Sol-gel synthesis of magnesium oxide nanoparticles and their evaluation as a therapeutic agent for the treatment of osteoarthritis.

Aim: We synthesized MgO NPs via sol-gel reaction and investigated them as carriers to deliver Mg2+ to the affected joint for osteoarthritis (OA).Materials & methods: The physicochemical properties of samples were characterized by transmission electron microscope (TEM), dynamic light scattering (DLS) and x-ray diffraction (XRD). The release of Mg2+ was monitored by ICP-MS. The potential cytotoxicity was evaluated using MTT assay. The efficacy and biosafety were evaluated in a rabbit OA model.Results: MgO NPs can prolong the Mg2+ release time from 0.5 h to 12 h. No significant cytotoxicity was observed when concentrations below 250 µg/ml. Intra-articular samples could effectively alleviate the degeneration and destruction of the cartilage.Conclusion: this study demonstrates the potential of MgO NPs as a safe and effective treatment of OA. Simultaneously, the size of the particles may play a significant role in influencing the therapeutic outcome.

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Stabilized Cell Membrane-Derived Vesicles by Lipid Anchoring for Enhanced Drug Delivery.

A cell membrane-derived vesicle (MV) that has cell-mimicking features with characteristic functionalities holds vast appeal for biomimetic nanomedicine and drug delivery but suffers from a major limitation of innate fragility and poor stability. Herein, we report a lipid-anchoring strategy for stabilizing MV for enhanced drug delivery. An array of amphiphilic mono-acyl phosphatidylcholines (MPCs) with specific hydrophobic moieties are synthesized and readily engineered on MV based on their commendable aqueous solubility and efficient membrane insertability. Incorporation of MPCs containing rigid ring structures in the hydrophobic segment demonstrates the potency of stabilizing MV by the combined ordering and condensing effects. The optimized MPC-stabilized MV exhibits prolonged circulation in the bloodstream, elevated accumulation within a tumor, and enhanced therapeutic effects of chemotherapeutic and photothermal drugs. Moreover, doxorubicin-loaded MV, engineered with mono-all-trans retinoyl phosphatidylcholine as an MV stabilizer and a therapeutic prodrug, potently suppresses growth and metastasis of high-stemness tumors.

Modulation of Dendritic Cell Function via Nanoparticle-Induced Cytosolic Calcium Changes.

Calcium nanoparticles have been investigated for applications, such as drug and gene delivery. Additionally, Ca2+ serves as a crucial second messenger in the activation of immune cells. However, few studies have systematically studied the effects of calcium nanoparticles on the calcium levels and functions within immune cells. In this study, we explore the potential of calcium nanoparticles as a vehicle to deliver calcium into the cytosol of dendritic cells (DCs) and influence their functions. We synthesized calcium hydroxide nanoparticles, coated them with a layer of silica to prevent rapid degradation, and further conjugated them with anti-CD205 antibodies to achieve targeted delivery to DCs. Our results indicate that these nanoparticles can efficiently enter DCs and release calcium ions in a controlled manner. This elevation in cytosolic calcium activates both the NFAT and NF-κB pathways, in turn promoting the expression of costimulatory molecules, antigen-presenting molecules, and pro-inflammatory cytokines. In mouse tumor models, the calcium nanoparticles enhanced the antitumor immune response and augmented the efficacy of both radiotherapy and chemotherapy without introducing additional toxicity. Our study introduces a safe nanoparticle immunomodulator with potential widespread applications in cancer therapy.

Self-regulated hirudin delivery for anticoagulant therapy.

Pathological coagulation, a disorder of blood clotting regulation, induces a number of cardiovascular diseases. A safe and efficient system for the delivery of anticoagulants to mimic the physiological negative feedback mechanism by responding to the coagulation signal changes holds the promise and potential for anticoagulant therapy. Here, we exploit a "closed-loop" controlled release strategy for the delivery of recombinant hirudin, an anticoagulant agent that uses a self-regulated nanoscale polymeric gel. The cross-linked nanogel network increases the stability and bioavailability of hirudin and reduces its clearance in vivo. Equipped with the clot-targeted ligand, the engineered nanogels promote the accumulation of hirudin in the fibrous clots and adaptively release the encapsulated hirudin upon the thrombin variation during the pathological proceeding of thrombus for potentiating anticoagulant activity and alleviating adverse effects. We show that this formulation efficiently prevents and inhibits the clot formation on the mouse models of pulmonary embolism and thrombosis.