Microfluidic electrochemical glucose biosensor with in situ enzyme immobilizationLokar, Nina (Avtor) Pečar, Borut (Avtor) Možek, Matej (Avtor) Vrtačnik, Danilo (Avtor) microfluidic glucose biosensorelectrochemical biosensorthin film electrodeenzyme in situ immobilizationchronoamperometrycyclic voltammetryThe development and characterization of a microfluidic electrochemical glucose biosensor are presented herein. The transducer part is based on thin-film metal electrodes on a glass substrate. The biological recognition element of the biosensor is the pyrroloquinoline quinone–glucose dehydrogenase (PQQ-GdhB) enzyme, selectively in situ immobilized via microcontact printing of a mixed self-assembling monolayer (SAM) on a gold working electrode, while the microfluidic part of the device comprises microchannel and microfluidic connections formed in a polydimethylsiloxane (PDMS) elastomer. The electrode properties throughout all steps of biosensor construction and the biosensor response to glucose concentration and analyte flow rate were characterized by cyclic voltammetry and chronoamperometry. A measurement range of up to 10 mM in glucose concentration with a linear range up to 200 µM was determined. A detection limit of 30 µM in glucose concentration was obtained. Respective biosensor sensitivities of 0.79 nA/µM/mm$^2$ and 0.61 nA/µM/mm$^2$ were estimated with and without a flow at 20 µL/min. The developed approach of in situ enzyme immobilization can find a wide number of applications in the development of microfluidic biosensors, offering a path towards continuous and time-independent detection.20232024-01-24 15:08:54Članek v reviji154088UDK: 602.1:53.082.9ISSN pri članku: 2079-6374DOI: 10.3390/bios13030364COBISS_ID: 145284355sl