title: Electrical detection of nucleic acid amplification using an on-chip quasi-reference electrode and a PVC REFET.
abstract: Electrical detection of nucleic acid amplification through pH changes associated with nucleotide addition enables miniaturization, greater portability of testing apparatus, and reduced costs. However, current ion-sensitive field effect transistor methods for sensing nucleic acid amplification rely on establishing the fluid gate potential with a bulky, difficult to microfabricate reference electrode that limits the potential for massively parallel reaction detection. Here we demonstrate a novel method of utilizing a microfabricated solid-state quasi-reference electrode (QRE) paired with a pH-insensitive reference field effect transistor (REFET) for detection of real-time pH changes. The end result is a 0.18 μm, silicon-on-insulator, foundry-fabricated sensor that utilizes a platinum QRE to establish a pH-sensitive fluid gate potential and a PVC membrane REFET to enable pH detection of loop mediated isothermal amplification (LAMP). This technique is highly amendable to commercial scale-up, reduces the packaging and fabrication requirements for ISFET pH detection, and enables massively parallel droplet interrogation for applications, such as monitoring reaction progression in digital PCR.
authors.affiliation: Department of Bioengineering, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
authors.forename: Eric
authors.initials: E
authors.lastname: Salm
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhong
authors.forename: Bobby
authors.initials: B
authors.lastname: Reddy
authors.forename: Carlos
authors.initials: C
authors.lastname: Duarte-Guevara
authors.forename: Vikhram
authors.initials: V
authors.lastname: Swaminathan
authors.forename: Yi-Shao
authors.initials: YS
authors.lastname: Liu
authors.forename: Rashid
authors.initials: R
authors.lastname: Bashir
mesh_terms: D004566:Electrodes; D004867:Equipment Design; D006863:Hydrogen-Ion Concentration; D055616:Microtechnology; D021141:Nucleic Acid Amplification Techniques / Q000295:instrumentation* / Q000379:methods*; D020411:Oligonucleotide Array Sequence Analysis / Q000295:instrumentation; D010984:Platinum; D016133:Polymerase Chain Reaction / Q000379:methods; D011143:Polyvinyl Chloride
chemical_list: D010984:Platinum; D011143:Polyvinyl Chloride