Formation of β-Lactoglobulin Self-Assemblies via Liquid-Liquid Phase Separation for Applications beyond the Biological Functions

Life at the interface: Engineering bio-nanomaterials through interfacial molecular self-assembly

Interfacial self-assembly describes the directed organization of molecules and colloids at phase boundaries. Believed to be fundamental to the inception of primordial life, interfacial assembly is exploited by a myriad of eukaryotic and prokaryotic organisms to execute physiologic activities and maintain homeostasis. Inspired by these natural systems, chemists, engineers, and materials scientists have sought to harness the thermodynamic equilibria at phase boundaries to create multi-dimensional, highly ordered, and functional nanomaterials. Recent advances in our understanding of the biophysical principles guiding molecular assembly at gas-solid, gas-liquid, solid-liquid, and liquid-liquid interphases have enhanced the rational design of functional bio-nanomaterials, particularly in the fields of biosensing, bioimaging and biotherapy. Continued development of non-canonical building blocks, paired with deeper mechanistic insights into interphase self-assembly, holds promise to yield next generation interfacial bio-nanomaterials with unique, and perhaps yet unrealized, properties. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Emerging Technologies.

High-efficiency antibacterial calcium alginate/lysozyme/AgNPs composite sponge for wound healing

Infection poses a significant barrier to effective wound repair, leading to increased inflammatory responses that ultimately result in incomplete and prolonged wound healing. To address this challenge, numerous antibacterial ingredients have been incorporated into dressings to inhibit wound infection. Our previous work demonstrated that lysozyme/silver nanoparticles (LYZ/AgNPs) complexes, prepared using an eco-friendly one-step aqueous method, exhibited excellent antibacterial efficacy with favorable biosafety. To further explore its potential application in advancing wound healing, calcium alginate (CA) with good porosity, water absorption, and water retention capacities was formulated with LYZ/AgNPs to prepare composite sponge (CA/LYZ/AgNPs). As expected, in vivo experiments involving full-thickness skin wound and scald wound healing experiments demonstrated that CA-LYZ-AgNPs composite sponges with excellent biocompatibility exhibited remarkable antibacterial activity against gram-positive bacteria, gram-negative bacteria and fungi, and outperformed the wound healing process efficacy of other commercially available AgNPs-loaded wound dressings. In summary, this work introduces a CA/LYZ/AgNPs sponge featuring exceptional antibacterial efficacy and biocompatibility, thus holding promising potential in wound care applications.

High Reactivity of Supermolecular Nanoentities of a Vitamin B12 Derivative in Langmuir-Schaefer Films Toward Gaseous Toxins

Recently, we have described the first supermolecular nanoentities (SMEs) of a vitamin B12 derivative, viz., a monocyano form of heptabutyl cobyrinate ((CN-)BuCby), unique nanoparticles with strong noncovalent intermolecular interactions, and emerging optical and redox properties. In this work, the fast response of thin films based on the SMEs of the B12 derivative to gaseous toxins (viz., hydrogen cyanide, ammonia, sulfur dioxide, and hydrogen sulfide) particularly dangerous for humans was demonstrated. The reaction between SMEs of (CN-)BuCby in Langmuir-Schaefer (LS) films and HCN generates dicyano species and proceeds ca. 5-fold more rapidly than the process involving drop-coated films that contain (CN-)BuCby in molecular form. The highest sensitivity toward HCN was achieved by using thicker LS films. The reaction proceeds reversibly: upon exposure to air, the dicyano complex undergoes partial decyanation. The decyanated complex retains reactivity toward HCN for at least four subsequent cycles. The processes involving SMEs of (CN-)BuCby and NH3, SO2, and H2S are irreversible, and the sensitivity of the films toward these gases is lower in comparison with HCN. Presented data provides mechanistic information on the reactions involving solid vitamin B12 derivatives and gaseous toxins. In the case of NH3, deprotonation of the coordinated Co(III)-ion water molecule occurs, and the generated hydroxocyano species exhibit high air stability. After binding of SO2, a mixture of sulfito and dicyano species is produced, and the regenerated film contains aquacyano and diaqua or aquahydroxo species, which possess high reactivity toward gaseous toxins. Reaction with H2S produces a mixture of the Co(III)-dicyano form and Co(II)-species containing sulfide oxidation products, which are resistant to aerobic oxidation. Our findings can be used for the development of naked-eye, electronic optic, and chemiresistive sensors toward gaseous toxins with improved reactivity for prompt cyanide detection in air, blood, and plant samples and for analysis of exhaled gases for the diagnosis of diseases.

Biogenic engineered nanomaterials for enhancing bioavailability via developing nano-iron-fortified smart foods: advances, insight, and prospects of nanobionics in fortification of food

Iron deficiency is a significant cause of iron deficiency anemia (IDA). Treatment of IDA is challenging due to several challenges, including low target bioavailability, low palatability, poor pharmacokinetics, and extended therapeutic regimes. Nanotechnology holds the promise of revolutionizing the management and treatment of IDA. Smart biogenic engineered nanomaterials (BENMs) such as lipids, protein, carbohydrates, and complex nanomaterials have been the subject of extensive research and opened new avenues for people and the planet due to their enhanced physicochemical, rheological, optoelectronic, thermomechanical, biological, magnetic, and nutritional properties. Additionally, they show eco-sustainability, low biotoxicity, active targeting, enhanced permeation and retention, and stimuli-responsive characteristics. We examine the opportunities offered by emerging smart BENMs for the treatment of iron deficiency anemia by utilizing iron-fortified smart foods. We review the progress made so far and other future directions to maximize the impact of smart nanofortification on the global population. The toxicity effects are also discussed with commercialization challenges.

Supermolecular Nanoentities of Vitamin B12 Derivative as a Link in the Evolution of the Parent Molecules During Self-Assembly at the Air-Water Interface

Nanoarchitectures with promising properties have now been formed from many important biomolecules. However, the preparation of nanoparticles of vitamin B₁₂ and its derivatives remains an ongoing research challenge. This paper describes the formation of supermolecular nanoentities (SMEs) of vitamin B₁₂ derivatives, unique nanoparticles with strong noncovalent intermolecular interactions, emerging properties, and activity. These were created by a nanoarchitectonic approach using directed assembly of layers at the air-water interface as a link in the chain of evolution of the parent molecules under specially created conditions. Such layers can be represented as a nanocosm, where, at a critical density, the assemblies act as nanoreactors in which the transformation of the original material occurs. The discovered SMEs not only replicate the functioning of vitamin B₁₂ assemblies with proteins in living organisms and act as vitamin B₁₂-depended enzymes but also demonstrate important advantages over vitamin B₁₂. They are more efficient in oxygen reduction/evolution reactions and in transformation into other forms. These SMEs, in performing advanced tasks, are an alternative to widely used materials based on noble metals for catalysis, medicine, and environment protection. Our findings open new perspectives both for the fabrication of novel SMEs of biomolecules and for a better understanding of the evolution of biomolecules in nature.

Molecular insights into alginate β-lactoglobulin A multivalencies-The foundation for their amorphous aggregates and coacervation

For improved control of biomaterial property design, a better understanding of complex coacervation involving anionic polysaccharides and proteins is needed. Here, we address the initial steps in condensate formation of β-lactoglobulin A (β-LgA) with nine defined alginate oligosaccharides (AOSs) and describe their multivalent interactions in structural detail. Binding of AOSs containing four, five, or six uronic acid residues (UARs), either all mannuronate (M), all guluronate (G), or alternating M and G embodying the block structural components of alginates, was characterized by isothermal titration calorimetry, nuclear magnetic resonance spectroscopy (NMR), and molecular docking. β-LgA was highly multivalent exhibiting binding stoichiometries decreasing from five to two AOSs with increasing degree of polymerization (DP) and similar affinities in the mid micromolar range. The different AOS binding sites on β-LgA were identified by NMR chemical shift perturbation analyses and showed diverse compositions of charged, polar and hydrophobic residues. Distinct sites for the shorter AOSs merged to accommodate longer AOSs. The AOSs bound dynamically to β-LgA, as concluded from saturation transfer difference and ¹ H-ligand-targeted NMR analyses. Molecular docking using Glide within the Schrödinger suite 2016-1 revealed the orientation of AOSs to only vary slightly at the preferred β-LgA binding site resulting in similar XP glide scores. The multivalency coupled with highly dynamic AOS binding with lack of confined conformations in the β-LgA complexes may help explain the first steps toward disordered β-LgA alginate coacervate structures.

Amyloid Protein Cross-Seeding Provides a New Perspective on Multiple Diseases In Vivo

Amyloid protein cross-seeding is a peculiar phenomenon of cross-spreading among different diseases. Unlike traditional infectious ones, diseases caused by amyloid protein cross-seeding are spread by misfolded proteins instead of pathogens. As a consequence of the interactions among misfolded heterologous proteins or polypeptides, amyloid protein cross-seeding is considered to be the crucial cause of overlapping pathological transmission between various protein misfolding disorders (PMDs) in multiple tissues and cells. Here, we briefly review the phenomenon of cross-seeding among amyloid proteins. As an interesting example worth mentioning, the potential links between the novel coronavirus pneumonia (COVID-19) and some neurodegenerative diseases might be related to the amyloid protein cross-seeding, thus may cause an undesirable trend in the incidence of PMDs around the world. We then summarize the theoretical models as well as the experimental techniques for studying amyloid protein cross-seeding. Finally, we conclude with an outlook on the challenges and opportunities for basic research in this field. Cross-seeding of amyloid opens up a new perspective in our understanding of the process of amyloidogenesis, which is crucial for the development of new treatments for diseases. It is therefore valuable but still challenging to explore the cross-seeding system of amyloid protein as well as to reveal the structural basis and the intricate processes.

Antibacterial activity of lysozyme-loaded cream against MRSA and promotion of scalded wound healing

Staphylococcus aureus (S. aureus) infection, especially its drug-resistant bacterial infection, is a great challenge often faced by clinicians and patients, and it is also one of the most important threats to public health. Finding a safe and effective antibacterial agent is of great significance for the prevention and treatment of S. aureus infection. Lysozyme is known to have antibacterial effects against Gram-positive bacteria including S. aureus. Here, high-quality lysozyme with a purity of more than 99% and an activity of more than 60, 000 U/mg was prepared from egg white, which showed excellent antibacterial activity against three strains of S. aureus, especially against MRSA. Furthermore, an antibacterial cream loaded with lysozyme was prepared and tested in scald wound healing. The lysozyme-loaded cream exhibited the effect of preventing wound infection and promoting wound healing on scalds, and no toxicity was found in animal organs. Overall, lysozyme showed great application potential in the prevention and treatment of infections caused by S. aureus and scalded wound healing. The most remarkable discovery in this work is the unexpectedly powerful inhibitory effect of lysozyme on the drug-resistant bacterial, especially MRSA, which is usually very difficult to deal with using normal antibacterial drugs.

Compartmentalized Aqueous-in-Aqueous Droplets for Flow Biocatalysis

Compartmentalized bioreactions are vital for living cells to regulate biological events since they facilitate isolated yet orchestrated reactions and releases of biological molecules. Engineering bioreactions in compartmentalized droplet bioreactors not only promotes understanding of biological cells but also enhances control in synthetic biology systems. A typical droplet bioreactor is enclosed by impermeable water-in-oil interfaces, which inhibit the reaction rate with the accumulation of aqueous products. This work constructs aqueous two-phase system (ATPS) droplet bioreactors featuring selectively permeable interfaces, which are capable of sequestering reagents in aqueous droplets while constantly releasing products into the aqueous surroundings. Benefiting from this selective permeability, the proposed droplet bioreactor achieves a conversion rate up to 63.2% compared to the 17.9% from the impermeable aqueous-in-oil droplet reactor via coupled reaction-separation. More importantly, it is revealed that uniform aqueous-in-aqueous droplet clusters by microfluidics exhibit an up to 6-fold reaction rate enhancement compared to non-microfluidic ATPS reactors, indicating a unique flow interface effect in droplet clusters. This work offers a new route to allow enzymatic reactions to benefit from efficient flow chemistry via optimized aqueous-aqueous interfaces.

Investigating Chaperone like Activity of Green Silver Nanoparticles: Possible Implications in Drug Development

Protein aggregation and amyloidogenesis have been associated with several neurodegenerative disorders like Alzheimer’s, Parkinson’s etc. Unfortunately, there are still no proper drugs and no effective treatment available. Due to the unique properties of noble metallic nanoparticles, they have been used in diverse fields of biomedicine like drug designing, drug delivery, tumour targeting, bio-sensing, tissue engineering etc. Small-sized silver nanoparticles have been reported to have anti-biotic, anti-cancer and anti-viral activities apart from their cytotoxic effects. The current study was carried out in a carefully designed in-vitro to observe the anti-amyloidogenic and inhibitory effects of biologically synthesized green silver nanoparticles (B-AgNPs) on human serum albumin (HSA) aggregation taken as a model protein. We have used different biophysical assays like thioflavin T (ThT), 8-Anilino-1-naphthalene-sulphonic acid (ANS), Far-UV CD etc. to analyze protein aggregation and aggregation inhibition in vitro. It has been observed that the synthesized fluorescent B-AgNPs showed inhibitory effects on protein aggregation in a concentration-dependent manner reaching a plateau, after which the effect of aggregation inhibition was significantly declined. We also observed meaningful chaperone-like aggregation-inhibition activities of as-synthesized florescent B-AgNPs in astrocytes.