Affinity interactions of human immunoglobulin G with short peptides: role of ligand spacer on binding, kinetics, and mass transfer

Abstract

The interaction affinity between human IgG and a short peptide ligand (hexameric HWRGWV) was investigated by following the shifts in frequency and energy dissipation in a quartz crystal microbalance (QCM). HWRGWV was immobilized by means of poly(ethylene glycol) tethered on QCM sensors coated with silicon oxide, which enhanced the accessibility of the peptide to hIgG and also passivated the surface. Ellipsometry and ToF-SIMS were employed for surface characterization. The peptide ligand density was optimized to 0.88 chains nm(-2), which enabled the interaction of each hIgG molecule with at least one ligand. The maximum binding capacity was found to be 4.6 mg m(-2), corresponding to a monolayer of hIgG, similar to the values for chromatographic resins. Dissociation constants were lower than those obtained from resins, possibly due to overestimation of bound mass by QCM. Equilibrium thermodynamic and kinetic parameters were determined, shedding light on interfacial effects important for detection and bioseparation. Graphical Abstract The interaction affinity between human IgG and a short peptide ligand was investigated by using quartz crystal microgravimetry, ellipsometry and ToF-SIMS. Equilibrium thermodynamic and kinetics parameters were determined, shedding light on interfacial effects important for detection and bioseparation.

A sandwich immunoassay for brucellosis diagnosis based on immune magnetic beads and quantum dots

“…In addition, SPA can combine antibodies at room temperature. SPA has potential applications in disease diagnosis in place of the traditional secondary antibody [24,25]. In the absence of Brucella antibodies in the tested serum, the QDs-SPA probe cannot link to the IMB probe, and after separation with a magnet, there is no increase in the fluorescence intensity from the resuspended liquid.…”

Small-Sized Co-Polymers for Targeted Delivery of Multiple Imaging and Therapeutic Agents

“…In particular, these were antibodies against the TfR or insulin receptor. Dissociation constants of receptor-antibody complexes (K d ) and rate constants of their formation and dissociation (k on and k off, respectively) had extreme values, with K d = 0.1-5.0 nM, k on = (10 4 to 10 6 ) M −1 s −1 and k off = (10 −6 to 10 −3 ) s −1 [81][82][83][84][85][86], corresponding to residence times of hours and even days, which were unfavorable for drug delivery. In contrast, peptides with moderate receptor binding affinities of K d = 0.1-5.0 µM, k on = (10 5 to 10 8 ) M −1 s −1 , and k off = (10 −2 to 600) s −1 [33,38,42,44,46,47,[87][88][89][90] have residence times of 2 ms to 2 min, allowing a high degree of mass flow through the BBB.…”

Interactions between Metal Oxides and Biomolecules: from Fundamental Understanding to Applications

“…The biomolecules reported on so far include amino acids, small penta or hexa peptides, ,, longer peptides, human IgG, and hexameric peptide ligand (HWRGWV). In the study using HWRGWW, the short peptide ligand was immobilized on the surface of silica-coated QCM sensors using polyethylene glycol as a solvent with a surface density of ∼0.8 chains nm –2 reported to result in an increased surface accessibility and allowing a proper orientation of the peptide to IgG …”

“…QCM-D is an established technique for probing abiotic–biotic interaction processes such as MOs and biomolecules as has been demonstrated in various studies with TiO 2 , and SiO 2 . ,− , Limited stability of ZnO films in an aqueous environment has currently precluded its use in the study of ZnO biomolecule interactions. Experimental information obtained using QCM-D such as adsorbed/desorbed mass/thickness, rigidity, or softness of an adlayer, and possible determination of orientation of adsorbed biomolecules can be used to investigate the mechanism behind specific MO-biomolecule interactions.…”