A critical review on the recent trends of photocatalytic, antibacterial, antioxidant and nanohybrid applications of anatase and rutile TiO2 nanoparticles.

Titanium dioxide nanoparticles (TiO2 NPs) have become a focal point of research due to their widespread daily use and diverse synthesis methods, including physical, chemical, and environmentally sustainable approaches. These nanoparticles possess unique attributes such as size, shape, and surface functionality, making them particularly intriguing for applications in the biomedical field. The continuous exploration of TiO2 NPs is driven by the quest to enhance their multifunctionality, aiming to create next-generation products with superior performance. Recent research efforts have specifically focused on understanding the anatase and rutile phases of TiO2 NPs and evaluating their potential in various domains, including photocatalytic processes, antibacterial properties, antioxidant effects, and nanohybrid applications. The hypothesis guiding this research is that by exploring different synthesis methods, particularly chemical and environmentally friendly approaches, and incorporating doping and co-doping techniques, the properties of TiO2 NPs can be significantly improved for diverse applications. The study employs a comprehensive approach, investigating the effects of nanoparticle size, shape, dose, and exposure time on performance. The synthesis methods considered encompass both conventional chemical processes and environmentally friendly alternatives, with a focus on how doping and co-doping can enhance the properties of TiO2 NPs. The research unveils valuable insights into the distinct phases of TiO2 NPs and their potential across various applications. It sheds light on the improved properties achieved through doping and co-doping, showcasing advancements in photocatalytic processes, antibacterial efficacy, antioxidant capabilities, and nanohybrid applications. The study concludes by emphasizing regulatory aspects and offering suggestions for product enhancement. It provides recommendations for the reliable application of TiO2 NPs, addressing a comprehensive spectrum of critical aspects in TiO2 NP research and application. Overall, this research contributes to the evolving landscape of TiO2 NP utilization, offering valuable insights for the development of innovative and high-performance products.

Improving photocatalytic efficiency of MnFe2O4 ferrites via doping with Zn2+/La3+ ions: photocatalytic dye degradation for water remediation.

The interference of industrial effluents such as dyes, surfactants, metals, polycyclic aromatic hydrocarbons, and pharmaceutical waste has become a severe global problem for human health due to their carcinogenic, mutagenic, and toxic properties. Ferrites were considered promising photocatalysts for the degradation of organic and inorganic dyes. This study mainly focused on improving the photocatalytic performance of MnFe2O4 nanoferrites via doping of Zn2+ and La3+ ions. The zinc and lanthanum substituted Mn1-xZnxLayFe2-yO4 nanoferrites were prepared by the sol-gel auto-combustion technique for the degradation of organic textile malachite green dye (MGD) under the natural solar irradiation. The synthesized nanoferrites were investigated for their structural properties, surface morphology and elemental analysis, optical studies, magnetic properties, and photocatalytic performance by XRD, FESEM/EDX, FTIR/Raman spectrum, vibrating sample magnetometer, and UV-visible spectrophotometer, respectively. The substitution of zinc and lanthanum improved the photocatalytic efficiency of nanoferrites, and about 96% of MGD was degraded by Mn0.97Zn0.03La0.04Fe1.96O4 after 60 min of irradiation. The results showed the pseudo-first-order kinetics for dye degradation using undoped and Zn/La-doped MnFe2O4 photocatalysts.

Nanotechnology for sustainable agro-food systems: The need and role of nanoparticles in protecting plants and improving crop productivity.

The rapid population growth and environmental challenges in agriculture need innovative and sustainable solutions to meet the growing need for food worldwide. Recent nanotechnological advances found its broad applicability in agriculture's protection and post-harvesting. Engineered nanomaterials play a vital role in plant regulation, seed germination, and genetic manipulation. Their size, surface morphology, properties, and composition were designed for controlled release and enhanced properties in agriculture and the food industry. Nanoparticles can potentially be applied for the targeted and controlled delivery of fertilizers, pesticides, herbicides, plant growth regulators, etc. This help to eliminate the use of chemical-based pesticides and their water solubility, protect agrochemicals from breakdown and degradation, improve soil health, and naturally control crop pathogens, weeds, and insects, ultimately leading to enhanced crop growth and production capacity in the food industry. They can be effectively utilized for nano-encapsulation, seed germination, genetic manipulation, etc., for protecting plants and improving crop productivity, safe and improved food quality, and monitoring climate conditions. Nanoparticles played a crucial role in the uptake and translocation processes, genetically modifying the crops, high seed germination, and productivity. In this article, we have reviewed some important applications of nanoparticles for sustainable agro-food systems. The need and role of nanotechnology concerning challenges and problems faced by agriculture and the food industry are critically discussed, along with the limitations and future prospects of nanoparticles.

Carboxymethyl cellulose based sustainable hydrogel for colon-specific delivery of gentamicin.

The current research includes the synthesis, improvement of NaCMC-cl-DMAA/AAc hydrogel and in-situ controlled release of gentamicin within various pH environments. The prepared hydrogel was then modified using boron nitride nanosheets aiming to enhancement in the adsorption rate. The prepared hydrogels were investigated by FTIR, XRD, FESEM, TGA/DSC, swelling and cell viability analysis. Cytotoxicity study indicated that prepared sample has a cytocompatibility nature towards healthy normal human cell line (FR2 cells). By changing the pH environment, the drug release properties of the hydrogels can be controlled. The cumulative rate of release for NaCMC-cl-DMAA/AAc hydrogel was 76.5 % at pH = 2.2 and 87.5 % at pH = 7.4. Whereas drug release rate for NaCMC-cl-DMAA/AAc-BNNSs hydrogel composite was 78.6 % at pH = 2.2 and 97.3 % at pH = 7.4 within 4320 min. Gentamicin release kinetics have been determined using the Korsemeyar-Peppas model, which confirms the drug release mechanism.

Prospects of Biosensors Based on Functionalized and Nanostructured Solitary Materials: Detection of Viral Infections and Other Risks.

Advances in nanotechnology over the past decade have emerged as a substitute for conventional therapies and have facilitated the development of economically viable biosensors. Next-generation biosensors can play a significant role in curbing the spread of various viruses, including HCoV-2, and controlling morbidity and mortality. Pertaining to the impact of the current pandemic, there is a need for point-of-care biosensor-based testing as a detection method to accelerate the detection process. Integrating biosensors with nanostructures could be a substitute for ultrasensitive label-free biosensors to amplify sensing and miniaturization. Notably, next-generation biosensors could expedite the detection process. An elaborate description of various types of functionalized nanomaterials and their synthetic aspects is presented. The utility of the functionalized nanostructured materials for fabricating nanobiosensors to detect several types of viral infections is described in this review. This review also discusses the choice of appropriate nanomaterials, as well as challenges and opportunities in the field of nanobiosensors.

Robust and sustainable Mg1-xCexNiyFe2-yO4 magnetic nanophotocatalysts with improved photocatalytic performance towards photodegradation of crystal violet and rhodamine B pollutants.

This study aims at manufacturing Ce3+/Ni2+ ions doped Mg nanoferrites by the sol-gel method for the photocatalytic degradation of rhodamine B and crystal violet pollutants under visible natural sunlight. The particle size of synthesized nanoferrites was calculated through XRD, Hall-William plots, and TEM analysis, which perfectly agree with each other. FTIR study investigated the existence of stretching vibrations in M - O (metal-oxygen) complexes at the tetrahedral (A-site) and octahedral sites (B-site). The Raman spectra of synthesized nanophotocatalysts show the presence of four vibrational modes (Eg + 2T2g + A1g), providing suitable information of occupancy of Mg2+, Ce3+, Ni2+, and Fe3+ ions at the interstitial sites of undoped and Ce3+/Ni2+ doped MgFe2O4 crystal structure. The synthesized MGF3 nanophotocatalyst performs well with degradation of 97.674% crystal violet (CV) and 90.05% rhodamine B (RhB) under natural sunlight in 60 min. The experimental results showed that doped MgFe2O4 nanoferrites have a high tendency to photodegrade the RhB and CV dyes in an aqueous form. The pseudo-first-order equation reflects the best photocatalytic process kinetics and studied the feasibility of RhB and CV dyes adsorption on the doped and undoped MgFe2O4 nanoferrites. The results show good support for adsorption by the spontaneous photodegradation process. The excellent photocatalytic activity of synthesized nanoferrites under natural sunlight verifies them as a potential candidate for the photodegradation of organic dyes. Finally, the antibacterial activity of magnetic nanoferrites was examined against S. aureus and E. Coli. The studies demonstrated that synthesized magnetic nanoferrites were more effective against S. aureus.

Fabrication and characterization of chitosan-crosslinked-poly(alginic acid) nanohydrogel for adsorptive removal of Cr(VI) metal ion from aqueous medium.

In this study, chitosan-crosslinked-poly (alginic acid) nanohydrogel (CN-cl-PL(AA)NHG) was synthesized by co-polymerization method. It was used an effective adsorbent for the exclusion of Cr(VI) metal ion from aqueous medium. The synthesized nanohydrogel was characterized by FTIR, SEM and TEM. The TEM images clearly indicated the appearance of smooth surface with average size of particles ranging from 30 to 80nm. The effect of different adsorption parameters like agitation time, temperature, initial metal ion concentration and adsorbent dosage was studied and optimized. The results demonstrated that the prepared chitosan-crosslinked-poly (alginic acid) nanohydrogel had high adsorption tendency for the removal of Cr(VI) from the aqueous solution. The pseudo-second-order equation represented the better adsorption kinetics for the adsorption process. The thermodynamic studies showed the adsorption of Cr(VI) onto CN-cl-PL(AA)NHG was spontaneous and chemical in nature.

Eicosyl ammoniums elicited thermal reduction alleyway towards gold nanoparticles and their chemo-sensor aptitude.

The construction of dimethylenebis(eicosyldimethylammonium bromide) surfactant-directed gold nanoparticles (NPs) has been accomplished via a one-pot thermal reduction of HAuCl4 with trisodium citrate. The effect of cationic twin-tail surfactants, dimethylenebis(hexadecyldimethylammonium bromide) (16-2-16), dimethylenebis(octadecyldimethylammonium bromide) (18-2-18) and dimethylenebis(eicosyldimethylammonium bromide) (20-2-20), and their concentrations on shape and size of Au nanoparticles was thoroughly investigated. The UV-Vis spectroscopy and transmission electron microscopy (TEM) results show that longer tail length surfactants act as shape-directing agents promoting diversified morphologies. The formation of multiple-shaped Au nanoparticles, such as round, hexagonal, pentagonal, triangular and rod-like, has been confirmed from microstructure analysis; among them, many triangular shapes enhanced at elevated levels of surfactant concentration. In addition, the triangular Au nanoparticles with truncated corners were changed to smooth corners as the hydrocarbon chain length increased from (18-2-18) to (20-2-20). The concentration and hydrocarbon tails of twin-tail surfactants strongly influence the size and structure of Au NPs. In addition, the Au NPs synthesized with the twin-tail surfactant (18-2-18) were found to be highly sensitive towards Hg(2+), which could be because of the preferential adsorption of Hg(0) on the lower energy facets of triangular-shaped Au NPs.

Biodegradable and conducting hydrogels based on Guar gum polysaccharide for antibacterial and dye removal applications.

Conducting hydrogels possessing antibacterial activity were developed using a two-step free-radical aqueous polymerization method to incorporate polyaniline chains into an adsorbent Guar gum/acrylic acid hydrogel network. The material properties of the synthesized samples were characterized using FTIR spectroscopy, thermal analysis and scanning electron microscopy techniques. Conducting hydrogels were tested for antibacterial activities against gram-positive Staphylococcus aureus and gram-negative Escherichia coli bacteria and demonstrated antibacterial activity. Synthesized hydrogel samples can be potential adsorbent materials for dye removal applications.

Guar gum based biodegradable, antibacterial and electrically conductive hydrogels.

Guar gum-polyacrylic acid-polyaniline based biodegradable electrically conductive interpenetrating network (IPN) structures were prepared through a two-step aqueous polymerization. Hexamine and ammonium persulfate (APS) were used as a cross linker-initiator system to crosslink the poly(AA) chains on Guar gum (Ggum) backbone. Optimum reaction conditions for maximum percentage swelling (7470.23%) were time (min) = 60; vacuum (mmHg) = 450; pH = 7.0; solvent (mL) = 27.5; [APS] (mol L(-1)) = 0.306 × 10(-1); [AA] (mol L(-1)) = 0.291 × 10(-3) and [hexamine] (mol L(-1))=0.356 × 10(-1). The semi-interpenetrating networks (semi-IPNs) were converted into IPNs through impregnation of polyaniline chains under acidic and neutral conditions. Fourier transform infra-red spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) techniques were used to characterize the semi-IPNs and IPNs. Synthesized semi-IPNs and IPNs were further evaluated for moisture retention in different soils, antibacterial and biodegradation behavior.