Fabrication and testing of a microneedles sensor array for p-cresol detection with potential biofuel applications.
We present a miniaturized high-throughput sensor array that will augment biofuel technology by facilitating in situ biochemical measurements upon micrometer-scale surfaces of leaves, stems, or petals. We used semiconductor processing to photopattern Foturan glass wafers and fabricated gold-plated microscopic electrode needles (ElectroNeedles) that pierced 125-mum-thick surfaces without deformation. The 5 x 5 or 10 x 10 arrays of ElectroNeedles can analyze 25 or 100 samples simultaneously, increasing throughput. Each microneedle in the array can also be individually addressed and selectively functionalized using diazonium electrodeposition, conferring multiplexing capability. Our microfabrication is a simple, inexpensive, and rapid alternative to the time-, cost-, and protocol-intense, deep-reactive-ion-etching Bosch process. We validated the system performance by electrochemically detecting p-cresol, a phenolic substrate for laccase, an enzyme that is implicated in lignin degradation and therefore important to biofuels. Our limits of detection (LOD) and quantization (LOQ) for p-cresol were 1.8 and 16microM, respectively, rivaling fluorescence detection (LOD and LOQ = 0.4 and 3microM, respectively). ElectroNeedles are multiplexed, high-throughput, chip-based sensor arrays designed for minimally invasive penetration of plant surfaces, enabling in situ and point-of-test analyses of biofuel-related biochemicals.
Harper
Jason C
JC
Sandia National Laboratories, Albuquerque, New Mexico 87185, Life Bioscience, Albuquerque, New Mexico 87185, USA.
Brozik
Susan M
SM
Flemming
Jeb H
JH
McClain
Jaime L
JL
Polsky
Ronen
R
Raj
Dominic
D
Ten Eyck
Gregory A
GA
Wheeler
David R
DR
Achyuthan
Komandoor E
KE
D056804:Biofuels; D002138:Calibration; D003408:Cresols / Q000737:chemistry*; D003979:Diazonium Compounds / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004563:Electrochemistry / Q000379:methods; D005453:Fluorescence; D005456:Fluorescent Dyes; D005947:Glucose / Q000737:chemistry; D042845:Laccase / Q000737:chemistry; D008422:Materials Testing; D009339:Needles
D056804:Biofuels; D003408:Cresols; D003979:Diazonium Compounds; D005456:Fluorescent Dyes; C032538:4-cresol; D042845:Laccase; D005947:Glucose