Facile synthesis of silver decorated biochar as a novel and highly active biosourced anti-kinetoplastid agent

Neglected tropical diseases include Chagas disease, also known as American Trypanosomiasis and leishmaniasis remain a serious health problem in several endemic. To address this medical problem, much has been done in the past 15 years, to design nanomaterials with effective anti-kinetoplastid activity, particularly those nanomaterials based on gold and silver nanoparticles. Herein, we describe a simple method to prepare silver-loaded biochar by pyrolysis of silver nitrate-impregnated agrowaste powder (from olive stones). The resulting Biochar@Ag was prepared at 400 ?C for 15 min, and the yield was found to be 36.5 %. The supported metallic Ag nanoparticles have triangular shape in the nanoscale regime (< 100 nm) and a loading of 7.85 mmol per gram of Biochar@Ag. The Biochar@Ag showed highly promising antiparasitic activity against promastigotes stage of L. donovani, L. amazonensis and epimastigotes of T. cruzi with an IC(50 )of 9.942 +/- 0.900 ppm; 14.555 +/- 1.035 ppm and 12.154 +/- 0.206 ppm, respectively. From the above, this work conclusively demonstrates that slow pyrolysis is a unique thermochemical approach to valorize agrowastes into highly effective anti-kinetoplastid silver-loaded biochar with remarkably low cytotoxicity towards murine macrophages.

Automated summary

This study describes a simple method to prepare silver-loaded biochar and demonstrates its highly effective antiparasitic activity against certain tropical diseases. The method has the potential to convert agricultural waste into effective nanomaterials for tropical disease treatment.