Carbon Dots with Intrinsic Bioactivities for Photothermal Optical Coherence Tomography, Tumor-Specific Therapy and Postoperative Wound Management.

Carbon dots (CDs) are considered as promising candidates with superior biocompatibilities for multimodel cancer theranostics. However, incorporation of exogenous components, such as targeting molecules and chemo/photo therapeutic drugs, is often required to improve the therapeutic efficacy. Herein, an "all-in-one" CDs that exhibit intrinsic bioactivities for bioimaging, potent tumor therapy, and postoperative management is proposed. The multifunctional CDs derived from gallic acid and tyrosine (GT-CDs) consist of a graphitized carbon core and N, O-rich functional groups, which endow them with a high near-infrared (NIR) photothermal conversion efficiency of 33.9% and tumor-specific cytotoxicity, respectively. A new imaging modality, photothermal optical coherence tomography, is introduced using GT-CDs as the contrast agent, offering the micrometer-scale resolution 3D tissue morphology of tumor. For cancer therapy, GT-CDs initiate the intracellular generation of reactive oxygen species in tumor cells but not normal cells, further induce the mitochondrial collapse and subsequent tumor cellular apoptosis. Combined with NIR photothermal treatment, synergistic antitumor therapy is achieved in vitro and in vivo. GT-CDs also promote the healing process of bacteria-contaminated skin wound, demonstrating their potential to prevent postoperative infection. The integrated theranostic strategy based on versatile GT-CDs supplies an alternative easy-to-handle pattern for disease management.

Black phosphorus mediated photoporation: a broad absorption nanoplatform for intracellular delivery of macromolecules.

Nanoparticle-sensitized photoporation for intracellular delivery of external compounds usually relies on the use of spherical gold nanoparticles as sensitizing nanoparticles. As they need stimulation with visible laser light, they are less suited for transfection of cells in thick biological tissues. In this work, we have explored black phosphorus quantum dots (BPQDs) as alternative sensitizing nanoparticles for photoporation with a broad and uniform absorption spectrum from the visible to the near infra-red (NIR) range. We demonstrate that BPQD sensitized photoporation allows efficient intracellular delivery of both siRNA (>80%) and mRNA (>40%) in adherent cells as well as in suspension cells. Cell viability remained high (>80%) irrespective of whether irradiation was performed with visible (532 nm) or near infrared (800 nm) pulsed laser light. Finally, as a proof of concept, we used BPQD sensitized photoporation to deliver macromolecules in cells with thick phantom tissue in the optical path. NIR laser irradiation resulted in only 1.3× reduction in delivery efficiency as compared to photoporation without the phantom gel, while with visible laser light the delivery efficiency was reduced 2×.

Cytomembrane visualization using Stokes parameter confocal microscopy.

A new, to the best of our knowledge, method for Stokes vector imaging is proposed to achieve imaging and dynamic monitoring of a non-labeled cytomembrane. In this work, a polarization state vector is described by a Stokes vector and expressed in chrominance space. A physical quantity called polarization chromaticity value (PCV) corresponding to a Stokes vector is used as the imaging parameter to perform Stokes vector imaging. By using the PCV imaging technique, the Stokes vector can be expressed in three-dimensional real space rather than in a Poincare sphere. Furthermore, a four-way Stokes parameter confocal microscopy system is designed to measure four Stokes parameters simultaneously and obtain micro-imaging. Label-free living onion cell membranes and their plasmolysis process are selected as the representative micro-anisotropy experimental analysis. It is proved that PCV imaging can perform visualization of cytomembranes, and further, microscopic orientation is demonstrated. The prospect of universal measurement of anisotropy details for analysis and diagnosis is provided.

Determination of temperature distribution in tissue for interstitial cancer photothermal therapy.

BACKGROUND: Temperature increase in tumour tissue during photothermal therapy (PTT) is a significant factor in determining the outcomes of the treatment. Therefore, controlling and optimising temperature distribution in target tissue is crucial for PTT. In this study, we developed a unique ex vivo device to study the temperature distribution during PTT to be used as a guide for the desired photothermal effects for cancer treatment. METHODS: Bovine liver tissue buried inside agarose gel served as a phantom tumour surrounded by normal tissue. A thermostatic incubator was used to simulate tissue environment in live animals. The temperature distributions were measured by thermocouples with needle probes at different locations inside the target tissue, during laser irradiation using an 805-nm laser. RESULTS: The results obtained using the ex vivo device were verified by comparing the tissue temperature directly measured in animal tumours irradiated under the same conditions. With this model, the spatial distribution of temperature in target tissue can be monitored in real time. A two-dimensional temperature distribution in target tissue allows us to establish the correlations among laser parameters, temperature distribution and tumour size. In addition, the optimal temperature range for tumour destruction and immunological stimulation was determined using metastatic rat mammary tumour model. CONCLUSION: The device and method developed in this study can provide guidance for choosing the appropriate treatment parameters for optimal photothermal effects, particularly when combined with immunotherapy, for cancer treatment.