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Tsuzuki T, Baassiri K, Mahmoudi Z, Perumal AS, Rajendran K, Rubies GM, Nicolau DV. Hydrophobic Recovery of PDMS Surfaces in Contact with Hydrophilic Entities: Relevance to Biomedical Devices. MATERIALS (BASEL, SWITZERLAND) 2022; 15:2313. [PMID: 35329765 PMCID: PMC8950181 DOI: 10.3390/ma15062313] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/08/2022] [Accepted: 03/16/2022] [Indexed: 11/30/2022]
Abstract
Polydimethylsiloxane (PDMS), a silicone elastomer, is increasingly being used in health and biomedical fields due to its excellent optical and mechanical properties. Its biocompatibility and resistance to biodegradation led to various applications (e.g., lung on a chip replicating blood flow, medical interventions, and diagnostics). The many advantages of PDMS are, however, partially offset by its inherent hydrophobicity, which makes it unsuitable for applications needing wetting, thus requiring the hydrophilization of its surface by exposure to UV or O2 plasma. Yet, the elastomeric state of PDMS translates in a slow, hours to days, process of reducing its surface hydrophilicity-a process denominated as hydrophobic recovery. Using Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM), the present study details the dynamics of hydrophobic recovery of PDMS, on flat bare surfaces and on surfaces embedded with hydrophilic beads. It was found that a thin, stiff, hydrophilic, silica film formed on top of the PDMS material, following its hydrophilization by UV radiation. The hydrophobic recovery of bare PDMS material is the result of an overlap of various nano-mechanical, and diffusional processes, each with its own dynamics rate, which were analyzed in parallel. The hydrophobic recovery presents a hysteresis, with surface hydrophobicity recovering only partially due to a thin, but resilient top silica layer. The monitoring of hydrophobic recovery of PDMS embedded with hydrophilic beads revealed that this is delayed, and then totally stalled in the few-micrometer vicinity of the embedded hydrophilic beads. This region where the hydrophobic recovery stalls can be used as a good approximation of the depth of the resilient, moderately hydrophilic top layer on the PDMS material. The complex processes of hydrophilization and subsequent hydrophobic recovery impact the design, fabrication, and operation of PDMS materials and devices used for diagnostics and medical procedures. Consequently, especially considering the emergence of new surgical procedures using elastomers, the impact of hydrophobic recovery on the surface of PDMS warrants more comprehensive studies.
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Affiliation(s)
- Tomoo Tsuzuki
- Faculty of Engineering and Industrial Science, Industrial Research Institute Swinburne, Swinburne University of Technology, Melbourne, VIC 3122, Australia;
| | - Karine Baassiri
- Department of Bioengineering, Faculty of Engineering, McGill University, Montreal, QC H3A 0E9, Canada; (K.B.); (Z.M.); (A.S.P.); (K.R.); (G.M.R.)
| | - Zahra Mahmoudi
- Department of Bioengineering, Faculty of Engineering, McGill University, Montreal, QC H3A 0E9, Canada; (K.B.); (Z.M.); (A.S.P.); (K.R.); (G.M.R.)
| | - Ayyappasamy Sudalaiyadum Perumal
- Department of Bioengineering, Faculty of Engineering, McGill University, Montreal, QC H3A 0E9, Canada; (K.B.); (Z.M.); (A.S.P.); (K.R.); (G.M.R.)
| | - Kavya Rajendran
- Department of Bioengineering, Faculty of Engineering, McGill University, Montreal, QC H3A 0E9, Canada; (K.B.); (Z.M.); (A.S.P.); (K.R.); (G.M.R.)
| | - Gala Montiel Rubies
- Department of Bioengineering, Faculty of Engineering, McGill University, Montreal, QC H3A 0E9, Canada; (K.B.); (Z.M.); (A.S.P.); (K.R.); (G.M.R.)
| | - Dan V. Nicolau
- Faculty of Engineering and Industrial Science, Industrial Research Institute Swinburne, Swinburne University of Technology, Melbourne, VIC 3122, Australia;
- Department of Bioengineering, Faculty of Engineering, McGill University, Montreal, QC H3A 0E9, Canada; (K.B.); (Z.M.); (A.S.P.); (K.R.); (G.M.R.)
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Filipponi L, Livingston P, Kašpar O, Tokárová V, Nicolau DV. Protein patterning by microcontact printing using pyramidal PDMS stamps. Biomed Microdevices 2016; 18:9. [PMID: 26782964 PMCID: PMC4718951 DOI: 10.1007/s10544-016-0036-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Micro-contact printing, μCP, is a well-established soft-lithography technique for printing biomolecules. μCP uses stamps made of Poly(dimethylsiloxane), PDMS, made by replicating a microstructured silicon master fabricated by semiconductor manufacturing processes. One of the problems of the μCP is the difficult control of the printing process, which, because of the high compressibility of PDMS, is very sensitive to minute changes in the applied pressure. This over-sensitive response leads to frequent and/or uncontrollable collapse of the stamps with high aspect ratios, thus decreasing the printing accuracy and reproducibility. Here we present a straightforward methodology of designing and fabricating PDMS structures with an architecture which uses the collapse of the stamp to reduce, rather than enlarge the variability of the printing. The PDMS stamp, organized as an array of pyramidal micro-posts, whose ceiling collapses when pressed on a flat surface, replicates the structure of the silicon master fabricated by anisotropic wet etching. Upon application of pressure, depending on the size of, and the pitch between, the PDMS pyramids, an air gap is formed surrounding either the entire array, or individual posts. The printing technology, which also exhibits a remarkably low background noise for fluorescence detection, may find applications when the clear demarcation of the shapes of protein patterns and the distance between them are critical, such as microarrays and studies of cell patterning.
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Affiliation(s)
- Luisa Filipponi
- Industrial Research Institute Swinburne, Faculty of Engineering and Industrial Science, Swinburne University of Technology, PO Box 218, VIC, 3122, Australia
| | - Peter Livingston
- Industrial Research Institute Swinburne, Faculty of Engineering and Industrial Science, Swinburne University of Technology, PO Box 218, VIC, 3122, Australia
| | - Ondřej Kašpar
- Faculty of Engineering, Department of Bioengineering, McGill University, Macdonald Engineering Building, Room 378, 817 Sherbrooke Street West, Montreal, QC, H3A 0C3, Canada
| | - Viola Tokárová
- Faculty of Engineering, Department of Bioengineering, McGill University, Macdonald Engineering Building, Room 378, 817 Sherbrooke Street West, Montreal, QC, H3A 0C3, Canada
| | - Dan V Nicolau
- Industrial Research Institute Swinburne, Faculty of Engineering and Industrial Science, Swinburne University of Technology, PO Box 218, VIC, 3122, Australia. .,Faculty of Engineering, Department of Bioengineering, McGill University, Macdonald Engineering Building, Room 378, 817 Sherbrooke Street West, Montreal, QC, H3A 0C3, Canada.
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Hanson KL, Fulga F, Dobroiu S, Solana G, Kaspar O, Tokarova V, Nicolau DV. Polymer surface properties control the function of heavy meromyosin in dynamic nanodevices. Biosens Bioelectron 2016; 93:305-314. [PMID: 27591903 DOI: 10.1016/j.bios.2016.08.061] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 08/16/2016] [Accepted: 08/18/2016] [Indexed: 11/30/2022]
Abstract
The actin-myosin system, responsible for muscle contraction, is also the force-generating element in dynamic nanodevices operating with surface-immobilized motor proteins. These devices require materials that are amenable to micro- and nano-fabrication, but also preserve the bioactivity of molecular motors. The complexity of the protein-surface systems is greatly amplified by those of the polymer-fluid interface; and of the structure and function of molecular motors, making the study of these interactions critical to the success of molecular motor-based nanodevices. We measured the density of the adsorbed motor protein (heavy meromyosin, HMM) using quartz crystal microbalance; and motor bioactivity with ATPase assay, on a set of model surfaces, i.e., nitrocellulose, polystyrene, poly(methyl methacrylate), and poly(butyl methacrylate), poly(tert-butyl methacrylate). A higher hydrophobicity of the adsorbing material translates in a higher total number of HMM molecules per unit area, but also in a lower uptake of water, and a lower ratio of active per total HMM molecules per unit area. We also measured the motility characteristics of actin filaments on the model surfaces, i.e., velocity, smoothness and deflection of movement, determined via in vitro motility assays. The filament velocities were found to be controlled by the relative number of active HMM per total motors, rather than their absolute surface density. The study allowed the formulation of the general engineering principles for the selection of polymeric materials for the manufacturing of dynamic nanodevices using protein molecular motors.
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Affiliation(s)
- Kristi L Hanson
- Industrial Research Institute Swinburne, Swinburne University of Technology, Hawthorn, Victoria, 3122 Australia
| | - Florin Fulga
- Department of Electrical Engineering and Electronics, The University of Liverpool, Liverpool, L693GJ United Kingdom
| | - Serban Dobroiu
- Department of Electrical Engineering and Electronics, The University of Liverpool, Liverpool, L693GJ United Kingdom
| | - Gerardin Solana
- Industrial Research Institute Swinburne, Swinburne University of Technology, Hawthorn, Victoria, 3122 Australia
| | - Ondrej Kaspar
- Department of Bioengineering, McGill University, Montreal, Quebec, H3A0C3 Canada
| | - Viola Tokarova
- Department of Bioengineering, McGill University, Montreal, Quebec, H3A0C3 Canada
| | - Dan V Nicolau
- Industrial Research Institute Swinburne, Swinburne University of Technology, Hawthorn, Victoria, 3122 Australia; Department of Electrical Engineering and Electronics, The University of Liverpool, Liverpool, L693GJ United Kingdom; Department of Bioengineering, McGill University, Montreal, Quebec, H3A0C3 Canada.
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Spampinato S, Cacciato G, Zimbone M, Ruffino F, Grimaldi M. Quantitative evaluation of surface topographical changes of Au thin films after DNA immobilization. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2015.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Nicolau DV, Ivanova EP, Fulga F, Filipponi L, Viezzoli A, Dobroiu S, Alekseeva YV, Pham DK. Protein immobilisation on micro/nanostructures fabricated by laser microablation. Biosens Bioelectron 2010; 26:1337-45. [PMID: 20705444 DOI: 10.1016/j.bios.2010.07.044] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Revised: 06/29/2010] [Accepted: 07/13/2010] [Indexed: 11/16/2022]
Abstract
The performance of biomedical microdevices requires the accurate control of the biomolecule concentration on the surface, as well as the preservation of their bioactivity. This desideratum is even more critical for proteins, which present a significant propensity for surface-induced denaturation, and for microarrays, which require high multiplexing. We have previously proposed a method for protein immobilisation on micro/nanostructures fabricated via laser ablation of a thin metal layer deposited on a transparent polymer. This study investigates the relationship between the properties of the micro/nanostructured surface, i.e., topography and physico-chemistry, and protein immobilisation, for five, molecularly different proteins, i.e., lysozyme, myoglobin, α-chymotrypsin, human serum albumin, and human immunoglobulin. Protein immobilisation on microstructures has been characterised using quantitative fluorescence measurements and atomic force microscopy. It has been found that the sub-micrometer-level, combinatorial nature of the microstructure translates in a 3-10-fold amplification of protein adsorption, as compared to flat, chemically homogenous polymeric surfaces. This amplification is more pronounced for smaller proteins, as they can capitalize better on the newly created surface and variability of the nano-environments.
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Affiliation(s)
- Dan V Nicolau
- Department of Electrical Engineering and Electronics, The University of Liverpool, Brownlow Hill, L69 3GJ, UK.
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Sawant PD, Sabri YM, Ippolito SJ, Bansal V, Bhargava SK. In-depth nano-scale analysis of complex interactions of Hg with gold nanostructures using AFM-based power spectrum density method. Phys Chem Chem Phys 2009; 11:2374-8. [DOI: 10.1039/b816592k] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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