Utilization of triplet excited states in organic semiconductors

Organic optoelectronics is an emerging research field, which has attracted extensive interests in the last few decades owing to its practical applications, like organic light-emitting diodes (OLEDs), organic memory devices, organic photovoltaic (OPV), sensors, and organic field-effect transistors[1, 2]. Organic semiconductors play a crucial role in this field. Compared to the traditional inorganic semiconductors, organic semiconductors open a fascinating research direction because of some unique advantages, such as flexible design, low cost, and rich optical and electronic properties. In organic optoelectronics, the excited states greatly determine the photoelectronic properties and application areas as shown in Fig. 1. Based on the electron spin in the molecule, the excited states of organic semiconductors include singlet and triplet states. As we know, the radiative transitions of singlet and triplet excited states are always accompanied by fluorescence and phosphorescence emission, respectively.

De Novo Design of Polymeric Carrier to Photothermally Release Singlet Oxygen for Hypoxic Tumor Treatment

Intratumoral hypoxia extremely limits the clinic applications of photodynamic therapy(PDT).Endoperoxides allow thermally releasing singlet oxygen(1O_(2))in a defned quantity and ofer promising opportunities for oxygen-independent PDT treatment of hypoxic tumors.However,previous composite systems by combining endoperoxides with photothermal reagents may result in unpredicted side efects and potential harmful impacts during therapy in vivo.Herein,we de novo design an all-in-one polymer carrier,which can photothermally release 1O_(2).Te strategy has been demonstrated to efectively enhance the production of 1O_(2) and realize the photodamage in vitro,especially in hypoxic environment.Additionally,the polymer carrier accumulates into tumor afer intravenous injection via the enhanced permeation and retention efects and accelerates the oxygen-independent generation of 1O_(2) in tumors.Te oxidative damage results in good inhibitory efect on tumor growth.Realization of the strategy in vivo paves a new way to construct photothermal-triggered oxygen-independent therapeutic platform for clinical applications.

Luminescent gold nanocluster-based sensing platform for accurate H_(2)S detection in vitro and in vivo with improved anti-interference

Gold nanoclusters(Au NCs)are promising luminescent nanomaterials due to their outstanding optical properties.However,their relatively low quantum yields and environment-dependent photoluminescence properties have limited their biological applications.To address these problems,we developed a novel strategy to prepare chitosan oligosaccharide lactate(Chi)-functionalized Au NCs(Au NCs@Chi),which exhibited emission with enhanced quantum yield and elongated emission lifetime as compared to the Au NCs,as well as exhibited environment-independent photoluminescence properties.In addition,utilizing the free amino groups of Chi onto Au NCs@Chi,we designed a FRET-based sensing platform for the detection of hydrogen sulfide(H_(2)S).The Au NCs and the specific H_(2)S-sensitive merocyanine compound were respectively employed as an energy donor and acceptor in the platform.The addition of H_(2)S induced changes in the emission profile and luminescence lifetime of the platform with high sensitivity and selectivity.Utilization of the platform was demonstrated to detect exogenous and endogenous H_(2)S in vitro and in vivo through wavelength-ratiometric and time-resolved luminescence imaging(TLI).Compared to previously reported luminescent molecules,the platform was less affected by experimental conditions and showed minimized autofluorescence interference and improved accuracy of detection.