Rapid and Sensitive Chemiluminescent Enzyme Immunoassay for the Determination of Neomycin Residues in Milk

Immunoassays greatly contribute to veterinary drug residue analysis. However, there are few reports on detecting neomycin residues by immunoassay. Here, a rapid and sensitive chemiluminescent enzyme immunoassay （CLIEA） was successfully developed for neomycin residue analysis. CLIEA demonstrated good cross-reactivity for neomycin, and the IC50 value was 2.4 ng/mL in buffer.

Determination of theophylline concentration in serum by chemiluminescent immunoassay

Objective: This study aimed to establish chemiluminescent immunoassay (CLIA) for quantitative determination of theophylline levels in human serum. Methods: To measure the concentration of theophylline (n=122) and evaluate the assay.Results: The linear range of the CLIA method was 0.51～40 mg/L (Y=1.02X+0.44, r=0.995). The intra and inter CV (coefficient variance) of CLIA were 3.20% and 3.57%, respectively. The average recovery rate was 102.3%. This method was free from interference by brilirubin (＜200 μmol/L), hemoglobin (＜10 g/L), and triglycerides (＜15 mmol/L). Conclusion: This method is simple, convenient and precise for clinical pharmacokinetics study oftheophylline.

Determination of Progesterone Receptor by Chemiluminescent Enzyme Immunoassay

A new method of chemiluminescent enzyme immunoassay (CLEIA) was developed and the standard curve and regression equation for determination of progesterone receptor (PR) made. The luminosity of tissue samples was tested and PR level was calculated by the regression equation. Correlation analysis revealed that there was a linear relationship between different concentrations of the standard PR samples and the corresponding values of luminosity: Y=3748+463.77X, γ=0 9958. The values of the luminosity in 38 cases of tumor tissues were determined with the highest being 267.32 fmol/mg, the lowest 3.69 fmol/mg and the mean 78.53 fmol/mg. The new method of CLEIA was a stable, creditable,specific and sensitive assay for determination of PR.

Comparison of chemiluminescence enzyme immunoassay based on magnetic microparticles with traditional colorimetric ELISA for the detection of serum α-fetoprotein

A chemiluminescence enzyme immunoassay based on magnetic microparticles (MmPs-CLEIA) was developed to evaluate serum a-fetoprotein (AFP) in parallel with traditional colorimetric enzyme-linked immunosorbent assay (ELISA).A systematic comparison between the MmPs-CLEIA and colorimetric ELISA concluded that the MPs-CLEIA exhibited fewer dosages of immunoreagents,less total assay time,and better linearity,recovery,precision,sensitivity and validity.AFP was detected in forty human serum samples by the proposed MPs-CLEIA and ELISA,and the results were compared with commercial electrochemiluminescence immunoassay (ECLIA) kit.The correlation coefficient between MPs-CLEIA and ELISA was obtained with R 2 0.6703;however,the correlation between MPs-CLEIA and ECLIA (R 2 0.9582) was obviously better than that between colorimetric ELISA and ECLIA (R 2 0.6866).

Summary of the Detection Kits for SARS-CoV-2 Approved by the National Medical Products Administration of China and Their Application for Diagnosis of COVID-19

The on-going global pandemic of coronavirus disease 2019(COVID-19)caused by a novel coronavirus called severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has been underway for about 11 months.Through November 20,2020,51 detection kits for SARS-CoV-2 nucleic acids(24 kits),antibodies(25 kits),or antigens(2 kits)have been approved by the National Medical Products Administration of China(NMPA).Convenient and reliable SARS-CoV-2 detection assays are urgently needed worldwide for strategic control of the pandemic.In this review,the detection kits approved in China are summarised and the three types of tests,namely nucleic acid,serological and antigen detection,which are available for the detection of COVID-19 are discussed in detail.The development of novel detection kits will lay the foundation for the control and prevention of the COVID-19 pandemic globally.

Serologic Response to SARS-CoV-2 in COVID-19 Patients with Different Severity

The immense patient number caused by coronavirus disease 2019(COVID-19)global pandemic brings the urge for more knowledge about its immunological features,including the profile of basic immune parameters.In this study,eighty-eight reported COVID-19 patients in Wuhan were recruited from January to February,2020,including 32 severe/critical cases and56 mild/moderate cases.Their mean age was 56.43 years(range 17–83)and gender ratio(male/female)was 43:45.We tested SARS-CoV-2 RNA with commercial kits,investigated the level of serologic IgM and IgG antibodies against severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)using magnetic particle chemiluminescence immunoassays,and compared the results of serologic tests and nucleic acid test(NAT).Among 88 patients,95.45%were confirmed as positive by the combination of NAT and antibody test,which was significantly higher(P<0.001)than by single nucleic acid test(73.86%)or serologic test(65.91%).Then the correlation between temporal profile and the level of antibody response was analyzed.It showed that seroconversion started on day 5 after disease onset and IgG level was rose earlier than IgM.Comparison between patients with different disease severity suggested early seroconversion and high antibody titer were linked with less severe clinical symptoms.These results supported the combination of serologic testing and NAT in routine COVID-19 diagnosis and provided evidence on the temporal profile of antibody response in patients with different disease severity.

Washing-free chemiluminescence immunoassay for rapid detection of cardiac troponin Ⅰ in whole blood samples

Chemiluminescence immunoassay(CLⅠA) has always been a great challenge in detecting cardiac troponin Ⅰ(c Tn Ⅰ) in whole blood samples without centrifugation because of the interference of red blood cells and low sensitivity. Ⅰn this study, the antigens and erythrocytes in the blood were captured by the antibodies immobilized on the magnetic particles, recognized by another biotinconjugated c Tn Ⅰ antibody and detected by streptavidin/acridine aster-conjugated polychloromethylstyrene microspheres(PCMS). After magnetic separation, the supernatant was transferred and measured. No significant difference was noted between the c Tn Ⅰ concentrations of the serum samples,plasma samples and whole blood. The prepared PCMS provided more functional areas to conjugate streptavidin and acridinium ester, so the immunoassay has highly sensitive, the limits of blank at0.012 ng/mL, and functional sensitivity at 0.019 ng/mL with a CV of 20%, and 0.058 ng/mL with a CV of 10%. Total precision of any sample type ranged from 2.62%~5.67%. The assay was linear over the studied range of 0.01-50.00 ng/mL, and no hook effect was found when c Tn Ⅰ concentrations reached 1900 ng/mL. No significant interference was noted with the potential endogenous interfering substances. Compared with the commercial kit(Abbott assay kit), the correlation coefficient was 0.9859. A washing-free CLⅠA was established for the rapid detection of c Tn Ⅰ in human whole blood, using erythrocyte capture antibodies-conjugated magnetic nanoparticles for eliminating the influence of erythrocytes and PCMS for signal amplification, which showed great potential in clinical application.

N-(β-Carboxypropionyl)luminol as a new chemiluminescence label in immunoassay

A new chemilurninescence label N-(β-carboxypropionyl)luminol (CPL) was used to label sheep anti-human IgG (SaHIgG).The labeled antibody was stable and could be detected at least down to 10-17~10-16 mol.The molar incorporation ratio was estimated to be 0.26 mol of CPL per mol of SaHIgG.There were no apparent changes in the immunoreactivity of the labeled SaHIgG and in the quantum efficiency of the CPL after labeling.