title: Real-time evaluation of macromolecular surface modified quartz crystal resonant sensors under cryogenic stress for biological applications.
abstract: This study presents a novel auto-gain-control based quartz acoustic sensor technology capable of constant quartz crystal operation when cycled between ambient (22 degrees C) and cryogenic temperatures (-196 degrees C), afforded by direct exposure of crystals to bulk liquid nitrogen. The real-time frequency response profiles due to freeze-thaw cycling on crystals of differing surface finish and two model macromolecular surface coatings were studied in order to determine surface events such as water uptake. The quartz crystal surface finishes used were optically polished or lapped to one of two surface finishes. These were used as control native gold electrodes, and these surfaces were further coated with bovine serum albumin or the tri-block copolymer, poloxamer-188 as model macromolecular surface architectures. Crystals were snap frozen in liquid nitrogen and allowed to return to ambient temperature under controlled conditions. The processes of ice formation, thawing and evaporation were followed in real-time and comparisons were made between the test samples in order to assess the capability of this technique for sensing changes in surface characteristics such as the entrapment of water.
authors.affiliation: Acoustic Sensors Research Group, School of Pharmacy and Biomolecular Sciences, Cockcroft Building, University of Brighton, Lewes Road, Brighton, East Sussex BN2 4GJ, UK. k.d.pavey@bton.ac.uk
authors.forename: Karl D
authors.initials: KD
authors.lastname: Pavey
authors.forename: A Christy
authors.initials: AC
authors.lastname: Hunter
authors.forename: Frank
authors.initials: F
authors.lastname: Paul
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis*; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005615:Freezing; D006046:Gold; D046911:Macromolecular Substances; D009862:Online Systems; D011791:Quartz / Q000737:chemistry* / Q000528:radiation effects*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013499:Surface Properties; D014159:Transducers; D014867:Water / Q000032:analysis*
chemical_list: D020099:Coated Materials, Biocompatible; D046911:Macromolecular Substances; D014867:Water; D011791:Quartz; D006046:Gold