Nanosized Hexagonal Boron Nitride and Polyethylene Glycol-Filled Leathers for Applications Demanding High Thermal Insulation and Impact Resistance.

Leather is a niche material used for upholsteries, gloves, and garments due to its high durability, flexibility, and softness properties. The inclusion of nanoparticles in the leather matrix provides multifunctionality for high-performance applications. Herein, we synthesized hexagonal boron nitride (h-BN) nanoparticles via a single-step hydrothermal synthesis and treated the leather after dispersing in polyethylene glycol (PEG) to yield h-BN/PEG-treated leathers. Atomic force microscopy and high-resolution transmission electron microscopy analysis ascertained the particle size of 30-50 nm for as-synthesized h-BN nanoparticles. h-BN nanoparticles along with PEG were successfully incorporated into the leather matrix, and this was confirmed by surface and morphological studies using field emission scanning electron microscopy/energy-dispersive X-ray analysis and Fourier transformed infrared spectroscopy. Leathers treated with h-BN/PEG were studied for insulation against heat and cold, and the results displayed improved thermal insulation properties compared to the control leathers. The dynamic mechanical analysis of control and treated leathers demonstrated higher storage modulus, loss modulus, and tan δ values for h-BN/PEG-treated leathers, signifying an increased energy absorption and dissipation potential, which was further ascertained by the low-velocity drop-weight impact resistance test. Thus, the results of this study open up new prospects for h-BN/PEG-treated leathers in strategic applications demanding high thermal insulation and impact resistance properties.

In vitro probing of oxidized inulin cross-linked collagen-ZrO2 hybrid scaffolds for tissue engineering applications.

Hybrid biomaterials incorporated with active ingredients and metal nanoparticles are gaining more interest owing to their increased wound healing capacity. Here, we report the preparation of hybrid collagen scaffolds stabilized with oxidized inulin and ZrO2 nanoparticles for biomedical applications. The functional group changes in the oxidized inulin were ascertained using FT-IR spectroscopy. The hybrid collagen scaffolds possessed all the basic biomaterial characteristics such as biodegradability, porosity, swelling ability, enzymatic and thermal stability. Particularly, the hydrothermal stability of collagen is enhanced up to 96 °C. The hybrid scaffolds are shown to be biocompatible with stem cells and osteoblast cells. The scratch wound healing assay demonstrates that the hybrid scaffolds can heal the wound up to 60% after 24 h incubation due to their higher cell migration index compared to the native collagen scaffold. The results suggest that the prepared hybrid collagen scaffolds can be used for tissue engineering applications.

Bio-hybrid hydrogel comprising collagen-capped silver nanoparticles and melatonin for accelerated tissue regeneration in skin defects.

Hydrogel-based drug delivery systems have emerged as a promising platform for chronic tissue defects owing to their inherent ability to inhibit pathogenic infection and accelerate rapid tissue regeneration. Here, we fabricated a stable bio-hybrid hydrogel system comprising collagen, aminated xanthan gum, bio-capped silver nanoparticles and melatonin with antimicrobial, antioxidant and anti-inflammatory properties. Highly colloidal bio-capped silver nanoparticles were synthesized using collagen as a reducing cum stabilizing agent for the first time while aminated xanthan gum was synthesized using ethylenediamine treatment on xanthan gum. The synthesized bio-hybrid hydrogel exhibits better gelation, surface morphology, rheology and degelation properties. In vitro assessment of bio-hybrid hydrogel demonstrates excellent bactericidal efficiency against both common wound and multidrug-resistant pathogens and biocompatibility properties. In vivo animal studies demonstrate rapid tissue regeneration, collagen deposition and angiogenesis at the wound site predominantly due to the synergistic effect of silver nanoparticles and melatonin in the hydrogel. This study paves the way for developing biologically functional bio-nano hydrogel systems for promoting effective care for various ailments, including infected chronic wounds.

Elastic compliance and adsorption profiles of Bovine serum albumin at fluid/solid interface in the presence of electrolytes.

Non-trivial topology of proteins under shear suggests that even small structural changes in proteins result in dramatic variations in the mechanical properties and stability. In this study, we have analysed the elastic compliance of solvated bovine serum albumin (BSA) with NaCl,MgCl2, FeCl3 of concentration-ranging from 50 mM to 250 mM using Quartz crystal microbalance with dissipation. The compliance shows a reverse Hofmeister trend (Na + 

Physico-chemical studies of elastic compliance and adsorption of DOPC vesicles and its mixture with charged lipids at fluid/solid interface.

Lipid bilayer mechanics is crucial to membrane dynamics and in design of liposomes for delivery applications. In this work, vesicles of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) (size from 50 nm to 1 µm) and its mixtures with anionic 1,2-dioleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) sodium salt (DOPG) and cationic dimethyldioctadecylammonium bromide (DODAB), have been studied under shear stress at fluid/solid interface and their elastic compliance evaluated. Results show that the rate of spreading of the smaller vesicles (∼70 nm) is about 1.4 times slower than those of larger ones (∼1 µ) and that DOPC has the highest elastic compliance compared with DOPC + DOPG and DOPC + DODAB vesicles. A direct correlation between the elastic compliance and the size of the vesicles shows larger vesicles are more structurally labile during adsorption and subsequent adhesion to solid surfaces than the smaller ones. Specific role of bound water in DODAB is reflected in the lowest elastic compliance of DODAB compared to other lipids. Results show that during the process of adhesion at the fluid/air interface, the vesicles undergo contraction, thereby transmitting mechanical stresses to their microenvironment, which matches the SAXS electron density profiles that indicates larger vesicles have thicker bilayer membranes with larger volume of water compared to the smaller sized ones.

Non-aqueous green solvents improve alpha-amylase induced fiber opening in leather processing.

Severe water deficit and highly polluting effluent generation from leather industries have constantly been pressurizing the tanners to adopt cleaner leather processing systems. The present study aims to minimize the use of water by substituting it with non-aqueous green solvents and also to enhance the enzyme action in alpha-amylase based fiber opening process. The activity of alpha-amylase in select non-aqueous green solvents namely, heptane, polyethylene glycol 200 and propylene glycol is considerably higher by 62, 38 and 31% than in water, respectively. Comparable results are obtained for the catalytic efficiency of alpha-amylase and hence it is further validated in collagen fiber opening trials as well. Scanning electron micrographs, histological images and proteoglycan estimation supported the above findings at 1% alpha-amylase dosage. The final quality of the experimental leathers in terms of physical and bulk properties is comparable to that of control leathers. Recycling studies indicate that it is possible to replace water with green solvents for enzymatic fiber opening with the feasibility to recover more than 85% solvent-enzyme mixture and reuse without any additional alpha-amylase usage. Reduction in pollution load coupled with the efficient catalytic action of enzyme in non-aqueous media favors the present protocol for industrial applications.

Bioengineered Hybrid Collagen Scaffold Tethered with Silver-Catechin Nanocomposite Modulates Angiogenesis and TGF-ß Toward Scarless Healing in Chronic Deep Second Degree Infected Burns.

Management of burn wounds with diabetes and microbial infection is challenging in tissue engineering. The delayed wound healing further leads to scar formation in severe burn injury. Herein, a silver-catechin nanocomposite tethered collagen scaffold with angiogenic and antibacterial properties is developed to enable scarless healing in chronic wounds infected with Pseudomonas aeruginosa under diabetic conditions. Histological observations of the granulation tissues collected from an experimental rat model show characteristic structural organizations similar to normal skin, whereas the open wound and pristine collagen scaffold treated animals display elevated dermis with thick epidermal layer and lack of appendages. Epidermal thickness of the hybrid scaffold treated diabetic animals is lowered to 33 ± 2 µm compared to 90 ± 2 µm for pristine collagen scaffold treated groups. Further, the scar elevation index of 1.3 ± 0.1 estimated for the bioengineered scaffold treated diabetic animals is closer to the normal skin. Immunohistochemical analyses provide compelling evidence for the enhanced angiogenesis as well as downregulated transforming growth factor- ß1 (TGF-ß1) and upregulated TGF-ß3 expressions in the hybrid scaffold treated animal groups. The insights from this study endorse the bioengineered collagen scaffolds for applications in tissue regeneration without scar in chronic burn wounds.

Silica microsphere-resorcinol composite embedded collagen scaffolds impart scar-less healing of chronic infected burns in type-I diabetic and non-diabetic rats.

The existence of diabetes and microbial infection in burn wounds makes the healing process more complex. Herein, we synthesize a collagen based hybrid scaffold incorporated with a silica-resorcinol composite and cross-linked with an oxidized fenugreek seed polysaccharide to stimulate scar-less healing in chronic wounds with type-I diabetes and microbial infection. The spectroscopic analyses of the hybrid scaffolds reveal the chemical and structural integrity of collagen. The hybrid scaffolds are shown to be appropriate for in vivo tissue regeneration through cytocompatibility and hemocompatibility studies. Scaffolds were applied to diabetic albino rats induced with chronically infected burn wounds with respective controls. Histological and immunohistochemical analyses of the granulation tissue collected from the hybrid scaffold treated animal groups showed improved angiogenesis, reepithelialization and TGF-ß3 expression, which eventually led to scar-less wound healing. The results confirm that the prepared hybrid collagen scaffold could be used for effective scar-less wound healing in chronic burn wounds.

A ZnO-curcumin nanocomposite embedded hybrid collagen scaffold for effective scarless skin regeneration in acute burn injury.

Scar formation in severe burn injury is a major health concern. Herein, we developed a hybrid collagen scaffold with an incorporated ZnO-curcumin nanocomposite, which facilitates scarless wound healing. Biocompatibility and hemocompatibility studies unveiled that the hybrid scaffold is apt for in vivo wound healing studies. Histological and immunohistochemical analyses demonstrate that the hybrid scaffold accelerated scarless burn wound healing in albino rats owing to the ZnO-curcumin nanocomposite induced up-regulation of angiogenesis and TGF-ß3 expression. The semi-quantitatively measured scar elevation index of the hybrid scaffold-treated animals is on a par with that of the unwounded or normal skin. The studies suggest that the prepared hybrid biomaterial could be a potential candidate for scarless healing in severe burn injuries.

A Facile Approach to Fabricate Dual Purpose Hybrid Materials for Tissue Engineering and Water Remediation.

Creating hybrid materials with multifunctionality and robust mechanical stability from natural resources is a challenging proposition in materials science. Here, we report the scalable synthesis of hybrid collagen scaffolds using collagen extracted from leather industry wastes and sago starch derived from agro-industry. The hybrid scaffolds were incorporated with TiO2 nanoparticles and cross-linked with oxidized sago starch. The biocompatibility, thermal stability and antimicrobial property of hybrid scaffold enabled its application in burn wound healing demonstrated through albino rat models. The highly porous hybrid scaffolds are shown to be super-compressible, which is typically forbidden in materials of biological origin. We demonstrate that the hybrid scaffolds concurrently display both adsorption and absorption behavior in the removal of oil and dye molecules, respectively from contaminated water. This study paves the way for the development of novel multifunctional and shape recoverable hybrid materials specifically from renewable resources.

Bifunctional Hybrid Composites from Collagen Biowastes for Heterogeneous Applications.

We report the synthesis of an electrically conductive and magnetically active hybrid biocomposite comprising collagen and polyaniline (PAni) as the matrix and iron oxide nanoparticles (IONPs) as the filler through an in situ polymerization technique. Here, the matrix biopolymer, collagen, was extracted from trimmed wastes of animal hides generated from the leather industry. The as-synthesized C/PAni/IONP hybrid biocomposite powder possesses excellent electrical conductivity, thermal stability, and saturation magnetization, thereby providing scope for a wide range of applications. We show that the bifunctional composite has an ability to conduct electrons using a light emitting diode and battery setup, degrade dye under sunlight owing to its inherent photocatalytic activity, and absorb oil from oil-water mixtures with easier collection under magnetic tracking. We also demonstrate that the composite has remarkable electromagnetic interference shielding in the X-band frequency range. The results suggest that biowastes can be converted into useful high-value hybrid materials for applications in catalysis, biological, electronic, and environmental fields, thereby presenting a scalable and sustainable approach.

Collagen-poly(dialdehyde) guar gum based porous 3D scaffolds immobilized with growth factor for tissue engineering applications.

Here we report the preparation of collagen-poly(dialdehyde) guar gum based hybrid functionalized scaffolds covalently immobilized with platelet derived growth factor - BB for tissue engineering applications. Poly(dialdehyde) guar gum was synthesized from selective oxidation of guar gum using sodium periodate. The synthesized poly(dialdehyde) guar gum not only promotes crosslinking of collagen but also immobilizes the platelet derived growth factor through imine bonds. The covalent crosslinking formed in collagen improves thermal, swelling and biodegradation properties of the hybrid scaffolds. The prepared hybrid scaffolds show 3D interconnected honeycomb porous structure when viewed under a microscope. The release of immobilized platelet derived growth factor was seen up to 13th day of incubation thereby proving its sustained delivery. The developed hybrid scaffold leads to a quantum increase in NIH 3T3 fibroblast cell density and proliferation thereby demonstrating its potential for tissue engineering applications.