Development And Application Of Composite Nano-Biomaterials In Biochemical Analysis

Cancer has become one of the most deadly diseases in the world,and the development of tumor treatment strategies has become a current research hotspot.In this paper,a multifunctional composite nano-drug delivery system was designed for drug delivery in tumor cells,endogenous miRNA detection,and a combination of multiple treatment methods to treat tumors.1.In order to achieve the detection and imaging of intracellular miRNA-21,and at the same time enhance the therapeutic effect of photodynamic therapy（PDT）by increasing the oxygen content in the cell,and further improve the efficacy of loaded drugs.In this paper,bovine serum albumin（BSA）was used to synthesize CeO₂nanoclusters with catalase（CAT）activity,and the designed X-DNA（X-DNA）structure was modified onto the nanoclusters.Then use the electrostatic interaction of BSA to load the therapeutic drug doxorubicin（DOX）and release the drug in the weakly acidic environment within the tumor cells.X-DNA can respond to the target miRNA-21 by replacing the chain modified with the fluorophore Cy5 to restore its fluorescence and realize the detection and imaging of miRNA-21 in the cell.Cy5 has the ability to distinguish between tumor cells and normal cells,and it has a weak PDT ability.By using CeO₂’s CAT enzyme activity,it can increase the intracellularO₂ concentration,and through sequential catalytic processes,it enhanced the PDT therapeutic effect of Cy5,and furthermore the therapeutic drug DOX produces a synergistic effect and improves the therapeutic effect.2.In order to avoid the limitations of monotherapy,achieve the purpose of combining with multiple treatment methods while achieving drug delivery,synergistically enhancing,and improving the therapeutic effect.Therefore,in this article BSA was used to synthesize IrO₂ nanoparticles with high photothermal conversion efficiency（67.3%）and peroxidase（POD）activity,which can be used for photothermal therapy（PTT）and CDT treatment of tumors.Then the DNAzyme structure modified with Cy5 fluorescent group in response to miRNA-21 was attached to the nanoparticle to play a targeting role.After interacting with the target miRNA-21,the DNAzyme structure was broken to restore the fluorescence,and at the same time,the target miRNA-21 was released for the next detection cycle,realizing signal amplification.Then BSA was used to load the drug DOX,combined with IrO₂’s own PTT and CDT treatment capabilities.The combination of multiple treatment methods was realized,and the treatment effect was greatly improved compared with a single treatment method.In the living tumor model,the tumor volume had been successfully reduced,and the tumor inhibition rate was as high as 93.33%,which has excellent tumor treatment performance.