Research On The Construction And Performance Of An Integrated Nano-drug Delivery System For The Diagnosis And Treatment Of Colorectal Cancer

Colorectal cancer（CRC）is one of the most common malignant tumors.In the global statistics in 2022,its morbidity and mortality ranks third in both men and women,and the number of patients is increasing year by year,posing a huge threat to human health.Therefore,how to specifically diagnose and effectively treat CRC is an urgent and important clinical issue.In recent years,researchers have developed a series of stimulus-responsive drug delivery systems based on the conventional characteristics of microacidity,hypoxia,high expression of reactive oxygen species and glutathione in the tumor site,and targeted the special endogenous microenvironment of the CRC site.（Hydrogen sulfide,spermine,azo reductase,etc.）target design is rarely involved.Based on this,this article constructs several CRC endogenous stimulus-responsive drug delivery systems for integrated research on diagnosis and treatment of CRC.The details are as follows:In the first part,a nano-hybrid Cu₂O/BNN6@MSN-Dex system was constructed by using mesoporous silica（MSN）as a carrier,supporting Cu₂O and a nitric oxide（NO）donor BNN6.The nanomaterial reacts in situ with endogenous hydrogen sulfide（H₂S）,which is highly expressed in colon cancer,to generate Cu₉S₈with photoacoustic imaging function and photothermal effect.In vitro and in vivo photoacoustic and photothermal experiments have confirmed that this H₂S in situ response activated colon cancer diagnosis and treatment method has excellent photoacoustic imaging and PTT/NO synergistic therapeutic effects.In the second part,with Cu₂O as the core and dopamine（PDA）as the shell,a shell-core structure Cu₂O@PDA-FA system was constructed.In vitro experiments confirmed that Cu₂O@PDA-FA has excellent photoacoustic imaging functions and photothermal effects,and can repolarize cancer-promoting M2 macrophages to tumor suppressor M1,which is expected to be used for anti-CRC under the guidance of photoacoustic imaging Photothermal/immune"multimodal"therapy.