Silver-doped hydroxyapatite laden chitosan-gelatin nanocomposite scaffolds for bone tissue engineering: an in-vitro and in-ovo evaluation.

Despite the advancements in bone tissue engineering, the majority of implant failures are caused due to microbial contamination. So, efforts are being made to develop biomaterial with antimicrobial property enhancing the regeneration of damaged bone tissue. In the present study, chitosan-gelatin (CG) scaffolds containing silver-doped hydroxyapatite (AgHAP) nanoparticles at 0.5%, 1.0% and 1.5% (w/v) were fabricated by lyophilization technique. The results confirmed the synthesis of AgHAP nanoparticles and showed interconnected porous structure of the nanocomposite scaffolds with 89%-75% porosity. Similarly, the swelling percentage, degradation behavior and compressive modulus of CG-AgHAP nanocomposite scaffolds were 1666%, 40% and 0.7 MPa, respectively. The developed nanocomposite scaffolds revealed better antimicrobial properties and bioactivity. The cell culture studies showed favorable viability of Wharton's jelly stem cells on CG-AgHAP nanocomposite scaffolds. CAM (chorioallantoic membrane) assay determined the angiogenic potential with better visualization of blood vessels in the CAM area. Hence, the obtained results confirmed that CG-AgHAP3 nanocomposite scaffold was the most suitable for bone tissue engineering applications among all scaffolds.

Recent advances in biomacromolecule-based nanocomposite films for intelligent food packaging- A review.

In food packaging, biopolymer films are biodegradable films made from biomacromolecule-based natural materials, while biocomposite films are hybrids of two or more materials, with at least one being biodegradable. Bionanocomposites are different than the earlier ones, as they consist of various nanofillers (both natural and inorganic) in combination with biomacromolecule-based biodegradable materials to make good compostable bionanocomposites. In this regard, a new type of material known as bionanocomposite has been recently introduced to improve the properties and performance of biocomposite films. Bionanocomposites are primarily developed for active packaging, but their use in intelligent packaging is also noteworthy. For example, bionanocomposites developed using a hybrid of anthocyanin and carbon dots as intelligent materials have shown their high pH-sensing properties. The natural nanofillers (like nanocellulose, nanochitosan, nanoliposome, cellulose nanocrystals, cellulose nanofibers, etc.) are being employed to promote the sustainability, degradability and safety of bionanocomposites. Overall, this article comprehensively reviews the latest innovations in bionanocomposite films for intelligent food packaging over the past five years. In addition to packaging aspects, the role of nanofillers, the importance of life cycle assessment (LCA) and risk assessment, associated challenges, and future perspectives of bionanocomposite intelligent films are also discussed.

Cerium oxide nanoparticles disseminated chitosan gelatin scaffold for bone tissue engineering applications.

Cell-free and cell-loaded constructs are used to bridge the critical-sized bone defect. Oxidative stress at the site of the bone defects is a major interference that slows bone healing. Recently, there has been an increase in interest in enhancing the properties of three-dimensional scaffolds with free radical scavenging materials. Cerium oxide nanoparticles (CNPs) can scavenge free radicals due to their redox-modulating property. In this study, freeze-drying was used to fabricate CG-CNPs nanocomposite scaffolds using gelatin (G), chitosan (C), and cerium oxide nanoparticles. Physico-chemical, mechanical, and biological characterization of CG-CNPs scaffolds were studied. CG-CNPs scaffolds demonstrated better results in terms of physicochemical, mechanical, and biological properties as compared to CG-scaffold. CG-CNPs scaffolds were cyto-friendly to MC3T3-E1 cells studied by performing in-vitro and in-ovo studies. The scaffold's antimicrobial study revealed high inhibition zones against Gram-positive and Gram-negative bacteria. With 79 % porosity, 45.99 % weight loss, 178.25 kPa compressive modulus, and 1.83 Ca/P ratio, the CG-CNP2 scaffold displays the best characteristics. As a result, the CG-CNP2 scaffolds are highly biocompatible and could be applied to repair bone defects.

Surgical cotton microfibers loaded with proteins and apatite: A potential platform for bone tissue engineering.

Tissue engineering has emerged as the best alternative to replacing damaged tissue/organs. However, the cost of scaffold materials continues to be a significant obstacle; thus, developing inexpensive scaffolds is strongly encouraged. In this study, cellulose microfibers (C), gelatin (G), egg white (EW), and nanohydroxyapatite (nHA) were assembled into a quaternary scaffold using EDC-NHS crosslinking, followed by freeze-drying method. Cellulose microfibers as a scaffold have only received a limited amount of research due to the absence of an intrinsic three-dimensional structure. Gelatin, more likely to interact chemically with collagen, was used to provide a stable structure to the cellulose microfibers. EW was supposed to provide the scaffold with numerous cell attachment sites. nHA was chosen to enhance the scaffold's bone-bonding properties. Physico-chemical, mechanical, and biological characterization of scaffolds were studied. In-vitro using MG-63 cells and in-ovo studies revealed that all scaffolds were biocompatible. The results of the DPPH assay demonstrate the ability of CGEWnHA to reduce free radicals. The CGEWnHA scaffold exhibits the best properties with 56.84 ± 28.45 µm average pore size, 75 ± 1.4 % porosity, 39.23 % weight loss, 109.19 ± 0.98 kPa compressive modulus, and 1.72 Ca/P ratio. As a result, the constructed CGEWnHA scaffold appears to be a viable choice for BTE applications.

Scaffold Fabrication Techniques of Biomaterials for Bone Tissue Engineering: A Critical Review.

Bone tissue engineering (BTE) is a promising alternative to repair bone defects using biomaterial scaffolds, cells, and growth factors to attain satisfactory outcomes. This review targets the fabrication of bone scaffolds, such as the conventional and electrohydrodynamic techniques, for the treatment of bone defects as an alternative to autograft, allograft, and xenograft sources. Additionally, the modern approaches to fabricating bone constructs by additive manufacturing, injection molding, microsphere-based sintering, and 4D printing techniques, providing a favorable environment for bone regeneration, function, and viability, are thoroughly discussed. The polymers used, fabrication methods, advantages, and limitations in bone tissue engineering application are also emphasized. This review also provides a future outlook regarding the potential of BTE as well as its possibilities in clinical trials.

Sustainable and green manufacturing of gravure printing cylinder for flexible packaging printing application.

Rotogravure printing cylinders are engraved by electro-mechanical engraving (EME) process in India used for printing purpose. But this process has drawbacks of the emissions of hazardous gases, solid and water pollution. EME cylinders are better in cell size, depth and needed higher copper and chrome plating thickness. By laser engraving (LE) copper and chromium thickness were reduced by 75 µm and 5 µm in a cylinder by laser engraving with also a reduction in power consumption and plating time. The carbon footprints were also reduced by 227 g per cylinder with a cost-effective solution for rotogravure printing process.

Influence of mechanical operation on the biodelignification of Leucaena leucocephala by xylanase treatment.

This study aimed at energy reduction during pulping of L. leucocephala by passing the wood chips through an impressafiner followed by xylanase pretreatment. An impressafiner compressed the chips and converted them into spongy materials. Wood chips of L. leucocephala with or without de-structuring and de-structured wood chips followed by enzymatic treatment were subjected to Kraft pulping at different temperatures varying from 135 to 170 °C and active alkali varying from 12 to 20% (as Na2O) to observe effect on screened pulp yield and kappa number. The de-structured wood chips followed by enzymatic treatment produced a pulp yield of 48.2% and kappa number 18.6. L. leucocephala without de-structuring produced a pulp yield of 50.1% and kappa number 23.7. When the pulp was subjected to oxygen delignification to reduce kappa number in the vicinity of 18.6, pulp showed shrinkage by 6.64% compared to Kraft pulp of de-structured wood chips followed by enzymatic treatment. Kraft pulp produced from de-structured wood chips of L. leucocephala followed by enzymatic treatment showed net saving of US$ 163.15 per digester over Kraft pulp produced without de-structuring of wood chips of L. leucocephala. Moreover, the pulp obtained by de-structuring followed by enzymatic treatment showed improvement in pulp brightness and physical strength properties including tensile, tear, and burst index significantly compared to pulp obtained without de-structuring.

Valorization of fruit processing waste to produce high value-added bacterial nanocellulose by a novel strain Komagataeibacter xylinus IITR DKH20.

To date, the production of bacterial nanocellulose (BNC) by standard methods has been well known, while the use of low-cost feedstock as an alternative medium still needs to be explored for BNC commercialization. This study explores the prospect for the use of the different aqueous extract of fruit peel wastes (aE-FPW) as a nutrient and carbon source for the production of BNC. Herein, this objective was accomplished by the use of a novel, high- yielding strain, isolated from rotten apple and further identified as Komagataeibacter xylinus IITR DKH20 using 16 s rRNA sequencing analysis. The physicochemical properties of BNC matrix collected from the various aE-FPW mediums were similar or advanced to those collected with the HS medium. Statistical optimization of BNC based on Central Composite Design was performed to study the effect of significant parameters and the results demonstrated that the BNC yield (11.44 g L-1) was increased by 4.5 fold after optimization.

Cotton pulp for bone tissue engineering.

Cellulose, a polysaccharide of ß (1-4) linked D-glucose units, is a cheap, eco-friendly and most abundant natural polymer on this planet. Among various cellulosic materials, cotton cellulose is readily available, lignin-free, FDA approved, and widely used in the medical field because of its higher degree of biocompatibility and non-cytotoxic nature. Though cotton cellulose showed essential material properties for scaffold design, the least priority had been given to this material. The present study aimed at exploring the fabrication of scaffold using cotton microfibers for bone tissue engineering application. The study also aimed at improving the mechanical, physio-chemical and osteogenic properties of the microfibrous scaffold by crosslinking with citric acid and further modified with gelatin. FTIR indicated some interactions between cellulose, citric acid and gelatin within the scaffolds, while XRD results demonstrated the crystalline nature of scaffolds. Porosity and swelling studies demonstrated that all scaffolds are hydrophilic and porous. The microporous interconnected network of scaffolds was confirmed by FESEM. FESEM micrographs and MTT assay confirmed that all scaffolds were nontoxic to MG 63. Based on findings, it was concluded that gelatin coated cotton cellulose microfibers crosslinked with citric acid scaffold would be a potential template for bone tissue engineering.

Studies on bacterial cellulose produced by a novel strain of Lactobacillus genus.

The present study aimed to explore a novel attribute of the bacterium Lactobacillus hilgardii IITRKH159, isolated from Sapodilla, which was found to produce Bacterial cellulose. The compositional analysis of BC was carried out by HPLC system using pre-column derivatization with 1-phenyl-3-methyl-5-pyrazolone showed that it consisted of glucan. The Physiochemical study of BC showed that it had bacterial nano-cellulose like structure, immensely pure, highly crystalline (90.25%) and significantly enriched with Iα form of cellulose. Additionally, FE-SEM and TEM of the BC revealed the morphological similarities with bacterial nano-cellulose due to the presence of a reticulated structure consisting of nano-sized fibrils with an average width of 45 nm. The effect of different carbon sources was analyzed to evaluate BC production and demonstrated the production of 7.23 ±â€¯0.59 g L-1 BC with conversions yield (0.30 g BC/g sugar) and productivity (0.45 ±â€¯0.15 g L-1 d-1) in a modified Y-medium after 16 days of cultivation.

Rice straw fermentation by Schizophyllum commune ARC-11 to produce high level of xylanase for its application in pre-bleaching.

Rice straw is valuable resource that has been used as substrate for cost effective production of xylanase under solid-state fermentation by a newly isolated white rot fungi, S. commune ARC-11. Out of eleven carbon sources tested, rice straw was found most effective for the induction of xylanase that produced 4288.3 IU/gds of xylanase by S. commune ARC-11. Maximum xylanase production (6721.9 IU/gds) was observed on 8th day of incubation at temperature (30 °C), initial pH (7.0) and initial moisture content (70.0%). The supplementation of ammonium sulphate (0.08% N, as available nitrogen) enhanced the xylanase production up to 8591.4 IU/gds. The xylanase production by S. commune ARC-11 was further improved by the addition of 0.10%, (w/v) of Tween-20 as surfactant. The maximum xylanase activities were found at pH 5.0 and temperature 55 °C with a longer stability (180 min) at temperature 45, 50 and 55 °C. This xylanase preparation was also evaluated for the pre-bleaching of ethanol-soda pulp from Eulaliopsis binata. An enzyme dosage of 10 IU/g of xylanase resulted maximum decrease in kappa number (14.51%) with a maximum improvement 2.9% in ISO brightness compared to control.

Production of crude enzyme from Aspergillus nidulans AKB-25 using black gram residue as the substrate and its industrial applications.

The production of crop residues in India is estimated to be about 500-550 million tons annually. It is estimated that about 93 million tons of crop residues is burnt annually which is not only wastage of valuable biomass resources but pollution of the environment with the production of green house gases also. Among different low cost crop residues, black gram residue as the substrate produced maximal endoglucanase, FPase, and ß-glucosidase activities from Aspergillus nidulans AKB-25 under solid-state fermentation. During optimisation of cultural parameters A. nidulans AKB-25 produced maximal endoglucanase (152.14 IU/gds), FPase (3.42 FPU/gds) and xylanase (2441.03 IU/gds) activities. The crude enzyme was found effective for the saccharification of pearl millet stover and bio-deinking of mixed office waste paper. The crude enzyme from A. nidulans AKB-25 produced maximum fermentable sugars of 546.91 mg/g from alkali-pretreated pearl millet stover by saccharification process at a dose of 15 FPU/g of substrate. Pulp brightness and deinking efficiency of mixed office waste paper improved by 4.6% and 25.01% respectively and mitigated dirt counts by 74.70% after bio-deinking. Physical strength properties like burst index, tensile index and double fold number were also improved during bio-deinking of mixed office waste paper.

Bio-conventional bleaching of kadam kraft-AQ pulp by thermo-alkali-tolerant xylanases from two strains of Coprinellus disseminatus for extenuating adsorbable organic halides and improving strength with optical properties and energy conservation.

Two novel thermo-alkali-tolerant crude xylanases namely MLK-01 (enzyme-A) and MLK-07 (enzyme-B) from Coprinellus disseminatus mitigated kappa numbers of Anthocephalus cadamba kraft-AQ pulps by 32.5 and 34.38%, improved brightness by 1.5 and 1.6% and viscosity by 5.75 and 6.47% after (A)XE(1) and (B)XE(1)-stages, respectively. The release of reducing sugars and chromophores was the highest during prebleaching of A. cadamba kraft-AQ pulp at enzyme doses of 5 and 10 IU/g, reaction times 90 and 120 min, reaction temperatures 75 and 65°C and consistency 10% for MLK-01 and MLK-07, respectively. MLK-07 was more efficient than MLK01 in terms of producing pulp brightness, improving mechanical strength properties and reducing pollution load. MLK-01 and MLK-07 reduced AOX by 19.51 and 42.77%, respectively at 4% chlorine demands with an increase in COD and colour due to removal of lignin carbohydrates complexes. A. cadamba kraft-AQ pulps treated with xylanases from MLK-01 to MLK-07 and followed by CEHH bleaching at half chlorine demand (2%) showed a drastic reduction in brightness with slight improvement in mechanical strength properties compared to pulp bleached at 4% chlorine demand. MLK-01 reduced AOX, COD and colour by 43.83, 39.03 and 27.71% and MLK-07 by 38.34, 40.48 and 30.77%, respectively at half chlorine demand compared to full chlorine demand (4%). pH variation during prebleaching of A. cadamba kraft-AQ pulps with strains MLK-01 and MLK-07 followed by CEHH bleaching sequences showed a decrease in pulp brightness, AOX, COD and colour with an increase in mechanical strength properties, pulp viscosity and PFI revolutions to get a beating level of 35 ± 1 °SR at full chlorine demand.

Bio-conventional bleaching of wheat straw soda-AQ pulp with crude xylanases from SH-1 NTCC-1163 and SH-2 NTCC-1164 strains of Coprinellus disseminatus to mitigate AOX generation.

Two novel cellulase-poor xylanases from Coprinellus disseminatus SH-1 NTCC-1163 (enzyme-A) and SH-2 NTCC-1164 (enzyme-B) produced under solid-state fermentation mitigated kappa number of wheat straw soda-AQ pulps by 24.38 and 27.94% respectively after XE stages. The release of reducing sugars and chromophores was highest for both the enzymes at 10IU/g and reaction time 180min for 55°C at variable consistencies that is, 10% for enzyme-A and 5% for enzyme-B. (A)XECEHH and (B)XECEHH sequences improved brightness by 5.17 and 2.58% respectively at 4.5% chlorine charge. AOX in (A)XECEHH and (B)XECEHH sequences reduced by 56.11 and 55.75% respectively at 4.5% chlorine charge and 68.34 and 67.98% respectively at 2.25% chlorine charge respectively compared to control. Both the enzymes showed improvement in double fold and tear index with a decrease in burst and tensile index. SEM showed peeling, cracking and delamination in fibers due to enzyme treatment thus facilitating the penetration of bleach chemicals.

Production of high level of cellulase-poor xylanases by wild strains of white-rot fungus Coprinellus disseminatus in solid-state fermentation.

The production, optimisation and partial characterisation of xylanases from newly isolated wild strains of Coprinellus disseminatus was performed in solid-state fermentation. Strains SH-1 and SH-2 showed high xylanase (727.78 and 227.99 IU/mL) with very low CMCase (0.925 and 0.660 IU/mL) and laccase (0.640 and 0.742 U/mL) activities at incubation time seven days, 37 degrees C and initial pH 6.4, using yeast extract as nitrogen source and cheap substrate (wheat bran), which increased the cost effectiveness of the process. Crude cellulase-poor xylanases obtained from test strains showed maximum activities at 55 degrees C and pH 6.4 and retained 32.64 (SH-1) and 35.03% (SH-2) activity at pH 8 and 43.01 (SH-1) and 25.00% (SH-2) activity at 65 degrees C. As test strains produced high level of cellulase-poor xylanases, which were active over a wide range of temperature and pH, these enzymes might be used as pulp biobleaching agents.