Tyrosinase-mediated Peptide Conjugation with Chitosan-coated Gold Nanoparticles

Abstract

The conjugation of biomolecules, such as protein, sugar, and DNA, with metal nanoparticles is an important technique for bioassay and biomaterial preparation. In this study, we aim to enzymatically immobilize a functional peptide on gold nanoparticles (AuNPs) using a single-step reaction. We used tyrosinase, a catechol oxidase, to immobilize an enzymatic peptide. We performed immobilization experiments of a fluorescent compound-linked caspase-3 substrate peptide using tyrosinase on chitosan-coated AuNPs. Peptides were effectively immobilized onto the AuNPs depending on the presence of tyrosine within the sequence, which suggests the DOPA-quinone produced from tyrosine, via tyrosinase, is connected to the chitosan amino group. Although fluorescent emission from the immobilized capase-3 substrate was quenched by AuNPs, fluorescence intensity recovery occurred due to the addition of caspase-3. Thus, we were able to easily prepare functional AuNPs that can be used for a caspase-3 activity assay. Our results indicate that the tyrosinase-mediated peptide link to chitosan-coated particles is a useful technique for preparing functionalized nanoparticles.

In Vivo Toxicity Studies of Chitosan-Coated Cobalt Ferrite Nanocomplex for Its Application as MRI Contrast Dye

“…Chitosan (CH), a homopolymer of β-(1,4)-linked N -acetyl- d -glucosamine, is one of the biodegradable materials having a range of biological activities such as activation of the immune response, phytoalexin elicitor activities, cholesterol-lowering activity, antihypertension activity, wound-healing properties, neuroprotective activities, and antacid, antibacterial, and antiulcer activities. − Previously, chitosan has been utilized as a coating material in different nanostructure systems including CFN. − Coating of CFN with CH ( i . e ., chitosan-coated cobalt ferrite nanoparticle (CCN)) reduced the cytotoxic potential by inhibiting surface oxidation .…”

Protein-Functionalized Gold Nanoparticles for Antibody Detection Using the Darkfield Microscopic Observation of Nanoparticle Aggregation

“…Nanoparticles (NPs), especially gold nanoparticles (AuNPs), are ideal substrates for biosensing assays and biomedical applications because of their unique properties such as high dispersibility in water, facile synthesis, tunability of morphology and size, and chemical modulation of surface functionalities 1,2 . AuNPs can be synthesized and modified with various chemical functional groups that facilitate the conjugation of low-molecular weight ligands, polymers, peptides, proteins, and DNAs with the NPs [3][4][5][6][7] . This conjugation ability imparts stability, functionality, and biocompatibility to the functionalized AuNPs, thus widening their application scope in bioanalysis and biotechnology.…”

Biomedical Applications of Iron Oxide Nanoparticles: Current Insights Progress and Perspectives

“…This involves capping SPIONs with organic acids (citric acid [42] and oleic acid [43,44]) or coating them with biocompatible hydrophilic polymers (poly(ethylene glycol) (PEG) [45][46][47][48][49] poly(vinyl alcohol) (PVA) [50,51], polyvinyl pyrrolidine (PVP) [52], polysaccharides, such as chitosan or dextran [53][54][55][56], while noncoated SPIONs have a tendency to aggregate in the bloodstream after intravenous injection. PEG-SPIONs show prolonged half-life time of SPIONs and reduce their cellular uptake.…”