Self-Activating Therapeutic Nanoparticle: A Targeted Tumor Therapy Using Reactive Oxygen Species Self-Generation and Switch-on Drug Release

Engineered triphenylphosphonium-based, mitochondrial-targeted liposomal drug delivery system facilitates cancer cell killing actions of chemotherapeutics

In addition to their classical role in ATP generation, mitochondria also contribute to Ca2+ buffering, free radical production, and initiation of programmed cell death. Mitochondrial dysfunction has been linked to several leading causes of morbidity and mortality worldwide including neurodegenerative, metabolic, and cardiovascular diseases as well as several cancer subtypes. Thus, there is growing interest in developing drug-delivery vehicles capable of shuttling therapeutics directly to the mitochondria. Here, we functionalized the conventional 10,12-pentacosadiynoic acid/1,2-dimyristoyl-sn-glycero-3-phosphocholine (PCDA/DMPC)-based liposome with a mitochondria-targeting triphenylphosphonium (TPP) cationic group. A fluorescent dansyl dye (DAN) group was also included for tracking mitochondrial drug uptake. The resultant PCDA-TPP and PCDA-DAN conjugates were incorporated into a 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)-based lipid bilayer, and these modified liposomes (Lip-DT) were studied for their cellular toxicity, mitochondrial targeting ability, and efficacy in delivering the drug Doxorubicin (Dox) to human colorectal carcinoma (HCT116) and human breast (MCF7) cancer cells in vitro. This Lip-DT-Dox exhibited the ability to shuttle the encapsulated drug to the mitochondria of cancer cells and triggered oxidative stress, mitochondrial dysfunction, and apoptosis. The ability of Lip-DT-Dox to trigger cellular toxicity in both HCT116 and MCF7 cancer cells was comparable to the known cell-killing actions of the unencapsulated drug (Dox). The findings in this study reveal a promising approach where conventional liposome-based drug delivery systems can be rendered mitochondria-specific by incorporating well-known mitochondriotropic moieties onto the surface of the liposome.

A transient vesicular glue for amplification and temporal regulation of biocatalytic reaction networks

Regulation of enzyme activity and biocatalytic cascades on compartmentalized cellular components is key to the adaptation of cellular processes such as signal transduction and metabolism in response to varying external conditions. Synthetic molecular glues have enabled enzyme inhibition and regulation of protein-protein interactions. So far, all the molecular glue systems based on covalent interactions operated under steady-state conditions. To emulate dynamic biological processes under dissipative conditions, we introduce herein a transient supramolecular glue with a controllable lifetime. The transient system uses multivalent supramolecular interactions between guanidinium group-bearing surfactants and adenosine triphosphate (ATP), resulting in bilayer vesicle structures. Unlike the conventional chemical agents for dissipative assemblies, ATP here plays the dual role of providing a structural component for the assembly as well as presenting active functional groups to "glue" enzymes on the surface. While gluing of the enzymes on the vesicles achieves augmented catalysis, oscillation of ATP concentration allows temporal control of the catalytic activities similar to the dissipative cellular nanoreactors. We further demonstrate temporal upregulation and control of complex biocatalytic reaction networks on the vesicles. Altogether, the temporal activation of biocatalytic cascades on the dissipative vesicular glue presents an adaptable and dynamic system emulating heterogeneous cellular processes, opening up avenues for effective protocell construction and therapeutic interventions.

Iron-silicate-coated porous silicon nanoparticles for in situ ROS self-generation

Porous silicon nanoparticles (pSiNPs) have gained attention from drug delivery systems (DDS) due to their biocompatibility, high drug-loading efficiency, and facile surface modification. To date, many surface chemistries of pSiNPs have been developed to maximize the merits and overcome the drawbacks of pSiNPs. In this work, we newly disclosed a formulation, iron-silicate-coated pSiNPs (Fe-pSiNPs-NCS), using the surface modification method with iron-silicate and 3-isothiocyanatopropyltriethoxysilane (TEPITC). Fe-pSiNPs-NCS demonstrated effective reactive-oxygen species (ROS) self-generation ability via a Fenton-like reaction of iron-silicate and in situ hydrogen peroxide (H₂O₂) generation of TEPITC on the surface of pSiNPs, resulting in excellent anticancer effect in U87MG cancer cells. Moreover, we confirmed that Fe-pSiNPs-NCS could be used as a drug delivery carrier as it was proven that anticancer drugs (doxorubicin, SN-38) were loaded into Fe-pSiNPs-NCS with high-loading efficiency. These findings could offer efficient strategies for developing nanotherapeutics in biomedical fields.

Chemical Sensors Based on Molecularly Imprinted Polymers Can Determine Drug Release Kinetics from Nanocarriers without Filtration, Centrifugation, and Dialysis Steps

With the development of drug delivery systems, the use of nanomaterials for slow, targeted, and effective drug release has grown significantly. To ensure the quality of performance, it is essential to obtain drug release profiles from therapeutic nanoparticles prior to in vivo testing. Typically, the methods of monitoring the drug release profile from nanoparticle drug delivery systems include one or more filtration, separation, and sampling steps, with or without membrane, which cause several systematic errors and make the process time-consuming. Here, the release rate of doxorubicin as a model drug from liposome as a nanocarrier was determined via highly selective binding of released doxorubicin to the doxorubicin-imprinted electropolymerized polypyrrole as a molecularly imprinted polymer (MIP). Incubation of the MIP-modified substrate with imprinted cavities complementary to doxorubicin molecules in the releasing medium leads to the binding of released doxorubicin molecules to cavities. The drug trapped in the cavities is determined by one of the analytical methods depending on its signaling properties. In this work, due to the favorable electrochemical properties of doxorubicin, the voltammetry method was used for quantitative analysis of released doxorubicin. The voltammetric oxidation peak current intensity of doxorubicin on the surface of the electrode was enhanced by increasing the release time. This membranelle platform allows fast, reliable, and simple monitoring of drug release profiles without any sample preparation, filtration, and centrifugation in buffer and blood serum samples.

Dual-prodrug cascade activation for chemo/chemodynamic mutually beneficial combination cancer therapy

The combination of chemodynamic therapy (CDT) and chemotherapy has shown promise for achieving improved cancer treatment outcomes. However, due to the lack of synergy rationale, a simple one-plus-one combination therapy remains suboptimal in overcoming the obstacles of each treatment approach. Herein, we report a nanoplatform consisting of a pH-sensitive ferrocene- and cinnamaldehyde-based polyprodrug and a hydrogen peroxide-responsive doxorubicin (DOX) prodrug. Under an acidic tumor environment, the cinnamaldehyde polyprodrug will be activated to release free cinnamaldehyde, which can increase the intracellular hydrogen peroxide level and enhance the Fenton reaction. Subsequently, due to the collapse of nanoparticle structures, the DOX prodrug will be released and activated under a hydrogen peroxide stimulus. Meanwhile, the quinone methide produced during DOX prodrug activation can consume glutathione, an important antioxidant, and thus in turn enhance the efficacy of CDT. This design of a nanoplatform with dual-prodrug cascade activation provides a promising mutually beneficial cooperation mode between chemotherapy and CDT for enhancing antitumor efficacy.

Paclitaxel-nanocrystals-loaded network thermosensitive hydrogel for localised postsurgical recurrent of breast cancer after surgical resection

The recurrence of cancer after local surgery has been a difficult problem in the clinic for a long time. In recent years, local treatment via drug-loaded thermosensitive hydrogels have become a promising strategy to prevent cancer recurrence. Thus, a thermosensitive hydrogel based on poloxamer 407, poloxamer 188 and the bioadhesive excipient carbomer 974P was designed to locally release paclitaxel and prevent local tumour recurrence after direct smearing of the hydrogel at the site of injury in the surgical cavity. To improve the local drug concentration, paclitaxel was prepared into nanocrystals via a wet mill process. A series of studies were performed on this paclitaxel nanocrystal thermosensitive hydrogel (PTX-NCS-gel), including examination of its rheological properties and in vitro release and dissolution studies. Moreover, a postoperative tumour recurrence mouse model was established to evaluate the antitumour effects of this thermosensitive hydrogel. The results showed that PTX-NCS-gel had a clear, regular network structure with excellent temperature sensitivity and could be gelated within minutes at 33.1 °C. Additionally, the rheological property investigation indicated that the hydrogel has proper viscoelasticity and self-recovery ability. In vivo imaging showed that PTX-NCS-gel inhibited both local tumour recurrence and distant metastasis. Moreover, PTX-NCS-gel has the following advantages: it is more convenient to administer, avoids strong allergic responses, and has fewer side effects on the liver and spleen. This hydrogel has the potential to serve as a powerful auxiliary medication to prevent postoperative local tumour recurrence.

Thermally induced silane dehydrocoupling on porous silicon nanoparticles for ultra-long-acting drug release

Here, we report an ultra-long-acting drug release nano-formulation based on porous silicon nanoparticles (pSiNPs) that are prepared by thermally induced silane dehydrocoupling and lipid-coating. This robust formulation offers the ability to release an anticancer drug, for up to 2 weeks, in various biological environments; pH 7.4 buffer, cancer cells, and tumor xenograft model.

Hyaluronan-fullerene/AIEgen nanogel as CD44-targeted delivery of tirapazamine for synergistic photodynamic-hypoxia activated therapy

The therapeutic effect of oxygen-concentration-dependent photodynamic therapy (PDT) can be diminished in the hypoxic environment of solid tumours, the effective solution to this problem is utilising hypoxic-activated bioreduction therapy (BRT). In this research, a biocompatible HA-C60/TPENH₂nanogel which can specifically bind to CD44 receptor was developed for highly efficient PDT-BRT synergistic therapy. The nanogel was degradable in acidic microenvironments of tumours and facilitated the release of biological reduction prodrug tirapazamine (TPZ). Importantly, HA-C60/TPENH₂nanogel produced reactive oxygen species and consumed oxygen content in the cell to activate TPZ, leading to higher cytotoxicity than the free TPZ did. The intracellular observation of nanogel indicated that the HA-C60/TPENH₂nanogel was self-fluorescence for cell imaging. This study applied PDT-BRT to design smart HA-based nanogel with targeted delivery, pH response, and AIEgen feature for efficient cancer therapy.