Electrical monitoring of infection biomarkers in chronic wounds using nanochannels

Chronic wounds represent an important healthcare challenge in developed countries, being wound infection a serious complication with significant impact on patients’ life conditions. However, there is a lack of methods allowing an early diagnosis of infection and a right decision making for a correct treatment. In this context, we propose a novel methodology for the electrical monitoring of infection biomarkers in chronic wound exudates, using nanoporous alumina membranes. Lysozyme, an enzyme produced by the human immune system indicating wound infection, is selected as a model compound to prove the concept. Peptidoglycan, a component of the bacterial layer and the native substrate of lysozyme, is immobilized on the inner walls of the nanochannels, blocking them both sterically and electrostatically. The steric blocking is dependent on the pore size (20 - 100 nm) and the peptidoglycan concentration, whereas the electrostatic blocking depends on the pH. The proposed analytical method is based on the electrical monitoring of the steric/electrostatic nanochannels unblocking upon the specific degradation of peptidoglycan by lysozyme, allowing to detect the infection biomarker at 280 ng/mL levels, which are below those expected in wounds. The low protein adsorption rate and thus outstanding filtering properties of the nanoporous alumina membranes allowed us to discriminate wound exudates from patients with both sterile and infected ulcers without any sample pre-treatment usually indispensable in most diagnostic devices for analysis of physiological fluids. Although size and charge effects in nanochannels have been previously approached for biosensing purposes, as far as we know, the use of nanoporous membranes for monitoring enzymatic cleavage processes, leading to analytical systems for the specific detection of the enzymes has not been deeply explored so far. Compared with previously reported methods, our methodology presents the advantages of no need of neither bioreceptors (antibodies or aptamers) nor competitive assays, low matrix effects and quantitative and rapid analysis at the point-of-care, being also of potential application for the determination of other protease biomarkers.Peer ReviewedPostprint (published version

Bifunctional Au@Pt/Au nanoparticles as electrochemiluminescence signaling probes for SARS-CoV-2 detection

A novel immunosensor based on electrochemiluminescence resonance energy transfer (ECL-RET) for the sensitive determination of N protein of the SARS-CoV-2 coronavirus is described. For this purpose, bifunctional core@shell nanoparticles composed of a Pt-coated Au core and finally decorated with small Au inlays (Au@Pt/Au NPs) have been synthesized to act as ECL acceptor, using [Ru (bpy)3]2+ as ECL donor. These nanoparticles are efficient signaling probes in the immunosensor developed. The proposed ECL-RET immunosensor has a wide linear response to the concentration of N protein of the SARS-CoV-2 coronavirus with a detection limit of 1.27 pg/mL. Moreover, it has a high stability and shows no response to other proteins related to different virus. The immunosensor has achieved the quantification of N protein of the SARS-CoV-2 coronavirus in saliva samples. Results are consistent with those provided by a commercial colorimetric ELISA kit. Therefore, the developed immunosensor provides a feasible and reliable tool for early and effective detection of the virus to protect the populationThe authors wish to express their sincere thanks to the Spanish Ministerio de Ciencia e Innovacion (MICINN) (PID2020-116728RB-I00 and PID2020-115204RB-I00) and the Comunidad Autonoma ´ de Madrid (S2018/NMT-4349 TRANSNANOAVANSENS-CM Program, SI3/PJI/ 2021–00341 and 2021-5A/BIO-20943 Talent Attraction Project) for the financial support. C. Toyos-Rodríguez acknowledges the MICINN for the award of a FPI Grant (PRE2018-084953). A. de la Escosura-Muniz ˜ also thanks the MICINN for the research founding by a “Ramon ´ y Cajal” contract (RyC-2016-20299

Next‐generation sequencing reveals that miR‐16‐5p, miR‐19a‐3p, miR‐451a, and miR‐25‐3p cargo in plasma extracellular vesicles differentiates sedentary young males from athletes

A sedentary lifestyle and Olympic participation are contrary risk factors for global mortality and incidence of cancer and cardiovascular disease. Extracellular vesicle miRNAs have been described to respond to exercise. No molecular characterization of young male sedentary people versus athletes is available; so, our aim was to identify the extracellular vesicle miRNA profile of chronically trained young endurance and resistance male athletes compared to their sedentary counterparts. A descriptive case–control design was used with 16 sedentary young men, 16 Olympic male endurance athletes, and 16 Olympic male resistance athletes. Next‐generation sequencing and RT‐qPCR and external and internal validation were performed in order to analyze extracellular vesicle miRNA profiles. Endurance and resistance athletes had significant lower levels of miR‐16‐5p, miR‐19a‐3p, and miR‐451a compared to sedentary people. Taking all together, exercise‐trained miRNA profile in extracellular vesicles provides a differential signature of athletes irrespective of the type of exercise compared to sedentary people. Besides, miR‐25‐3p levels were specifically lower in endurance athletes which defines its role as a specific responder in this type of athletes. In silico analysis of this profile suggests a role in adaptive energy metabolism in this context that needs to be experimentally validated. Therefore, this study provides for the first time basal levels of circulating miRNA in extracellular vesicles emerge as relevant players in intertissue communication in response to chronic exercise exposure in young elite male athletes

Nanopartículas magnéticas en biomedicina

El interés por las nanoparticulas superparamagnéticas ha ido creciendo en los últimos años debido a sus múltiples aplicaciones biomédicas, entre ellas su potencial como transportadores de fármacos. Su carácter superparamagnético permite que, bajo la presencia de un campo magnético externo, las partículas puedan ser llevadas a un órgano diana y/o quedar retenidas en él durante un tiempo suficientemente largo como para permitir la liberación del fármaco. Esta cualidad es de especial importancia para tratamientos donde la solubilidad del medicamento sea un problema. Este es el caso de la melatonina (N-acetyl-5-methoxytryptamine), hormona que ha demostrado ser eficaz en el tratamiento de tumores como el glioblastoma, principal tumor cerebral en humanos. En este trabajo se ha llevado a cabo el desarrollo de unas partículas superparamagnéticas compuestas de magnetita y recubiertas con quitasol entrecruzado con glutaraldehido, capaces de retener melatonina