Dongliang Yang

Microwave-assisted solvothermal preparation of nitrogen and sulfur co-doped reduced graphene oxide and graphene quantum dots hybrids for highly efficient oxygen reduction

A facile solvothermal method assisted by microwave irradiation was developed for preparing nitrogen and sulfur co-doped reduced graphene oxide functionalized with fluorescent graphene quantum dots (N,S-RGO/GQDs). Graphene quantum dots (GQDs) show high fluorescence and excitation-dependent fluorescent properties. The resultant N,S-RGO/GQDs hybrids as a kind of metal-free electrocatalyst were demonstrated to have good catalytic properties with long-term operational stability and tolerance to the crossover effects of methanol for oxygen reduction via a four-electron pathway in alkaline solution. This research not only develops a low-cost, economic and scalable approach for preparing a metal-free electrocatalyst for the oxygen reduction reaction (ORR), but also produces nitrogen and sulfur co-doped graphene quantum dots (N,S-GQDs) with high fluorescent characteristics.

Early Lung Cancer Diagnosis by Biosensors

Lung cancer causes an extreme threat to human health, and the mortality rate due to lung cancer has not decreased during the last decade. Prognosis or early diagnosis could help reduce the mortality rate. If microRNA and tumor-associated antigens (TAAs), as well as the corresponding autoantibodies, can be detected prior to clinical diagnosis, such high sensitivity of biosensors makes the early diagnosis and prognosis of cancer realizable. This review provides an overview of tumor-associated biomarker identifying methods and the biosensor technology available today. Laboratorial researches utilizing biosensors for early lung cancer diagnosis will be highlighted.

Preparation of Highly Dispersed Reduced Graphene Oxide Decorated with Chitosan Oligosaccharide as Electrode Material for Enhancing the Direct Electron Transfer of Escherichia coli

Water-dispersed reduced graphene oxide/chitosan oligosaccharide (RGO-CTSO) was prepared by chemical reduction of graphene oxide and synchronous functionalization with biocompatible chitosan oligosaccharide (CTSO). ζ potential measurement indicated that RGO-CTSO was highly stable in the acidic aqueous solution. RGO-CTSO was used to modify glassy carbon electrode (GCE) as the growth template of Escherichia coli (E. coli). The enhanced direct electron transfer of E. coli on the RGO-CTSO-modified GCE was studied by cyclic voltammetry. Compared with GCE or RGO-modified GCE, RGO-CTSO-modified GCE was more suitable for the adhesion growth of E. coli to improve direct electron transfer. The biocompatibility and versatility of RGO-CTSO made it promising for use as an anode material in microbial fuel cells.

Thermally Activated Delayed Fluorescence Organic Dots (TADF Odots) for Time‐Resolved and Confocal Fluorescence Imaging in Living Cells and In Vivo

The fluorophores with long‐lived fluorescent emission are highly desirable for time‐resolved fluorescence imaging (TRFI) in monitoring target fluorescence. By embedding the aggregates of a thermally activated delayed fluorescence (TADF) dye, 2,3,5,6‐tetracarbazole‐4‐cyano‐pyridine (CPy), in distearoyl‐sn‐glycero‐3‐phosphoethanolamine‐poly(ethylene glycol) (DSPE‐PEG2000) matrix, CPy‐based organic dots (CPy‐Odots) with a long fluorescence lifetime of 9.3 μs (in water at ambient condition) and high brightness (with an absolute fluorescence quantum efficiency of 38.3%) are fabricated. CPy‐Odots are employed in time‐resolved and confocal fluorescence imaging in living Hela cells and in vivo. The green emission from the CPy‐Odots is readily differentiated from the cellular autofluorescence background because of their stronger emission intensities and longer lifetimes. Unlike other widely studied DSPE‐PEG2000 encapsulated Odots which are always distributed in cytoplasm, CPy‐Odots are located mainly in plasma membrane. In addition, the application of CPy‐Odots as a bright microangiography agent for TRFI in zebrafish is also demonstrated. Much broader application of CPy‐Odots is also prospected after further surface functionalization. Given its simplicity, high fluorescence intensity, and wide availability of TADF materials, the method can be extended to develop more excellent TADF Odots for accomplishing the challenges in future bioimaging applications.

Nanoscale Organic–Inorganic Hybrid Photosensitizers for Highly Effective Photodynamic Cancer Therapy

Recently, photodynamic therapy (PDT) has attracted significant attention as a minimally invasive approach for cancer treatment. Clinical applications of current photosensitizers are often limited by their poor water solubility, low singlet oxygen (1O2) quantum yields, long-term toxicity, instability, and complex nanostructures. Here, we report a rational design of polyhedral oligomeric silsesquioxanes (POSSs)-based porphyrin (PPP5000) used as an intrinsically nanoscale photosensitizer. In this strategy, inorganic 3D rigid block POSSs not only act as antiaggregate units but also provide conjugating reactive sites for further chemical modification. Without an additional carrier and formulation process, PPP5000 intrinsically shows high water solubility (∼40 mg/mL), good PDT efficiency, and more excellent anticancer performance compared to tetra(hydroxyphenyl)porphyrin (the parent compound of m-THPC, Foscan). Considering the organic nature of porphyrin and the biodegradable property of inorganic POSS scaffolds at physiological conditions, the present work may lead to a new generation of biodegradable and intrinsic PDT agents with overall performance superior to conventional agents in terms of 1O2 production efficiency, water solubility, structurally stability, photostability, and biocompatibility.

AIE-active conjugated polymer nanoparticles with red-emission for in vitro and in vivo imaging

A novel red-emission conjugated polymer (PBPTPE) with aggregation-induced emission (AIE) characteristics was developed from boron dipyrromethene (BODIPY) derivatives and 1,2-bis(4-ethynylphenyl)-1,2-diphenylethene via palladium-catalyzed Sonogashira coupling reaction. The resulting polymer (PBPTPE) was weakly fluorescent in dichloromethane solution, but showed bright fluorescent emission when aggregated in dichloromethane/hexane mixtures or fabricated into conjugated polymer nanoparticles (PBPTPE NPs). The nanoparticles from PBPTPE were prepared through solvent-exchange method. PBPTPE NPs possess excellent photostability, including superior photobleaching resistance, and good stability in a wide pH range. Besides, in vitro cytotoxicity and hemolysis assay indicated that PBPTPE NPs had favorable biocompatibility. Furthermore, biological evaluation and bioimaging were performed using developmental stage zebrafish embryos. From the survival and hatching rate, oxidative stress and immune-related parameters, no significant adverse effect was observed. The microangiography in zebrafish, further shows that PBPTPE NPs can be used as a bioprobe for future in vivo applications.