Intrathoracic Endotracheal Metastasis from Nasopharyngeal Carcinoma: A First Case Report and Review of the Literature

Intrathoracic endotracheal metastasis from a very distant site is extremely rare. We report the first case of such a disease in a 68-year-old man with nasopharyngeal carcinoma who presented with a cough and hemoptysis 34 months after finishing radiotherapy. Prior to tracheal metastasis, he developed a solitary metastasis in the lung and underwent chemotherapy followed by radiotherapy. Computed tomography showed the presence of an enlarged lymph node in the para-aortic arch. Fiberoptic bronchoscopy revealed an endotracheal tumor 1 cm above the carina. Histological and immunohistochemical analyses confirmed its nasopharyngeal origin. He was treated with conventional radiotherapy and three-dimensional conformal radiotherapy; complete tumor remission was achieved. He died of nonmalignant disease with no signs of tumor recurrence 2 years after treatment completion. Radiotherapy may be an appropriate management approach to achieve long-term tumor control for this disease

Optical bulk-boundary dichotomy in a quantum spin Hall insulator

The bulk-boundary correspondence is a key concept in topological quantum materials. For instance, a quantum spin Hall insulator features a bulk insulating gap with gapless helical boundary states protected by the underlying Z2 topology. However, the bulk-boundary dichotomy and distinction are rarely explored in optical experiments, which can provide unique information about topological charge carriers beyond transport and electronic spectroscopy techniques. Here, we utilize mid-infrared absorption micro-spectroscopy and pump-probe micro-spectroscopy to elucidate the bulk-boundary optical responses of Bi4Br4, a recently discovered room-temperature quantum spin Hall insulator. Benefiting from the low energy of infrared photons and the high spatial resolution, we unambiguously resolve a strong absorption from the boundary states while the bulk absorption is suppressed by its insulating gap. Moreover, the boundary absorption exhibits a strong polarization anisotropy, consistent with the one-dimensional nature of the topological boundary states. Our infrared pump-probe microscopy further measures a substantially increased carrier lifetime for the boundary states, which reaches one nanosecond scale. The nanosecond lifetime is about one to two orders longer than that of most topological materials and can be attributed to the linear dispersion nature of the helical boundary states. Our findings demonstrate the optical bulk-boundary dichotomy in a topological material and provide a proof-of-principal methodology for studying topological optoelectronics.Comment: 26 pages, 4 figure

In Vivo Biodistribution of Mixed Shell Micelles with Tunable Hydrophilic/Hydrophobic Surface

The miserable targeting performance of nanocarriers for cancer therapy arises largely from the rapid clearance from blood circulation and the major accumulation in the organs of the reticuloendothelial system (RES), leading to inefficient enhanced permeability and retention (EPR) effect after intravenous injection (i.v.). Herein, we reported an efficient method to prolong the blood circulation of nanoparticles and decrease their deposition in liver and spleen. In this work, we fabricated a series of mixed shell micelles (MSMs) with approximately the same size, charge and core composition but with varied hydrophilic/hydrophobic ratios in the shell through spontaneously self-assembly of block copolymers poly­(ethylene glycol)-<i>block</i>-poly­(l-lysine) (PEG-<i>b</i>-PLys) and poly­(<i>N</i>-isopropylacrylamide)-<i>block</i>-poly­(aspartic acid) (PNIPAM-<i>b</i>-PAsp) in aqueous medium. The effect of the surface heterogeneity on the in vivo biodistribution was systematically investigated through in vivo tracking of the ¹²⁵I-labeled MSMs determined by Gamma counter. Compared with single PEGylated micelles, some MSMs were proved to be significantly efficient with more than 3 times lower accumulation in liver and spleen and about 6 times higher concentration in blood at 1 h after i.v.. The results provide us a novel strategy for future development of long-circulating nanocarriers for efficient cancer therapy

Targeted Chemo-Photodynamic Combination Platform Based on the DOX Prodrug Nanoparticles for Enhanced Cancer Therapy

Chemo-photodynamic combination therapy has been received widespread attention in cancer treatment due to its excellent characteristics, such as reducing the adverse side effects of chemo-drugs and improving the therapeutic effects for various cancers. In this study, RGD and DOX was conjugated to PEG by thiol–ene addition and Schiff’s base reaction, respectively, to prepare the targeted and pH-sensitive antitumor prodrug nanoparticles (RGD-PEG-DOX NPs, RGD-NPs). Subsequently, the photosensitizer chlorin e6 (Ce6) was encapsulated into RGD-NPs, thus obtaining a simple and efficient chemo-photodynamic combination platform (RGD-PEG-DOX/Ce6 NPs, RGD-NPs/Ce6). This nanoparticle possessed high drug loading property of both the chemo-drug and photosensitizer and could simultaneously release them under the mild acidic microenvironment of cancer cells, which was expected to realize the synchronization therapy of chemotherapy and photodynamic therapy (PDT). Compared with free DOX and Ce6, RGD-NPs/Ce6 could significantly improve the cellular uptake capacities of DOX and Ce6, resulting in the increased contents of ROS in cancer cells and effective cytotoxicity for tumor cells (MDA-MB-231 cells and MCF-7 cells) upon a laser radiation. The in vivo experiment showed that RGD-NPs/Ce6 displayed superior tumor targeting, accumulation, and retention ability than the other groups (free DOX, free Ce6 and NPs/Ce6), and thus significantly enhancing the antitumor effect in vivo with a laser radiation. In addition, the cardiotoxicity induced by DOX was thoroughly wiped out after being loaded and delivered by the nanoparticles according to the pathological analysis. Therefore, the targeted chemo-photodynamic combination therapeutic platform may be a promising candidate for enhanced cancer therapy

Self-Regulated Multifunctional Collaboration of Targeted Nanocarriers for Enhanced Tumor Therapy

Exploring ideal nanocarriers for drug delivery systems has encountered unavoidable hurdles, especially the conflict between enhanced cellular uptake and prolonged blood circulation, which have determined the final efficacy of cancer therapy. Here, based on controlled self-assembly, surface structure variation in response to external environment was constructed toward overcoming the conflict. A novel micelle with mixed shell of hydrophilic poly­(ethylene glycol) PEG and pH responsive hydrophobic poly­(β-amino ester) (PAE) was designed through the self-assembly of diblock amphiphilic copolymers. To avoid the accelerated clearance from blood circulation caused by the surface exposed targeting group c­(RGDfK), here c­(RGDfK) was conjugated to the hydrophobic PAE and hidden in the shell of PEG at pH 7.4. At tumor pH, charge conversion occurred, and c­(RGDfK) stretched out of the shell, leading to facilitated cellular internalization according to the HepG2 cell uptake experiments. Meanwhile, the heterogeneous surface structure endowed the micelle with prolonged blood circulation. With the self-regulated multifunctional collaborated properties of enhanced cellular uptake and prolonged blood circulation, successful inhibition of tumor growth was achieved from the demonstration in a tumor-bearing mice model. This novel nanocarrier could be a promising candidate in future clinical experiments

Silver-Decorated Polymeric Micelles Combined with Curcumin for Enhanced Antibacterial Activity

Because of the mounting prevalence of complicated infections induced by multidrug-resistant bacteria, it is imperative to develop innovative and efficient antibacterial agents. In this work, we design a novel polymeric micelle for simultaneous decorating of silver nanoparticles and encapsulating of curcumin as a combination strategy to improve the antibacterial efficiency. In the constructed combination system, silver nanoparticles were decorated in the micellar shell because of the in situ reduction of silver ions, which were absorbed by the poly­(aspartic acid) (PAsp) chains in the shell. Meanwhile, natural curcumin was encapsulated into the poly­(ε-caprolactone) (PCL) core of the micelle through hydrophobic interaction. This strategy could prevent aggregation of silver nanoparticles and improve the water solubility of curcumin at the same time, which showed enhanced antibacterial activity toward Gram-negative <i>P.aeruginosa</i> and Gram-positive <i>S.aureus</i> compared with sliver-decorated micelle and curcumin-loaded micelle alone, due to the cooperative antibacterial effects of the silver nanoparticles and curcumin. Furthermore, the achieved combinational micelles had good biocompatibility and low hemolytic activity. Thus, our study provides a new pathway in the rational design of combination strategy for efficiently preventing the ubiquitous bacterial infections