Derivatization of γ-Amino Butyric Acid Analogues for Their Determination in the Biological Samples and Pharmaceutical Preparations: A Comprehensive Review

Clinical significance of GABA, NSE, and miR-155 expression in patients with post-stroke epilepsy

This study investigated the clinical predictive value of cerebrospinal fluid (CSF) γ-aminobutyric acid (GABA) and serum neuron-specific enolase (NSE) and microRNA-155 (miR-155) for post-stroke epilepsy (PSE) in patients with cerebral infarction (CI). A total of 69 CI patients with PSE and 84 with non-post-stroke epilepsy (N-PSE) were retrospectively enrolled, with their clinical baseline data (CI type) and the National Institute of Health Stroke Scale (NIHSS) score collected. CSF GABA and serum NSE and miR-155 expression levels were determined, with their clinical value further assessed. The results showed that the proportions of patients with cardiogenic CI, multiple infarcts, and cortical involvement and NIHSS score in PSE patients were higher than those in N-PSE patients. CSF GABA was lowly expressed and serum NSE and miR-155 were highly expressed in PSE patients. The NIHSS score negatively correlated with GABA and positively correlated with NSE and miR-155. GABA [area under the curve (AUC) = 0.906], NSE (AUC = 0.908), miR-155 (AUC = 0.862) and their combined detection (AUC = 0.963) all had certain value in the occurrence of PSE in CI patients, with their combined detection showing higher AUC than that of single detection. Briefly, CSF GABA was reduced while serum NSE and miR-155 were elevated in PSE patients. GABA and NSE combined with miR-155 had high diagnostic value for PSE occurrence in CI patients. Lowly-expressed GABA or highly-expressed NSE and miR-155 were independent risk factors for PSE in CI patients, which could provide effective guidance for the clinical diagnosis and management of PSE.

A new molecularly imprinted polymer electrochemical sensor based on CuCo2 O4 /N-doped CNTs/P-doped GO nanocomposite for detection of 25-hydroxyvitamin D3 in serum samples

25-Hydroxyvitamin D₃ as a main circulating metabolite of vitamin D is usually measured in serum to evaluate the vitamin D status of humans. So, developing an accessible, fast response, sensitive, and selective detection method for 25-hydroxyvitamin D₃ is highly important. In this study, we designed a sensitive and selective electrochemical sensor based on the modification of glassy carbon electrode by nanocomposite of CuCo₂ O₄ /nitrogen-doped carbon nanotubes and phosphorus-doped graphene oxide. Then 25-hydroxyvitamin D₃ -imprinted polypyrrole was coated on the electrode surface through electropolymerization. Moreover, ferricyanide was used as a mediator for the creation of a readable signal, which was considerably decreased after rebinding of 25-hydroxyvitamin D₃ on the electrode. The proposed sensor successfully detected 25-hydroxyvitamin D₃ in the range of 0.002-10 μM, with a detection limit of 0.38 nM, which was highly lower than deficiency concentration (20 ng/ml; 49.92 nM). Finally, the proposed sensor was checked for detection of 25-hydroxyvitamin D3 in serum samples with recovery in the range of 80%-106.42%. The results demonstrated the applicability of the designed sensor for the detection of 25-hydroxyvitamin D₃ in biological samples.

Aptamers for SARS-CoV-2: Isolation, Characterization, and Diagnostic and Therapeutic Developments

The SARS-CoV-2 virus and COVID-19 pandemic continue to demand effective diagnostic and therapeutic solutions. Finding these solutions requires highly functional molecular recognition elements. Nucleic acid aptamers represent a possible solution. Characterized by their high affinity and specificity, aptamers can be rapidly identified from random-sequence nucleic acid libraries. Over the past two years, many labs around the world have rushed to create diverse aptamers that target two important structural proteins of SARS-CoV-2: the spike (S) protein and nucleocapsid (N) protein. These have led to the identification of many aptamers that show real promise for the development of diagnostic tests and therapeutic agents for SARS-CoV-2. Herein we review all these developments, with a special focus on the development of diverse aptasensors for detecting SARS-CoV-2. These include electrochemical and optical sensors, lateral flow devices, and aptamer-linked immobilized sorbent assays.