Current Analytical Chemistry - Volume 21, Issue 6, 2025

Aptamer-based strategies have emerged as promising tools for the detection and treatment of COVID-19, offering advantages such as high specificity, sensitivity, and versatility. This systematic review aims to evaluate the effectiveness and innovation of aptamer-based approaches for COVID-19 detection and treatment.

Following the guidelines of the Cochrane Handbook for Systematic Reviews and the PRISMA 2020 guidelines, a systematic search was conducted across multiple databases up to 2024. The search included studies that utilized aptamers for the diagnosis or therapy of COVID-19. Screening and selection of studies were performed independently by two reviewers, with any disagreements resolved by a third reviewer. Data were extracted regarding study characteristics, aptamer details, and outcomes.

In our systematic review, 98 studies from an initial pool of 1541 records met the inclusion criteria for analysis. Aptamers, single-stranded DNA or RNA molecules with unique three-dimensional (3D) structures, were extensively explored for COVID-19 detection and treatment. Various aptamer-based assays, including electrochemical sensors, surface plasmon resonance (SPR) biosensors, and lateral flow assays, demonstrated high sensitivity and specificity in detecting SARS-CoV-2 in clinical samples such as saliva, nasal swabs, and wastewater. Several aptamer structures targeting viral proteins like the spike and nucleocapsid proteins were employed. Nucleic Acid Amplification Techniques (NAATs) utilizing aptamers, such as Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-based and Loop-mediated Isothermal Amplification (LAMP) assays, showed exceptional sensitivity in detecting viral genetic material. Aptamer-based therapeutic approaches showed potential by blocking viral protein activity or serving as delivery vehicles for therapeutic agents like small interfering RNAs (siRNAs). Despite their advantages, aptamer technologies face limitations such as susceptibility to nuclease degradation and rapid renal clearance, highlighting the need for further optimization.

Aptamer-based strategies present promising avenues for COVID-19 detection and treatment. These approaches offer advantages such as high sensitivity, specificity, and rapid detection, making them valuable tools in combating the COVID-19 pandemic. Further research and development are warranted to optimize aptamer-based strategies for widespread application in clinical settings.

Rodent pests cause significant damage to the national economy and human health in China. Rodent infertility control technology offers a new and less toxic approach to managing rodent pests. The use of a plant complex sterility agent has shown the potential to induce male infertility, but the molecular mechanism behind this effect remains unclear and requires further investigation.

Sixty Sprague Dawley (SD) rats were randomly assigned to control, low-dose (10 mg/kg of plant complex sterility agent containing shikonin and acetylstilbestrol), and high-dose (20 mg/kg of plant complex sterility agent) groups. The rats received intragastric administration of the agent for 30 days. Sperm count and testosterone levels were assessed to evaluate fertility. The protein interacting with C kinase 1 (PICK1) and Toll-like receptor 4 (TLR4) levels in the control group, low-dose group, and high-dose group were measured by immunohistochemistry (IHC) and Western Blotting (WB).

In comparison to the control group, both the sperm concentration (p < 0.05) and the levels of testosterone (p < 0.05), PICK1 (p < 0.05), and TLR4 (p < 0.05) were significantly decreased in a dose-dependent manner in the low dose and high dose groups. These changes were confirmed through microscopy, ELISA, IHC, and WB.

The plant complex sterility agent demonstrates potential in reducing sperm concentration and down-regulating testosterone levels. It likely exerts its effects by impairing male fertility in rats through the inhibition of PICK1 and TLR4 protein levels.

Environmental contamination of the air, water, soil, and food has become a threat to the continued existence of many plant and animal communities in the ecosystem. The chemically activated stem bark of Anonna senegalensis was examined for equilibrium sorption.

This study aimed to assess the adsorption of Cr⁶⁺ and Cu²⁺ onto Annona senegalensis carbon (ASC) according to the following parameters: pH, solution temperature, starting metal ion concentration, agitation duration, dose of adsorbent, particle size, and carbonization temperature using a simultaneous batch adsorption method. Pseudo-first order, pseudo-second order, intra-particle diffusion kinetic, Freundlich, Langmuir, Temkin, and Dubinin-Radushkevich isotherm models were all fitted using the equilibrium sorption data that were produced. Thermodynamic parameters of the adsorption studies were also evaluated.

The physicochemical analysis of ASC showed ash content of 7.21 ± 0.02%, moisture content of 11.73 ± 0.29%, and porosity of 0.99 ± 0.08 with bulk density of 0.18 g/cm³. The heavy metal-loaded scanning electron microscope (SEM) micrograph showed a filled pit, and the XRD diffractogram, as well as FTIR spectra, revealed peaks that were different from the raw spectra, implying functionalization. The sorption data gave optimum conditions of the adsorption process to be pH of 6, agitation time of 88 minutes, adsorbent dose of 2.5 g/g, initial metal ion concentration of 5 mg/L, temperature of 30°C, particle size of 0.154 mm and carbonization temperature of 400°C.

The Langmuir isotherm was found to give the best-fit conformation of all the models based on superior R² (R² ≥0.99). Dubinin-Radushkevich proved the mechanism to be physisorption. The pseudo-second-order kinetic model best fits the data with R² of 0.998 and 0.986 for Cr⁶⁺ and Cu²⁺. Thermodynamic results of the study revealed that ΔH^ᵒ for Cr⁶⁺ and Cu²⁺ were 32.78 and 27.14 KJ/mol and are all positive, implying an endothermic process and confirming the physisorption mechanism. The entropy change, ΔS^ᵒ, was also positive, revealing a high degree of disorderliness at the sorbate/sorbent interphase. The standard Gibbs free energy, ΔG^ᵒ, were all negative, showing spontaneity and feasibility.

This study presents the successful fabrication of composite membranes composed of polyvinyl alcohol (PVA) polymer blended with titanium dioxide (TiO2) nanoparticles and a combination of titanium dioxide/zirconium dioxide (TiO2/ZrO2) nanoparticles. The features of composite membranes were analyzed with a specific focus on comparing the characteristics of PVA/TiO2 and PVA/TiO2/ZrO2 composite membranes.

TiO2 and ZrO2 nanoparticles were prepared using the sol-gel method. PVA/TiO2 and PVA/TiO2/ZrO2 composite membranes were fabricated utilizing the solution casting method. A controlled method of production of nanoparticles and their uniform dispersion inside the polymer matrix are the key components contributing to the success of this approach. TiO2 and ZrO2 nanoparticles and their composite membranes were characterized through various characterization methods encompassing X-ray diffraction (XRD) study, UV-visible absorption spectroscopy, photoluminescence (PL) spectroscopy, transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectroscopy and atomic force microscopy (AFM) analysis.

The XRD study revealed improved crystallinity in composite membranes. The PVA/TiO2/ZrO2 membrane possessed a greater level of crystallinity than the PVA/TiO2 membrane. The composite membranes exhibited enhanced absorption and PL behaviour. The FTIR spectra revealed the creation of a charge-transfer complex among the PVA, TiO2 and ZrO2. The AFM study indicates that surface roughness increases after doping.

Good concurrence is established between grain size calculated by XRD and TEM. PVA/TiO2/ZrO2 exhibits more improved characteristics than PVA/TiO2 because of the composite versatile properties resulting from the combining of two inorganic structural components with polymer. Such characteristics render it an appealing option for optical and optoelectronic device applications.

The continuously growing number of commercial Lawsonia inermis (henna) powders and the wide variability of their quality necessitate verifying as well as controlling their level of lawsone, the main active ingredient. The purpose of this study is to examine the effect of drying on the level of lawsone.

The leaves of henna were dried at different temperatures (40°C, 50°C, and 60°C) with both modes (air and ultrasound). We extracted lawsone from leaves by a Soxhlet extractor using methanol and water as solvents, respectively. This natural pigment was isolated, purified, and analyzed by thin-layer chromatography (TLC), high-pressure liquid chromatography (HPLC), and ultra-violet (UV) spectrophotometer.

The drying temperature highly affected the extraction yield (Re). Therefore, drying henna leaves at low temperatures allows for a higher yield of lawsone extracts.

We recommend ultrasonically assisted drying of henna leaves to facilitate both the reduction of drying temperatures in order to conserve energy as well as the increase of the yield of lawsone extraction.

Since the mid-20th century, polychlorinated biphenyls (PCBs) have emerged as one of the foremost anthropogenic organic pollutants in aquatic environments. Microphytobenthic algae of the genus Cylindrotheca have been recurrently employed in laboratory experiments to assess sediment toxicity. Recently, a novel strain of benthic diatoms belonging to the genus Cylindrotheca has been identified and characterized from PCB-contaminated sediments in the coastal region of Sevastopol Bay (Black Sea). This species of algae has high biomass productivity, the ability to synthesize fucoxanthin, and a variety of fatty acids. Cylindrotheca closterium is capable of metabolizing organic pollutants in bottom sediments.

The objective of the study was to investigate the effects of PCBs on the growth patterns and physiological responses of C. closterium through a 9-day experiment, subjecting the microalgae to varying concentrations of PCBs ranging from 0.0003 to 100 mg/L.

The experiments revealed that C. closterium could grow in environments containing concentrations of PCBs ranging from 0.0003 to 10 mg/L, indicating its resilience to moderate levels of PCB exposure. Additionally, adaptive biochemical processes were observed in C. closterium under PCB exposure. Notably, on the sixth day of the experiment, the culture transitioned into a stationary growth phase, accompanied by significant increases in total lipid content by 1.6 times and fucoxanthin by 4.6 times compared to the control. However, a pronounced decrease in culture growth was observed at a PCB concentration of 100 mg/L, coinciding with reductions in total lipid and fucoxanthin content, suggesting a tolerance threshold of C. closterium between 10 and 100 mg/L PCB concentrations. Furthermore, alterations in the fatty acid profile of C. closterium were noted, characterized by a decrease in polyene content and an increase in monoene fatty acids, under PCB exposure.

The study underscores the resilience of C. closterium to moderate PCB concentrations and highlights the complex physiological responses and adaptive mechanisms initiated in response to PCB exposure. The findings contribute to understanding the toxic effects of PCBs on C. closterium and provide insights into potential mechanisms underlying these effects.

PYX-106 is a fully human monoclonal antibody (mAb), targeting sialic acid binding immunoglobulin-like lectin-15 (Siglec-15), an immunosuppressive agent with widespread expression across various tumor types.

To facilitate the evaluation of immunogenicity for PYX-106 in human serum, a validated method was established to enable the detection (screening, confirmatory, and titration) of antibodies to PYX-106 in human serum samples.

The Screening Cut-Point Factor (SCPF), Confirmatory Cut-Point (CCP), and Titration Cut-Point Factor (TCPF) were found to be 1.51, 26.9%, and 1.86, respectively. Sensitivity was determined to be 1.81 ng/mL in the screening assay and 1.25 ng/mL in the confirmatory assay. Low Positive Control (LPC) was set at 6.00 ng/mL, and High Positive Control (HPC) was set at 1000 ng/mL. The drug tolerance was up to 500 µg/mL at the HPC level, up to 241 µg/mL at the ADA 100 ng/mL level, and up to 38.9 µg/mL at the LPC level. The intra-assay percent coefficient of variation (%CV) was ≤ 2.1% for Positive Controls (PCs) in the screening assay and ≤ 1.0% for PCs in the confirmatory assay. The inter-assay %CV was ≤ 15.3% for PCs in the screening assay and ≤ 2.1% for PCs in the confirmatory assay. No hook effect, hemolysis effect, lipemia effect, or bilirubin interference was found in this ADA method. Anti-PYX-106 antibodies were found stable in human serum for at least 23 hours 51 minutes at room temperature or after six freeze/thaw cycles.

Anti-PYX-106 ADA bioanalytical assay validation was reported for the first time in any biological matrix. This ADA method has been successfully applied to human sample analysis to support a clinical study.

This study aimed to carry out the green synthesis of palladium nanoparticles (Pd NPs) using the aqueous leaves extract of Eclipta alba. The appearance of a characteristic surface plasmon resonance peak at 410 nm confirmed the synthesis of Pd NPs.

The average particle sizes of 13 nm were observed by using the leaf concentrations of 10 mL with a certain amount of PdCl2 (0.001 M) at 25°C. The Pd NPs, as synthesized under the optimized conditions (10 mL extract + 60°C + 0.001 M PdCl2), were spherical in shape, small in size, and uniformly distributed, as depicted by HR-TEM images.

FTIR, XRD, DLS, and zeta potential further confirmed the formation of Pd NPs. The Pd NPs synthesized at optimized conditions exhibited strong catalytic activity in dye Eosin yellow, Rose Bengal, Tartrazine, and Ponceau S degradation by discoloration of dyes in 3 hrs. The removal of all dyes by the Pd NPs was optimized by varying specific operating parameters, such as initial dye concentration, solution pH, irradiation time, and temperature.

This high activity of Pd NPs may be due to their small size, high dispersion, and surface-capping phytochemicals.