A novel combination of in situ-forming hydrogels of hyaluronic acid with gated mesoporous materials was developed to design depots for local sustained release of chemotherapeutics. The depot consists of a hyaluronic-based gel loaded with redox-responsive mesoporous silica nanoparticles loaded with safranin O or doxorubicin and capped with polyethylene glycol chains containing a disulfide bond. The nanoparticles are able to deliver the payload in the presence of the reducing agent, glutathione (GSH), that promotes the cleavage of the disulfide bonds and the consequent pore opening and cargo delivery. Release studies and cellular assays demonstrated that the depot can successfully liberate the nanoparticles to the media and, subsequently, that the nanoparticles are internalized into the cells where the high concentration of GSH induces cargo delivery. When the nanoparticles were loaded with doxorubicin, a significant reduction in cell viability was observed. Our research opens the way to the development of new depots that enhance the local controlled release of chemotherapeutics by combining the tunable properties of hyaluronic gels with a wide range of gated materials.

The main cause of subretinal neovascularisation in wet age-related macular degeneration (AMD) is an abnormal expression in the retinal pigment epithelium (RPE) of the vascular endothelial growth factor (VEGF). Current approaches for the treatment of AMD present considerable issues that could be overcome by encapsulating anti-VEGF drugs in suitable nanocarriers, thus providing better penetration, higher retention times, and sustained release. In this work, the ability of large pore mesoporous silica nanoparticles (LP-MSNs) to transport and protect nucleic acid molecules is exploited to develop an innovative LP-MSN-based nanosystem for the topical administration of anti-VEGF siRNA molecules to RPE cells. siRNA is loaded into LP-MSN mesopores, while the external surface of the nanodevices is functionalised with polyethylenimine (PEI) chains that allow the controlled release of siRNA and promote endosomal escape to facilitate cytosolic delivery of the cargo. The successful results obtained for VEGF silencing in ARPE-19 RPE cells demonstrate that the designed nanodevice is suitable as an siRNA transporter.

Glioblastoma multiforme (GBM) is a highly aggressive brain cancer associated with poor survival rates. We developed novel mesoporous silica nanoparticles (MSNs)-based nanocarriers for pH-responsive delivery of a therapeutic drug Paclitaxel (PTX) to GBM tumor cells. The pores of MSNs are loaded with PTX, which is retained by β-cyclodextrin (CD) moieties covalently linked to the pore entrances through a hydrazone linkage, which is cleavable in weakly acidic environment. Furthermore, we utilized a host-guest interaction between the adamantane and capping CD moieties to further functionalize the surface with a potential glioma-targeting oligopeptide chlorotoxin (CHX). In vitro studies in the U87 GBM cell line show decreased uptake, but increased toxicity of CHX-modified nanoparticles compared to CHX-free nanoparticles. The obtained results are promising toward development of advanced drug nanocarriers, which may target the overexpressed receptors in cancer tissues and utilize their weakly acidic environment for triggering the drug release, potentially leading to more efficient cancer treatments.

Nanoparticle–cell–nanoparticle communication by stigmergy was demonstrated using two capped nanodevices. The first community of nanoparticles (i.e.S(RA)_IFN) is loaded with 9-cis-retinoic acid and capped with interferon-γ, whereas the second community of nanoparticles (i.e.S(sulf)_PIC) is loaded with sulforhodamine B and capped with poly(I:C). The uptake of S(RA)_IFN by SK-BR-3 breast cancer cells enhanced the expression of TLR3 receptor facilitating the subsequent uptake of S(sulf)_PIC and cell killing.