Agri-biomass derived lignin is one of the most abundant natural nontoxic organic polymers. However, a major portion of lignin is underutilized, which is being left in the fields or thrown into rivers, causing waste accumulation. Utilization of the low-cost biomass-derived lignin serves a dual purpose by reducing agri-waste and by converting it into value-added materials. Here we describe the valorization of agri-biomass based lignin via its direct utilization in the green and one-step synthesis of zinc oxide nanocomposites. Lignin offered an easy and sustainable synthesis of nanocomposites in a water–ethanol mixture without the need to use any toxic material. The lignin derived nanomaterials showed excellent potential as antioxidant, UV-blocking and antimicrobial agents due to the synergistic effect of lignin and zinc oxide. Further, these nanocomposites were incorporated as an additive into a commonly used body cream to impart UV-blocking and antimicrobial properties. This one-step, cost-effective and green synthesis technique of lignin derived zinc oxide nanocomposites not only contributes to agro-waste reduction, but at the same time helps in the production of value-added materials.

The emergence of carbon nanotubes (CNTs) in the past decade has greatly promoted the development of biosensors, which provide a possible alternative to conventional detection systems.