A colorimetric-based amplification system for proteinases including MMP2 and ADAM8

Biosensors Based on the Binding Events of Nitrilotriacetic Acid-Metal Complexes

Molecular immobilization and recognition are two key events for the development of biosensors. The general ways for the immobilization and recognition of biomolecules include covalent coupling reactions and non-covalent interactions of antigen-antibody, aptamer-target, glycan-lectin, avidin-biotin and boronic acid-diol. Tetradentate nitrilotriacetic acid (NTA) is one of the most common commercial ligands for chelating metal ions. The NTA-metal complexes show high and specific affinity toward hexahistidine tags. Such metal complexes have been widely utilized in protein separation and immobilization for diagnostic applications since most of commercialized proteins have been integrated with hexahistidine tags by synthetic or recombinant techniques. This review focused on the development of biosensors with NTA-metal complexes as the binding units, mainly including surface plasmon resonance, electrochemistry, fluorescence, colorimetry, surface-enhanced Raman scattering spectroscopy, chemiluminescence and so on.

Clinical Evaluation of Pathognomonic Salivary Protease Fingerprinting for Oral Disease Diagnosis

Dental decay (Caries) and periodontal disease are globally prevalent diseases with significant clinical need for improved diagnosis. As mediators of dental disease-specific extracellular matrix degradation, proteases are promising analytes. We hypothesized that dysregulation of active proteases can be functionally linked to oral disease status and may be used for diagnosis. To address this, we examined a total of 52 patients with varying oral disease states, including healthy controls. Whole mouth saliva samples and caries biopsies were collected and subjected to analysis. Overall proteolytic and substrate specific activities were assessed using five multiplexed, fluorogenic peptides. Peptide cleavage was further described by inhibitors targeting matrix metalloproteases (MMPs) and cysteine, serine, calpain proteases (CSC). Proteolytic fingerprints, supported by supervised machine-learning analysis, were delineated by total proteolytic activity (PepE) and substrate preference combined with inhibition profiles. Caries and peridontitis showed increased enzymatic activities of MMPs with common (PepA) and divergent substrate cleavage patterns (PepE), suggesting different MMP contribution in particular disease states. Overall, sensitivity and specificity values of 84.6% and 90.0%, respectively, were attained. Thus, a combined analysis of protease derived individual and arrayed substrate cleavage rates in conjunction with inhibitor profiles may represent a sensitive and specific tool for oral disease detection.

Tricolor imaging of MMPs to investigate the promoting roles of inflammation on invasion and migration of tumor cells

The expression levels of matrix metalloproteinases (MMPs) are closely related to the degree of inflammation which facilitates tumor cells' invasion and migration. A tricolor fluorescence nanoprobe based on high-fidelity gold-selenium (Au-Se) nanoplatform was designed and constructed for simultaneously imaging matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-7 (MMP-7) and matrix metalloproteinase-9 (MMP-9) to thoroughly investigate the tumor cells' invasion and migration behaviors under inflammation environment. The nanoprobe was assembled by attaching Au NPs with three different peptide substrates respectively labeled with fluorescein isothiocyanate (FITC), 5-carboxytetramethylrhodamine (5-TAMRA) and cyanine 5 (Cy5) via the Au-Se bond. The nanoprobe can specifically respond to MMP-2/7/9, thereby triggering the fluorophores' fluorescence that quenched previously by fluorescence resonance energy transfer (FRET) to realize the MMP-2/7/9's visualization in biological systems. Moreover, as the inflammation stimulated by different concentrations lipopolysaccharide (LPS), the expression of MMP-2/7/9 in SMMC-7721 cells was observed to be significantly enhanced by confocal laser scanning microscope (CLSM) imaging, and inflammation was further proved to intensify SMMC-7721 cells' invasion and migration by transwell invasion and migration experiments. Therefore, the nanoprobe can be used to monitor biomarkers to provide a visual system for the degree of invasion and migration of tumor cells in an inflammatory environment, and also offer a new strategy for the study of the correlation between various active biomacromolecules and specific intracellular pathways in cells.