DNA nanostrucures are promising materials for biomedical applications. Herein, we established a "sense-and-treat" localized drug delivery system based on a DNA nanodevice to specifically destroy circulating tumor cells (CTCs) by synergetic chemotherapy and photodynamic therapy. The DNA nanodevices could sense the existence of CTCs and treat CTCs with anticancer agents. Typically, the presence of target cell promoted the formation of hairpin structure of aptamer, and then the aptamer-accompanied DNA tetrahedron would release from the supporter. The chemotherapy drugs (doxorubicin, Dox) loaded in DNA tetrahedron would destroy the CTCs specifically. Moreover, the photosensitizer labeled on DNA tetrahedron would be activated by lights and generated toxic O, once DNA nanodevices bound CTCs flow through the superficial capillary. Unlike the aptamer only labeled with photosensitizer, the DNA nanodevice showed the capability to promote cellular internalization of anticancer agents, increase drug loading capacity, and realize synergetic therapy, which enhanced the destructive ability of anticancer agents. As proof of concept, this DNA nanodevice has the potential to inhibit metastasis by synergetic destruction of CTCs.
Pancreatic polypeptide (PP) is a specific biomarker of nonfunctional pancreatic neuroendocrine tumors (NF-pNETs). Clinical significance of PP inspires researchers to make great efforts in developing sensitive and specific sensors. However, there is no existing biosensor for detecting PP that combines facility and functionality. Addressing this challenge, a pair of aptamers which could be used to develop a sandwich assay for PP is reported. First, several high affinity aptamers are screened through graphene oxide-based SELEX, and appropriate dual-aptamers which could bind to different epitopes of PP are identified through fluorescence assays. Then the feasibility of the dual-aptamers for constructing the sandwich assay is validated via dynamic light scattering. This sandwich assay shows considerable sensitivity and specificity. The above results imply that the dual-aptamers have the potential toward developing novel sensors for PP in clinical samples.
Existing drug delivery systems were not suitable for killing cells in the circulatory system specifically. Herein, we developed a novel localized drug delivery strategy, in which the release of anticancer agents was specifically triggered by circulating tumor cells. Meanwhile, damage to non-target cells was avoided.
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