One-Pot Synthesis of Affordable Redox-Responsive Drug Delivery System Based on Trithiocyanuric Acid Nanoparticles

Redox-responsive drug delivery systems present a promising avenue for drug delivery due to their ability to leverage the unique redox environment within tumor cells. In this work, we describe a facile and cost-effective one-pot synthesis method for a redox-responsive delivery system based on novel trithiocyanuric acid (TTCA) nanoparticles (NPs). We conduct a thorough investigation of the impact of various synthesis parameters on the morphology, stability, and loading capacity of these NPs. The great drug delivery potential of the system is further demonstrated in vitro and in vivo by using doxorubicin as a model drug. The developed TTCA-PEG NPs show great drug delivery efficiency with minimal toxicity on their own both in vivo and in vitro. The simplicity of this synthesis, along with the promising characteristics of TTCA-PEG NPs, paves the way for new opportunities in the further development of redox-responsive drug delivery systems based on TTCA.

Cysteine-Based Redox-Responsive Nanoparticles for Fibroblast-Targeted Drug Delivery in the Treatment of Myocardial Infarction

Upon myocardial infarction (MI), activated cardiac fibroblasts (CFs) begin to remodel the myocardium, leading to cardiac fibrosis and even heart failure. No therapeutic approaches are currently available to prevent the development of MI-induced pathological fibrosis. Most pharmacological trials fail from poor local drug activity and side effects caused by systemic toxicity, largely due to the lack of a heart-targeted drug delivery system that is selective for activated CFs. Here, we developed a reduced glutathione (GSH)-responsive nanoparticle platform capable of targeted delivering of drugs to activated CFs within the infarct area of a post-MI heart. Compared with systemic drug administration, CF-targeted delivery of PF543, a sphingosine kinase 1 inhibitor identified in a high-throughput antifibrotic drug screening, had higher therapeutic efficacy and lower systemic toxicity in a MI mouse model. Our results provide a CF-targeted strategy to deliver therapeutic agents for pharmacological intervention of cardiac fibrosis.

Reduction-responsive polymers for drug delivery in cancer therapy-Is there anything new to discover?

Among various types of stimuli-responsive drug delivery systems, reduction-responsive polymers have attracted great interest. In general, these systems have high stability in systemic circulation, however, they can respond quickly to differences in the concentrations of reducing species in specific physiological sites associated with a pathology. This is a particularly relevant strategy to target diseases in which hypoxic regions are present, as polymers which are sensitive to in-situ expressed antioxidant species can, through a local response, release a therapeutic at high concentration in the targeted site, and thus, improve the selectivity and efficacy of the treatment. At the same time, such reduction-responsive materials can also decrease the toxicity and side effects of certain drugs. To date, polymers containing disulfide linkages are the most investigated of the class of reduction-responsive nanocarriers, however, other groups such as selenide and diselenide have also been used for the same purpose. In this review article, we discussed the rationale behind the development of reduction-responsive polymers as drug delivery systems and highlight examples of recent progress. We include the most popular design methods to generate reduction-responsive polymeric carriers and their applications in cancer therapy, and question what areas may still need to be explored in a field with already a very large number of research articles. Finally, we consider the main challenges associated with the clinical translation of these nanocarriers and the future perspectives in this area. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Redox-Responsive Self-Assembled Nanoparticles for Cancer Therapy

Chemotherapy, combined with other treatments, is widely applied in the clinical treatment of cancer. However, deficiencies inherited from the traditional route of administration limit its successful application. With the development of nanotechnology, a series of smart nanodelivery systems have been developed to utilize the unique tumor environment (pH changes, different enzymes, and redox potential gradients) and exogenous stimuli (thermal changes, magnetic fields, and light) to improve the curative effect of anticancer drugs. In this review, endogenous and exogenous stimuli are briefly introduced. Among these stimuli, various redox-sensitive linkages are primarily described in detail, and their application with self-assembled nanoparticles is recounted. Finally, the application of redox-responsive self-assembled nanoparticles in cancer therapy is summarized.

Enhanced Anti-Glioma Efficacy by Borneol Combined With CGKRK-Modified Paclitaxel Self-Assembled Redox-Sensitive Nanoparticles

The serious therapeutic obstacles to glioma treatment include poor penetration across the blood-brain barrier (BBB) and low accumulation of therapeutic drugs at tumor sites. In this study, borneol combined with CGKRK peptide (a ligand of the heparan sulfate which overexpress on the glioma cells) modified paclitaxel prodrug self-assembled redox-responsive nanoparticles (CGKRK-PSNPs) were hypothesized to enhance the BBB penetration ability and active tumor targeting efficiency, respectively. The resulting CGKRK-PSNPs possessed a spherical shape with a small particle size (105.61 ± 1.53 nm) and high drug loading for PTX (54.18 ± 1.13%). The drug release behavior proved that CGKRK-PSNPs were highly sensitive to glutathione (GSH) redox environment. The in vitro cell experiments suggested that CGKRK-PSNPs significantly increased the cellular uptake and cytotoxicity of U87MG cells, meanwhile CGKRK-PSNPs showed the low cytotoxicity against BCEC cells. Combined with borneol, CGKRK-PSNPs exhibited enhanced transportation across in vitro BBB model. In intracranial U87MG glioma-bearing nude mice, the higher accumulation of CGKRK-PSNPs combined with borneol was observed through real-time fluorescence image. Moreover, the in vivo anti-glioma results confirmed that CGKRK-PSNPs combined with borneol could improve the anti-glioma efficacy with the prolonged medium survival time (39 days). In conclusion, the collaborative strategy of CGKRK-PSNPs combined with borneol provided a promising drug delivery routine for glioblastoma therapy.

Ultrasensitive GSH-Responsive Ditelluride-Containing Poly(ether-urethane) Nanoparticles for Controlled Drug Release

A novel ultrasensitive redox-responsive system for the controlled release of doxorubicin (DOX) was fabricated by ditelluride-containing poly(ether-urethane) copolymers. In this study, the ditelluride group was introduced for the first time into water-soluble copolymers used for drug delivery. Doxorubicin loaded in the copolymer nanoparticles can be released in a controlled manner through the cleavage of ditelluride bonds by glutathione (GSH). The ditelluride-containing poly(ether-urethane) nanoparticles were demonstrated to be biocompatible as drug delivery vehicles, therefore opening a new avenue in drug delivery systems for chemotherapy. Furthermore, the in vitro and in vivo studies revealed that the DOX-loaded ditelluride-containing poly(ether-urethane) nanoparticles exhibited efficient uptake in cancer cells, specific tumor targeting and antitumor activity, indicating their excellent potential as novel nanocarriers for drug delivery and cancer therapy.