Tailoring the biodegradability of porous silicon nanoparticles

Abstract

Porous silicon nanoparticles (PSiNPs) are attractive carriers for targeted drug delivery in nanomedicine. For in vivo applications, the biodegradation property of PSiNPs provides a pathway for their safe clearance from the body. Particles sizes of 80-120 nm are of particular interest as they are important for cellular applications, such as drug delivery for cancer therapy, because these nanoparticles can take advantage of the enhanced permeability and retention effect to deliver drug preferentially to tumors with leaky vasculature, yet large enough to avoid renal clearance. However, the biodegradability rate of such particles is often too fast, which limits particle half-life and potentially reduces their in vivo delivery efficiency. In this work, we focus on the degradation of nanoscale particles and study the effect of both thermal oxidation and silica coating on the stability of PSiNPs in phosphate buffered saline solution (a close mimic of a basic biological fluid). Using thermal oxidation, the half-life of PSiNPs can be varied from 10 min up to 3 h. Using silica coating, the half-life can be extended further to 8 h. The particles produced using both these techniques can be functionalized using standard silica surface chemistries developed for applications in drug delivery.

Guiding Principles in The Design of Ligand-Targeted Nanomedicines

“…While receptor-mediated uptake of natural ligands may occur via multiple pathways [116,117], the more common of these pathways can only accommodate particles of diameters <120 nm [118]. Ligand-derivatized NPs larger than this must, therefore, enter cells via a phagocytic mechanism, which almost always deposits the internalized cargo into lysosomes.…”

Nanostructured porous Si-based nanoparticles for targeted drug delivery

“…PSi degradation rate is directly correlated with the particle’s size diameter and pore 93 . However, in the case of the particles with diameters around 100 nm presenting pores sizes between 5 and 20 nm, the stability of the particles does not strongly depend on the pore size 69 .…”

“…In this respect, Hon et al developed two thermal oxidation processes: (1) peroxidation using rapid thermal processing (RTP) and (2) postoxidation using hot aqueous baths 93 . To measure the degradation rate of the different types of PSiNPs, they digested and analyzed the concentration of dissolved Si in a phosphate buffer saline solution at a constant temperature of 37°C.…”

“…In another study, the effect of the silica-coating on the half-life of the particles was also evaluated 93 . Instead of oxidizing the Si particles, a layer of silica was chemically grown over a hydroxyl PSi surface-terminated.…”

Altering the Biodegradation of Mesoporous Silica Nanoparticles by Means of Experimental Parameters and Surface Functionalization

“…These NPs degraded after only 40 minutes, but the degradation was slowed down up to 3 hours after thermal oxidation [15].…”