Peptide functionalized actively targeted MoS2 nanospheres for fluorescence imaging-guided controllable pH-responsive drug delivery and collaborative chemo/photodynamic therapy.

The combination of imaging and different therapeutic strategies into one single nanoplatform often demonstrates improved efficacy over monotherapy in cancer treatments. Herein, a multifunctional nanoplatform (labelled as MPRD) based on molybdenum disulfide quantum dots (MoS2 QDs) is developed to achieve enhanced antitumor efficiency by integrating fluorescence imaging, tumor-targeting and synergistic chemo/photodynamic therapy (PDT) into one system. First, polyethylene glycol (PEG)ylated MoS2 QDs (MP) with desirable stability are synthesized via a hydrothermal process using MoS2 QDs and carboxyamino-terminated oligomeric PEG as raw materials. Then, MP were conjugated with arginine-glycine-aspartic acid (RGD) peptide via amidation to form a novel nanocarrier (MPR), which possesses strong blue fluorescence, good biocompatibility and ανß3 receptor-mediated targeting ability. More importantly, MPR generated reactive oxygen species under 808 nm laser activation to realize targeted antitumor PDT. Further doxorubicin (DOX) was loaded onto MPR, which endows MPRD with localized chemotherapy and pH-responsive drug release. The MPRD exhibits improved chemotherapy performance on HepG2 cells (overexpressing integrin ανß3) owing to enhanced cellular uptake mediated by ανß3 receptor and effective drug release triggered by intracellular pH. Notably, MPRD with efficient tumor targeting ability and high chemo/PDT efficacy under NIR laser irradiation is capable of inhibiting HepG2 tumor cell growth both in vitro and in vivo, which is significantly superior to each individual therapy. These findings demonstrate that MPRD holds great potential in effective cancer therapy.

A multifunctional nanoplatform based on graphitic carbon nitride quantum dots for imaging-guided and tumor-targeted chemo-photodynamic combination therapy.

Graphitic carbon nitride quantum dots (g-CNQDs) have shown great potential in imaging, drug delivery and photodynamic therapy (PDT). However, relevant research on g-CNQDs for PDT or drug delivery has been conducted separately. Herein, we develop a g-CNQDs-based nanoplatform (g-CPFD) to achieve simultaneously imaging and chemo-photodynamic combination therapy in one system. A g-CNQDs-based nanocarrier (g-CPF) is first prepared by successively introducing carboxyamino-terminated oligomeric polyethylene glycol and folic acid onto the surface of g-CNQDs via two-step amidation. The resultant g-CPF possesses good physiological stability, strong blue fluorescence, desirable biocompatibility, and visible light-stimulated reactive oxygen species generating ability. Further non-covalently loaded doxorubicin enables the system with chemotherapy function. Compared with free doxorubicin, g-CPFD expresses more efficient chemotherapy to HeLa cells due to improved folate receptor-mediated cellular uptake and intracellular pH-triggered drug release. Furthermore, g-CPFD under visible light irradiation shows enhanced inhibition on the growth of cancer cells compared to sole chemotherapy or PDT. Thus, g-CPFD exhibits exceptional anti-tumor efficiency due to folate receptor-mediated targeting ability, intracellular pH-triggered drug release and a combined treatment effect arising from PDT and chemotherapy. Moreover, this nanoplatform benefits imaging-guided drug delivery because of inherent fluorescent properties of doxorubicin and g-CPF, hence achieving the goal of imaging-guided chemo-photodynamic combination treatments.

A sodium alginate/feather keratin composite fiber with skin-core structure as the carrier for sustained drug release.

To alleviate the serious gastrointestinal side reaction of indomethacin (IDM), sodium alginate/feather keratin (SA/FK) fiber with skin-core structure was prepared via wet spinning as the carrier for sustained release of IDM. Fourier translation infrared (FT-IR) spectroscopy was adopted to investigate the reaction mechanism among SA, FK and IDM, and Ultraviolet-visible (UV-Vis) spectroscopy was used to systematically evaluate the sustained release capacity of SA/FK fiber in three simulated fluids. Scanning electron microscope (SEM) was employed to observe the apparent morphology of SA/FK fiber. The results indicate that, release amount of IDM exhibits an increase trend along with time; the release amount of IDM reaches 80% after 12 h in colon fluid and small intestinal fluid, and is less than 20% in digestive fluid. Simultaneously, FK can effectively control the release of IDM, and with the increase of FK content, IDM release time of the carrier fiber extends.

PEGylated MoS2 quantum dots for traceable and pH-responsive chemotherapeutic drug delivery.

Since low pH value is widely observed in most of solid tumors, pH-responsive drug delivery system (DDS) can provide a general strategy for tumor-targeting therapy. In this work, a traceable and pH-responsive DDS (MoS2-PEG-DOX) based on MoS2 quantum dots (MoS2 QDs) is successfully developed by covalently grafting MoS2 QDs with diamine-terminated oligomeric polyethylene glycol (PEG) and then loading with a fluorescent antineoplastic anthracycline drug, doxorubicin (DOX). The functionalization of MoS2 QDs with PEG imparts the nanocomposite with strong blue photoluminescence, low cytotoxicity, and excellent physiological stability. The MoS2-PEG-DOX nano-assembly can be effectively taken up by U251 cells, and an accelerated DOX release is then triggered by intracellular acid condition, which in turn diminishing unwanted side effects derived by the incorporation of DOX into healthy cells. Meanwhile, the cellular uptake of the MoS2-PEG-DOX nano-assembly, consequent DOX release and the localization of nanocarrier can be real-time monitored due to the inherent stable fluorescence of MoS2-PEG and DOX. These findings demonstrate that MoS2-PEG-DOX will be promising for high treatment efficacy with minimal side effects in future therapy.

Sodium alginate/feather keratin-g-allyloxy polyethylene glycol composite phase change fiber.

In this study, the novel sodium alginate/feather keratin-g-allyloxy polyethylene glycol (SA/FK-g-APEG) composite phase change fiber was designed and fabricated via centrifugal spinning for the first time. The chemical structure of the composite fiber was characterized by FT-IF and NMR, the thermal property was characterized by DSC, and the morphology features was analyzed by SEM and EDS. The NMR result demonstrates there are chemical shifts at δ = 155.6 ppm indicating CC has been successfully introduced via acylation，and at δ = 70.06 ppm indicating that allyloxy polyethylene glycol (APEG) has been grafted onto feather keratin (FK). The DSC results show an decline in the endothermic peak related to melting of the APEG from 54.87 °C to 40.1 °C (phase change fiber), indicating the strong interaction between sodium alginate (SA) and feather keratin-g-allyloxy polyethylene glycol (FK-g-APEG). The mechanical properties test shows that the optimal spinning temperature is 40 °C, and the optimal Centrifugal speed is 500 r/min.

Preparation, characterization and catalytic properties of Pd-Fe-zeolite and Pd-Ce-zeolite composite catalysts.

Highly effective composite catalysts for removal of CO by catalytic oxidation have been designed through constructing active centers on the support of zeolite. Performances of the derived Pd-Fe-zeolite and Pd-Ce-zeolite composite catalysts for CO removal under different heterogeneous conditions were studied. The results indicate that the two kinds of promoted catalysts, including special chemical states of Pd and surface active oxygen, show high catalytic activities not only for the low temperature oxidation of CO, but also for CO electro-oxidation. The typical light-off temperatures of Pd-Fe-zeolite and Pd-Ce-zeolite for low temperature CO oxidation are 270 and 273 K. Their characteristic peak potentials for CO electro-oxidation are both around 0.70 V. The promotional effects are associated with the special interaction among Pd, modifier and zeolite, which can be firmly supported by the detailed characterizations using XRD, BET, XPS, TPD and TPR.