title: Characterization of Lactate Sensors Based on Lactate Oxidase and Palladium Benzoporphyrin Immobilized in Hydrogels.
abstract: An optical biosensor for lactate detection is described. By encapsulating enzyme-phosphor sensing molecules within permeable hydrogel materials, lactate-sensitive emission lifetimes were achieved. The relative amount of monomer was varied to compare three homo- and co-polymer materials: poly(2-hydroxyethyl methacrylate) (pHEMA) and two copolymers of pHEMA and poly(acrylamide) (pAam). Diffusion analysis demonstrated the ability to control lactate transport by varying the hydrogel composition, while having a minimal effect on oxygen diffusion. Sensors displayed the desired dose-variable response to lactate challenges, highlighting the tunable, diffusion-controlled nature of the sensing platform. Short-term repeated exposure tests revealed enhanced stability for sensors comprising hydrogels with acrylamide additives; after an initial "break-in" period, signal retention was 100% for 15 repeated cycles. Finally, because this study describes the modification of a previously developed glucose sensor for lactate analysis, it demonstrates the potential for mix-and-match enzyme-phosphor-hydrogel sensing for use in future multi-analyte sensors.
authors.affiliation: Department of Biomedical Engineering, 5045 Emerging Technologies Building, 3120 TAMU, Texas A&M University, College Station, TX 77843, USA. lpa6@tamu.edu.
authors.forename: Liam P
authors.initials: LP
authors.lastname: Andrus
authors.affiliation: Department of Biomedical Engineering, 5045 Emerging Technologies Building, 3120 TAMU, Texas A&M University, College Station, TX 77843, USA. rachel_unruh@tamu.edu.
authors.forename: Rachel
authors.initials: R
authors.lastname: Unruh
authors.affiliation: PROFUSA, Inc., 345 Allerton Avenue, South San Francisco, CA 94080, USA. natalie.wisniewski@profusa.com.
authors.forename: Natalie A
authors.initials: NA
authors.lastname: Wisniewski
authors.affiliation: Department of Biomedical Engineering, 5045 Emerging Technologies Building, 3120 TAMU, Texas A&M University, College Station, TX 77843, USA. mcshane@tamu.edu.|Department of Materials Science and Engineering, 3003 TAMU, Texas A&M University, College Station, TX 77843, USA. mcshane@tamu.edu.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: McShane
mesh_terms: D015374:Biosensing Techniques; D004058:Diffusion; D004800:Enzymes, Immobilized; D020100:Hydrogels / Q000737:chemistry*; D019344:Lactic Acid / Q000737:chemistry*; D006899:Mixed Function Oxygenases / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry*
chemical_list: D004800:Enzymes, Immobilized; D020100:Hydrogels; D011166:Porphyrins; D019344:Lactic Acid; D010165:Palladium; D006899:Mixed Function Oxygenases; C021497:lactate 2-monooxygenase
keywords: biosensor; enzyme; hydrogel; lactate; luminescence