The disease caused by SARS-CoV-2, coronavirus disease 2019 (COVID-19), has led to a global pandemic with tremendous mortality, morbidity, and economic loss. The current lack of effective vaccines and treatments places tremendous value on widespread screening, early detection, and contact tracing of COVID-19 for controlling its spread and minimizing the resultant health and societal impact. Bioanalytical diagnostic technologies have played a critical role in the mitigation of the COVID-19 pandemic and will continue to be foundational in the prevention of the subsequent waves of this pandemic along with future infectious disease outbreaks. In this Review, we aim at presenting a roadmap to the bioanalytical testing of COVID-19, with a focus on the performance metrics as well as the limitations of various techniques. The state-of-the-art technologies, mostly limited to centralized laboratories, set the clinical metrics against which the emerging technologies are measured. Technologies for point-of-care and do-it-yourself testing are rapidly emerging, which open the route for testing in the community, at home, and at points-of-entry to widely screen and monitor individuals for enabling normal life despite of an infectious disease pandemic. The combination of different classes of diagnostic technologies (centralized and point-of-care and relying on multiple biomarkers) are needed for effective diagnosis, treatment selection, prognosis, patient monitoring, and epidemiological surveillance in the event of major pandemics such as COVID-19.
Rapid, ultrasensitive, and specific detection and identification of bacteria in unprocessed clinical specimens is critically needed to enable point-of-care diagnosis of infectious diseases. However, existing systems require sample processing and/ or analyte enrichment for direct bacterial analysis in clinical samples, which significantly adds to the assay time and complexity. Herein, we integrate RNA-cleaving DNAzymes specific to Escherichia coli (E. coli) and programmed for electrochemical signal transduction, multifunctional microgel magnetic beads for immobilizing the DNAzyme into a hydrated and three-dimensional scaffold, and hierarchical electrodes for ultrasensitive electrochemical readout to achieve rapid bacterial analysis in undiluted and unprocessed urine collected from symptomatic patients suspected of having urinary tract infections (UTIs). The microgel magnetic bead assay enables highly efficient conjugation and hydration of the immobilized DNAzymes, resulting in low limits-of-detection of 6 CFU/mL in buffer and 138 CFU/mL in unprocessed urine with high specificity against multiple urinary pathogens within a 1 hour assay time. The assay successfully identifies which patients are infected with E. coli as the causative organism for their UTI symptoms, indicating the clinical relevance of this assay.
Hepatocellular carcinoma (HCC) surveillance lacks a reliable biomarker. Alpha-fetoprotein (AFP) is the most widely used. However, not all HCCs secrete AFP. AFP may be elevated with cirrhosis in the absence of HCC. Serum alpha-L-fucosidase (AFU) and squamous cell carcinoma antigen-immunoglobulin M complex (SCCA-IgM) were found to be useful markers in diagnosing HCC. SCCA-IgM and AFU were assessed by ELISA technique; AFP was measured by enzyme chemiluminescence in serum of 40 patients with HCC, 30 patients with liver cirrhosis, and 20 healthy control participants to compare their accuracy in early diagnosis of HCC. Serum SCCA-IgM and AFU levels were significantly elevated in HCC group compared to cirrhotic group (P value<0.001 and <0.001, respectively). Receiver operating characteristic curve showed the optimal cutoff value for SCCA-IgM was 233 AU/ml with sensitivity 87.5% and specificity 66% and for AFU was 25 U/L with sensitivity 87.5% and specificity 98%. AFP cutoff value was 48 ng/mL with sensitivity of 70% and specificity of 53.3%. The simultaneous determination of AFP and SCCA-IgM activity increased the sensitivity to 92.5% and specificity to 62.1%. There were positive significant correlations between SCCA-IgM and each of AFU (r=0.296, P=0.005) and AFP (r=0.284, P=0.007) and no correlation between AFP and AFU. All markers did not correlate with the tumor size or affected by the Child score. The significant difference between SCCA-IgM and AFU levels among HCC and cirrhotic patients suggests their use as potential diagnostic tools and allows identifying a new group of HCC patients even in the absence of elevated AFP.
Vitamin D is getting more attention everyday due to its importance in maintaining bone and calcium homeostasis, cellular proliferation, differentiation and immune response. Vitamin D is derived from diet or elicited in the skin by the activation of 7-dehydrocholesterol, which is an inert molecule that must be activated by ultraviolet light to form pre-vitamin D3. Recent studies connected the gene encoding for vitamin D (VDR) to the genetic control of bone mass and other diseases. As VDR SNPs have been associated with several disorders and diseases, it's important to investigate the allelic and genotypic distribution among populations. The aim of this study is to determine the frequency of rs731236 (Taq1) and rs2228570 (Fok1) variants in healthy Emirati individuals and compare their genotype and allele distribution with other populations. In this study 282 (female, 187; male, 95) unrelated healthy UAE nationals were involved. Two hundreds and eight two DNA samples been collected to genotype rs731236 (Taq1) and rs2228570 (Fok1) VDR SNPs. Our results indicate that the distribution of the alleles and genotypes of rs731236 (Taq1) and rs2228570 (Fok1) vary considerably in different populations. In the Emirati population the distribution of rs731236 (Taq1) and rs2228570 (Fok1) were AA 38%, AG 42%, GG 20% and AA 27%, AG 42%, GG 31% respectively. The Emirati population genotype and allele distribution of rs731236 (Taq1) and rs2228570 (Fok1) had no difference with Caucasians from USA and France. However, there was significant difference with Asian populations.
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