(13d) Hydrogel Based Protein Recognitive Systems for Diagnostic Applications

Protein imprinting is an emerging field of interest in which a polymer network is formed with specific recognition for a desired template molecule. Briefly, functional monomers are allowed to complex with the template, polymerized in the presence of this molecule, the template is subsequently removed, and the product is a polymer with binding sites specific to the protein template.

The objective of this research is to develop biomimetic recognitive hydrogel polymer networks that can be applied to biosensing or other nanoscale applications. Towards this goal, we aim to integrate recognitive hydrogels with ultrasensitive microcantilever transducers, for the first time, which can be used to detect low concentration protein biomarkers in a simple, inexpensive, and robust manner.

Protein recognitive hydrogels were synthesized via a thermal free radical polymerization of methacrylic acid (MAA), acrylamide (Aam), and 2-(dimethylamino)ethyl methacrylate (DMAEMA) grafted with polyethylene glycol (400) dimethacrylate as the crosslinker. Bovine serum albumin (BSA) was used as the model protein template. Electrostatic interactions are exploited between the charged functional monomers MAA and DMAEMA and the corresponding oppositely charged amino acids present in BSA. In addition, BSA contains polar, uncharged amino acids that can undergo hydrogen bonding with Aam.

We have demonstrated the ability to consistently remove BSA, 70-97%, at amounts near and above values in literature. Initial recognition studies have shown that the synthesized protein imprinted polymers have BSA recognition capabilities as 8.8 times more BSA was absorbed by the imprinted (13.8+/-4.5 mg) compared to that of the control sample (1.6+/-1.1mg). Selectivity studies are underway which have shown the potential for the proposed system to recognize BSA in a solution of similar proteins.

In addition, preliminary hydrogel coated microcantilever deflection measurements have been conducted and quantified optically. This deflection was calibrated to yield a corresponding concentration of the protein template molecule.