Exploring sustainable management by using green nano-silver to combat three post-harvest pathogenic fungi in crops.

Global crop protection and food security have become critical issues to achieve the 'Zero Hunger' goal in recent years, as significant crop damage is primarily caused by biotic factors. Applying nanoparticles in agriculture could enhance crop yield. Nano-silver, or AgNPs, have colossal importance in many fields like biomedical, agriculture, and the environment due to their antimicrobial potential. In this context, nano-silver was fabricated by Citrus medica L. (Cm) fruit juice, detected visually and by UV-Vis spectrophotometric analysis. Further, AgNPs were characterized by advanced techniques. UV-Vis spectroscopic analysis revealed absorbance spectra at around 487 nm. The zeta potential measurement value was noted as -23.7 mV. Spectral analysis by FT-IR proved the capping of the acidic groups. In contrast, the XRD analysis showed the Miller indices like the face-centered cubic (fcc) crystalline structure. NTA revealed a mean size of 35 nm for nano-silver with a 2.4 × 108 particles mL-1 concentration. TEM analysis demonstrated spherical Cm-AgNPs with 20-30 nm sizes. The focus of this research was to evaluate the antifungal activity of biogenic AgNPs against post-harvest pathogenic fungi, including Aspergillus niger, A. flavus, and Alternaria alternata. The Cm-AgNPs showed significant antifungal activity in the order of A. niger > A. flavus > A. alternata. The biogenic Cm-AgNPs can be used for the inhibition of toxigenic fungi.

Biogenic Synthesis of Fluorescent Carbon Dots (CDs) and Their Application in Bioimaging of Agricultural Crops.

Fluorescent nanoparticles have a transformative potential for advanced sensors and devices for point-of-need diagnostics and bioimaging, bypassing the technical burden of meeting the assay performance requirements. Carbon dots (CDs) are rapidly emerging carbon-based nanomaterials. Regardless of their fate, they will find increasing applications. In this study, a simple approach for synthesizing CDs from fruit peels was developed. The CDs were fabricated from Annona squamosa (L.) peels using a carbonization technique through microwave-assisted hydrothermal digestion at temperatures around 200 °C. Synthesized CDs were detected using a UV transilluminator for the preliminary confirmation of the presence of fluorescence. UV-Vis spectrophotometry (absorbance at 505 nm) analysis, zeta potential measurement (-20.8 mV), nanoparticles tracking analysis (NTA) (average size: 15.4 nm and mode size: 9.26 nm), photoluminescence, and Fourier transform infrared (FT-IR) analysis were used to identify the capping functional groups on the CDs. The total quantum yield exhibited was 8.93%, and the field emission scanning electron microscopy (FESEM) showed the size range up to 40 nm. The germinating mung bean (Vigna radiata (L.)) seeds were incubated with biogenically synthesized CDs to check the absorption of CDs by them. The fluorescence was observed under a UV-transilluminator in the growing parts of seeds, indicating the absorption of CDs during the germination, development, and growth. These fluorescent CDs could be used as a bioimaging agent. This novel method of synthesizing CDs was found to be eco-friendly, rapid, and cost-effective.

Chitosan nanoparticles (ChNPs): A versatile growth promoter in modern agricultural production.

Agriculture is a backbone of global economy and most of the population relies on this sector for their livelihood. Chitosan as a biodegradable material thus can be explored for in various fields in its nano form to replace non-biodegradable and toxic compounds. The chitosan has appealing properties like biocompatibility, non-toxicity, biodegradability, and low allergenic, making it useful in several applications including in agriculture sector. Because of their unique properties, chitosan nanoparticles (ChNPs) are extensively applied as a bioagent in various biological and biomedical processes, including wastewater treatment, plant growth promoter, fungicidal agent, wound healing, and scaffold for tissue engineering. Furthermore, the biocompatibility of chitosan nanoparticles (ChNPs) is reported to have other biological properties such as anti-cancerous, antifungal, antioxidant activities, even induces an immune response in the plant, and helps manage biotic and abiotic stresses. Chitosan can also find its application in wastewater treatment, hydrating agents in cosmetics, the food industry, paper, and the textile industry as adhesive, drug-delivering agent in medical as well as for bioimaging. Since chitosan has low toxicity, the nano-formulation of chitosan can be used for the controlled release of fertilizers, pesticides, and plant growth promoters in agriculture fields. The ChNPs applications in precision farming being a novel approach in recent developments. Here we have comprehensively reviewed the major points in this review are; the synthesis of ChNPs by biological resources, their modification and formulation for increasing its applicability, their modified types, and the different agricultural applications of ChNPs.

Assessment of in vitro antimicrobial efficacy of biologically synthesized metal nanoparticles against pathogenic bacteria.

The microbial infections due to biofilm forming bacterial pathogens are very common in human subjects. The intensive application of antibiotics in integrated disease management strategy has led to increased multidrug resistance incommon pathogens. Thus, indicating need of developing an alternative method for the control of these multidrug resistant pathogens. Present study involves the Moringa oleifera aqueous extract mediated biological synthesis of silver (Ag nanoparticles (NPs)- Avg. size 82.5 nm; zeta potential = -27.9 mV), copper oxide (CuONPs- Avg. size 61 nm; zeta potential = -19.3 mV), iron oxide (FeONPs- Avg. size 83.3 nm; zeta potential = -9.37 mV) and alumina (AlONPs- Avg. size 87.3 nm; zeta potential = -10.9 mV) nanoparticles. Biological nanoparticles were detected by visual observation, spectrophotometric detection followed by zeta potential analysis, nanoparticle tracking analysis, Fourier transform infrared spectrometry and X-ray diffraction analysis. Nanoparticles were further evaluated for their in vitro antimicrobial potential, membrane damage effectiveness, biofilm inhibition activity by MTT assay. Nanoparticles were assessed against human pathogens viz. two Gram-positive (Bacillus subtilis MTCC 441 and Staphylococcus haemolyticus MTCC 3383) and two Gram-negative bacteria (Enterobacter aerogenes MTCC 111 and Salmonella enterica ser. Typhi MTCC 8767). The nanoparticles exhibited akin activity pattern against all pathogens studied i.e. AgNPs > CuONPs > AlONPs > FeONPs. Tested nanoparticles registered lower MIC values and more intensified growth inhibition against Gram-negative bacteria compared to their Gram-positive counterparts. These results pointed out that the M. oleifera mediated nanoparticles can be prospectivelyutilized in the development of alternative antimicrobials against diverse bacterial infections.

A novel nano-sulphur and essential oil-based room freshener

Introducción: Alternaria spp y Candida spp. son hongos patógenos de ambientes interiores como la casa, la oficina, el aula, etc., causan enfermedades como asma crónica e infecciones sistémicas en individuos inmunodeprimidos a través de la secreción de diversas sustancias tóxicas. Los ambientadores a base de productos químicos disponibles comercialmente que se utilizan para controlar la carga de hongos en el ambiente interior no son beneficiosos para la salud humana. Objetivo: proporcionar una alternativa viable en forma de enfoque basado en nanopartículas para el manejo de hongos transmitidos por el aire. Metodología: aislamiento, identificación microscópica y bioquímica de hongos de interior; Síntesis de nanopartículas de azufre (SNP) mediadas por Azadirachta indica, su detección y caracterización; y evaluación in vitro de SNP contra hongos aislados presentes en el ambiente interior. Resultado: Los hongos aislados se identificaron como especies de Alternaria spp y Candida spp. Los SNP mostraron máximos de absorbancia a 291 nm. El análisis NTA mostró un tamaño medio de 188,4 nm y un potencial zeta de -4,94 mV, lo que representa una síntesis de SNP estables. El patrón XRD confirmó la naturaleza cristalina cúbica centrada en la cara de los SNP. El espectro FTIR representó la presencia de compuestos polihidroxilo, nitrilo, ceto, aromáticos y carboxílicos que estabilizaron los SNP. Los ensayos antifúngicos demostraron la actividad significativa de los SNP formulados y del ambientador infundido con aceite de eucalipto. Conclusión: Los SNP mediados por A. indica se pueden aplicar en la formulación y fabricación de un ambientador ecológico para el manejo de hongos patógenos de interior como Alternaria spp y Candida spp.

Introduction: Alternaria spp. and Candida spp. are the main fungal pathogen of indoor environment like house, office, classroom, etc. These may cause various diseases and infections like systemic infections, or chronic asthma in immunocompromised individuals through secretion of various toxic substances. Chemical-based commercially available room fresheners used to control the fungal load of indoor environment are not beneficial to human health. Objective: was to provide viable alternative in the form of nanoparticle-based approach for the management of air-borne fungi. Methodology: The present study primarily focuses on the isolation, microscopic and biochemical identification of indoor fungi; Azadirachta indica-mediated sulphur nanoparticles (SNPs) synthesis, their detection and characterization; and in vitro assessment of SNPs against isolated fungi present in indoor environment. Result: The isolated fungi were identified as Alternaria spp and Candida spp. The SNPs showed absorbance maxima at 291 nm. NTA analysis showed average size of 188.4 nm, and zeta potential of -4.94 mV which represented synthesis of stable SNPs. XRD pattern confirmed the face centered cubic, crystalline nature of SNPs. FTIR spectrum depicted the presence of polyhydroxyl, nitrile, keto, aromatic and carboxylic compounds which stabilized the SNPs. The antifungal assays demonstrated the significant activity of the formulated SNPs and eucalyptus oil infused air freshener. Conclusion: It can be concluded that A. indica-mediated SNPs can be applied in the formulation and manufacture of an ecofriendly air freshener for the management of indoor fungal pathogens like Alternaria spp. and Candida spp.