Fabrication and Verification of Conjugated AuNP-Antibody Nanoprobe for Sensitivity Improvement in Electrochemical Biosensors

Abstract

This study was designed to obtain covalently coupled conjugates as means for achieving higher stability and better coverage of the AuNPs by antibodies on the particle surface suitable for sensor performance enhancement. Starting by using a modified protocol, colloid gold solution, with mean AuNP core size of ~6 nm was synthesized. The protocol used for conjugation of AuNPs to osteocalcin antibody in this study relies on covalent and electrostatic attractions between constituents. Varieties of conjugates with varying combinations of crosslinkers and different concentrations were successfully synthesized. The obtained products were characterized and their properties were studied to determine the best candidate in sense of antibody - antigen reactivity. Using AuNP-GSH-NHS-Ab combination (1:1:1), the tertiary structure of the protein was maintained and thus the antibody remained functional in the future steps. This one-pot method provided a simple method for covalently coupling antibodies on the particle surface while keeping their functionality intact. The AuNP content of the solution also accelerated electron transfer rate and thus amplifies the detection signal. With the developed and discussed technique herein, a simple solution is modeled to be used for measuring serum levels of biomarkers in single and/or multiplexed sensor systems.

Immunogold Nanoparticles for Rapid Plasmonic Detection of C. sakazakii

“…Several novel detection schemes have been proposed that utilize the special properties of the nanometric inorganic particles. In a recent study, gold nanoparticles (NPs) functionalized directly with antibodies used the proximity of the gold NP cores to accelerate the electron transfer rate and consequently amplify the detection signal of the nanoprobe in an electrochemical assay [ 22 ]. Antibody functionalized gold NPs have also been used for the detection of Escherichia coli O157:H7 by using inductively coupled plasma mass spectrometry; this highly sensitive assay was able to detect as few as 500 CFU/mL [ 23 ], but requires advanced equipment and preparation.…”

Gold Nanoparticles in Conjunction with Nucleic Acids as a Modern Molecular System for Cellular Delivery

“…AuNPs are therefore good candidates for in vivo imaging and studies compared to other materials like organic dyes or quantum dots. Taken together, due to the negligible toxicity of gold, and the simplicity of the controlled synthesis of AuNPs and functionalization, it became of interest to utilize AuNPs in conjunction with biomolecules such as nucleic acids [19][20][21], peptides [22], proteins [23,24], antibodies [25,26], and chemotherapeutic agents [27]. An advantage of conjugated AuNPs is improved effectiveness of the active ligands bound to the nanoparticle.…”

Noble Metal Nanostructured Materials for Chemical and Biosensing Systems

“…Noble metal nanomaterials with unique photoelectric properties and good biocompatibility play an important role in chemical and biosensing system [95,96]. Recently, the research on sensing devices of different principles and signals using noble metal nanomaterials have emerged, which provided a new direction for the development of analytical chemistry and sensing technology [97,98].…”