Noncovalent Interaction Guided Precise Photoluminescence Regulation of Gold Nanoclusters in Both Isolate Species and Aggregate States.

Designing luminophores bright in both isolate species and aggregate states is of great importance in many emerging cutting-edge applications. However, the conventional luminophores either emit in isolate species but quench in aggregate state or emit in aggregate state but darken in isolate species. Here we demonstrate that the precise regulation of noncovalent interactions can realize luminophores bright in both isolate species and aggregate states. It is firstly discovered that the intra-cluster interaction enhances the emission of atomically precise Au25(pMBA)18 (pMBA=4-mercaptobenzoic acid), a nanoscale luminophore, while the inter-cluster interaction quenches the emission. The emission enhancing strategies are then well-designed by both introducing exogenous substances to block inter-cluster interaction and surface manipulation of Au25(pMBA)18 at the molecular level to enhance intra-cluster interaction, opening new possibilities to controllably enhance the luminophore's photoluminescence in both isolate species and aggregate states in different phases including aqueous solution, solid state and organic solvents.

Magnetic Resonance/Infrared Dual-Modal Imaging-Guided Synergistic Photothermal/Photodynamic Therapy Nanoplatform Based on Cu1.96S-Gd@FA for Precision Cancer Theranostics.

Developing new nanoplatforms for dynamically and quantitatively visualizing drug accumulation and targeting within tumors is crucial for precision cancer theranostic. However, achieving efficient tumor therapy via synergistic photothermal/photodynamic therapy (PTT/PDT) using a single excitation light source, remains a challenge. In this work, we designed Gd-surface functionalized copper sulfide nanoparticles that were modified with folic acid (FA) (Cu1.96S-Gd@FA) to overcome the above limitations and promote PTT/PDT therapeutics. Here, Cu1.96S-Gd nanoparticles were synthesized via a coprecipitation method. All samples exhibited high longitudinal relaxivity (up to 12.9 mM-1 s-1) and strong photothermal conversion efficiency (50.6%). Furthermore, the Gd ions promoted electron-hole segregation, inducing the Cu1.96S-Gd nanoparticles to generate more reactive oxygen species (ROS) than pure Cu1.96S nanoparticles. The Cu1.96S-Gd@FA enabled the targeting of folate receptor (FR) and promoted cellular uptake, consequently enhancing oncotherapy efficacy. Compared to non-targeted Cu1.96S-Gd, a higher signal enhancement for magnetic resonance (MR) imaging in vivo by Cu1.96S-Gd@FA was recorded. Given photothermal ability, the nanoparticles also could be visualized in infrared (IR) imaging. Furthermore, the nanoparticles exhibited biodegradation behavior and achieved good drug elimination performance via renal clearance. Our strategy, integrating Cu1.96S-Gd@FA nanoparticles, MR/IR dual-modal imaging, and PTT/PDT into one nanoplatform, demonstrated great potential for anti-breast cancer therapy by effectively targeting FR overexpressed breast cancer cells.

Cu2-xSe/Bi2Se3@PEG Z-scheme heterostructure: a multimode bioimaging guided theranostic agent with enhanced photo/chemodynamic and photothermal therapy.

Photodynamic therapy (PDT) can be defined as a kind of intracellular photocatalysis. Inspired by the design of photocatalysts, the construction of the heterojunction also is expected to improve the production of reactive oxygen species (ROS) for PDT. Herein, the Cu2-xSe/Bi2Se3@PEG (CB3@PEG) nano-heterostructure has been prepared by a cation-exchange process, where the interaction between the host and exchange agent is vital. CB3@PEG exhibits the near-infrared (NIR)-triggered hydroxyl radical and singlet oxygen (˙OH and 1O2) generation, which is more than 6 times in contrast with that of pure Cu2-xSe@PEG, attributed to the Z-scheme charge transfer mechanism with the high redox ability and great charge separation. Moreover, with the narrower band gap of Bi2Se3, CB3@PEG exhibits enhanced NIR harvest as well as high photothermal conversion efficiency (60.4%). Due to the Fenton reaction caused by the Cu ion, CB3@PEG is endowed with the chemodynamic therapy (CDT) and signal-enhanced T1-weight magnetic resonance imaging (MRI) capacity. In addition, the great photothermal ability and X-ray absorption coefficient provide outstanding contrast in photothermal imaging (PTI) and computerized tomography (CT) imaging. Finally, the multi-imaging combined with the synergistic treatment (PTT/CDT/PDT) makes CB3@PEG achieve enhanced efficiency in anticancer therapy.

NIR-Driven Intracellular Photocatalytic O2 Evolution on Z-Scheme Ni3S2/Cu1.8S@HA for Hypoxic Tumor Therapy.

Hypoxia in a tumor microenvironment (TME) has inhibited the photodynamic therapy (PDT) efficacy. Here, Ni3S2/Cu1.8S nanoheterostructures were synthesized as a new photosensitizer, which also realizes the intracellular photocatalytic O2 evolution to relieve hypoxia in TME and enhance PDT as well. With the narrow band gap (below 1.5 eV), the near infrared (NIR) (808 nm) can stimulate their separation of the electron-hole. The novel Z-scheme nanoheterostructures, testified by experimental data and density functional theory (DFT) calculation, possess a higher redox ability, endowing the photoexited holes with sufficient potential to oxide H2O into O2, directly. Meanwhile, the photostimulated electrons can capture the dissolved O2 to form a toxic reactive oxygen species (ROS). Moreover, Ni3S2/Cu1.8S nanocomposites also possess the catalase-/peroxidase-like activity to convert the endogenous H2O2 into ·OH and O2, which not only cause chemodynamic therapy (CDT) but also alleviate hypoxia to assist the PDT as well. In addition, owing to the narrow band gap, they possess a high NIR harvest and great photothermal conversion efficiency (49.5%). It is noted that the nanocomposites also exhibit novel biodegradation and can be metabolized and eliminated via feces and urine within 2 weeks. The present single electrons in Ni/Cu ions induce the magnetic resonance imaging (MRI) ability for Ni3S2/Cu1.8S. To make sure that the cancer cells were specifically targeted, hyaluronic acid (HA) was grafted outside and Ni3S2/Cu1.8S@HA integrated photodynamic therapy (PDT), chemodynamic therapy (CDT), and photothermal therapy (PTT) to exhibit the great anticancer efficiency for hypoxic tumor elimination.

Disrupted intracellular redox balance with enhanced ROS generation and sensitive drug release for cancer therapy.

In this paper, a nanocomposite was constructed to achieve improved photodynamic therapy (PDT) via disrupting the redox balance in cancer cells. Firstly, Sb2Se3 nanorods were synthesized as a new photosensitizer, displaying high photothermal conversion efficiency (45.2%) and reactive oxygen species (ROS) production due to the narrow band gap (1.1 eV) and a good NIR response. Moreover, the mechanism was investigated, demonstrating that dissolved O2 and photoinduced electrons manipulated ROS generation. Then, mesoporous silica was coated outside to improve the biocompatibility and to supply abundant space for the anticancer drug (doxorubicin, DOX). The sensitive Se-Se linker was grafted outside via a silane coupling reaction to block DOX molecules in the mesopores. As we know, the Se-Se group is sensitive to GSH, which can induce Se-Se linker bond breakage and targeted drug release due to the high expression of GSH in tumor cells. What is more, the consumption of intracellular GSH can also disrupt the redox balance in cancer cells, which would promote the PDT efficiency. The high-Z element of Sb possesses a high X-ray attenuation coefficient, giving the composite high contrast in CT imaging. This is associated with thermal imaging and multi-therapy (PDT/PTT/chemotherapy) to reveal the potential application to cancer treatment.