Detection Of Biomarkers In Tumor Cells Based Onporous Carbon Materials And Construction Of Drug Loading System

Porous carbon spheres?PCNs?have aroused great interest in the past decade due to their excellent physicochemical properties and wide applications.However,the current complex synthesis process has limited its application in various aspects,and the simple and controllable synthesis of porous carbon nanospheres is still a great challenge.In this paper,porous carbon nanospheres?PCNs?were synthesized by a simple method.Compared with traditional nanospheres,the PCN synthesis process does not require a template,only constant temperature reaction and high temperature carbonization process.The pores of the PCN with functionalized carboxyl and amino groups can be loaded with DOX into it by connecting siRNA,and after connecting folic acid,it can target cancer cells to achieve a synergistic therapeutic effect.The drug delivery system not only has negligible cytotoxicity,but also can achieve a high DOX loading of 141?g/mg,which can effectively deliver these substances into cells,thereby achieving stronger cancer cell killing capacity.Second,a dual-signal nanoprobe composed of DNAzyme-functionalized PCNs was designed to respond to microRNA-21 and zinc ions(Zn²⁺).In the presence of microRNA-21 and Zn²⁺,the fluorescence intensity of the fluorescent probe fluorescein isothiocyanate?FITC??excitation/emission wavelength is 488/517 nm?and the fluorescence intensity of anthocyanin 5?Cy5??excitation/emission wavelength is633/670 nm?significantly enhanced.The recognition of microRNA-21 and its complementary strands in PCNs led to the separation of Zn²⁺-specific DNAzymes from PCNs,resulting in enhanced green fluorescence.Exogenous Zn²⁺triggered the cleavage of DNAzyme cleavage strands and restored red fluorescence.This nanoprobe is capable of measuring microRNA-21 in the linear range of 2-300 nM in vitro with a detection limit of 0.57 nM and Zn²⁺in the linear range of 2-100 nM with a detection limit of 0.43nM,and It can achieve in-situ synchronous imaging in MCF-7 breast cancer cells.Therefore,this strategy allows us to obtain the expression levels of different biomarkers in living cells,providing a useful tool for diagnosing cancer and understanding its biological processes.Furthermore,a two-color fluorescent nanoprobe based on porous carbon nanospheres and DNA hybrid hydrogel was designed for simultaneous detection of adenosine triphosphate and glutathione and live cell imaging.Due to the non-template synthesis and good biocompatibility,the preparation time of the nano-hydrogel is short,and it has the characteristics of resisting non-specific adsorption.The fluorescence intensity of FITC and Cy5 of fluorescent probes were significantly enhanced in thiol and adenosine triphosphate?ATP?.The ATP recognizes the aptamer in the nanoprobe,which causes the outer hydrogel to peel off,and separates the two DNAs locked by the aptamer,which causes Cy5 and BHQ3 to move away,red fluorescence recovers,and intracellular thiols can pass through The disulfide bond is cut off,so that the inner hydrogel is peeled off,and the FITC contained in PCNs is released,thereby restoring the green fluorescence of FITC.This nanoprobe can obtain ATP in the range of 10 nM-1.5?M in vitro,with a detection limit of 5.73 nM,and thiol in the range of 50 nM-1.0?M,with a detection limit of 18.2 nM,and in Simultaneous in situ imaging in MCF-7 breast cancer cells.Therefore,this strategy can simultaneously detect different biomarkers in tumor cells to achieve early detection and discovery.