title: Chemically glycosylation improves the stability of an amperometric horseradish peroxidase biosensor.
abstract: We constructed a biosensor by electrodeposition of gold nano-particles (AuNPs) on glassy carbon (GC) and subsequent formation of a 4-mercaptobenzoic acid self-assembled monolayer (SAM). The enzyme horseradish peroxidase (HRP) was then covalently immobilized onto the SAM. Two forms of HRP were employed: non-modified and chemically glycosylated with lactose. Circular dichroism (CD) spectra showed that chemical glycosylation did neither change the tertiary structure of HRP nor the heme environment. The highest sensitivity of the biosensor to hydroquinone was obtained for the biosensor with HRP-lactose (414 nA μM(-1)) compared to 378 nA μM(-1) for the one employing non-modified HRP. The chemically glycosylated form of the enzyme catalyzed the reduction of hydroquinone more rapidly than the native form of the enzyme. The sensor employing lactose-modified HRP also had a lower limit of detection (74 μM) than the HRP biosensor (83 μM). However, most importantly, chemically glycosylation improved the long-term stability of the biosensor, which retained 60% of its activity over a four-month storage period compared to only 10% for HRP. These results highlight improvements by an innovative stabilization method when compared to previously reported enzyme-based biosensors.
authors.affiliation: Department of Chemistry, University of Puerto Rico, Río Piedras Campus, P.O. Box 23346, San Juan 00931-3346, Puerto Rico. Electronic address: griselle.h.c@gmail.com.
authors.forename: Griselle
authors.initials: G
authors.lastname: Hernández-Cancel
authors.affiliation: Department of Chemistry, University of Puerto Rico, Río Piedras Campus, P.O. Box 23346, San Juan 00931-3346, Puerto Rico. Electronic address: damysuazo@gmail.com.
authors.forename: Damaris
authors.initials: D
authors.lastname: Suazo-Dávila
authors.affiliation: Department of Chemistry, University of Puerto Rico, Río Piedras Campus, P.O. Box 23346, San Juan 00931-3346, Puerto Rico.
authors.forename: Johnsue
authors.initials: J
authors.lastname: Medina-Guzmán
authors.affiliation: Department of Chemistry, University of Puerto Rico, Río Piedras Campus, P.O. Box 23346, San Juan 00931-3346, Puerto Rico. Electronic address: maria.rosado8@upr.edu.
authors.forename: María
authors.initials: M
authors.lastname: Rosado-González
authors.affiliation: Department of Chemistry, University of Puerto Rico, Río Piedras Campus, P.O. Box 23346, San Juan 00931-3346, Puerto Rico. Electronic address: lizvazquez8@gmail.com.
authors.forename: Liz M
authors.initials: LM
authors.lastname: Díaz-Vázquez
authors.affiliation: Department of Chemistry, University of Puerto Rico, Río Piedras Campus, P.O. Box 23346, San Juan 00931-3346, Puerto Rico. Electronic address: kai.griebenow@gmail.com.
authors.forename: Kai
authors.initials: K
authors.lastname: Griebenow
mesh_terms: D015374:Biosensing Techniques; D002942:Circular Dichroism; D004795:Enzyme Stability; D006031:Glycosylation; D006735:Horseradish Peroxidase / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning
chemical_list: D006735:Horseradish Peroxidase
keywords: Biosensor; Glycosylation; Gold nanoparticles; Horseradish peroxidase; Phenolic compound