Picomolar-sensitive impedimetric sensor for salivary calcium analysis at POC based on SAM of Schiff base–modified gold electrode

Considerable advances in point-of-care testing (POCT) devices stem from innovations in cellphone (CP)-based technologies, paper-based assays (PBAs), lab-on-a-chip (LOC) platforms, novel assay formats, and strategies for long-term reagent storage. Various commercial CP platforms have emerged to provide cost-effective mobile health care and personalized medicine. Such assay formats, as well as low-cost PBAs and LOC-based assays, are paving the way to robust, automated, simplified, and cost-effective POCT. Strategies have also been devised to stabilize reagent storage and usage at ambient temperature. Nevertheless, successful commercialization and widespread implementation of such clinically viable technologies remain subject to several challenges and pending issues.

It is the nature of the calcium signal, as determined by the coordinated activity of a suite of calcium channels, pumps, exchangers and binding proteins that ultimately guides a cell's fate. Deregulation of the calcium signal is often deleterious and has been linked to each of the 'cancer hallmarks'. Despite this, we do not yet have a full understanding of the remodeling of the calcium signal associated with cancer. Such an understanding could aid in guiding the development of therapies specifically targeting altered calcium signaling in cancer cells during tumorigenic progression. Findings from some of the studies that have assessed the remodeling of the calcium signal associated with tumorigenesis and/or processes important in invasion and metastasis are presented in this review. The potential of new methodologies is also discussed. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.

Early disease detection is not only vital to reduce disease severity and prevent complications, but also critical to increase success rate of therapy. Saliva has been studied extensively as a potential diagnostic tool over the last decade due to its ease and non-invasive accessibility along with its abundance of biomarkers, such as genetic material and proteins. This review will update the clinician on recent advances in salivary biomarkers to diagnose autoimmune diseases (Sjogren's syndrome, cystic fibrosis), cardiovascular diseases, diabetes, HIV, oral cancer, caries and periodontal diseases. Considering their accuracy, efficacy, ease of use and cost effectiveness, salivary diagnostic tests will be available in dental offices. It is expected that the advent of sensitive and specific salivary diagnostic tools and the establishment of defined guidelines and results following rigorous testing will allow salivary diagnostics to be used as chair-side tests for several oral and systemic diseases in the near future.