Debashis Panda

Open-field burning of rice straw, an abundant source of renewable biomacromolecules, remains a major environmental and public health concern. Herein, we report an integrated upcycling strategy that simultaneously valorizes rice-straw-derived cellulose and lignin into high-value functional nanomaterials. Microcrystalline cellulose is converted into nanocellulose (NC) and processed into electrospun nanofibers by incorporating rhodamine B (RhB) as a fluorescent dye. The resulting nonwoven fibrous network serves as a dual-mode sensor, selectively detecting CO2 gas over CH4 through its hydroxyl-rich network while modulating rhodamine B fluorescence in the presence of acidic vapors. In parallel, self-assembly of low-density lignin yields lignin nanoparticles (314 ± 66 nm) exhibiting broad-spectrum UV shielding and antioxidant activity (IC50 = 0.25 mg mL−1). Adding just 5 wt % lignin nanoparticles boosts sunscreen sun protection factor (SPF) from 32.5 to 104. Our work demonstrates a multi-product biorefinery approach for biomass valorization into value-added materials for environmental sensing and photoprotection.

NO₂ and NO are among the most hazardous environmental gases, primarily generated from fossil fuel combustion, and power plants, posing a serious challenge for achieving Sustainable Development Goals (SDG 3). Poly(triarylamine) (PTAA), a polymer with a delocalized π-conjugated backbone has been investigated for its efficacy in gas sensing under ambient conditions. Herein, a PTAA thin-film semiconductor gas sensor is fabricated and systematically evaluated for the detection of nitrogen dioxide (NO₂) and nitric oxide (NO) at room temperature. Thin films of PTAA are deposited onto prefabricated interdigitated electrodes (IDEs) by drop-drying a solution of PTAA in chloroform, ensuring straightforward device integration. The structural and morphological features of PTAA are characterized by using spectro-microscopic techniques. The fabricated sensors exhibit clear and reproducible responses of 70.8% and 27.8% toward 5 ppm NO₂ and NO, respectively, supported by repeatability, response, and recovery characteristics. In addition, the PTAA sensor showed the highest NO₂ selectivity when tested against common exhaust pollutants (H₂S, SO₂, NH₃). The response and recovery times toward NO₂ were recorded as 295 s and 505 s, respectively, highlighting superior sensitivity and faster recovery dynamics when compared to NO. These findings establish PTAA as a promising organic semiconductor for the selective detection of NOx gases.

Transparent coiled flow inverters (CFI), which are superior to opaque coil reactors, are hardly explored in performing condensation reactions of organic molecules. Herein, the continuous flow condensation reaction of gallic acid using CFI is reported with a 4 mm internal diameter. The length of the flow reactor is varied by connecting CFIs in series. Real‐time images of reactor captured during flow synthesis resolve the intricacies of reaction dynamics and stages of desired product formation. Stack CFI provides a desired residence time for carrying out reaction at high flow rate. Condensation of gallic acid in dimethyl formamide yields a green emissive xanthene analog. The production of organic emitter is optimized by regulating reactant flow rate and temperature of the reaction. The presence of a vapour–liquid phase boundary enhances the interfacial area, that further contributes to increasing the product yield. The optimized condition for fluorescent product using stack CFI is 190 °C (±5) temperature at 5 mL h ⁻¹ (±0.5) flow rate. A residence time of about 14 h (±1) and a heat flux of 4.46 W m ⁻² (±0.5) are desired for maximizing product yield using stack CFI. These suggest that CFI‐based flow reactor can easily be tailor‐made and economical as well.

Cellulose nanocrystal (CNC) is synthesized from banana trunk due to their easy availability and high abundance. The CNC is functionalized by amine to augment its optoelectronic properties. CNC film has been fabricated by the solution casting method. In this letter, we report free-standing amine-functionalized CNC films as flexible sensors for organic Resistive Breath sensors. The structural characterizations reveal a high degree of crystallinity, 97% for amine-functionalized CNC with a diameter of about 17 nm. The response of the fabricated sensor to mouth breathing is examined under exhalation and inhalation at ambient conditions. Various breathing patterns of a healthy adult are identified, as slow breathing, normal breathing, and rapid breathing. The sensor exhibits an ultrafast response and recovery time of approximately 180 ms, along with good repeatability. In addition, the sensor achieves a high sensitivity of 10.3 μA/% relative humidity, confirming its suitability for humidity-based breath detection applications in wearable and health-monitoring systems.

Ferroptosis has been recognized as an iron-based nonapoptotic-regulated cell death process. In the quest of resisting the unyielding vehemence of triple-negative breast cancer (TNBC), herein we have showcased the ferroptosis-inducing heteroleptic [LIr_cRu], [LIr_cIr_h], and [LIr_cRe] complexes, enabling them to selectively target "sialic acid", an overexpressed cancer cell-surface marker. The open-circuit potential (OCP) measurements in live cancer cells revealed the specific interaction between TNBC and the complexes, whereas control experiments with normal cells did not exhibit such interactions. GSH depletion, GPx4 inhibition, NADH/NADPH oxidation, lipid peroxidation, COX-2 activation, and Nrf2 inactivation were meticulously investigated upon treatment with these complexes to establish a strong basis for ferroptosis. Among all complexes, the complex [LIr_cIr_h] (IC₅₀ = 25 ± 2.17 μM) has been well-documented as a potent ferroptosis inducer, which unveils the sturdy interaction with sialic acid possessing the highest binding constant (K_b = 0.71 × 10⁵ M^-1, ΔG = -279345.8026 kcal/mol) along with the highest serum albumin binding affinity (K_HSA = 0.67 × 10⁶ M^-1) and significant DNA intercalation (K_b = 0.56 × 10⁵ M^-1, K_app = 1.06 × 10⁶ M^-1, and C₅₀ of intercalation is 76.56 μM), displaying the decreased current intensity in differential pulse voltammetry (DPV). Moreover, the complex [LIr_cIr_h] exhibited mitochondrial dysfunction and membrane damage (diminished MMP, ΔΨ_m) through the production of copious reactive oxygen species (ROS) in MDA-MB-231 cells upon considerable accumulation in mitochondria (Pearson's coefficient = 0.842). The analysis of the field emission scanning electron microscopy (FE-SEM) image has marked the vivid membrane damage induced by the complex [LIr_cIr_h], exhibiting ablaze evidence for the destruction of TNBC cells through ferroptosis.