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Ando T, Fukuda S, Ngo KX, Flechsig H. High-Speed Atomic Force Microscopy for Filming Protein Molecules in Dynamic Action. Annu Rev Biophys 2024; 53:19-39. [PMID: 38060998 DOI: 10.1146/annurev-biophys-030722-113353] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2024]
Abstract
Structural biology is currently undergoing a transformation into dynamic structural biology, which reveals the dynamic structure of proteins during their functional activity to better elucidate how they function. Among the various approaches in dynamic structural biology, high-speed atomic force microscopy (HS-AFM) is unique in the ability to film individual molecules in dynamic action, although only topographical information is acquirable. This review provides a guide to the use of HS-AFM for biomolecular imaging and showcases several examples, as well as providing information on up-to-date progress in HS-AFM technology. Finally, we discuss the future prospects of HS-AFM in the context of dynamic structural biology in the upcoming era.
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Affiliation(s)
- Toshio Ando
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa, Japan;
| | - Shingo Fukuda
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa, Japan;
| | - Kien X Ngo
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa, Japan;
| | - Holger Flechsig
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa, Japan;
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2
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Kolandaivelu K, Bailey L, Buzzi S, Zucker A, Milleret V, Ziogas A, Ehrbar M, Khattab AA, Stanley JRL, Wong GK, Zani B, Markham PM, Tzafriri AR, Bhatt DL, Edelman ER. Ultra-hydrophilic stent platforms promote early vascular healing and minimise late tissue response: a potential alternative to second-generation drug-eluting stents. EUROINTERVENTION 2017; 12:2148-2156. [PMID: 27993749 DOI: 10.4244/eij-d-15-00497] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
AIMS Simple surface modifications can enhance coronary stent performance. Ultra-hydrophilic surface (UHS) treatment of contemporary bare metal stents (BMS) was assessed in vivo to verify whether such stents can provide long-term efficacy comparable to second-generation drug-eluting stents (DES) while promoting healing comparably to BMS. METHODS AND RESULTS UHS-treated BMS, untreated BMS and corresponding DES were tested for three commercial platforms. A thirty-day and a 90-day porcine coronary model were used to characterise late tissue response. Three-day porcine coronary and seven-day rabbit iliac models were used for early healing assessment. In porcine coronary arteries, hydrophilic treatment reduced intimal hyperplasia relative to the BMS and corresponding DES platforms (1.5-fold to threefold reduction in 30-day angiographic and histological stenosis; p<0.04). Endothelialisation was similar on UHS-treated BMS and untreated BMS, both in swine and rabbit models, and lower on DES. Elevation in thrombotic indices was infrequent (never observed with UHS, rare with BMS, most often with DES), but, when present, correlated with reduced endothelialisation (p<0.01). CONCLUSIONS Ultra-hydrophilic surface treatment of contemporary stents conferred good healing while moderating neointimal and thrombotic responses. Such surfaces may offer safe alternatives to DES, particularly when rapid healing and short dual antiplatelet therapy (DAPT) are crucial.
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Affiliation(s)
- Kumaran Kolandaivelu
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
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3
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Kuo ZK, Fang MY, Wu TY, Yang T, Tseng HW, Chen CC, Cheng CM. Hydrophilic films: How hydrophilicity affects blood compatibility and cellular compatibility. ADVANCES IN POLYMER TECHNOLOGY 2017. [DOI: 10.1002/adv.21820] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Zong-Keng Kuo
- Institute of Nanoengineering and Microsystems; National Tsing Hua University; Hsinchu City Taiwan
| | - Mei-Yen Fang
- New Research Department; Eternal Materials Co. Ltd.; Kaohsiung City Taiwan
| | - Tu-Yi Wu
- New Research Department; Eternal Materials Co. Ltd.; Kaohsiung City Taiwan
| | - Ted Yang
- New Research Department; Eternal Materials Co. Ltd.; Kaohsiung City Taiwan
| | - Hsiang-Wen Tseng
- Department and Institute of Pharmacology; National Yang Ming University; Taipei City Taiwan
| | - Chih-Chen Chen
- Institute of Nanoengineering and Microsystems; National Tsing Hua University; Hsinchu City Taiwan
| | - Chao-Min Cheng
- Institute of Biomedical Engineering; National Tsing Hua University; Hsinchu City Taiwan
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4
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Raczkowska J, Prauzner-Bechcicki S, Dąbczyński P, Szydlak R. Elasticity patterns induced by phase-separation in polymer blend films. THIN SOLID FILMS 2017; 624:181-186. [PMID: 29681664 PMCID: PMC5909711 DOI: 10.1016/j.tsf.2017.01.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Systematical studies on the impact of the thickness of thin films composed of polystyrene (PS) or poly(ethylene oxide) (PEO) on the effective elasticity of polymer-decorated soft polydimethylsiloxane substrate were performed. For both investigated polymer films, elasticity parameter was determined from force-displacement curves recorded using atomic force microscopy. Effective stiffness of supported film grows monotonically with film thickness, starting from the value comparable to the elasticity of soft support and reaching plateau for polymer layers thicker than 200 nm. In contrary, for films cast on hard support no significant thickness dependence of elasticity was observed and the value of elasticity parameter was similar to the one of the substrate. Based on these results, non-conventional method to produce elasticity patterns of various shapes and dimensions induced by phase-separation process in symmetric and asymmetric PS:PEO blend films on soft support was demonstrated. Elevated PS domains were characterized by elasticity parameter 2 times higher than lower PEO matrix. In contrary, adhesion force was increased more than 3 times for PEO regions, as compared to PS areas.
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Affiliation(s)
- Joanna Raczkowska
- The Marian Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30-428 Kraków, Poland
| | - Szymon Prauzner-Bechcicki
- The Henryk Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31-342 Kraków, Poland
| | - Paweł Dąbczyński
- The Marian Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30-428 Kraków, Poland
| | - Renata Szydlak
- Chair of Medical Biochemistry, Jagiellonian University Medical College, Kopernika 7, 31-034 Kraków, Poland
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5
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Thampi S, Nandkumar AM, Muthuvijayan V, Parameswaran R. Differential Adhesive and Bioactive Properties of the Polymeric Surface Coated with Graphene Oxide Thin Film. ACS APPLIED MATERIALS & INTERFACES 2017; 9:4498-4508. [PMID: 28090771 DOI: 10.1021/acsami.6b14863] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Surface engineering of implantable devices involving polymeric biomaterials has become an essential aspect for medical implants. A surface enhancement technique can provide an array of unique surface properties that improve its biocompatibility and functionality as an implant. Polyurethane-based implants that have found extensively acclaimed usage as an implant in biomedical applications, especially in the area of cardiovascular devices, still lack any mechanism to ward off bacterial or platelet adhesion. To bring out such a defense mechanism we are proposing a surface modification technique. Graphene oxide (GO) in very thin film form was wrapped onto the electrospun fibroporous polycarbonate urethane (PCU) membrane (GOPCU) by a simple method of electrospraying. In the present study, we have developed a simple single-step method for coating a polymeric substrate with a thin GO film and evaluated the novel antiadhesive activity of these films. SEM micrographs after coating showed the presence of very thin GO films over the PCU membrane. On the GOPCU surface, the contact angle was shifted by ∼30°, making the hydrophobic PCU surface slightly hydrophilic, while Raman spectral characterization and mapping showed the presence and distribution of GO over 75% of the membrane. A reduced platelet adhesion on the GOPCU surface was observed; meanwhile, bacterial adhesion also got reduced by 85% for Staphylococcus aureus (Gram positive, cocci) and 64% for Pseudomonas aeruginosa (Gram negative, bacilli). A cell adhesion study conducted using mammalian fibroblast cells projected its proliferation percentage in a MTT assay, with 82% cell survival on PCU and 86% on GOPCU after 24 h culture, while a study for an extended period of 72 h showed 87% of survival on PCU and 88% on GOPCU. This plethora of functionalities by a simple modification technique makes thin GO films a self-sufficient surface engineering material for future biomedical applications.
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Affiliation(s)
- Sudhin Thampi
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras , Chennai 600036, India
| | | | - Vignesh Muthuvijayan
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras , Chennai 600036, India
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6
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Abstract
The coronary stent has propelled our understanding of the term "biocompatibility." Stents are expanded at sites of arterial blockage and mechanically reestablish blood flow. This simplicity belies the complex reactions that occur when a stent contacts living substrates. Biocompatible seek to elicit the intended response; stents should perform rather than merely exist. Because performance is assessed in the patient, stent biocompatibility is the multiscale examination of material and cell, and of material, structure, and device in the context of cell, tissue, and organism. This review tracks major biomaterial advances in coronary stent design and discusses biocompatibility clinical performance.
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Affiliation(s)
- Kumaran Kolandaivelu
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA.
| | - Farhad Rikhtegar
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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7
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Prauzner-Bechcicki S, Raczkowska J, Madej E, Pabijan J, Lukes J, Sepitka J, Rysz J, Awsiuk K, Bernasik A, Budkowski A, Lekka M. PDMS substrate stiffness affects the morphology and growth profiles of cancerous prostate and melanoma cells. J Mech Behav Biomed Mater 2014; 41:13-22. [PMID: 25460399 DOI: 10.1016/j.jmbbm.2014.09.020] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 09/19/2014] [Accepted: 09/22/2014] [Indexed: 11/28/2022]
Abstract
A deep understanding of the interaction between cancerous cells and surfaces is particularly important for the design of lab-on-chip devices involving the use of polydimethylsiloxane (PDMS). In our studies, the effect of PDMS substrate stiffness on mechanical properties of cancerous cells was investigated in conditions where the PDMS substrate is not covered with any of extracellular matrix proteins. Two human prostate cancer (Du145 and PC-3) and two melanoma (WM115 and WM266-4) cell lines were cultured on two groups of PDMS substrates that were characterized by distinct stiffness, i.e. 0.75 ± 0.06 MPa and 2.92 ± 0.12 MPa. The results showed the strong effect on cellular behavior and morphology. The detailed analysis of chemical and physical properties of substrates revealed that cellular behavior occurs only due to substrate elasticity.
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Affiliation(s)
- Szymon Prauzner-Bechcicki
- The Henryk Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31-342 Kraków, Poland
| | - Joanna Raczkowska
- The Marian Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Kraków, Poland
| | - Ewelina Madej
- The Marian Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Kraków, Poland
| | - Joanna Pabijan
- The Henryk Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31-342 Kraków, Poland
| | - Jaroslav Lukes
- Czech Technical University in Prague, Faculty of Mechanical Engineering, Technicka 4, 16607 Prague, Czech Republic
| | - Josef Sepitka
- Czech Technical University in Prague, Faculty of Mechanical Engineering, Technicka 4, 16607 Prague, Czech Republic
| | - Jakub Rysz
- The Marian Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Kraków, Poland
| | - Kamil Awsiuk
- The Marian Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Kraków, Poland
| | - Andrzej Bernasik
- Faculty of Physics and Applied Computer Science & Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, Reymonta 19, 30-049 Kraków, Poland
| | - Andrzej Budkowski
- The Marian Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Kraków, Poland
| | - Małgorzata Lekka
- The Henryk Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31-342 Kraków, Poland.
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Ando T, Uchihashi T, Scheuring S. Filming biomolecular processes by high-speed atomic force microscopy. Chem Rev 2014; 114:3120-88. [PMID: 24476364 PMCID: PMC4076042 DOI: 10.1021/cr4003837] [Citation(s) in RCA: 239] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Indexed: 12/21/2022]
Affiliation(s)
- Toshio Ando
- Department of Physics, and Bio-AFM Frontier
Research Center, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
- CREST,
Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi 332-0012, Japan
| | - Takayuki Uchihashi
- Department of Physics, and Bio-AFM Frontier
Research Center, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
- CREST,
Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi 332-0012, Japan
| | - Simon Scheuring
- U1006
INSERM/Aix-Marseille Université, Parc Scientifique et Technologique
de Luminy Bâtiment Inserm TPR2 bloc 5, 163 avenue de Luminy, 13288 Marseille Cedex 9, France
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Abstract
Glaucoma drainage devices (GDDs) create an alternate aqueous pathway by channeling aqueous from the anterior chamber through a long tube to an equatorial plate, inserted under the conjunctiva, which promotes bleb formation. GDDs are being used more frequently in the treatment of glaucoma, both as the primary procedure of choice and following failure of trabeculectomy operations. This article outlines the current concepts involving different GDDs, surgical techniques and a review of the current literature. In addition, the importance of the biomaterial and its implications for the success of the operation are discussed.
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Affiliation(s)
- Ramesh S Ayyala
- Tulane University Medical Center, Glaucoma Service, Dept. of Ophthalmology, Tulane University, New Orleans, LA 70112, USA.
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10
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Choong C, Foord JS, Griffiths JP, Parker EM, Baiwen L, Bora M, Moloney MG. Post-polymerisation modification of surface chemical functionality and its effect on protein binding. NEW J CHEM 2012. [DOI: 10.1039/c2nj00002d] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
Atomic force microscope (AFM) is unique in its capability to capture high-resolution images of biological samples in liquids. This capability will become more versatile to biological sciences if AFM additionally acquires an ability of high-speed imaging, because "direct and real-time visualization" is a straightforward and powerful means to understand biomolecular processes. However, the imaging speed of conventional AFM is too slow to capture moving protein molecules at high resolution. In order to fill this large gap, various efforts have been carried out in the past decade. In this chapter, the past efforts for increasing the scan rate and reduction of tip-sample interaction force of AFM and demonstration of direct visualization of biomolecular processes are described.
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12
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Yamamoto D, Uchihashi T, Kodera N, Yamashita H, Nishikori S, Ogura T, Shibata M, Ando T. High-Speed Atomic Force Microscopy Techniques for Observing Dynamic Biomolecular Processes. Methods Enzymol 2010; 475:541-64. [DOI: 10.1016/s0076-6879(10)75020-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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13
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Akkouch A, Shi G, Zhang Z, Rouabhia M. Bioactivating electrically conducting polypyrrole with fibronectin and bovine serum albumin. J Biomed Mater Res A 2010; 92:221-31. [DOI: 10.1002/jbm.a.32357] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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14
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Saravia V, Toca-Herrera JL. Substrate influence on cell shape and cell mechanics: HepG2 cells spread on positively charged surfaces. Microsc Res Tech 2009; 72:957-64. [DOI: 10.1002/jemt.20742] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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15
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Sengonul M, Sousa A, Libera M. Selective adsorption of surface-modified ferritin on a phase-separated polymer blend. Colloids Surf B Biointerfaces 2009; 73:152-5. [DOI: 10.1016/j.colsurfb.2009.05.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2008] [Revised: 04/30/2009] [Accepted: 05/06/2009] [Indexed: 10/20/2022]
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16
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Alves P, Kaiser JP, Haack J, Salk N, Bruinink A, de Sousa HC, Gil MH. Surface modification of thermoplastic polyurethane in order to enhance reactivity and avoid cell adhesion. Colloid Polym Sci 2009. [DOI: 10.1007/s00396-009-2116-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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18
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Wu G, Paz MD, Chiussi S, Serra J, González P, Wang YJ, Leon B. Excimer laser chemical ammonia patterning on PET film. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2009; 20:597-606. [PMID: 18853239 DOI: 10.1007/s10856-008-3600-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2007] [Accepted: 09/23/2008] [Indexed: 05/26/2023]
Abstract
Laser is a promising technique used for biopolymer surface modification with micro and/or nano features. In this work, a 193 nm excimer laser was used for poly (ethylene terephthalate) (PET) surfaces chemical patterning. The ablation threshold of the PET film used in the experiments was 62 mJ/cm(2) measured before surface modification. Surface chemical patterning was performed by irradiating PET film in a vacuum chamber filled with ammonia at the flux of 10, 15, 20, 25 ml/min. Roughness of the surface characterized by profilometry showed that there were no significant observed change after modification comparing original film. But the hydrophilicity of the surface increased after patterning and a minimum water contact angle was obtained at the gas flux of 20 ml/min. FT-IR/ATR results showed the distinct amino absorption bands presented at 3352 cm(-1)and 1613 cm(-1) after modification and XPS binding energies of C(1s) at 285.5 eV and N(1s) at 399.0 eV verified the existence of C-N bond formation on the PET film surface. Tof-SIMS ions mapping used to identify the amine containing fragments corroborates that amino grafting mainly happened inside the laser irradiation area of the PET surface. A hypothesized radical reaction mechanism proposes that the collision between radicals in ammonia and on the PET surface caused by the incident laser provokes the grafting of amino groups.
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Affiliation(s)
- G Wu
- Department of Applied Physics, University of Vigo, Rua Maxwell, Vigo, Spain.
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19
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Kumar AMS, Sivakova S, Fox JD, Green JE, Marchant RE, Rowan SJ. Molecular engineering of supramolecular scaffold coatings that can reduce static platelet adhesion. J Am Chem Soc 2008; 130:1466-76. [PMID: 18177047 DOI: 10.1021/ja0775927] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Novel supramolecular coatings that make use of low-molecular weight ditopic monomers with guanine end groups are studied using fluid tapping AFM. These molecules assemble on highly oriented pyrolytic graphite (HOPG) from aqueous solutions to form nanosized banding structures whose sizes can be systematically tuned at the nanoscale by tailoring the molecular structure of the monomers. The nature of the self-assembly in these systems has been studied through a combination of the self-assembly of structural derivatives and molecular modeling. Furthermore, we introduce the concept of using these molecular assemblies as scaffolds to organize functional groups on the surface. As a first demonstration of this concept, scaffold monomers that contain a monomethyl triethyleneglycol branch were used to organize these "functional" units on a HOPG surface. These supramolecular grafted assemblies have been shown to be stable at biologically relevant temperatures and even have the ability to significantly reduce static platelet adhesion.
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Affiliation(s)
- Aryavarta M S Kumar
- Center for Cardiovascular Biomaterials, Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106, USA
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20
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Ando T, Uchihashi T, Kodera N, Yamamoto D, Miyagi A, Taniguchi M, Yamashita H. High-speed AFM and nano-visualization of biomolecular processes. Pflugers Arch 2007; 456:211-25. [DOI: 10.1007/s00424-007-0406-0] [Citation(s) in RCA: 201] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2007] [Accepted: 11/15/2007] [Indexed: 11/28/2022]
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21
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Chun JA, Lee WH, Han MO, Lee JW, Yi YB, Park GY, Chung CH. Optimization of abiotic factors for improved growth and extracellular production of recombinant fungal phytase in sesame hairy root cultures. BIOTECHNOL BIOPROC E 2007. [DOI: 10.1007/bf02931099] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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22
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Abstract
Chemical and biosensors operate as direct sample contact systems; as such, the response of the biomatrix to their presence is as important as their response to the targeted analyte. There needs to be greater research emphasis on the response of biofluids to sensors because of the impact on sensor performance. Mainly, this is the result of deposited biolayers through the adsorption of colloids and proteins, followed by a more complex surface-active system: whole cells. Sensor surface engineering and controlled sample presentation through fluidics are likely to be able to mitigate some of these effects. Overall there needs to be a convergence with rapidly evolving research strategies in biomaterials if sensors are to make the full transition from the laboratory to the real world.
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Affiliation(s)
- P Vadgama
- IRC in Biomedical Materials, Queen Mary University of London, Mile End Road, London, UK
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23
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Ateh DD, Waterworth A, Walker D, Brown BH, Navsaria H, Vadgama P. Impedimetric sensing of cells on polypyrrole-based conducting polymers. J Biomed Mater Res A 2007; 83:391-400. [PMID: 17450583 DOI: 10.1002/jbm.a.31308] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Polypyrrole (PPy) is a conducting polymer that may be electrochemically generated with the incorporation of any anionic species, including net-negatively charged biological molecules such as proteins and polysaccharides. In this article, dermatan and chloride-loaded PPy films were prepared on gold sputter-coated coverslips and various skin derived cells were studied on them by electrochemical impedance spectroscopy. Impedance spectra in the frequency range 1-100 kHz were either determined at specific times or impedance was monitored continuously at specific frequencies. An equivalent impedance circuit was fitted to the recorded impedance spectra to obtain parameters whose contributions could be mapped to intracellular and intercellular current pathways, and the membrane properties of cells. Results show cell-induced impedance changes were detected over PPy modified electrodes and were dependent on cell density and type, monitoring frequency, material composition, and treatment. Lower cell densities were detected on PPy when compared with bare gold. Keratinocyte confluence, as determined by impedimetric analysis, was reached more rapidly on PPy than on gold. This was consistent with previous, more cumbersome, biochemical assays. Electrical equivalent circuit analysis provided evidence that the technique may be extended to discriminate cell type because of the intracellular and intercellular resistance, and cell membrane capacitance being related to cell morphology.
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Affiliation(s)
- D D Ateh
- IRC in Biomedical Materials, Queen Mary University of London, London, United Kingdom.
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24
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Abstract
Biocompatibility is key to the performance of any material in a biological environment. This review outlines current opinion on the factors that lead to biocompatibility and focuses on the interactions that occur at the interface between material and environment. The sequence of events, from protein adsorption, cell attachment and behavior, to biocompatibility, is traced. Although these processes are studied and reported widely, there is, as yet, little published evidence that implant biocompatibility can be enhanced in the long term by surface engineering. This lack of evidence does not necessarily imply a lack of effect, but may be ascribed to a lack of robust characterization and poor modeling of the implant environment.
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