A stable cationic Cd(II) coordination network as bifunctional chemosensor with high sensitively and selectively detection of antibiotics and Cr(VI) anions in water

Rapidly and simply detecting Cr (VI) in aqueous media via a diketopyrrolopyrrole-based chemosensor with both high selectivity and low LOD

BACKGROUND

The high toxicity of hexavalent chromium [Cr (VI)] could not only cause harmful effects on humans, including carcinogenicity, respiratory issues, genetic damage, and skin irritation, but also contaminate drinking water sources, aquatic ecosystems, and soil, impairing the reproductive capacity, growth, and survival of organisms. Due to these harmful effects, detecting toxic Cr (VI) is of great significance. However, the rapid, simple, and efficient detection at a low Cr (VI) concentration is extremely challenging, especially in an acidic condition (existing as HCrO4-) due to its low adsorption free energy.

RESULTS

A diketopyrrolopyrrole-based small molecule (DPPT-PhSMe) is designed and characterized to act as a chemosensor, which allows a high selectivity to Cr (VI) at an acidic condition with a low limit of detection to 10-8 M that is two orders of magnitude lower than the cut of limit (1 μM) recommended by World Health Organization (WHO). Mechanism study indicates that the rich sulfur atoms enhance the affinity to HCrO4-. Combining with favorable features of diketopyrrolopyrrole, DPPT-PhSMe not only allows dual-mode detection (colorimetric and spectroscopic) to Cr (VI), but also enables disposable paper-based sensor for naked-eye detection to Cr (VI) from fully aqueous media. The investigation of DPPT-PhSMe chemosensor for the quantification of Cr (VI) in real life samples demonstrates a high reliability and accuracy with an average percentage recovery of 102.1 % ± 4 (n = 3).

SIGNIFICANCE

DPPT-PhSMe represents the first diketopyrrolopyrrole-derived chemosensor for efficient detection to toxic Cr (VI), not only providing a targeted solution to the bottleneck of Cr (VI) detection in acidic conditions (existing as HCrO4-) caused by its low adsorption free energy, but also opening a new scenario for simple, selective, and efficient Cr (VI) detection with conjugated dye molecules.

Computational choreography: dissecting the dance of hydrogen bonding and π-π stacking in the fluorescence discrimination mechanism of ciprofloxacin with supramolecular assembly

The detailed binding insight between the fluorophore and analyte plays a pivotal role in the design of an efficient chemosensor for water pollution. In this study, we designed a picolinic acid-functionalized calix[4]pyrrole ligand (PCACP). When testing out the fluorescence study with selected antibiotics, we observed remarkable enhancement of fluorescence spectra in the presence of ciprofloxacin, singling out the PCACP_Ciprofloxacin complex. The detailed binding mechanism is explored via computational methods including molecular docking and dynamics, DFT (density functional theory) and NBO (Natural Bonding Orbital) analysis. The result of this study provides the comprehensive insight into the involvement of functionalized group of PCACP and ciprofloxacin antibiotic. The results of the computational findings are further explored through NMR complexation study, which corroborate the computational findings. With the limit of detection calculated at 18 µM, we carried out the water sample analysis, which shows promising results. The outcome of this research provides a new, effortless fluorescence approach to monitor the presence of ciprofloxacin in water.In the presence of the ciprofloxacin antibiotic, the fluorescence spectra of PCACP experience remarkable enhancements. This complexation phenomenon is studied through different computational and experimental methods.Communicated by Ramaswamy H. Sarma.

pH-responsive Ag-Phy@ZIF-8 nanoparticles modified by hyaluronate for efficient synergistic bacteria disinfection

Zeolitic imidazolate framework-8 (ZIF-8) is a type of Metal-organic frameworks (MOFs), which shows promising application in the field of bacterial infection, owing to its excellent biocompatibility. Here, we report the encapsulation of silver nanoparticles (Ag NPs) in ZIF-8, accompanied with embedding of physcion (Phy) to obtain Ag-Phy@ZIF-8 with efficient and intelligent synergistic antimicrobial capabilities. Due to the micro-acidic environment around the bacteria, the release of silver and Phy shows a controlled released. Further, the Ag-Phy@ZIF-8 is modified by hyaluronate (HA), denoted as Ag-Phy@ZIF-8@HA, which has a strong inhibitory effect on the growth of both E. coli (99.1%) and S. aureus (99.5%), with no impacting on cell growth, showing good biocompatibility. Thus, these pH-responsive biocomposites have the potential application on smart wound excipients for bacterial infections.

Two coordination polymers as multi-responsive luminescent sensors for the detection of UO22+, Cr(vi), and the NFT antibiotic

Two CPs have been synthesized using solvothermal method and can act as multi-responsive luminescent probe to detect UO22+ cation, Cr2O72−/CrO42− anions, and nitrofuran antibiotic in aqueous media with high sensitivity and selectivity.