1
|
Li J, Bi L, Musolino SF, Wulff JE, Sask KN. Functionalization of Polydimethylsiloxane with Diazirine-Based Linkers for Covalent Protein Immobilization. ACS APPLIED MATERIALS & INTERFACES 2024; 16:1-16. [PMID: 38149968 DOI: 10.1021/acsami.3c08013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
Biomolecule attachment to solid supports is critical for biomedical devices, such as biosensors and implants. Polydimethylsiloxane (PDMS) is commonly used for these applications due to its advantageous properties. To enhance the biomolecule immobilization on PDMS, a novel technique is demonstrated using newly synthesized diazirine molecules for the surface modification of PDMS. This nondestructive process involves a reaction between diazirine molecules and PDMS through C-H insertion with thermal or ultraviolet activation. The success of the PDMS modification is confirmed by various surface characterization techniques. Bovine serum albumin (BSA) and immunoglobulin G (IgG) are strongly attached to the modified PDMS surfaces, and the amount of protein is quantified using iodine-125 radiolabeling. The results demonstrate that PDMS is rapidly functionalized, and the stability of the immobilized proteins is significantly improved with multiple types of diazirine molecules and activation methods. Confocal microscopy provides three-dimensional images of the distribution of immobilized IgG on the surfaces and the penetration of diazirine-based linkers through the PDMS substrate during the coating process. Overall, this study presents a promising new approach for functionalizing PDMS surfaces to enhance biomolecule immobilization, and its potential applications can extend to multimaterial modifications for various diagnostic and medical applications such as microfluidic devices and immunoassays with relevant bioactive proteins.
Collapse
Affiliation(s)
- Jie Li
- School of Biomedical Engineering, McMaster University, Hamilton, Ontario L8S 4L2, Canada
| | - Liting Bi
- Department of Chemistry, University of Victoria, Victoria, British Columbia V8W 3V6, Canada
| | - Stefania F Musolino
- Department of Chemistry, University of Victoria, Victoria, British Columbia V8W 3V6, Canada
| | - Jeremy E Wulff
- Department of Chemistry, University of Victoria, Victoria, British Columbia V8W 3V6, Canada
| | - Kyla N Sask
- School of Biomedical Engineering, McMaster University, Hamilton, Ontario L8S 4L2, Canada
- Department of Materials Science & Engineering, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| |
Collapse
|
2
|
Detecting zeta potential of polydimethylsiloxane (PDMS) in electrolyte solutions with atomic force microscope. J Colloid Interface Sci 2020; 578:116-123. [PMID: 32521351 DOI: 10.1016/j.jcis.2020.05.061] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 05/12/2020] [Accepted: 05/12/2020] [Indexed: 11/22/2022]
Abstract
Zeta potential of PDMS-liquid interface is an important parameter for generating electroosmotic flow in a PDMS microchannel. In this paper, the zeta potentials of a PDMS slab in contacting with electrolyte solutions were evaluated with an atomic force microscope (AFM). As a colloidal probe of the AFM approaches to the surface of a PDMS slab in an electrolyte solution, a force curve is obtained and used to calculate the zeta potential of the PDMS. The effects of the plasma treating time and the aging of the electrolyte solutions on the zeta potential of PDMS surfaces were examined. The experimental results show that the air plasma treating time does not change the zeta potential of PDMS appreciably. Furthermore, the decreased zeta potential of a plasma-treated PDMS in an electrolyte solution is due to liquid aging, not the PDMS itself. Such characteristics probed by AFM provide new understanding of the surface charges of PDMS in electrolyte solutions.
Collapse
|
3
|
Iqbal P, Lu T, Zhang Z, Li Y. Preparation of Multilayer Microcapsules Encapsulating Aqueous Lithium Bromide and Their Mechanical Stability. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.8b02782] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Parvez Iqbal
- School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
| | - Tiejun Lu
- School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
| | - Zhibing Zhang
- School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
| | - Yongliang Li
- School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
| |
Collapse
|
4
|
Bračič M, Mohan T, Kargl R, Griesser T, Hribernik S, Köstler S, Stana-Kleinschek K, Fras-Zemljič L. Preparation of PDMS ultrathin films and patterned surface modification with cellulose. RSC Adv 2014. [DOI: 10.1039/c3ra47380e] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Patterned surface functionalization of PDMS with the biopolymer cellulose via lithographic methods.
Collapse
Affiliation(s)
- Matej Bračič
- Institute for the Engineering and Design of Materials
- University of Maribor
- 2000 Maribor, Slovenia
- Savatech d.o.o. Industrial Rubber Products and Tyres
- 4000 Kranj, Slovenia
| | - Tamilselvan Mohan
- Institute for Chemistry and Technology of Materials
- Graz University of Technology
- 8010 Graz, Austria
| | - Rupert Kargl
- Institute for the Engineering and Design of Materials
- University of Maribor
- 2000 Maribor, Slovenia
| | - Thomas Griesser
- Chair of Chemistry of Polymeric Materials
- University of Leoben
- A-8700 Leoben, Austria
| | - Silvo Hribernik
- Institute for the Engineering and Design of Materials
- University of Maribor
- 2000 Maribor, Slovenia
| | - Stefan Köstler
- Joanneum Research Materials
- Institute for Surface Technologies and Photonics
- 8160 Weiz, Austria
| | - Karin Stana-Kleinschek
- Institute for the Engineering and Design of Materials
- University of Maribor
- 2000 Maribor, Slovenia
| | - Lidija Fras-Zemljič
- Institute for the Engineering and Design of Materials
- University of Maribor
- 2000 Maribor, Slovenia
| |
Collapse
|
5
|
Amorim S, Pires RA, da Costa DS, Reis RL, Pashkuleva I. Interactions between exogenous FGF-2 and sulfonic groups: in situ characterization and impact on the morphology of human adipose-derived stem cells. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:7983-7992. [PMID: 23725085 DOI: 10.1021/la400871c] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
FGF-2 is often used as a supplement to stem cells culture medium aiming at preserving their self-renewal capacity and plasticity through the passages. However, little is known on the influence of the underlying substrate in these interactions. In this study, we have used mixed self-assembled monolayers with different ratios of -SO3H and -OH tail groups to investigate the influence of substrate properties (e.g., charge) on the FGF-2 adsorption and activity. QCM-D data demonstrated that, in the presence of -OH groups, the quantity of the adsorbed FGF-2 is proportional to the percentage of surface -SO3H groups. The bioactivity of the adsorbed FGF-2 follows the same tendency as demonstrated by its interactions with anti-FGF-2. Surprisingly, the adlayer of FGF-2 formed on the surface containing only SO3H-tailed SAMs was similar to the surface with 25% of -SO3H groups, demonstrating that FGF-2 adsorption is not solely driven by electrostatic interactions. We related these results with changes in the morphology of adipose-derived stem cells (ASCs) cultured on the same surfaces.
Collapse
Affiliation(s)
- Sara Amorim
- 3B's Research Group - Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, 4806-909 Taipas, Guimarães, Portugal
| | | | | | | | | |
Collapse
|
6
|
Dhaliwal A, Maldonado M, Lin C, Segura T. Cellular cytoskeleton dynamics modulates non-viral gene delivery through RhoGTPases. PLoS One 2012; 7:e35046. [PMID: 22509380 PMCID: PMC3324413 DOI: 10.1371/journal.pone.0035046] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 03/12/2012] [Indexed: 11/18/2022] Open
Abstract
Although it is well accepted that the constituents of the cellular microenvironment modulate a myriad of cellular processes, including cell morphology, cytoskeletal dynamics and uptake pathways, the underlying mechanism of how these pathways influence non-viral gene transfer have not been studied. Transgene expression is increased on fibronectin (Fn) coated surfaces as a consequence of increased proliferation, cell spreading and active engagement of clathrin endocytosis pathway. RhoGTPases mediate the crosstalk between the cell and Fn, and regulate cellular processes involving filamentous actin, in-response to cellular interaction with Fn. Here the role of RhoGTPases specifically Rho, Rac and Cdc42 in modulation of non-viral gene transfer in mouse mesenchymal stem (mMSCs) plated in a fibronectin microenvironment was studied. More than 90% decrease in transgene expression was observed after inactivation of RhoGTPases using difficile toxin B (TcdB) and C3 transferase. Expression of dominant negative RhoA (RhoAT19N), Rac1(Rac1T17N) and Cdc42 (Cdc42T17N) also significantly reduced polyplex uptake and transgene expression. Interactions of cells with Fn lead to activation of RhoGTPases. However, further activation of RhoA, Rac1 and Cdc42 by expression of constitutively active genes (RhoAQ63L, Rac1Q61L and Cdc42Q61L) did not further enhance transgene expression in mMSCs, when plated on Fn. In contrast, activation of RhoA, Rac1 and Cdc42 by expression of constitutively active genes for cells plated on collagen I, which by itself did not increase RhoGTPase activation, resulted in enhanced transgene expression. Our study shows that RhoGTPases regulate internalization and effective intracellular processing of polyplexes that results in efficient gene transfer.
Collapse
Affiliation(s)
- Anandika Dhaliwal
- Biomedical Engineering Interdepartmental Program, University of California Los Angeles, Los Angeles, California, United States of America
| | - Maricela Maldonado
- Chemical and Biomolecular Engineering Department, University of California Los Angeles, Los Angeles, California, United States of America
| | - Clayton Lin
- Chemical and Biomolecular Engineering Department, University of California Los Angeles, Los Angeles, California, United States of America
| | - Tatiana Segura
- Biomedical Engineering Interdepartmental Program, University of California Los Angeles, Los Angeles, California, United States of America
- Chemical and Biomolecular Engineering Department, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
| |
Collapse
|
7
|
Liu K, Gu P, Hamaker K, Fan ZH. Characterization of bonding between poly(dimethylsiloxane) and cyclic olefin copolymer using corona discharge induced grafting polymerization. J Colloid Interface Sci 2011; 365:289-95. [PMID: 21962541 DOI: 10.1016/j.jcis.2011.09.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 09/02/2011] [Accepted: 09/03/2011] [Indexed: 01/28/2023]
Abstract
Thermoplastics have been increasingly used for fabricating microfluidic devices because of their low cost, mechanical/biocompatible attributes, and well-established manufacturing processes. However, there is sometimes a need to integrate such a device with components made from other materials such as polydimethylsiloxane (PDMS). Bonding thermoplastics with PDMS to produce hybrid devices is not straightforward. We have reported our method to modify the surface property of a cyclic olefin copolymer (COC) substrate by using corona discharge and grafting polymerization of 3-(trimethoxysilyl)propyl methacrylate; the modified surface enabled strong bonding of COC with PDMS. In this paper, we report our studies on the surface modification mechanism using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and contact angle measurement. Using this bonding method, we fabricated a three-layer (COC/PDMS/COC) hybrid device consisting of elastomer-based valve arrays. The microvalve operation was confirmed through the displacement of a dye solution in a fluidic channel when the elastomer membrane was pneumatically actuated. Valve-enabled microfluidic handling was demonstrated.
Collapse
Affiliation(s)
- Ke Liu
- Interdisciplinary Microsystems Group, Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611-6250, USA
| | | | | | | |
Collapse
|
8
|
Gu P, Liu K, Chen H, Nishida T, Fan ZH. Chemical-assisted bonding of thermoplastics/elastomer for fabricating microfluidic valves. Anal Chem 2010; 83:446-52. [PMID: 21121689 DOI: 10.1021/ac101999w] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Thermoplastics such as cyclic olefin copolymer (COC) and polymethylmethacrylate (PMMA) have been increasingly used in fabricating microfluidic devices. However, the state-of-the-art microvalve technology is a polydimethylsiloxane (PDMS)-based three-layer structure. In order to integrate such a valve with a thermoplastics-based microfluidic device, a bonding method for thermoplastics/PDMS must be developed. We report here a method to bond COC with PDMS through surface activation by corona discharge, surface modification using 3-(trimethoxysilyl)propyl methacrylate (TMSPMA), and thermal annealing. The method is also applicable to PMMA. The bonding strength between thermoplastics and PDMS was represented by the peeling force, which was measured using a method established by the International Organization for Standardization (ISO). The bonding strength measurement offered an objective and quantitative indicator for protocol optimization, as well as comparison with other PDMS-associated bonding methods. Using optimized bonding conditions, two valve arrays were fabricated in a COC/PDMS/COC device and cyclic operations of valve closing/opening were successfully demonstrated. The valve-containing devices withstood 100 psi (∼689 KPa) without delamination. Further, we integrated such valve arrays in a device for protein separation and demonstrated isoelectric focusing in the presence of valves.
Collapse
Affiliation(s)
- Pan Gu
- Interdisciplinary Microsystems Group, Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611-6250, United States
| | | | | | | | | |
Collapse
|
9
|
Volcke C, Gandhiraman RP, Gubala V, Doyle C, Fonder G, Thiry PA, Cafolla AA, James B, Williams DE. Plasma functionalization of AFM tips for measurement of chemical interactions. J Colloid Interface Sci 2010; 348:322-8. [DOI: 10.1016/j.jcis.2010.04.042] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Revised: 04/08/2010] [Accepted: 04/19/2010] [Indexed: 11/16/2022]
|
10
|
Kayser MJ, Reinholdt MX, Kaliaguine S. Amine Grafted Silica/SPEEK Nanocomposites as Proton Exchange Membranes. J Phys Chem B 2010; 114:8387-95. [DOI: 10.1021/jp100430h] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marie J. Kayser
- Department of Chemical Engineering, Laval University, Quebec QC G1 V 0A6, Canada
| | - Marc X. Reinholdt
- Department of Chemical Engineering, Laval University, Quebec QC G1 V 0A6, Canada
| | - Serge Kaliaguine
- Department of Chemical Engineering, Laval University, Quebec QC G1 V 0A6, Canada
| |
Collapse
|
11
|
Zhou J, Ellis AV, Voelcker NH. Recent developments in PDMS surface modification for microfluidic devices. Electrophoresis 2010; 31:2-16. [DOI: 10.1002/elps.200900475] [Citation(s) in RCA: 599] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
12
|
Wang Y, Pang X, Zhang Y, Wang H. Characterization of covalent immobilization on the surface of optical fibers by scanning electron microscopy and energy dispersive X-ray spectrometry. SURF INTERFACE ANAL 2009. [DOI: 10.1002/sia.3091] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
13
|
Wang D, Goel V, Oleschuk RD, Horton JH. Surface modification of poly(dimethylsiloxane) with a perfluorinated alkoxysilane for selectivity toward fluorous tagged peptides. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:1080-6. [PMID: 18163653 DOI: 10.1021/la702038t] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Poly(dimethylsiloxane) (PDMS) and similar polymers have proved to be of widespread interest for use in microfluidic and similar microanalytical devices. Surface modification of PDMS is required to extend the range of applications for devices made of this polymer, however. Here we report on the grafting of perfluorooctyltriethoxysilane via hydrolysis onto an oxidized PDMS substrate in order to form a fluorinated microchannel. Such a fluorinated device could be used for separating fluorous tagged proteins or peptides, similar to that which has been recently demonstrated in a capillary electrophoresis system or in an open tubular capillary column. The modified polymer is characterized using chemical force titrations, contact angle measurements, and X-ray photoelectron spectroscopy (XPS). We also report on a novel means of performing electroosmotic measurements on this material to determine the surface zeta potential. As might be expected, contact angle and chemical force titration measurements indicate the fluorinated surface to be highly hydrophobic. XPS indicates that fluorocarbon groups segregate to the surface of the polymer over a period of days following the initial surface modification, presumably driven by a lower surface free energy. One of the most interesting results is the zeta potential measurements, which show that significant surface charge can be maintained across a wide range of pH on this modified polymer, sufficient to promote electroosmotic flow in a microfluidic chip. Matrix-assisted time-of-flight mass spectrometry (MALDI-TOF MS) measurements show that a fluorous-tagged peptide will selectively adsorb on the fluorinated PDMS in aqueous solution, demonstrating that the fluorinated polymer could be used in devices designed for the enrichment or enhanced detection of fluorous-labeled proteins and peptides.
Collapse
Affiliation(s)
- Dan Wang
- Department of Chemistry, Queen's University, Kingston, Ontario, Canada K7L 3N6
| | | | | | | |
Collapse
|
14
|
Wang B, Oleschuk RD, Petkovich PM, Horton JH. Chemical force titrations of antigen- and antibody-modified poly(methylmethacrylate). Colloids Surf B Biointerfaces 2007; 55:107-14. [PMID: 17187966 DOI: 10.1016/j.colsurfb.2006.11.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2006] [Revised: 11/21/2006] [Accepted: 11/21/2006] [Indexed: 11/26/2022]
Abstract
Poly(methylmethacrylate) (PMMA) is a versatile polymer that displays desirable properties for development of cheap and disposable microfluidic devices for sensing biomolecular interactions. Atomic force microscopy (AFM) and chemical force titrations were used to determine the efficacy of surface modifications made to accommodate protein-substrate linkage. AFM images show the effects on surface morphology of carboxylated-, amine-, hCG antigen- and anti-hCG antibody-modified PMMA substrates. Confocal microscopy was used to determine the fluorescent intensity of labeled antibody species on the PMMA substrate, confirming the success of surface antigen/antibody immobilization. Surface pK(1/2) value for carboxylic acid and amine species grafted on PMMA were determined. When carboxylic acid or amine-terminated tips were titrated against PMMA samples terminated with the hCG antigen and anti-hCG antibody, peaks appeared in the force titration curve consistent with the pI range of the antigen or antibody species. Strong adhesive forces were present at pH values above 7.0 when the antigen was present on the PMMA substrate, and these were attributed to hydrophobic interactions between the antigen and the alkane "linker" chain attaching the amine or carboxylate group to the AFM tip. Such hydrophobic interactions were not observed with the carboxylic acid or amine/antibody combinations suggesting that the surface-linked antibody was more resistant to denaturation under higher pH. The results demonstrated the feasibility of using AFM approaches for interrogating protein grafting strategies in the fabrication of PMMA-based microsystems.
Collapse
Affiliation(s)
- Bin Wang
- Cancer Research Institute, Botterell Hall, Queen's University, Kingston, Ontario, Canada
| | | | | | | |
Collapse
|
15
|
Iqbal P, Critchley K, Bowen J, Attwood D, Tunnicliffe D, Evans SD, Preece JA. Fabrication of a nanoparticle gradient substrate by thermochemical manipulation of an ester functionalized SAM. ACTA ACUST UNITED AC 2007. [DOI: 10.1039/b712687e] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
16
|
Mengistu TZ, Goel V, Horton JH, Morin S. Chemical force titrations of functionalized Si(111) surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:5301-7. [PMID: 16732656 DOI: 10.1021/la052776p] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Chemical force titrations-plots of the adhesive force between an atomic force microscope tip and sample as a function of pH-were acquired on alkyl monolayer-derivatized Si(111) surfaces. Gold-coated AFM tips modified with thioalkanoic acid self-assembled monolayers (SAM) were employed. Alkyl monolayer-derivatized Si(111) surfaces terminated with methyl, carboxyl, and amine groups were produced via hydrosilylation reactions between 1-alkene reagents and H-terminated silicon. The functionalized surfaces were characterized using standard surface science techniques (AFM, FTIR, and XPS). Titration of the methyl-terminated surface using the modified (carboxyl-terminated) atomic force microscope tip resulted in a small pH-independent hydrophobic interaction. Titration of the amine-terminated surface using the same tip resulted in the determination of a surface pKa of 5.8 for the amine from the pH value from the maximum in the force titration curve. A pK(1/2) of 4.3 was determined for the carboxyl-terminated Si(111) in a similar way. These results will be discussed in relation to the modified Si(111) surface chemistry and organic layer structure, as well as with respect to existing results on Au surfaces modified with SAMs bearing the same functional groups.
Collapse
Affiliation(s)
- Tadesse Z Mengistu
- Department of Chemistry, York University, 4700 Keele Street, Toronto, Ontario, Canada, M3J 1P3
| | | | | | | |
Collapse
|
17
|
Roman GT, McDaniel K, Culbertson CT. High efficiency micellar electrokinetic chromatography of hydrophobic analytes on poly(dimethylsiloxane) microchips. Analyst 2005; 131:194-201. [PMID: 16440082 DOI: 10.1039/b510765b] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This paper describes a simple method for the effective and rapid separation of hydrophobic molecules on polydimethylsiloxane (PDMS) microfluidic devices using Micellar Electrokinetic Chromatography (MEKC). For these separations the addition of sodium dodecyl sulfate (SDS) served two critical roles - it provided a dynamic coating on the channel wall surfaces and formed a pseudo-stationary chromatographic phase. The SDS coating generated an EOF of 7.1 x 10(-4) cm(2) V(-1) s(-1) (1.6% relative standard deviation (RSD), n = 5), and eliminated the absorption of Rhodamine B into the bulk PDMS. High efficiency separations of Rhodamine B, TAMRA (6-carboxytetramethylrhodamine, succinimidyl ester) labeled amino acids (AA), BODIPY FL CASE (N-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-propionyl)cysteic acid, succinimidyl ester) labeled AA's, and AlexaFluor 488 labeled Escherichia coli bacterial homogenates on PDMS chips were performed using this method. Separations of Rhodamine B and TAMRA labeled AA's using 25 mM SDS, 20% acetonitrile, and 10 mM sodium tetraborate generated efficiencies > 100,000 plates (N) or 3.3 x 10(6) N m(-1) in <25 s with run-to-run migration time reproducibilities <1% RSD over 3 h. Microchips with 30 cm long serpentine separation channels were used to separate 17 BODIPY FL CASE labeled AA's yielding efficiencies of up to 837,000 plates or 3.0 x 10(6) N m(-1). Homogenates of E. coli yielded approximately 30 resolved peaks with separation efficiencies of up to 600,000 plates or 2.4 x 10(6) N m(-1) and run-to-run migration time reproducibilities of <1% RSD over 3 h.
Collapse
Affiliation(s)
- Gregory T Roman
- Department of Chemistry, Kansas State University, KS 66506, USA
| | | | | |
Collapse
|