Synthesis of a dual-functional fluorescent zinc-based metal organic framework for antibacterial and anti-counterfeit ink applications

Developing low-cost and environmentally friendly methods for synthesizing multifunctional materials with antibacterial and anti-counterfeiting properties remains a significant challenge. In this study, a fluorescent zinc-based metal-organic framework (HNA-Zn MOF) was synthesized via a one-pot solvothermal method using 3-hydroxy-2-naphthoic acid (HNA) as the organic ligand and zinc nitrate hexahydrate as the metal source. The resulting HNA-Zn MOF exhibited stable fluorescence and antibacterial properties. This dual-functional HNA-Zn MOF used in formulating fluorescent ink by blending with an air-dried alkyd resin in ethanol. The ink-coated papers were dried for 1 h at 60 °C. Notably, the HNA-Zn MOF demonstrated outstanding stability after 6 months of storage at room temperature, maintaining 99.9 % of its initial fluorescence emission intensity. In addition to ink formulation, the HNA-Zn MOF was successfully incorporated into fluorescent QR codes, hydrogels, and bio-composite films, all of which retained their luminescent characteristics. Furthermore, HNA-Zn MOF has exhibited a zone of inhibition of 18.3 ± 0.12 mm against E. coli and 20.0 ± 0.08 mm against S. aureus The use of HNA as a dual-functional ligand in a Zn-MOF platform presents a novel route for multifunctional inks with real-world applicability. This method offers a simple way to create functional fluorescent inks that may also provide antimicrobial properties, making them promising for use in anti-counterfeiting technologies.