A disclosure gel for visual detection of live Bacillus anthracis spores

AIMS: To develop a gel formulation to trigger a visual signal for rapid disclosure of the location and extent of surface contamination with viable Bacillus anthracis spores. METHODS AND RESULTS: Methylumbelliferyl‐α‐d‐glucopyranoside was combined with hyaluronic acid to produce a gel that could be applied to a surface as a coating. It remained hydrated for a sufficient time for α‐glucosidase activity present in intact B. anthracis spores to cleave the substrate and release the fluorescent product, methylumbelliferone. The presence of B. anthracis spores could be disclosed at 5 × 10(4) CFU per reaction test well (0·32 cm(2)) both visually and using fluorescence detection equipment. CONCLUSIONS: The disclosure gel provides a rapid, visual response to the presence of B. anthracis spores on a surface. SIGNIFICANCE AND IMPACT OF THE STUDY: The disclosure gel demonstrates the first steps towards the development of a formulation that can provide nonspecialist users with a visual alert to the presence of B. anthracis spores on a surface. It is envisioned that such a formulation would be beneficial in scenarios where exposure to spore release is a risk, and could be used in the initial assessment of equipment to aid prioritization and localized execution of a decontamination strategy.