Research on the dentification of Panax ginseng and Panax quinquefolium using catalysed hairpin assembly technology.

INTRODUCTION: Panax ginseng and Panax quinquefolium are traditional Chinese herb medicines and similar in morphology and some chemical components but differ in drug properties, so they cannot be mixed. However, the processed products of them are often sold in the form of slices, powder, and capsules, which are difficult to identify by traditional morphological methods. Furthermore, an accurate evaluation of P. ginseng, P. quinquefolium and the processed products have not been conducted. OBJECTIVE: This study aimed to establish a catalysed hairpin assembly (CHA) identification method for authenticating products made from P. ginseng and P. quinquefolium based on single nucleotide polymorphism (SNP) differences. METHOD: By analysing the differences of SNP in internal transcribed spacer 2 (ITS2) in P. ginseng and P. quinquefolium to design CHA-specific hairpins. Establish a sensitive and efficient CHA method that can identify P. ginseng and P. quinquefolium, use the sequencing technology to verify the accuracy of this method in identifying Panax products, and compare this method with high-resolution melting (HRM). RESULTS: The reaction conditions of CHA were as follows: the ratio of forward and reverse primers, 20:1; hairpin concentration, 5 ng/µL. Compared with capillary electrophoresis, this method had good specificity and the limit of detection was 0.5 ng/µL. The result of Panax product identification with CHA method were coincidence with that of the sequencing method; the positive rate of CHA reaction was 100%. CONCLUSION: This research presents an effective identification method for authenticating P. ginseng and P. quinquefolium products, which is helpful to improve the quality of Panax products.

Development and application of a visualization method for identification of Panax species with LAMP and a DNAzyme.

Panax ginseng and Panax quinquefolium are two valuable Chinese herbal medicines that should not be mixed because they differ in drug properties and efficacy. The traditional identification method is easily affected by subjective factors and cannot effectively distinguish between ginseng products. This study aimed to develop a new chemical analysis method to visually identify P. ginseng and P. quinquefolium. In this method, a large number of sequences containing G-quadruplex were generated by loop-mediated isothermal amplification, and the combination of G-quadruplex and hemin was used to form deoxyribozyme, which catalyzed the color change of H2O2. Artificial simulation of adulteration experiments revealed that this method could detect more than 20% adulterated P. quinquefolium. Compared with the traditional identification methods, this technology was simpler and more efficient, providing a reference for developing rapid visual identification methods and reagents for P. ginseng and P. quinquefolium.

Dual-recognition colorimetric sensing of thrombin based on surface-imprinted aptamer-Fe3O4.

Thrombin plays an essential role in blood coagulation and some physiological and pathological processes. The convenient, rapid, sensitive, and specific detection of thrombin is of great significance in clinical research and diagnosis. Herein, surface molecularly imprinted polymer (MIP) was modified on aptamer-functionalized Fe3O4 nanoparticles (MIP-aptamer-Fe3O4 NP) for thrombin colorimetric assay by taking advantage of the peroxidase-like activity of Fe3O4 NP. With the adsorption of thrombin into imprinted cavities, the exposed surface area of Fe3O4 NP decreased, causing a decrease in its peroxidase-like activity toward 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2. On the other hand, the reductive amino acids on the thrombin surface also impeded the oxidation of TMB. Both phenomena caused the light blue color of the sensing solution. Thus, a specifically sensitive colorimetric approach for the visual detection of thrombin was proposed with a linear range and limit of detection of 108.1 pmol L-1-2.7 × 10-5 mol L-1 and 27.8 pmol L-1, respectively. Moreover, due to the double recognition elements of MIP and aptamer, the prepared MIP-aptamer-Fe3O4 NP showed higher selectivity to thrombin than that based on only one recognition element. It is worth noting that no special property (e.g. electrochemical or fluorescence activity) of the template was required in this work. Thus, more template molecules can be easily, selectively, and sensitively detected based on the proposed MIP-aptamer-mimic enzyme colorimetric sensing strategy.