Waste-driven single crystalline sulphur-doped GQDs are synthesized via a green hydrothermal route with the highest quantum yield and excellent biocompatibility for bioimaging.

Nitrogen doped graphene nanosheets (NGS) were synthesized from carbon nanosheets (CNS). The as-synthesized NGS were employed to selectively detect dopamine (DA) and uric acid (UA) with enhanced electrocatalytic activity.

The advent of novel carbonaceous nanomaterials (CMs) associated with microalgae paved an alternate way for the bioeconomic production of biofuels as well as high value added compounds. Herein, we for the first time, present a holistic approach for sustainable biomass and lipid production from Chlorella pyrenoidosa, wherein CMs, namely N-doped carbon nanosheets (CNS) and Ndoped graphene nanosheets (NGS) were used as one of the algal growth supporting factors. Doping carbon nanomaterials with nitrogen can effectively tune its electronic structure and other intrinsic properties for efficient photocatalysis. The utilization of CNS and NGS in this process lead to rapid, environment friendly, and facile assimilation of biomass and lipids for the development of nutraceuticals, pharmaceuticals, and other bioenergy associated applications. Employing a suite of characterization methods, the intrinsic structural and morphological properties of CMs were revealed. Compared with control, the lipid content obtained in the presence of undoped carbonized carbon materials (CCM), CNS, and NGS were found to be around 1.5-, 2-, and 6-fold higher, respectively, at similar growth conditions. We, therefore, envisage that graphitic nitrogen rich NGS plays a pivotal role in enhancing the lipid production from algae. This finding, therefore, exhibits a promising potential to bring about a paradigm shift in the field of bioenergy frameworks.

A variety of pH responsive hydrogels possessing macroporous interiors resembling honey-comb framework with continuous skin on the surface have been developed by free radical aqueous copolymerization of Acrylic acid (AAc) and 2-(Dimethylamino)ethyl methacrylate (DMAEMA) (Poly (AAc-co-DMAEMA) (PAD) hydrogels).This one step polymerization process makes scaling-up easier for mass production. Our formulations, being devoid of any chemical cross-linkers, remained dimensionally stable in buffer solutions of pH 1.2-7.4 with interlocked nanogels being identified as the building blocks of the network structures. Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), uniaxial compression testing and scanning electron microscopy (SEM) were used to characterize the hydrogels (PADs). Compressive elastic modulus and compressive strength of the swollen hydrogels at pH 7 were found to vary with composition from ~3 to ~11 kPa and ~178 to ~206 kPa, respectively. The swollen gels showed fairly strong viscoelastic behaviour and underwent deformation from ~70% to 85% before failure, indicating the formation of robust 3D structures of PADs. Preliminary investigation into the biocompatibility of our hydrogels done by cytotoxicity assays using HeLa and McCoy mouse fibroblast cell lines have revealed that they are non-cytotoxic, paving the way for further biomedical applications. Swelling behaviour and release kinetics of bovine serum albumin (BSA) were investigated in various buffer solutions that mimic the pH-metric hierarchy in gastrointestinal (GI) tract. Equilibrium swelling ratio was found to vary from 171% (mass) to 2027% (mass) depending on the pH and composition of hydrogels. Different compositions of PAD systems were investigated to verify the possibility of tailor-making the drug release behaviour of PAD formations.

Non-covalently functionalized PFNGS, exhibiting exceptional biocompatibility, were employed for sensing nitric oxide with high temporal resolution.

This work reports first electrochemical preparation of exceptionally biocompatible, highly crystalline, and well exfoliated nitrogen doped graphene nanosheets (eNGS) from carbon nanosheets for the development of mighty platforms in the field of modern biosensing and other biological applications for human welfare. eNGS displayed exceptional biocompatibility. Administration of the as-synthesized eNGS to rat models did not lead to any significant deviation or inimical consequences in its functional observation battery (FOB) tests, GSH levels or the histology of the vital organs of the rat models. The pictomicrographs of myocytes nuclei and myofibrillar for heart, hippocampus (CA1) section for brain, central vein, and hepatocytes for liver and parenchyma, tubules and glomeruli for kidney also remained unaffected. Moreover, the resultant nanoelectrocatalyst displayed enhanced electrochemical performance towards real-time sensing of dopamine (DA) from human urine sample in the presence of interferences, such as ascorbic acid (AA) and uric acid (UA).

The rising incidence of drug resistant diseases has led to an increasing need for developing novel and efficient antimicrobial products that can counter these infections. We report for the first time, the exceptional antibacterial activity of N-doped carbon nanosheets (CNS). The antibacterial activity and mechanism of action of CNS was examined for gram negative E. coli. Based on the cell viability tests, nucleic acid quantitation, time and concentration dependent antibacterial activity tests and SEM and TEM micrographs, performed under similar concentration and incubation conditions, the CNS dispersion shows the highest antibacterial activity, sequentially followed by GO, rGO and CCM, with a loss of cell viability by 92.1 AE 1.7%. We envision that the physical stress and piercing action caused by sharp "knifeedges" as well as the presence of heteroatoms in CNS result in the rupturing of the bacterial cell wall, eventually causing cell death. The high I D /I G ratio (0.99) of CNS is closely related to the formation of structural and edge plane defects, especially in the case of N-doped carbonaceous materials, which is one of the key factors in enhancing the antibacterial activity of the material.

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