A Mesoporous Silica Nanosphere-Based Carrier System with Chemically Removable CdS Nanoparticle Caps for Stimuli-Responsive Controlled Release of Neurotransmitters and Drug Molecules

TLDR

The MSN system encapsulates drugs and neurotransmitters within its porous framework by capping channel openings with size‑defined CdS nanoparticles, preventing leaching. The authors aim to develop this MSN platform as a site‑selective, controlled‑release nanodevice for future therapeutic applications. They synthesized an MCM‑41 mesoporous silica nanosphere capped with surface‑derivatized CdS nanocrystals and examined its stimuli‑responsive release of vancomycin and ATP triggered by disulfide‑bond reducing agents such as DTT and ME. In vitro studies demonstrated that the MSN system is biocompatible and efficiently delivers cargo to astrocytes.

Abstract

An MCM-41 type mesoporous silica nanosphere-based (MSN) controlled-release delivery system has been synthesized and characterized using surface-derivatized cadmium sulfide (CdS) nanocrystals as chemically removable caps to encapsulate several pharmaceutical drug molecules and neurotransmitters inside the organically functionalized MSN mesoporous framework. We studied the stimuli-responsive release profiles of vancomycin- and adenosine triphosphate (ATP)-loaded MSN delivery systems by using disulfide bond-reducing molecules, such as dithiothreitol (DTT) and mercaptoethanol (ME), as release triggers. The biocompatibility and delivery efficiency of the MSN system with neuroglial cells (astrocytes) in vitro were demonstrated. In contrast to many current delivery systems, the molecules of interest were encapsulated inside the porous framework of the MSN not by adsorption or sol−gel types of entrapment but by capping the openings of the mesoporous channels with size-defined CdS nanoparticles to physically block the drugs/neurotransmitters of certain sizes from leaching out. We envision that this new MSN system could play a significant role in developing new generations of site-selective, controlled-release delivery nanodevices.