Certain nano-materials are known to have plant growth promoting effects, which could find applications in agriculture. We drew inspiration from the nano-factories of deep-sea hydrothermal vents; where iron pyrite nanoparticles serve as fertilizer to sustain chemoautotrophic life forms. We synthesized such iron pyrite nanoparticles in a controlled environment and used them as seed treatment agent (Pro-fertilizer). For us, the term ‘pro-fertilizers’ represents those materials that cause enhanced plant growth with minimum interference to the soil ecosystem when used for seed treatment. We conducted multi-location field trials on spinach crops, since it is a globally popular crop, consumed as both fresh (salads) and processed food. The spinach seeds were treated for 14 hours in an aqueous suspension of iron pyrite nanoparticle (FeS₂ + H₂O) and thereafter directly sown in the field setup for the experiment. The control seeds were only treated in water for the same duration and sown directly in the field. After 50 days, the crop yields from iron-pyrite nanoparticle treated seeds and control seeds were evaluated. The plants developed from iron pyrite nanoparticle treated seeds exhibited significantly broader leaf morphology, larger leaf numbers, increased biomass; along with higher concentration of calcium, manganese and zinc in the leaves when compared to the plants developed from control seeds. We further investigated the possible mechanism resulting in the biomass enhancement following seed-treatment. Our results indicate that there is an enhanced breakdown of stored starch in the iron pyrite treated seeds resulting in significantly better growth. This raises the possibility of developing iron pyrite nanoparticles as a commercial seed-treatment agent (pro-fertilizer) for spinach crops.

Silk cocoon membrane (SCM) is an insect engineered structure. We studied the electrical properties of mulberry (Bombyx mori) and non-mulberry (Tussar, Antheraea mylitta) SCM. When dry, SCM behaves like an insulator. On absorbing moisture, it generates electrical current, which is modulated by temperature. The current flowing across the SCM is possibly ionic and protonic in nature. We exploited the electrical properties of SCM to develop simple energy harvesting devices, which could operate low power electronic systems. Based on our findings, we propose that the temperature and humidity dependent electrical properties of the SCM could find applications in battery technology, bio-sensor, humidity sensor, steam engines and waste heat management.

Fluorophores are ubiquitous in nature. Naturally occurring fluorophores are exceptionally stable and have high quantum yield. Several natural systems have acquired fluorescent signature due to the presence of these fluorophores. Systematic attempt to harvest these fluorophores from natural systems could reap rich commercial benefit to bio-imaging industry. Silk cocoon biomaterial is one such example of natural system, which has acquired a fluorescent signature. The objective of this study is to develop simple, rapid, commercially viable technique to isolate silk cocoon membrane fluorophores and exploring the possibility of using them as fluorescent dye in bio-imaging. Here, we report an innovative water glass (Na₂SiO₃) based strategy to isolate the silk cocoon fluorophores. Isolated fluorophore is majorly quercetin derivatives and exhibited remarkable photo- and heat stability. Fluorescence and mass spectrometric analysis confirmed presence of a quercetin derivative. We further used this fluorophore to successfully label the silicate shell of diatom species Nitzschia palea.

Sustainable charge storage devices require materials that are environmentally benign, readily moldable, easily synthesizable, and profitable for applications in the electronics industry. Nano iron pyrite (FeS₂) is one such material, which is applicable in diverse areas like photovoltaic devices to seed dressing in agriculture. In this work, we propose an innovative application of nano FeS₂viz., as a symmetric charge storage device that is flexible, portable, and lightweight; along with its fabrication details. The device consists of a (H₃PO₄)/polyvinyl alcohol (PVA) electrolyte gel sandwiched between two similar electrodes made up of FeS₂/poly-aniline (PA), upon which graphite sheets are used as current collectors. Electrodes were characterized by XRD, FTIR and SEM. The device was calibrated by cyclic voltammetry and charge–discharge cycle. In its present laboratory prototype form, it powers solid-state electronic devices and electric motors. Further refinements of this device will open up new avenues in the field of sustainable charge storage devices and low power electronics.