A Photoresponsive Nanozyme For Synergistic Catalytic Therapy And Dual Phototherapy

Phototherapy including photodynamic and photothermal has become a promising cancer treatment method.However,the limited penetration depth of light into tissues and the hypoxic environment severely reduced their therapeutic effects.Recently,with the unique catalytic activity of nanozymes,a new strategy integrating phototherapy and catalytic therapy has been developed,which has effectively promoted the further development of cancer treatment.However,the design of photo-responsive nanozyme systems still needs to be improved.On the one hand,the construction of these therapeutic systems is relatively complex,and the nanocomposites need to integrate multiple functional elements to play a variety of functions.On the other hand,little attention has been paid to the interaction between enzyme-like activities and phototherapy.In this work,we have constructed a simple therapeutic system(FePc/HNCSs)using hollow nitrogen-doped carbon spheres(HNCSs)and phthalocyanine(FePc)with multiple synergistic effects of photoactivity and enzyme-like activities.In vitro study,FePc/HNCSs showed good photothermal stability and high photothermal conversion efficiency of 38.7%.Based on theπ-π interaction between HNCSs and FePc,the enzyme-like activities were significantly enhanced.Under the action of light,the enzyme-like activities of FePc/HNCSs have been significantly improved again,indicating that light is an effective strategy to improve the activities of nanozymes.Due to the CAT-like activity of FePc/HNCSs,the photodynamic performance was effectively improved.FePc/HNCSs showed a strong therapeutic effect in cell experiments,and could still maintain their effect even under hypoxic conditions.Based on the excellent performance of FePc/HNCSs,a mouse tumor model was constructed to evaluate their therapeutic effect in vivo.The final results showed that FePc/HNCSs achieved a tumor inhibition rate as high as 96.3%.In addition,hemolysis,blood routine and tissue staining tests proved that FePc/HNCSs had good safety in vivo.We believe that this work will provide new ideas for the design of photoresponsive nanozymes and promote the further development of tumor therapy.