J. Phys. Chem. B, 111 (50), 14022 -14027, 2007. 10.1021/jp075909j S1520-6106(07)05909-3
Web Release Date: November 29, 2007

Copyright © 2007 American Chemical Society

Evaluation of Enzymatic Activity on Nanoscale Polystyrene-block-Polymethylmethacrylate Diblock Copolymer Domains

Omkar Parajuli, Abhishek Gupta, Nitin Kumar, and Jong-in Hahm*

Department of Chemical Engineering, The Pennsylvania State University, 160 Fenske Laboratory, University Park, Pennsylvania 16802

Received: July 26, 2007

In Final Form: October 5, 2007

Abstract:

Understanding structural and functional changes of polymeric surface-bound proteins is extremely important as polymers play an increasingly significant role as arrays and substrates in proteomics applications. We carried out, for the first time, quantitative activity measurements of horseradish peroxidase (HRP) enzymes immobilized selectively on the polystyrene domains of microphase-separated polystyrene-block-polymethylmethacrylate ultrathin films. The specific enzymatic activity of HRP adsorbed on the diblock copolymer surface was evaluated and compared to that of HRP in free solution. We demonstrate that the polymeric surface-bound HRP molecules maintain approximately 85% of their activity in free solution. The unique advantages of diblock copolymer templates, involving nanoscale self-assembly and largely retained protein functionality, make the spontaneously constructed enzyme nanoarrays highly suitable as proteomics substrates. Our novel assembly method of providing functional enzymes on diblock copolymer thin films can be greatly beneficial for high-throughput and high-density protein assays.


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