Versatile Functionalization Of The Micro-patterned Hydrogel Of Hyperbranched Poly (Ether Amine) Based On The Thiol-Yne Chemistry

Patterned hydrogel has been widely used in biochip，drug release,tissue engineering, Chemical switch. Hydrogel is a kind of promisingmaterial and finds the potential application in fields of biomedical devicesand tissue engineering. In particular, the patterned hydrogel of large-scalecan be used for microarray of protein and controlled alignment of cell, andhas become of great interest in the past few years.The hydrogel can be provided with the different functions throughcovalently bonding target molecules, which has become very useful in avariety of applications. Different techniques such as soft-lithography,photolithography, nano-imprinting and electron-beam lithography havebeen developed to fabricate the patterned hydrogel in micro&nano-scale.Among these established methods, photolithography was most widely usedfor fabrication of the patterned hydrogel because of advantages such aslarge-scale production in industry and simple process. To obtain a novelpatterned hydrogel with characters of easy preparation and facilefunctionalization, we here demonstrated a versatile approach tofunctionalize the micro-patterned hydrogel, which was formed by the“thiol-yne” photo-click reaction between the yne-ended hyperbranchedpoly (ether amine)(hPEA-yne) and thiol-containing polyhedral oligomericsilsesquioxane (PEG-POSS-SH). By controlling the molar ratio between hPEA-yne and PEG-POSS-SH, hydrogels containing thiol or yne groupswere obtained. We demonstrated the patterned hydrogels with the residuethiol or yne groups can be functionalized through a variety of thiol or yne-based click reactions. A series of thiol-click chemistry such as “thiol-epoxy”,“thiol-halogen”,“thiol-ene” and “thiol-isocyanate”, were used tofunctionalize the thiol-containing hydrogel (Gel-1); while the yne-containing hydrogel (Gel-2) was functionalized through the typical copper-catalyzed alkyne-azide reaction (CuAAC).FT-IR, UV-vis spectra and confocal laser scanning microscopy(CLSM) were used to traced these click reactions. Due to the selectiveadsorption to the hydrophilic dyes, the obtained patterned hydrogel ofhPEA modified with fluorescent dye was further demonstrated inapplication for recognition of guest molecules.