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Fluorescence switching via competitive ESIPT and spirolactam ring opening in a multifunctional rhodamine B probe for selective detection of Cu2+ and OCl?: theoretical insights with anticancer and biosensor activity
A multifunctional ESIPT-based rhodamine-derived probe (BHS) was synthesized and developed as a colorimetric and fluorometric sensor for the selective detection of copper (Cu2+) and hypochlorite (OCl?) in aqueous solutions. Initially, BHS exhibits intense whitish blue fluorescence due to the active excited-state intramolecular proton transfer (ESIPT) mechanism within the molecule. However, upon interaction with Cu2+ and OCl?, noticeable changes in absorption and fluorescence occur, attributed to the inhibition of ESIPT resulting from analyte binding with BHS, leading to spirolactam ring opening. Furthermore, significant Stokes shifts in absorption (?? = 34 nm and 170 nm for Cu2+, and 163 nm for OCl?) and emission (?? = 67 nm for both Cu2+ and OCl?) further confirm this transformation. The spirolactam ring opening is induced by Cu2+ coordination, whereas for OCl?, it is triggered by oxidative cleavage. To explore potential biological applications, fluorescence titration experiments were conducted to study the interactions of the BHS-Cu2+ complex with ct-DNA and the transport protein bovine serum albumin (BSA). Additionally, molecular docking studies were performed to assess these interactions, while DFT calculations were employed to optimize the structures of BHS and its Cu2+ complex. The fluorescence changes of BHS in the presence of Cu2+ and OCl? in biological samples have been examined by the anticancer and biosensor activity of BHS in HCT-116 colorectal cancer cells. 2025 RSC. -
Nature-inspired ?-MnMoO4nanocubes from Arachis hypogaea for next-generation wastewater treatment and organic pollutant catalysis
In this study, bimetallic ?-MnMoO4 nanoparticles (NPs) were successfully synthesized via a one-step solution combustion method using Arachis hypogaea (peanut) seed powder as a green fuel. This eco-friendly route was adopted to explore the adsorption, photocatalytic, and catalytic properties of the resulting NPs. The structural, morphological, and optical characteristics of ?-MnMoO4 NPs were systematically characterized using XRD, FTIR, UV-vis, and PL spectroscopy, SEM, and EDX techniques. Notably, ?-MnMoO4 NPs demonstrated excellent adsorption capability toward methylene blue (MB) dye, achieving a removal efficiency of 86.70%, which was primarily attributed to their negatively charged surface. Moreover, the nanoparticles demonstrated a remarkable photocatalytic activity, achieving 81.55% degradation of MB through the photo-oxidation of water into hydroxyl (?H) radicals by photogenerated holes. Beyond dye remediation, the study further explored the catalytic capabilities of o-phenylenediamine via oxidative condensation with substituted aromatic aldehydes to synthesize benzimidazole derivatives, achieving yields ranging from 35% to 85%, depending on the substituents used. This integrated approach highlights the potential of ?-MnMoO4 NPs not only in pollutant removal but also in facilitating the green synthesis of high-value chemical products, demonstrating promising applications in environmental remediation and fine chemical industries. This journal is The Royal Society of Chemistry, 2026 -
Sustainable fabrication of arecanut waste-based polymer blend adsorbents for enhanced lead(ii) ion removal from water
Heavy metal contamination in water systems leads to critical environmental and health challenges, necessitating sustainable remediation technologies. This study presents a unique approach utilising arecanut organic residue, an abundant agricultural waste, for the removal of lead from water. A bioadsorbent composite film was synthesised using chitosanpolyvinyl alcohol (PVA) incorporated with arecanut organic residue by solvent casting. The physicochemical properties of the films were characterised by XRD, FTIR, optical profilometry, BET surface area and SEM analyses. The adsorption efficiency of the synthesised films was tested by examining the removal of Pb(ii) from water. The bioadsorbent films demonstrated a Pb(ii) removal efficiency of 94.6% from 5 ppm solutions at pH 6 within 60 minutes at 70 C using 0.5 g of the film. Optimisation studies revealed the critical role of functional group availability and film porosity of the polymer blends, along with experimental conditions that enhanced the adsorption capacity. Kinetic studies also confirmed the results obtained from the optimisation studies. The adsorption kinetics followed a pseudo-second-order model, and isotherm analysis confirmed Langmuir-type adsorption. The sustainable bioadsorbent exhibited good reusability, maintaining performance over multiple cycles. This journal is The Royal Society of Chemistry, 2026 -
Biomass-derived carbon supported cobalt-phospho-boride as a bifunctional electrocatalyst for enhanced alkaline water splitting
Developing efficient and low-cost bifunctional electrocatalysts for overall water splitting in order to reduce the future energy crisis is crucial and challenging. Herein, a facile two-step fabrication via pyrolysis and chemical reduction was used for the synthesis of biomass-derived carbon-based electrocatalyst (MT) from mulberry bark and its subsequent modification with cobalt phospho-boride (MT/CoPB) for efficient bifunctional electrocatalysis in alkaline media. The effect of B/P ratios and carbon-to-metal ratios on electrocatalytic performance of HER was investigated. Notably, the optimized MT/CoPB catalyst (B/P = 5, C : M = 2 : 1) exhibited a lower overpotential of ?86 mV for HER and 310 mV for OER to reach the current density of 10 mA cm?2. The robust electrocatalytic performance of MT/CoPB towards the HER and OER was attributed to the combined effect of carbon and CoPB. Notably, it achieved a low cell voltage of 1.59 V to reach a current density of 10 mA cm?2, also maintaining reliable long-term stability. Characterization studies revealed that the enhanced performance was due to the amorphous structure of the catalyst, high electrochemical surface area, and efficient charge transfer. This work demonstrates the potential of biomass-derived carbon-based materials in the development of cost-effective and durable electrocatalysts for water splitting and green hydrogen production. 2025 RSC. -
CuNi-PTC metal-organic framework: unveiling pseudocapacitive energy storage and water splitting capabilities
Metal-organic frameworks (MOFs), owing to their distinctive structural properties and customizable functionalities, have been garnering significant attention in the pursuit of advanced energy storage and conversion technologies. In this work, a bimetallic MOF, CuNi-PTC, has been synthesized through a straightforward method. Investigations reveal its potential as a high-performance electrode material for supercapacitors and as an electrocatalyst for water splitting. The CuNi-PTC MOF features a large specific surface area, hierarchical porosity, and strong structural stability, as evidenced by spectroscopic and electron microscopy analyses. As a supercapacitor electrode material, CuNi-PTC delivers an impressive specific capacitance of 1066.24 F g?1 at a current density of 1 A g?1, along with excellent cycling stability, retaining 94% of its capacity after 5000 charge-discharge cycles. Additionally, the electrocatalytic performance of CuNi-PTC for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) was assessed, showing overpotentials of 212 mV for the HER and 380 mV for the OER at a current density of 10 mA cm?2, along with exceptional long-term durability. 2025 RSC. -
Advanced electrochemical detection and profiling of the antihypertensive drug atenolol via a SPION-activated carbon nanocomposite interface
This study reports the synthesis of superparamagnetic iron oxide nanoparticles (SPIONs), activated carbon (AC) and SPION-AC nanocomposites using a simple hydrothermal method. Characterization of the synthesized materials includes dynamic light scattering, X-ray diffraction, field emission scanning electron microscopy, high resolution transmission electron microscopy, and vibrating sample magnetometry, along with electrochemical characterization studies such as electrochemical impedance spectroscopy. Among the SPION-AC nanocomposites, SPION-15%AC was employed to modify a glassy carbon electrode (GCE). The synergistic interaction between SPION and AC significantly enhanced the electrochemical properties of the system, leading to the development of a highly efficient platform for the detection of the antihypertensive drug atenolol (ATN) in commercial tablet samples. The sensor demonstrated excellent performance, with a linear detection range from 1.21 ?M to 285 ?M. With a low detection limit (LOD) of 0.401 ?M, the sensor offers precise quantification of ATN, making it a promising tool for improving patient care. High selectivity, reproducibility, and excellent recovery in complex pharmaceutical matrices further highlight the potential of this sensor for biomedical and clinical applications. 2025 RSC. -
Exploring a GE/Nafion/Co-MOF nanosheets/CuO NPs/GOx powered electrochemical biosensor for ultrasensitive detection of rebaudioside A
Rebaudioside A (Reb A) is a natural, non-nutritive sweetener highly prevalent in the global sweetener market and widely preferred by consumers. In this study, an advanced electrochemical biosensor was developed for sensing Reb A, using a modified graphite rod electrode extracted from discharged ZnC batteries. The electrode was fabricated using a layer-by-layer strategy with Nafion, Co-MOF nanosheets, CuO NPs, and glucose oxidase (GOx) enzyme. The nanomaterials were characterized by UV-vis, FTIR, DLS, zeta potential measurements, XRD, Raman, SEM, TEM, EDS, and XPS techniques. Electrochemical characterization via Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) revealed a significant enhancement in electrical conductivity and increased electroactive surface area. The designed biosensor exhibited a sharp oxidation peak at 0.16 V due to ester bond cleavage in Reb A, which was further amplified in the presence of GOx, resulting from hydroxyl oxidation and hydrogen peroxide generation. Differential pulse voltammetry (DPV) demonstrated a linear response over a concentration range of 2.014 M (R2 = 0.993) with a limit of detection (LOD) of 0.23 M. The sensor displayed excellent analytical performance, with repeatability, reproducibility (RSD = 3.9%), and stability. Additionally, recovery studies confirmed its accuracy, ranging from 97% to 98.17%. Further, the molecular docking studies confirmed strong Reb AGOx interactions (?7.26 kcal mol?1), supporting the biosensor's specificity. The developed biosensor demonstrates excellent analytical performance, making it highly suitable for routine laboratory analysis of sweeteners in complex food matrices. This journal is The Royal Society of Chemistry, 2026 -
Hierarchically porous RhB-encapsulated ZIF-7 as a dual-emission fluorescence probe for ultrasensitive detection of melamine in infant formulations
Melamine is an unauthorized food additive and a highly concerning adulterant in foods that can occur either accidently or intentionally in dairy products, with potential health risks upon exposure to higher concentrations. An ultrasensitive fluorescent probe based on dual emissive RhBx@ZIF-7 was developed to detect melamine. In this study, a fluorescent dye, Rhodamine B (RhB), was successfully encapsulated into the metal-organic framework (MOF) pores of ZIF-7 to form a fluorescent probe (RhB30@ZIF-7), with dual emission properties to enable the detection of melamine at low concentrations. RhB30@ZIF-7 was optimized by varying experimental parameters, including temperature (25 C), pH (7.0), incubation time (10 min), and probe concentration (1 mg mL?1), to enhance its sensitivity and selectivity. The observed fluorescent quenching towards melamine was primarily attributed to the mechanisms of the internal filtering effect (IFE), due to absorption of the excitation wavelength by melamine, causing a turn-off response in the system. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.47 ?M and 1.4 ?M, respectively, with an R2 of 0.99. This study reveals the previously unexplored enhanced fluorescence of RhB30@ZIF-7 and elucidates the contribution of the intermolecular interaction between RhB and ZIF-7 to fluorescence sensing, paving the way for food safety monitoring. 2025 RSC. -
Ethylenediamine modified carbon nanospheres from biomass for selective membrane filtration
The present work investigates the antifouling properties dye and antibiotic removal efficiency of PVDF/E-CNS membranes. Carbon nanospheres (CNS) derived from rice husk (RH) were pyrolyzed at 800 C. Further, ethylenediamine functionalized carbon nanospheres (E-CNS) were obtained via in situ decoration of ethylenediamine on acid-functionalized carbon nanospheres (O-CNS). The synthesized E-CNS were characterized by techniques such as XRD, FESEM, Raman spectroscopy, FTIR and BET. The membranes were fabricated by integrating E-CNS at varying loadings (0.10.7 wt%) via a non-solvent induced phase separation (NIPS) technique. The membrane properties were assessed through FESEM, water contact angle measurements, pure water flux, antifouling studies and membrane rejections. In comparison to the other developed membranes, PVDF-2 with 0.3 wt% E-CNS loading displayed optimal performance, pure water flux (PWF) of ?318.90 L m?2 h?1, flux recovery ratio (FRR) > 90% up to three cycles, improved contact angle (80.24 to 68.44) and reduced roughness. Furthermore, PVDF-2 achieved dye rejection of methyl orange (MO 93.2%) and rhodamine B (RB 94.6%), and antibiotic rejection of amoxicillin (AM 93.8%) and tetracycline (TC 94.1%), respectively. These findings demonstrate the integration of E-CNS derived from a bio-source, making them a promising additive to improve PVDF membrane performance. This journal is The Royal Society of Chemistry -
Unveiling the supercapacitive behavior of electrospun Cr2CTx/carbon nanofiber membrane
A novel electrospinning-based strategy was employed to fabricate Cr2CTx/carbon nanofibers using Cr2CTx MXene and polyvinyl alcohol (PVA) as precursors. This approach enables the formation of porous, conductive composite MXene layers dispersed in carbon nanofibers. The resulting material exhibited notable supercapacitive performance, delivering 338.8 F g?1 capacitance, 67.7 Wh kg?1 energy, and 1998 W kg?1 power density. This journal is The Royal Society of Chemistry, 2025 -
Ion-imprinted carbon dots: rationally designed fluorescent probes for the detection of selected metal ions from aqueous solutions
Photoluminescence properties of Carbon Dots (CDs) have been leveraged for their use as sensors for a variety of analytes, including inorganic ions, organic molecules, and biomolecules. The selective fluorescence response of CDs to specific analytes is generally not pre-designed. Rationally designed synthesis of CDs with pre-defined selectivity to specific analytes is a less explored avenue. This study presents a novel method for the customized synthesis of CD fluorescent probes and an ion-imprinting-based selective detection of metal ions using these CDs. Poly(sodium 4-styrenesulfonate) [PSS] treated with Cd(ii) ions was used as the precursor for preparing Cd-imprinted CDs, and a modified form of these CDs was used for the sensing of Cd(ii) in aqueous solutions. As synthesized CDs have Cd(ii) ions on their surface, which were subsequently removed through appropriate chemical treatment. This removal results in binding sites of Cd(ii) ions on the CDs. Formation of such binding sites results in alterations of the fluorescence of CDs. Exposure of these particles to analytes containing Cd(ii) ions leads to the re-occupation of the binding sites by the metal ions, resulting in a distinct fluorescence response, which serves as the sensing readout. Effectiveness of this ion-imprinting approach is demonstrated by the selective and sensitive fluorescence response of the CDs towards Cd(ii) ions, with a limit of detection (LOD) of 3.62 nM. This strategy of Cd(ii) detection using ion-imprinted CDs represents a novel effort in CD-based sensors, and this can be extended to the sensing of other cations also. This journal is The Royal Society of Chemistry, 2025 -
Fluorescent nanocellulose derived from Plectranthus barbatus for the selective detection of Pb(ii) ions in aqueous solutions
This study reports the synthesis of fluorescent nanocellulose from Plectranthus barbatus and its effective use as a fluorescent probe for the detection of Pb(ii) ions in aqueous solutions. Nanocellulose, a nanoscale derivative of cellulose, is used in a variety of applications, such as sensing, food packaging, and biomedical applications, owing to its characteristic properties. In sensing applications, it is mostly used as a support or substrate for the sensing probe. Nanocellulose shows intrinsic fluorescence, which can be harnessed for sensing applications. This underexplored research domain holds significant potential for developing sustainable and cost-effective sensing materials. We synthesized nanocellulose from Plectranthus barbatus (PBNC) and employed it as a fluorescent probe for the detection of Pb(ii). To the best of our knowledge, this is the first report demonstrating the potential of fluorescent nanocellulose for metal ion detection. The properties of fluorescent nanocellulose, PBNC, were studied using Fourier Transform Infrared (FTIR) spectroscopy, X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and Photoluminescence (PL) spectroscopy. The fluorescence intensity of the nanocellulose was remarkably quenched in the presence of Pb(ii) ions selectively. The detection limit (LOD) of Pb(ii) using PBNC was found to be 2.7 nM. PBNC is a novel autofluorescent material that functions as an efficient nanosensor for the detection of Pb(ii) ions, and its applications can be extended to bio-imaging and sensing in biological, chemical, and environmental samples. This journal is The Royal Society of Chemistry, 2026. -
Nanocellulose from coconut midrib used for antibacterial and electromagnetic interference shielding applications
Midrib of coconut (Cocos nucifera) is a natural source of cellulose, which is renewable and biodegradable. The use of natural cellulose for practical applications exemplifies a sustainable reuse of agricultural waste. This work presents the preparation of nanocellulose from coconut midrib using optimized pretreatment and acid hydrolysis processes. The resulting nanocellulose was characterized through various analyses to confirm the morphology and composition. Nanocellulose thus synthesized was used for preparing cellulose nanopaper. In order to improve the water resistance of the cellulose nanopaper, we used a simple approach of functionalization by impregnating it with chitosan (CS), followed by in situ polymerization of polypyrrole (PPy) in the matrix. The functionalized cellulose nanopaper shows good electrical conductivity and an electromagnetic interference (EMI) shielding effectiveness of 21.92 dB at 10 GHz, which makes it a potential material for EMI shielding applications. In addition, the functionalized cellulose nanopaper exhibits bacterial reductions of 93.47% and 82.79% towards Staphylococcus aureus and Escherichia coli, respectively. This work provides a facile and efficient method for the synthesis of nanocellulose from coconut midrib and a useful approach to functionalize cellulose nanopaper. Cellulose nanopapers thus prepared were demonstrated to have applications in EMI shielding and antibacterial coating. 2025 The Royal Society of Chemistry. -
Mechanistic elucidation of irreversible chemodosimetric sensing of hydrazine through structural, computational, and bioimaging analyses
A fluorescent chemodosimeter, DBA, has been developed for the selective detection of hydrazine via an irreversible reaction pathway that leads to fluorescence enhancement. The crystal structure of the ligand has been successfully determined. The sensing mechanism involves the conversion of a hydrazide derivative into a hydrazone derivative, as confirmed by both 1H NMR and mass spectrometry. Upon interaction of DBA with hydrazine, the probe exhibits a significant decrease in absorbance at 366 nm and 279 nm, along with a three fold enhancement in fluorescence intensity at 423 nm, achieving a detection limit of 0.37 M. The detection mechanism has also been supported by theoretical analysis using density functional theory (DFT) calculations. For practical applications, DBA has been employed in plant-based cell imaging to monitor hydrazine accumulation in Lathyrus sativus L. (grass pea). Overall, DBA is a simple, effective, and promising fluorescent probe for hydrazine detection in diverse fields such as environmental monitoring, food safety, and biological risk assessment. This journal is The Royal Society of Chemistry and the Centre National de la Recherche Scientifique, 2026 -
Strain-induced wave energy harvesting using atomically thin chromiteen
Developing non-corrosive wave energy harvesters is one of the critical technologies required for sustainable energy harvesting. This work studies the effect of surface defects in atomically thin chromiteen for harvesting energy from water waves. An external strain further enhances the surface charge properties of the chromiteen, resulting in higher electrical output in the fabricated flexible nanogenerator (C-FNG) to harvest wave energy. The peak output voltage of the C-FNG device was ?5 V due to the water wave force. The density functional theory (DFT) results indicate the presence of surface defects in the 2D chromiteen, and the applied strain gradient introduced a redistribution of electron density, possibly due to altered bond lengths in the material. The present work provides an atomistic study of energy harvesting in the marine environment to provide power for deep-sea divers, ships, and any other small electronic sensors or marine Internet of Things in remote areas. This journal is The Royal Society of Chemistry, 2025 -
Onion peel derived carbon nanoparticles incorporated polysulfone membranes: enhanced dye removal from water
The ongoing discharge of hazardous dyes from industrial processes has intensified global water pollution, posing serious threats to aquatic ecosystems and human health. Addressing this challenge, our study explores the potential of bio-based carbon nanomaterials (CNM), synthesized from onion peel biowaste and designated as ON11, as effective agents in dye removal. These CNMs were incorporated into a mixed matrix membrane (MMM), using polysulfone (PSU) as the membrane substrate, to enhance dye adsorption. The CNM synthesis was achieved through a simple, eco-friendly process. We examined their impact on adsorption efficiency by introducing ON11 nanoparticles at varying concentrations into the PSU membrane (ON11@PSU). This CNM-embedded membrane structure offers a solution to challenges associated with the large-scale application of nanomaterials, particularly by minimizing leaching into water and improving durability. The ON11 and ON11@PSU membranes were characterized using various techniques, including SEM, Raman spectroscopy, XRD, optical profilometer, and FTIR, to confirm their behavior, morphology, and structural integrity. The surface area of ON11 was 423.26 m2 g?1, with BJH average pore diameter of 4.5 nm and BET pore volume of 0.26 cm3 g?1. ON11 nanoparticles were adsorptive in nature, and their utility in membrane adsorption is explored. The influence of parameters, including contact time, dye concentration, membrane thickness, pH, and adsorbent dosage, was systematically evaluated to optimize the dye adsorption efficiency of the ON11@PSU membrane pad. It was observed that the thickness of the 60 ?m membrane (Sa = 2.170 ?m and Sq = 2.75 ?m) showed higher removal efficiency for all the selected dyes than the other thicknesses at the native pH itself. The MMM demonstrated its effectiveness as an adsorbent membrane, achieving maximum removal efficiencies of approximately 98% for MG dye, 92% for RhB dye, and 67% for MB dye. The negative zeta potential of adsorptive membranes enabled the electrostatic attraction of positively charged dyes, enhancing adsorption capacity. The findings contribute to developing sustainable and effective membrane utility as adsorbents, opening avenues for the effective use of agricultural waste products in environmental remediation applications. 2025 The Royal Society of Chemistry. -
Turning mango kernel waste into high-energy porous carbon: a sustainable electrode material for high-performance supercapacitors with exceptional stability
This study explores the sustainable production of high-performance supercapacitor electrodes from waste mango kernels, addressing the growing need for eco-friendly energy storage solutions. Porous carbon materials were synthesized via pyrolysis at varying temperatures (700, 800, 900, and 1000 C), designated as MK7, MK8, MK9, and MK10, respectively. The synthesized carbon was obtained via a simple and eco-friendly carbonization, yielding a highly porous structure with a large specific surface area of 1348.9 m2 g?1, for MK9 material as confirmed by BET analysis. Raman spectroscopy revealed a high degree of graphitization with D and G bands, indicating the presence of both disordered and graphitic carbon domains. SEM imaging showed a well-developed, interconnected porous morphology, while XRD patterns confirmed the amorphous nature with partially crystalline domains. The resulting carbon materials were evaluated for their electrochemical performance in supercapacitor applications. Electrochemical characterization revealed that the MK9 sample, pyrolyzed at 900 C, exhibited the highest specific capacitance of 205.8 F g?1, surpassing the performance of the other samples. To optimize device performance, symmetric supercapacitors were fabricated using a CR2032 coin cell configuration with different electrolytes and concentrations. The KOH electrolyte device demonstrated a maximum power density of 5137.86 W kg?1, an energy density of 12.32 W h kg?1, and a specific capacitance of 112.4 F g?1. Furthermore, this device exhibited excellent cycling stability, maintaining its performance over 100 000 galvanostatic charge-discharge cycles. A practical demonstration showed the ability of the device to power a red LED for approximately 15 minutes. These results highlight the potential of utilizing waste biomass, specifically mango kernels, for sustainable and efficient supercapacitor development. 2025 The Royal Society of Chemistry. -
Transforming invasive weeds into energy solutions: water hyacinth-based hybrid electrodes for green supercapacitors
The excessive proliferation of Eichhornia crassipes (water hyacinth) poses significant environmental challenges; however, its abundant biomass offers a sustainable solution for energy storage applications. This study presents an eco-friendly approach to fabricating high-performance supercapacitor electrodes using water hyacinth-derived activated carbon (WH), polypyrrole (PPy), and titanium dioxide (TiO2). The WH-TiO2/PPy hybrid electrode was synthesized via hydrothermal treatment and interfacial polymerization, ensuring a resource-efficient and environmentally responsible process. The composite exhibited a high gravimetric capacitance of 610 F g?1 at 0.5 A g?1 in 3 M KOH, with excellent cycling stability (94% retention after 5000 cycles). An asymmetric supercapacitor with WH-TiO2/PPy as the positive electrode and activated carbon as the negative electrode delivered an energy density of 98 W h kg?1 and a power density of 5606 W kg?1. This work highlights the potential of transforming invasive biomass into cost-effective, high-performance energy storage materials, advancing the principles of green chemistry through waste valorization and sustainable material design. 2025 The Royal Society of Chemistry. -
Laccase-immobilized biochar as a unique host matrix for electrochemical detection of gallic acid: a sustainable engineering approach
An electrochemical platform for the detection of organic persistent polyphenolic pollutant, gallic acid (GA), was fabricated using an enzyme-immobilization approach over acid-functionalized biochar (f-BC) modified carbon fiber electrode (CFP) electrode. The f-BC was synthesized from dried pineapple leaves and was characterised using X-ray diffraction analysis (XRD), Raman spectroscopy, scanning electron microscopy (SEM), Fourier Transform-Infrared Spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) for analysing the physicochemical characteristics. The SEM image of Lac/f-BC/CFP confirmed the presence of a porous and granulated surface upon laccase immobilization, while the FTIR spectrum confirmed the presence of C 00000000 00000000 00000000 00000000 11111111 00000000 11111111 00000000 00000000 00000000 O stretch and N-H bend, indicating amide bond formation. The acid treatment of biochar introduced -OH and -COOH groups that further aided in the successful immobilization of laccase via covalent bonding. The fabricated electrode could demonstrate a linear response within the concentration range of 0.012-40 ?M and a low detection limit (LOD) of 9 nM with high selectivity. The fabricated electrode also showcased high practical utility as it could attain high recovery percentage during real sample analysis in tap, pond, sewage and industrial effluent samples. 2025 The Royal Society of Chemistry. -
Lanthanide-based coordination polymers: a fluorometric Frontier in explosive sensing
In the pursuit of public safety, environmental protection, and counter-terrorism, significant advancements have been made in explosive detection techniques. However, challenges such as limited sensitivity, poor selectivity, and high operational costs remain, particularly for trace-level detection. In this study, we present a simple and scalable synthesis of lanthanide-based coordination polymers (Ln-COPs), denoted as Ho(DAB) and Tb(DAB), formed through the coordination of Ho(iii) and Tb(iii) ions, respectively, with the organic linker 3,3?-diaminobenzidine (DAB). Spectroscopic and electron microscopic analyses confirm their two-dimensional planar structure, resulting from the self-assembly of infinitely long polymeric strands. These luminescent Ln-COPs demonstrate exceptional performance as sensors for detecting both nitroaromatic and non-nitroaromatic explosives via fluorescence quenching. Notably, Tb(DAB) exhibits a remarkable limit of detection of 7.7 M for TNP. Furthermore, mechanistic insights into the quenching process are explored. These results underscore the sensitivity and practical applicability of Ln-COPs in advanced explosive detection systems. This journal is The Royal Society of Chemistry, 2025