title: Transient deflection response in microcantilever array integrated with polydimethylsiloxane (PDMS) microfluidics.
abstract: We report the integration of a nanomechanical sensor consisting of 16 silicon microcantilevers with polydimethylsiloxane (PDMS) microfluidics. For microcantilevers positioned near the bottom of a microfluidic flow channel, a transient differential analyte concentration for the top versus bottom surface of each microcantilever is created when an analyte-bearing fluid is introduced into the flow channel (which is initially filled with a non-analyte containing solution). We use this effect to characterize a bare (nonfunctionalized) microcantilever array in which the microcantilevers are simultaneously read out with our recently developed high sensitivity in-plane photonic transduction method. We first examine the case of non-specific binding of bovine serum albumin (BSA) to silicon. The average maximum transient microcantilever deflection in the array is -1.6 nm, which corresponds to a differential surface stress of only -0.23 mN m(-1). This is in excellent agreement with the maximum differential surface stress calculated based on a modified rate equation in conjunction with finite element simulation. Following BSA adsorption, buffer solutions with different pH are introduced to further study microcantilever array transient response. Deflections of 20-100 nm are observed (2-14 mN m(-1) differential surface stress). At a flow rate of 5 μL min(-1), the average measured temporal width (FWHM) of the transient response is 5.3 s for BSA non-specific binding and 0.74 s for pH changes.
authors.affiliation: Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT 84602, USA.
authors.forename: Ryan R
authors.initials: RR
authors.lastname: Anderson
authors.forename: Weisheng
authors.initials: W
authors.lastname: Hu
authors.forename: Jong Wook
authors.initials: JW
authors.lastname: Noh
authors.forename: William C
authors.initials: WC
authors.lastname: Dahlquist
authors.forename: Stanley J
authors.initials: SJ
authors.lastname: Ness
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Gustafson
authors.forename: Danny C
authors.initials: DC
authors.lastname: Richards
authors.forename: Seunghyun
authors.initials: S
authors.lastname: Kim
authors.forename: Brian A
authors.initials: BA
authors.lastname: Mazzeo
authors.forename: Adam T
authors.initials: AT
authors.lastname: Woolley
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Nordin
mesh_terms: D000818:Animals; D002417:Cattle; D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D044085:Microfluidics / Q000295:instrumentation* / Q000379:methods; D011485:Protein Binding; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000378:metabolism*; D012825:Silicon / Q000737:chemistry* / Q000378:metabolism
chemical_list: D004129:Dimethylpolysiloxanes; D012710:Serum Albumin, Bovine; D012825:Silicon