Introduction to the biogenic Ag nanozyme for the control and eradication of microbes and environmental pollutants

Abstract

Nowadays we are in a deep need for resolving environmental problems like synthetic dyes, heavy metals release and antibiotic resistant microbes simultaneously. The emergence of new frontiers of nanomaterials like artificial enzymes can relatively answer and cover these challenges. The green husk of Juglans regia (J. regia); an abundant agro-waste was applied to biosynthesize Ag nanozyme (AgNZ) because they are rich in bioactive molecules that can contribute to the biosynthesis of AgNZ. Once AgNZ was fabricated and characterized, its antimicrobial and antioxidant activities were assayed by the micro-dilution method. The capacities of AgNZ for the colorimetric detection of Hg2+ and photocatalytic degradation of Methyl Orange (MO) were assayed. Based on the results, AgNZ could impede the growth of both Gram-negative (Pseudomonas aeruginosa PAO1) and Gram-positive bacteria (Bacillus subtilis ATCC6633). Additionally, these nanomaterials could inhibit the biofilm formation by Staphylococcus aureus 141 and Pseudomonas aeruginosa 137 with high potential in fabrication of resistant biofilms. In addition, the antibiofilm experiments exhibited this NZ can eradicate the pathogenic biofilms produced by Pseudomonas aeruginosa 137. Dadvar heuristic algorithm for predicting the antioxidant activities was applied to find the IC50 value. The predicted IC50 value by the algorithm was 138.14 μg/mL, which was confirmed by experimental investigation. AgNZ offered a sensitive colorimetric sensor for the detection of Hg2+ with a Limit of Detection (LOD) of 5 μg/mL. This nanomaterial was a relative photocatalyst for the degradation of MO. The combination of all results introduced this AgNz as a multifunctional agent with the vast potentials in resolving environmental and microbial contaminations.