Adenosine triphosphate-responsive carbon dots nanoreactors for T_(1)-weighted magnetic resonance imaging-guided tumor chemodynamic therapy

There are various strategies to conduct tumor microenvironment(TME)stimulus-responsive(e.g.,acid,H_(2)O_(2)or glutathione)nanoreactors for increasing the efficiency of chemodynamic therapy(CDT).Among these,the exploitation of adenosine triphosphate(ATP,another overexpressed biomarker in TME)-responsive nanoreactors for tumor CDT is still challenging.Herein,the ATP-responsive iron-doped CDs(FeCDs)were firstly prepared and then coassembled with glucose oxidase(GOx)to obtain FeCDs/GOx liposomes as ATP-responsive nanoreactors.Under TME conditions,the nanoreactors initially released FeCDs and GOx.Subsequently,with the existence of ATP,iron ions were rapidly released from the FeCDs to trigger Fenton/Fenton-like reactions for generating·OH.Meanwhile,the T_(1)-weighted magnetic resonance imaging(MRI)was achieved due to the released iron ions.Moreover,the GOx converted endogenous glucose in tumor to gluconic acid and H_(2)O_(2)to satisfy the requirement of·OH generation.In vitro as well as in vivo experiments illustrated that the obtained ATP-responsive CD nanoreactors could be used as a versatile nanotheranostics for simultaneously T_(1)-weighted MRI-guided tumor CDT.This work presents a new ATP-responsive nanoreactor with selfsupplied H_(2)O_(2)for multifunctional nanotheranostic applications.

Polythiophene Derivatives Carbonized Polymer Dots:Aggregation Induced Solid-State Fluorescence Emission

Comprehensive Summary Currently,solid-state fluorescent carbonized polymer dots(CPDs)have attracted attention increasingly due to their applications for optoelectronic display.However,designing CPDs possessing solid-state fluorescence and clarifying the fluorescence mechanism remain challenging.Herein,we initially synthesized a novel type of polythiophene derivatives CPDs,poly-4,4’-(thiophene-3,4-diyl)dibenzoic acid carbonized polymer dots(PDBA-CPDs)with solid-state fluorescence.Subsequently,the structural and optical characterization revealed that the solid-state fluorescence originated from the aggregation induced emission of the CPDs.In brief,in aggregation state,the remaining polymer structure groups on the surface of the CPDs overlapped and weakened the non-radiative transition,enhancing solid-state fluorescence emission.Thirdly,three polythiophene-derived CPDs were designed to further demonstrate the aggregation induced solid-state fluorescence mechanism.Finally,owing to their unique properties of solid-state fluorescence,the white LEDs(light emitting diodes)were fabricated with high color rendering index(CRI)of 82.7 and CIE coordinates of(0.37,0.39)using commercial 460 nm chip.

PEGylated carbon dot/MnO_2 nanohybrid: a new pH/H_2O_2-driven, turn-on cancer nanotheranostics

The effect of tumor-targeted photodynamic therapy（PDT） was improved by designing nanotheranostics to promote oxygenation in a tumor microenvironment（TME）wherein hypoxia, acidosis, and the elevated levels of H2O2 are three main characteristics. In this study, a carbon dot（CD）PDT agent recently developed by our group was firstly applied as reducing agent to react with potassium permanganate for fabricating CDs/manganese dioxide（CDs/MnO2） composites,which were in turn modified with polyethylene glycol（PEG） to form water-soluble CDs/MnO2-PEG nanohybrids. In a normal physiological environment, the as-prepared nanohybrids exhibited quenched fluorescence, weak singlet oxygen generation, and low magnetic resonance imaging（MRI） signal.However, given the high sensitivity of MnO2 to the TME, the CDs/MnO2-PEG nanohybrids changed from an ＂off＂ to an＂on＂ state with synchronously enhanced fluorescence, singlet oxygen generation, and MRI signal in the TME. In vitro and in vivo analyses have revealed that CDs/MnO2-PEG nanohybrids could be applied as TME-driven, turn-on nanotheranostics for the MR/fluorescence bimodal imaging-guided PDT of cancer.Moreover, complete clearance of CDs/MnO2-PEG nanohybrids from the body of mice was observed, indicating their low long-term toxicity and good biocompatibility. This work offers a new nanotheranostic candidate for modulating the unfavorable TME, particularly for the targeted PDT of cancer through precise positioning and oxygen generation.