Mesoporous Silica Nanoparticles for Drug Delivery: Current Insights

Abstract

This manuscript reviews the recent progress on mesoporous silica nanoparticles as drug delivery systems. Their intrinsic structural, textural and chemical features permit to design versatile multifunctional nanosystems with the capability to target the diseased tissue and release the cargo on demand upon exposition to internal or external stimuli. The degradation rate of these nanocarriers in diverse physiological fluids is overviewed obeying their significance for their potential translation towards clinical applications. To conclude, the balance between the benefits and downsides of this revolutionary nanotechnological tool is also discussed.

Keywords: benefits and downsides; biosafety; clinical translation; in vitro degradation; mesoporous silica nanoparticles; multifunctional nanosystem; selective targeting; stimuli-responsive drug delivery.

Figure 1

Number of publications per year indexed in the ISI Web of Science on the topic of “mesoporous” and “silica” and “drug” and “delivery” up to 1st November 2017.

Figure 2

(Left) Schematic depiction of active targeting possibilities on MSNs; (Right) Dual targeting strategy to target both cell membrane of tumor cells and mitochondria by asymmetrically functionalized nanoparticles (J-MSNs).

Figure 3

Schematic representation of internal or external stimuli-responsive drug delivery from MSNs.

Figure 4

Schematic illustration of representative internal stimuli-responsive drug delivery MSNs: pH-responsive nanosystem based on polymer coated-MSNs; redox potential-responsive based on MSNs functionalized with disulfide bonds and capped with inorganic nanoparticles; and enzyme-responsive based on MSNs coated with a degradable polymer, from left to right.

Figure 5

Schematic depiction of three representative external stimuli-responsive drug delivery from MSNs via alternating magnetic fields (AM Field), ultrasounds (US) and visible (Vis) light (from left to right).

Figure 6

Representative illustration showing the in vitro degradation process in PBS for MSNs. TEM images before and after 8 and 12 days of in vitro assay are shown. The cartoons display the degradation process at the meso and atomic scales.

Figure 7

Main factors that drive the degradation of MSNs in physiological environment. TEM images of MSNs before and after being soaked in PBS under physiological conditions reveal the permanence of the structural and morphological characteristics after 8 days of in vitro test.