SARS-CoV-2 diagnostic practices broadly involve either quantitative polymerase chain reaction (qPCR)-based nucleic amplification of viral sequences or antigen-based tests such as lateral flow assays (LFAs). Reverse transcriptase-qPCR can detect viral RNA and is the gold standard for sensitivity. However, the technique is time-consuming and requires expensive laboratory infrastructure and trained staff. LFAs are lower in cost and near real time, and because they are antigen-based, they have the potential to provide a more accurate indication of a disease state. However, LFAs are reported to have low real-world sensitivity and in most cases are only qualitative. Here, an antigen-based electrochemical aptamer sensor is presented, which has the potential to address some of these shortfalls. An aptamer, raised to the SARS-CoV-2 spike protein, was immobilized on a low-cost gold-coated polyester substrate adapted from the blood glucose testing industry. Clinically relevant detection levels for SARS-CoV-2 are achieved in a simple, label-free measurement format using sample incubation times as short as 15 min on nasopharyngeal swab samples. This assay can readily be optimized for mass manufacture and is compatible with a low-cost meter.
Antibiotic resistance has been cited by the World Health Organisation (WHO) as one of the greatest threats to public health. Mitigating the spread of antibiotic resistance requires a multipronged approach with possible interventions including faster diagnostic testing and enhanced antibiotic stewardship. This study employs a low-cost diagnostic sensor test to rapidly pinpoint the correct antibiotic for treatment of infection. The sensor comprises a screen-printed gold electrode, modified with an antibiotic-seeded hydrogel to monitor bacterial growth. Electrochemical growth profiles of the common microorganism, Escherichia coli (E. coli) (ATCC 25922) were measured in the presence and absence of the antibiotic streptomycin. Results show a clear distinction between the E. coli growth profiles depending on whether streptomycin is present, in a timeframe of ≈2.5 h (p < 0.05), significantly quicker than the current gold standard of culture-based antimicrobial susceptibility testing. These results demonstrate a clear pathway to a low cost, phenotypic and reproducible antibiotic susceptibility testing technology for the rapid detection of E. coli within clinically relevant concentration ranges for conditions such as urinary tract infections.
Stimuli‐responsive molecularly imprinted polymers (MIPs) are exciting smart materials that are gaining substantial interest within the research community due to their versatility and possible widespread applications in biosensing, biomedicine and diagnostics, as well as chromatography and separation sciences. These materials offer significant advantages as recognition materials over their biological counterparts (antibodies) because of their ease and low cost of production along with their robustness and resistance to the extremes of temperature and pH. This much needed review aims to provide an updated summary of the various stimuli‐responsive MIPs reported to date including those relying on thermo, pH, photo, biomolecule, ion, magnetic and electrical stimuli and includes their design and synthesis. The review also explores the potential applications of the stimuli‐responsive MIPs, particularly in the fields of biosensors and diagnostics, along with biological imaging, drug delivery, disease treatments and interventions and the separation of targets from complex media. The advantages and disadvantages of the current stimuli‐responsive MIPs set out in the review, allows for researchers to gather a concise understanding of these smart‐materials and should pave the way for new methods of development and real‐world applications. We believe the review is a helpful and necessary guide for the future evolution and application of stimuli‐responsive MIPs.