An innovative immunochromatographic assay employing Pt-Pd bimetallic nanoparticles as labels for the detection of foot-and-mouth disease virus serotype O.

OBJECTIVE: We created a novel, high sensitivity immunochromatographic assay that allows for clear and precise quantitative analysis by employing innovative bimetallic nanoparticles with peroxide-like activity as markers for the preparation of the test strip. METHODS: Initially, we synthesized Pt-Pd bimetallic nanoparticles through the reduction of K2PtCl4 and Na2PdCl4 using ascorbic acid (AA) in an ultrasonic water bath. These bimetallic nanoparticles were then utilized to label purified antigens from the foot-and-mouth disease virus (FMDV) type O (FMDV-146S), resulting in the creation of antigen-captured nanomarkers. Upon completion of the antigen-antibody reaction, we introduced a color-developing agent (3,3',5,5'-tetramethylbenzidine) for cascade amplification, significantly enhancing detection sensitivity while ensuring clear and accurate quantitative analysis. RESULTS: The quantitative detection sensitivity achieved was 1:28/test, with a linear range spanning from 1:26 âˆ¼ 1:29 /test. For FMDV type O positive serum, the detection sensitivity reached 96.7 %. Furthermore, this method exhibited a 95 % detection sensitivity for FMDV negative serum, FMDV type A and type AsiaⅠ positive sera, as well as sera positive for other common viral diseases in animals. In comparison to the OIE-recommended LPB-ELISA, this approach displayed higher correlation (correlation coefficient = 0.909). Innovation was at the core of establishing this immunochromatographic assay based on Pt-Pd bimetallic nanoparticles for the detection of FMDV antibodies. CONCLUSION: The findings revealed a striking 24-fold improvement in sensitivity when compared to colloidal gold, accompanied by a strong correlation coefficient (R2 > 0.9). This suggests a robust and consistent linear association in the results. This method represents a significant advancement in the field of rapid immunochromatographic assays, offering a promising alternative application for bimetallic nanoparticles.

Antioxidant activities of cold-nature Tibetan herbs are signifcantly greater than hot-nature ones and are associated with their levels of total phenolic components.

Tibetan medicinal plants have been used for more than 2 000 years. In order to find their differences in antioxidant activity, total phenolics and total flavonoids between "hot-nature" and "cold-nature" herbs, we investigated the antioxidant activities of 40 Tibetan herbs from Qinghai plateau, with 20 herbs in cold-nature and 20 herbs in hot-nature. Antioxidant capacities were evaluated by the following methods: scavenging ABTS•(+) (2, 2'azinobis-(3-ethylbenz-thiazoline-6-sulfonic acid), scavenging O2•(-), and Ferric-reducing antioxidant power (FRAP). The effects on inhibition of mitochondrion lipid peroxidation were determined by measuring the formation of TBARS (Thiobarbituric acid reactive substrates). Total phenolics and flavonoids were estimated by Folin-Ciocalteu and NaNO2-Al(NO3)3-NaOH colorimetric methods. Interestingly, the cold-nature herbs displayed higher antioxidant activities than the hot-nature ones, corresponding to nearly three-fold higher total phenolic contents in the cold-nature herbs. Moreover, the antioxidant activities correlated linearly with the levels of total phenolics for both cold-nature and hot-nature herbs, but only with the levels of total flavonoids for the hot-nature herbs. The results suggested that the phenolic compounds, but not the flavonoids, play the major role in antioxidant capacities of the cold-nature herbs. These findings could shed new lights on the study the theory of Tibetan medicine.

Oridonin induces the apoptosis of metastatic hepatocellular carcinoma cells via a mitochondrial pathway.

The selective induction of apoptosis is a promising strategy for cancer therapy. The antitumor effects of oridonin have been reported in several types of malignant tumors. However, the effects of oridonin on MHCC97-H cells, a highly metastatic human hepatocellular carcinoma cell line, have not been reported. The present study aimed to determine the effect of oridonin on the apoptosis of MHCC97-H cells and to identify the underlying molecular mechanisms that are involved. Compared with the untreated control cells, oridonin significantly decreased (P<0.05) cell proliferation in a concentration- and time-dependent manner. Oridonin at concentrations of 12.5, 25, 50 and 100 µM resulted in increased apoptotic Annexin V-positive and propidium iodide-negative cells by 9.5, 15.6, 22.2 and 31.7%, respectively, compared with the control groups (P<0.05). The mitochondrial membrane potential was significantly decreased by 6.0, 12.9, 18.9 and 27.1% in the MHCC97-H cells that were treated with oridonin at concentrations of 12.5, 25, 50 and 100 µM, respectively, for 24 h compared with the control groups (P<0.05). Oridonin increased the activity of caspase-3 and the expression of cleaved caspase-9 and cytochrome c in the cytoplasm and decreased the Bcl-2:Bax ratio in a concentration-dependent manner. The data indicate that oridonin inhibited the proliferation of the MHCC97-H cells by inducing apoptosis via a mitochondrial pathway. This mitochondrial pathway of apoptosis involved a reduction in the mitochondrial membrane potential and the subsequent release of cytochrome c and activation of caspase-3 and -9.