Sardar Bahadur Khan Women's University

Quantitative chemical analyses using vibrational spectroscopic tools such as surface-enhanced Raman scattering (SERS) is widely known due to its ultra-sensitive label free detection, yet its wide spread application is hindered by challenges in developing substrates that are simultaneously sensitive, stable, cost-effective, and reproducible. To address the limitations of traditional plasmonic nanoparticles, such as aggregation and poor oxidation resistance, we designed a sustainable hybrid SERS sensor by integrating silver/silver chloride (Ag/AgCl) heterostructures onto a sustainable cellulose support (C/Ag/AgCl) obtained from biowaste. This design leverages the synergistic effects of strong electromagnetic enhancement from Ag via localized surface plasmon resonance and chemical enhancement via AgCl through charge transfer and separation. The hybrid sensor exhibited 90 days stability and high uniformity. The SERS performance of C/Ag/AgCl sensor was validated through detection of Crystal Violet (CV), Sudan-I (SD) and Malachite Green (MG) in spiked lake water samples, achieving ultra-low limits of detection of 10 pM, 100 pM and 10 pM, respectively. The corresponding enhancement factors were calculated to be 2.6 x 106, 1.0 x 106 and 9.4 x 106, for CV, SD, and MG, respectively. The adsorption was effectively quantified through Freundlich isotherm model, which showed high non-linear correlation coefficients of 0.952, 0.931 and 0.956 for CV, SD and MG. This study establishes a simple, ecofriendly synthesis route for a versatile synergistically enhanced high-performance SERS sensor, paving the way for its quantitative application in monitoring hazardous pollutants at critically low concentrations.

Raisins are extensively consumed functional foods; however, their nutritional characteristics vary significantly due to differences in grape variety, region, and environmental conditions. The present study aimed to evaluate six locally produced raisin varieties Sundar Khani, Sahibi, Kishmishi, Haita, Tour, and Pahari through proximate analysis, phytochemical composition, and elemental profiling to determine their nutritional potential. Standard analytical methods were used, and data were statistically analyzed using ANOVA, Tukey's test, PCA, and cluster analysis to determine significant differences among varieties. The results revealed considerable differences in macronutrients, phenolic and flavonoid content, and mineral concentrations. Proximate analysis revealed that Tour raisins contained the highest amount of moisture content (4.40%) and protein content (3.24%). Kishmishi had the highest level of ash content (2.08%) and fat content (1.92%); likewise, Pahari had the highest amount of fat content (1.92%). Pahari had the highest total phenolics, flavonoids, and essential minerals such as zinc (5.46μg/g), iron (101μg/g), calcium (1367μg/g), magnesium (400μg/g). PCA further demonstrated Pahari as the most nutrient-dense variety among the studied varieties. Overall, the findings demonstrate significant varietal differences and highlight Pahari raisins as a promising functional food with strong nutritional characteristics, supporting their potential application in healthy diets and food-related products.

Background: Epidemiological studies have confirmed that longer exposure to insecticides like cypermethrin (GYP) significantly increases the risk of male reproductive toxicity. Crocus sativus L. has been recognized due to its therapeutic properties, but its exact role and molecular mechanisms in treatment of reproductive dysfunction remain unclear. Methods: During this study, 36 rats were randomly divided into six groups (n = 6): control, GYP-induced (60 mg/kg), standard (leuprolide 3 mg/kg) and three treatment groups receiving aqueous, ethanolic, and oil extracts (50 mg/kg or 20 mL/kg) for post-toxicity induction. Results: The finding represented that exposure of GYP significantly increased oxidative stress, disrupted testicular architecture, and markedly reduced testosterone levels (P < 0.05). Importantly, Crocus sativus L. treatment alleviated these changes by increasing the expression of Nrf2 (nuclear factor erythroid 2-related factor 2), restoring the activity of antioxidant enzymes, and enhancing testicular histomorphology. Surprisingly, molecular docking established a high binding affinity of Crocus sativus L. phytoconstituents such as gallic acid, cinnamic acid and quercetin to the Nrf2-Keap1 complex. It is worth noting that, Crocus sativus L. exhibited a high level of protection against reproductive toxicity caused by GYP in male rats, which was mediated by the activation of Nrf2 pathway, reduction of oxidative damage, and favorable ADMET characteristics. Conclusion: Notably, this research provides a more valid, safe, and effective method of developing new drugs for reproductive disorders, however, further investigation is needed to support the research findings and implement it in clinical practice.

Culex mosquitoes are important pathogens carriers to transmit West Nile virus and lymphatic filariasis, so accurate species identification and eco-friendly methods are necessary for proper control measures. The mosquito species (n=2094) collected from 19 different sites across Karachi region, were morphologically segregated intro 3 different genera (Aedes, Anopheles and Culex) by stereomicroscopy, followed by scanning electron microscopy and molecular identification of Culex by PCR. The molecular amplification of PCR product by agarose gel electrophoresis demonstrated a similar to 740 bp COI fragment and further confirmed the Culex species. The green synthesized silver nanoparticles (Ag NPs) using Aloe vera (AV) and Cassia fistula (CF) extracts were characterized by UV-Vis, SEM, EDS and FTIR. AV-Ag NPs were found smaller (approximate to 65-79 nm) than CF-Ag NPs (approximate to 80-95 nm) in size. In the larvicidal bioassay, the mortality of fourth-instar Culex larvae (n=20 / treatment) was recorded at 16, 32, 64 ppm of different NPs treatments, at 24, 48, 72 h post-treatment compared to the controls. AV-Ag NPs showed significantly (p<0.05) greater efficacy (98.30% mortality at 64 ppm at 72 h) than CF-Ag NPs (65.00% at 64 ppm at 72 h). Moreover, the probit regression analysis showed better LC50=17.85 ppm and LC90=42.51 ppm for AV-Ag NPs (72 h) as compared to LC50=36.35 ppm and LC90=361.38 ppm for CF-Ag NPs. Thus, the results demonstrated that Aloe vera-mediated Ag NPs are promising, eco-friendly larvicidal candidate for integrated mosquito control.

Surface-enhanced Raman spectroscopy (SERS) is a promising method for identifying microplastics (MPs). Nonetheless, traditional solid SERS substrate-based detection often struggles with individual MPs, making it particularly difficult to detect multiple MPs simultaneously and in a recyclable manner. To achieve ultrasensitive, multiplex, and easily recyclable SERS detection of MPs in environmental water samples, an in situ construction method was developed to create a particle-in-cavity (PIC) structure. This involved the simultaneous formation of PDMS cavities and the in situ embedding of Ag NPs into these cavities. The PIC structure not only successfully combined "surface hot spots" and "volume hot spots" but also enhanced SERS uniformity and resistance to ultrasonication due to the in situ embedding strategy. The flexible PIC-structured film allowed for the simultaneous SERS detection of three MPs (polystyrene, polypropylene, and polyethylene) in both seawater and tap water, with detection limits (LODs) of 0.1, 0.5, and 0.5 μg/mL, respectively. Recyclable SERS detection of the MPs for five recycles was easily accomplished through ultrasonication cleaning with xylene. Utilizing the SERS spectra of the three MPs, machine learning algorithms enabled precise quantification of the MPs in environmental water. Visual identification was conducted using Raman mapping for the mixture of the three MPs. This detection method, which integrates the unique PIC structure and machine learning, paves the way for future advancements in ultrasensitive and easily recyclable SERS detection for environmental monitoring.