Sage Journals: Discover world-class research

Abstract

Soft lithography of polydimethylsiloxane (PDMS), an elastomeric polymer, has enabled rapid and inexpensive fabrication of microfluidic devices for various biotechnology applications. However, concerns remain about adsorption of compounds on PDMS surfaces because of its porosity and hydrophobicity. Here, the adsorption of 2 small fluorescent dyes of different hydrophobicity (calcein and 5- (and 6-)carboxytetramethylrhodamine (TMR)) on PDMS surface has been systematically characterized, and PDMS adsorption has been compared with 2 traditional substrates: glass and polystyrene. To characterize adsorption in a regimen that is more relevant to microfluidic applications, the adsorption and desorption of the 2 compounds in PDMS microfluidic channels under flow conditions were also studied. Results showed that there was minimal adsorption of the hydrophilic compound calcein on PDMS, whereas the more hydrophobic TMR adsorbed on PDMS up to 4 times of that on glass or polystyrene. Under flow conditions, the desorption profiles and times needed to drop desorbed compound concentrations to negligible levels (desorption time constant, 10-42 s) were characterized. In the worst case scenario, after a 4-min exposure to TMR, 4 min of continuous wash resulted in compound concentrations in the microchannels to drop to values below 2 × 10^{— 5} of the initial concentration. (Journal of Biomolecular Screening 2009:194-202)

Keywords

microfluidic flow compound adsorption desorption hydrophobic fluorescence

References

Lipinski CA , Lombardo F. , Dominy BW , Feeney PJ : Experimental and computational approaches to estimate solubility and permeability in drug discovery and development settings. Adv Drug Deliv Rev 2001;46:3-26.

Xia YN , Whitesides GM : Soft lithography. Angew Chem Int Ed 1998;37:551-575.

Quake SR , Scherer A. : From micro- to nanofabrication with soft materials. Science 2000;290:1536-1540.

Evans J. : Microfluidics: wet and potentially wild. Chemistry World 2006;3:44-48.

Lee JN , Park C. , Whitesides GM : Solvent compatibility of poly(dimethylsiloxane)-based microfluidic devices . Anal Chem 2003;75:6544-6554.

Theodoridis G. , Lontou MA , Michopoulos F. , Sucha M. , Gondova T. : Study of multiple solid-phase microextraction combined off-line with high performance liquid chromatography-application in the analysis of pharmaceuticals in urine. Anal Chim Acta 2004;516:197-204.

Toepke MW , Beebe DJ : PDMS absorption of small molecules and consequences in microfluidic applications . Lab on a Chip 2006;6:1484-1486.

Monahan J. , Gewirth AA , Nuzzo RG : Indirect fluorescence detection of simple sugars via high-pH electrophoresis in poly(dimethylsiloxane) microfluidic chips. Electrophoresis 2002;23:2347-2354.

ChemAxon Kft., Budapest, Hungary; Demo software online at: http:// www.Chemaxon.Com/demosite/marvin/index.html

10.

Bhal SK , Kassam K. , Peirson IG , Pearl GM : The rule of five revisited: applying Log D in place of Log P in drug-likeness filters. Mol Pharm 2007;4:556-560.

11.

ChemIDplus advanced. Retrieved from http://chem.sis.nlm.nih.gov/chemidplus/chemidheavy.jsp

12.

Fowler SD , Greenspan P. : Application of Nile red, a fluorescent hydrophobic probe, for the detection of neutral lipid deposits in tissue sections: comparison with oil red o. J Histochem Cytochem 1985;33:833-836.

13.

Kasurinen J. : A novel fluorescent fatty acid, 5-methyl-bdy-3-dodecanoic acid, is a potential probe in lipid transport studies by incorporating selectively to lipid classes of BHK cells. Biochem Biophys Res Commun 1992 ; 187:1594-1601.

14.

Makrigiorgos GM : Detection of lipid peroxidation on erythrocytes using the excimer-forming property of a lipophilic BODIPY fluorescent dye . J Biochem Biophys Methods 1997;35:23-35.

15.

Spring KR , Davidson MW : Basic concepts and formulas in microscopy: http://www.Microscopyu.Com/tutorials/java/depthoffield/index.html

16.

Chizmadzhev YA , Zarnitsin VG , Weaver JC , Potts RO : Mechanism of electroinduced ionic species transport through a multilamellar lipid system. Biophys J 1995;68:749-765.

17.

Tanford C. : Physical Chemistry of Macromolecules. New York: Wiley, 1961.

18.

Freitas RA Jr. : Nanomedicine: http://www.Foresight.Org/nanomedicine/ch03_0.html

19.

Nakanishi K. , Sakiyama T. , Imamura K. : On the adsorption of proteins on solid surfaces, a common but very complicated phenomenon. J Biosci Bioeng 2001;91:233-244.

20.

Hawkins KR , Steedman MR , Baldwin RR , Fu E. , Ghosal S. , Yager P. : A method for characterizing adsorption of flowing solutes to microfluidic device surfaces. Lab on a Chip 2007;7:281-285.

21.

Harada Y. , Girolami GS , Nuzzo RG : Growth kinetics and morphology of self-assembled monolayers formed by contact printing 7-octenyltrichlorosilane and octadecyltrichlorosilane on Si(100) wafers. Langmuir 2004;20:10878-10888.

22.

Shurmer B. , Pawliszyn J. : Determination of distribution constants between a liquid polymeric coating and water by a solid-phase microextraction technique with a flow-through standard water system. Anal Chem 2000;72:3660-3664.

23.

Hu S. , Ren X. , Bachman M. , Sims CE , Li GP , Allbritton N. : Surface modification of poly(dimethylsiloxane) microfluidic devices by ultraviolet polymer grafting. Anal Chem 2002;74:4117-4123.

24.

Hu S. , Ren X. , Bachman M. , Sims CE , Li GP , Allbritton NL : Surface-directed, graft polymerization within microfluidic channels. Anal Chem 2004;76:1865-1870.

25.

Hu S. , Ren X. , Bachman M. , Sims CE , Li GP , Allbritton NL : Tailoring the surface properties of poly(dimethylsiloxane) microfluidic devices . Langmuir 2004;20:5569-5574.

26.

Jon S. , Seong J. , Khademhosseini A. , Tran T-NT , Laibinis PE , Langer R. : Construction of nonbiofouling surfaces by polymeric self-assembled monolayers . Langmuir 2003;19:9989-9993.

27.

Ostuni E. , Chen CS , Ingber DE , Whitesides GM : Selective deposition of proteins and cells in arrays of microwells. Langmuir 2001;17:2828-2834.

28.

Eddington DT , Puccinelli JP , Beebe DJ : Thermal aging and reduced hydrophobic recovery of polydimethylsiloxane. Sensors and Actuators B-Chemical 2006;114:170-172.

29.

Chang W-J. , Akin D. , Sedlak M. , Ladisch MR , Bashir R. : Poly(dimethylsiloxane) (PDMS) and silicon hybrid biochip for bacterial culture . Biomed Microdevices 2003;5:281-290.

PDMS Compound Adsorption in Context

Abstract

Keywords

References