Jacqueline Soto‐Sánchez

Aptamers are single-stranded DNA or RNA sequences with a unique three-dimensional structure that allows them to recognize a particular target with high affinity. Although their specific recognition activity could make them similar to monoclonal antibodies, their ability to bind to a large range of non-immunogenic targets greatly expands their potential as tools for diagnosis, therapeutic agents, detection of food risks, biosensors, detection of toxins, drug carriers, and nanoparticle markers, among others. One aptamer named Pegaptanib is currently used for treating macular degeneration associated with age, and many other aptamers are in different clinical stages of development of evaluation for various human diseases. In the area of parasitology, research on aptamers has been growing rapidly in the past few years. Here we describe the development of aptamers raised against the main protozoan parasites that affect hundreds of millions of people in underdeveloped and developing countries, remaining a major health concern worldwide, i.e. Trypanosoma spp., Plasmodium spp., Leishmania spp., Entamoeba histolytica, and Cryptosporidium parvuum. The latest progress made in this area confirmed that DNA and RNA aptamers represent attractive alternative molecules in the search for new tools to detect and treat these parasitic infections that affect human health worldwide.

Parasitic diseases are a public health problem, especially in developing countries where millions of people are affected every year. Current treatments have several drawbacks: emerging resistance to the existing drugs, lack of efficacy, and toxic side effects. Therefore, new antiparasitic drugs are urgently needed to treat and control diseases that affect human health, such as malaria, Chagas disease, leishmaniasis, amebiasis, giardiasis schistosomiasis, and filariasis, among others. Quinoxaline is a compound containing a benzene ring and a pyrazine ring. The oxidation of both pyrazine ring nitrogens allows the obtention of quinoxaline 1,4-di-N-oxides (QdNOs) derivatives. By modifying the chemical structure of these compounds, it is possible to obtain a wide variety of biological properties. This review investigated the activity of quinoxaline derivatives and QdNOs against different protozoan parasites and helminths. We also cover the structure-activity relationship (SAR) and summarize the main findings related to their mechanisms of action from published works in recent years. However, further studies are needed to determine specific molecular targets. This review aims to highlight the new development of antiparasitic drugs with better pharmacological profiles than current treatments.

We created a glucose oxidase (GOx) working electrode on a silicon-on-insulator (SOI) wafer for glucose sensing. The SOI wafer was electrically connected to a copper wire, and the GOx was immobilized onto the hydrophilized SOI surface via silanization with aminopropyltriethoxysilane and glutaraldehyde. Electrochemical analysis (i.e., cyclic voltammetry) was employed to identify the sensing mechanism and to evaluate the performance of these SOI–GOx glucose sensors. The response of the SOI–GOx working electrode was significantly higher in the presence of oxygen than that without oxygen, indicating that a hydrogen peroxide pathway dominated in our SOI–GOx electrode. The height of cathodic peaks increased linearly with the increase of glucose concentrations up to 15 mM. The SOI–GOx working electrode displayed good stability after more than 30 cycles. On the 133rd day after the electrode was made, although the response of the SOI–GOx electrode dropped to about one-half of its original response, it was still capable of distinguishing different glucose concentrations. This work suggests that the SOI–GOx working electrode that we developed might be a promising candidate for implantable glucose sensors.