Revisiting the conformational state of albumin conjugated to gold nanoclusters: A self-assembly pathway to giant superstructures unraveled

Ultrasound-enhanced extraction unlocks superior functional properties and bioactive profles in Fucus vesiculosus proteins: A comprehensive characterization study

This study examined protein extraction from Fucus vesiculosus using both conventional and ultrasound-assisted extraction (UAE) methods, highlighting this seaweed's potential as a sustainable protein source. Both methods achieved optimal protein yields at 6 % alkali concentration, with UAE (43.98 % ± 0.49 %) producing a significantly higher yield compared to conventional extraction (39.29 % ± 1.66 %). UAE produced higher quality techno-functional properties proteins, as evidenced by several key findings. SDS-PAGE analysis showed protein distribution from 10 to 150 kDa, with conventional extraction yielding stronger bands than UAE across major molecular weight regions. Amino acid analysis showed a well-balanced profile with high concentrations of glutamic and aspartic acids and all essential amino acids. UAE significantly enhanced protein functionality by improving solubility across a broader pH range (9.41 % at pH 4 compared to 0.86 % for conventional extraction) and producing smaller, more stable particles (173.61-259.01 nm). Structural analyses using FTIR, fluorescence, and circular dichroism revealed that UAE induced partial protein unfolding and increased β-sheet content, which contributed to improved solubility, interfacial properties, and ultimately enhanced emulsifying and foaming properties. It also yielded higher levels of bioactive compounds, including phenolics (69.75 mg PGE/g) and antioxidants, with enhanced radical scavenging activities. While mineral content was higher in UAE samples, elevated arsenic levels require further investigation. Confocal laser scanning microscopy confirmed UAE's superior extraction efficiency through more uniform distribution of smaller protein particles. These findings demonstrate that UAE offers significant advantages over conventional methods for developing seaweed-based products with enhanced applications in food and pharmaceutical industries.

Preparation of bovine serum albumin nanospheres via desolvation: a study of synthesis, characterization, and aging

Serum albumin has myriad uses in biotechnology, but its value as a nanocarrier or nanoplatform for therapeutics is becoming increasingly important, notably with albumin-bound chemotherapeutics. Another emerging field is the fabrication of biopolymeric nanoparticles using albumin as a building block to achieve highly-tunable nonimmunogenic capsules or scaffolds that may be cheaply and reliably produced. The aim of this study was to characterize and optimize the desolvation process used for fabrication of albumin nanoparticles under ambient conditions, studying both glutaraldehyde (GT) and glucose (GLU) as crosslinking agents and the effect of various synthesis conditions including pH, electrolyte concentration, and rate of desolvation on particle size and stability. Particle size, polydispersity index, and zeta potential were investigated, morphology was examined using scanning electron microscopy (SEM), and long-term stability and degradation modes were studied using dynamic light scattering (DLS) and transmission electron microscopy (TEM). It was determined that the optimized synthesis procedure for synthesis of Bovine Serum Albumin (BSA) nanoparticles at the investigated scale under ambient conditions was addition of ethanol at a rate of 0.625 mL min-1via infusion against the vial wall and a pH of 9 with the addition of no other electrolytes. Optimized BSA nanoparticles were synthesized at a size of 86 ± 3.7 nm (σ = 1.85) using glutaraldehyde as a crosslinker and a size of 92 ± 1.9 nm (σ = 0.95) using glucose as a crosslinker with polydispersity indices of 0.08 and 0.05, respectively. Nanoparticles synthesized via the optimized procedure, using both crosslinkers, were found to maintain colloidal stability significantly longer than cases previously reported in the literature, with insignificant changes in hydrodynamic size many months after synthesis.

Effect of Gold Nanoparticles on the Conformation of Bovine Serum Albumin: Insights from CD Spectroscopic Analysis and Molecular Dynamics Simulations

With the development of nanotechnology, there is growing interest in using nanoparticles (NPs) for biomedical applications, such as diagnostics, drug delivery, imaging, and nanomedicine. The protein's structural stability plays a pivotal role in its functionality, and any alteration in this structure can have significant implications, including disease progression. Herein, we performed a combined experimental and computational study of the effect of gold NPs with a diameter of 5 nm (5 nm Au-NPs) on the structural stability of bovine serum albumin (BSA) protein in the absence and presence of NaCl salt. Circular dichroism spectroscopy showed a loss in the secondary structure of BSA due to the synergistic effect of Au-NPs and NaCl, and Thioflavin T fluorescence assays showed suppressed β-sheet formation in the presence of Au-NPs in PBS, emphasizing the intricate interplay between NPs and physiological conditions. Additionally, molecular dynamics (MD) simulations revealed that 5 nm Au-NP induced changes in the secondary structure of the BSA monomer in the presence of NaCl, highlighting the initial binding mechanism between BSA and Au-NP. Furthermore, MD simulations explored the effect of smaller Au-NP (3 nm) and nanocluster (Au-NC with the size of 1 nm) on the binding sites of the BSA monomer. Although the formation of stable BSA-Au conjugates was revealed in the presence of NPs of different sizes, no specific protein binding sites were observed. Moreover, due to its small size, 1 nm Au-NC decreased helical content and hydrogen bonds in the BSA monomer, promoting protein unfolding more significantly. In summary, this combined experimental and computational study provides comprehensive insights into the interactions among Au nanosized substances, BSA, and physiological conditions that are essential for developing tailored nanomaterials with enhanced biocompatibility and efficacy.

Antimicrobial Activity of Milk Whey in Different Mammals

Antimicrobial activity of milk whey in different mammals against Candida albicans yeast cells was studied by a spectrophotometric method. The activity increased in the order goat→horse→camel→cow→human→mouse. The level of whey activity in mice was higher by 3 and 10 times than in humans and goats, respectively. Similar changes were noted for activity of the whey fraction <100 kDa containing a complex of antimicrobial polypeptides, and there was a direct correlation between these two parameters (r=0.881; p<0.05). The total activity of whey had a high degree of correlation with the content of serum albumin (r=0.992); in mice, the level of serum albumin in the milk whey was close to that in blood serum. Interspecific differences between the activity of whey in mammals may be associated with qualitative and quantitative variability of the antimicrobial polypeptide composition, as well as their synergistic or antagonistic interaction with each other.

Enhanced surface nanoanalytics of transient biomolecular processes

Fundamental knowledge of the physical and chemical properties of biomolecules is key to understanding molecular processes in health and disease. Bulk and single-molecule analytical methods provide rich information about biomolecules but often require high concentrations and sample preparation away from physiologically relevant conditions. Here, we present the development and application of a lab-on-a-chip spray approach that combines rapid sample preparation, mixing, and deposition to integrate with a range of nanoanalytical methods in chemistry and biology, providing enhanced spectroscopic sensitivity and single-molecule spatial resolution. We demonstrate that this method enables multidimensional study of heterogeneous biomolecular systems over multiple length scales by nanoscopy and vibrational spectroscopy. We then illustrate the capabilities of this platform by capturing and analyzing the structural conformations of transient oligomeric species formed at the early stages of the self-assembly of α-synuclein, which are associated with the onset of Parkinson's disease.

Analytical separation techniques: toward achieving atomic precision in nanomaterials science

The size- and shape-dependence of the properties are the most characteristic features of nanoscale matter. In many types of nanomaterials, there is a size regime wherein every atom counts. In order to fully realize the idea of 'maneuvering things atom by atom' envisioned by Richard Feynman, synthesis and separation of nanoscale matter with atomic precision are essential. It is therefore not surprising that analytical separation techniques have contributed tremendously toward understanding the size- as well as shape-dependent properties of nanomaterials. Fascinating properties of nanomaterials would not have been explored without the use of these techniques. Here we discuss the pivotal role of analytical separation techniques in the progress of nanomaterials science. We begin with a brief overview of some of the key analytical separation techniques that are of tremendous importance in nanomaterials research. Then we describe how each of these techniques has contributed to the advancements in nanomaterials science taking some of the nanosystems as examples. We discuss the limitations and challenges of these techniques and future perspectives.

Tailoring the NIR-II Photoluminescence of Single Thiolated Au25 Nanoclusters by Selective Binding to Proteins

Atomically precise gold nanoclusters are a fascinating class of nanomaterials that exhibit molecule-like properties and have outstanding photoluminescence (PL). Their ultrasmall size, molecular chemistry, and biocompatibility make them extremely appealing for selective biomolecule labeling in investigations of biological mechanisms at the cellular and anatomical levels. In this work, we report a simple route to incorporate a preformed Au₂₅ nanocluster into a model bovine serum albumin (BSA) protein. A new approach combining small-angle X-ray scattering and molecular modeling provides a clear localization of a single Au₂₅ within the protein to a cysteine residue on the gold nanocluster surface. Attaching Au₂₅ to BSA strikingly modifies the PL properties with enhancement and a redshift in the second near-infrared (NIR-II) window. This study paves the way to conrol the design of selective sensitive probes in biomolecules through a ligand-based strategy to enable the optical detection of biomolecules in a cellular environment by live imaging.

Capping 1,3-propanedithiol to boost the antibacterial activity of protein-templated copper nanoclusters

We have prepared copper nanoclusters (Cu NCs) in the presence of bovine serum albumin (BSA) and 1,3-propanedithiol (PDT). The PDT/BSA-Cu NCs possess great activities against different types of bacteria, including non-multidrug-resistant bacteria (Escherichia coli, Salmonella Enteritidis, Pseudomonas aeruginosa, and Staphylococcus aureus) and multidrug-resistant bacteria (methicillin-resistant S. aureus). Their minimal inhibitory concentration (MIC) values are at least 242-fold and 10-fold lower than that of the free PDT and BSA-Cu NCs, respectively. The PDT/BSA-Cu NCs are strongly bound to the bacterial membrane, in which they induce the generation of ascorbyl (Asc) and perhydroxyl (HOO) radicals that result in disruption of their membrane integrity. At a concentration of 100-fold higher than their MIC for Escherichia coli, the PDT/BSA-Cu NCs exhibit negligible cytotoxicity towards the tested mammalian cells and show insignificant hemolysis. We have further demonstrated that low-cost PDT/BSA-Cu NCs-coated carbon fiber fabrics (CFFs) are effective against antibacterial growth, showing their great potential for antifouling applications.