Synergistic Coassembly of Folic Acid-Based Supramolecular Polymer with a Covalent Polymer Toward Fabricating Functional Antibacterial Biomaterials.

Supramolecular biomaterials can recapitulate the structural and functional facets of the native extracellular matrix and react to biochemical cues, leveraging the unique attributes of noncovalent interactions, including reversibility and tunability. However, the low mechanical properties of supramolecular biomaterials can restrict their utilization in specific applications. Combining the advantages of supramolecular polymers with covalent polymers can lead to the fabrication of tailor-made biomaterials with enhanced mechanical properties/degradability. Herein, we demonstrate a synergistic coassembled self-healing gel as a multifunctional supramolecular material. As the supramolecular polymer component, we chose folic acid (vitamin B9), an important biomolecule that forms a gel comprising one-dimensional (1D) supramolecular polymers. Integrating polyvinyl alcohol (PVA) into this supramolecular gel alters its ultrastructure and augments its mechanical properties. A drastic improvement of complex modulus (G*) (∼3674 times) was observed in the folic acid-PVA gel with 15% w/v PVA (33215 Pa) compared with the folic acid gel (9.04 Pa). The coassembled hydrogels possessed self-healing and injectable/thixotropic attributes and could be printed into specific three-dimensional (3D) shapes. Synergistically, the supramolecular polymers of folic acid also improve the toughness, durability, and ductility of the PVA films. A nanocomposite of the gels with silver nanoparticles exhibited excellent catalytic efficiency and antibacterial activity. The folic acid-PVA coassembled gels and films also possessed high cytocompatibility, substantiated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and live-dead assays. Taken together, the antibacterial and cell-adhesive attributes suggest potential applications of these coassembled biomaterials for tissue engineering and wound healing.

A repertoire of nanoengineered short peptide-based hydrogels and their applications in biotechnology.

Peptide nanotechnology has currently bridged the gap between materials and biological worlds. Bioinspired self-assembly of short-peptide building blocks helps take the leap from molecules to materials by taking inspiration from nature. Owing to their intrinsic biocompatibility, high water content, and extracellular matrix mimicking fibrous morphology, hydrogels engineered from the self-assembly of short peptides exemplify the actualization of peptide nanotechnology into biomedical products. However, the weak mechanical property of these hydrogels jeopardizes their practical applications. Moreover, their functional diversity is limited since they comprise only one building block. Nanoengineering the networks of these hydrogels by incorporating small molecules, polymers, and inorganic/carbon nanomaterials can augment the mechanical properties while retaining their dynamic supramolecular nature. These additives interact with the peptide building blocks supramolecularly and may enhance the branching of the networks via coassembly or crystallographic mismatch. This phenomenon expands the functional diversity of these hydrogels by synergistically combining the attributes of the individual building blocks. This review highlights such nanoengineered peptide hydrogels and their applications in biotechnology. We have included exemplary works on supramolecular modification of the peptide hydrogel networks by integrating other small molecules, synthetic/biopolymers, conductive polymers, and inorganic/carbon nanomaterials and shed light on their various utilities focusing on biotechnology. We finally envision some future prospects in this highly active field of research.

Neoroseomonas marina sp. nov., Isolated from a Beach Sand.

A pink-pigmented bacterium (strain JC162T = KCTC 32190T) was isolated from a beach sand sample. Cells were Gram-stain-negative, coccoid, non-motile, and strictly aerobic. EzBioCloud BLAST search of 16S rRNA gene sequence showed that strain KCTC 32190T had the highest sequence identity to the members of the genus Neoroseomonas and was closely related to N. oryzicola YC6724T (99.8%), N. sediminicola FW-3T (98.5%), N. soli 5N26T (98.2%), and other members of the genus Neoroseomonas (< 97.9%) in the family Acetobacteriaceae within the class of Alphaproteobacteria. Chemo-organoheterotrophy was the only growth mode and growth was possible on a wide range of organic substrates. Strain KCTC 32190T was positive for catalase and oxidase. Fatty acid composition of strain KCTC 32190T includes (in decreasing %) C18:1ω7c, cyclo-C19:0ω8c, C18:02-OH, C16:0, C18:03-OH, C16:1ω7c/C16:1ω6c, C16:02-OH and C16:1ω5c. Polar lipids comprised of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, an unidentified amino lipid, and three unidentified lipids. The genomic DNA G+C content of the strain KCTC 32190T was 70.9 mol%. Strain KCTC 32190T has a low ANI value of < 92.7% and genome reassociation (based on digital DNA-DNA hybridization) value of < 48.8% with the nearest type strains. The genome relatedness is supported by other polyphasic taxonomic data to propose strain KCTC 32190T as a new species in the genus Neoroseomonas with the name Neoroseomonas marina sp. nov. The type strain is strain JC162T (KCTC 32190T = CGMCC1.12364T).

Toxicity of Crude Extracellular Products of Aeromonas hydrophila on Rohu, Labeo rohita (Ham.).

In the present study the haemolytic and proteolytic activity of extracellular products (ECP) secreted from Aeromonas hydrophila (CAHH14 strain) were studied with respect to temperature and different time of incubation as well as its lethal toxicity on rohu, Labeo rohita. The strain was isolated from Catla catla (showing abdominal dropsy symptom) collected from the pond of Central Institute of Freshwater Aquaculture (CIFA), Bhubaneswar, India and was characterized on the basis of biochemical tests. The highest production of haemolysin was achieved when the bacteria was grown at 35°C for 30 h. The proteolytic activity was found to be highest when the bacterium was grown at 30°C for 36 h. The haemolytic and proteolytic toxin produced by Aeromonas hydrophila was found to be lethal to rohu (LD(50) 1.7 × 10(4) cfu/ml). The lethality of ECP was decreased by heating and completely inactivated by boiling at 100°C for 10 min. This indicates that protease activity and haemolytic activity of A. hydrophila ECP was temperature dependant.