The widespread use of silver nanoparticles (AgNPs) is accompanied by a growing concern regarding their potential risks to human health, thus calling for an increased understanding of their biological effects. The aim of this work was to systematically study the extent to which changes in cellular metabolism were dependent on the properties of AgNPs, using NMR metabolomics. Human skin keratinocytes (HaCaT cells) were exposed to citrate-coated AgNPs of 10, 30 or 60 nm diameter and to 30 nm AgNPs coated either with citrate (CIT), polyethylene glycol (PEG) or bovine serum albumin (BSA), to assess the influence of NP size and surface chemistry. Overall, CIT-coated 60 nm and PEG-coated 30 nm AgNPs had the least impact on cell viability and metabolism. The role of ionic silver and reactive oxygen species (ROS)-mediated effects was also studied, in comparison to CIT-coated 30 nm particles. At concentrations causing an equivalent decrease in cell viability, Ag(+ )ions produced a change in the metabolic profile that was remarkably similar to that seen for AgNPs, the main difference being the lesser impact on the Krebs cycle and energy metabolism. Finally, this study newly reported that while down-regulated glycolysis and disruption of energy production were common to AgNPs and H2O2, the impact on some metabolic pathways (GSH synthesis, glutaminolysis and the Krebs cycle) was independent of ROS-mediated mechanisms. In conclusion, this study shows the ability of NMR metabolomics to define subtle biochemical changes induced by AgNPs and demonstrates the potential of this approach for rapid, untargeted screening of pre-clinical toxicity of nanomaterials in general.

Magnetic nanoparticles effective in the selective recovery of metalloproteases from human saliva were fabricated by surface modification of Fe3O4@SiO2 nanoparticles with EDTA-TMS.

The comparison between the salivary peptidome obtained by control and CP samples showed a specific association of eight peptides to CP, with remarkable predicted antimicrobial activity, which should be further validated in studies with large number of subjects.

The development of portable low-cost integrated optics-based biosensors for photonics-on-a-chip devices for real-time diagnosis are of great interest, offering significant advantages over current analytical methods. We report the fabrication and characterization of an optical sensor based on a Mach-Zehnder interferometer to monitor the growing concentration of bacteria in a liquid medium. The device pattern was imprinted on transparent self-patternable organic-inorganic di-ureasil hybrid films by direct UV-laser, reducing the complexity and cost production compared with lithographic techniques or three-dimensional (3D) patterning using femtosecond lasers. The sensor performance was evaluated using, as an illustrative example, E. coli cell growth in an aqueous medium. The measured sensitivity (2 × 10−4 RIU) and limit of detection (LOD = 2 × 10−4) are among the best values known for low-refractive index contrast sensors. Furthermore, the di-ureasil hybrid used to produce this biosensor has additional advantages, such as mechanical flexibility, thermal stability, and low insertion losses due to fiber-device refractive index mismatch (~1.49). Therefore, the proposed sensor constitutes a direct, compact, fast, and cost-effective solution for monitoring the concentration of lived-cells.

Proteases play a pivotal role in several biological processes, from digestion, cell proliferation, and differentiation to fertility. Deregulation of protease metabolism can result in several pathological conditions (i.e., cancer, neurodegenerative disorders, and others). Therefore, monitoring proteolytic activity in real time could have a fundamental role in the early diagnosis of these diseases. Herein, the main approaches used to develop biosensors for monitoring proteolytic activity are reviewed. A comparison of the advantages and disadvantages of each approach is provided along with a discussion of their importance and promising opportunities for the early diagnosis of severe diseases. This new era of biosensors can be characterized by the ability to control and monitor biological processes, ultimately improving the potential of personalized medicine. Biosensing in Personalized Medicine: The Emergence of Protease BiomarkersA deep understanding of the individual characteristics of biological processes and precise control of responses and feedback to therapies are essential in a world that is running towards personalized medicine (see Glossary). Recent reports predict that this market will grow at a compound annual growth rate (CAGR) of over 11% from US$92.4 billion dollars in 2017 to US$194.4 billion in 2024 (https://www.researchandmarkets.com/research/n5kqz7/global?w=5), with oncology responsible for 30% of the revenues generated. Biosensors are one of the underlying technologies of personalized medicine, giving support to the highly informed decisions that are critical to obtain better clinical outcomes and to decrease undesired side-effects. Compared with the personalized medicine market, a similar tendency is observed for the biosensors market where growth from US$18.6 billion dollars in 2018 to US$31.5 billion in 2025 (8% CAGR) is expected (https://www.gminsights.com/industry-analysis/biosensors-market).One of the primary goals of a biosensor is to determine the presence/absence or activity of a given biomarker and to correlate these results with pathophysiological conditions. Proteases are emerging as a new category among the wide variety of biomarkers targeted by biosensors due to their key role in health and disease. In this review, we present the main approaches used to measure proteolytic activity in real timefor both in vivo and in vitro applicationsand discuss recent developments in and future possibilities for protease biosensors (Figure 1A). The Roles and Idiosyncrasies of Proteases: Why Monitor Proteolytic Activity?Proteases are a widely explored research topic as illustrated by more than 487 000 entries registered in PUBMED. However, it was only recently that proteases emerged as an analyte of interest for biosensing [68]. These hydrolytic enzymes (EC 3.4) play a pivotal role in several biological processes, such as digestion, cell proliferation, and differentiation [1], as well as apoptosis [2], coagulation [3], immunity [4], and fertility [5]. The deregulation of protease metabolism can resul...