Paper BI1+NS-ThM2
Fabrication of Functional Hydrogel Nano-structures for Biomolecule Immobilization

Thursday, October 21, 2010, 8:20 am, Room Taos

Hydrogels have been used extensively for tissue engineering scaffolds and other biomedical applications because of their unique three-dimensional cross-linked polymer network that provide structural support while endowing an environment similar to natural tissue. Fabrication of hydrogels in submicron scale is greatly desirable; however structures with well-defined organization and high uniformity are not easily achievable by using traditional methods. Herein, we have demonstrated the printing of thiolated PEG hydrogels on a glass chip with precise control over the architecture and feature size using dip-pen nanolithography (DPN) techniques. This direct and reliable method for generating hydrogel patterns may serve as useful tools to explore cell-substrate interactions. In addition, conjugating different proteins through the free thiol functional groups in hydrogels is a promising approach of functionalizing the substrate with different biomolecules. This can be used as a platform for high throughput screening of protein-cell interaction studies. We have shown specific immobilization of thiol-reactive rhodamine red maleimide molecules on to the hydrogel patterns. Yellow-fluorescent was observed exclusively at the patterned area. By adjusting the ratio between the two PEG hydrogel precursors, we should be able to fine-tune the number of free thiol functional groups in the hydrogels, and hence the density of conjugated biomolecules. These hydrogels with different composition can be also printed simultaneously by DPN techniques to create gradient pattern in a single array. In a nutshell, our studies has combined the top-down approach of generating 3D nanostructures surfaces with controlled surface chemistry which creates an ideal interface for solving various fundamental questions in the field of cell biology.