A Highly Sensitive and Rapid Colloidal Gold Immunoassay for Puerarin Detection.

Radix Puerariae is a traditional Chinese medicinal material with a rich history of use in East and Southeast Asia. Puerarin, a unique component of the Pueraria genus, serves as a quality control marker for herbal medicines like Pueraria lobata and Pueraria thomsonii in China, displaying diverse pharmacological properties. This study developed puerarin colloidal gold immunoassay dipsticks utilizing an anti-puerarin monoclonal antibody, resulting in a fast and sensitive detection method with a limit of 500-1000 ng·mL-1. Evaluation using tap water-extracted P. lobata and P. thomsonii samples showed consistent results compared to LC-MS analysis. Cross-reactivity assessments of puerarin analogs revealed minimal interference, affirming the dipstick's reliability for distinguishing between the two species.

Generating Monoclonal Antibodies against Buprofezin and Developing Immunoassays for Its Residue Detection in Tea Samples.

The synthesis of a hapten and antigen for the preparation of a monoclonal antibody (mAb) for buprofezin is described. The recognition mechanism of hapten and buprofezin by monoclonal antibodies (mAb-19F2) is described. The effectiveness of the mAb-19F2 immunoassay technique was assessed, and the effective detection of buprofezin in tea samples was achieved through the establishment of indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and colloidal gold immunochromatography assay (GICA). The mAb-19F2 subtype was IgG1, with an IC50 of 1.8 ng/mL and a linear range (IC20-IC80) of 0.6-5.4 µg/L, and had a cross-reaction rate of less than 0.18% with 29 other pesticides (neonicotinoids and insect growth regulators). The study identified π-π stacking interactions between hapten and TYR-61 at the mAb-19F2 site and alkyl/phosphate interactions with TRP-105 and ARG-103. The ic-ELISA had an IC50 of 12.9 ng/mL in green tea and 5.65 ng/mL in black tea, with a recovery rate of 92.4%-101.0% and RSD of 2.1%-4.8%. The GICA had a limit of detection (LOD) was 500 ng/mL, with the complete disappearance of the test lines visible to the naked eye. The limit of quantitation (LOQ, IC20) was determined to be 16.8 ng/mL. Additionally, the developed GICA showed no cross-reactivity with neonicotinoid pesticides. The recovery rate of tea spiked recovered samples was 83.6%-92.2%, with an RSD of 5.3%-12.6%, and the results were consistent with the LC/MS method. This study is important for the real-time detection of buprofezin residues to ensure food safety and human health.

Antioxidant and Anti-Melanogenesis Effects of Colloidal Gold Camellia sinensis L. Extracts.

Green tea extract derived from the leaves of Camellia sinensis L. (CS), is a representative beverage with antioxidant, anti-cancer, and anti-viral properties. CS extract is also used in cosmetics. Colloidal gold is generally a sol or colloidal suspension of gold nanoparticles in water. Colloidal gold green tea (CGCS), cultivated as a fertilizer using this colloidal gold solution, contains gold minerals and possesses anti-inflammatory, analgesic, and anti-tumor properties. However, the skin bioactivity of CGCS has not yet been investigated. In this study, we investigated the effect of the CGCS extract on skin whitening. CGCS extract contained high levels of phenols and flavonoids and displayed 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity in a concentration-dependent manner. CGCS extract inhibited melanin synthesis and tyrosinase activity in B16F10 cells more effectively than the CS extract. Moreover, the CGCS extract decreased the expression levels of the melanogenesis-related proteins, tyrosinase, tyrosinase-related proteins (TRPs), and microphthalmia-associated transcription factor (MITF). In conclusion, our study showed that the CGCS extract inhibits the expression of tyrosinase, TRP-1, and TRP-2 via the downregulation of MITF, thereby inhibiting melanin synthesis. Therefore, CGCS can potentially be used as a skin-whitening ingredient in the cosmetic industry.

The colloidal gold nanoparticle-based lateral flow immunoassay for fast and simple detection of plant-derived doping agent, higenamine.

Higenamine (HM), an alkaloid found in various plant species, is obtained when norcoclaurine synthase selectively condenses dopamine and 4-hydroxyphenylacetaldehyde to give (S)-higenamine ((S)-HM). The World Anti-doping Agency has listed HM as a prohibited agent in athletics. As a result, many commercial, academic, and regulatory bodies across the globe are invested in finding a rapid method for (S)-HM detection. In the current study, a lateral flow immunoassay (LFA) was developed in which the relevant biosensor was generated as a conjugate of the monoclonal antibody against (S)-HM (namely, MAb E8) and colloidal gold nanoparticles. The HM-γ-globulin conjugates and rabbit anti-mouse IgG antibodies were placed in the test and control zones, respectively. The free (S)-HM molecules in the samples and the immobilized HM-γ-globulin conjugates competitively reacted with the developed biosensor in the LFA. An inverse relationship existed between the biosensors' visible response, which was noted by the variation in the intensity of a pinkish spot in the test zone, and the content of the free (S)-HM. The limit of detection of the developed LFA was 156 ng/mL. Various validation methods confirmed that the LFA exhibited sufficient sensitivity, selectivity, repeatability, and reliability, making it ideal for (S)-HM detection in plant samples and plant-containing products. The developed system required only a small sample volume (20 µL) and a concise sample preparation time compared with conventional LFAs. Thus, the LFA reported in this study could serve as a rapid response kit for the detection of (S)-HM in plant samples.

Quantitative Detection of Aflatoxin B1 in Traditional Chinese Medicine by Colloidal Gold Immunochromatography / 中国药学杂志

OBJECTIVE：To explore the feasibility of using colloidal gold immunochromatography for quantitative detection of aflatoxin B1 in traditional Chinese medicine. METHODS：Negative samples were used to investigate matrix interference by different levels of spikes.The rapid inspection performance was evaluated by examining the precision, sensitivity, linearity, repeatability and recovery rate. The sample was determined by rapid test method and verified by HPLC. RESULTS：High-concentration and low-concentration aflatoxin B1 reference materials were added to the negative sample matrix. After the measurement, it was found that there were matrix interferences in the samples such as tangerine peel and cassia seed, and the interference was greater when the concentration was increased. So high dilution factor was used to reduce the interference. The precision RSD of the rapid test method was 4.6% (n=10), the reproducibility RSD was 4.1% (n=6), and the recoveries of different samples were between 72.8% and 112.8%. The overall performance of the method was good. A total of 43 batches of 19 kinds of medicinal materials such as silkworm, cockroach and leeches were detected by two methods. The coincidence rate between the fast test and the HPLC test was 83.7%. Therefore, the results obtained by the two detection methods were considered to be approximate. CONCLUSION：Colloidal gold immunochromatographic rapid test method can be used for the quantitative detection of aflatoxin B1 in some traditional Chinese medicines, and provides technical support for the establishment and improvement of relevant rapid detection standard methods.

[Application of immunoassay in fast quality evaluation of traditional Chinese medicine].

The quality evaluation of traditional Chinese medicine can be divided into two aspects, effectiveness and safety. The existing methods for evaluating the quality of traditional Chinese medicine(TCM) are mostly based on the testing instruments, which can not meet the practical needs of simple, rapid and on-site in production and life. Immunoassay, characterized by simple, rapid, sensitive, specific, low-cost and high-throughput, is widely used in the fields of clinical diagnosis, environmental pollution monitoring, food safety testing, and other fields. In recent years, immunoassay technology has been gradually applied in the field of quality control of TCM, involving quantitative detection of effective components of TCM, detection of harmful substances in TCM, and detection of exogenous pollutants in TCM. This paper summarizes the principle of the wide application of ELISA and colloidal gold immunostrip technology and its application in quality evaluation of TCM, this technique has a good application prospect in the field of rapid detection of the quality of TCM. In this paper, the principles of the widely used ELISA and colloidal gold immune test strip technology as well as their application in quality evaluation of TCM were reviewed, and the results showed that this technique had a good application prospect in the field of rapid detection of the quality of TCM.

Application of immunoassay in fast quality evaluation of traditional Chinese medicine / 中国中药杂志

The quality evaluation of traditional Chinese medicine can be divided into two aspects, effectiveness and safety. The existing methods for evaluating the quality of traditional Chinese medicine(TCM) are mostly based on the testing instruments, which can not meet the practical needs of simple, rapid and on-site in production and life. Immunoassay, characterized by simple, rapid, sensitive, specific, low-cost and high-throughput, is widely used in the fields of clinical diagnosis, environmental pollution monitoring, food safety testing, and other fields. In recent years, immunoassay technology has been gradually applied in the field of quality control of TCM, involving quantitative detection of effective components of TCM, detection of harmful substances in TCM, and detection of exogenous pollutants in TCM. This paper summarizes the principle of the wide application of ELISA and colloidal gold immunostrip technology and its application in quality evaluation of TCM, this technique has a good application prospect in the field of rapid detection of the quality of TCM. In this paper, the principles of the widely used ELISA and colloidal gold immune test strip technology as well as their application in quality evaluation of TCM were reviewed, and the results showed that this technique had a good application prospect in the field of rapid detection of the quality of TCM.

Immunochromatographic strip assay for detection of bioactive Ganoderma triterpenoid, ganoderic acid A in Ganoderma lingzhi.

Ganoderic acid A (GAA) is one of the major Ganoderma triterpenes produced by medicinal mushroom belonging to the genus Ganoderma (Ganodermataceae). Due to its interesting pharmacological activities, Ganoderma species have been traditionally used in China for the treatment of various diseases. Herein, we developed a colloidal gold-based immunochromatographic strip assay (ICA) for the rapid detection of GAA using highly specific monoclonal antibody against GAA (MAb 12A) conjugated with gold nanoparticles. Using the developed ICA, the detection of GAA can be completed within 15min after dipping the test strip into an analyte solution with the limit of detection (LOD) for GAA of ~500ng/mL. In addition, this system makes it possible to perform a semi-quantitative analysis of GAA in Ganoderma lingzhi, where high reliability was evaluated by enzyme-linked immunosorbent assay (ELISA). The newly developed ICA can potentially be applied to the standardization of Ganoderma using GAA as an index because GAA is major triterpenoid present much in the mushroom.

Establishment of small molecular monoclonal antibody technology platform in Chinese materia medica / 中草药

Antibody is a tool of vital importance in modern bioscience research, small molecular antibody technology has a broad application prospect in the field of receptor binding analysis, enzyme assays, and quantitative and/or qualitative analytical techniques of Chinese materia medica (CMM) research. In this paper, combining with the research work carried out by our innovation team, we introduced the establishment background of the small molecular monoclonal antibody technology platform in CMM and technical difficulties in antibody preparation. In view of the technology products based on small molecular monoclonal antibody of CMM, such as ELISA test kit, immune affinity chromatography column, colloidal gold test paper, fluorescently labeled antibodies, and antibody microarrays, we explored and practised the various applications based on the small molecular monoclonal antibody technology looking forward to its scientific significances and application values in the field of CMM research.