title: Hard and soft micro- and nanofabrication: An integrated approach to hydrogel-based biosensing and drug delivery.
abstract: We review efforts to produce microfabricated glucose sensors and closed-loop insulin delivery systems. These devices function due to the swelling and shrinking of glucose-sensitive microgels that are incorporated into silicon-based microdevices. The glucose response of the hydrogel is due to incorporated phenylboronic acid (PBA) side chains. It is shown that in the presence of glucose, these polymers alter their swelling properties, either by ionization or by formation of glucose-mediated reversible crosslinks. Swelling pressures impinge on microdevice structures, leading either to a change in resonant frequency of a microcircuit, or valving action. Potential areas for future development and improvement are described. Finally, an asymmetric nano-microporous membrane, which may be integrated with the glucose-sensitive devices, is described. This membrane, formed using photolithography and block polymer assembly techniques, can be functionalized to enhance its biocompatibility and solute size selectivity. The work described here features the interplay of design considerations at the supramolecular, nano, and micro scales.
authors.affiliation: Department of Pharmaceutics, University of Minnesota, Minneapolis, MN 55455, USA. siege017@umn.edu
authors.forename: Ronald A
authors.initials: RA
authors.lastname: Siegel
authors.forename: Yuandong
authors.initials: Y
authors.lastname: Gu
authors.forename: Ming
authors.initials: M
authors.lastname: Lei
authors.forename: Antonio
authors.initials: A
authors.lastname: Baldi
authors.forename: Eric E
authors.initials: EE
authors.lastname: Nuxoll
authors.forename: Babak
authors.initials: B
authors.lastname: Ziaie
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D016503:Drug Delivery Systems / Q000295:instrumentation*; D004867:Equipment Design; D005947:Glucose / Q000737:chemistry; D006244:Hardness; D020100:Hydrogels / Q000737:chemistry*; D007332:Insulin Infusion Systems; D036103:Nanotechnology; D011108:Polymers / Q000737:chemistry; D013678:Technology, Pharmaceutical
chemical_list: D020100:Hydrogels; D011108:Polymers; D005947:Glucose