Development of folate-conjugated polypyrrole nanoparticles incorporated with nitrogen-doped carbon quantum dots for targeted bioimaging and photothermal therapy.

PPy nanoparticles are widely employed as PTT agents, because of their exceptional near-infrared absorption properties. Nonetheless, the efficacy of PTT with PPy nanoparticles is hindered by a challenge, specifically, a lack of precise targeting. In this study, a PTT imaging agent was developed by combining NCQDs having bright green fluorescent properties with PPy nanoparticles along with the masking of folic acid to overcome the challenge of targeting. The synthesized PPy:NCQDs:FA nanocomposite, characterized by extraordinary photothermal property, was utilized for imaging of folate receptor positive (FA+) MCF-7 cancer cells through the emission of green fluorescence by NCQDs incorporated within the nanocomposite. Additionally, these nanoparticles demonstrated a good level of cell viability, exceeding 82 %, even at a concentration of 600 µg mL-1. Even the in vivo toxicity inspection of the nanocomposite exemplified no observed acute toxicity at experimental dosages of 1 and 3 mg per kg body weight. By subjecting MCF-7 cells, inoculated with 100 µg mL-1 of nanocomposite, to NIR laser irradiation for 5 min, a significant decline in cell viability was witnessed, establishing the photothermal therapeutic potency of the nanocomposite. The death of cancer cells induced by nanocomposite was verified through MTT assay, imaging of cells by NCQDs alone, with nanocomposite, and by live/dead cell Calcein AM/PI staining assay. Quantification of induced apoptosis post-laser treatment is conducted through staining with Annexin V-FITC/PI. These findings establish potential use of PPy:NCQDs:FA nanocomposite as versatile theranostic agents, capable of targeted bioimaging and treatment for cancer cells exhibiting folate receptors.

Enhancing milk quality assessment with watermelon (Citrullus lanatus) urease immobilized on VS2-chitosan nanocomposite beads using response surface methodology.

An eco-friendly hydrothermal method synthesized VS2 nanosheets. Several spectroscopic and microscopic approaches (TEM) were used to characterize the produced VS2 nanosheet microstructure. VS2, Chitosan, and nanocomposite were used to immobilize watermelon (Citrullus lanatus) urease. Optimization using the Response Surface Methodology and the Box-Behnken design yielded immobilization efficiencies of 65.23 %, 72.52 %, and 87.68 % for chitosan, VS2, and nanocomposite, respectively. The analysis of variance confirmed the mathematical model's validity, enabling additional research. AFM, SEM, FTIR, Fluorescence microscopy, and Cary Eclipse Fluorescence Spectrometer showed urease conjugation to the matrix. During and after immobilization, FTIR spectra showed a dynamic connectivity of chemical processes and bonding. The nanocomposite outperformed VS2 and chitosan in pH and temperature. Chitosan and VS2-immobilized urease were more thermally stable than soluble urease, but the nanocomposite-urease system was even more resilient. The nanocomposite retained 60 % of its residual activity after three months of storage. It retains 91.8 % of its initial activity after 12 reuse cycles. Nanocomposite-immobilized urease measured milk urea at 23.62 mg/dl. This result was compared favorably to the gold standard p-dimethylaminobenzaldehyde spectrophotometric result of 20 mg/dl. The linear range is 5 to 70 mg/dl, with a LOD of 1.07 (±0.05) mg/dl and SD of less than 5 %. The nanocomposite's ksel coefficient for interferents was exceptionally low (ksel < 0.07), indicating urea detection sensitivity. Watermelon urease is suitable for dairy sector applications due to its availability, immobilization on nanocomposite, and reuse.

Biotene: Earth-Abundant 2D Material as Sustainable Anode for Li/Na-Ion Battery.

Natural ores are abundant, cost-effective, and environmentally friendly. Ultrathin (2D) layers of a naturally abundant van der Waals mineral, Biotite, have been prepared in bulk via exfoliation. We report here that this 2D Biotene material has shown extraordinary Li-Na-ion battery anode properties with ultralong cycling stability. Biotene shows 302 and 141 mAh g-1 first cycle-specific charge capacity for Li- and Na-ion battery applications with ∼90% initial Coulombic efficiency. The electrode exhibits significantly extended cycling stability with ∼75% capacity retention after 4000 cycles even at higher current densities (500-2000 mA g-1). Further, density functional theory studies show the possible Li intercalation mechanism between the 2D Biotene layers. Our work brings new directions toward designing the next generation of metal-ion battery anodes.

Immobilization of α-amylase onto functionalized molybdenum diselenide nanoflowers (MoSe2-NFs) as scaffolds: Characterization, kinetics, and potential applications in starch-based industries.

The current study presents the application of molybdenum diselenide nanoflowers (MoSe2-NFs) as an innovative substrate for immobilizing α-amylase by glutaraldehyde activation. This approach results in the development of a nanobiocatalyst that exhibits remarkable advantages compared to a standalone enzyme. Several physical methods, such as fluorescence microscopy, FT-IR, SEM, TEM, XRD, AFM, and Raman spectroscopy, were used to confirm that α-amylase was successfully attached to MoSe2-NFs. By employing the Box-Behnken design of the RSM, the parameters were optimized, resulting in an immobilization efficiency of roughly 87.33%. The immobilized variant of α-amylase demonstrated superior thermostability, pH stability, reusability, and storage stability in comparison to the soluble enzyme. The catalytic activity of α-amylase was highest when immobilized on MoSe2-NFs at the same pH and temperature as the soluble enzyme. However, there was an expansion in the range of parameters in which this activity was observed. Furthermore, the immobilized enzyme exhibited a retention of nearly 80% residual activity following 12 successive reuses. The immobilized enzyme exhibited around 82% residual activity after being stored for 120 days. It is possible that the immobilization process changed the Michaelis-Menten constant, which means that the substrate could no longer reach certain active sites on the enzyme because it had become longer. The study's findings suggest that the α-amylase-MoSe2-NFs system could be useful in industry because it can work in a wider range of temperature and pH conditions. Furthermore, the intrinsic non-toxic characteristics of the matrix, along with its ability to be kept for prolonged periods and recycled, render nano biocatalysts very well-suited for the effective synthesis of maltose in the food and pharmaceutical industries.

Mechanistic insights on Bi-potentiodynamic control towards atomistic synthesis of electrocatalysts for hydrogen evolution reaction.

Herein, electrochemically assisted dissolution-deposition (EADD) is utilized over a three-electrode assembly to prepare an electrocatalyst for hydrogen evolution reaction (HER). Cyclic voltammetry is performed to yield atomistic loading of platinum (Pt) over SnS2 nanostructures via Pt dissolution from the counter electrode (CE). Astonishingly, the working electrode (WE) swept at 50 mV/s is found to compel Pt CE to experience 1000-3000 mV/s. The effect of different potential scan rates at the WE have provided insight into the change in Pt dissolution and its deposition behaviour over SnS2 in three electrode assembly. However, uncontrolled overpotentials at CE in a three-electrode assembly made Pt dissolution-deposition behavior complex. Here, for the first time, we have demonstrated bi-potentiodynamic control for dissolution deposition of Pt in four-electrode assembly over Nickel (Ni) foam. The dual cyclic voltammetry is applied to achieve better control and efficiency of the EADD process, engendering it as a pragmatically versatile and scalable synthesis technique.

A novel approach for rapid and sensitive detection of Zika virus utilizing silver nanoislands as SERS platform.

To control the spread of the disease, the Zika virus (ZIKV), a flavivirus infection spread by mosquitoes and common in across the world, needs to be accurately and promptly diagnosed. This endeavour gets challenging when early-stage illnesses have low viral loads. As a result, we have created a biosensor based on surface-enhanced Raman scattering (SERS) for the quick, accurate, and timely diagnosis of the Zika virus. In this study, a glass coverslip was coated with silver nanoislands, which were then utilized as the surface for creating the sensing platform. Silver nanoislands exhibit strong plasmonic activity and good conductive characteristics. It enhances the Raman signals as a result and gives the SERS platform an appropriate surface. The created platform has been applied to Zika virus detection. With a limit of detection (LOD) of 0.11 ng/mL, the constructed sensor exhibits a linear range from 5 ng/mL to 1000 ng/mL. Hence, even at the nanogram scale, this technique may be a major improvement over clinical diagnosis approaches for making proper, precise, and accurate Zika virus detection.

Atomistic nonlinear carrier dynamics in Ge.

An atomistic technique to successfully demonstrate the ultrafast carrier dynamics in Ge photoconductive samples is reported here. The technique is validated against the experimental findings and with the Drude conductivities. The impact of the various different scattering mechanisms is used to calibrate the experimental results. It is observed that the total scattering rate is not a constant parameter as contrast to Drude model which uses constant scattering rate as the fitting parameter to demonstrate the ultrafast carrier dynamics, but strongly dependent on the applied peak THz field strength. It also contradicts with the relaxation time approximation (RTA) method which uses scattering rate chosen on the empirical basis as the fitting parameter to demonstrate the ultrafast carrier dynamics. On the other hand the limitations and challenges offered by various types of density functional theories (DFT) pose lot of challenges. In current manuscript various types of scattering mechanisms i.e. acoustic, intervalley, Coulomb and impact ionization on the behavior of carrier conductivity are studied in details. The proposed technique has shown capability to extract low and high frequency conductivities accurately which is impossible through the Drude model or DFT based theories. It is observed that the free carrier absorption coefficient depends on the refractive index of the material at low THz frequencies. The solution of Boltzmann transport equation through Monte Carlo technique provides valuable insights for better understanding of ultrafast carrier transportation mechanism. The free carrier absorption spectra are found to be in good agreement with the experimental results at various THz field strengths.

Virulence and pathogenicity determinants in whole genome sequence of Fusarium udum causing wilt of pigeon pea.

The present study deals with whole genome analysis of Fusarium udum, a wilt causing pathogen of pigeon pea. The de novo assembly identified a total of 16,179 protein-coding genes, of which 11,892 genes (73.50%) were annotated using BlastP and 8,928 genes (55.18%) from KOG annotation. In addition, 5,134 unique InterPro domains were detected in the annotated genes. Apart from this, we also analyzed genome sequence for key pathogenic genes involved in virulence, and identified 1,060 genes (6.55%) as virulence genes as per the PHI-BASE database. The secretome profiling of these virulence genes indicated the presence of 1,439 secretory proteins. Of those, an annotation of 506 predicted secretory proteins through CAZyme database indicated maximum abundance of Glycosyl hydrolase (GH, 45%) family proteins followed by auxiliary activity (AA) family proteins. Interestingly, the presence of effectors for cell wall degradation, pectin degradation, and host cell death was found. The genome comprised approximately 895,132 bp of repetitive elements, which includes 128 long terminal repeats (LTRs), and 4,921 simple sequence repeats (SSRs) of 80,875 bp length. The comparative mining of effector genes among different Fusarium species revealed five common and two specific effectors in F. udum that are related to host cell death. Furthermore, wet lab experiment validated the presence of effector genes like SIX (for Secreted in Xylem). We conclude that deciphering the whole genome of F. udum would be instrumental in understanding evolution, virulence determinants, host-pathogen interaction, possible control strategies, ecological behavior, and many other complexities of the pathogen.

Silica Nanospheres Coated Silver Islands as an Effective Opto-Plasmonic SERS Active Platform for Rapid and Sensitive Detection of Prostate Cancer Biomarkers.

The in vitro diagnostics of cancer are not represented well yet, but the need for early-stage detection is undeniable. In recent decades, surface-enhanced Raman spectroscopy (SERS) has emerged as an efficient, adaptable, and unique technique for the detection of cancer molecules in their early stages. Herein, we demonstrate an opto-plasmonic hybrid structure for sensitive detection of the prostate cancer biomarker sarcosine using silica nanospheres coated silver nano-islands as a facile and efficient SERS active substrate. The SERS active platform has been developed via thin (5-15 nm) deposition of silver islands using a simple and cost-effective Radio Frequency (RF) sputtering technique followed by the synthesis and decoration of silica nanospheres (~500 nm) synthesized via Stober's method. It is anticipated that the coupling of Whispering Gallery Modes and photonic nano-jets in SiO2 nanospheres induce Localized Surface Plasmon Resonance (LSPR) in Ag nano-islands, which is responsible for the SERS enhancement. The as-fabricated SERS active platform shows a linear response in the physiological range (10 nM to 100 µM) and an extremely low limit of detection (LOD) of 1.76 nM with a correlation coefficient of 0.98 and enhancement factor ~2 × 107. The findings suggest that our fabricated SERS platform could be potentially used for the rapid detection of bio-chemical traces with high sensitivity.

The Role of GCN2 Kinase in Mediating the Effects of Amino Acids on Longevity and Feeding Behaviour in Drosophila.

Restriction of amino acids in the diet can extend lifespan in diverse species ranging from flies to mammals. However, the role of individual amino acids and the underlying molecular mechanisms are only partially understood. The evolutionarily conserved serine/threonine kinase General Control Nonderepressible 2 (GCN2) is a key sensor of amino acid deficiency and has been implicated in the response of lifespan to dietary restriction (DR). Here, we generated a novel Drosophila GCN2 null mutant and analyzed its response to individual amino acid deficiency. We show that GCN2 function is essential for fly development, longevity and feeding behaviour under long-term, but not short-term, deprivation of all individual essential amino acids (EAAs) except for methionine. GCN2 mutants were longer-lived than control flies and showed normal feeding behaviour under methionine restriction. Thus, in flies at least two systems regulate these responses to amino acid deprivation. Methionine deprivation acts via a GCN2-independent mechanism, while all other EAA are sensed by GCN2. Combined deficiency of methionine and a second EAA blocked the response of GCN2 mutants to methionine, suggesting that these two pathways are interconnected. Wild type flies showed a short-term rejection of food lacking individual EAA, followed by a long-term compensatory increase in food uptake. GCN2 mutants also showed a short-term rejection of food deprived of individual EAA, but were unable to mount the compensatory long-term increase in food uptake. Over-expression of the downstream transcription factor ATF4 partially rescued the response of feeding behaviour in GCN2 mutants to amino acid deficiency. Phenotypes of GCN2 mutants induced by leucine and tryptophan, but not isoleucine, deficiency were partially rescued by ATF4 over-expression. The exact function of GCN2 as an amino acid sensor in vivo and the downstream action of its transcription factor effector ATF4 are thus context-specific with respect to the EAA involved.

SERS based rapid and ultrasensitive detection of Japanese Encephalitis Virus.

Japanese encephalitis (JE) is a mosquito-borne flavivirus infection named Japanese Encephalitis Virus (JEV), prevalent in Asia-pacific countries, requires an accurate and rapid diagnosis to contain the outbreak of the disease. In cases of low viral load in early-stage infections, this task becomes difficult. Therefore, we have developed a surface-enhanced Raman spectroscopy (SERS) based biosensor for rapid, sensitive, and early-stage detection of JE antigen. In this work, silver nanoparticles were deposited over a glass coverslip and used as a substrate for designing the sensing platform. Silver Nanoparticles have good metallic properties and plasmon activity. Therefore, it amplifies the Raman signals and provides a suitable surface for the SERS substrate. The developed platform has been used for the detection of the Japanese encephalitis virus (JEV). The fabricated sensor shows a linear response from 5 ng/mL to 80 ng/mL with a limit of detection (LoD) of ∼7.6 ng/mL. Therefore, this method could be a significant addition to the diagnostic modalities for early, sensitive, and specific diagnoses of JE antigen even at the nanogram level.

Design of an efficient, tunable and scalable freestanding flexible membrane for filter application.

To address the global challenge of water pollution, membrane-based technologies are being used as a dignified separation technology. However, designing low-cost, reusable, freestanding and flexible membranes for wastewater treatment with tunable pore size, good mechanical strength, and high separation efficiency is still a major challenge. Herein, we report the development of a scalable, reusable, freestanding, flexible and functionalized multiwalled carbon nanotube (FMWCNT) membrane filter with tunable pore size for wastewater treatment, which has attractive attributes such as high separation efficiency (>99% for organic dyes and ∼80% for salts), permeance (∼225 L h-1 m-2 bar-1), tensile strength (∼6 MPa), and reusability of both the membrane as well as contaminants separately. This FMWCNTs membrane filter has been developed by a simple vacuum-assisted filtration technique followed by the synthesis of MWCNTs using a cost-effective spray pyrolysis assisted chemical vapor deposition (CVD) technique and chemical functionalization. This study deals with understanding the rejection, retrieval, and reusability of both the membranes as well as waterborne contaminants separately. The developed membrane filter has potential utility in many applications such as wastewater treatment, food industry, and life sciences due to its robust mechanical and separation performance characteristics.

In Situ Fabrication of Activated Carbon from a Bio-Waste Desmostachya bipinnata for the Improved Supercapacitor Performance.

Herein, we demonstrate the fabrication of highly capacitive activated carbon (AC) using a bio-waste Kusha grass (Desmostachya bipinnata), by employing a chemical process followed by activation through KOH. The as-synthesized few-layered activated carbon has been confirmed through X-ray powder diffraction, transmission electron microscopy, and Raman spectroscopy techniques. The chemical environment of the as-prepared sample has been accessed through FTIR and UV-visible spectroscopy. The surface area and porosity of the as-synthesized material have been accessed through the Brunauer-Emmett-Teller method. All the electrochemical measurements have been performed through cyclic voltammetry and galvanometric charging/discharging (GCD) method, but primarily, we focus on GCD due to the accuracy of the technique. Moreover, the as-synthesized AC material shows a maximum specific capacitance as 218 F g-1 in the potential window ranging from - 0.35 to + 0.45 V. Also, the AC exhibits an excellent energy density of ~ 19.3 Wh kg-1 and power density of ~ 277.92 W kg-1, respectively, in the same operating potential window. It has also shown very good capacitance retention capability even after 5000th cycles. The fabricated supercapacitor shows a good energy density and power density, respectively, and good retention in capacitance at remarkably higher charging/discharging rates with excellent cycling stability. Henceforth, bio-waste Kusha grass-derived activated carbon (DP-AC) shows good promise and can be applied in supercapacitor applications due to its outstanding electrochemical properties. Herein, we envision that our results illustrate a simple and innovative approach to synthesize a bio-waste Kusha grass-derived activated carbon (DP-AC) as an emerging supercapacitor electrode material and widen its practical application in electrochemical energy storage fields.

Analysis of Biosynthetic Gene Clusters, Secretory, and Antimicrobial Peptides Reveals Environmental Suitability of Exiguobacterium profundum PHM11.

Halotolerant bacteria produce a wide range of bioactive compounds with important applications in agriculture for abiotic stress amelioration and plant growth promotion. In the present study, 17 biosynthetic gene clusters (BGCs) were identified in Exiguobacterium profundum PHM11 belonging to saccharides, desmotamide, pseudaminic acid, dipeptide aldehydes, and terpene biosynthetic pathways representing approximately one-sixth of genomes. The terpene biosynthetic pathway was conserved in Exiguobacterium spp. while the E. profundum PHM11 genome confirms the presence of the 1-deoxy-d-xylulose 5-phosphate (DXP) pathway for the isopentenyl diphosphate (IPP) synthesis. Further, 2,877 signal peptides (SPs) were identified using the PrediSi server, out of which 592 proteins were prophesied for the secretion having a transmembrane helix (TMH). In addition, antimicrobial peptides (AMPs) were also identified using BAGEL4. The transcriptome analysis of PHM11 under salt stress reveals the differential expression of putative secretion and transporter genes having SPs and TMH. Priming of the rice, wheat and maize seeds with PHM11 under salt stress led to improvement in the root length, root diameters, surface area, number of links and forks, and shoot length. The study shows that the presence of BGCs, SPs, and secretion proteins constituting TMH and AMPs provides superior competitiveness in the environment and make E. profundum PHM11 a suitable candidate for plant growth promotion under salt stress.

Pan-genome analysis of Exiguobacterium reveals species delineation and genomic similarity with Exiguobacterium profundum PHM 11.

The stint of the bacterial species is convoluting, but the new algorithms to calculate genome-to-genome distance (GGD) and DNA-DNA hybridization (DDH) for comparative genome analysis have rejuvenated the exploration of species and sub-species characterization. The present study reports the first whole genome sequence of Exiguobacterium profundum PHM11. PHM11 genome consist of ~ 2.92 Mb comprising 48 contigs, 47.93% G + C content. Functional annotations revealed a total of 3033 protein coding genes and 33 non-protein coding genes. Out of these, only 2316 could be characterized and others reported as hypothetical proteins. The comparative analysis of predicted proteome of PHM11 with five other Exiguobacterium sp. identified 3806 clusters, out of which the PHM11 shared a total of 2723 clusters having 1664 common clusters, 131 singletons and 928 distributed between five species. The pan-genome analysis of 70 different genomic sequences of Exigubacterium strains devoid of a species taxon was done on the basis of GGD and the DDH which identified eight genomes analogous to the PHM11 at species level and may be characterized as E. profundum. The ANI value and phylogenetic tree analysis also support the same. The results regarding pan-genome analysis provide a convincing insight for delineation of these eight strains to species.

Substrate free ultrasonic-assisted hydrothermal growth of ZnO nanoflowers at low temperature.

ZnO nanoflowers (NFs) have been synthesised using a simple cost effective ultrasonic-assisted hydrothermal method at low temperature of 95 °C. Here the NFs consist of petal-like arrangement of several hexagonal-shaped nanorods, the length and diameter of which lie in a range of 100-150 nm and 30-70 nm, respectively. ZnO NFs possess hexagonal wurtzite phase, high crystallinity and strong absorption in the UV region. The optical band gap 3.25 eV of these NFs estimated by two different ways is found to be nearly the same. Room temperature photoluminescence spectrum reveals that the ZnO NFs exhibit dominant UV emission and three major emissions in the visible i.e. violet, blue-green and yellow. NFs are promising nanostructures for application in environment related sensors and antimicrobial activity.

Study on the Growth Parameters and the Electrical and Optical Behaviors of 2D Tungsten Disulfide.

Transition-metal dichalcogenides (TMDCs) with atomic thickness are promising materials for next-generation electronic and optoelectronic devices. Herein, we report uniform growth of triangular-shaped (∼40 µm) monolayer WS2 using the atmospheric-pressure chemical vapor deposition (APCVD) technique in a hydrogen-free environment. We have studied the optical and electrical behaviors of as-grown WS2 samples. The absorption spectrum of monolayer WS2 shows two intense excitonic absorption peaks, namely, A (∼630 nm) and B (∼530 nm), due to the direct gap transitions at the K point. Photoluminescence (PL) and fluorescence studies reveal that under the exposure of green light, monolayer WS2 gives very strong red emission at ∼663 nm. This corresponds to the direct band gap and strong excitonic effect in monolayer WS2. Furthermore, the efficacy of the synthesized WS2 crystals for electronic devices is also checked by fabricating field-effect transistors (FETs). FET devices exhibit an electron mobility of µ ∼ 6 cm2 V-1 s-1, current ON/OFF ratio of ∼106, and subthreshold swing (SS) of ∼641 mV decade-1, which are comparable to those of the exfoliated monolayer WS2 FETs. These findings suggest that our APCVD-grown WS2 has the potential to be used for next-generation nanoelectronic and optoelectronic applications.

Metagenome dataset of wheat rhizosphere from Ghazipur region of Eastern Uttar Pradesh.

Wheat is the major crop in India and like other crops also subjected to influence by microbial communities of the rhizospheric region which are extremely diverse and undoubtedly play a central role in the nutrient cycle, plant productivity and growth promotion. In order to know how changes in the rhizospheric microbial community can make an impact on overall crop function, wheat rhizospheric soil samples from Ghazipur (25.913824 N 83.529715 E) regions of Eastern Uttar Pradesh (Eastern Indogangatic Plain), were collected and analyzed. Full length 16S rRNA gene amplification sequencing was performed to reveal the bacterial community in wheat rhizosphere. A total of 51,909 read were analyzed, out of that only 44,125 reads were classified and 7784 were unclassified using oxford nanopore sequencing and EPI2ME data analysis platform. MinION oxford nanopore sequencing uncovered that dominant phyla were Proteobacteria (68%), followed by firmicutes (13%), bacteroidetes (3%), actinobacteria (3%) and acidobacteria (3%). The data is available at the NCBI - Sequence Read Archive (SRA) with accession number: SRX5275271.

Nanoparticles decorated carbon nanotubes as novel matrix: A comparative study of influences of immobilization on the catalytic properties of Lensculinarisß-galactosidase (Lcß-gal).

In the present study, Multiwalled carbon nanotubes (MWCNT) decorated with two different nanoparticles namely tungsten disulfide (WS2) and tin oxide (SnO2), nanocomposites (NCs) were synthesized via hydrothermal method. Spectroscopic studies showed that both synthesized NCs possess nearly same functional groups but MWCNT-SnO2 NCs are rich in O-functional group. Microscopic studies revealed that both NCs have different morphological microstructure. Lens culinaris ß-galactosidase (Lcß-gal) was immobilized using glutaraldehyde cross-linker resulted in immobilization efficiency of 91.5% and 88% with MWCNT-WS2 and MWCNT-SnO2 NCs, respectively. Remarkable increase in rate of hydrolysis of whey lactose has been observed with both NCs i.e. Lcß-gal immobilized MWCNT-WS2 hydrolyzes the 97% whey lactose in 1.5 h while MWCNT-SnO2 showed maximum 92% of whey hydrolysis in 2 h at optimum conditions. Both nanobiocatalyst could serve as a promising candidates for dairy industries and would offer a potential platform for enzyme based biosensor fabrication.

Immobilization of fenugreek ß-amylase onto functionalized tungsten disulfide nanoparticles using response surface methodology: Its characterization and interaction with maltose and sucrose.

In this communication, fenugreek ß-amylase was immobilized onto functionalized tungsten disulfide nanoparticles through cross-linker glutaraldehyde and successful immobilization was confirmed by SEM, AFM and FTIR spectroscopy. To make the process economical and efficient, optimization of independent variables was carried out using Box-Behnken design of response surface methodology. Approximately similar predicted (85.6%) and experimental (84.2%) immobilization efficiency revealed that the model is suitable for design of space. Optimum temperature was calculated to be 60 °C. After immobilization, an increased Km (2.12 times) and a decreased Vmax (0.58 times), indicated inaccessibility of active site residues to the substrate. The immobilized enzyme retained 77% relative activity after 10 uses whereas 40% residual activity was obtained after 120 days. An increased half-life with concomitantly decreased kinetic rate constant revealed that the immobilized enzyme is more stable at a higher temperature and the process followed first-order kinetics (R2 > 0.93). The limit of detection for maltose and sucrose fluorescence biosensor was found to be 0.052 and 0.096 mM, respectively. Thermodynamic parameters such as changes in Gibbs free energy (ΔG < 0), enthalpy (ΔH > 0) and entropy (ΔS >0) revealed that the process is spontaneous and endothermic, driven by hydrophobic interactions. Thermo-stability data at higher temperature for the immobilized enzyme makes it a suitable candidate for industrial applications in the production of maltose in food and pharmaceutical industries. Furthermore, fluorescence biosensor could be used to detect and quantify maltose and sucrose to maintain the quality of industrial products.