Open AccessPDMS Compound Adsorption in Context
Author(s) -
Nianzhen Li,
Michael A. Schwartz,
Cristian Ionescu-Zanetti
Publication year - 2009
Publication title -
slas discovery
Language(s) - English
Resource type - Journals
eISSN - 2472-5560
pISSN - 2472-5552
DOI - 10.1177/1087057108327326
Subject(s) - polydimethylsiloxane , adsorption , polystyrene , microfluidics , desorption , materials science , chemical engineering , polymer , drop (telecommunication) , soft lithography , porosity , calcein , nanotechnology , fabrication , analytical chemistry (journal) , chromatography , chemistry , membrane , organic chemistry , composite material , medicine , telecommunications , biochemistry , alternative medicine , pathology , computer science , engineering
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)