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L-thyroxine serves as a primary biomarker for diagnosing hypothyroidism and it is also utilized in hormone replacement therapy. Regular assessment of thyroxine levels is crucial for preventing health issues in hypothyroid patients, suggesting the requirement of a facile analytical tool for the detection of L-thyroxine. In this work, a straightforward and efficient synthetic method is introduced for in-situ preparation of Mn 2+ -doped boron quantum dots (Mn 2+ @B-QDs) derived from boron powder through a solvothermal reaction. The introduction of Mn 2+ ion into B-QDs not only enhances fluorescence efficiency but also provides favorable sites within the QDs, expanding their potential applications in analytical chemistry. The blue fluorescent Mn 2+ @B-QDs exhibited excellent performance for the selective recognition of L-thyroxine via a dynamic quenching mechanism. Under ideal conditions, a good linear relation was observed between the fluorescence emission intensity ratio of Mn 2+ @B-QDs and the concentration of L-thyroxine in the range of 0.125-5 μM, with a lower detection limit of 59.86 nM. The Mn 2+ @B-QDs exhibited the negligible cytotoxicity against A549 lung cancer cell lines and demonstrated good biocompatibility toward Saccharomyces cerevisiae cells., 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 © 2024 Elsevier B.V. All rights reserved.)

In this work, Cassia tora (C. tora) have been used as a template to synthesize green fluorescent C. tora molybdenum nanoclusters (C. tora-MoNCs) through a green chemistry approach. These C. tora-MoNCs showed a quantum yield (QY) of 7.72% and exhibited a significant emission peak at 498 nm when excited at 380 nm. The as-prepared C. tora-MoNCs had an average size of 3.48 ± 0.80 nm and showed different surface functionality. The as-synthesized C. tora-MoNCs were successfully identified the hydroxyl radical ( • OH) via a fluorescence quenching mechanism. Also, fluorescence lifetime and Stern-Volmer proved that after the addition of • OH radicals it was quenched the fluorescence intensity via a static quenching mechanism. The limit of detection is 9.13 nM, and this approach was successfully utilized for sensing • OH radicals in water samples with a good recovery rate., Competing Interests: Declarations. Ethical Approval: There are no ethical approvals required for this research work. Consent for Publication: Not Applicable. Competing Interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

A fluorescence "turn-off-on" nanoprobe is designed by using europium-doped strontium molybdate perovskite quantum dots (Eu 3+ :SMO PQDs) for the sequential detection of hypoxanthine (Hx) and Fe 3+ . The Eu 3+ :SMO PQDs were prepared by the sol-gel method using Sr(NO 3 ) 2 , (NH 4 ) 6 Mo 7 O 24 .4H 2 O, and Eu(OCOCH 3 ) 3 as precursors. The green fluorescence of Eu 3+ :SMO PQDs was efficiently reduced (turn-off) in the presence of Hx, then it was restored (turn-on) gradually by introducing Fe 3+ due to the competitive formation of Hx@Fe 3+ , which results to the release of Eu 3+ :SMO PQDs. In addition, the fluorescent probe exhibits excellent selectivity and sensitivity. Under the optimized experimental conditions, linear ranges and detection limits were 0.25-25 μM and 12.30 nM for Hx and 0.025-50 μM and 10.44 nM for Fe 3+ , respectively. Furthermore, the fluorescence method was successfully explored to detect Hx and Fe 3+ in plasma and urine samples., Competing Interests: Declarations. Ethical approval: Plasma samples were collected with informed written consent from the patients by Celix Lab, Surat, Gujrat, India and approved by the Ethics Committee of the Indian Council of Medical Research, India. Consent to participate: Not applicable. Consent to publish: Not applicable. Consent for publication: Not Applicable. Competing interests: The authors declare no competing interests., (© 2025. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

This study describes a new method for synthesizing water-soluble carbon dots (CDs) using "Curcuma longa" (green source) named CL-CDs via a single-step hydrothermal process. The as-synthesized CL-CDs exhibited greenish-yellow fluorescence at 548 nm upon excitation at 440 nm. It shows good water stability and exhibits a quantum yield of 19.4%. The developed probe is utilized for sensing triazophos (TZP) pesticide via a dynamic quenching mechanism, exhibiting favorable linearity ranging from 0.5-500 μM with a limit of detection of 0.0042 μM. The as-prepared CL-CDs probe was sensitive and selective towards TZP. Lastly, the successful application of the CL-CDs-based fluorescent probe in water and rice samples highlights its potential as a reliable and efficient method for the detection of TZP in various real sample matrices. Eventually, bioimaging and biocompatibility aspects of CL-CDs have been assessed on Saccharomyces cerevisiae (yeast) cell and lung cancer (A549) cell lines, respectively., Competing Interests: Declarations. Ethical Approval: There are no ethical approvals required for this research work. Consent for Publication: Not Applicable. Competing Interests: The authors declare no competing interests., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Fluorescent copper nanoclusters (Cu NCs) were synthesized by using Withania somnifera (W. somnifera) plant extract as a biotemplate. Aqueous dispersion of W. somnifera-Cu NCs displays intense emission peak at 458 nm upon excitation at 350 nm. This fluorescence emission was utilized for the detection of two pyrethroid pesticides (cypermethrin and lambda-cyhalothrin) via "turn-off" mechanism. Upon the addition of two pyrethiod pesticides independently, the fluorescence emission of W. somnifera-Cu NCs was gradually decreased with increasing concentrations of both pesticides. It was noticed that the decrease in emission intensity at 458 nm was linearly dependent on the logarithm of both pesticides concentrations in the ranges of 0.01-100 μM and of 0.05-100 μM for cypermethrin and lambda-cyhalothrin, respectively. Consequently, the limits of detection were found to be 27.06 and 23.28 nM for cypermethrin and lambda-cyhalothrin, respectively. The as-fabricated W. somnifera-Cu NCs acted as a facile sensor for the analyses of cypermethrin and lambda-cyhalothrin in vegetables (tomato and bottle gourd), which demonstrates that it could be used as portable sensing platform for assaying of two pyrethroid pesticides in food samples., Competing Interests: Declarations. Ethical Approval: There are no ethical approvals required for this research work. Consent for Publication: Not Applicable. Competing Interests: The authors declare no competing interests., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

In this paper, a single-step synthetic approach is presented for the development of bimetallic molybdenum-copper nanoclusters (Mo-CuNCs), shielded by a small molecule 6-thioguanine (6-TG). The Mo-CuNCs possessed a small size, high fluorescence, stable behavior, and good solubility in water. The 6-TG-Mo-CuNCs exhibit strong blue fluorescence emission at 410 nm after exciting at 330 nm as compared to its monometallic nanoclusters. Utilizing 6-TG-Mo-CuNCs superior biochemical stability, uric acid (UA) can be specifically detected as an oxidative stress biomarker using an inner filter effect mechanism. The probe demonstrated good sensing capability for detecting UA within the range of 0.09-5.00 μM and a detection limit of 0.237 μM. The method feasibility is further validated by quantifying UA in urine and plasma samples., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

In this work, a facile and rapid fluorescence turn-off-on sensing method was developed for the detection of Pb 2+ and metalaxyl fungicide in environmental samples using yellow carbon dots (CDs) from Cordia dichotoma fruits. The prepared C. dichotoma-CDs showed the emission band (𝜆 Em ) at 535 nm under 448 nm of excitation wavelength. The fluorescence intensity of C. dichotoma-CDs quenches by Pb 2+ ion and then restores by metalaxyl fungicide, favoring to develop a fluorescence turn-off-on sensing strategy. The intensity ratios (I 0 /I and I/I 0 ) are linear against Pb 2+ (0.01-50 μM) and metalaxyl fungicide (0.025-10 μM) concentrations, offering the detection limits of 0.0054 and 0.0087 μM for Pb 2+ and metalaxyl fungicide, respectively. Additionally, the potential application of C. dichotoma-CD-based fluorescence turn-off-on sensing approach was effectively demonstrated for Pb 2+ and metalaxyl fungicide assays in real samples, which confirms that C. dichotoma-CDs act as "turn-off-on" fluorescent probe for assaying of Pb 2+ and metalaxyl fungicide, respectively., (© 2024 John Wiley & Sons Ltd.)

In this paper, a new synthetic route is introduced for the synthesis of high-luminescent greenish-yellow fluorescent copper nanoclusters (PVP@A. senna-Cu NCs) using Avaram senna (A. senna) and polyvinylpyrrolidone (PVP) as templates. A. senna plant extract mainly contains variety of phytochemicals including glycosides, sugars, saponins, phenols, and terpenoids that show good pharmacological activities such as anti-inflammatory, antioxidant, and antidiabetic. PVP is a stable and biocompatible polymer that is used as a stabilizing agent for the synthesis of PVP@A. senna-Cu NCs. The size, surface functionality, and element composition of the fabricated Cu NCs were confirmed by various analytical techniques. The as-prepared greenish-yellow fluorescent Cu NCs exhibit significant selectivity towards fipronil, thereby favoring to assay fipronil pesticide with good linearity in the range of 3.0-30 μM with a detection limit of 65.19 nM. More importantly, PVP@A. senna-Cu NCs are successfully applied to assay fipronil in vegetable and grain samples., Competing Interests: Declarations. Ethical Approval: There are no ethical approvals required for this research work. Consent for Publication: Not Applicable. Competing Interests: The authors declare no competing interests., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Water dispersible L-glutamic acid (Glu) functionalized cesium lead bromide perovskite quantum dots (CsPbBr 3 PQDs), namely CsPbBr 3 @Glu PQDs were synthesized and used for the fluorescence "turn-off" detection of myoglobin (Myo). The as-prepared CsPbBr 3 @Glu PQDs exhibited an exceptional photoluminescence quantum yield of 25% and displayed emission peak at 520 nm when excited at 380 nm. Interestingly, the fluorescence "turn-off" analytical approach was designed to detect Myo using CsPbBr 3 @Glu PQDs as a simple optical probe. The developed probe exhibited a wide linear range (0.1-25 µM) and a detection limit of 42.42 nM for Myo sensing. The CsPbBr 3 @Glu PQDs-based optical probe provides high ability to determine Myo in serum and plasma samples., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Designing stimuli-responsive drug delivery vehicles with higher drug loading capacity, sustained and targeted release of anti-cancer drugs and able to mitigate the shortcomings of traditional systems is need of hour. Herein, we designed stimuli-responsive, self-healable, and adhesive hydrogel through synergetic interaction between [Cho][Gly] (Choline-Glycine) and sodium alginate (SA). The hydrogel was formed as a result of non-covalent interaction between the components of the mixture forming the fibre kind morphology; confirmed through FTIR/computational analysis and SEM/AFM images. The hydrogel exhibited excellent mechanical strength, self-healing ability, adhesive character and most importantly; adjustable injectability. In vitro biocompatibility of the hydrogel was tested on HaCaT and MCF-7 cells, showing >92 % cell viability after 48 h. The hemolysis ratio (<4 %) of the hydrogel confirmed the blood compatibility of the hydrogel. When tested for drug-loading capacity, the hydrogel show 1500 times drug loading for the 5-fluorouracil (5-FU) against the SA based hydrogel. In vitro release data indicated that 5-FU have more preference towards the cancerous cell condition, i.e. acidic pH (>85 %), whereas the drug-loaded hydrogel successfully killed the MCF-7 and HeLa cell with a 50 -1.92 mM value. The studied hydrogel paves way towards controlled and sustained delivery of anti-cancer drug for the treatment of breast cancer., 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 © 2024 Elsevier B.V. All rights reserved.)

A hydrothermal synthetic method is established to produce blue fluorescent Eu 3+ -doped niobium carbide MXene quantum dots (Eu 3+ -Nb 2 C MQDs). The synthesized Eu 3+ -Nb 2 C MQDs demonstrated a quantum yield of 20.61% and a maximum emission intensity at 405 nm. The as-prepared Eu 3+ -Nb 2 C MQDs acted as a sensor for the rapid and sensitive detection of hypoxanthine through fluorescence quenching, and of fluoxetine through fluorescence enhancement mechanisms. The emission peak of Eu 3+ -Nb 2 C MQDs at 405 nm exhibited a linear response for hypoxanthine and fluoxetine in the ranges of 0.5-25 µM and 0.125-2.5 µM, with detection limits of 15.0 and 3.7 nM, respectively. The newly developed probe was effectively used for the selective detection of hypoxanthine and fluoxetine in biofluids and pharmaceutical samples. Remarkably, the Eu 3+ -Nb 2 C MQDs exhibited minimal cytotoxicity towards A549 lung cancer cells and showed great potential as imaging agent for imaging of Saccharomyces cerevisiae cells., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

In this study, carbon dots (CDs) were synthesized from Peltophorum pterocarpum flowers as the precursor material using the hydrothermal method. The fluorescence emission spectra of the resulting Peltophorum pterocarpum CDs (PP-CDs) exhibited excitation-independent behavior, showing the fluorescence emission peak at 410 nm when excited at 330 nm. This method is simple, rapid and well consistent with the green chemistry and sustainable analytical method development. The as-synthesized PP-CDs acted as a promising fluorescent probe for detecting carbendazim (CBZ) via aggregation-induced emission mechanism, showing a linear response to CBZ concentrations ranging from 1 to 30 μM, with a detection limit of 5.41 nM. This method was successfully applied to quantify CBZ in food samples, achieving excellent recoveries of 99% with a relative standard deviation (RSD) of less than 2%., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Easy, economical, and swift detecting tools are very demanded for assaying various chemical species. The introduction of label-free paper-based read-out devices has significantly reached the demand of analytical science for target analytes assays. Herein, a facile, and disposable inexpensive paper-based sensing tool was fabricated for sensing As 3+ ion using graphene quantum dots (GQDs) as a fluorescent reader. The CA-GQDs were synthesized using citric acid (CA) as a precursor via the pyrolysis method, further physisorbed on the cellulose substrate for sensing of As 3+ via aggregation-based fluorescence "turn-off" mechanism. The linear range for quantitating As 3+ ion is in the range of 0.05-50 μM with a detection limit of 10 nM. The practical application of the CA-GQDs-based analytical platform was verified by assaying As 3+ ion in water samples. The CA-GQDs-embedded paper strip can be easily extended for assaying of As 3+ ion, which meets the demand for monitoring of As 3+ ion in real samples., (© 2024 John Wiley & Sons, Ltd.)

Copper nanoclusters (Cu NCs) have shown significant attention in sensing of molecular and ionic species. In this work, a single-step biosynthetic approach was introduced for the preparation of fluorescent Cu NCs using Holarrhena pubescens (H. pubescens) leaves extract as a template. The synthesized H. pubescens-Cu NCs act as a nanomolecular probe for the detection of bilirubin in biofluids. The synthesized H. pubescens-Cu NCs displayed highest fluorescence intensity at 454 nm, when excited at 330 nm. Importantly, selective detection of bilirubin was obtained by introducing H. pubescens-Cu NCs as a simple molecular probe. The interaction of bilirubin and H. pubescens-Cu NCs resulted in a remarkable decrease in the emission peak intensity. The developed H. pubescens-Cu NCs-based bilirubin molecular probe has a wide linear range of 0.5-20.00 μM with the limit of detection of 30.54 nM for bilirubin. The promising application of H. pubescens-Cu NCs-based molecular probe was assessed by assaying bilirubin in spiked biofluids., (© 2024 John Wiley & Sons Ltd.)

The non-invasive nature and potential for sustained release make transdermal drug administration an appealing treatment option for cancer therapy. However, the strong barrier of the stratum corneum (SC) poses a challenge for the penetration of hydrophilic chemotherapy drugs such as 5-fluorouracil (5-FU). Due to its biocompatibility and capacity to increase drug solubility and permeability, especially when paired with chemical enhancers, such as oleic acid (OA), which is used in this work, choline glycinate ([Cho][Gly]) has emerged as a potential substance for transdermal drug delivery. In this work, we examined the possibility of transdermal delivery of 5-FU for the treatment of breast cancer using an ionic hydrogel formulation consisting of [Cho][Gly] with OA. Small angle neutron scattering, rheological analysis, field emission scanning electron microscopy, and dynamic light scattering analysis were used to characterize the ionic hydrogel. The non-covalent interactions present between [Cho][Gly] and OA were investigated by computational simulations and FTIR spectroscopy methods. When subjected to in vitro drug permeation using goat skin in a Franz diffusion cell, the hydrogel demonstrated sustained release of 5-FU and effective permeability in the order: [Cho][Gly]-OA gel > [Cho][Gly] > PBS (control). The hydrogel also demonstrated 92% cell viability after 48 hours for the human keratinocyte cell line (HaCaT cells) as well as the normal human cell line L-132. The breast cancer cell line MCF-7 and the cervical cancer cell line HeLa were used to study in vitro cytotoxicity that was considerably affected by the 5-FU-loaded hydrogel. These results indicate the potential of the hydrogel as a transdermal drug delivery vehicle for the treatment of breast cancer.

Transdermal drug delivery systems (TDDS) are a promising and innovative approach for breast cancer treatment, offering advantages such as noninvasiveness, potential for localized and prolonged drug delivery while minimizing systemic side effects through avoiding first-pass metabolism. Utilizing the distinctive characteristics of hydrogels, such as their biocompatibility, versatility, and higher drug loading capabilities, in the present work, we prepared ionic hydrogels through synergistic interaction between ionic liquids (ILs), choline alanine ([Cho][Ala]), and choline proline ([Cho][Pro]) with oleic acid (OA). ILs used in the study are biocompatible and enhance the solubility of 5-fluorouracil (5-FU), whereas OA is a known chemical penetration enhancer. The concentration-dependent (OA) change in morphological aggregates, that is, from cylindrical micelles to worm-like micelles to hydrogels was formed with both ILs and was characterized by SANS measurement, whereas the interactions involved were confirmed by FTIR spectroscopy. The hydrogels have excellent mechanical properties, which studied by rheology and their morphology through FE-SEM analysis. The in vitro skin permeation study revealed that both hydrogels penetrated 255 times ([Cho][Ala]) and 250 times ([Cho][Pro]) more as compared to PBS after 48 h. Those ionic hydrogels exhibited the capability to change the lipid and keratin arrangements within the skin layer, thereby enhancing the transdermal permeation of the 5-FU. Both ionic hydrogels exhibit excellent biocompatibility with normal cell lines (L-132 cells) as well as cancerous cell lines (MCF-7 cells), demonstrating over 92% cell viability after 48 h in both cell lines. In vitro, the cytotoxicity of the 5-FU-loaded hydrogels was evaluated on MCF-7 and HeLa cell lines. These results indicate that the investigated biocompatible and nontoxic ionic hydrogels enable the transdermal delivery of hydrophilic drugs, making them a viable option for effectively treating breast cancer.

Blue emissive Argyreia nervosa-capped gold nanoclusters (A. nervosa-AuNCs) were synthesized via a simple environment-friendly method. The developed probe exhibits rapid response towards the target analyte (hexaconazole fungicide). Several characterizations, including FT-IR, UV-visible, fluorescence, HR-TEM, XPS, and fluorescence lifetime, were studied to confirm the formation of A. nervosa-AuNCs. The A. nervosa-AuNCs displayed emission and excitation peaks at 470 and 390 nm, respectively. Furthermore, the quantum yield (QY) of A. nervosa-AuNCs was 21.25%. The as-synthesized A. nervosa-AuNCs showed a good linear response with hexaconazole in the concentration range of 0.025-180 μM, with a detection limit (LOD) of 21.94 nM, indicating A. nervosa-AuNCs could be used as a sensitive and selective probe for detecting hexaconazole through a fluorescence "turn-off" mechanism. The A. nervosa-AuNCs were successfully used to detect hexaconazole in real samples. Moreover, A. nervosa-AuNCs were used as a bio-imaging probe for visualization of Saccharomyces cerevisiae cells., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Fluorescent metal nanoclusters (MNCs) have found extensive application in recognizing molecular species. Here, orange-red fluorescent Arg-A. paniculata-MoNCs were synthesized using Andrographis paniculata leaf extract, arginine as a ligand, and MoCl 5 as a metal precursor. The Arg-A. paniculata-MoNCs complex exhibited a quantum yield (QY) of 16.91% and excitation/emission wavelengths of 400/665 nm. The synthesized Arg-A. paniculata-MoNCs successfully acted as a probe for assaying neomycin sulphate (NS) via fluorescence turn-off and K + ions via fluorescence turn-on mechanisms, respectively. Moreover, the developed probe was effectively used to develop a cellulose paper strip-based sensor for detection of NS and K + ions. Arg-A. paniculata-MoNCs demonstrated great potential for sensing NS and K + ions, with concentration ranges of 0.1-80 and 0.25-110 μM for NS and K + ions, respectively. The as-synthesized Arg-A. paniculata-MoNCs efficiently detected NS and K + ions in food and biofluid samples, respectively., (© 2024 John Wiley & Sons Ltd.)

The exceptional ascending heights of graphene (carbon) and boron nitride nanostructures have invited scientists to explore metal nitride nanomaterials. Herein, Zn 3 N 2 quantum dots (QDs) were prepared via a simple hydrothermal route from the reaction between zinc nitrate hexahydrate and ammonia solution that possess efficient strength towards sensing applications of metal ions (Cu 2+ and Mn 2+ ). The as-prepared Zn 3 N 2 QDs show bright fluorescence, displaying an emission peak at 408 nm upon excitation at 320 nm, with a quantum yield (QY) of 29.56%. It was noticed that the fluorescence intensity of Zn 3 N 2 QDs linearly decreases with the independent addition of Cu 2+ and Mn 2+ ions, displaying good linearity in the ranges 2.5-50 µM and 0.05-5 µM with detection limits of 21.77 nM and of 63.82 nM for Cu 2+ and Mn 2+ ions, respectively. The probe was successfully tested for quantifying Cu 2+ and Mn 2+ in real samples including river, canal, and tap water, providing good recoveries with a relative standard deviation  < 2%. Furthermore, the masking proposition can successfully eliminate the interference if the two metal ions exist together. It was found that thiourea is efficiently able to mask Cu 2+ and selectively quenches Mn 2+ , and L-cysteine is able to halt the quenching potential of Mn 2+ and is selectively able to sense Cu 2+ . The Zn 3 N 2 QDs provide a simple way for the simultaneous detection of both Cu 2+ and Mn 2+ ions in environmental samples at low sample preparations requirements., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Extracellular protein kinase A autoantibody (ECPKA-AutoAb) has been suggested as a universal cancer biomarker due to its higher amounts in serum of several types of cancer patients than that of normal individuals. Herein, we first developed a lateral flow immunoassay (LFIA) tool, using a sandwich format, toward ECPKA-AutoAb in human serum. For this format, 3G2 as a capture antibody was identified using hybridoma technique and a series of screenings where it showed superior capacity to recognize Enzo PKA catalytic subunit alpha (Cα), compared to other PKA antibodies and antigens. Using these components, we performed sandwich ELISA toward a mimic and real sample of ECPKA-AutoAb. As per the results, limit of detection (LOD) was found to be 135 ng/mL and ECPKA-AutoAb levels were higher in various cancer patients than in normal individuals like previous studies. Based on these results, we applied this sandwich format into LFIA tool and found that the LOD of the fabricated LFIA tool showed about 3.8 ng/mL using spiked PKA-Ab, which is significantly improved compared to the LOD of sandwich ELISA. Also, the developed LFIA tool demonstrated a remarkable ability to detect significant differences in ECPKA-AutoAb levels between normal and cancer patients within 15 min, showing a potential for point-of-care (PoC) detection. One interesting point is that our LFIA strip contains an additional conjugation pad II, named because of its position behind the conjugation pad, in which PKA Cα is dried, enabling a sandwich format., 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 B.V. All rights reserved.)

In this study, water-soluble carbon dots (CDs) were employed as a novel fluorescence "turn OFF-ON" sensor to detect Fe 3+ ions in pharmaceutical sample and propiconazole (PC) in food samples. Blue fluorescent "LPCDs" are synthesized from the lemon peel that exhibited emission at 468 nm when excited at 378 nm. The average size of the as-prepared LPCDs is 2.03 nm, displaying a quantum yield of 32 %. Fluorescence "turn OFF-ON" strategy was developed for sensing of Fe 3+ ion and PC, demonstrating favorable linearity in the range of 0.5-180 μM and 0.1-40 μM with the detection limits of 0.18 μM and 0.054 μM for Fe 3+ and PC, respectively. Further, LPCDs-loaded cellulose paper was used as visual reader to detect Fe 3+ and PC. This approach was effectively applied to detect Fe 3+ and PC in pharmaceutical and vegetable samples., 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.)

In this work, a facile one-step green synthesis was developed for the fabrication of blue fluorescent copper nanocluster (Brahmi-CuNCs) from the extract of Bacopa monnieri (common name is Brahmi) via a microwave method. The as-prepared Brahmi-CuNCs emitted blue fluorescence at 452 nm when excited at 352 nm and showed a quantum yield of 31.32%. Brahmi-derived blue fluorescent CuNCs acted as a probe for fluorescence sensing of dichlorvos. Upon the addition of dichlorvos, the blue emission for Brahmi-CuNCs was gradually turned off, favouring establishment of a calibration graph in the range 0.5-100 μM with a detection limit of 0.23 μM. The as-synthesized Brahmi-CuNCs exhibited marked sensitivity and selectivity towards dichlorvos, favourable for assaying dichlorvos in various samples (cabbage, apple juice, and rice)., (© 2023 John Wiley & Sons Ltd.)

In this work, we have synthesized four different color (yellow, orange, green, and blue (multicolor)) silver nanostructures (AgNSs) by chemical reduction method where silver nitrate, sodium borohydride and hydrogen peroxide were used as reagents. The as-synthesized multicolor AgNSs were successfully functionalized with bovine serum albumin (BSA) and applied as a colorimetric sensor for the assaying of metal cations (Cr 3+ , Hg 2+ , and K + ). The addition of metal ions (Cr 3+ , Hg 2+ , and K + ) into BSA functionalized AgNSs (BSA-AgNSs) causes the aggregation of BSA-AgNSs, and are accompanied by visual color changes with red or blue shift in the surface plasmon resonance (SPR) band of BSA-AgNSs. The BSA-AgNSs show different SPR characteristic for each metal ions (Cr 3+ , Hg 2+ , and K + ) with exhibiting different spectral shift and color change. The yellow color BSA-AgNSs (Y-BSA-AgNSs) act as a probe for sensing Cr 3+ , orange color BSA-AgNSs (O-BSA-AgNSs) act as probe for Hg 2+ ion assay, green color BSA-AgNSs (G-BSA-AgNSs) act as a probe for the assaying of both K + and Hg 2+ , and blue color BSA-AgNSs (B-BSA-AgNSs) act as a sensor for colorimetric detection of K + ion. The detection limits were found to be 0.26 μM for Cr 3+ (Y-BSA-AgNSs), 0.14 μM for Hg 2+ (O-BSA-AgNSs), 0.05 μM for K + (G-BSA-AgNSs), 0.17 μM for Hg 2+ (G-BSA-AgNSs), and 0.08 μM for K + (B-BSA-AgNSs), respectively. Furthermore, multicolor BSA-AgNSs were also applied for assaying of Cr 3+ , and Hg 2+ in industrial water samples and K + in urine sample., 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 Inc. All rights reserved.)

In the past 2 decades, multicolour light-emissive nanomaterials have gained significant interest in chemical and biological sciences because of their unique optical properties. These materials have drawn much attention due to their unique characteristics towards various application fields. The development of novel nanomaterials has become the pinpoint for different application areas. In this review, the recent progress in the area of multicolour-emissive nanomaterials is summarized. The different emissions (white, orange, green, red, blue, and multicolour) of nanostructure materials (metal nanoclusters, quantum dots, carbon dots, and rare earth-based nanomaterials) are briefly discussed. The potential applications of different colour-emissive nanomaterials in the development of fluorescent inks, light-emitting diodes, cell imaging, and sensing devices are briefly summarized. Finally, the future perspectives of multicolour-emissive nanomaterials are discussed., (© 2022 John Wiley & Sons Ltd.)

The fabrication of stable fluorescent MoNCs (molybdenum nanoclusters) in aqueous media is quite challenging as it is not much explored yet. Herein, we report a facile and efficient strategy for fabricating MoNCs using 2,3 dialdehyde maltose-cysteine Schiff base (DAM-cysteine) as a ligand for detecting myoglobin and γ-aminobutyric acid (GABA) in biofluids with high selectivity and sensitivity. The DAM-cysteine-MoNCs displayed fluorescence of bright blue color under a UV light at 365 nm with an emission peak at 444 nm after excitation at 370 nm. The synthesized DAM-cysteine-MoNCs were homogeneously distributed with a mean size of 2.01 ± 0.98 nm as confirmed by the high-resolution transmission electron microscopy (HR-TEM). Further, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) techniques were utilized to confirm the elemental oxidation states and surface functional groups of the DAM-cysteine-MoNCs. After the addition of myoglobin and GABA, the emission peak of DAM-cysteine-MoNCs at 444 nm was significantly quenched. This resulted in the development of a quantitative assay for the detection of myoglobin (0.1-0.5 μM) and GABA (0.125-2.5 μM) with the lower limit of detection as 56.48 and 112.75 nM for myoglobin and GABA, respectively., (© 2023 John Wiley & Sons Ltd.)

This review briefly emphasizes the different detection approaches (electrochemical sensors, chemiluminescence, surface-enhanced Raman scattering), functional nanostructure materials (quantum dots, metal nanoparticles, metal nanoclusters, magnetic nanomaterials, metal oxide nanoparticles, polymer-based nanomaterials, and carbonaceous nanomaterials) and detection mechanisms. Furthermore, the emphasis of this review is on the integration of functional nanomaterials with optical spectroscopic techniques for the identification of various biomarkers (nucleic acids, glucose, uric acid, oxytocin, dopamine, ascorbic acid, bilirubin, spermine, serotonin, thiocyanate, Pb 2+ , Cu 2+ , Hg 2+ , F - , peptides), and cancer biomarkers (mucin 1, prostate specific antigen, carcinoembryonic antigen, CA15-3, human epidermal growth factor receptor 2, C-reactive protein, and interleukin-6). Analytical characteristics of nanomaterials-based optical sensors are summarized in the tables, providing the insights of nanomaterials-based optical sensors for biomarkers detection. Finally, the opportunities and challenges of nanomaterials-based optical analytical approaches for the detection of various biomarkers (inorganic, organic, biomolecules, peptides and proteins) are discussed., (© 2022 John Wiley & Sons Ltd.)

Identification of trace level chemical species (drugs, pesticides, metal ions and biomarkers) plays key role in environmental monitoring. Recently, fluorescence assay has shown significant advances in detecting of trace level drugs, pesticides, metal ions and biomarkers in real samples. Ultra-small nanostructure materials (metal nanoclusters (NCs), quantum dots (QDs) and carbon dots (CDs)) have been integrated with fluorescence spectrometer for sensitive and selective analysis of trace level target analytes in various samples including environmental and biological samples. This review summarizes the properties of metal NCs and ligand chemistry for the fabrication of metal NCs. We also briefly summarized the synthetic routes for the preparation of QDs and CDs. Advances of ultra-small fluorescent nanosensors (NCs, QDs and CDs) for sensing of metal ions, drugs, pesticides and biomarkers in various sample matrices are briefly discussed. Additionally, we discuss the recent challenges and future perspectives of ultra-small materials as fluorescent sensors for assaying of wide variety of target analytes in real samples., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Gold nanostars (AuNSs) are synthesized using a seed-mediated growth method. The synthesized AuNSs solution is stable and shows a localized surface plasmon resonance (LSPR) band in the visible range, which is confirmed using ultraviolet-visible (UV-Vis) spectroscopy. Furthermore, the as-synthesized AuNSs were functionalized with melamine and used as a sensor for the colorimetric detection of uric acid (UA). The detection mechanism could be assessed through various analytical techniques such as UV-Vis spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, dynamic light scattering (DLS), zeta potential, field emission scanning electron microscopy (FE-SEM), and transmission electron microscopic techniques. These methods exhibited a good linear regression between the absorption ratio of LSPR band of melamine-AuNSs and the concentration of UA (0-120 µM), with the detection limit of 8.50 nm. As a result, UA was quantitatively detected in biofluids by using melamine-AuNSs as a colorimetric sensor, revealing melamine-AuNSs-based colorimetric approach which could be used as a simple platform for UA assay in biofluids.

Herein, glutathione-ascorbic acid-functionalized molybdenum oxide quantum dots (GSH-AA-MoO x QDs) are synthesized by the conventional method and used as a fluorescent probe for the rapid detection of isoniazid drug in pharmaceutical samples. Ascorbic acid and glutathione are used as surface ligands for the modification of MoO x QDs. The as-synthesized GSH-AA-MoO x QDs display λ Em at 416 nm when applied λ Ex at 330 nm. The introduction of isoniazid drug into GSH-AA-MoO x QDs solution results the assembly of GSH-AA-MoO x QDs-isoniazid nanoarchitectures, leading to quench λ Em at 416 nm. Thus, GSH-AA-MoO x QDs can work as a fluorescent sensor for the rapid identification of isoniazid in real samples. The as-prepared GSH-AA-MoO x QDs not only allows superior analytical features (rapidity, and selectivity) toward isoniazid with the detection limit of 94 nM, but also displays fluorescence "turn-off" response for assaying of isoniazid in real samples (pharmaceutical and biofluids). Finally, GSH-AA-MoO x QDs are highly promising fluorescent probe for the rapid detection of isoniazid in real samples., 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 © 2022 Elsevier B.V. All rights reserved.)

Technology integration of nanomaterials with microbial fuel cell (MFC) have led to simultaneous degradation of recalcitrant dyes and energy extraction from textile wastewater. Limited electron transfer capacity and hydrophobicity of electrode are the bottlenecks for enhancing the performance of MFC. Nanomaterials can provide surface functionalities for electron transfers and serve as catalyst for pollutant degradation. In this paper, magnetite nanoparticles functionalized with carbon dots (Fe 3 O 4 @CDs) were used to enhance the electron transfer capacity of the electrodes due to numerous surface-active functional groups of CDs and the reversible redox reaction of Fe 2+ /Fe 3+ . Polydopamine (PDA) was used as binder to coat Fe 3 O 4 @CDs onto the surface of carbon felt (CF) electrodes in a sono-chemical reaction, favoring to form biocompatible electrodes. Charge transfer resistance of Fe 3 O 4 @CDs@PDA-CF was 5.02Ω as compared to 293.34Ω of unmodified CF. Fe 3 O 4 @CDs@PDA-CF installed MFC could achieve almost 98% dye degradation efficiency within 48 h and 18.30 mW m -2 power output as compared to 77% dye degradation and 0.34 mW m -2 power output by unmodified CF electrode MFC. Moreover, metagenomic analysis of microbial consortia developed in Fe 3 O 4 @CDs@PDA-CF MFC showed enrichment of electrogenic and dye degrading microbial communities of Achromobacter. Delftia, Geobacter and Pseudomonas., 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 © 2022 Elsevier Ltd. All rights reserved.)

MXenes are an innovative class of 2D nanostructured materials gaining popularity for various uses in medicine, chemistry, and the environment. A larger outer layer area, exceptional stability and conductivity of heat, high porosity, and environmental friendliness are all characteristics of MXenes and their composites. As a result, MXenes have been used to produce Li-ion batteries, semiconductors, water desalination membranes, and hydrogen storage. MXenes have recently been used in many environmental remediations, frequently surpassing conventional materials, to treat groundwater contamination, surface waters, industrial and municipal wastewaters, and desalination. Due to their outstanding structural characteristics and the enormous specific surface area, they are widely utilized as adsorbents or membrane materials for the desalination of seawater. When used for electrochemical applications, MXene-composites can deionize via Faradaic capacitive deionization (CDI) and adsorb various organic and inorganic pollutants to treat the water. In general, as compared to other 2D nanomaterials, MXene has superb characteristics; because of their magnificent characteristics and they exhibit strong desalination capability. The current review paper discusses the desalination capability of MXenes and their composites. Focusing on the desalination capacity of MXene-based nanomaterials, this study discusses the characteristics and synthesis techniques of MXenes their composites along with their ion-rejection capability and pervaporation desalination of water via MXene-based membranes, capacitive deionization capability, solar desalination capability. Furthermore, the challenges and prospects of MXenes and their composites are highlighted., 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 © 2022 Elsevier Ltd. All rights reserved.)

In this work, bimetallic gold and copper nanoclusters (Au-Cu NCs) were fabricated by using papain as a ligand. The as-synthesized papain-Au-Cu NCs displayed red fluorescence at 365 nm of UV lamp. The as-prepared papain-Au-Cu NCs display a strong fluorescence at 656 nm when excited at 390 nm. Papain encapsulated Au-Cu NCs exhibit distinct interaction site towards cortisone, which results red fluorescence "turn-off". Papain-Au-Cu NCs exhibited a rapid response and remarkable fluorescence quenching with the addition of cortisone as a biomarker. The developed probe is demonstrated for the quantification of cortisone by plotting the calibration graph between the fluorescence ratio (I 0 /I) and cortisone concentration (0.031-1.00 μM) with an impressive detection limit of 1.89 nM. Interestingly, the response of papain-Au-Cu NCs towards other biomarkers and common interfering species is quite silent, signifying the selectivity of papain-Au-Cu NCs for the detection of cortisone. The probe was successfully applied to assay cortisone biomarker in urine and plasma samples. More importantly, the analytical validation of the probe was assessed by assaying cortisone in intra- and inter-day, demonstrating papain-Au-Cu NCs could serve as promising probe for the rapid detection of cortisone in biological samples., (© 2022. Springer-Verlag GmbH Germany, part of Springer Nature.)

Metal ions or clusters that have been bonded with organic linkers to create one- or more-dimensional structures are referred to as metal-organic frameworks (MOFs). Reticular synthesis also forms MOFs with properly designated components that can result in crystals with high porosities and great chemical and thermal stability. Due to the wider surface area, huge pore size, crystalline nature, and tunability, numerous MOFs have been shown to be potential candidates in various fields like gas storage and delivery, energy storage, catalysis, and chemical/biosensing. This study provides a quick overview of the current MOF synthesis techniques in order to familiarize newcomers in the chemical sciences field with the fast-growing MOF research. Beginning with the classification and nomenclature of MOFs, synthesis approaches of MOFs have been demonstrated. We also emphasize the potential applications of MOFs in numerous fields such as gas storage, drug delivery, rechargeable batteries, supercapacitors, and separation membranes. Lastly, the future scope is discussed along with prospective opportunities for the synthesis and application of nano-MOFs, which will help promote their uses in multidisciplinary research., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

In this work, terephthaldehyde-cysteine-molybdenum nanoclusters (TPA-Cys-MoNCs) were synthesized by using terephthaldehyde-cysteine (TPA-Cys) Schiff base as a novel ligand. The as-synthesized TPA-Cys-MoNCs showed blue fluorescence under UV lamp at 365 nm, displaying emission peak at 455 nm when excited at 340 nm. The fluorescent TPA-Cys-MoNCs are used as a probe for sensitive assay of pyrophosphate (PPi) via fluorescence quenching mechanism. The emission peak intensity of TPA-Cys-MoNCs at 455 nm exhibited a linear quenching with increasing amount of PPi. As a result, quantitative assay was developed for the detection of PPi (0.01-200 µM) with the detection limit of 0.9 nM. The developed probe was successfully demonstrated for the detection of PPi in biofluids (urine and plasma)., (Copyright © 2022 Elsevier B.V. All rights reserved.)

In this work, a microwave assisted method was developed for synthesis of red fluorescent copper nanoclusters (NCs) using trypsin as a template (trypsin-Cu). The as-synthesized trypsin-Cu NCs are stable and water soluble, exhibiting fluorescence emission at 657 nm when excited at 490 nm. The as-prepared red-emitting trypsin-Cu NCs were characterized by using several analytical techniques such as ultraviolet-visible (UV-Vis) and fluorescence, fluorescence lifetime, Fourier transform infrared, and X-ray photoelectron spectroscopic techniques. Red-emitting trypsin-Cu NCs acted as a nanosensor for sensing both Pb 2+ and Hg 2+ ions through fluorescence quenching. Using this approach, good linearities are observed in the range of 0.1-25 and of 0.001-1 μM with the lower limit of detection of 14.63 and 56.81 nM for Pb 2+ and Hg 2+ ions, respectively. Trypsin-Cu NCs-based fluorescence assay was successfully applied to detect both Hg 2+ and Pb 2+ ions in water and tobacco samples.

Lab-on-a-chip devices have now-a-days become an important aspect of analytical/bioanalytical chemistry having wide range of applications including clinical diagnosis, drug screening, cell biology, environmental monitoring, food safety analysis etc. Conventional lab-on-a-chip devices generally employ chemicals that are not environmentally friendly and were commonly fabricated on hard plastic platform which are non-degradable and hence ignore the importance of green analytical chemistry. In today's scenario, it is highly imperative to protect our environment by using less toxic and environmentally friendly chemicals/solvents and biocompatible platforms. Accordingly, the present article comprehensively reviews on the various green aspects of lab-on-a-chip devices for analytical processes which aim at fabricating environmentally friendly and cost-effective downsized devices so that the risk factor at the user's end upon longer exposure as well as to the environment can be reduced. The decisive factors for the accomplishment of green aspects of lab-on-a-chip devices including sample preparation using lab-on-a-chip systems to minimize the amount of sample/solvents to few microliters only, substitution of harmful solvents with green alternatives, minimal waste generation or proper treatment of waste and biodegradable and biocompatible platforms for fabricating lab-on-a-chip devices have been discussed in details. Additionally, the challenges that may hinder their commercialization are also critically discussed., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Lanthanide-doped upconversion nanoparticles (UCNPs) have gained more attention from researchers due to their unique properties of photon conversion from an excitation/incident wavelength to a more suitable emission wavelength at a designated site, thus improving the scope in the life sciences field. Due to their fascinating and unique optical properties, UCNPs offer attractive opportunities in theranostics for early diagnostics and treatment of deadly diseases such as cancer. Also, several efforts have been made on emerging approaches for the fabrication and surface functionalization of luminescent UCNPs in optical biosensing applications using various infrared excitation wavelengths. In this review, we discussed the recent advancements of UCNP-based analytical chemistry approaches for sensing and theranostics using a 980 nm laser as the excitation source. The key analytical merits of UNCP-integrated fluorescence analytical approaches for assaying a wide variety of target analytes are discussed. We have described the mechanisms of the upconversion (UC) process, and the application of surface-modified UCNPs for in vitro / in vivo bioimaging, photodynamic therapy (PDT), and photothermal therapy (PTT). Based on the latest scientific achievements, the advantages and disadvantages of UCNPs in biomedical and optical applications are also discussed to overcome the shortcomings and to improve the future study directions. This review delivers beneficial practical information of UCNPs in the past few years, and insights into their research in various fields are also discussed precisely.

The assay of alkaline phosphatase (ALP) plays a key role in the diagnosis of various diseases. Herein, folic acid functionalized molybdenum oxide quantum dots (FA-MoO x QDs) are explored as fluorescence "turn- off and on" probes for assaying of Cu 2+ ion and ALP, respectively. This fluorescence sensing strategy was based on the quenching of emission peak of FA-MoO x QDs at 445 nm by Cu 2+ ion, followed by restoring of emission peak selectively with ALP. Based on the quenching and restoring of FA-MoO x QDs emission intensity, quantitative assay was developed for the detection of Cu 2+ ion (0.20 - 500 µM) and ALP (0.06 - 150 U/L) with detection limits of 29 nM and 0.026 U/L, respectively. The developed FA-MoO x QDs-based fluorescence "turn- off and on" strategy exhibited satisfactory results for assaying of ALP in biofluids., 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 © 2021 Elsevier B.V. All rights reserved.)

Convenient one-pot synthetic route for the fabrication of carbon dots (CDs) from Tagetes erecta flower (TEF), named as "TEF-CDs', through solvo(hydro)-thermal carbonization of the TEF was developed. The TEF-CDs revealed high selectivity towards chlorpyrifos and quinalphos, acting as a fluorescent probe. The CDs synthesized from T. erecta flower showed a strong blue color at 495 nm when excited at 420 nm, along with the exhibition of a strong quantum yield of 63.7%. The synthesized CDs revealed their richness in the surface-active organic group that synthesized CDs from T. erecta flower are mainly comprised of C, O, and N, which were crystalline in structure that was revealed by TEM image and XRD spectra. Furthermore, when the probe was exposed to different pH conditions, no major noticeable changes were recorded. Moreover, when the probe was exposed to chlorpyrifos and quinalphos, we have noticed that fluorescence spectra was turned off when the probe was exposed to chlorpyrifos and "turned on" after the exposure quinalphos. Moreover, fluorescence spectral changes showed a good linearity with chlorpyrifos and quinalphos concentrations in the range of 0.05-100.0 μM for chlorpyrifos and 0.01-50.0 μM for quinalphos. The limit of detection are 2.1 ng mL -1 and 1.7 ng mL -1 for chlorpyrifos and quinalphos, respectively. Finally, the TEF-CDs-based fluorescent nanoprobe was successfully applied to estimate chlorpyrifos and quinalphos with an effective accuracy in rice and fruit samples with rapid detection time., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Currently, the 2019 novel coronavirus (2019-nCoV) is drastically affecting 214 countries, causing severe pneumonia in patients, which has resulted in lockdown being implemented in several countries to stop its local transmission. Considering this, the rapid screening and accurate detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; 2019-nCoV) play an essential role in the diagnosis of COVID-19, which can minimize local transmission and prevent an epidemic. Due to this public health emergency, the development of ultra-fast reliable diagnostic kits is essential for the diagnosis of COVID-19. Recently, molecular biology and nanotechnology based analytical methods have proven to be promising diagnostic tools for the rapid screening of 2019-nCoV with high accuracy and precision. The main aim of this review is to provide a retrospective overview on the molecular biology tools (reverse transcription polymerase chain reaction (RT-PCR) and reverse transcription loop-mediated isothermal amplification (RT-LAMP)) and nanotechnology based analytical tools (enzyme-linked immunosorbent assay (ELISA), RT-PCR, and lateral flow assay) for the rapid diagnosis of COVID-19. This review also presents recent reports on other analytical techniques including paper spray mass spectrometry for the diagnosis of COVID-19 in clinical samples. Finally, we provide a quick reference on molecular biology and nanotechnology based analytical tools for COVID-19 diagnosis in clinical samples.

The detection of bovine viral diarrhea virus (BVDV), which is a pathogen inducing fatal gastrointestinal disease in cattle, is becoming a momentous issue in the livestock farm. In that, BVDV is related to inapparent infection and various diseases with high transmissibility; it has also led to considerable economic losses. In this study, a simple dot-blotting method was devised to construct a rapid screening system for BVDV. Based on the BVDV-specific bioreceptors, it was anchored on the gold nanoparticles (AuNPs) to generate the seeding sites for signaling; then the signals were amplified by adopting the overgrowth of copper nano-polyhedral shells on AuNPs. The developed detection system shows a low detection limit of 4.4 copies per mL, and even this could be distinguished with naked eyes. These results indicate that the designed nanobiosensor possesses not only high sensitivity and selectivity but also potential usage on a point-of-care testing platform for BVDV., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Nowadays, fluorescent molybdenum disulfide quantum dots (MoS 2 QDs) have proven to be potential candidates in the sensing and bioimaging areas owing to their exceptional intrinsic characteristics. Here, a simple hydrothermal strategy was explored for the preparation of MoS 2 QDs using ammonium heptamolybdate and 6-mercaptopurine (6-MP) as precursors. The emission peak of MoS 2 QDs was significantly quenched in the presence Cr 3+ ion due to the selective surface chemistry on the surfaces of MoS 2 QDs. The designed fluorescent MoS 2 QDs showed a linear fluorescence quenching response with increasing concentration of Cr 3+ ion (0.1-10 μM), allowing to detect Cr 3+ ion even at 0.08 μM. This fluorescent MoS 2 QDs were utilized for the quantification of Cr 3+ ion in real samples (water and biological samples). Interestingly, the synthesized MoS 2 QDs exhibited negligible cytotoxicity on NRK cells and acted as good candidates for imaging of Trichoderma viride fungal cells., Competing Interests: Declaration of competing interest The authors declare no competing financial interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Photodynamic therapy is an emerging noninvasive cancer treatment approach, which requires a photosensitizer (PS), light, and molecular oxygen. In this study, we have successfully fabricated a dual nature (pH- and reactive-oxygen-species-responsive) upconversion nanoparticles (UCNPs) to utilize coloaded doxorubicin (DOX) and chlorin e6 (Ce6) with high antitumor efficacy. The model anticancer drug (DOX) and PS (Ce6) were conjugated in a ratio of 1:1 (w:w), and then loaded on the surface of UCNPs@mesoporous silica (mSiO 2 ) (85.63 ± 9.87 nm). Cellular uptake could be achieved by either increased permeability or ionic effect of UCNPs@mSiO 2 , where Ce6 controlled the DOX release under a near-infrared (NIR) laser irradiation at 980 nm. A cytotoxicity analysis revealed that the dual-responsive UCNPs@mSiO 2 could successfully deliver DOX and Ce6 at the tumor site, causing cell death with a high efficiency. This study shows that the modified UCNPs@mSiO 2 is a promising system to realize NIR-light-triggered PS and drug delivery approach to improve synergistic therapies in vitro and in vivo, in the future., Competing Interests: Declaration of competing interest The authors declare no competing financial interest. To the best of our knowledge, the named authors have no conflict of interest, financial or otherwise., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The development of novel methods plays a fundamental role in early diagnosis and controlling of neurological disorders (NDs). Blood-brain barrier (BBB) is the most challenging barrier for the development of neuro drug delivery systems due to its inhibiting ability to enter drugs and agents into central nervous system (CNS). Carbon dots (CDs) have shown to be very promising and outstanding agents for various biomedical applications (bio imaging studies, treatment of NDs and brain tumors). They exhibit remarkable properties such as biocompatibility, small size (less than 10 nm, enabling penetration into BBB), tunable optical properties, photostability and simple synthetic procedures, allowing them to act as ideal candidates in various fields of science. Therefore, the objective of this review is to overview the recent studies on CDs for the development of neuro drug delivery systems to reach CNS via crossing of BBB. Primarily, this review briefly outlines the unique optical properties and toxicity of CDs. The development of novel neuro drug delivery systems for various neurological disorders using CDs as carriers is described. This review also covers the potential applications of CDs in brain tumors imaging and treatment of neurodegenerative diseases. Finally, the sensing applications and future prospects of CDs are summarized., (Copyright © 2020 Elsevier B.V. All rights reserved.)

A novel electrospinning approach is proposed for the fabrication of copper (Cu)-nanoflower decorated gold nanoparticles (AuNPs)-graphene oxide (GO) nanofiber (NF) as an electrochemical biosensor for the glucose detection. In this study, GO was mixed with poly(vinyl alcohol) (PVA) and used as a fiber precursor, which greatly improves the electrochemical properties. The above solution was uniformly coated onto the surfaces of gold chip to form GO NFs via electrospinning. AuNPs were coated onto the surface of GO NFs and then incorporated organic-inorganic hybrid nanoflower [Cu nanoflower-glucose oxidase (GOx) and horseradish peroxidase (HRP)]. The electrochemical experiments revealed that Cu-nanoflower@AuNPs-GO NFs exhibited outstanding electrochemical catalytic nature, and selectivity for the conversion of glucose to gluconic acid in the presence of GOx-HRP-Cu nanoflower. The Cu-nanoflower@AuNPs-GO NFs coated Au chip exhibited good linear range 0.001-0.1 mM, with a detection limit of 0.018 μM. The Cu-nanoflower@AuNPs-GO NFs modified Au chip exhibited higher catalytic properties, which are attributed to the coating of unique organic-inorganic nanostructured materials on the surfaces of Au chip. These results indicate that the nano-bio hybrid materials can be applied as a promising electrochemical biosensor to monitor glucose levels in biofluids., (Copyright © 2019 Elsevier B.V. All rights reserved.)

A facile and novel nanosensor analytical strategy was developed for the colorimetric detection of pencycuron fungicide in rice, potato, cabbage, and water samples based on the pencycuron-induced aggregation of 6-aza-2-thiothymine-functionalized gold nanoparticles (ATT-AuNPs). The ATT-AuNPs exhibited good stability and were characterized with UV-visible spectroscopy, Fourier transform infrared (FT-IR) spectrometry, field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), and zeta potential techniques. The addition of pencycuron facilitated strong non-covalent interactions (electrostatic, van der Waals, and H bonding) between pencycuron and ATT-AuNPs, inducing a significant red shift in the surface plasmon resonance (SPR) peak of ATT-AuNPs along with a color change from red to blue. A linear equation was established between absorption ratio (A 720 /A 528 ) and pencycuron concentration (2.5-100 μM) with a correlation coefficient (R 2 ) of 0.9915. The detection limit was calculated to be 0.42 μM, which was much lower than that of other analytical methods. The designed ATT-AuNP serves as a promising nanosensor for the rapid, simple, and selective label-free colorimetric detection of pencycuron in rice, potato, cabbage, and water samples, is highly sensitive, and does not require sophisticated instruments, tedious sample preparations, and time-consuming separation and pre-concentration procedures., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Photothermal therapy (PTT) is performed using near-infrared-responsive agents, which is proven to be an effective therapeutic strategy against cancer with several advantages including minimal invasion, high effectiveness, and easy implementation. Herein, we report a facile and novel one-pot synthetic approach for the fabrication of polydopamine-folate carbon dots (PFCDs) as theranostic nanocarriers for the image-guided PTT targeting of prostate cancer (PCa) cells that express a prostate-specific membrane antigen (PSMA) (folate hydrolase 1). The as-fabricated PFCDs exhibited several advantages such as easy preparation, high biocompatibility, low toxicity, good water-solubility, and excellent photothermal effect with robust blue fluorescence emission. The PSMA-directed imaging of PCa using PFCDs showed remarkable fluorescence enhancement in LNCap cells as compared to the case of other cells that did not express PSMA. PFCDs exhibited a photothermal effect in the PCa cells when irradiated with an 808 nm laser, which possibly resulted in the complete elimination of the tumor. Thus, these features make PFCDs a promising candidate for PTT. Moreover, PFCD-based PTT provides an effective biomedical platform for cancer therapy.