Ion selectivity, antioxidant, and antimicrobial properties of fluorescent chitosan-ZIF-8 structure bearing 1,8-naphthalimide

Chromium hexavalent ion (Cr6+) is a highly pollutant for the environment and the development of methods that can detect this ion in a simple way is of critical importance. Here, a fluorescent material (C-Nap) was synthesized by interacting chitosan with 4-sulfo-1,8-naphthalimide. Then, the binding abilities of this material with different anions and cations were investigated. It was observed that this material was selectively complexed with Cr6+ ion. The fluorescent probe carrying 4-sulfo-1,8-naphthalimide showed a low LOD of 1.45 μM for Cr6+ in the working range of 0.33 × 10−5–3.22 × 10−5 M. In order to transform the prepared material into a more antimicrobial structure, potassium sulfonate groups were converted into silver salts (C-Nap@Ag). Then, naphthyl groups in the chitosan structure were reacted under ZIF-8 conditions and Ag+ ions in the structure were reduced to Ag nanoparticles (C-Nap@Ag@ZIF-8). The antioxidant and antimicrobial properties of the prepared structure were examined. The prepared materials, it was determined that the Ag+ ion carrying material (C-Nap@Ag@ZIF-8) showed more effective antimicrobial activity than the AgNp containing material (C-Nap@AgNp@ZIF-8). This material (C-Nap@Ag@ZIF-8) showed significant antibacterial activity 0.097 mg/mL against S. lutea. The obtained results reveal that this compound is a versatile candidate for both heavy metal ion detection and biological applications.