Thermo-Responsive Hydrogels Encapsulating Targeted Core-Shell Nanoparticles as Injectable Drug Delivery Systems

Development of a mucoadhesive drug delivery system and its interaction with gastric cells

Drugs that are designed for local treatment of gastric diseases require increased gastric residence time for prolonged action and increased efficacy. In this study, we report a mucoadhesive drug delivery system that was developed to fulfill these requirements. Alginate nanoparticles were synthesized by water-in-oil emulsification followed by external gelation and then coated with the mucoadhesive polymer Eudragit RS100. The formulated nanoparticles had a mean size of 219 nm and positive charge. A peptide, as a model drug, was loaded onto the nanoparticles with an encapsulation efficiency of 58%. The release of the model drug from the delivery system was pH-independent and lasted for 7 days. The periodic acid-Schiff stain assay indicated 69% mucin interaction for the nanoparticles, which were also capable of diffusion through artificial mucus. The nanoparticles were not toxic to gastric epithelial cells and can be internalized by the cells within 4 h. The adsorption of nanoparticles onto mucus-secreting gastric cells was found to be correlated with cell number. The delivery system developed in this study is intended to be loaded with active therapeutic agents and has the potential to be used as an alternative drug delivery strategy for the treatment of gastric related diseases.

Curcumin-loaded gold nanoparticles with enhanced antibacterial efficacy and wound healing properties in diabetic rats

Diabetic wounds pose a significant global health challenge. Although curcumin exhibits promising wound healing and antibacterial properties, its clinical potential is limited by low aqueous solubility, and poor tissue penetration. This study aimed to address these challenges and enhance the wound healing efficacy of curcumin by loading it onto gold nanoparticles (AuNPs). The properties of the AuNPs, including particle size, polydispersity index (PDI), zeta potential, percent drug entrapment efficiency (%EE) and UV-Vis spectra were significantly influenced by the curcumin/gold chloride molar ratio used in the synthesis of AuNPs. The optimal formulation (F2) exhibited the smallest particle size (41.77 ± 6.8 nm), reasonable PDI (0.59 ± 0.17), high %EE (94.43 ± 0.25 %), a moderate zeta potential (-8.44 ± 1.69 mV), and a well-defined surface Plasmon resonance peak at 526 nm. Formulation F2 was incorporated into Pluronic® F127 gel to facilitate its application to the skin. Both curcumin AuNPs solution and gel showed sustained drug release and higher skin permeation parameters compared with the free drug solution. AuNPs significantly enhanced curcumin's antibacterial efficacy by lowering the minimum inhibitory concentrations and enhancing antibacterial biofilm activity against various Gram-positive and Gram-negative bacterial strains. In a diabetic wound rat model, AuNPs-loaded curcumin exhibited superior wound healing attributes compared to the free drug. Specifically, it demonstrated improved wound healing percentage, reduced wound oxidative stress, increased wound collagen deposition, heightened anti-inflammatory effects, and enhanced angiogenesis. These findings underscore the potential of AuNPs as efficacious delivery systems of curcumin for improved wound healing applications.

Self-enhanced PTX@HSA-HA loaded functionalized injectable hydrogel for effective local chemo-photothermal therapy in breast cancer

Breast cancer is a malignant tumor that poses a significant threat to women's health and single therapy fails to play a good oncological therapeutic effect. Synergistic treatment with multiple strategies may make up for the deficiencies and has gained widespread attention. In this study, sulfhydryl-modified hyaluronic acid (HA-SH) was covalently crosslinked with polydopamine (PDA) via a Michael addition reaction to develop an injectable hydrogel, in which PDA can be used not only as a matrix but also as a photothermal agent. After HSA and paclitaxel were spontaneously organized into nanoparticles via hydrophobic interaction, hyaluronic acid with low molecular weight was covalently linked to HSA, thus conferring effectively delivery. This photothermal injectable hydrogel incorporates PTX@HSA-HA nanoparticles, thereby initiating a thermochemotherapeutic response to target malignancy. Our results demonstrated that this injectable hydrogel possesses consistent drug delivery capability in a murine breast cancer model, collaborating with photothermal therapy to effectively suppress tumor growth, represented by low expression of Ki-67 and increasing apoptosis. Photothermal therapy (PTT) can effectively stimulate immune response by increasing IL-6 and TNF-α. Notably, the treatment did not elicit any indications of toxicity. This injectable hydrogel holds significant promise as a multifaceted therapeutic agent that integrates photothermal and chemotherapeutic modalities.

Recent advances on chitosan/hyaluronic acid-based stimuli-responsive hydrogels and composites for cancer treatment: A comprehensive review

Cancer, as leading cause of death, has a high rate of mortality worldwide. Although there is a wide variety of conventional approaches for the treatment of cancer (such as surgery and chemotherapy), they have considerable drawbacks in terms of practicality, treatment efficiency, and cost-effectiveness. Therefore, there is a fundamental requirement for the development of safe and efficient treatment modalities based on breakthrough technologies to suppress cancer. Chitosan (CS) and hyaluronic acid (HA) polysaccharides, as FDA-approved biomaterials for some biomedical applications, are potential biopolymers for the efficient treatment of cancer. CS and HA have high biocompatibility, bioavailability, biodegradability, and immunomodulatory function which guarantee their safety and non-toxicity. CS-/HA-based hydrogels (HGs)/composites stand out for their potential anticancer function, versatile preparation and modification, ease of administration, controlled/sustained drug release, and active and passive drug internalization into target cells which is crucial for efficient treatment of cancer compared with conventional treatment approaches. These HGs/composites can respond to external (magnetic, ultrasound, light, and thermal) and internal (pH, enzyme, redox, and ROS) stimuli as well which further paves the way to their manipulation, targeted drug delivery, practicality, and efficient treatment. The above-mentioned properties of CS-/HA-based HGs/composites are unique and practical in cancer treatment which can ignore the deficiencies of conventional approaches. The present manuscript comprehensively highlights the advances in the practical application of stimuli-responsive HGs/composites based on CS/HA polysaccharides.

Chitosan-based nanosystems for cancer diagnosis and therapy: Stimuli-responsive, immune response, and clinical studies

Cancer, a global health challenge of utmost severity, necessitates innovative approaches beyond conventional treatments (e.g., surgery, chemotherapy, and radiation therapy). Unfortunately, these approaches frequently fail to achieve comprehensive cancer control, characterized by inefficacy, non-specific drug distribution, and the emergence of adverse side effects. Nanoscale systems based on natural polymers like chitosan have garnered significant attention as promising platforms for cancer diagnosis and therapy owing to chitosan's inherent biocompatibility, biodegradability, nontoxicity, and ease of functionalization. Herein, recent advancements pertaining to the applications of chitosan nanoparticles in cancer imaging and drug/gene delivery are deliberated. The readers are introduced to conventional non-stimuli-responsive and stimuli-responsive chitosan-based nanoplatforms. External triggers like light, heat, and ultrasound and internal stimuli such as pH and redox gradients are highlighted. The utilization of chitosan nanomaterials as contrast agents or scaffolds for multimodal imaging techniques e.g., magnetic resonance, fluorescence, and nuclear imaging is represented. Key applications in targeted chemotherapy, combination therapy, photothermal therapy, and nucleic acid delivery using chitosan nanoformulations are explored for cancer treatment. The immunomodulatory effects of chitosan and its role in impacting the tumor microenvironment are analyzed. Finally, challenges, prospects, and future outlooks regarding the use of chitosan-based nanosystems are discussed.

A Remarkable Impact of pH on the Thermo-Responsive Properties of Alginate-Based Composite Hydrogels Incorporating P2VP-PEO Micellar Nanoparticles

A heterograft copolymer with an alginate backbone, hetero-grafted by polymer pendant chains displaying different lower critical solution temperatures (LCSTs), combined with a pH-responsive poly(2-vinyl pyridine)-b-poly(ethylene oxide) (P2VP-b-PEO) diblock copolymer forming micellar nanoparticles, was investigated in aqueous media at various pHs. Due to its thermo-responsive side chains, the copolymer forms hydrogels with a thermo-induced sol-gel transition, above a critical temperature, Tgel (thermo-thickening). However, by lowering the pH of the medium in an acidic regime, a remarkable increase in the elasticity of the formulation was observed. This effect was more pronounced in low temperatures (below Tgel), suggesting secondary physical crosslinking, which induces significant changes in the hydrogel thermo-responsiveness, transforming the sol-gel transition to soft gel-strong gel. Moreover, the onset of thermo-thickening shifted to lower temperatures followed by the broadening of the transition zone, implying intermolecular interactions between the uncharged alginate backbone with the PNIPAM side chains, likely through H-bonding. The shear-thinning behavior of the soft gel in low temperatures provides injectability, which allows potential applications for 3D printing. Furthermore, the heterograft copolymer/nanoparticles composite hydrogel, encapsulating a model hydrophobic drug in the hydrophobic cores of the nanoparticles, was evaluated as a pH-responsive drug delivery system. The presented tunable drug delivery system might be useful for biomedical potential applications.