Eu3+-Doped Anionic Zinc-Based Organic Framework Ratio Fluorescence Sensing Platform: Supersensitive Visual Identification of Prescription Drugs.

Advanced techniques for both environmental and biological prescription drug monitoring are of ongoing interest. In this work, a fluorescent sensor based on an Eu3+-doped anionic zinc-based metal-organic framework (Eu3+@Zn-MOF) was constructed for rapid visual analysis of the prescription drug molecule demecycline (DEM), achieving both high sensitivity and selectivity. The ligand 2-amino-[1,1'-biphenyl]-4,4'-dicarboxylic acid (bpdc-NH2) not only provides stable cyan fluorescence (467 nm) for the framework through intramolecular charge transfer of bpdc-NH2 infinitesimal disturbanced by Zn2+ but also chelates Eu3+, resulting in red (617 nm) fluorescence. Through the synergy of photoinduced electron transfer and the antenna effect, a bidirectional response to DEM is achieved, enabling concentration quantification. The Eu3+@Zn-MOF platform exhibits a wide linear range (0.25-2.5 µM) to DEM and a detection limit (LOD) of 10.9 nM. Further, we integrated the DEM sensing platform into a paper-based system and utilized a smartphone for the visual detection of DEM in water samples and milk products, demonstrating the potential for large-scale, low-cost utilization of the technology.

Gold Nanoparticles-Amplified Indirect Competitive Enzyme-Linked Immunosorbent Assay of BDE-121 Using a Monoclonal Antibody.

In this study, we developed a monoclonal antibody against 2,3',4,5',6-pentabromodiphenylether (BDE-121) using a synthesized hapten, and established an indirect competitive enzyme-linked immunosorbent assay (IC-ELISA), using gold nanoparticles, to amplify the signal. The monoclonal antibody showed high specificity, with a half inhibitory concentration (IC50) value of 2.78 ng/mL, towards BDE-121. The developed IC-ELISA exhibited high sensitivity and stability as well as good recovery. The intra-assay deviation is below 6.8% and the inter-assay deviations range from 6.5% to 8.7%. The assay of the actual samples was found to be consistent with those of gas chromatography/mass spectrometry (GC/MS).

Rational design of specific ligands for human serum albumin separation and applications.

Human serum albumin is widely used in clinical practice, and the development of new ligands with high affinity is beneficial to improve its separation efficiency. The Site II of human serum albumin is an active binding site of various molecules such as l-tryptophan, which was studied with molecular simulation to obtain insights for the design of new ligands. The results showed that the carboxyl and indolyl groups of l-tryptophan were critical for the binding on Site II. Seven ligands containing carboxyl groups and indolyl groups were designed, and molecular simulation showed that indole-3-pentanoic acid was the best ligand. A new ligand combined indole-3-acetic acid and cysteine was designed for easier resin preparation, and molecular simulation also indicated that the new ligand bound strongly to Site II. Resins with the new ligand designed was prepared and static adsorption experiments indicated that the new resin had high adsorption capacity of human serum albumin and strong salt tolerance. Finally, recombinant human serum albumin was separated from yeast broth with high purity of 90.4% and recovery of 94.2%, which indicated that the new resin had good adsorption selectivity and strong potential for applications.

Apatinib, a selective VEGFR2 inhibitor, improves the delivery of chemotherapeutic agents to tumors by normalizing tumor vessels in LoVo colon cancer xenograft mice.

Tumor vascular normalization has been proposed as a therapeutic strategy for malignant neoplasms, which can also interpret the synergistic effect of anti-angiogenesis agents combined with chemotherapy. Apatinib (Apa), a highly selective VEGFR2 inhibitor, attracts much attentions due to its encouraging anticancer activity, especially in the clinical trials of combined treatment. In this study, we investigated whether Apa could promote vascular normalization in tumor in a certain time window. Mice bearing LoVo colon cancer xenograft were orally administrated Apa (150 mg kg-1 per day) for 5, 7, 10, or 12 days. Apa significantly inhibited tumor growth and decreased the microvessel density. Using multi-photon microscopy and electron microscopy, we found that Apa improved tumor vessel morphology by pruning distorted vessel branches and decreased the gap between endothelial cells after a 7-day treatment. Furthermore, Apa decreased vessel leakage and increased pericyte coverage on vascular endothelial cells, suggesting that tumor vessels were more mature and integrated. The intratumoral distribution of adriamycin (ADR) in Apa group was improved from day 7 to 10 without change in plasma drug concentration. Tumor blood perfusion was also increased in this window, and the expression of hypoxia induced factor 1α was downregulated, suggesting the effect of Apa on alleviating tumor hypoxic micro-environment. In conclusion, Apa may improve the effective perfusion of tumor vessels and increase the intratumoral distribution of ADR in a certain time window via normalizing tumor vessels. This normalization window (7 to 10 days of treatment) may contribute to develop a regimen of combined medication in clinic use of Apa.

Dual-chemiresistor GC detector employing monolayer-protected metal nanocluster interfaces.

The synthesis and testing of two gold-thiolate monolayer-protected (nano)clusters as interfacial layers on a dual-chemiresistor vapor sensor array are described. Responses (changes in dc resistance) to each of 11 organic solvent vapors are rapid, reversible, and linear with concentration at low vapor concentrations, becoming sublinear at higher concentrations. Limits of detection (LODs) range from 0.1 to 24 parts per million and vary inversely with solvent vapor pressure. When configured as a GC detector and used to analyze 0.5-L preconcentrated samples of the 11-vapor mixture, the array provides LODs of < or = 700 parts per trillion for most vapors, comparing favorably with those from an integrated array of polymer-coated surface acoustic wave sensors configured and tested similarly. This first report on the use of such an array as a GC detector shows that the combination of response patterns and GC retention times improves capabilities for vapor recognition compared to the sensor array alone or to single-detector GC systems. Spray-coated nanocluster thin films can be deposited reproducibly and exhibit response stability in air that ranges from fair to excellent for up to several months. Scaling the active device area down by a factor of 16 has no significant effect on sensitivity. Implications of these results for portable vapor sensing systems are discussed.