An ultra-sensitive electrochemical biosensor using the Spike protein for capturing antibodies against SARS-CoV-2 in point-of-care.

This work presents an innovative ultra-sensitive biosensor having the Spike protein on carbon-based screen-printed electrodes (SPEs), for monitoring in point-of-care antibodies against SARS-CoV-2, a very important tool for epidemiological monitoring of COVID-19 infection and establishing vaccination schemes. In an innovative and simple approach, a highly conductive support is combined with the direct adsorption of Spike protein to enable an extensive antibody capture. The high conductivity was ensured by using carboxylated carbon nanotubes on the carbon electrode, by means of a simple and quick approach, which also increased the surface area. These were then modified with EDC/NHS chemistry to produce an amine layer and undergo Spike protein adsorption, to generate a stable layer capable of capturing the antibodies against SARS-CoV-2 in serum with great sensitivity. Electrochemical impedance spectroscopy was used to evaluate the analytical performance of this biosensor in serum. It displayed a linear response between 1.0 â€‹pg/mL and 10 â€‹ng/mL, with a detection limit of ∼0.7 â€‹pg/mL. The analysis of human positive sera containing antibody in a wide range of concentrations yielded accurate data, correlating well with the reference method. It also offered the unique ability of discriminating antibody concentrations in sera below 2.3 â€‹µg/mL, the lowest value detected by the commercial method. In addition, a proof-of-concept study was performed by labelling anti-IgG antibodies with quantum dots to explore a new electrochemical readout based on the signal generated upon binding to the anti-S protein antibodies recognised on the surface of the biosensor. Overall, the alternative serologic assay presented is a promising tool for assessing protective immunity to SARS-CoV-2 and a potential guide for revaccination.

Molecular Imprinting on Nanozymes for Sensing Applications.

As part of the biomimetic enzyme field, nanomaterial-based artificial enzymes, or nanozymes, have been recognized as highly stable and low-cost alternatives to their natural counterparts. The discovery of enzyme-like activities in nanomaterials triggered a broad range of designs with various composition, size, and shape. An overview of the properties of nanozymes is given, including some examples of enzyme mimics for multiple biosensing approaches. The limitations of nanozymes regarding lack of selectivity and low catalytic efficiency may be surpassed by their easy surface modification, and it is possible to tune specific properties. From this perspective, molecularly imprinted polymers have been successfully combined with nanozymes as biomimetic receptors conferring selectivity and improving catalytic performance. Compelling works on constructing imprinted polymer layers on nanozymes to achieve enhanced catalytic efficiency and selective recognition, requisites for broad implementation in biosensing devices, are reviewed. Multimodal biomimetic enzyme-like biosensing platforms can offer additional advantages concerning responsiveness to different microenvironments and external stimuli. Ultimately, progress in biomimetic imprinted nanozymes may open new horizons in a wide range of biosensing applications.

First record of Systelloderes (Hemiptera: Heteroptera: Enicocephalidae) from Ecuador with a list of Ecuadorian Enicocephalomorpha.

The genus Systelloderes Blanchard, 1852 (Hemiptera: Heteroptera: Enicocephalomorpha: Enicocephalidae), has a nearly cosmopolitan distribution, with the greatest species richness being found in humid tropical and subtropical forests, but species are also present in humid microhabitats of temperate and arid zones (Wygodzinsky Schmidt 1991). In the Eastern Hemisphere species of Systelloderes occur in continental Africa (22 species, see Villiers 1969; 1976; Maldonado 1988; Banar 2008); Madagascar (Systelloders milloti Villiers, 1952); New Zealand (see Stys 1970, 2002) and New Caledonia (Systelloders loebli Stys Banar, 2007). Two species (S. capillicornis Bergroth, 1918 from Luzon and S. aetherius Bergroth, 1916 from Queensland) originally described as Systelloderes belong to the genus Henschiella Horváth, 1888 (P. Stys, unpublished data). As is frequently the case with Enicocephalomorpha, many species of Systelloderes remain to be described, especially from the Afrotropical, Neotropical and Oriental Regions. There are 13 described Systelloderes species from North and Central America (Wygodzinsky Schmidt 1991). To date, there are only six described species of Systelloderes from South America: two from Venezuela, and by a single species from Bolivia, Brazil, Chile and Peru each. There are very few additional records of Systelloderes in the New World tropics, including the works of Wolda (1975) and Ospina-Bautista (2018) on Colombia, Parker et al. (2012) on Peru, and Maestre et al. (2001) from Brazil.

Smoking-related attitudes and their sociodemographic correlates among Mexican-origin adult smokers.

The purpose of the study was to describe smoking-related knowledge and attitudes of a specific group of Latino smokers, and to identify sociodemographic correlates. This study is one of the few to provide information about smoking-related psychosocial variables and their correlates among a Latino subgroup. A survey was administered to a volunteer sample of adult smokers of Mexican-origin (n = 278) to assess their sociodemographic characteristics, and smoking-related knowledge and attitudes. Measures of smoking-related attitudes targeted six constructs: self-efficacy for quitting smoking, anticipated outcomes, intentions to quit, normative expectations, social support, and barriers to quitting. Smoking/cessation knowledge was assessed with a 14 item test. This sample of smokers had high knowledge and positive attitudes about quitting smoking. Several sociodemographic variables were associated with attitudinal knowledge variables, although no consistent pattern of association was seen. Results underscore the complexity between smoking-related attitudes and sociodemographic factors, and are discussed in terms of implications for culturally-tailored interventions.