Fluorescent pH-Sensing Organic/Inorganic Hybrid Mesoporous Silica Nanoparticles with Tunable Redox-Responsive Release Capability

Abstract

We report on the fabrication of fluorescent pH-sensing organic/inorganic hybrid mesoporous silica nanoparticles (MSN) capable of tunable redox-responsive release of embedded guest molecules. The reversible addition-fragmentation chain transfer (RAFT) copolymerization of N-(acryloxy)succinimide (NAS), oligo(ethylene glycol) monomethyl ether methacrylate (OEGMA), and 1,8-naphthalimide-based pH-sensing monomer (NaphMA) at the surface of MSN led to fluorescent organic/inorganic hybrid MSN. The obtained hybrid MSN exhibits excellent water dispersibility and acts as sensitive fluorescent pH probes in the range pH 4-8 due to the presence of NaphMA moieties. After loading with rhodamine B (RhB) as a model drug molecule, P(NAS-co-OEGMA-co- NaphMA) brushes at the surface of hybrid MSN were cross-linked with cystamine to block nanopore entrances for the effective retention of guest molecules. Taking advantage of disulfide-containing cross-linkers, the release rate of RhB can be easily adjusted by adding varying concentrations of dithiothreitol (DTT), which can cleave the disulfide linkage to open blocked nanopores. The increase of DTT concentration from 0 to 20 mM led to 20-30 times enhancement of RhB release rate. The reported multifunctional hybrid MSN augurs well for applications in controlled-release nanocarriers, cell and tissue imaging, and clinical diagnosis.

Polyaspartic acid-anchored mesoporous silica nanoparticles for pH-responsive doxorubicin release

“…[24][25][26][27][28][29] The on-demand release behavior is generally regulated through the on/off of mesopores by anchoring different gatekeepers on their outlets. [30][31][32][33][34][35][36][37][38][39][40] However, the complexity of cancer malignancy still demands more efforts from researchers to resolve this severe current dilemma. Herein, we have designed doxorubicin-loaded polyaspartic acid-anchored MCM-41-type mesoporous silica nanoparticles (symbolized as DOX@P-MSNs) that demonstrate pHresponsive in vitro and intracellular drug release (Scheme 1).…”

Smart Nanocontainers: Preparation, Loading/Release Processes and Applications

“…For the release process, the active agents could be released from nanocontainers by external or internal stimuli, which referred to the chemical/physical/biochemical changes within or surrounding of the nanocontainer. For instance, various controlled release methodologies of active agents have been reported, such as desorption controlled release [73], pH-controlled release [1,34,70], temperature-responsive control [22], ion-exchange control [74,75], redox-responsive control of release [76,77], light-responsive controlled-release [78,79] and release under mechanical rapture [80,81].…”

Nanomedicine as an emerging approach against intracellular pathogens

“…75 Nanoparticles have been fabricated using a variety of materials, including poly(lactide-co-glycolide) (PLGA); [76][77][78][79][80][81] [98][99][100][101] PLGA has been approved by the Food and Drug Administration for several biomedical applications, including surgical sutures, implants, and prosthetic devices. 78 PLGA micro-or nanoparticles have also been used for a variety of drug delivery applications.…”

“…The effects of long-term nanoparticle accumulation are unknown, so in many cases it may be better to use a material that is fully biodegradable. Silica-based compounds are another option, as the biodegradation of silica avoids tissue accumulation concerns, 98 and it has been demonstrated that a variety of agents have been successfully incorporated into silica-based nanoparticles [99][100][101] for drug delivery applications. Although each of these materials offers its own set of characteristics and biocompatible properties, some materials may be more suited to certain applications than others.…”