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Pathogenic bacteria and their metabolites are the leading risk factor in food safety and are one of the major threats to human health because of the capability of triggering diseases with high morbidity and mortality. Nano-optical sensors for bacteria sensing have been greatly explored with the emergence of nanotechnology and artificial intelligence. In addition, with the rapid development of cross fusion technology, other technologies integrated nano-optical sensors show great potential in bacterial and their metabolites sensing. This review focus on nano-optical strategies for bacteria and their metabolites sensing in the field of food safety; based on surface-enhanced Raman scattering (SERS), fluorescence, and colorimetric biosensors, and their integration with the microfluidic platform, electrochemical platform, and nucleic acid amplification platform in the recent three years. Compared with the traditional techniques, nano optical-based sensors have greatly improved the sensitivity with reduced detection time and cost. However, challenges remain for the simple fabrication of biosensors and their practical application in complex matrices. Thus, bringing out improvements or novelty in the pretreatment methods will be a trend in the upcoming future. [ABSTRACT FROM AUTHOR]

Noble bimetallic and trimetallic nanoparticles (NBT-NPs) have superior biomedical applications as compared to their monometallic counterparts. The performance of these nanomaterials depends on their composition, shape and size. Hence, the controlled-synthesis of these nanomaterials is a hot area of research. Till date, no review article in the literature accounts regarding the controlled-synthesis and biomedical applications related to morphology, optimum composition, biocompatibility and versatile chemistry of NBT-NPs. Taking this into contemplation, an effort was made to provide a clear insight into the morphology-controlled synthesis and size/shape-dependent anticancer and bactericidal applications of NBT-NPs. Chemical reduction method for the controlled-synthesis of NBT-NPs is reviewed critically. Furthermore, the potential role of various reaction parameters such as time, reducing agents, stabilizing/capping agents, nature/concentration of precursors, temperature and pH in the shape/size-controlled synthesis of these nanomaterials are discussed. In the second part of this article, anticancer and bactericidal applications of the NBT-NPs are reviewed and the influences of optimum composition, size, surface structure, versatile chemistry and synergism are studied. Finally, the current challenges in the controlled-synthesis and biomedical applications of these nanomaterials, and prospects to resolve related issues are discussed. Chemical reduction method for the synthesis of NBT-NPs is reviewed. The influences of parameters on the control synthesis of NBT-NPs are discussed. Antibacterial and anticancer applications and cytotoxicity of NBT-NPs are reviewed. Possible solutions for the key challenges are discussed. Outlooks about the synthesis and biomedical applications of NBT-NPs are discussed. [ABSTRACT FROM AUTHOR]

In this work, a simple sol–gel method was developed to incorporate Co3O4 into glass waste-derived SiO2 to generate a heterostructured SiO2@Co3O4 nanocomposite. Morphological analysis revealed the presence of tiny Co3O4 grains embedded on to the surface of the spherically shaped SiO2 particles. The SiO2@Co3O4 hetrostructure anode exhibited a reversible capacity as high as 684 mA h g−1 at 0.5 C. Even after 50 cycles, the anode material showed a remarkable Coulombic efficiency of 99% with capacity retention as high as 75% (507 mA h g−1). The synergistic contribution resulting from the alloying/conversion mechanisms associated with the SiO2@Co3O4 resulted in enhanced electrochemical performance. Highlights: The SiO2@Co3O4 composite was generated by a simple sol–gel method using laboratory glass wastes. The SiO2@Co3O4 anode delivered initial-discharge capacity of 1651 mA h g−1. The synergistic effects of SiO2/Co3O4 resulted in a remarkable Columbic efficiency of almost 100%. [ABSTRACT FROM AUTHOR]

Abstract: We report here synthesis of nanostructured MnO2 by using carbon‐quantum dot (CQD) as reducing agent which is obtained by environmentally benign approach from waste material. The obtained carbon quantum dot‐MnO2 nanohybrid is characterized by various analytical techniques. The spectral studies reveal the characteristic absorption/emission features of nanostructured CQD‐MnO2. The X‐ray‐diffraction and microscopic analysis indicate that the synthesized CQD‐MnO2 is crystalline in nature with the grain size in the range of 250 − 300 nm. Electrochemical studies reveals that the carbon quantum dot‐MnO2 nanohybrid electrode exhibits a high specific capacitance of 189 F g‐1 at 0.14 A g‐1 with an excellent stability over 1200 charge‐discharge cycles. The excellent electrochemical performance is attributed to the large surface area and high conductivity due to the presence of conductive nanonetwork of the CQD in the carbon quantum dot‐MnO2 matrix. The symmetric supercapacitor (CQD‐MnO2|Na2SO4|CQD‐MnO2) constructed using the carbon quantum dot‐MnO2 electrodes delivers high energy and power densities with a wide operating potential window of 0 ‐ 1.6 V. [ABSTRACT FROM AUTHOR]