*2.1. Materials*

Chemicals used in this study include ciprofloxacin hydrochloride (MP Biomedicals, Santa Ana, CA, USA), zinc nitrate hexahydrate (98%, Sigma Aldrich, USA), trisodium citrate dihydrate (Sigma Aldrich, St. Louis, MO, USA), ferric chloride (Himedia, Mumbai, India), Luria agar and Luria broth (Himedia, Mumbai, India), sodium hydroxide (Merck, Kenilworth, NJ, USA), and hydrochloric acid (35.5%, Merck). All the chemicals were of molecular grade.
