Q, Luan Y, Wu X, Wan L, Wang C, Lee GU, Yin S, Yang J, Bai C. Voltage-Dependent Scanning Tunneling Microscopy Images of a Copper Complex on Graphite. J Phys Chem B 2003. [DOI: 10.1021/jp034396n] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zhigang Wang
- The Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100080, P. R. China, Lab of Bond Selective Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China, School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, and School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907
| | - Qingdao Zeng
- The Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100080, P. R. China, Lab of Bond Selective Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China, School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, and School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907
| | - Yanbing Luan
- The Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100080, P. R. China, Lab of Bond Selective Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China, School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, and School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907
| | - Xiaojun Wu
- The Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100080, P. R. China, Lab of Bond Selective Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China, School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, and School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907
| | - Lijun Wan
- The Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100080, P. R. China, Lab of Bond Selective Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China, School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, and School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907
| | - Chen Wang
- The Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100080, P. R. China, Lab of Bond Selective Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China, School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, and School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907
| | - Gil U Lee
- The Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100080, P. R. China, Lab of Bond Selective Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China, School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, and School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907
| | - Shuxia Yin
- The Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100080, P. R. China, Lab of Bond Selective Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China, School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, and School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907
| | - Jinlong Yang
- The Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100080, P. R. China, Lab of Bond Selective Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China, School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, and School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907
| | - Chunli Bai
- The Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100080, P. R. China, Lab of Bond Selective Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China, School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, and School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907
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He M, Reid GE, Shang H, Lee GU, McLuckey SA. Dissociation of multiple protein ion charge states following a single gas-phase purification and concentration procedure. Anal Chem 2002; 74:4653-61. [PMID: 12349967 DOI: 10.1021/ac025587+] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [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: 11/28/2022]
Abstract
The formation of a range of precursor ion charge states from a single concentrated and purified charge state, followed by activation of each charge state, is introduced as a means to obtain more protein structural information than is available from dissociation of a single charge state alone. This approach is illustrated using off-resonance collisional activation of the [M + 8H]8+ to [M + 6H]6+ precursor ions of the bacteriophage MS2 viral coat protein following concentration and purification of the [M + 8H]8+ charge state. This range of charge states was selected on the basis of an ion trap collisional activation study of the effects of precursor ion charge state on the dissociation of the [M + 12H]12+ to [M + 5H]5+ ions. Gas-phase ion/ion proton-transfer reactions and the ion parking technique were applied to purify and concentrate selected precursor ion charge states as well as to simplify the product ion spectra. The high-charge-state ions fragment preferentially at the N-terminal side of proline residues while the product ion spectra of the lowest charge states investigated are dominated by C-terminal aspartic acid cleavages. Maximum structural information is obtained by fragmentation of the intermediate-charge states.
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Affiliation(s)
- Min He
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-1393, USA
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Reid GE, Shang H, Hogan JM, Lee GU, McLuckey SA. Gas-phase concentration, purification, and identification of whole proteins from complex mixtures. J Am Chem Soc 2002; 124:7353-62. [PMID: 12071744 DOI: 10.1021/ja025966k] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.8] [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: 11/30/2022]
Abstract
Five proteins present in a relatively complex mixture derived from a whole cell lysate fraction of E. coli have been concentrated, purified, and dissociated in the gas phase, using a quadrupole ion trap mass spectrometer. Concentration of intact protein ions was effected using gas-phase ion/ion proton-transfer reactions in conjunction with mass-to-charge dependent ion "parking" to accumulate protein ions initially dispersed over a range of charge states into a single lower charge state. Sequential ion isolation events interspersed with additional ion parking ion/ion reaction periods were used to "charge-state purify" the protein ion of interest. Five of the most abundant protein components present in the mixture were subjected to this concentration/purification procedure and then dissociated by collisional activation of their intact multiply charged precursor ions. Four of the five proteins were subsequently identified by matching the uninterpreted product ion spectra against a partially annotated protein sequence database, coupled with a novel scoring scheme weighted for the relative abundances of the experimentally observed product ions and the frequency of fragmentations occurring at preferential cleavage sites. The identification of these proteins illustrates the potential of this "top-down" protein identification approach to reduce the reliance on condensed-phase chemistries and extensive separations for complex protein mixture analysis.
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Affiliation(s)
- Gavin E Reid
- Department of Chemistry, 1393 Brown Building, Purdue University, West Lafayette, Indiana 47907-1393, USA
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