Interaction between bovine serum albumin and Solutol® HS 15 micelles: A two-stage and concentration-dependent process

Physicochemical characterization, release profile, and antibacterial mechanisms of caffeic acid phenethyl ester loaded in lipid nanocapsules with lauric acid and glycerol monolaurate

Numerous studies have demonstrated the biological activities of caffeic acid phenethyl ester (CAPE), including antibacterial, antioxidant, and anti-inflammatory properties. However, the application of CAPE is limited by its low bioavailability and stability. In this work, we designed a CAPE loaded nanocapsule system by using polyoxyl-15-hydroxystearate, coconut oil and lecithin (LE)/lauric acid (LA)/glycerol monolaurate (GML) to improve the release rate of CAPE. The Blank-GML-lipid nanocapsules (BK-GML) and CAPE loaded BK-GML (CAPE-GML) were mainly assembled by hydrophobic forces and electrostatic forces, exhibited a typical spherical shape with a diameter size of less than 90 nm. The encapsulation and loading efficiencies of BK-GML and CAPE-GML reached 74.27 % and 9.61 %, respectively. Lipid nanocapsules (LNCs) also demonstrated a good sustained release of CAPE during in vitro stimulated digestion, indicating LNCs enable sustained CAPE release to the colon. Additionally, they showed a strong antibacterial activity against Escherichia coli and Staphylococcus aureus through the damage of the bacterial cytoderm. Also, BK-GML and CAPE-GML could inhibit the contamination and spread of pathogenic bacteria to be further applied in foods and pharmaceuticals industries.

In Situ Measurement of Nanoparticle-Blood Protein Adsorption and Its Heterogeneity with Single-Nanoparticle Resolution via Dual Fluorescence Quantification

The formation of a protein corona gives nanomedicines a distinct biological identity, profoundly influencing their fate in the body. Nonspecific nanoparticle-protein interactions are typically highly heterogeneous, which can lead to unique biological behaviors and in vivo fates for individual nanoparticles that remain underexplored. To address this, we have established an in situ approach that allows quantitative examination of nanoparticle-protein adsorption at the individual nanoparticle level. This method integrates dual fluorescence quantification techniques, wherein the nanoparticles are first individually analyzed via nanoflow cytometry to detect fluorescent signals from adsorbed proteins. The obtained fluorescence intensity is then translated into protein quantities through calibration with microplate reader quantification. Consequently, this approach enables analysis of interparticle heterogeneity of nano-protein interactions, as well as in situ monitoring of protein adsorption kinetics and nanoparticle aggregation status in blood serum, preconditioning for a comprehensive understanding of nano-bio interactions, and predicting in vivo fate of nanomedicines.

The Effect of Sulfobetaine Coating in Inhibiting the Interaction between Lyotropic Liquid Crystalline Nanogels and Proteins

The injective lyotropic liquid crystalline nanogels (LLCNs) were widely used in drug delivery systems. But when administered in vivo, LLCNs exposed to the biological environment interact with proteins. Recently, it has been shown that nanoparticles coated with zwitterions can inhibit their interaction with proteins. Thus, in this study, the interaction between proteins and LLCNs coated with the zwitterionic material sulfobetaine (GLLCNs@HDSB) was investigated using bovine serum albumin (BSA) as a model protein. Interestingly, it was found that GLLCNs@HDSB at higher concentrations (≥0.8 mg/mL) could block its interaction with BSA, but not at lower concentrations (<0.8 mg/mL), according to the results of ultraviolet, fluorescence, and circular dichroism spectra. In the ultraviolet spectra, the absorbance of GLLCNs@HDSB (0.8 mg/mL) was 1.9 times higher than that without the sulfobetaine coating (GLLCNs) after incubation with protein; the fluorescence quenching intensity of GLLCNs@HDSB was conversely larger than that of the GLLCNs; in circular dichroism spectra, the ellipticity value of GLLCNs@HDSB was significantly smaller than that of the GLLCNs, and the change in GLLCNs@HDSB was 10 times higher than that of the GLLCNs. Generally, nanoparticles coated with sulfobetaine can inhibit their interaction with proteins, but in this study, LLCNs showed a concentration-dependent inhibitory effect. It could be inferred that in contrast to the surface of nanoparticles covered with sulfobetaine in other cases, the sulfobetaine in this study interacted with the LLCNs and was partially inserted into the hydrophobic region of the LLCNs. In conclusion, this study suggests that coating-modified nanoparticles do not necessarily avoid interacting with proteins, and we should also study coating-modified nanoparticles interacting with proteins both in vitro and in vivo. In the future, finding a coating material to completely inhibit the interaction between LLCNs and proteins will generate a great impetus to promote the clinical transformation of LLCNs.