GSH/pH dual-responsive and HA-targeting nano-carriers for effective drug delivery and controlled release

In situ forming an injectable hyaluronic acid hydrogel for drug delivery and synergistic tumor therapy

Stimulus-responsive injectable hydrogel has the key characteristics of in situ drug-loading ability and the controlled drug release, enabling efficient delivery and precise release of chemotherapy drugs at the tumor site, thereby being used as a local drug delivery system for sustained tumor treatment. This article designed a smart responsive injectable hydrogel loaded with anti-tumor drugs and nanoparticles to achieve efficient and specific synergistic treatment of tumors. Hyaluronic acid (HA) hydrogel obtained by cross-linking HA-SH (HS) and HA-Tyr (HT) through horseradish peroxidase (HRP), and doxorubicin hydrochloride (DOX) and folic acid-polyethylene glycol-amine (FA-PEG-NH2) modified PDA (denoted as PPF) were encapsulated to construct the HS/HT@PPF/D hydrogel. The hydrogel had good biocompatibility, injectability, and could respond to multiple stimuli at the tumor site, thereby achieving controlled drug release. At the same time, PPF gave it excellent photothermal efficiency, photothermal stability and tumor targeting. In vitro and in vivo experimental results showed that the HS/HT@PPF/D hydrogel combined with near-infrared laser irradiation could significantly improve its anti-tumor effect and could almost eliminate the entire tumor mass without obvious adverse reactions. The HS/HT@PPF/D hydrogel could achieve multi-stimulus-responsive drug delivery and be used for precise chemo-photothermal synergistic tumor treatment, thus providing a new platform for local synergistic tumor treatment.

pH and GSH dual-responsive drug-controlled nanomicelles for breast cancer treatment

We developed a pH/glutathione (GSH) dual-responsive smart nano-drug delivery system to achieve targeted release of a chemotherapeutic drug at breast tumor site. Doxorubicin (DOX) was linked to polyethylene glycol (PEG) through cis-aconitic anhydride (CA) and disulfide bonds (SS) to obtain the PEG-SS-CA-DOX prodrug, which spontaneously assembled into nanomicelles with a particle size of 48 ± 0.45 nm. PEG-SS-CA-DOX micelles achieved an efficient and rapid release of DOX under dual stimulation by weak acidic pH and high GSH content of tumors, with the release amount reaching 88.0% within 48 h. Cellular uptake experiments demonstrated that PEG-SS-CA-DOX micelles could efficiently transport DOX into cells and rapidly release it in the tumor microenvironment. In addition,in vivoantitumor experiments showed that PEG-SS-CA-DOX had a high inhibition rate of 70% against 4T1 breast cancer cells along with good biosafety. In conclusion, dual-responsive smart nanomicelles can achieve tumor-targeted drug delivery and specific drug release, thus improving therapeutic efficacy of drugs.

Redox-Responsive Mesoporous Silica Nanoparticles for Cancer Treatment: Recent Updates

Mesoporous silica nanoparticles have been widely applied as carriers for cancer treatment. Among the different types of stimuli-responsive drug delivery systems, those sensitive to redox stimuli have attracted much attention. Their relevance arises from the high concentration of reductive species that are found within the cells, compared to bloodstream, which leads to the drug release taking place only inside cells. This review is intended to provide a comprehensive overview of the most recent trends in the design of redox-responsive mesoporous silica nanoparticles. First, a general description of the biological rationale of this stimulus is presented. Then, the different types of gatekeepers that are able to open the pore entrances only upon application of reductive conditions will be introduced. In this sense, we will distinguish among those targeted and those non-targeted toward cancer cells. Finally, a new family of bridged silica nanoparticles able to degrade their structure upon application of this type of stimulus will be presented.