RT Journal Article SR Electronic T1 Less is More: Oligomer extraction and hydrothermal annealing increase PDMS bonding forces for new microfluidics assembly and for biological studies JF bioRxiv FD Cold Spring Harbor Laboratory SP 150953 DO 10.1101/150953 A1 L. J. Millet A1 A. Jain A1 M. U. Gillette YR 2017 UL http://biorxiv.org/content/early/2017/06/16/150953.abstract AB Key determinants in the emergence of complex cellular morphologies and functions are cues in the micro-environment. Primary among these is the presence of neighboring cells as networks form. Therefore, for high-resolution analysis, it is crucial to develop micro-environments that permit exquisite control of network formation. This is especially true in cell science, tissue engineering, and clinical biology. We introduce a new approach for assembling polydimethylsiloxane (PDMS)-based microfluidic environments that enhances cell network formation and analyses. We report that the combined processes of PDMS solvent-extraction (E-PDMS) and hydrothermal annealing create unique conditions that produce high-strength bonds between E-PDMS and glass – properties not associated with conventional PDMS. Extraction followed by hydrothermal annealing removes unbound oligomers, promotes polymer cross-linking, facilitates covalent bond formation with glass, and retains the highest biocompatibility. Our extraction protocol accelerates oligomer removal from 5 to 2 days. Resulting microfluidic platforms are uniquely suited for cell-network studies owing to high bond strengths, effectively corralling cellular extensions and eliminating harmful oligomers. We demonstrate simple, simultaneous actuation of multiple microfluidic domains for invoking ATP- and glutamate-induced Ca2+ signaling in glial-cell networks. These low-cost, simple E-PMDS modifications and flow manipulations further enable microfluidic technologies for cell-signaling and network studies as well as novel applications.