Magnetic Nanoclusters Coated with Albumin, Casein, and Gelatin: Size Tuning, Relaxivity, Stability, Protein Corona, and Application in Nuclear Magnetic Resonance Immunoassay

Abstract

The surface functionalization of magnetic nanoparticles improves their physicochemical properties and applicability in biomedicine. Natural polymers, including proteins, are prospective coatings capable of increasing the stability, biocompatibility, and transverse relaxivity (r2) of magnetic nanoparticles. In this work, we functionalized the nanoclusters of carbon-coated iron nanoparticles with four proteins: bovine serum albumin, casein, and gelatins A and B, and we conducted a comprehensive comparative study of their properties essential to applications in biosensing. First, we examined the influence of environmental parameters on the size of prepared nanoclusters and synthesized protein-coated nanoclusters with a tunable size. Second, we showed that protein coating does not significantly influence the r2 relaxivity of clustered nanoparticles; however, the uniform distribution of individual nanoparticles inside the protein coating facilitates increased relaxivity. Third, we demonstrated the applicability of the obtained nanoclusters in biosensing by the development of a nuclear-magnetic-resonance-based immunoassay for the quantification of antibodies against tetanus toxoid. Fourth, the protein coronas of nanoclusters were studied using SDS-PAGE and Bradford protein assay. Finally, we compared the colloidal stability at various pH values and ionic strengths and in relevant complex media (i.e., blood serum, plasma, milk, juice, beer, and red wine), as well as the heat stability, resistance to proteolytic digestion, and shelf-life of protein-coated nanoclusters.

Effect of Iron-Oxide Nanoparticles Impregnated Bacterial Cellulose on Overall Properties of Alginate/Casein Hydrogels: Potential Injectable Biomaterial for Wound Healing Applications

“…Water soluble casein was prepared as per the procedure mentioned by Khramtsov et al [ 36 ] by adding casein powder to 1M NaOH to prepare 5% ( w/w ) suspension. The mixture was stirred overnight at ~100 rpm in a beaker to obtain a transparent solution.…”

Unveiling the Hidden Therapeutic Potential of Carnosine, a Molecule with a Multimodal Mechanism of Action: A Position Paper

“…By employing a rodent model of diet-induced obesity and metabolic syndrome, the authors demonstrated the ability of carnosinol to dose-dependently attenuate 4-hydroxynonenal adduct formation in liver and skeletal muscle, while simultaneously mitigating inflammation, dyslipidemia, insulin resistance, and steatohepatitis. As described by Grasso et al [ 136 ], alternative approaches to increase carnosine delivery and its bioavailability include the use of carnosine derivatives [ 137 , 138 , 139 ]; vesicular systems (nanoliposomes, niosomes, and polymerosomes) [ 140 , 141 , 142 , 143 ]; and nanoparticulate systems [ 144 , 145 , 146 , 147 ]. The currently “under-used” intranasal administration route might also represent an innovative approach, since it can purportedly bypass the BBB and first-pass metabolism [ 148 , 149 ]; the vasodilatory activity of carnosine [ 150 ] also makes this endogenous dipeptide an attractive candidate for this kind of delivery.…”

Serum Albumin for Magnetic Nanoparticles Coating

“…In comparison, tannic acid-coated MNPs already formed aggregates at 0.05 M and higher sodium chloride concentration [107]. The albumin-coated nanoparticles size did not alter for a long time in various pH and bioreagents temperature storage range and under 37 • C [26,109,111]. There were no significant changes in blood serum/plasma [26].…”

“…A modern approach is using biomolecules coating for improved biocompatibility [3,12]. Albumin adsorption prevents nucleation and the aggregation of MNPs, increases colloidal stability, and is optimal for the in vivo use of nanoparticles [26,[107][108][109][110][111][112][113][114][115][116]. For example, BSA-coated MNP remained excellent colloidal stability at 0.15 M sodium chloride concentration for more than one week.…”

“…The wrong coating leads to instability in the bloodstream and acute or delayed toxicity due to the highly reactive oxygen species (ROS) formation in cell lines and animal models [2,11,[19][20][21][22][23][24]. Protein coating usually possesses biocompatibility, biodegradability, less immunogenicity, and lower cytotoxicity of MNPs [25][26][27][28]. Recently, biotechnological applications of human serum albumin (HSA), including bioinspired materials and nanoparticles coating, were reported [29][30][31][32].…”