Layer-by-layer assembled gold nanoparticles with a tunable payload of a nitric oxide photocage

Inherently nitric oxide containing polymersomes remotely regulated by NIR for improving multi-modal therapy on drug resistant cancer

The therapeutic potential of nitric oxide (NO) has been highly attractive to tumor treatment, especially for surmounting the multidrug resistance (MDR) of cancer. However, the NO-involved therapy remains extremely challenging because of the difficulty to simultaneously control the NO release rate and real-time concentration. Herein, we construct NO-containing polymersomes with high amount of NO donors inherently grown on the polymer chains to keep the stability. These polymersomes can be simultaneously loaded with photosensitizer of IR780 iodide on the membrane layer and chemotherapeutic of DOX·HCl in the lumen. NO release can be triggered by the reduction conditions, and further accelerated by remote NIR irradiation due to the increased local temperature. The instantaneous NO release with high concentration significantly inhibits the P-gp expression and sensitize the chemotherapy, thus overcoming the tumor MDR and improving the anti-tumor activity. Meanwhile, DOX·HCl release is highly promoted at the intracellular conditions because of the cleavage of acid-labile cis-aconitic amide at endo/lysosomal pH, and the improved hydrophilicity of the membrane layer after NO release. The in vivo results show that the single intravenous injection of polymersome formulation companying with NIR irradiation exerts multi-modal therapies of chemotherapy, PTT/PDT, and NO-therapy on the MCF-7/R tumor models, showing superior and combinational treatment efficacy with the complete eradication of tumors and few side effects.

Advances in inorganic-based colloidal nanovehicles functionalized for nitric oxide delivery

Nitric oxide (NO) is an important pharmaceutical agent of considerable therapeutic interest ascribed to its vasodilative, tumoricidal and antibacterial effects. Rapid development of functional nanomaterials has provided opportunities for us to achieve controllable exogenous delivery of NO. In the current review, a variety of functionalized colloidal nanovehicles that have been developed to date for nitric oxide delivery are reported. Specifically, we focus on inorganic nanomaterials such as semiconductor quantum dots, silica nanoparticles, upconversion nanomaterials, carbon/graphene nanodots, gold nanoparticles, iron oxide nanoparticles as the functional or/and supporting materials to carry NO donors. N-diazeniumdiolates, S-nitrosothiols, nitrosyl metal complexes and organic nitrates as main types of NO donors have their own unique properties and molecular structures. Conjugating the NO donors of different forms with appropriate nanomaterials results in NO delivery nanovehicles capable of releasing NO in a dose-controllable or/and on-demand manner. We also consider the therapeutic applications of those NO delivery nanovehicles, especially their applications for cancer therapy. In the end, we discuss possible future directions for developing exogenous NO delivery systems with more desired structure and improved performance. This review aims to offer the readers an overall view of the advances in functionalized colloidal nanovehicles for NO delivery. It will be attractive to scientists and researchers in the areas of material science, nanotechnology, biomedical engineering, chemical biology, etc.

Layer-by-layer modification of high surface curvature nanoparticles with weak polyelectrolytes using a multiphase solvent precipitation process

The layer-by-layer modification of ≈5 nm mercaptocarboxylic acid stabilized gold nanoparticles was studied in an effort to illustrate effective means to overcome practical issues in handling and performing surface modification of such extremely small materials. To accomplish this, each layer deposition cycle was separated into a multi-step process wherein solution pH was controlled in two distinct phases of polyelectrolyte adsorption and centrifugation. Additionally, a solvent precipitation step was introduced to make processing more amenable by concentrating the sample and exchanging solution pH before ultracentrifugation. The pH-dependent assembly on gold nanoparticles was assessed after each layer deposition cycle by monitoring the plasmon peak absorbance location, surface charge, and the percentage of nanoparticles recovered. The selection of solution pH during the adsorption phase was found to be a critical parameter to enhance particle recovery and maximize surface charge when coating with weak polyelectrolytes. One bilayer was deposited with a high yield and the modified particles exhibited enhanced colloidal stability across a broad pH range and increased ionic strength. These findings support the adoption of this multi-step processing approach as an effective and generalizable approach to improve stability of high surface curvature particles.

A mitochondrial-targeting and NO-based anticancer nanosystem with enhanced photo-controllability and low dark-toxicity

Compared to the generation of singlet oxygen in photodynamic therapy, photo-generation of nitric oxide (NO) would not be limited by the concentration of molecular oxygen. However, therapeutic applications of exogenous nitric oxide are usually limited by its short half-life and its vulnerability to many biological substances, thus straightforward and precise control over NO delivery may be critical to its therapeutic effects. Herein, we demonstrate a mitochondrial-targeting and photoactive NO-releasing system as an anticancer drug. Fabricated by covalently incorporating a photo-responsive NO-donor and a mitochondrial targeting ligand onto carbon dots, this nanosystem exhibits a multi-functional nature which combines mitochondrial-targeting, photocontrollable NO-releasing and cell imaging. Upon cellular internalization, the nanosystem could target mitochondria effectively. Furthermore, the system displays little dark toxicity under physiological temperature; but upon light irradiation, it could release NO, efficiently damage mitochondria and consequently cause prominent apoptosis of cancer cells. Moreover, evaluated by using MTT assay, this nanosystem shows high cytotoxicity towards two cancer cell lines. These observations provide new insights for exploiting NO in disease therapy.

Near-IR mediated intracellular uncaging of NO from cell targeted hollow gold nanoparticles

NIR light triggers NO delivery with unprecedented spatio-temporal control inside prostate cancer cells from surface-modified hollow gold nanoshells.