A detection method based on an electrochemical aptasensor has been developed as an alternative fast, portable, simple, inexpensive, and high-accuracy detection method for detecting the SARS-CoV-2 Spike Receptor Binding Domain (spike RBD).

A nanocomposite of natural silica and ceria was synthesized to modify a screen-printed carbon electrode (SPCE) to develop an aptasensor to detect epithelial sodium channel (ENaC) protein in urine as a biomarker of hypertension. The method steps were the synthesis of natural silica-ceria nanocomposite using the hydrothermal method, obtaining of natural silica nanoparticles from the extraction of alkaline silica sand and ceria nanoparticles from cerium nitrate, modification of SPCE/natural silica-ceria, immobilization of aptamer through streptavidin-biotin, and detection of ENaC protein conc­entration. Box-Behnken’s design was employed to determine the optimal con­ditions of aptamer concentration (0.5 μg mL-1), streptavidin incubation time (30 min), and aptamer incubation time (1 hour), respectively. Differential pulse voltam­metry (DPV) characterization of the developed electrochemical aptasensor revealed that the [Fe(CN)6]3-/4- redox peak current increased from 3.190 to 9.073 μA, with detection and quantification limits of 0.113 and 0.343 ng mL-1, respectively. The method is proven as a simple and rapid method to monitor ENaC levels in urine samples.

Tropical diseases (TDs) are among the leading cause of mortality and fatality globally. The emergence and reemergence of TDs continue to challenge healthcare system. Several tropical diseases such as yellow fever, tuberculosis, cholera, Ebola, HIV, rotavirus, dengue, and malaria outbreaks have led to endemics and epidemics around the world, resulting in millions of deaths. The increase in climate change, migration and urbanization, overcrowding, and other factors continue to increase the spread of TDs. More cases of TDs are recorded as a result of substandard health care systems and lack of access to clean water and food. Early diagnosis of these diseases is crucial for treatment and control. Despite the advancement and development of numerous diagnosis assays, the healthcare system is still hindered by many challenges which include low sensitivity, specificity, the need of trained pathologists, the use of chemicals and a lack of point of care (POC) diagnostic. In order to address these issues, scientists have adopted the use of CRISPR/Cas systems which are gene editing technologies that mimic bacterial immune pathways. Recent advances in CRISPR-based biotechnology have significantly expanded the development of biomolecular sensors for diagnosing diseases and understanding cellular signaling pathways. The CRISPR/Cas strategy plays an excellent role in the field of biosensors. The latest developments are evolving with the specific use of CRISPR, which aims for a fast and accurate sensor system. Thus, the aim of this review is to provide concise knowledge on TDs associated with mosquitoes in terms of pathology and epidemiology as well as background knowledge on CRISPR in prokaryotes and eukaryotes. Moreover, the study overviews the application of the CRISPR/Cas system for detection of TDs associated with mosquitoes.

Gold silica nanocomposite-based biosensors are performing well in sensor technology for biosensor development. Due to this biosensor has good selectivity, excellent conductivity, large surface area, efficient enhancement of electron transfer between enzymes and electrodes and good biocompatibility. Therefore, gold silica nanocomposite can be an ideal matrix for immobilization of biomolecules. This review describes the method of synthesizing gold silica nanocomposites and their characterization, interaction with biomolecules and application of gold silica nanocomposites in electrochemical biosensors.

This study aims to optimize the epithelial sodium channel (ENaC) electrochemical aptasensor with the Box-Behnken experimental design. ENaC is a protein that plays a role in sodium ion transport in several epithelial tissues and is associated with hypertension. The ENaC protein aptamer is held in place in the electrochemical aptasensor by a modified screen-printed carbon electrode (SPCE) of silica-ceria composite (SiO2-CeO2). The unique structure of a silica matrix with high biocompatibility can form composites through a hydrothermal process. The Box-Behnken (BBD) experimental design is an efficient optimization method of factors that affect the experiment at three levels. The FTIR results of the silica-ceria composites were 549.35 cm-1 (Ce-O), 1095.3 cm-1 (Si-O-Si), and 491.28 cm-1 (Si-O). Meanwhile, SPCE/silica-ceria characterized by differential pulse voltammetry (DPV) showed an increase in peak current [Fe(CN)6]3-/4- from 3.190 μA to 9.073 μA. Three experimental factors, aptamer concentration, streptavidin incubation time, and aptamer incubation time, were optimized with BBD and obtained at 0.5 μg.mL-1, 30 minutes, and 1 hour. The optimum conditions observed resulted in a selective current response for ENaC protein detection. The optimization results can be applied to aptamer-based ENaC protein detection in samples.

Fast, sensitive, and easy-to-use methods for detecting DNA related to food adulteration, health, religious, and commercial purposes are evolving. In this research, a label-free electrochemical DNA biosensor method was developed for the detection of pork in processed meat samples. Gold electrodeposited screen-printed carbon electrodes (SPCEs) were used and characterized using SEM and cyclic voltammetry. A biotinylated probe DNA sequence of the Cyt b S. scrofa gene mtDNA used as a sensing element containing guanine substituted by inosine bases. The detection of probe-target DNA hybridization on the streptavidin-modified gold SPCE surface was carried out by the peak guanine oxidation of the target using differential pulse voltammetry (DPV). The optimum experimental conditions of data processing using the Box–Behnken design were obtained after 90 min of streptavidin incubation time, at the DNA probe concentration of 1.0 µg/mL, and after 5 min of probe-target DNA hybridization. The detection limit was 0.135 µg/mL, with a linearity range of 0.5–1.5 µg/mL. The resulting current response indicated that this detection method was selective against 5% pork DNA in a mixture of meat samples. This electrochemical biosensor method can be developed into a portable point-of-care detection method for the presence of pork or food adulterations.