Compute-and-Release Logic-Gated DNA Cascade Circuit for Accurate Cancer Cell Imaging.

Accurate identification of cancer cells is an essential prerequisite for cancer diagnosis and subsequent effective curative interventions. The logic-gate-assisted cancer imaging system that allows a comparison of expression levels between biomarkers, rather than just reading biomarkers as inputs, returns a more comprehensive logical output, improving its accuracy for cell identification. To fulfill this key criterion, we develop a compute-and-release logic-gated double-amplified DNA cascade circuit. This novel system, CAR-CHA-HCR, consists of a compute-and-release (CAR) logic gate, a double-amplified DNA cascade circuit (termed CHA-HCR), and a MnO2 nanocarrier. CAR-CHA-HCR, a novel adaptive logic system, is designed to logically output the fluorescence signals after computing the expression levels of intracellular miR-21 and miR-892b. Only when miR-21 is present and its expression level is above the threshold CmiR-21 > CmiR-892b, the CAR-CHA-HCR circuit performs a compute-and-release operation on free miR-21, thereby outputting enhanced fluorescence signals to accurately image positive cells. It is capable of comparing the relative concentrations of two biomarkers while sensing them, thus allowing accurate identification of positive cancer cells, even in mixed cell populations. Such an intelligent system provides an avenue for highly accurate cancer imaging and is potentially envisioned to perform more complex tasks in biomedical studies.

Silver Catalyzed Site-Selective C(sp3)-H Bond Amination of Secondary over Primary C(sp3)-H Bonds.

Sulfamates are widespread in numerous pharmacologically active molecules. In this paper, Silver/Bathophenanthroline catalyzed the intramolecular selective amination of primary C(sp3)-H bonds and secondary C(sp3)-H bonds of sulfamate esters, to produce cyclic sulfamates in good yields and with a high site-selectivity. DFT calculations revealed that the interaction between sulfamates and L10 makes the molecule more firmly attached to the catalyst, benefiting the catalysis reaction. The in vitro anticancer activity of the final products was evaluated in MCF-7 breast cancer cells.