Smart Phototheranostics based on Carbon Nanohorns for Precise Imaging-Guided Post-PDT toward Residual Tumor Cells after Initial Phototherapy.

As promising photonic material, phototheranostics can be activated in the laser irradiation range of tumor with sensitivity and spatiotemporal precision. However, it is difficult to completely eradicate solid tumors due to their irregularity and limited laser irradiation area. Herein, multi-stimulus responsive HA-Ce6@SWNHs were constructed with single-walled carbon nanohorns (SWNHs) and chlorine e6 (Ce6) modified hyaluronic acid (HA) via non-covalent binding. This SWNHs-based phototheranostics not only exhibited water dispersion but also could target tumor and be activated by near-infrared light for photodynamic therapy (PDT) and photothermal therapy (PTT). Additionally, HA-Ce6@SWNHs could be degraded by hyaluronidase in residual tumor cells, causing HA-Ce6 to fall off the SWNHs surfaces to restore autofluorescence, thus precisely guiding the programmed photodynamic treatments for residual tumor cells after the initial phototherapy. Thus, this work provides a rationally designed multiple-stimulus-response strategy to develop smart SWNHs-based phototheranostics for precise PDT/PTT and post-treatment imaging-guided PDT of residual tumor cells.

An Investigation of the Organoborane/Lewis Base Pairs on the Copolymerization of Propylene Oxide with Succinic Anhydride.

The copolymerization of biorenewable succinic anhydride (SA) with propylene oxide (PO) is a promising way to synthesize biodegradable aliphatic polyesters. However, the catalytic systems for this reaction still deserve to be explored because the catalytic activity of the reported catalysts and the molecular weights of produced polyesters are unsatisfied. Herein, we investigate the copolymerization of SA with PO catalyzed by the organoborane/base pairs. The types of Lewis bases, organoboranes, and their loadings all have a large impact on the activity and selectivity of the copolymerization. High ester content of >99% was achieved when performed the PO/SA copolymerization using triethyl borane (TEB)/phosphazene base P1-t-Bu (t-BuP1) pair with a molar ratio of 1/1 at 30-80 °C. Using TEB/t-BuP1 pair with the molar ratio of 4/1 at 80 °C, the turnover of frequency (TOF) was up to 128 h-1 and clearly higher than the known TOF values (0.5-34 h-1) of the PO/SA copolymerization by previously reported catalysts. The number-average molecular weights (Mns) of the resultant polyesters reached up to 20.4 kg/mol when copolymerization was carried out using TEB/t-BuP1 (1/1, in molar ratio) at 30 °C.

Metal-Free Route to Precise Synthesis of Poly(propylene oxide) and Its Blocks with High Activity.

The fast and living ring-opening polymerization (ROP) of propylene oxide (PO) by metal-free catalysis is reported. By using triethyl borane (TEB) and organic Lewis bases (LBs, e.g.: phosphazene base, amidine and guanidine) as the catalysts, various alkyl alcohols can effectively initiate the ROP of PO, yielding tailor-made poly(propylene oxide)s (PPOs) with high regioregularity, predictable molecular weights, and narrow dispersity approaching Poisson distribution. The TEB/LB catalysts present unprecedentedly high activity (turnover frequency of up to 7500 h-1 ) and a truly living character for the polymerization, as evidenced by kinetic studies that showed fast initiation and growth, unobserved chain-transfer to PO, chain extension reactions, and the synthesis of various PPO-based block copolymers with narrow dispersities (D<1.1).

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.

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.