Authors: C.J. Chun, K. Lenghaus, L. Riedel, A. Bhalkikar and J.J. Hickman
Affilation: University of Central Florida, United States
Pages: 674 - 677
Keywords: protein adsorption, PEG, microfluidics systems, flow effect
Microfabrication technology has been used to create new microfluidics systems for bioanalytical and medical device applications in the last decade. The handling of relatively small amounts of analytes, at significantly lower concentrations, combined with the fact that the surface-to-volume ratio increases in direct proportion to the device size decreasing, could create potential problems in device utilization. The problem being that, the analytes or target molecules may be completely non-specifically adsorbed on the surfaces of the microdevices before they reach the detector. Thus, the basic understanding of the adsorption behavior of biomolecules on the surfaces of these systems is critical for their use in microfluidics as well as bioanalytical devices. \r\nWe have developed assays to evaluate protein adsorption under flow and static conditions at submonolayer coverages on poly(ethylene glycol) (PEG)-modified surfaces, which are used for many applications in an attempt to resist or eliminate protein adsorption. Protein adsorption onto PEG-modified microcapillary surfaces, under flow conditions, has been determined at different flow rates as well as various protein concentrations. Alkaline phosphatase and horseradish peroxidase were used to evaluate proteins adsorption behavior at the relatively low concentration range of 10-300 ng/ml, which although low, was still significant. The flow rate was also seen to affect the protein adsorption on the PEG-modified-surfaces at a fixed concentration. We have extended our experimental studies to obtain a saturated (maximum) layer on the PEG-modified surface at a fixed 300 ng/ml, at varied flow rates, in a simulation (model) study for the development of new biocompatible microfluidics systems.