Aza-BODIPY dye with unexpected bromination and high singlet oxygen quantum yield for photoacoustic imaging-guided synergetic photodynamic/photothermal therapy

Introducing heavy halogen atoms into organic small molecules is a practical strategy for efficient singlet oxygen(^(1)O_(2))generation.Generally,bromine or iodine atoms are introduced on the aza-borondipyrromethene(aza-BODIPY)core,rather than on the periphery aryl rings for efficient~1O_(2) generation.Herein,an aza-BODIPY dye NBDPBr with unexpected bromination on the periphery aryl rings was synthesized for photoacoustic(PA)imaging-guided synergistic photothermal therapy(PTT)and photodynamic therapy(PDT)in tumor cells.Owing to unexcepted bromination at the periphery aryl rings,NBDPBr demonstrated an outstanding singlet oxygen quantum yield(Φ_(Δ))of 66% which was superior to similar brominated photosensitizers previously reported.After encapsulation with amphiphilic polymer F-127,hydrophilic NBDPBr nanoparticles(NPs)were fabricated and exhibited an excellent photothermal conversion efficiency(η)of 43.0% under 660 nm photoirradiation.In vivo PA imaging results demonstrated that NBDPBr NPs could specifically accumulate at tumor sites and realized the maximum tumor retention at 7 h post-injection.All the in vitro and in vivo results indicated the significant potence of NBDPBr with unexpected bis-bromination for PA imaging-guided synergetic PDT/PTT.

Light-responsive organic artificial enzymes:Material designs and bio-applications

As significant biocatalysts,natural enzymes have exhibited a vast range of applications in biocatalytic reactions.However,the“always-on”natural enzyme activity is not beneficial for the regulation of catalytic processes,which limits their bio-applications.Recently,it has been extensively reported that various organic artificial enzymes exhibit prominent absorption and controlled activity under illumination,which not only creates a series of light-responsive catalytic platforms but also plays a key role in biosensing and biomedical research.To provide novel ideas for the design of artificial enzymes,we conduct this review to highlight the recent progress of light-responsive organic artificial enzymes(LOA-Enz).The specific photoresponse mechanism and various bio-applications of LOA-Enz are also presented in detail.Furthermore,the remaining challenges and future perspectives in this field are discussed.