Mesoporous silica nanoparticles functionalised with a photoactive ruthenium(ii) complex: exploring the formulation of a metal-based photodynamic therapy photosensitiser

Abstract

A series of nanomaterials based on mesoporous silica have been synthesised and functionalised with a photoactive polypyridyl ruthenium(ii) complex, namely [Ru(bipy)2-dppz-7-hydroxymethyl][PF6]2 (bipy = 2,2'-bipyridine, dppz = dipyrido[3,2-a:2',3'-c]phenazine), by various methods. The functionalisation reactions were based on the covalent binding to different ligands attached to the pores of the mesoporous nanoparticles and a simple physisorption using polyamino-functionalised mesoporous silica nanoparticles. The resulting nanostructured systems have been characterised by XRD, XRF, BET, SEM and TEM, observing the incorporation of the metallodrug onto the nanostructured silica in a different way depending on the synthetic method used in the loading reactions. In our studies, we have also observed that functionalisation with the metallodrug causes changes in the structural and textural features of the materials. The phototherapeutic activity of the ruthenium-functionalised materials in HeLa cervical cancer cells has been tested and the preliminary results are presented herein.

Multifunctional Silica-Based Nanoparticles with Controlled Release of Organotin Metallodrug for Targeted Theranosis of Breast Cancer

“…In this sense, nanomaterials can act as suitable vectors for metallodrug delivery by (i) protecting the active species from degradation, (ii) enhancing their therapeutic activity [26], (iii) increasing drug bioavailability and specificity, or (iv) increasing the solubility [23,[27][28][29][30]. Because of its synthetic flexibility and biocompatibility, mesoporous silica-based nanostructured materials (MSN) represent one of the most used nanovectors in biomedicine, with special importance in metallodrug-based drug delivery systems [23,[31][32][33][34][35][36][37][38]. Consequently, the MSNs have stood out in different biomedical fields such as molecular imaging (fluorescence and magnetic resonance imaging) and drug delivery [39][40][41][42][43][44][45].…”

Synthesis, Characterization, and Biological Evaluation of Red-Absorbing Fe(II) Polypyridine Complexes

“…Therefore, to assess the potential of our PSs, we have investigated their ability to produce 1 O 2 upon light irradiation. To quantitatively evaluate this, we used two methods: (1) a direct method by measurement of the phosphorescence of 1 and (2) an indirect method by measurement of the absorption changes of a reporter molecule [23,70]. The results (Table 1) show that complexes 4-6 are poorly producing 1 O 2 with quantum yields from 2% to 4% in aerated CH 3 CN and <1% in aerated PBS at the detection limit of our used system.…”

Nano-Based Systems and Biomacromolecules as Carriers for Metallodrugs in Anticancer Therapy

“…The advantages of silica carriers include chemical stability, ease of surface modification with different functional groups for subsequent drug conjugation, as well as a tunable pore diameter [95]. Gomes-Ruiz's group employed mesoporous silica nanoparticles as carriers for tin, titanium, and ruthenium complexes [34,[96][97][98][99][100][101][102][103]. Interestingly, they observed that the entire nanostructure of mesoporous silica-drug conjugate was involved in triggering cancer cell apoptosis, and only a small release of the encapsulated metallodrug was contributing to cytotoxic effects.…”