Ultrasensitive biomens sensors based on microcantilevers patterned with environmentally responsive hydrogels

J. Zachary Hilt, Amit K. Gupta, Rashid Bashir, Nicholas A. Peppas

Research output: Contribution to journalArticlepeer-review

Abstract

An innovative platform was developed for ultrasensitive microsensors based on microcantilevers patterned with crosslinked copolymeric hydrogels. A novel UV free-radical photolithography process was utilized to precisely align and pattern environmentally responsive hydrogels onto silicon microcantilevers, after microcantilevers were fabricated and released. Specifically, a crosslinked poly(methacrylic acid) network containing high amounts of poly(ethylene glycol) dimethacrylate was prepared and investigated. Hydrogels were patterned onto the silicon microcantilevers utilizing a mask aligner to allow for precise positioning. The silicon surface was modified with γ-methacryloxypropyl trimethoxysilane to gain covalent adhesion between the polymer and the silicon. The hydrogels sensed and responded to changes in environmental pH resulting in a variation in surface stress that deflected the microcantilever. The bending response of patterned cantilevers with a change in environmental pH was observed, showing the possibility to construct MEMS/BioMEMS sensors based on microcantilevers patterned with environmentally responsive hydrogels. An extraordinary maximum sensitivity of 1 nm/5 × 10-5 ΔpH was observed, demonstrating the ultrasensitivity of this microsensor platform.

Original languageEnglish (US)
Pages (from-to)177-184
Number of pages8
JournalBiomedical microdevices
Volume5
Issue number3
DOIs
StatePublished - Sep 1 2003
Externally publishedYes

Keywords

  • BioMEMS
  • Free-radical photopolymerization
  • Hydrogel
  • MEMS
  • Microcantilever
  • Micropatterning
  • Microsensor
  • pH sensor

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Genetics
  • Neuroscience(all)

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