Biological Activity of Mesoporous Dendrimer-Coated Titanium Dioxide: Insight on the Role of the Surface–Interface Composition and the Framework Crystallinity

Abstract

Hitherto, the field of nanomedicine has been overwhelmingly dominated by the use of mesoporous organosilicas compared to their metal oxide congeners. Despite their remarkable reactivity, titanium oxide-based materials have been seldom evaluated and little knowledge has been gained with respect to their "structure-biological activity" relationship. Herein, a fruitful association of phosphorus dendrimers (both "ammonium-terminated" and "phosphonate-terminated") and titanium dioxide has been performed by means of the sol-gel process, resulting in mesoporous dendrimer-coated nanosized crystalline titanium dioxide. A similar organo-coating has been reproduced using single branch-mimicking dendrimers that allow isolation of an amorphous titanium dioxide. The impact of these materials on red blood cells was evaluated by studying cell hemolysis. Next, their cytotoxicity toward B14 Chinese fibroblasts and their antimicrobial activity were also investigated. Based on their variants (cationic versus anionic terminal groups and amorphous versus crystalline titanium dioxide phase), better understanding of the role of the surface-interface composition and the nature of the framework has been gained. No noticeable discrimination was observed for amorphous and crystalline material. In contrast, hemolysis and cytotoxicity were found to be sensitive to the nature of the interface composition, with the ammonium-terminated dendrimer-coated titanium dioxide being the most hemolytic and cytotoxic material. This surface-functionalization opens the door for creating a new synergistic machineries mechanism at the cellular level and seems promising for tailoring the biological activity of nanosized organic-inorganic hybrid materials.

From Nanobiotechnology, Positively Charged Biomimetic Dendrimers as Novel Antibacterial Agents: A Review

“…It can be observed that although a high number of studies have been reported on cationic peptide Ds, dendrimers such as PAMAM Ds and peptide Ds have been developed throughout the decade. On the contrary, other structures, such as ammonium-terminated Ds (AT-Ds), including AT phosphorous and carbosilane Ds [ 59 , 60 ], attracted the interest of scientists only after 2015. Other Ds, such as PPI Ds, after initial consideration, were neglected, while PEI-Ds and organometallic Ds (OM-Ds), were taken into consideration only marginally.…”

“…By performing a sol-gel process, the fruitful association of a fourth-generation phosphorus dendrimer, peripherally modified with quaternized ethylene diamine and titanium dioxide (TiO 2 ), was realized by Milowska et al (2015) together with other three ones [ 59 ]. The hybrid mesoporous dendrimer-coated TiO 2 obtained showed to be nanosized, in a crystalline and to possess a surface mimicking that one of PEI-Ds.…”

“…Cationic carbosilane Ds have shown their potential to be used as devices in several biomedical applications including as bactericides [ 59 ]. Both silicon containing hyperbranched polymers and Ds are interesting as organic-inorganic hybrid materials, due to the presence of C–Si bonds, that confer high stability and very low hydrophilicity, favorable to the processes of bio permeability [ 60 ].…”

Comparative study of the anchorage and the catalytic properties of nanoporous TiO2 films modified with ruthenium (II) and rhenium (I) carbonyl complexes

“…The photovoltaic cells based on titanium dioxide are wellknown for its high-efficiency in dye-sensitized solar cells since Grätzel and co-workers incorporated dinitrogenated ruthenium (II) complexes onto the TiO 2 surface [1][2][3]. TiO 2 surfaces as rutile or anatase-like forms have a skeleton of titanium and oxygen atoms spatially distributed [4,5] providing a high number of Ti-OH groups on the solid surface [6,7], which allows linking of organometallic compounds and organic chains for the preparation of hybrid materials [8][9][10]. On the other hand, the controlled manufacture of dye-sensitized TiO 2 structures at the nanometric scale allows either promote or suppress the recombination of electron and hole pairs upon UV-visible light excitation, conferring to TiO 2 -based materials an increasing interest within renewable energy and environment fields as well as in nanotechnology [1][2][3][4][5]8,9].…”

Dendrimer-Functionalized Laponite Nanodisks as a Platform for Anticancer Drug Delivery

“…Biocompatible poly(ethylene glycol) (PEG) can also be modified on dendrimers to decrease the cytotoxicity of dendrimers and improve their biodistribution behavior [ 26 , 27 ]. Since the combination of organic and inorganic nanohybrids has been demonstrated to have a synergistic performance [ 28 , 29 , 30 ], it is plausible to hypothesize that the modification of PAMAM dendrimers on the surface of LAP nanodisks would improve the performance of a LAP-based drug delivery system through providing additional drug loading capacity and endowing LAP nanodisks with active functional groups for targeting modification.…”