Less is More: A Comparison of Antibody–Gold Nanoparticle Conjugates of Different Ratios

Abstract

This comprehensive study is related to gold nanoparticles (GNPs) conjugated with antibodies. The goal of the study is to determine the minimal concentration of antibodies for conjugate synthesis when the conjugates have high antigen-capturing activity. Two systems were studied: gold nanoparticles conjugated with monoclonal antibodies (mAb-GNP) specific to Helicobacter pylori and gold nanoparticles conjugated with polyclonal antibodies (pAb-GNP) specific to mouse immunoglobulins. Several conjugates were synthesized with different GNP-to-antibody molar ratios (from 1:1 to 1:245) through nondirectional and noncovalent immobilization on a surface of GNPs with a diameter of 25.3 ± 4.6 nm. The maximal antigen-capturing activities and equilibrium constants of the conjugates correlate with the formation of a constant hydrodynamic radius of the conjugates for mAb-GNP (GNP to antibody molar ratio 1:58) and with the stabilizing concentration by flocculation curves for pAb-GNP (GNP to antibody molar ratio 1:116). The application of the conjugates to the lateral flow immunoassay shows that the antibody concentrations used for the conjugation can be reduced (below the stabilizing concentration) without losing activity for the mAb-GNP conjugates. The findings highlight that the optimal concentration of antibodies immobilized on the surface of GNPs is not always equal to the stabilizing concentration determined by the flocculation curve.

Switching of Macromolecular Ligand Display by Thermoresponsive Polymers Mediates Endocytosis of Multiconjugate Nanoparticles

“…Polymer-metal hybrid nanoparticles offer many advantages for diagnosis and therapy, owing to the possibility to endow these materials with multiple functionalities for detecting disease, releasing therapeutic agents or treat the pathology by enhancing externally applied physical stimuli. [1][2][3][4][5][6] However, the clinical applications of nanoparticles in general have been limited by complex and unpredictable pharmacokinetics and targeting. [7][8][9][10] In order to achieve maximal clinical response in vivo any diagnostic or therapeutic agent needs to accumulate at the target tissue and gain access to disease relevant cells and appropriate intracellular compartments.…”

Collagen-based scaffolds with infused anti-VEGF release system as potential cornea substitute for high-risk keratoplasty: An in vitro evaluation

“…A higher red shift in the wavelength of the absorption spectra for GNPs@Bevacizumab conjugated species is observed in comparison to the bare GNPs. High concentration of NaCl disrupts the electrical double layer between the particles and induces a shift in the equilibrium between electrostatic repulsion and attraction 23. Also, there is an increment in the hydrodynamic diameter of the surface modified GNPs in presence of high salt concentration which further validates to efficient conjugation of GNPs and bevacizumab(Figure 2(e)).…”

Refined construction of antibody-targeted nanoparticles leads to superior antigen binding and enhanced delivery of an entrapped payload to pancreatic cancer cells

“…In formulations containing antibodies as the targeting moiety, most approaches have employed the full immunoglobulin molecule, which enhances the diameter of the nanoparticles and can lead to significant surface crowding that may adversely affect stability and impair target binding through steric hindrance effects. 11,12 Moreover, the Fc domain of a fully intact immunoglobulin is susceptible to immune clearance mechanisms, which can markedly reduce the circulation half-life of nanoparticles. 13 To overcome some of these drawbacks, researchers have begun to explore the use of antibody fragments and alternative ligand formats.…”