Bioinspired surface modification of poly(2-hydroxyethyl methacrylate) based microbeads via oxidative polymerization of dopamine

• Bioinspired surface modification of polymers via direct polymerization of dopamine.
• The catechol functional groups of dopamine have the ability to form strong adhesive bonds.
• Polydopamine plays essential role in adhesion both onto the microbeads and analyte biomolecules.
• IgG adsorption capacities increased from 3.71 mg/g to 74.21 mg/g with dopamine modification.
• Monolayer Langmuir adsorption model can be thought more applicable for this adsorbent systems.

Surface modification of support materials is crucial for improving their selectivities and biocompatibilities in bioaffinity applications. However, conventional modification techniques including chemical or physical conjugations mostly suffer from limitations of their multistep and complicated procedures, surface denaturations, batch-to-batch inconsistencies, and insufficient surface conjugations. In this study, we demonstrate a simple yet effective bioinspired approach for the surface modification of poly(2-hydroxyethyl methacrylate) [PHEMA] based bioaffinity adsorbents through oxidative polymerization of dopamine. The magnetic (mPHEMA) and non-magnetic (PHEMA) polymeric microbeads were fabricated by suspension polymerization technique. Surface modification of obtained microbeads was then carried out by using dopamine molecules under alkaline conditions. The polydopamine (PDOPA) coated microbeads were further employed as a bioaffinity absorbent targeted for immunoglobulin G (IgG) molecules. The effects of pH, temperature, protein concentration and ionic strength on the IgG adsorption process have been investigated. We found that PDOPA coated microbeads display dramatically higher IgG adsorption capacities when compared with their un-modified forms. Adsorption capacities also increased with increasing temperature. Monolayer Langmuir adsorption model can be thought more applicable for these adsorbent systems.

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