In this technical note the often overlooked issue of electrically connecting screen-printed electrode sensors is considered. The electrical connection of screen-printed electrodes to the potentiostat/ electronics can be a main issue when a true electrochemical response is trying to be obtained and if one does not have a stable electrical connection, the results that are obtained may lack reproducibility and therefore maybe discredited as "another failed electrochemical probe/analyte". This paper considers the case of electrically connecting screen-printed with crocodile clips and compares that to the use of edge-connectors demonstrating the precise connection of an electrode setup when utilising crocodile clips can result in extremely reproducible electrochemical outputs when applied correctly.
Antibiotic resistant pathogens are a modern threat to the human health. As a worldwide spreading problem, there is an urgency for new strategies to minimize antibiotic resistance, particularly the super‐resistant strains. Here, the efficient design of carbohydrate‐coated silica nanoparticles is reported which specifically target Gram‐negative bacteria cells. The system is functionalized with gluconamide moieties and demonstrates increased binding ability to the bacterial membrane, enabling controlled drug delivery onto the pathogen wall. In addition, the high stability of the nanoparticles in biological media and the lack of non‐specific protein adhesion are engendered by such functionalization, which also demonstrates low cytotoxicity and hemolytic activity prevention. Local interaction between nanoparticles and the bacterium membrane is experimentally accessed at the biomolecular level unveiling a short‐range chemical connection. Atomistic molecular dynamics simulations depict the rapid penetration of gluconamide in the lipopolysaccharide region of the bacterial outer membrane, corroborating the experimental findings. Thus, this novel outer membrane‐targeting platform provides a new strategy to reduce drug intake and, hence, minimize bacterial resistance.
A reagentless pH sensor based upon disposable and economical graphite screen-printed electrodes (GSPEs) is demonstrated for the first time. The voltammetric pH sensor utilizes GSPEs which are chemically pretreated to form surface immobilized oxygenated species that, when their redox behavior is monitored, give a Nernstian response over a large pH range (1-13). An excellent experimental correlation is observed between the voltammetric potential and pH over the entire pH range of 1-13 providing a simple approach with which to monitor solution pH. Such a linear response over this dynamic pH range is not usually expected but rather deviation from linearity is encountered at alkaline pH values; absence of this has previously been attributed to a change in the pKa value of surface immobilized groups from that of solution phase species. This non-deviation, which is observed here in the case of our facile produced reagentless pH sensor and also reported in the literature for pH sensitive compounds immobilized upon carbon electrodes/surfaces, where a linear response is observed over the entire pH range, is explained alternatively for the first time. The performance of the GSPE pH sensor is also directly compared with a glass pH probe and applied to the measurement of pH in "real" unbuffered samples where an excellent correlation between the two protocols is observed validating the proposed GSPE pH sensor.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.