Functional black phosphorus nanosheets for mitochondria-targeting photothermal/photodynamic synergistic cancer therapy

Tetraphenylporphine-Modified Polymeric Nanoparticles Containing NIR Photosensitizer for Mitochondria-Targeting and Imaging-Guided Photodynamic Therapy

Near-infrared (NIR) photodynamic therapy (PDT) is a promising antitumor strategy under NIR light irradiation to kill cancer cells. Mitochondria has a critical function in sustaining cellular viability and death, which is the ideal organelle for PDT. Here, we reported a tetraphenylporphine (TPP)-conjugated amphiphilic copolymer and an iodinated boron dipyrromethene photosensitizer (BDPI) with high singlet oxygen yield to form nanoparticles (PBDPI-TPP), which could realize mitochondria-targeting and improve the NIR imaging-guided PDT. The as-prepared mitochondria-targeting nanoplatform could show effective subcellular localization and bring about significant irreversible mitochondrial injury for enhanced PDT. Both in vitro and in vivo experiments revealed that the mitochondria-targeting PDT system could achieve a remarkable therapeutic effect, indicating that it is a promising nanoplatform for NIR imaging-guided PDT in cancer therapeutics.

An intelligent ZIF-8-gated polydopamine nanoplatform for in vivo cooperatively enhanced combination phototherapy

The extreme complexity and heterogeneity of fatal tumors requires the development of combination phototherapy considering the limited therapeutic efficiency of conventional monomodal photodynamic therapy (PDT) or photothermal therapy (PTT).

The extreme complexity and heterogeneity of fatal tumors requires the development of combination phototherapy considering the limited therapeutic efficiency of conventional monomodal photodynamic therapy (PDT) or photothermal therapy (PTT). However, tumor-specific drug administration and the accompanying hypoxia-restrained PDT present the main obstacles for executing an efficient combination phototherapy. Developing a highly biocompatible, tumor-specific, near infrared absorbing, and oxygen (O₂)-evolving multifunctional nanoplatform is thus crucial for an effective PDT-based combination therapy. In this contribution, a multifunctional ZIF-8-gated polydopamine nanoparticle (PDA) carrier was synthesized for simultaneously delivering a photosensitizer and a catalase (CAT) into tumor cells, thus realizing a cooperatively enhanced combination photodynamic and photothermal therapy, as systematically demonstrated in vitro and in vivo. The ZIF-8 gatekeeper facilitates the simultaneous and effective delivery of these functional payloads, and the subsequent tumor acidic pH-stimulated drug release. This leads to a significant improvement of combination efficacy by ameliorating tumor hypoxic conditions since the CAT-mediated self-sufficient O₂ generation could substantially promote an efficient PDT operation. In addition, this nanoplatform can effectively convert near infrared photoradiation into heat, resulting in thermally induced elimination of cancerous cells. As an intelligent multi-mode therapeutic nanosystem, this inorganic/organic hybrid nanosystem showed great potential for accurate cancer diagnosis and immediate therapy.

Supramolecular Nanodiscs Self-Assembled from Non-Ionic Heptamethine Cyanine for Imaging-Guided Cancer Photothermal Therapy

Supramolecular nanomedicines, which use supramolecular design to improve the precision and effectiveness of pharmaceutical practice and optimize pharmacokinetic profiles, have gathered momentum to battle cancer and other incurable diseases, for which traditional small-molecular and macromolecular drugs are less effective. However, the lack of clinical approval of supramolecular assembly-based medicine underscores the challenges facing this field. A 2D nanodisc-based supramolecular structure is formed by a non-ionic heptamethine cyanine (Cy7) dye, which generates fluorescence self-quenching but unique photothermal and photoacoustic properties. These Cy7-based supramolecular nanodiscs exhibit passive tumor-targeting properties to not only visualize the tumor by near-infrared fluorescence imaging and photoacoustic tomography but also induce photothermal tumor ablation under irradiation. Due to the nature of organic small molecule, they induce undetectable acute toxicity in mice and can be eliminated by the liver without extrahepatic metabolism. These findings suggest that the self-assembling cyanine discs represent a new paradigm in drug delivery as single-component supramolecular nanomedicines that are self-delivering and self-formulating, and provide a platform technology for synergistic clinical cancer imaging and therapy.

Enhanced photodynamic therapy based on an amphiphilic branched copolymer with pendant vinyl groups for simultaneous GSH depletion and Ce6 release

An amphiphilic branched copolymer with pendent vinyl groups was synthesized to enhance the efficacy of photodynamic therapy through “thio–ene“ click reaction for simultaneous GSH depletion and Ce6 release.

Recent progress in the augmentation of reactive species with nanoplatforms for cancer therapy

Reactive species (RS), mainly including reactive oxygen species (ROS) and reactive nitrogen species (RNS), are indispensable in a wide variety of biological processes. RS often have elevated levels in cancer cells and tumor microenvironments. They also have a dual effect on cancer: on the one hand, they promote pro-tumorigenic signaling to facilitate tumor survival and on the other hand, they promote antitumorigenic pathways to induce cell death. Excessive RS would disrupt the cellular redox homeostasis balance and show partiality as oxidants, which would cause irreversible damage to the adjacent biomolecules such as lipids, proteins and nucleic acids. The altered redox environment and the corresponding increased antioxidant capacity in cancer cells render the cells susceptible to RS-manipulated therapies, especially the augmentation of RS. With the rapid development of nanotechnology and nanomedicine, a large number of cancer therapeutic nanoplatforms have been developed to trigger RS overproduction by exogenous and/or endogenous stimulation. In this review, we highlighted the latest progress in the nanoplatforms designed for the augmentation of RS in cancer therapy. Nanoplatforms based on strategies including disabling the antioxidant defense system, photodynamic therapy (PDT), sonodynamic therapy (SDT), and chemodynamic therapy (CDT) were introduced. The crucial obstacles involved in these strategies, such as the light penetration limitation of PDT, relatively low RS release by SDT, and strict conditions of Fenton reaction-mediated CDT, were also discussed, and feasible solutions for improvement were proposed. Furthermore, synergistic therapies among individual therapeutic modalities such as chemotherapy, photothermal therapy, and RS-based dynamic therapies were overviewed, which contributed to achieving more optimal anticancer efficacy than linear addition. This review sheds light on the development of non-invasive cancer therapy based on RS manipulation and provides guidance for establishing promising cancer therapeutic platforms in clinical settings.

DNA-templated porous nanoplatform towards programmed "double-hit" cancer therapy via hyperthermia and immunogenicity activation

Photothermal therapy, assisted with long-term immunological anti-tumor effect, has great potential in clinical medical practice. Herein, a brand new DNA-template hydrothermal method was developed to prepare novel Co₉S₈ nanoplatform with outstanding hydrophily and mesoporous internal structure. Based on the mesoporous Co₉S₈ nanoplatform, MRI-guided enhanced photothermal-immunology "double-hit" synergistic cancer therapy was achieved, through the HSP90 inhibition and immunology activation effect of the loaded epigallocatechin gallate and oxaliplatin. It is noteworthy that the drugs were stepwise released from the nanoplatform under the trigger of pH and heat, respectively. More importantly, the high efficient synergistic cancer therapy and long-term immunological anti-tumor effect were confirmed in vivo. The developed porous nanoplatform, taking accounts of both high efficient tumor ablation and long-term anti-tumor effect, provide a new strategy to the development of next generation nanomedicine for clinical cancer treatment.

Polydopamine-Based Nanocarriers for Photosensitizer Delivery

Photodynamic therapy (PDT) has emerged as a non-invasive modality for treating tumors while a photosensitizer (PS) plays an indispensable role in PDT. Nevertheless, free PSs are limited by their low light stability, rapid blood clearance, and poor water solubility. Constructing a nanocarrier delivering PSs is an appealing and potential way to solve these issues. As a melanin-like biopolymer, polydopamine (PDA) is widely utilized in biomedical applications (drug delivery, tissue engineering, and cancer therapy) for its prominent properties, including favorable biocompatibility, easy preparation, and versatile functionality. PDA-based nanocarriers are thus leveraged to overcome the inherent shortcomings of free PSs. In this Mini-Review, we will firstly present an overview on the recent developments of PDA nanocarriers delivering PSs. Then, we introduce three distinctive strategies developed to combine PSs with PDA nanocarriers. The advantages and disadvantages of each strategy will be discussed. Finally, the current challenges and future opportunities of PDA-based PS nanocarriers will also be addressed.

Cholesterol-Modified Black Phosphorus Nanospheres for the First NIR-II Fluorescence Bioimaging

Black phosphorus (BP) nanostructures with unique layer-dependent properties have been extensively applied in the fields of electronic devices, energy conversion and storage, and nanomedicine. As a narrow band gap semiconductor, they are expected to show strong second near-infrared (NIR-II) fluorescence. However, there is no report on the NIR-II fluorescence of free-standing BP nanostructures, which have great potential in the NIR-II fluorescence bioimaging because of their excellent biocompatibility and biodegradability. Here, for the first time, we report that the BP nanoparticles modified with cholesterol exhibit strong NIR-II fluorescence and can be encapsulated with the PEGylated lipid to form BP@lipid-PEG nanospheres for in vitro and in vivo NIR-II imaging. The resultant BP@lipid-PEG nanospheres exhibit broad emissions from 900 to 1650 nm under excitation by an 808 nm laser and have 8% quantum yield of that of standard dye IR-26. We also show that the NIR-II fluorescence image acquired with emission beyond 1400 nm has the sharpest contrast and can be used to in situ measure the diameter of blood vessels. In addition to NIR-II fluorescence imaging, we also show the potential of BP@lipid-PEG nanospheres in photoacoustic (PA) imaging. Both the long-wavelength NIR-II fluorescence imaging and PA imaging reveal that the as-fabricated BP@lipid-PEG nanospheres can be gradually metabolized by the liver in 48 h, thus making them promising for bioapplications.