Thin colorimetric film array for rapid and selective detection of v-type nerve agent mimic in potentially contaminated areas.

The expeditious detection and quantification of V-series nerve agents (VX) on potentially contaminated surfaces are crucial for the prevention of regional conflict incidents, acts of terrorism, or illicit activities. However, the low volatility and high toxicity of VX make these tasks challenging. Herein, we designed two novel colorimetric thin polymeric films to rapidly and sensitively detect demeton-S, a VX mimic, in contaminated areas. The polymeric films were specifically engineered to include a coordination site for Au (III) ions. Initially, these films were coordinated with Au (III), causing a discernible alteration in color due to enhancement in intramolecular charge transfer process. In the presence of demeton-S, the Au (III) ligands in the films are displaced with demeton-S, resulting in the restoration of the original color of the film, as the enhanced intramolecular charge transfer process is inhibited and thereby serving as an indicator of the presence of demeton-S. The polymeric films exhibit remarkable selectivity toward demeton-S compared to G-type nerve agents and other interference. The reusability of the polymeric films for demeton-S detection was achieved owing to the reversibility of the films during the alternative exposure of Au (III) and demeton-S. The polymeric films demonstrated their applicability for demeton-S detection and quantification in several contaminated areas, including different water, soil, and skin, rendering them highly suitable for on-site measurements.

Recyclable macromolecular thermogels for Hg(II) detection and separation via sol-gel transition in complex aqueous environments.

The sensitive detection and quantitative separation of toxic heavy metal ions in aqueous media are of great importance. In this study, a thermogelling poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCL-PEG-PCL) triblock copolymer (P1) was synthesized, and difluoroboron dipyrromethene (BODIPY) fluorophore integrated with thiosemicarbazide units was attached to the chain ends of P1 through consecutive post-polymerization modifications, leading to P4. P4 exhibited rapid and selective detection of Hg(II) in 100% aqueous media via turn-on fluorescence emission with a limit of detection (LOD) of as low as 0.461 µM. This turn-on emission behavior is attributed to the suppression of CË­N isomerization caused by the formation of a coordination complex between P4 and Hg(II) ions. The selective and quantitative removal of Hg(II) among various metal ions was achieved by trapping chelated Hg(II) ions inside the dehydrated P4 gel via thermo-controlled sol-gel-dehydrated gel transitions. Treating the Hg(II) ion-trapped dehydrated gels with sodium sulfide (Na2S) in acetone/water at room temperature led to HgS precipitates, and P4 in solution was dried and recycled. This recyclable thermoresponsive macromolecular probe is promising for not only Hg(II) detection but also its separation and removal from complex aqueous environments.

Effect of dentin on the antimicrobial efficacy of 3% sodium hypochlorite, 2% chlorhexidine, 17% ethylenediaminetetraacetic acid, and 18% etidronic acid on Candida albicans: An in vitro study.

AIM: The aim of this study was to evaluate the effect of dentin on the antimicrobial efficacy of 3% sodium hypochlorite, 2% chlorhexidine, 17% EDTA and 18% etidronic acid against C. albicans. METHODOLOGY: Dentin powder was prepared from mandibular first premolar using electrical grinder and sterilized. 3% NaOCl, 2%CHX, 17% EDTA and 18% etidronic acid were tested against C. albicans in the presence and absence of dentin, in eppendorf tubes. Group 1 (presence of dentin):- 100ul dentin powder + 100ul C. albicans suspension + 100ul irrigating solution. Group 2 (absence of dentin):- 100ul C. albicans suspension+ 100ul irrigating solution. CONTROL GROUP: - 100ul C. albicans suspension.+ 100ul sterile saline Suspension was thoroughly mixed, submitted for serial dilution upto10-5 after 1 min and colony forming units were counted. RESULTS: In group 2 (without dentin powder), 3% NaOCl and 2% CHX showed the lowest bacterial count compared to group 1 (with dentin powder). Dentin had a significant inhibitory effect on 3% NaOCl (P < 0.001) and 2% CHX (P<0.001). 17% EDTA showed lowest bacterial count in group 1 (with dentin powder) compared to group 2 (without dentin powder). 18% Etidronic acid showed similar bacterial counts in the both the groups. No reduction was observed in the control group. CONCLUSION: NaOCl & EDTA showed measurable antimicrobial effect even in the presence of dentin which can be promising in the reduction of C. albicans in root canal therapy.