Biodegradability of Disulfide-Organosilica Nanoparticles Evaluated by Soft X-ray Photoelectron Spectroscopy: Cancer Therapy Implications

Abstract

Two kinds of organosilica nanoparticles (NPs) that were fabricated from thiol-containing precursors, (3-mercaptopropyl)­trimethoxysilane (MPMS) and (3-mercaptopropyl)­methyldimethoxysilane (MPDMS), are potential delivery vehicles of anticancer drugs. MPMS can form three siloxane bonds, but MPDMS forms two siloxane bonds as the maximum limit. Hence, disulfide bonds can be involved in the three-dimensional morphology of MPDMS NPs. In addition, NPs containing disulfide bonds are potentially degraded by a reduced form of glutathione (GSH). To examine reactions between the organosilica NPs and GSH, the NPs were incubated in 10 mM GSH aqueous solution at 37 °C for 7 d and the products were analyzed using field-emission scanning electron microscopy (FE-SEM), Raman spectroscopy, and soft X-ray photoelectron spectroscopy (XPS). The Raman spectra showed the presence of disulfide bonds in the MPDMS NPs and the absence of disulfide bonds in MPMS NPs. The results of XPS measurements suggested that the disulfide bonds in the outer layer of MPDMS NPs were reduced to thiol groups. FE-SEM observations of MPDMS NPs detected changes in NP morphology after the GSH incubation. These results support the idea that MPDMS NPs contain disulfide bonds and are degradable by GSH. Therefore, MPDMS NPs possess a biodegradable feature that is advantageous for clinical translation, that is, nanomedicine.

Synthesis of an amphiphilic spiro‐multiblock copolymer via thiol‐ene click chemistry

“…Although there was some noise, no peak was observed in the energy region of SS. In addition, SC S 2p 1/2 and SC S 2p 3/2 peaks were observed in the S 2p energy region from 165.5 to 164.8 eV . Likewise, polyrings showed peaks in the same region due to the presence of SC bonds.…”

Recent Development to Explore the Use of Biodegradable Periodic Mesoporous Organosilica (BPMO) Nanomaterials for Cancer Therapy

“…Later, Mekaru et al evaluated the biodegradability of disulfide-organosilica nanoparticles by soft x-ray photoelectron spectroscopy for cancer therapy implications [60]. They used two kinds of organosilica nanoparticles, MPMS and MPDMS, that were fabricated similarly to those described by Doura et al [59].…”

Trends in Degradable Mesoporous Organosilica-Based Nanomaterials for Controlling Drug Delivery: A Mini Review

“…It is notorious that there is a difference in the GSH concentration between tumor tissues (2–10 mM) and normal tissues (below 0.002 mM) [ 27 ]. In this regard, Mekaru H. and co-workers used uniquely thiol-containing precursors in the preparation of degradable silica-based nanoparticles [ 28 ]. Here, (3-mercaptopropyl) trimethoxysilane (MPMS) or (3-mercaptopropyl) methyldimethoxysilane (MPDMS) were selected to form three or two siloxane bonds inside the silica support, respectively.…”