Probing Nanoparticle−Protein Interaction by Capillary Electrophoresis

Abstract

Understanding nanoparticle-protein interaction could help in promoting applications of nanoparticles in the biomedical fields and reducing/preventing possible adverse effects to the biological systems caused by nanoparticles. Quantitative measurement of the biophysical parameters of nanoparticle-protein interaction will improve such understanding, which could be conveniently performed by capillary electrophoresis (CE) as demonstrated in the present study. Two interaction situations were identified. Stable nanoparticle-protein complexes were resolved from the free nanoparticles and the proteins by capillary zone electrophoresis (CZE). Transient complexes with fast association/dissociation rates showed distinct mobility change from the free nanoparticles in affinity capillary electrophoresis (ACE). Interactions of bovine serum albumin (BSA) with the Fe(3)O(4) nanoparticles (average diameters of 8 and 10 nm) and with the Au nanoparticles (average diameters of 5 and 10 nm) displayed slow and fast binding kinetics, respectively. Using the Hill equation, we could calculate the dissociation constants (K(D)) and cooperativity coefficients (n). Impacts on nanoparticle-protein interaction from the physicochemical properties of nanoparticles and the incubation buffer were evaluated on the basis of the K(D) and n values to interpret the interaction driving forces. Our study demonstrated the high simplicity and flexibility of CE in probing the interaction of proteins with diverse particles. The separation power of CE should also facilitate studies of the multicomponent interaction systems for investigating how adsorption onto nanoparticles could affect the protein-protein or protein-small molecule interactions.

Dissociation coefficients of protein adsorption to nanoparticles as quantitative metrics for description of the protein corona: A comparison of experimental techniques and methodological relevance

“…The charge change due to protein binding to NPs hence modifies their electrophoretic mobility, which in this way reflects the amount the amount of bound proteins protein. Hence the relative changes in the retention of the NP-protein conjugates as a function of the protein dose can be a parameter for protein binding to NPs and can be fitted with appropriate mathematical models, like the Hill model [59], in order to obtain K D and n as fit parameters. This method has several advantages.…”

Characterization of gold nanoparticles with different hydrophilic coatings via capillary electrophoresis and Taylor dispersion analysis. Part I: Determination of the zeta potential employing a modified analytic approximation

“…CE is a separation technique that permits to separate the NPs of interest from further constituents of the sample and to separate NPs according to differences in size and/or their surface charge density [12][13][14][15][16][17][18][19][20][21]. CE has been shown to enable to calculate conversion degrees [22] and to probe NP-protein interactions [23]. In addition, it allows to gain insight into the presence or absence of agglomerates [24,25], to detect fractions with different migration behaviors [26] (e.g.…”

Simultaneous detection of assembly and disassembly of multivalent HA tag and anti‐HA antibody in single in‐capillary assay

“…Using the Hill equation, we could compare the in-capillary assay and the out of-capillary assay and calculate K D and n values [28]. The plot of ɵ(QDs bound /QDs total ) with YPYDH 6 concentration fit to the Hill equation well (Fig.…”