Size-dependent binding of pristine fullerene (nC 60 ) nanoparticles to bovine/human serum albumin

Anti-Inflammatory and Antioxidant Effects of Liposoluble C60 at the Cellular, Molecular, and Whole-Animal Levels

Introduction

Liposoluble carbon-60 (C60) has potential applications in many fields, including cosmetics, medical devices, and medicine, but its specific mechanism of action remains unclear. This study explored whether liposoluble C60 could be delivered to human organs, tissues, and cells through blood, extracellular fluid, and cell culture fluid and whether it exerts anti-inflammatory and antioxidant effects at the molecular, cellular, and whole-animal levels.

Methods

At the cellular level, we mixed C60 dissolved in grape seed oil with cell culture medium containing 10% serum and investigated its effects on tumor necrosis factor-α (TNF-α) release, migration, phagocytosis, respiratory burst, and apoptosis in freshly isolated human neutrophils. At the molecular level, we mixed a trace amount of C60 dissolved in grape seed oil with aqueous and ethanolic solutions and studied its antioxidant effect. At the animal level, we investigated the inhibitory effect of C60 on the serum inflammatory marker C-reactive protein (CRP) in beagle dogs after oral administration of C60 dissolved in grape seed oil.

Results

The results showed that the trace amount of C60 dissolved in grape seed oil significantly inhibited TNF-α release, cell migration, phagocytosis, and respiratory burst in freshly isolated human neutrophils. In addition, the trace amount of C60 dissolved in grape seed oil had a significant scavenging effect on superoxide free radicals and 1,1-diphenyl-2-trinitrophenylhydrazine free radicals. Oral administration of C60 dissolved in grape seed oil markedly reduced the level of the serum inflammatory marker CRP in beagle dogs.

Conclusion

In summary, a trace amount of hydrophobic C60 in hydrophilic media effectively produced anti-inflammatory and antioxidant effects in cells and animals. C60 dissolved in grape seed oil is a novel anti-inflammatory and antioxidant drug candidate.

Multispectroscopic studies on the molecular interactions between bovine gamma-globulin and borohydride-capped silver nanoparticles

Interactions between bovine gamma-globulin (BGG) and borohydride-capped silver nanoparticles (BAgNPs) were studied using dynamic light scattering and spectroscopic techniques like UV-Vis, fluorescence and circular dichroism. The results were compared with earlier reported^[1] interactions between γ-globulin and citrate-coated AgNPs (CAgNPs). BAgNPs were synthesized and characterized. Irrespective of the coating on AgNPs, nanoparticles had formed ground state complexes with the protein. CAgNPs as well as BAgNPS had caused static quenching of tryptophan (Trp) fluorescence of the protein. The change in the capping agent from citrate to borohydride weakened the binding of nanoparticles with the protein. But the same change in capping agent had increased the- fluorescence quenching efficiency of AgNPs. Hydrogen bonding and van der Waals interactions were involved in BGG-BAgNPs complex similar to the CAgNPs complex with γ-globulin. Polarity of the Trp microenvironment in BGG was not altered by BAgNPs contrary to CAgNPs as supported by synchronous and three-dimensional fluorescence. Resonance light scattering experiment also suggested nano-bio conjugation. Far-UV and near-UV CD spectra respectively pointed towards changes in the secondary and tertiary structure of BGG by BAgNPs, which was not observed in case of CAgNPs.

The interfacial interactions of nanomaterials with human serum albumin

The fates of nanomaterials (NMs) in vivo are greatly dependent on their interactions with human serum proteins. However, the interfacial molecular details of NMs-serum proteins are still difficult to be probed. Herein, the molecular interaction details of human serum albumin (HSA) with Au and SiO₂ nanoparticles have been systematically interrogated and compared by using lysine reactivity profiling mass spectrometry (LRP-MS). We demonstrated the biocompatibility of Au is better than SiO₂ nanoparticles and the NMs surface charge state played a more important role than particle size in the combination of NMs-HSA at least in the range of 15-40 nm. Our results will contribute to the fundamental mechanism understanding of NMs-serum protein interactions as well as the NMs rational design.

Investigating the Size-Dependent Binding of Pristine nC60 to Bovine Serum Albumin by Multi-Spectroscopic Techniques

The morphology of nanomaterials may affect their interaction with biomacromolecules such as proteins. Previous work has studied the size-dependent binding of pristine nC₆₀ to bovine/human serum albumin using the fluorometric method and found that the fluorescence inner filter effect might affect this interaction. However, if it is necessary to accurately calculate and obtain binding information, the fluorescence inner filter effect should not be ignored. This work aimed to further investigate the effect of the fluorescence inner filter on the interaction between pristine nC₆₀ with different particle sizes (140–160, 120–140, 90–110, 50–70, and 30–50 nm) and bovine serum albumin for a more accurate comprehension of the binding of pristine nC₆₀ to bovine serum albumin. The nC₆₀ nanoparticles with different size distributions used in the experiments were obtained by the solvent displacement and centrifugation method. UV-Vis spectroscopy and fluorescence spectroscopy were used to study the binding of nC₆₀ with different size distributions to bovine serum albumin (BSA) before and after eliminating the fluorescence inner filter effect. The results showed that the fluorescence inner filter effect had an influence on the interaction between nC₆₀ and proteins to some extent, and still did not change the rule of the size-dependent binding of nC₆₀ nanoparticles to BSA. Further studies on the binding parameters (binding constants and the number of binding sites) between them were performed, and the effect of the binding on BSA structures and conformation were also speculated.