title: Preparation of photolithographically patterned inverse opal hydrogel microstructures and its application to protein patterning.
abstract: Protein pattern has played an important role in biosensors, bioMEMS, tissue engineering, fundamental studies of cell biology, and basic proteomics research. Here, we developed a straightforward and effective protein patterning technique using macroporous poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogel micropatterns as a three-dimensional (3D) template for protein immobilization. Micropatterns of macroporous hydrogels with inverse opal structures were prepared on poly(ethylene glycol) (PEG)-coated silicon substrates by combining a colloidal crystal templating method with photopatterning. The resultant inverse opal hydrogel (IOH) micropatterns were modified with 3-aminopropyltriethoxysilane using the hydroxyl groups in PHEMA for the covalent immobilization of proteins. Proteins were selectively immobilized only on the hydrogel micropatterns, while the PEG regions served as an effective barrier to protein adsorption. Because of their highly ordered and interconnected 3D macroporous structures and large internal surface areas, protein loading in the IOH micropattern was about six times greater than that on a non-porous hydrogel micropattern, which consequently improved the protein activity. The porosity of the hydrogel micropatterns could be controlled using different sizes of colloidal nanoparticles, and using smaller nanoparticles produced hydrogel micropatterns with higher protein loading capacities and activities. To demonstrate the potential use of IOH micropatterns in biosensor systems, biotin was micropatterned on the hydrogels and the specific binding of streptavidin was successfully assayed using IOH micropatterns with better fluorescence signals and sensitivity than that of the corresponding non-porous hydrogel micropatterns.
authors.affiliation: Department of Chemical and Biomolecular Engineering, Yonsei University, 134 Sinchon-Dong, Seodaemoon-Gu, Seoul 120-749, Republic of Korea.
authors.forename: Yeongmin
authors.initials: Y
authors.lastname: Lee
authors.affiliation: Department of Chemical and Biomolecular Engineering, Yonsei University, 134 Sinchon-Dong, Seodaemoon-Gu, Seoul 120-749, Republic of Korea.
authors.forename: Sangphil
authors.initials: S
authors.lastname: Park
authors.affiliation: Department of Chemical and Biomolecular Engineering, Yonsei University, 134 Sinchon-Dong, Seodaemoon-Gu, Seoul 120-749, Republic of Korea.
authors.forename: Sang Won
authors.initials: SW
authors.lastname: Han
authors.affiliation: Department of Chemical and Biomolecular Engineering, Yonsei University, 134 Sinchon-Dong, Seodaemoon-Gu, Seoul 120-749, Republic of Korea.
authors.forename: Tae Geuk
authors.initials: TG
authors.lastname: Lim
authors.affiliation: Department of Chemical and Biomolecular Engineering, Yonsei University, 134 Sinchon-Dong, Seodaemoon-Gu, Seoul 120-749, Republic of Korea. Electronic address: wongun@yonsei.ac.kr.
authors.forename: Won-Gun
authors.initials: WG
authors.lastname: Koh
mesh_terms: D001672:Biocompatible Materials; D015374:Biosensing Techniques / Q000379:methods*; D001710:Biotin; D020100:Hydrogels; D055767:Immobilized Proteins; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles; D011102:Polyhydroxyethyl Methacrylate; D016062:Porosity; D019809:Streptavidin; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D020100:Hydrogels; D055767:Immobilized Proteins; D011102:Polyhydroxyethyl Methacrylate; D001710:Biotin; D019809:Streptavidin