Fluorescent xylitol carbon dots: A potent antimicrobial agent and drug carrier.

Biomolecular carbon dots (CDs) have immense potential for various industries due to exceptional bioactivity, biocompatibility, low toxicity, and biodegradability. In the present work xylitol (Xlt), a natural sweetener produced by microbial fermentation of sugarcane bagasse (71.98% conversion) has been used for CDs preparation by microwave-assisted carbonization in the presence of ethylene diamine (EDA). The resultant xylitol carbon dots (XCDs) were irregular shaped, rough with an average size of 8.88 nm and exhibiting fluorescence between 400 and 450 nm. The presence of EDA preserves the native chemical structure of Xlt even after exposure to microwaves. Purified XCDs were conjugated (AM-XCD) with ketoconazole and tetracycline for fungi and bacteria, respectively. In comparison to Xlt, XCDs have higher inhibitory potential and reduced dosage size of antimicrobials against Cryptococcus neoformans, Candida albicans, Streptococcus pyogenes, and Escherichia coli by 75%, 75%, 87.50%, and 50%, respectively. For Listeria monocytogenes and Salmonella typhi also inhibitory potential was increased by 14.68% and 21.38%. Increased efficacy advocated the improved drug delivery in the presence of XCDs. However, no inhibitory effect was recorded against DU145 (human prostate cancer) and HCT-15 (human colon adenocarcinoma) cell lines. The findings of the current work suggested the possible use of Xlt as an important antimicrobial agent besides an efficient drug carrier in healthcare.

Lactoferrin-modified Betulinic Acid-loaded PLGA nanoparticles are strong anti-leishmanials.

Visceral Leishmaniasis (VL), caused by the protozoan parasite Leishmania donovani, is a potentially fatal disease. The only orally bioavailable drug miltefosine is toxic and the effective liposomal Amphotericin B (AmBisome) is limited by its prohibitive cost and requirement for parenteral administration. Therefore, finding a new potential drug candidate and an alternative delivery system is imperative. We report that Betulinic acid (BA), a pentacyclic triterpenoid from Betula alba bark, was loaded onto uniformly spherical PLGA nanoparticles (BANPs; diameter 187.5 ±â€¯5.60 nm) coated with Lactoferrin (Lf-BANPs). The amastigotes count in macrophages was more effectively reduced by Lf-BANP than BA and BANP. Lf-BANPs reduced the pro-parasitic, anti-inflammatory cytokine IL-10, but increased nitric oxide (NO), production in L. donovani-infected macrophages indicating that Lf-BANP possesses a significant anti-leishmanial activity.

Osteoconductive Amine-Functionalized Graphene-Poly(methyl methacrylate) Bone Cement Composite with Controlled Exothermic Polymerization.

Bone cement has found extensive usage in joint arthroplasty over the last 50 years; still, the development of bone cement with essential properties such as high fatigue resistance, lower exothermic temperature, and bioactivity has been an unsolved problem. In our present work, we have addressed all of the mentioned shortcomings of bone cement by reinforcing it with graphene (GR), graphene oxide (GO), and surface-modified amino graphene (AG) fillers. These nanocomposites have shown hypsochromic shifts, suggesting strong interactions between the filler material and the polymer matrix. AG-based nanohybrids have shown greater osteointegration and lower cytotoxicity compared to other nanohybrids as well as pristine bone cement. They have also reduced oxidative stress on cells, resulting in calcification within 20 days of the implantation of nanohybrids into the rabbits. They have significantly reduced the exothermic curing temperature to body temperature and increased the setting time to facilitate practitioners, suggesting that reaction temperature and settling time can be dynamically controlled by varying the concentration of the filler. Thermal stability and enhanced mechanical properties have been achieved in nanohybrids vis-à-vis pure bone cement. Thus, this newly developed nanocomposite can create natural bonding with bone tissues for improved bioactivity, longer sustainability, and better strength in the prosthesis.

Drug functionalized microbial polysaccharide based nanofibers as transdermal substitute.

In order to promote the natural healing process, drug-functionalized nanofibrous transdermal substitute was fabricated using gellan as chief polymer and polyvinyl alcohol (PVA) as supporting polymer via electrospinning technique. These fabricated nanofibers physiochemically mimic the extracellular matrix (ECM) which supports the cell growth. For neo-tissue regeneration in a sterilized environment, amoxicillin (Amx) was entrapped within these nanofibers. Entrapment of Amx in the nanofibers was confirmed by FESEM, FTIR, XRD and TG analysis. In vitro cell culture studies revealed that the fabricated non-cytotoxic nanofibers promoted enhance cell adherence and proliferation of human keratinocytes. A preliminary in vivo study performed on rat model for full thickness skin excision wound demonstrated the prompt re-epithelialization in early phase and quicker collagen deposition in later phases of wound healing in case of Amx-functionalized gellan/PVA nanofibers. Data collectively confirmed the potential usage of gellan based electrospun nanofibers as transdermal substitute for faster skin restoration.

Development of Anisotropic Electrically Conductive GNP-Reinforced PCL-Collagen Scaffold for Enhanced Neurogenic Differentiation under Electrical Stimulation.

The internal electric field of the human body plays a crucial role in regulating various biological processes, such as, cellular interactions, embryonic development and the healing process. Electrical stimulation (ES) modulates cytoskeleton and calcium ion activities to restore nervous system functioning. When exposed to electrical fields, stem cells respond similarly to neurons, muscle cells, blood vessel linings, and connective tissue (fibroblasts), depending on their environment. This study develops cost-effective electroconductive scaffolds for regenerative therapy. This was achieved by incorporating carboxy functionalized graphene nanoplatelets (GNPs) into a Polycaprolactone (PCL)-collagen matrix. ES was used to assess the scaffolds' propensity to boost neuronal differentiation from MSCs. This study reported that aligned GNP-reinforced PCL-Collagen scaffolds demonstrate substantial MSC differentiation with ES. This work effectively develops scaffolds using a simple, cost-effective synthesis approach. The direct coupling approach generated a homogeneous electric field to stimulate cells cultured on GNP-reinforced scaffolds. The scaffolds exhibited improved mechanical and electrical characteristics, as a result of the reinforcement with carbon nanofillers. In vitro results suggest that electrical stimulation helps differentiation of mesenchymal stem-like cells (MSC-like) towards neuronal. This finding holds great potential for the development of effective treatments for tissue injuries related to the nervous system.

Engineered andrographolide nanoparticles mitigate paracetamol hepatotoxicity in mice.

PURPOSE: Paracetamol (acetaminophen, APAP) overdose is often fatal due to progressive and irreversible hepatic necrosis. The aim of this work was to design Andrographolide (AG) loaded nanoparticles to prevent similar hepatic necrosis. METHODS: Functionalized AG-loaded PLGA nanoparticles carrying different densities of heparin were prepared following a facile emulsion solvent evaporation technique. Nanoparticle morphology, loading and release kinetics were studied. Hepatic localization of the nanoparticles was investigated in both normal and APAP damaged conditions using FITC fluorescent probe. Different serum parameters and liver histopathology were further examined as indicators of hepatic condition before and after treatment. RESULT: A collection of heparin functionalized AG-loaded PLGA nanoparticles were designed. Low amount of heparin on the particle surface could rapidly localize the nanoparticles up to the liver. The new functionalized AG nanoparticles affect efficient hepatoprotection in experimental mouse APAP overdose conditions. AG nanoparticle hepatoprotection was due to the rapid regeneration of antioxidant capacity and hepatic GSH store. CONCLUSIONS: Engineered nanoparticles loaded with AG provided a fast protection in APAP induced acute liver failure.

Poly(DL-lactide-co-glycolic acid) nanoparticle design and payload prediction: a molecular descriptor based study.

Polymer nanoparticles are veritable tools for pharmacokinetic and therapeutic modifications of bioactive compounds. Nanoparticle technology development and scaling up are however often constrained due to poor payload and improper particle dissolution. This work was aimed to develop descriptor based computational models as prior art tools for optimal payload in polymeric nanoparticles. Loading optimization experiments were carried out both in vitro and in-silico. Molecular descriptors generated in three different platforms DRAGON, molecular operating environment (MOE) and VolSurf+ were used. Multiple linear regression analysis (MLR) provided computation models which were further validated based on goodness of fit statistics and correlation coefficients (DRAGON, R(2)=0.889, Q(2)=0.657, R(2)(pred)=0.616; MOE, R(2)=0.826, Q(2)=0.572, R(2)(pred)=0.601; and VolSurf+, R(2)=0.818, Q(2)=0.573, R(2)(pred)=0.653). Pharmacophore space modeling studies were carried out in order to understand the fundamental molecular interactions necessary for drug loading in poly(DL-lactide-co-glycolic acid). The space modeling study (R(2)=0.882, Q(2)=0.662, R(2)(pred)=0.725, Δ(cost)=108.931) indicated that hydrogen bond acceptors and ring aromatic features are of primary significance for nanoparticle drug loading. Results of in vitro experiments have also confirmed the fact as a viable prognosis in case of nanoparticle payload. Polymeric nanoparticles payload prediction can therefore be a useful tool for wider benefits at the preformulation stages itself.

Meropenem loaded 4-arm-polyethylene-succinimidyl-carboxymethyl ester and hyaluronic acid based bacterial resistant hydrogel.

Developing an ideal vitreous substitute/implant is a current challenge. Moreover, implants (e.g., heart valves and vitreous substitutes), are associated with a high risk of bacterial infection when it comes in contact with cells at implant site. Due to infection, many implants fail, and the patient requires immediate surgery and suffers from post-operative problems. To overcome these problems in vitreous implants, we developed a bacterial resistant vitreous implant, where meropenem (Mer), an antibiotic, has been incorporated in a hydrogel prepared by crosslinking HA (deacetylated sodium hyaluronate) with 4-arm-polyethylene-succinimidyl-carboxymethyl-ester (PESCE). The HA-PESCE hydrogel may serve as a suitable artificial vitreous substitute (AVS). The pre-gel solutions of HA-PESCE without drug and with the drug are injectable through a 22 G needle, and the gel formation occurred in approx. 3 min: it indicates its suitability for in-situ gelation through vitrectomy surgery. The HA-PESCE hydrogel depicted desired biocompatibility, transparency (>90 %), water content (96 %) and sufficient viscoelasticity (G' >100 Pa) calculated after 1 month in-vitro, which are suitable for vitreous substitute. The HA-Mer-PESCE hydrogel showed improved biocompatibility, suitable transparency (>90 %), high water content (96 %), and suitable viscoelasticity (G' >100 Pa) calculated after 1 month in-vitro, which are suitable for vitreous substitute. Further, hydrogel strongly inhibits the growth of bacteria E.coli and S.aureus. The drug loaded hydrogel showed sustained in-vitro drug release by the Fickian diffusion-mediated process (by Korsmeyer-Peppas and Peppas Sahlin model). Thus, the developed hydrogel may be used as a potential bacterial resistant AVS.

Biosynthesis of folic acid appended PHBV modified copper oxide nanorods for pH sensitive drug release in targeted breast cancer therapy.

Multifunctional nanoplatforms as nanocarriers have attracted the interest of many scientists because they can achieve greater therapeutic effect in anticancer drug delivery to tumors with potential to improve cancer treatment, while currently available therapies are nonspecific and ineffectual. In present study, notable cancer therapeutic strategy which combines PEG functionalized poly (3-hydroxybutyric acid-co-hydroxyvaleric acid) (PHBV) nanospheres decorated with folic acid for delivery of paclitaxel (PTX) drug conjugated with copper oxide (CuO) nanoparticles (NPs) is proposed. Moreover, PTX loading with CuO NPs in PHBV nanosphere was done to increase its solubility and analyze its apoptotic effects in human breast cancer (MCF-7) cells. The pH-sensitive CuO-PTX@PHBV-PEG-FA nanosystem was successfully developed, as evidenced by number of characterizations. Resultant CuO-PTX@PHBV-PEG-FA NPs were 148.93 ± 10.5 nm in size, having 0.206 PDI, with -20.3 ± 0.6 mV zeta potential. MTT assay in MCF-7 cells was used to assess cell viability, while anticancer potential of CuO-PTX@PHBV-PEG-FA nanosystem was confirmed through different staining techniques. According to in vitro studies, FA-conjugated PHBV modified CuO-PTX targeted nanoparticles exhibited higher anticancer effect than free PTX probably due to binding interaction of folate receptor with cells that overexpress the target. This nanosystem has the potential to be a promising breast cancer treatment agent.

Enhanced neurogenic differentiation on anisotropically conductive carbon nanotube reinforced polycaprolactone-collagen scaffold by applying direct coupling electrical stimulation.

Electrical stimulation is conducive to neural regeneration. Different types of stimuli propagation patterns are required for regenerating cells in peripheral and central nervous systems. Modulation of the pattern of stimuli propagation cannot be achieved through external means. Reinforcing scaffolds, with suitably shaped conductive second phase materials, is a promising option in this regard. The present study has taken the effort of modulating the pattern (arrangement) of reinforced phase, namely multiwalled carbon nanotubes (MWCNT), in a biodegradable scaffold made of PCL-collagen mixture, by applying an external electric field during curing. Because of their extraordinary physical properties, MWCNTs have been selected as nano-reinforcement for this study. The nature of reinforcement affects the electrical conductivity of the scaffold and also determines the type of cell it can support for regeneration. Further, electrical stimulation, applied during incubation, was observed to have a positive influence on differentiating neural cells in vitro. However, the structure of the nano-reinforcement determined the differentiated morphology of the cells. Reinforced MWCNTs being tubes, imparted bipolarity to the cells. Therefore, these scaffolds, coupled with electrical stimulation possess significant potential to be used for directional regeneration of the nerves.

Salivary microbial dysbiosis may predict lung adenocarcinoma: A pilot study.

BACKGROUND: Adenocarcinoma is a more common type of Non-small cell lung cancer (NSCLC). Lung cancer showed a statistically significant increment in the Kamrup Urban district of Assam, Tripura, Sikkim, and Manipur of India. The goal of our pilot study is to identify non-invasive microbial biomarkers to detect lung adenocarcinoma (LAC). MATERIAL AND METHODS: DNA extraction from saliva samples of five LAC patients and five healthy controls was performed by Qiagen DNeasy blood and tissue kit using Lysozyme (3mg/ml) treatment. 16S rRNA genes of distinct regions (V3-V4) were amplified from saliva DNA by PCR. Paired-end sequencing targeting the V3-V4 region of the 16S rRNA gene has been performed on the Illumina MiSeq platform. Raw sequences were analyzed using the QIIME(Quantitative Insights Into Microbial Ecology) software package. RESULTS: Our preliminary results showed that Rothia mucilaginosa, Veillonella dispar, Prevotella melaninogenica, Prevotella pallens, Prevotella copri, Haemophilus parainfluenzae, Neisseria bacilliformis and Aggregatibacter segnis were significantly elevated in saliva of LAC which may serve as potential non-invasive biomarkers for LAC detection. Functional prediction analysis showed that bacterial genes involved in glycosyltransferase, peptidases, amino sugar, and nucleotide sugar metabolism, starch and sucrose metabolism were significantly enriched in LAC. CONCLUSION: These salivary bacteria may contribute to the development of LAC by increasing expression of glycosyltransferase and peptidases. However to understand their role in pathobiology, studies are required to perform in large cohort.

Cellulose nanocrystals­silver nanoparticles-reduced graphene oxide based hybrid PVA nanocomposites and its antimicrobial properties.

Towards fabricating a hybrid biodegradable multifunctional nanocomposite, cellulose nanocrystal (CNC), reduced graphene oxide (rGO) and silver (Ag) nanoparticles were reinforced into polyvinyl alcohol (PVA) polymer matrix. One-step reduction process was followed, composed of reducing graphene oxide (GO) and silver nitrate (AgNO3) into rGO and Ag nanoparticles through hydrazine hydrate (chemical reduction method), respectively. Uniformly dispersed CNC, rGO and Ag nanoparticles in PVA matrix led to an increment in modulus by 184% of PVA demonstrating the reinforcement outcome of CNC, rGO and Ag. PVA/CNC/rGO/Ag nanocomposite showed the Ag+ ions sustained release from PVA studied using Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). The incorporation and elemental composition of CNC, rGO and Ag nanoparticles into nanocomposite were interpreted through FTIR (Fourier Transform Infrared Spectroscopy) and XPS (X-ray photoelectron spectroscopy) technique, respectively. All prepared nanocomposites with different wt% of Ag (PVA, PVA/CNC, PVA/CNC/rGO/Ag) were non-toxic to HEK-293 cell line and exhibited improved antibacterial property against E. coli and S. aureus due to a combination of Ag+ ions (release from Ag nanoparticles) and rGO (having antibacterial effect). Thus, the combined effect of CNC, rGO and Ag in PVA matrix distinctively resulted into a multifunctional hybrid nanocomposite for potential use in tissue engineering and packaging applications.

3-D macro/microporous-nanofibrous bacterial cellulose scaffolds seeded with BMP-2 preconditioned mesenchymal stem cells exhibit remarkable potential for bone tissue engineering.

Bone repair using BMP-2 is a promising therapeutic approach in clinical practices, however, high dosages required to be effective pose issues of cost and safety. The present study explores the potential of low dose BMP-2 treatment via tissue engineering approach, which amalgamates 3-D macro/microporous-nanofibrous bacterial cellulose (mNBC) scaffolds and low dose BMP-2 primed murine mesenchymal stem cells (C3H10T1/2 cells). Initial studies on cell-scaffold interaction using unprimed C3H10T1/2 cells confirmed that scaffolds provided a propitious environment for cell adhesion, growth, and infiltration, owing to its ECM-mimicking nano-micro-macro architecture. Osteogenic studies were conducted by preconditioning the cells with 50 ng/mL BMP-2 for 15 min, followed by culturing on mNBC scaffolds for up to three weeks. The results showed an early onset and significantly enhanced bone matrix secretion and maturation in the scaffolds seeded with BMP-2 primed cells compared to the unprimed ones. Moreover, mNBC scaffolds alone were able to facilitate the mineralization of cells to some extent. These findings suggest that, with the aid of 'osteoinduction' from low dose BMP-2 priming of stem cells and 'osteoconduction' from nano-macro/micro topography of mNBC scaffolds, a cost-effective bone tissue engineering strategy can be designed for quick and excellent in vivo osseointegration.

A highly transparent tri-polymer complexin situhydrogel of HA, collagen and four-arm-PEG as potential vitreous substitute.

There is a requirement of removal and replacement of vitreous for various ophthalmic diseases, e.g. retinopathy and retinal detachment. Clinical tamponades, e.g. silicone oil and fluorinated gases are used but limited due to their toxicity and some complications. A lot of polymer-based materials have been tested and proposed as vitreous substitute, but till date, there is no ideal vitreous substitute available. Thus, it requires to develop an improved vitreous substitute which will be highly suitable for vitreous replacement. We have developed tri-polymer complexin situhydrogels by crosslinking among hyaluronic acid (HA), collagen (Coll) and four-arm-polyethylene glycol (PEG). All the developed hydrogels are biocompatible with NIH 3T3 mouse fibroblast cells, having pH in the range 7-7.44 and refractive index in the range 1.333-1.345. The developed hydrogels are highly transparent, showing transmittance >97%. FTIR study shows that the hydrogel was crosslinked by amide bond formation between HA and PEG, and between Coll and PEG. The rheological study shows that all the developed hydrogels exhibit viscoelastic behavior and all the hydrogels have storage modulus values (>100 pa) which is greater than loss modulus values-indicating sufficient elasticity for vitreous application. The elastic nature of the hydrogel increases with the increase in PEG concentration. The gel is formed in between 2 and 3 min-indicating its applicationin situ. The viscosity of the developed hydrogels shows shear thinning behavior. The pre-gel solution of the hydrogel is injectable through a 22 G needle-indicating its applicationin situthrough vitrectomy surgery. All the hydrogels are hydrophilic and have water content of 96% approximately. Thus, the results show the positive properties for its application as a potential vitreous substitute.

Functionally gradient magnesium-based composite for temporary orthopaedic implant with improved corrosion resistance and osteogenic properties.

Magnesium (Mg) is a potential alternative for conventional orthopaedic implant materials owing to its biodegradation behavior and physical characteristics similar to natural human bone. Due to its biomimetic mechanical attributes, Mg in orthopaedic applications could reduce the risk of the 'stress shielding effect'. However, the major limitation of Mg is its high in-vivo corrosion rate. Thermal sprayed coatings of osteoconductive ceramics like hydroxyapatite (HA) have been explored as a potential solution, albeit with limited success due to the low melting point of Mg, which restricts the ease of fabricating surface-adherent ceramic coating. The present study focuses on overcoming this limitation through a Mg-HA functionally gradient material (FGM) system, which is expected to provide a highly corrosion-resistant surface and uniform mechanical integrity throughout the structure. In addition to corrosion resistance, the FGM system has improved biocompatibility and osteoconductivity without compromising its mechanical stability. The FGM, with a compositional gradient of Mg-HA composite, consisting of Mg at the core and increasing HA towards the outer layer, has been fabricated through spark plasma sintering. Mechanical properties of the overall structure were better than those of the best individual composite. More importantly, corrosion resistance of the FGM structure was significantly improved (~154%) as compared to individual composites. In addition, alkaline phosphatase activity, osteogenic gene expression and cell viability, all pertaining to efficient osteogenic differentiation, were enhanced for FGM and 15 wt% HA reinforced composites. These observations suggest that the FGM structure is promising for temporary biodegradable orthopaedic implants.

Synthesis, characterization and investigation of synergistic antibacterial activity and cell viability of silver-sulfur doped graphene quantum dot (Ag@S-GQDs) nanocomposites.

The excessive use of traditional antibiotic and antibacterial agents has globally increased the growth of antibiotic-resistant bacteria that poses serious health risks. Therefore, the development of new generation antibacterial or antimicrobial agents for effective inhibition of bacterial growth is highly desired. In this study, we report a facile one-step synthesis approach for the preparation of a nanocomposite composed of silver nanoparticles (AgNPs) decorated with sulfur-doped graphene quantum dots (S-GQDs). The nanocomposite was comprehensively characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-vis absorption spectra, Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The characterization results demonstrated that the AgNPs were closely and uniformly surrounded by the S-GQDs, and consequently, this ensured the dispersion and stability of the so formed nanocomposite (Ag@S-GQDs). Further, the antibacterial activity of the Ag@S-GQDs nanocomposite was investigated and compared with bare S-GQDs and AgNPs against Gram-positive S. aureus (MTCC 737) and Gram-negative P. aeruginosa (MTCC 424) bacteria using macrodilution and agar well diffusion methods. Minimum inhibitory concentration (MIC) values of 70 and 35 µg mL-1 of the Ag@S-GQDs nanocomposite were found to be sufficient to hinder the growth of P. aeruginosa and S. aureus. A fractional inhibition concentration (FIC) index below 0.5 confirmed the existence of a synergistic effect between AgNPs and S-GQDs in the Ag@S-GQDs nanocomposite. In addition, the cytotoxicity of the Ag@S-GQDs nanocomposite, AgNPs and S-GQDs was also investigated using HEK 293 cell lines. Interestingly, the Ag@S-GQDs nanocomposite exhibited superior cell viability as compared to AgNPs and S-GQDs. These improved antibacterial and biocompatibility data demonstrate that the Ag@S-GQDs nanocomposite can serve as a promising antibacterial agent for industry to fabricate next-generation self-sterile textiles, antibacterial coatings and useful health care products supporting cell viability.

In-situ measurement of cellular microenvironments in a microfluidic device.

We report on the integration of optical microsensors into a cell culture microchannel device. We demonstrate the possibility of measuring the glucose and oxygen concentrations in the microenvironment of the mammalian cells cultured in a microchannel device. Furthermore, cell proliferation and morphology could be monitored microscopically while these measurements were being made. Through the use of multiple sensors along the length of the microchannel, concentration gradients of various metabolites, such as oxygen, as well as the effects of cell uptake and perfusion rate of growth medium on these gradients could be studied. As such, the system allowed real-time observations of the cells' response to their chemical microenvironment. Our approach allows cell culture and cell assays to be performed simultaneously in an integrated microchannel system with potential applications as a research tool or drug screening method.

Alkali pretreatment of wheat straw followed by microbial hydrolysis for bioethanol production.

The combination of NaOH pretreatment and microorganisms isolated from termite was used for releasing wrapped polysaccharides from wheat straw biomass matrix. Different concentrations of NaOH (1%, 3%, 5%, 7% and 10%) were considered to remove lignin and to release polysaccharides as a pretreatment method at 80°C for 4 h before subjecting it to microbial hydrolysis. Data obtained from compositional analysis of pretreated wheat straws show that a significant amount of cellulose and lignin were released after NaOH pretreatments. The amount of cellulose and lignin released was increased with increasing concentration of NaOH in the pretreatment solution. Further analysis of X-Ray diffraction, field emission scanning electron microscope and Fourier transform infrared spectroscopy confirms the removal of lignin and release of cellulose. About 69.5% of lignin was solubilized and 72.67% of cellulose was released after 10% NaOH pretreatment which was the maximum. Data from spectrophotometric analysis of reducing sugar by the 3,5-dinitrosalycilic acid method show that 83.68% (0.706 g/100 ml) of polysaccharides were converted to glucose and xylose by isolated bacteria after the 15th day of hydrolysis.

Isolation and Characterization of Novel Lignolytic, Cellulolytic, and Hemicellulolytic Bacteria from Wood-Feeding Termite Cryptotermes brevis.

In a natural ecosystem, various organisms digest and hydrolyze lignocellulose biomass efficiently. Termites are one of them. They digest lignocellulose biomass with the help of symbiotic microorganisms in their gut. Therefore, termites gut may harbor potential sources of microorganisms capable to degrade lignocellulose biomass. In this study, termite gut microbiomes of Cryptotermes brevis species were isolated and identified for their capability to degrade lignin and polysaccharides. Alkali lignin, carboxymethylcellulose, and xylan were used as the only carbon sources in the medium to isolate lignin-, cellulose-, and hemicellulose-degrading bacteria. By this method, two bacteria strains, Bacillus sp. BMP01 and Ochrobactrum oryzae BMP03 strain were isolated and identified. Bacillus sp. BMP01 strain has capabilities to hydrolyze carboxymethylcellulose and xylan to glucose and xylose, respectively. This strain showed high xylanase activity (about 0.21 U/ml) and carboxymethyl cellulase activity (about 0.25 U/ml). The ability to hydrolyze both carboxymethylcellulose and xylan makes it superior to other known cellulolytic bacteria. Ochrobactrum oryzae BMP03 strain showed laccase activity, which indicates its ability to depolymerize lignin. Lignocellulose-degrading bacteria play a vital role in the biological conversion of lignocellulose biomass to biofuel. Overall, this study shows that termite's gut microbiomes are potential sources of lignocellulose-degrading bacteria that can be cultured and used in the biological conversion of lignocellulose biomass to biofuel.

Reduced graphene oxide and PEG-grafted TEMPO-oxidized cellulose nanocrystal reinforced poly-lactic acid nanocomposite film for biomedical application.

In this work, both cellulose nanocrystals (CNC) and reduced graphene oxide (rGO) were reinforced into poly-lactic acid (PLA) to enhance the stiffness, strength and thermal stability of the pure polymer i.e. PLA. To enhance the uniform dispersion of CNC (which is a major concern with PLA) and rGO in the hydrophobic polymer matrix, CNC's surface was first modified using TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical) oxidation method followed by surface grafting of TEMPO-oxidized CNC (TOCNC) performed with polyethylene glycol (PEG). The PEG-grafting on crystalline region of cellulose nanofibrils was achieved through ionic bonds by applying ion-exchange method (simple and easy method). The obtained PEG-grafted-TOCNC indicated uniform dispersion at the nanoelement level in non-polar (organic) compound i.e. chloroform. Further, the PEG-grafted-TOCNC/chloroform with different blend ratios, PLA/chloroform and rGO/chloroform solution were mixed together and solvent casted onto a petri-dish to obtain PLA/PEG-TOCNC/rGO nanocomposite film. The tensile strength and thermal stability were remarkably improved for the film containing highest wt% of modified CNC. In addition to this, the film showed reduced water vapor barrier properties and antioxidant activity which enables it to be used as a packaging films. Moreover, the film displayed negligible toxicity and cytocompatibility to fibroblast cells C3H10T1/2. These attractive properties of PLA/PEG-TOCNC/rGO nanocomposite film render the application of film as a scaffold in tissue engineering field and in packaging application.