Core@shell structured ceria@mesoporous silica nanoantibiotics restrain bacterial growth in vitro and in vivo

Mesoporous silica shell in a core@shell nanocomposite design enables antibacterial action with multiple modes of action

“…However, alteration in the trend could be due to instability of Con A as a result of thermal denaturation in the physiological environment (37 • C, pH 7.4, 0.15 M NaCl) and its interaction with charged molecules or surfaces [57]. In a previous study, a similar chelating effect by chitosan as the outermost coating layer of a core-shell structure was also observed around the same time point of 8 h; this was attributed to the properties of chitosan, which can adsorb trace metals and induce complexation of Ce [22].…”

“…The CeO 2 NPs were synthesized by two-stage non-isothermal precipitation employing a modified protocol [22]. In detail, 50 ml of 0.2 M Ce(NO 3 ) 3 solution was prepared by dissolving Ce(NO 3 ) 3 salt in distilled water at 70 • C followed by the dropwise addition of 25 ml of 3 M ammonium hydroxide solution.…”

“…For this purpose, CeO 2 NPs were dispersed in ultrapure Milli-Q water at a concentration of 1 mg ml −1 and dispersed by ultrasonication. Thereafter, a mixture of 4.3 ml of ultrapure water, 2.9 ml of absolute ethanol and 40 µl of ammonium hydroxide was pipetted into the CeO 2 solution during sonication to maintain nanoparticle dispersity [22].40 mg of CTAB, as the structure-directing agent, 660 µl of ultrapure water and 300 µl of absolute ethanol mixture were pipetted dropwise into the mixture. In the final step, 80 µl of TEOS, as the silica source, was added to the mixture and reaction was allowed to proceed overnight with stirring at room temperature.…”

“…It is known that Me/MeOx NPs tend to sediment or aggregate, which hinders their bioavailability [18][19][20] and is also inversely correlated with antibacterial activity due to the consequent decrease in surface area to volume ratio [21]. In order to overcome these disadvantages of Me/MeOx NPs the provision of a shell layer to act as a dispersing layer could be beneficial in antibacterial applications [22]. One study investigated the coating of cerium oxide nanoparticles (ceria, CeO 2 NPs) with an inorganic shell layer of porous silica to enhance the antibacterial activity [22].…”

“…In order to overcome these disadvantages of Me/MeOx NPs the provision of a shell layer to act as a dispersing layer could be beneficial in antibacterial applications [22]. One study investigated the coating of cerium oxide nanoparticles (ceria, CeO 2 NPs) with an inorganic shell layer of porous silica to enhance the antibacterial activity [22]. However, in that study the role of the porous silica shell in enabling synergistic/combinatory antibacterial activity and the mode of antibacterial action were not investigated in detail.…”