Thiol-ene radical coupling is increasingly used for the biofunctionalization of biomaterials. Thiol-ene chemistry presents interesting features that are particularly attractive for platforms requiring specific reactions with peptides or proteins and the patterning of cells, such as reactivity in physiological conditions and photoactivation. In this work, we synthesized alkene-functionalized (allyl and norbornene residues) antifouling polymer brushes (based on poly(oligoethylene glycol methacrylate)) and studied thiol-ene coupling with a series of thiols including cell adhesive peptides RGD and REDV. The adhesion of umbilical vein endothelial cells (HUVECs) to these interfaces was studied and highlighted the absence of specific integrin engagement to REDV, in contrast to the high level of cell spreading observed on RGD-functionalized polymer brushes. This revealed that α4β1 integrins (binding to REDV sequences) are not sufficient on their own to sustain HUVEC spreading, in contrast to αvβ3 and α5β1 integrins. In addition, we photopatterned peptides at the surface of poly(oligoethylene glycol methacrylate) (POEGMA) brushes and characterized the quality of the resulting arrays by epifluorescence microscopy and atomic force microscopy (AFM). This allowed the formation of cell patterns and demonstrated the potential of thiol-ene based photopatterning for the design of cell microarrays.