Ferrocene/ β-cyclodextrin based supramolecular nanogels as theranostic systems

A supramolecular redox responsive nanogel (NG) with the ability to sense cancer cells and loaded with a releasing therapeutic agent was synthesized using hostguest interactions between polyethylene glycol-grafted-β-cyclodextrin and ferrocene boronic acid. Cyclic voltammetry matched with other spectroscopy and microscopy methods provided strong indications regarding host-guest interactions and formation of the NG. Moreover, the biological properties of the NG were evaluated using fluorescence silencing, confocal laser scanning microscopy, and cell toxicity assays. Nanogel with spherical core-shell architecture and 100-200 nm sized nanoparticles showed high encapsulation efficiency for doxorubicin (DOX) and luminol (LU) as therapeutic and sensing agents. High therapeutic and sensing efficiencies were manifested by complete release of DOX and dramatic quenching of LU fluorescence triggered by 0.05 mM H2O2 (as an ROS component). The NGs showed high ROS sensitivity. Taking advantage of a high loading capacity, redox sensitivity, and biocompatibility, the NGs can be used as strong theranostic systems in inflammation-associated diseases.

Covalent Organic Frameworks as Nanocarriers for Improved Delivery of Chemotherapeutic Agents

Cancer has become one of the main causes of death worldwide. Chemotherapy as one of the main therapy modalities is very unsatisfactory. The various nanocarriers have brought new opportunities for effective tumor treatment. However, most of the current nanocarriers still suffer from low efficiency and confront significant challenges in overcoming multiple biological barriers. Compared with conventional nanocarriers, covalent organic frameworks (COFs) with unique and attractive features exhibited great potential to serve as a promising platform for anticancer drug delivery. In this review, we first summarize the strategies and challenges of nanocarriers for cancer chemotherapy and then highlight the recent advances in COF-based nanocarriers for improved delivery of chemotherapeutic agents. Finally, the challenges remaining for COF-based nanocarriers for clinical applications are outlined.

Strategies and applications of covalent organic frameworks as promising nanoplatforms in cancer therapy

Cancer nanomedicine is the best option to face the limits of conventional chemotherapy and phototherapy methods, and thus the intensive quest for new nanomaterials to improve therapeutic efficacy and safety is still underway. Owing to their low density, well-defined structures, large surface area, finely tunable pore size, and metal ion free features, covalent organic frameworks (COFs) have been extensively studied in many research fields. The recent great interest in nanoscale COFs to improve the properties of bulk COFs has led to broadening of their applicability in the biomedical field, such as nanocarriers with an outstanding loading capacity and efficient delivery of therapeutic agents, smart theranostic nanoplatforms with excellent stability, high ROS generation, light-to-heat conversion capabilities, and different response and diagnostic characteristics. The COFs and related nanoplatforms with a wide variety of designability and functionalization have opened up a new avenue for exciting opportunities in cancer therapy. Herein we review the state-of-the-art technical and scientific developments in this emerging field, focusing on the overall progress addressed so far in building versatile COF-based nanoplatforms to enhance chemotherapy, photodynamic/photothermal therapy, and combination. Future perspectives for achieving the synergistic effect of cancer elimination and clinical translation are further discussed to motivate future contributions and explore new possibilities.

pH and Redox Dual-Sensitive Covalent Organic Framework Nanocarriers to Resolve the Dilemma Between Extracellular Drug Loading and Intracellular Drug Release

Cancer poses a serious threat to human health. To enhance the efficacy of tumor chemotherapy, it is urgent to develop novel and effective nanocarriers with the ability to efficiently load and deliver anticancer drugs. Covalent organic frameworks (COF)-based nanocarriers (CONs) have exhibited great potential for drug loading due to their porous structure and high surface area. However, the function of tumor intracellular-triggered drug release has barely been integrated. Herein we first synthesized a kind of hydrazide and disulfide bonds containing building block (4,4'-Dihydrazide diphenyl disulfide, DHDS), which was used to develop a PEGylated pH and redox dual-sensitive CONs (denoted HY/SS-CONs) for efficiently loading and delivering doxorubicin (DOX). The obtained HY/SS-CONs can achieve a very high loading content of DOX and very low premature leakage at physiological condition. However, under tumor intracellular microenvironment, HY/SS-CONs with acid-cleavable hydrazone bonds, and GSH-exchangeable disulfide bonds will undergo rapid disintegration, and efficiently release DOX to kill tumor cells. The COFs-based dual-sensitive nanocarriers provide a promising solution to the dilemma of extracellular drug loading and tumor intracellular drug release.

Constructing “breathing” dynamic skeletons with extra π-conjugated adsorption sites for iodine capture

Radioiodine (¹²⁹I and ¹³¹I) emission from the nuclear waste stream has aroused enormous apprehension because of its quick diffusion and radiological contamination. Conventional porous adsorbents such as zeolites and carbon with rigid skeletons and constant pore volumes reveal a limited performance for reliable storage. Here, a series of soft porous aromatic frameworks (PAFs) with additional π-conjugated fragments is disclosed to serve as physicochemical stable media. Due to the flexibility of the tertiary amine center, the PAF products provide sufficient space for the binding sites, and thus exhibit a considerable capability for iodine capture from both gaseous and soluble environments. The obtained capacity of PAFs is ca. 1.6 times higher than that of PAF-1 which possesses similar aromatic constituents featuring an ultra-large specific surface area (BET = 5600 m² g⁻¹). The novel paradigm of dynamic frameworks is of fundamental importance for designing adsorbents to treat environmental pollution issues.

A series of soft porous aromatic frameworks (PAFs) with additional π-conjugated fragments provides sufficient space for the binding sites which serve as physicochemical stable mediums for radioiodine.

Self-assembly and self-delivery nanodrug of bortezomib: a simple approach to achieve the trade-off between functionality and druggability

A pH-responsive self-delivery nanosystem with high drug loading and outstanding stability was constructed via a simple method to deliver bortezomib.