Injectable Chitosan Hydrogels Doped with 2D Peptide Nanosheet-Drug Conjugates for Glutathione-Responsive Sustained Drug Delivery

The development of novel and effective drug delivery systems aimed at enhancing therapeutic profile and efficacy of therapeutic agents is a critical challenge in modern medicine. This study presents an intelligent drug delivery system based on self-assembled two-dimensional peptide nanosheets (2D PNSs). Leveraging the tunable properties of amino acid structures and sequences, we design a peptide with the sequence of Fmoc-FKKGSHC, which self-assembles into 2D PNSs with uniform structure, high biocompatibility, and excellent degradability. Covalent attachment of thiol-modified doxorubicin (DOX) drugs to 2D PNSs via disulfide bond results in the peptide-drug conjugates (PDCs), which is denoted as PNS-SS-DOX. Subsequently, the PDCs are encapsulated within the injectable, thermosensitive chitosan (CS) hydrogels for drug delivery. The designed drug delivery system demonstrates outstanding pH-responsiveness and sustained drug release capabilities, which are facilitated by the characteristics of the CS hydrogels. Meanwhile, the covalently linked disulfide bond within the PNS-SS-DOX is responsive to intracellular glutathione (GSH) within tumor cells, enabling controlled drug release and significantly inhibiting the cancer cell growth. This responsive peptide-drug conjugate based on a 2D peptide nanoplatform paves the way for the development of smart drug delivery systems and has bright prospects in the future biomedicine field.

Programmed-response cross-linked nanocarrier for multidrug-resistant ovarian cancer treatment

The application of numerous chemotherapeutic drugs has been limited due to poor solubility, adverse side effects, and even multidrug resistance in patients. Polymeric micelles with reversibly cross-linked structures provide a promising solution to these issues. Herein, we optimized and synthesized programable-released disulfide cross-linked micelle (PDCM) based on our previous well-defined dendrimers to deliver the antitumor drug betulinic acid (BA) and paclitaxel (PDCM@PTX) and evaluated the therapeutic efficacy of multidrug-resistant (MDR) simulative orthotopic intraperitoneal ovarian cancer mice models. Comprehensive results demonstrated that PDCM@PTX formed stable nanoparticles able to improve the pharmacokinetic profile and circulation time of PTX, allowing for increased tumor penetration. Furthermore, in the tumor microenvironment, the programable-switches (ester bonds and disulfide cross-linking) of PDCM@PTX were cleaved by the high concentration of glutathione (tumor microenvironment) and esterase (intracellular) present in the tumor, allowing for in situ release of PTX and BA, resulting in intensive therapeutic efficacy in MDR ovarian cancer.

Endogenous Copper for Nanocatalytic Oxidative Damage and Self-Protection Pathway Breakage of Cancer

Nanocatalytic medicine is one of the most recent advances in the development of nanomedicine, which catalyzes intratumoral chemical reactions to produce toxins such as reactive oxygen species in situ for cancer specific treatment by using exogenous-delivered catalysts such as Fenton agents. However, the overexpression of reductive glutathione and Cu-Zn superoxide dismutase in cancer cells will significantly counteract the therapeutic efficacy by reactive oxygen species-mediated oxidative damages. Additionally, the direct delivery of iron-based Fenton agents may arouse undesired detrimental effects such as anaphylactic reactions. In this study, instead of exogenously delivering Fenton agents, the endogenous copper ions from intracellular Cu-Zn superoxide dismutase have been employed as the source of Fenton-like agents by chelating the Cu ions from the superoxide dismutase using a common metal ion chelator, N,N,N',N'-tetrakis(2-pyridinylmethyl)-1,2-ethanediamine (TPEN), followed by the TPEN-Cu(II) chelate reduction to TPEN-Cu(I) by reductive glutathione. Briefly, TPEN was loaded in a disulfide bond-containing link poly(acrylic acid) shell-coated hybrid mesoporous silica/organosilicate (MSN@MON) nanocomposite as a reductive glutathione-responsive nanoplatform, which features inter-related triple functions: intratumoral reductive glutathione-responsive link poly(acrylic acid) disruption and TPEN release; the accompanying reductive glutathione consumption and Cu-Zn superoxide dismutase deactivation by TPEN chelating Cu ions from this superoxide dismutase; and the Fenton reaction catalyzed by TPEN-Cu(I) chelate as a Fenton-like agent generated from TPEN-Cu(II) reduction by the remaining reductive glutathione in cancer cells, thereby cutting off the self-protection pathway of cancer cells under severe oxidation stress and ensuring cancer cell apoptosis by reactive oxygen species produced by the catalytic Fenton-like reactions. Such a nanocatalyst demonstrates excellent biosafety and augmented therapeutic efficacy by simultaneous nanocatalytic oxidative damage and intrinsic protection pathway breakage of cancer cells.

Glutathione-responsive PLGA nanocomplex for dual delivery of doxorubicin and curcumin to overcome tumor multidrug resistance

Aim: This work aims to develop an injectable nano-drug delivery system to overcome tumor multidrug resistance (MDR). Methods: A drug delivery nanoplatform based on PEGylated PLGA with glutathione (GSH) responsivity was constructed for dual delivery of doxorubicin and curcumin (termed DCNP), and its MDR reversal efficiency was studied in vitro and in vivo. Results: The DCNPs exhibited a rapid drug release profile under high GSH concentration and could enhance the cellular uptake and cytotoxicity of doxorubicin to MDR cancer cells. Moreover, the DCNPs showed better biocompatibility, longer blood circulation and enhanced antitumor efficiency compared with free drugs. Conclusion: The GSH-responsive nanocarrier is believed to be a promising candidate for overcoming tumor MDR.

Impact of Amorphous SiO2 Nanoparticles on a Living Organism: Morphological, Behavioral, and Molecular Biology Implications

It is generally accepted that silica (SiO₂) is not toxic. But the increasing use of silica nanoparticles (SiO₂NPs) in many different industrial fields has prompted the careful investigation of their toxicity in biological systems. In this report, we describe the effects elicited by SiO₂NPs on animal and cell physiology. Stable and monodisperse amorphous silica nanoparticles, 25 nM in diameter, were administered to living Hydra vulgaris (Cnidaria). The dose-related effects were defined by morphological and behavioral assays. The results revealed an all-or-nothing lethal toxicity with a rather high threshold (35 nM NPs) and a LT50 of 38 h. At sub lethal doses, the morphophysiological effects included: animal morphology alterations, paralysis of the gastric region, disorganization and depletion of tentacle specialized cells, increase of apoptotic and collapsed cells, and reduction of the epithelial cell proliferation rate. Transcriptome analysis (RNAseq) revealed 45 differentially expressed genes, mostly involved in stress response and cuticle renovation. Our results show that Hydra reacts to SiO₂NPs, is able to rebalance the animal homeostasis up to a relatively high doses of SiO₂NPs, and that the physiological modifications are transduced to gene expression modulation.