Protein patterning on microtextured polymeric nano-brush templates obtained by nanosecond fibre laser Meenakshi Verma and Sampa Saha IIT Delhi, India Micropatterned polymer brushes have attracted attention in several areas of biomedical science, i.e., tissue engineering, protein microarray, biosensors etc., for precise arrangement of biomolecules. Herein, we report a facile and scalable approach to create microtextured biocompatible and biofunctional polymer brushes with the ability to generate different type of protein patterns (e.g., line and circular). Nanosecond fibre laser was employed to generate around 30 micron wide patterns on the polymer brush (poly(ethylene glycol) methacrylate (polyPEGMA), a protein repellent brush) modified Ti alloy based substrate. PolyPEGMA brush of varying thickness (11-87 nm, measured by ellipsometry) was grafted on Ti alloy via surface initiated atom transfer radical polymerisation (SIATRP) using chloro functionalized ATRP initiator immobilized on Ti surface with initiator density (σ*) of 1.5 initiators/nm 2 . Polymer brushes were then selectively laser ablated and their presence on non- textured area of the laser processed template was primarily confirmed by atomic force microscopy, fluorescence microscopy and X-ray Photoelectron spectroscopy. Spatial orientation of biomolecules was first achieved by non-specific protein adsorption on areas ablated by the laser, via physisorption. Further, patterned brushes of polyPEGMA were modified to activated ester that gave rise to protein conjugation specifically on non-laser ablated brush areas observed via fluorescence microscope and FESEM. Moreover, the laser ablated brush modified template forming alternate patterns was also demonstrated for generating alternate patterns of bacteria such as E. coli as observed via optical microscopy. This promising technique can be further extended to create interesting patterns of several biomolecules which are of great interest to biomedical research community. References 1. Verma, M., Rana, A., Vidyasagar, K.E.C., Kalyanasundaram, D. and Saha, S. (2022), Protein Patterning on Microtextured Polymeric Nanobrush Templates Obtained by Nanosecond Fiber Laser. Macromol. Biosci., 22: 2100454.
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