Hygienic coatings with bioactive nano-additives from Senna occidentalis-mediated green synthesis

Abstract

Nowadays urban populations spend 90% of their time in buildings where microbial growth lead to hazardous environments which produce health problems characterized by irritation of the respiratory tract, infections, allergies and asthma. Some research lines seek to obtain antimicrobial materials to prevent such health problems. Green synthesis of different nanoparticles was carried out to explore their antimicrobial potential. Solutions of silver, copper, cerium, lanthanum and zinc salts were used as source of metal ions for the synthesis process. Aqueous plant extract from Senna occidentalis, a small shrub, was used, for the first time, as reducing and stabilizing agent to obtain additives to bioactive coatings. The stable synthesis products were evaluated by UV–vis spectroscopy and their antimicrobial properties were assessed. Other characterizations by transmission electron microscopy and Fourier transformed infrared spectroscopy were also performed. Silver and copper nanoparticles were stable over time. However, only silver nanoparticles showed antibacterial and antifungal activity and were used for obtaining antimicrobial waterborne acrylic paints. The formulation with 25 mg/100 g resulted in efficient inhibition of the fungal and bacterial biofilm.