Adsorption of bovine serum albumin (BSA) by bare magnetite nanoparticles with surface oxidative impurities that prevent aggregation

Abstract

Bare, uncoated magnetite nanoparticles, synthesized using an electrochemical surfactant-free synthesis, have highly oxidized surfaces that prevent aggregation. These particles have demonstrated highly intriguing biological activity showing extremely potent antibiotic activity against both gram-positive and gram-negative bacteria with little toxicity to rats. This difference in activity could be ascribed to the nature of the protein corona. The kinetics and thermodynamics of the binding of bovine serum albumin (BSA), used as a model serum protein, to these magnetite nanoparticles were analyzed. There is no significant change in particle diameter by dynamic light scattering following adsorption, indicating corona formation does not induce aggregation. The maximum adsorption capacity of the particles was determined to be 300 mg of BSA per gram of magnetite. The particles are able to adsorb 90% of the BSA at protein concentrations as high as 500 mg/L. The adsorption is best described using a pseudo second order model and a Langmuir Type III isotherm model. Thermodynamic analysis showed that the process is entropically driven and is spontaneous at all tested temperatures and conditions. However, it appears to be a weak to moderate physical adsorption. This moderate binding affinity could indicate the differential biological activity of these particles towards bacteria and mammalian cells and further support the contention that these are potentially useful new tools for targeting antibiotic-resistant bacteria.

Selective ene‐reductase immobilization to magnetic nanoparticles through a novel affinity tag

“…[19,35,[40][41][42][43] The rise of the load after the plateau can be caused by multilayer adsorption. [9,36,44] For comparison, an ene-reductase immobilized on EziG glass particles exhibited an up to 100 times smaller load of 0.004 g g -1 . [45]…”

Oligoarginine Peptide Conjugated to BSA Improves Cell Penetration of Gold Nanorods and Nanoprisms for Biomedical Applications

“…It has been demonstrated by several spectroscopic techniques that BSA is spontaneously adsorbed in the surface of AuNPs via S-Au bonds between the free SH groups of BSA and the gold atoms in the AuNP surface [ 42 , 67 , 68 , 69 , 70 , 71 ]. Therefore, both AuNRs and AuNPrs were coated with BSA and the functionalized BSA-A565-r 8 by incubation, as summarized in Table 1 and Figure 2 and Figure 3 .…”

“…BSA shares 76% sequence identity with human serum albumin (HSA) [ 37 ] and is well tolerated by humans [ 38 ]. This protein has been extensively used for the development of nanomaterials for biomedical applications in drug delivery, therapy (photothermal or combined), diagnosis, and theranostics [ 39 , 40 , 41 , 42 , 43 , 44 , 45 ].…”

Synthesis, physical characterization, and antifungal and antibacterial activities of oleic acid capped nanomagnetite and cobalt-doped nanomagnetite

“…Cobalt-doping magnetite provides the materials with increased hardness, higher electrical resistivity and higher electrical permeability at higher frequencies. [20][21] Our previous work with nanomagnetite has focused on using them as antibiotics, [22][23][24][25][26] and there are multiple excellent recent reviews on the subject. [27][28] Nanomagnetite has been extensively studied by others for antibiotic applications as core-shell formulations, [29][30] as uncoated nanoparticles, 31-32 as nanoparticles either doped or combined with other metals, [33][34][35] or simply as drug delivery vehicles where the antibiotics adsorbed onto the surface.…”

“…36 We have previously investigated the antibiotic potential of uncoated magnetite prepared using an additive-free electrochemical approach. [23][24][25][26] The surface of these particles incorporated highly oxidized impurities that both inhibited aggregation and were responsible for the potent antibacterial activity. However, we wanted to explore the activity of a more traditional magnetite formulation and help determine whether the activity observed was due to the presence of Fe-O-O-H groups or due to the activity of the magnetite functionality.…”