Development and Validation of an Ultrasensitive Procalcitonin Sandwich Immunoassay

Role of biomarkers in the diagnosis of invasive aspergillosis in immunocompromised patients

BACKGROUND

Invasive aspergillosis is one of the important causes of infection in immunocompromised patients. This study aimed to evaluate the roles of biomarkers in the diagnosis of invasive aspergillosis and their relationship with antifungal stewardship programs.

METHODS

190 sera from 52 immunocompromised patients and volunteer individuals were included in this study. 18 immunocompromised volunteers without IA and 34 patients with probable and proven aspergillosis according to the European Organization for Research and Treatment of Cancer and the Mycoses Study Group consensus definitions were entered in this study. The respective sera were evaluated for procalcitonin, soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) levels; white blood cells count (WBC) count, C reactive protein (CRP), lactate dehydrogenase (LDH), and erythrocyte sedimentation rate (ESR) values. Demographic data and clinical characteristics of patients were extracted from their files.

RESULTS

The male-to-female ratio and mean age of patients were 22/12 and 38.9 years, respectively. The hematologic disorder was the most predisposing factor (29/34, 85.3%). Sensitivity of biomarkers for diagnosis of invasive aspergillosis was 70.6% (cut off value > 190 pg/mL for sTREM-1, 71% (cut off value > 260 pg/mL) for PCT, 85.3% (cut off value > 193 U/L) for LDH, 94.1% (cut off value > 8 mg/l) for CRP, 64.7% (cut off value < 5200 cells/ml) for WBC, and 85.3% (cut off value > 23 mm/h) for ESR. Twelve patients died, with significantly increased sTREM-1 levels and decreased WBC count in them.

CONCLUSION

According to our data, evaluation of the biomarkers can help in the diagnosis, management, and prediction of the severity of Aspergillus infection, and the rational use of antifungal agents in immunocompromised patients.

Simultaneous Quantitative Detection of IL-6 and PCT Using SERS magnetic immunoassay with sandwich structure

Sepsis is a systemic inflammatory response syndrome caused by infection. The mortality rate is as high as 30%-50%. Early diagnosis and treatment can significantly improve the mortality of patients with sepsis. Therefore, we have developed a SERS-based magnetic immunoassay method that uses the principle of sandwich method to quantitatively detect Interleukin 6 (IL-6) and Procalcitonin (PCT). In this article, two different Raman reporter molecules are embedded in the middle of the Au@Ag shell and coupled with the tracer antibody to form a SERS immunoprobe. Biotin was coupled with capture antibody to form a sandwich structure when participating in the immune response. Streptavidin and biotin systems have extremely high binding affinity. The sandwich structure is quickly captured by SA magnetic beads and then applied with a magnetic field to enrich the magnetic beads. Finally, simultaneous quantitative detection is achieved by the intensity of the two Raman reporter characteristic peaks on the solution magnetic beads. IL-6 and PCT showed a good relationship between 0-1000 pg ml^-1and 0-20 ng ml^-1, respectively, and the limits of detection were 0.54 pg ml^-1and 0.042 ng ml^-1, respectively. The recovery rate was between 89.8% and 104.2%, both intra-assay and inter-assay CV were ≤20%. No cross-reaction with C-reactive protein (100μg ml^-1), showing good specificity. This method provides a new technical reference for the clinical detection of sepsis biomarkers.

An Optical Sensor for Dengue Envelope Proteins Using Polyamidoamine Dendrimer Biopolymer-Based Nanocomposite Thin Film: Enhanced Sensitivity, Selectivity, and Recovery Studies

This paper proposes a novel idea to enhance the sensitivity and selectivity of surface plasmon resonance (SPR) optical sensor for detection of dengue virus type-2 envelope proteins (DENV-2 E-proteins) using polyamidoamine (PAMAM) dendrimer biopolymer-based nanocomposite thin film. For this purpose, two ranges of DENV-2 E-protein concentrations, i.e., 0.000008-0.0001 nM and 0.00008-0.005 nM were evaluated, and the lowest detectable concentration was achieved at 0.00008 nM. The incorporation of PAMAM dendrimer-based nanocomposite thin film with an SPR sensor exhibited a significant increase in sensitivity and binding affinity to a lower range DENV-2 E-protein concentrations. Moreover, the proposed sensor displayed good selectivity towards DENV-2 E-proteins and have an average recovery of 80-120%. The findings of this study demonstrated that PAMAM dendrimer-based nanocomposite thin film combined with SPR sensor is a promising diagnostic tool for sensitive and selective detection of DENV-2 E-proteins.

Health Risk Assessment of Metals in Selected Drinks from Abeokuta, Southwestern Nigeria

The present study assessed the human health risk of metals in selected drinks from Abeokuta, southwestern Nigeria. Fifteen different brands of drinks (alcoholic, non-alcoholic, herbal and non-herbal) were purchased from notable markets in Abeokuta between June and August, 2018. A total of sixty drink samples were analysed for metals using atomic absorption spectrophotometry. Data were subjected to descriptive and inferential statistics. Human health risks were assessed for cancer risk (CR) and non-carcinogenic indices of hazard quotient (HQ) and hazard index (HI). Results showed acidic medium for most of the samples ranging from 3.12 ± 0.29 to 6.14 ± 0.17. The highest concentrations of Fe (5.53 ± 2.81 mg/L) and Mn (6.63 ± 8.33 mg/L) were found in Kunnu and Zobo, respectively. The HQ and HI values of Cu in bottled water indicated non-carcinogenic adverse effects, while the CR of Co in bottled water and bitters demonstrated carcinogenic effects. Regular monitoring of metals in drinks from the study area is recommended.

Time-Resolved Digital Immunoassay for Rapid and Sensitive Quantitation of Procalcitonin with Plasmonic Imaging

Timely diagnosis of acute diseases improves treatment outcomes and saves lives, but it requires fast and precision quantification of biomarkers. Here, we report a time-resolved digital immunoassay based on plasmonic imaging of binding of single nanoparticles to biomarkers captured on a sensor surface. The real-time and high contrast of plasmonic imaging lead to fast and precise counting of the individual biomarkers over a wide dynamic range. We demonstrated the detection principle, evaluated the performance of the method using procalcitonin (PCT) as an example, and achieved a limit of detection of ∼2.8 pg/mL, dynamic range of 4.2-12500 pg/mL, for a total detection time of ∼25 min.

Development and evaluation of an ultrasensitive free VEGF-A immunoassay for analysis of human aqueous humor

Aim: Novel bifunctional VEGF-A neutralizing therapies are being developed for the treatment of retinal vascular diseases such as age-related macular degeneration and diabetic retinopathy. In developing new therapeutic drugs, only small aqueous humor sample volumes are available for analyzing several parameters. Highly sensitive detection methods must be applied in analyzing VEGF-A levels in ocular fluids in order to demonstrate VEGF-A suppression following drug administration. Experimental: A highly sensitive immunoassay for VEGF-A was developed on the single molecule array (Simoa) platform, and validated before being used for the analysis of clinical aqueous humor samples from patients treated with anti-VEGF-A therapeutics. Results: This highly sensitive immunoassay allows the detection of baseline VEGF-A levels and suppression effects after drug administration, even in sample volumes as low as 12 μl. Conclusion: The Simoa VEGF-A assay is a valuable tool for the reliable monitoring of VEGF-A suppression after intravitreal administration of anti-VEGF-A drugs.