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New materials' synthesis and utilization have shown many critical challenges in healthcare and other industrial sectors as most of these materials are directly or indirectly developed from fossil fuel resources. Environmental regulations and sustainability concepts have promoted the use of natural compounds with unique structures and properties that can be biodegradable, biocompatible, and eco-friendly. In this context, nanocellulose (NC) utility in different sectors and industries is reported due to their unique properties including biocompatibility and antimicrobial characteristics. The bacterial nanocellulose (BNC)-based materials have been synthesized by bacterial cells and extracted from plant waste materials including pineapple plant waste biomass. These materials have been utilized in the form of nanofibers and nanocrystals. These materials are found to have excellent surface properties, low density, and good transparency, and are rich in hydroxyl groups for their modifications to other useful products. These materials are well utilized in different sectors including biomedical or health care centres, nanocomposite materials, supercapacitors, and polymer matrix production. This review explores different approaches for NC production from pineapple waste residues using biotechnological interventions, approaches for their modification, and wider applications in different sectors. Recent technological developments in NC production by enzymatic treatment are critically discussed. The utilization of pineapple waste-derived NC from a bioeconomic perspective is summarized in the paper. The chemical composition and properties of nanocellulose extracted from pineapple waste may have unique characteristics compared to other sources. Pineapple waste for nanocellulose production aligns with the principles of sustainability, waste reduction, and innovation, making it a promising and novel approach in the field of nanocellulose materials., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The present study reports significant enhancement in the red upconversion emission of Er(3+) in NaSc0.8Er0.02Yb0.18F4 upconversion nanoparticles (UCNPs), via a two step process, (i) codoping of Gd(3+) ion at Sc(3+) site and (ii) attaching gold nanoparticles (AuNPs) at the surface of these codoped nanostructures, and further probes the use of these Gd:UCNPs@AuNPs for bioimaging application. The Gd(3+) codoping tailors the particle size (reduces) of UCNPs and bring out Er(3+)-Yb(3+) ion pair in close proximity, which promotes the cross relaxation mechanism and boosts the population in red emitting level (4)F9/2. Further, attachment of AuNPs on the surface of UCNPs gives 2-fold advantages, that is, reduction in green band (through resonance energy transfer with efficiency 31.54%) and enhancement in red band (through plasmonic effect). It gives red to green (R/G) ratio nearly 20:1 (almost single band red UC), which is quite promising for imaging application. In addition to this, codoping of Gd(3+) enhances the magnetic moment appreciably and the obtained magnetic moment for NaSc0.75Er0.02Yb0.18Gd0.05F4 UCNPs (∼1.7 emu/g) is close to the reported values for bioseparation in case of NPs. This shows the potential of the material for multimodal (optical and magnetic both) imaging application. These magnetoluminescence particles were found safe up to 1 mg/mL dose as assessed by cytotoxicity measurement in human cervical cancer (HeLa) and lung cancer (A549) cells. Ultrafine nanoparticles, transparent, and stable colloidal solution and the unique red UC emission endow these NPs as optical probe for imaging applications.

The increasing utilization of nanoparticles (NPs) in agricultural practices has led to a surge in demand for nano-based products. Herein, we investigate the dose-dependent impacts of nickel hydroxide (Ni(OH)2)/nickel (Ni) NPs, synthesized using Asparagus racemosus Linn. leaf extract, on the seed germination and growth of Vigna radiata (Linn.) Wilczek. In all seed samples, 100% germination was observed in Treatment 1 (2.74 mg mL−1) and Treatment 2 (5.48 mg mL−1) of Ni/Ni(OH)2 NPs. However, in Treatment 3 (8.22 mg mL−1) and Treatment 4 (10.96 mg mL−1), the germination percentage was lower, reaching 80%. Further, Treatment 5 (13.70 mg mL−1) of Ni/Ni(OH)2 NPs showed a reduced germination rate of 60%, indicating a prolonged germination process at higher concentrations. Remarkably, the length of seedlings showed a significant increase in all experimental treatments compared to the control group, which received 5 mL of distilled water. Among the investigated parameters, Treatment 2 demonstrated the most promising outcomes, exhibiting the highest chlorophyll stability index (23.73%) and membrane stability index (67.89%) values, as well as the lowest root ion leakage (24.75%). These findings indicate that Ni/Ni(OH)2 has the capacity to enhance seed germination and foster seedling growth. [ABSTRACT FROM AUTHOR]

We present here the results of structural investigations on magnetoelectric multiferroic (1 -- x) BiFeO3-xCaTiO3 (BF-xCT) solid solution nanoparticles, synthesized by the sol--gel method, using Rietveld analysis on powder x-ray diffraction data in the compositional range of 0 ≤ x ≤ 0.60. The stability of various crystallographic phases in BF-xCT solid solution nanoparticles at room temperature is determined accurately. The structure of BF-xCT solid solution nanoparticles is monoclinic (Cc) for 0.10 ≤ x ≤ 0.22 and orthorhombic (Pbnm) for x ≥ 0.28, whereas the two phases coexist in the morphotropic phase boundary region of 0.23 ≤ x ≤ 0.27 as confirmed by Rietveld analysis. We have established the phase diagram at room temperature for BF-xCT solid solution nanoparticles as a function of composition. Transmission electron microscopy confirmed the morphology, microstructure, and the crystallinity of the nanoparticles, and the average particle size is found to be in the range of 30-50 nm. [ABSTRACT FROM AUTHOR]

The effect of high energy milling on the powder morphology and photoluminescence of Eu (5mol %)-doped YBO 3 phosphor materials was studied. The Eu-doped YBO 3 materials were prepared via conventional solid-state mixing method followed by milling for 30 min and 1 h. The crystallite and particle size of the phase pure Eu-doped YBO 3 powders were found decrease with milling time, as confirmed from Scherrer's formula and electron micrographs, respectively. Rupture of the phosphor powders led to formation of smaller particles, which were also found deposited on the surface of bigger particles during milling. The emission spectra of un-milled and milled samples were excited at 238 nm, 254 nm and 394 nm, and several peaks were observed in the emission spectra in the region from 580 nm to 700 nm, which correspond to the transition of europium ions from 5D 0 →7F J (J = 0, 1, 2, 3, 4) levels. The emission intensity ratio between red and orange (R/O) is greater than unity for all samples when excited at 238 nm, 254 nm and 394 nm, which indicates that the samples are red in color purity. Further, the CIE co-ordinates suggest that all of the samples fall in the reddish region and using 254 nm as an excitation wavelength gives better CIE co-ordinates for all samples. Image 1 • This work explores the effect of milling on morphology and PL of Eu-doped YBO 3. • Crystallite and particle size of Eu-doped YBO 3 decreases with milling time. • Particles get ruptured and shattered to nanoscale range during milling. • Smaller particles with surface disorder due to milling causes an increase of R/O. • Excitation wavelength of 254 nm suggests better CIE and samples are red in color. [ABSTRACT FROM AUTHOR]

A simple green chemistry route has been developed for the synthesis of copper (Cu) quantum dots (QDs) from copper sulfate using leaf extract of Mangifera indica (L.) with assessment of their catalytic, antibacterial and antioxidant activities. The impact of quantities of leaf extract, concentrations of copper sulfate, incubation temperature, pH and reaction time were investigated so as to attain regulation on the QDs particle size and stability. The bio-fabrication of Cu QDs was studied by employing UV–Visible (UV–Vis) spectrophotometry at wavelength (λ max) 338 nm. Fourier-Transform Infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) along with Selected Area Electron Diffraction (SAED) as well as X-Ray Diffractometer (XRD) were employed to characterize the morphology as well as structure of Cu QDs. The FTIR spectra depicted polyphenolic compound 'mangiferin' as major phytochemical from M. indica leaf extract that functioned as reducing, capping and stabilizing agent during Cu QDs fabrication. Highly stable spherical Cu QDs with very narrow size distributions (4–7 nm) have been observed. These Cu QDs revealed distinctive catalytic activity (against the reduction of anthropogenic prominent contaminant methylene blue for environment protection), potent antimicrobial activity (against Escherichia coli KT45/45A and Staphylococcus aureus KT68) and free radical scavenging activity. These studies established that M. indica leaf extract is a cost-effective promising green material for producing Cu QDs with multi-applications as catalyst, antibacterial and antioxidant agents. Image 101680 • Mangifera indica is used to synthesize and stabilize copper quantum dots (Cu QDs). • Cu QDs disintegrate hazardous methylene blue in 195 min. • Cu QDs depict good antibacterial activity against E. coli and S. aureus at 24 h. • Cu QDs exhibit optimal antioxidant activity against 1,1-diphenyl-2-picrylhydrazyl within 30 min. [ABSTRACT FROM AUTHOR]