title: "Stable-on-the-Table" Biosensors: Hemoglobin-Poly (Acrylic Acid) Nanogel BioElectrodes with High Thermal Stability and Enhanced Electroactivity.
abstract: In our efforts toward producing environmentally responsible but highly stable bioelectrodes with high electroactivities, we report here a simple, inexpensive, autoclavable high sensitivity biosensor based on enzyme-polymer nanogels. Met-hemoglobin (Hb) is stabilized by wrapping it in high molecular weight poly(acrylic acid) (PAA, M(W) 450k), and the resulting nanogels abbreviated as Hb-PAA-450k, withstood exposure to high temperatures for extended periods under steam sterilization conditions (122 °C, 10 min, 17-20 psi) without loss of Hb structure or its peroxidase-like activities. The bioelectrodes prepared by coating Hb-PAA-450k nanogels on glassy carbon showed well-defined quasi-reversible redox peaks at -0.279 and -0.334 V in cyclic voltammetry (CV) and retained >95% electroactivity after storing for 14 days at room temperature. Similarly, the bioelectrode showed ~90% retention in electrochemical properties after autoclaving under steam sterilization conditions. The ultra stable bioelectrode was used to detect hydrogen peroxide and demonstrated an excellent detection limit of 0.5 μM, the best among the Hb-based electrochemical biosensors. This is the first electrochemical demonstration of steam-sterilizable, storable, modular bioelectrode that undergoes reversible-thermal denaturation and retains electroactivity for protein based electrochemical applications.
authors.affiliation: Department of Chemistry, University of Connecticut, Storrs, CT 06269, USA. ananta.ghimire@uconn.edu.
authors.forename: Ananta
authors.initials: A
authors.lastname: Ghimire
authors.affiliation: Department of Chemistry, University of Connecticut, Storrs, CT 06269, USA. omkar.zore@uconn.edu.
authors.forename: Omkar V
authors.initials: OV
authors.lastname: Zore
authors.affiliation: Department of Chemistry, University of Connecticut, Storrs, CT 06269, USA. vindyakalani@gmail.com.
authors.forename: Vindya K
authors.initials: VK
authors.lastname: Thilakarathne
authors.affiliation: Department of Chemistry, University of Connecticut, Storrs, CT 06269, USA. victoria.briand@gmail.com.
authors.forename: Victoria A
authors.initials: VA
authors.lastname: Briand
authors.affiliation: Department of Molecular and Cell Biology, University of Connecticut Storrs, Storrs, CT 06269, USA. patrick.lenehan@uconn.edu.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Lenehan
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Connecticut, Storrs, CT 06269, USA. ylei@engr.uconn.edu.
authors.forename: Yu
authors.initials: Y
authors.lastname: Lei
authors.affiliation: Department of Chemistry, University of Connecticut, Storrs, CT 06269, USA. kasi@uconn.edu.|Institute of Materials Science, U-3136, University of Connecticut, Storrs, CT 06269, USA. kasi@uconn.edu.
authors.forename: Rajeswari M
authors.initials: RM
authors.lastname: Kasi
authors.affiliation: Department of Chemistry, University of Connecticut, Storrs, CT 06269, USA. challa.kumar@uconn.edu.|Institute of Materials Science, U-3136, University of Connecticut, Storrs, CT 06269, USA. challa.kumar@uconn.edu.|Department of Molecular and Cell Biology, University of Connecticut Storrs, Storrs, CT 06269, USA. challa.kumar@uconn.edu.
authors.forename: Challa V
authors.initials: CV
authors.lastname: Kumar
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D002417:Cattle; D000067493:Dynamic Light Scattering; D055664:Electrochemical Techniques; D004566:Electrodes; D004587:Electrophoresis, Agar Gel; D004602:Elements; D006454:Hemoglobins / Q000032:analysis* / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000032:analysis; D007700:Kinetics; D046529:Microscopy, Electron, Transmission; D000080385:Nanogels; D009195:Peroxidase / Q000378:metabolism; D011092:Polyethylene Glycols / Q000737:chemistry*; D011094:Polyethyleneimine / Q000737:chemistry*; D011489:Protein Denaturation; D013227:Steam; D013242:Sterilization; D013696:Temperature; D013997:Time Factors
chemical_list: D000180:Acrylic Resins; D004602:Elements; D006454:Hemoglobins; D000080385:Nanogels; D013227:Steam; C413692:polyethylene glycol polyethyleneimine nanogel; D011092:Polyethylene Glycols; C006903:carbopol 940; D011094:Polyethyleneimine; D006861:Hydrogen Peroxide; D009195:Peroxidase
keywords: biocatalysis; electrochemistry; hemoglobin; high temperature catalysis; polyacrylic acid; steam sterilization