Xing-Can Shen

Graphene loading water-soluble phthalocyanine for dual-modality photothermal/photodynamic therapy via a one-step method

In this paper, we present a new and facile one-step method for the fabrication of a water-soluble graphene-phthalocyanine (GR-Pc) hybrid material by simply sonicating GR with a hydrophilic Pc, tetrasulfonic acid tetrasodium salt copper phthalocyanine (TSCuPc). In the resultant hybrid material, TSCuPc is coated on the skeleton of pristine GR via non-covalently π-π interaction, detailedly characterized by UV-vis/Raman spectra, X-ray photoelectron spectroscopy (XPS), etc. The obtained GR-Pc hybrid (GR-TSCuPc) is applied for photothermal therapy (PTT) and photodynamic therapy (PDT). In this PTT/PDT system, both GR and TSCuPc operate as multifunctional agents: GR acts as a photosensitizer carrier and PTT agent, while TSCuPc acts as a hydrophilic PDT agent. Furthermore, the results of cell viability show that the phototherapy effect of GR-TSCuPc is observably higher than that of free TSCuPc, indicating that combined noninvasive PTT/PDT exhibits better anti-cancer efficacy in vitro. Such results highlight that this work provide a facile method to develop efficacious dual-modality carbon nanoplatform for developing cancer therapeutics.

One-Step Preparation of a Water-Soluble Carbon Nanohorn/Phthalocyanine Hybrid for Dual-Modality Photothermal and Photodynamic Therapy

The biomedical applications of carbon nanomaterials, especially integrating noninvasive photothermal therapy (PTT) and photodynamic therapy (PDT), into a single system have enormous potential in cancer therapy. Herein, we present a novel and facile one-step method for the preparation of water-soluble single-walled carbon nanohorns (SWNHs) and metal phthalocyanines (MPc) hybrid for PTT and PDT. The hydrophilic MPc, tetrasulfonic acid tetrasodium salt copper phthalocyanine (TSCuPc), is coated on the surface of SWNHs via noncovalent π-π interaction using the sonication method. In this PTT/PDT nanosystem, SWNHs acts as a photosensitizer carrier and PTT agent, while TSCuPc acts as a hydrophilic and PDT agent. The EPR results demonstrated that the generated reactive oxygen species (ROS) not only from the photoinduced electron transfer process from TSCuPc to SWNHs but also from SWNHs without exciting TSCuPc to its excited state. The test of photothermal conversion proved that not only do SWNHs contribute to the photothermal therapy (PTT) effect, TSCuPc probably also contributes to that when it coats on the surface of SWNHs upon exposure to a 650-nm laser. More importantly, the results of in vitro cell viability revealed a significantly enhanced anticancer efficacy of combined noninvasive PTT/PDT, indicating that the SWNHs-TSCuPc nanohybrid is a hopeful candidate material for developing an efficient and biocompatible nanoplatform for biomedical application.

Water-soluble hyaluronic acid–hybridized polyaniline nanoparticles for effectively targeted photothermal therapy

The construction of advanced phototherapy systems with high therapeutic efficacy toward cancer and low side effects, especially targeted species, is highly desirable. Herein, we developed one kind of water-soluble hyaluronic acid-hybridized polyaniline nanoparticles (HA-PANI NPs) as a nanoplatform for photothermal therapy (PTT) with targeted specificity of a CD44-mediated cancer cell. The water-soluble HA-PANI NPs were fabricated by one-step oxidative polymerization using aniline as a polymerizable monomer and HA as a stabilizer and targeted agent, where non-covalent electrostatic interaction between the negatively charged polymer HA and the cationic polymer PANI drives the formation of HA-PANI NPs. It was demonstrated that approximately spherical HA-PANI NPs are well-dispersed in aqueous solutions, with average hydrodynamic diameters of around 100 nm. Besides, HA-PANI NPs have negligible cytotoxicity in vitro, which facilitates biomedical applications with low toxicity. We studied the in vitro photothermal cell-killing efficacy of HA-PANI NPs by MTT assay and confocal microscopy measurement. The results reveal that HA-PANI NPs can selectively kill the cancer cells of HeLa and HCT-116 cells rather than normal cells of HFF cells upon exposure to a NIR 808 nm laser. The efficient intracellular intake of the HA-PANI NPs by both HeLa and HCT-116 cells are observed, confirming their targeting ability for CD44-overexpressing cancer cells. Furthermore, the results of in vivo photothermal ablation of tumors show excellent treatment efficacy, indicating that the HA-PANI NPs can be considered as an extremely promising nanoplatform for targeted PTT of cancer.

Selective Probing of Gaseous Ammonia Using Red-Emitting Carbon Dots Based on an Interfacial Response Mechanism

Solid-state fluorescence sensing is one of the most appealing detection techniques because of its simplicity and convenience in practical operation. Herein, we report the development of a red-emitting carbon dots (RCDs)-based material as a solid-state fluorescence sensor for the selective probing of gaseous ammonia. The RCDs were prepared by a low-cost, one-step carbonization method using sugar cane bagasse as the carbon precursor. The pristine RCDs were then directly coated on polyvinylidene fluoride membrane to produce a new fluorescence sensor capable of selectively distinguishing toxic gaseous ammonia from other analyte vapors through sensitive fluorescence quenching with a low detection limit. More importantly, the interfacial response mechanism occurring on the surface of the RCDs has been studied by X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and Raman measurements. The results indicate that fluorescence quenching in the RCDs might result from ammonia-induced Michael addition through insertion of N into the C=C group and deprotonation of the carboxyl group. To the best of our knowledge, this is the first report that provides clear insight into the mechanism of surface chemistry on CDs in the solid state.

Silk fibroin-based scaffolds for tissue engineering

Silk fibroin (SF) from the Bombyx mori silkworm exhibits attractive potential applications as biomechanical materials, due to its unique mechanical and biological properties. This review outlines the structure and properties of SF, including of its biocompatibility and biodegradability. It highlights recent researches on the fabrication of various SF-based composites scaffolds that are promising for tissue engineering applications, and discusses synthetic methods of various SF-based composites scaffolds and valuable approaches for controlling cell behaviors to promote the tissue repair. The function of extracellular matrices and their interaction with cells are also reviewed here.

Combined effect of ion concentration and functional groups on surface chemistry modulated CaCO3 crystallization

The effects of self-assembled monolayer templates terminated with carboxyl, hydroxyl, amino and methyl groups (–COOH, –OH, –NH2 and –CH3) on CaCO3 crystallization are compared in aqueous solutions of low, medium and high Ca2+ concentrations. On the –COOH surface, only calcite rhombohedra are crystallized in the solutions at three different concentrations, while size, shape and orientation of the formed calcites are distinct in various Ca2+ concentration solutions. In low Ca2+ concentration solution, vaterites (111) and (200) are formed on –OH and –NH2 surfaces respectively while no crystals are observed on –CH3 surface. In high Ca2+ concentration solution, calcite (104) is formed on the –OH surface. Calcites and small amounts of vaterites and aragonites are formed on –NH2 and –CH3 surfaces. In medium concentration solutions, the results are similar to the case of high concentration with a lower density of crystals. From the view of the two well-known mechanisms for biomineralization, ion absorption and particle-based crystallization, the results in our study are discussed. Our findings can advance the understanding of CaCO3 biomineralization in nature and also supply guidance for the design of advanced biomaterials.

Poly(N-phenylglycine)-Based Nanoparticles as Highly Effective and Targeted Near-Infrared Photothermal Therapy/Photodynamic Therapeutic Agents for Malignant Melanoma

Malignant melanoma is a highly aggressive tumor resistant to chemotherapy. Therefore, the development of new highly effective therapeutic agents for the treatment of malignant melanoma is highly desirable. In this study, a new class of polymeric photothermal agents based on poly(N-phenylglycine) (PNPG) suitable for use in near-infrared (NIR) phototherapy of malignant melanoma is designed and developed. PNPG is obtained via polymerization of N-phenylglycine (NPG). Carboxylate functionality of NPG allows building multifunctional systems using covalent bonding. This approach avoids complicated issues typically associated with preparation of polymeric photothermal agents. Moreover, PNPG skeleton exhibits pH-responsive NIR absorption and an ability to generate reactive oxygen species, which makes its derivatives attractive photothermal therapy (PTT)/photodynamic therapy (PDT) dual-modal agents with pH-responsive features. PNPG is modified using hyaluronic acid (HA) and polyethylene glycol diamine (PEG-diamine) acting as the coupling agent. The resultant HA-modified PNPG (PNPG-PEG-HA) shows negligible cytotoxicity and effectively targets CD44-overexpressing cancer cells. Furthermore, the results of in vitro and in vivo experiments reveal that PNPG-PEG-HA selectively kills B16 cells and suppresses malignant melanoma tumor growth upon exposure to NIR light (808 nm), indicating that PNPG-PEG-HA can serve as a very promising nanoplatform for targeted dual-modality PTT/PDT of melanoma.

Calcium carbonate crystallization controlled by functional groups: A mini-review

Various functional groups have been suggested to play essential roles on biomineralization of calcium carbonate (CaCO3) in natural system. 2D and 3D models of regularly arranged functional groups have been established to investigate their effect on CaCO3 crystallization. This mini-review summarizes the recent progress and the future development is prospected.

Two competitive nucleation mechanisms of calcium carbonate biomineralization in response to surface functionality in low calcium ion concentration solution

Four self-assembled monolayer surfaces terminated with –COOH, –OH, –NH2 and –CH3 functional groups are used to direct the biomineralization processes of calcium carbonate (CaCO3) in low Ca2+ concentration, and the mechanism of nucleation and initial crystallization within 12u2009h was further explored. On −COOH surface, nucleation occurs mainly via ion aggregation mechanism while prenucleation ions clusters may be also involved. On −OH and −NH2 surfaces, however, nucleation forms via calcium carbonate clusters, which aggregate in solution and then are adsorbed onto surfaces following with nucleation of amorphous calcium carbonate (ACC). Furthermore, strongly negative-charged −COOH surface facilitates the direct formation of calcites, and the −OH and −NH2 surfaces determine the formation of vaterites with preferred crystalline orientations. Neither ACC nor crystalline CaCO3 is observed on −CH3 surface. Our findings present a valuable model to understand the CaCO3 biomineralization pathway in natural system where functional groups composition plays a determining role during calcium carbonate crystallization.

Water-Dispersible Prussian Blue-Hyaluronic Acid Nanocubes with Near-Infrared Photoinduced Singlet Oxygen Production and Photothermal Activities for Cancer Theranostics

Design and development of photosensitizers that can efficiently convert energy of near-infrared (NIR) laser irradiation are of major importance for cancer photoassisted therapeutics. Herein, for the first time, it is demonstrated that Prussian blue (PB), a classic coordination compound, can act as a novel photosensitizer with efficient generation of singlet oxygen and excellent photothermal conversion via NIR photoirradiation-induced energy transfer. After modification with hyaluronic acid (HA), the as-prepared HA-modified PB nanocubes (HA@PB) are highly dispersible in aqueous and physiological solutions, as well as show excellent photothermal/photodynamic activities under NIR (808 nm) photoexcitation. On the basis of these features, HA@PB is used to study their in vitro and in vivo combined therapeutic effect. Owing to the CD44 ligand of HA, HA@PB have specific uptake by CD44-positive cells in vitro and can be precisely in vivo delivered to the tumor site. HA@PB as one of the synergistically photodynamic/photothermal combination nanoplatforms could achieve excellent therapeutic efficacy with targeted specificity under the guidance of dual-modality photoacoustic/infrared thermal imaging. Hence, this work is expected to pave the way for using PB-based nanomaterials as a promising multifunctional theranostic nanoplatform in biomedical fields.