A bi-modal, cellulose-based sensor for fluorometric detection of Fe(III) and antimicrobial studies of its silver-loaded form

Dual fluorescence response of calix[4]arene-1,8-naphthalimide derivatives towards Hg(II) /Cr(VI) and their antimicrobial studies of transparent biofilms with hyaluronic acid

In this study, 4-sulfo-1,8-naphthalimide calixarene of derivatives were prepared (3 and 4) then transparent biofilms of the Ag salts of these compounds were formed in the presence of hyaluronic acid (HA), and antimicrobial properties were investigated. In chemosensor studies, the sensing ability behavior of 3 and 4 towards some cations and anions was investigated by fluorescence spectroscopy. It was observed that the prepared chemosensors show selectivity towards Hg(II) and Cr(VI). Ligand-ion interaction occurs according to the photo-induced electron transfer (PET) mechanism. The stoichiometric ratio was calculated by using Stern-Volmer plot method and binding constant Ksv values were found as 5.2 × 107 M-1 and 5.5 × 107 M-1 for 3-Hg(II) and 4-Hg(II) complexes, respectively and 4.0 × 107 M-1 and 4.3 × 107 M-1 for 3-Cr(VI) and 4-Cr(VI) complexes. The detection limits of the complexes of 3-Hg(II) and 4-Hg(II) are 6.35 × 10-12and 6.81 × 10-12, while those of 3-Cr(VI) and 4-Cr(VI) are 1.41 × 10- 11and 8.37 × 10-12, respectively. As a result of the antimicrobial test performed with these compounds, it was observed that the most effective material was HA-3Ag, which showed a significant antibacterial effect against Sarcina lutea (S. lutea) at a minimum inhibitory concentration (MIC) value of 0.097 mg/mL.

Design of a novel fluorescent metal-organic framework (UiO-66-NG) for the detection of boric acid in aqueous medium and bioimaging in a living plant system

UiO-66-NH2 material is a variant of Zr-based MOF most widely used for various applications, exhibiting unprecedented excellent hydrothermal and physicochemical stability. In this study, after UiO-66-NH2 reacted with chlorosulfonyl isocyanate, the fluorescent UiO-66-NG probe was prepared by interacting with the N-methylglucamine molecule. The structure of the prepared probe was confirmed by characterizing them with techniques such as FTIR, SEM, and XRD. The sensing properties of this prepared probe against different anions and cations were investigated and it was understood that it showed sensitive selectivity only for H3BO3. The H3BO3 detection limit (LOD) of the UiO-66-NG probe was determined as 1.81 μM. Boric acid was determined in real samples by using tap water, lake water, and river water. Fluorescence imaging was performed using the plant Lepidium sativum for the detection of boric acid in aqueous medium and for bio-imaging in a living plant system. These results show that the prepared UiO-66-NG can be used successfully in the determination of H3BO3 in living plants.

A cellulose-based material as a fluorescent sensor for Cr(VI) detection and investigation of antimicrobial properties of its encapsulated form in two different MOFs

It is crucial to detect toxic chromium ions quickly, reliably, sensitively and at low concentrations. In recent years, fluorescence-based methods have been developed for the rapid detection and determination of toxic ions such as chromium. In present work, we focused on the development of a cellulose-based fluorescent probe (Cel-Nap) for the determination of Cr(VI). The fluorescent probe bearing the 1,8-naphthalimide group displayed a low LOD of 1.07 μM for Cr(VI) in the working range of 0.33 × 10^-5-3.22 × 10^-5 M. The fluorescence and antibacterial properties of UiO-66-Cel-Nap and ZIF-8-Cel-Nap materials prepared by encapsulating Cel-Nap with 2 different MOF types (UiO-66 and ZIF-8) were investigated. While it was found that ZIF-8-based materials had better antimicrobial properties compared to those of UiO-66, it was determined that materials containing Ag⁺ were more effective against microbial than those containing AgNPs. It was found that the most effective material was ZIF-8-Cel-Nap-Ag⁺ and it had a significant antibacterial effect against E. coli at a MIC value of 0.0024 mg/mL.