Combined detection of SARS-CoV-2 neutralizing antibodies and specific IgG in plasma based on SERS magnetic sensor.

In this study, a surface-enhanced Raman spectroscopy (SERS) magnetic sensor is established based on SERS principle and magnetic separation technology, and a highly sensitive, simple and fast method for quantitative detection of neutralizing antibodies (nABs) and specific IgG of SARS-CoV-2 in plasma is established combined with immunoassay. Two kinds of Raman nanospheres (RNPs) with different characteristic Raman shifts are used as signal sources and coupled to ACE2 and anti-IgG (FC) antibodies respectively, and magnetic beads are coupled to RBD. The competitive relationship between ACE2 and nABs, the binding relationship between specific IgG and anti-IgG (FC) antibodies are determined. The results show that the concentrations of nABs and specific IgG in the range of 10-2000 ng ml-1are well correlated with SERS response intensity, and the recoveries are both between 90%-110%, with good precision. Bilirubin and common anticoagulants have no interference on the detection results. This method is accurate, reliable, sensitive and does not require complex pre-treatment, and is expected to be used for simultaneous detection of nABs and specific IgG in plasma of SARS-CoV-2. It has guiding significance for the development and evaluation of vaccines and the formulation of individualized vaccination schedule.

Study on the performance of novel nanomaterials for detection of biomarkers such as PCT based on immunochromatography sensitivity.

In this study, by comparing the UV-vis spectral characteristics of colloidal gold and colloidal gold enhancer, and their differences as immunochromatographic tracers in the qualitative detection of PCT, IL-6, Hp and quantitative determination of PCT performance, the factors that may affect the sensitivity were discussed. The results show that the absorbance at 520 nm of CGE diluted 20-fold and colloidal gold diluted 2-fold were comparable, and the sensitivity of CGE immunoprobe for qualitative detection of PCT, IL-6 and Hp was higher than that of colloidal gold immunoprobe, and the reproducibility and accuracy of both immunoprobes for quantitative detection of PCT were good. Indicating that the high sensitivity of CGE immunoprobe detection is mainly due to the absorption coefficient of CGE at 520 nm is about 10 times that of colloidal gold immunoprobe, CGE has stronger light absorption capacity and stronger quenching effect on rhodamine 6 G on the nitrocellulose membrane surface of the test strip.

Synchronous detection of IgG subtypes based on SERS combined with immunoassay.

In this study, a rapid, simple, highly sensitive and anti-interference method for the joint detection of four IgG subtypes is established by using Raman microspheres with four characteristic Raman spectra. The results show that the concentrations of IgG1 in the range of 0-1500 ng ml-1, IgG2 in the range of 0-1100 ng ml-1, IgG3 in the range of 0-88.7 ng ml-1, IgG4 in the range of 0-77.2 ng ml-1, it shows a good correlation with the response value of The Raman signal. The lowest detection limits are 25.4 ng ml-1, 21.7 ng ml-1, 1.6 ng ml-1, 1.7 ng ml-1, respectively. Reproducibility is good, the coefficient of variation of low, medium and high concentration standard solution are within 10%. The recoveries of four IgG subtypes are in the range of 90%-110%, and the accuracy of the method is good. The coefficients of variation between and within the three batches of reagents are all less than 11%, showing good precision. There is no cross reaction with Procalcitonin (20 ng ml-1), Interleukin-6 (1 ng ml-1) and bovine serum albumin (10 mg ml-1), and the specificity is good. Common interfering substances such as bilirubin, triglyceride and trisodium citrate do not affect the determination results, and heparin sodium only affects the determination results of IgG1. This method has good anti-interference ability. The method has high sensitivity, simple operation and strong anti-interference ability, and has good correlation with the IgG detection methods commonly used in clinic. This simple and quantitative method can be used for the rapid detection of IgG subtypes in the future, which can improve the efficiency of clinical diagnosis.

Procalcitonin in general internal medicine: a bibliometric analysis.

BACKGROUND: Procalcitonin (PCT) plays an important role in the identification of bacterial infection and therapy guidance. The relevant literature is mainly classified under critical care medicine or infectious disease. The research status of PCT in general internal medicine (GIM) is currently unclear. This research aimed to analyze PCT-related literature in the GIM field and provide references for future research. METHODS: A subject search strategy was used for the term PCT, with the search scope limited to Medicine, General & Internal. We conducted a search of relevant literature in the Science Citation Index Expanded (SCIE) database in the Web of Science Core Collection (WOSCC), with no publication date limit (1900 to May 16, 2021, the date of the final search for this study). The search results were analyzed using CiteSpace software to assess the status of PCT research in the GIM field based on annual paper publication numbers, the number of citations, country distribution, institution distribution, author distribution, journal distribution, and keyword usage. RESULTS: A total of 905 document records were retrieved. Articles were mainly from Europe, the United States, and China, and the number of citations totaled 15,917. There were 5 research institutions that published more than 10 related papers and 3 authors who published more than 10 papers. There was little cooperation between authors from different countries and institutions. This field should focus on leading journals in critical care medicine and quality comprehensive journals. Keyword analysis showed that the current research focus is the standardized application of PCT. CONCLUSIONS: There are few targeted studies on the application of PCT in GIM, and the relevant important literature mainly comes from other journals. GIM-specific research should be increased in the future.

Plasma soluble human leukocyte antigen G predicts the long-term prognosis in patients with colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) is the third most common tumor in the world. It is crucial to further screen for indicators that are strictly related to long-term prognosis. Human leukocyte antigen G (HLA-G) is closely involved in tumor development. This study aims to evaluate the long-term predictive value of soluble HLA-G (sHLA-G) in CRC through a double-center retrospective study. METHODS: Patients who underwent radical CRC surgery in two hospitals from April 2010 to March 2015 were included. Baseline data of the patients were collected. The patients' preoperative baseline plasma sHLA-G level was detected. According to whether they survived during five years of follow-up, these patients were divided into two groups. Univariate and multivariate analysis were used to find factors associated with survival. The receiver operation curve (ROC) was performed to analyze the relationship between sHLA-G level and five-year survival, and the cutoff value was obtained. The baseline data and follow-up results of the two groups of patients were compared, and the Kaplan-Meier survival curve was used to analyze the difference in the long-term prognosis of the two groups of patients. RESULTS: A total of 1,037 cases were included and followed up for more than five years. Three hundred two cases (29.1%) died during the five-year follow-up. The baseline data of the survival group and the death group showed that the baseline level of sHLA-G in the survival group was significantly lower than the death group (41.4±16.9 vs. 64.7±23.2, P<0.05). Univariate and multivariate analyses suggest that age, differentiation, family history, TNM stage, and baseline sHLA-G levels are important factors affecting the survival of CRC patients. The area under ROC of sHLA-G with five-year survival is 0.766, and the cutoff value is 50.8 U/mL. The specificity at this point is 78.1%, and the sensitivity is 72.3%. The Kaplan-Meier survival curve showed that the five-year prognosis of patients in the low-level group was better than that in the high-level group. CONCLUSIONS: Lower baseline sHLA-G level predicts better prognosis during a five-year follow-up in colorectal cancer patients.