[PMC free article] [PubMed] [Google Scholar] 35

[PMC free article] [PubMed] [Google Scholar] 35. the scFv fusion construct and by employing scFvs that are specific for targets with vastly different sizes. Using computational models we extracted multivalent kinetic rate constants for particle attachment and detachment from the adhesion data and correlated the results to molecular binding properties. Our results indicate that this factors that increase encounter probability, such as adhesion molecule valency and size, directly enhance the rate of nanoparticle attachment. Bond kinetics had no influence on scFv-mediated nanoparticle attachment within the kinetic range tested however, but did appear to effect antibody/antigen and avidin/biotin mediated adhesion. We attribute this obtaining to a combination of multivalent binding and differences in bond mechanical strength between recombinant scFvs and the other adhesion molecules. Nanoparticle detachment probability correlated directly with adhesion molecule valency and size, as well as the logarithm of the affinity for all those molecules tested. Based on this work, scFvs can serve as viable targeting receptors for nanoparticles, but improvements to their bond mechanical strength would likely be required to fully exploit their tunable kinetic properties and maximize the adhesion efficiency of nanoparticles that bear them. Keywords: nanoparticles, multivalent binding, molecular targeting, single-chain antibody (scFv), avidin-biotin, VCAM-1 INTRODUCTION A major goal of the field of drug delivery is to develop targeted therapeutic delivery systems that can reduce or eliminate the adverse side-effects associated with traditional systemic administration. Nanoparticles have emerged as important materials for this application because they can carry large drug cargos, can readily be altered with affinity molecules for targeted binding, and can make use of multivalency for improved binding properties.1 In previous work, we established fundamental principles to quantify the adhesion of multivalent nanoparticles under fluid flow, and elucidated fundamental scaling Afloqualone laws that related the adhesion rate constant and dissociation rate constant to molecular surface densities, flow rate, and nanoparticle size.2, 3 However, to date very little is known regarding the relationship between targeting molecule binding properties and nanoparticle adhesion. Here we provide insight into the influence of molecular binding properties by attaching a spectrum of different targeting molecules to nanoparticles and quantifying adhesion. A particular focus of this work is usually on recombinant antibody fragments (single-chain antibodies, scFvs), which have been widely used as nanocarrier targeting moieties Afloqualone both in vitro4C6 and in vivo.7C11 scFvs are particularly attractive for our purposes because their binding properties can readily be Afloqualone engineered using directed evolution.12 For example, the 4-4-20 anti-fluorescein scFv was evolved through multiple rounds of directed evolution to yield a library of mutants displaying greater than 10,000-fold differences in = and an internal property that set the sensitivity to pressure.16 Evans17 and later Dembo and coworkers18 suggested that detachment is driven by the logarithm of the affinity constant, a relationship that was later corroborated by Kuo and Lauffenburger experimentally19 and computationally using Adhesive Dynamics simulations.20 Our laboratory has also used Adhesive Dynamics simulations to elucidate the quantitative relationship between bond mechanical strength and the dynamics of cell adhesion, suggesting mechanical properties that lead to diverse phenomena such as rolling, firm, or weak adhesion.21 Thus it is expected that bond mechanical strength will vary as a weak function of the bond affinity, as well as LAMA3 antibody an intrinsic property (reactive compliance) of the bond that establishes the sensitivity to force. Finally, bond length defines the spatial constraints over which adhesion molecules can locate binding partners. Israelachvili and coworkers strongly established that adhesion can be enhanced when ligands are placed on long, flexible tethers.22 Molecular length has also been shown to directly affect encounter frequency and bond formation rate in micropipette-based binding assays.23 While we expect that bond kinetics, thermodynamics, mechanics, and length may all play significant functions in dictating nanocarrier adhesion dynamics under fluid flow, detailed experiments aimed at quantifying these associations have yet to be performed..

Intravenous immunoglobulin (IVIg) is usually a human polyspecific IgG (presented as monomeric or multimeric forms) and derives from the plasma of thousands healthy individuals (3,000-80,000)

We evaluated the efficacies of these immunizations by using transgenic parasites expressing either PfCSP or Pfs25 inside a murine magic size, which facilitates the optimization of vaccine immunogenicity (42)

﻿Intravenous immunoglobulin (IVIg) is usually a human polyspecific IgG (presented as monomeric or multimeric forms) and derives from the plasma of thousands healthy individuals (3,000-80,000)

﻿We evaluated the efficacies of these immunizations by using transgenic parasites expressing either PfCSP or Pfs25 inside a murine magic size, which facilitates the optimization of vaccine immunogenicity (42)

Intravenous immunoglobulin (IVIg) is usually a human polyspecific IgG (presented as monomeric or multimeric forms) and derives from the plasma of thousands healthy individuals (3,000-80,000)

We evaluated the efficacies of these immunizations by using transgenic parasites expressing either PfCSP or Pfs25 inside a murine magic size, which facilitates the optimization of vaccine immunogenicity (42)