Molecular beacons that could convert specific chemical reactions or binding events into measurable signals are essential tools to help understand cellular and subcellular activities at the molecular level. Current in vivo use of molecular beacons is limited by their poor stability and easy degradation due to exposure of the linker between the reporter and the quencher to the physiological environment. In this context, we show a proof-of concept design and synthesis of a new type of supramolecular nano-beacon that is resistant to non-specific enzymatic degradation in the self-assembled state but can be effectively cleaved by the target enzyme in the monomeric form. Our results showed that the nano-beacon molecule with a cleavable peptide linker self-assembles into spherical nanostructures of approximately 11 nm under physiological conditions. Enzyme digestion experiments showed that these nano-beacons could serve as an indicator for both the presence and quantity of cathepsin-B, a lysosomal enzyme that is over-expressed in many cancerous cell lines. In vitro study further supports our concept as 5-FAM fluorescence was observed after incubated in MCF-7 cells for 30 minutes and fluorescence intensity was quantified by flow-cytometry.

Design and construction of supramolecular nanobeacons for tumor site detection and imaging

244th National Meeting (2012)

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