Two‐Photon‐Triggered Drug Delivery via Fluorescent Nanovalves

Abstract

the systems described so far require UV-Vis light which limits their applications. Two-Photon Excitation (TPE) in the near-infrared region is a promising alternative to UV-vis light due to the many advantages TPE provides such as three dimensional spatial resolution, lower scattering losses, and deeper penetration in tissues.[ 16 ] Very few TPE-triggered MSN-based drug delivery systems have been described in the literature, [ 17,18 ] and only two very recent examples were reported with cytotoxic drug delivery in cancer cells. The fi rst example is based on coumarin cleavage and needed very high material concentration (1 mg mL −1 ) in cells and long time of irradiation (1 h) to observe a cancer cell killing effect.[ 19 ] The second was described by us and concerned nanoimpellers reconfi gured for TPE.[ 20 ] The system was effi cient in inducing cancer cell death under TPE. In this communication, we report an alternative MSN-azobenzene-based system with a high specifi c surface area and pore volume for TPE-triggered drug delivery in cancer cells. Furthermore, two-photon fl uorescence imaging in vitro was also performed (see Scheme 1 ). First of all, a novel two-photon paracyclophane-based fl uorophore (CF) possessing a high two-photon absorption cross-section was designed and fully characterized. (see the Supporting Information). The maximum emission of the fl uorophore was 415 nm in THF, with a quantum yield of 68% suitable for FRET with azobenzene ( Figure 1 ).The silylated fl uorophore (CF) was co-condensed with tetraethoxysilane (TEOS) and cetyltrimethylammonium bromide (CTAB) in basic media to lead to the two-photon fl uorescent MSN (MCF NPs). Mono-triethoxysilylated azobenzene was then grafted on the surface of the nanoparticles (MCF-AZO NPs). Then, the cargo was loaded in the pores of the MCF-AZO NPs. The supramolecular complexation of β-cyclodextrin was performed in ice-cooled conditions, in order to cap the porous surface to lead to the nanovalve (MCF-AZO@βCD NPs). As a control MCM-41 type MSN NPs were functionalized with azobenzene (MSN-AZO NPs) and β-cyclodextrin MSN-AZO@βCD NPs using the same procedure.The characterizations of the MCF NPs after surfactant removal confi rmed the monodispersity and mesoporosity of Drug Delivery

Biodegradable Magnetic Silica@Iron Oxide Nanovectors with Ultra-Large Mesopores for High Protein Loading, Magnetothermal Release, and Delivery

“…[37] Silica NPs are slowly degraded in water by dissolution into biocompatible and bioadsorbed silicic acid products, [38] and silica NPs are renally excreted. [39][40][41] The unique properties of MSN and silica hybrid NPs have been implemented in catalysis, [37,42] separation, [43][44][45] bio-imaging, [33,[46][47][48] and in cargo delivery applications, [34][35][36][37][49][50][51] to name a few. Large-pore silica and silica hybrid NPs have also been designed for biomedical applications.…”

Light- and pH-activated intracellular drug release from polymeric mesoporous silica nanoparticles

“…With the superiority of remote control, low toxicity, non-invasion, light has been considered as a safe and specific trigger for nanomedicines. [7][8][9][10][11] The drug release process could be controlled by tuning the light wavelength or energy, and entrapped drugs could be released at the desired time and location. [12,13] Azobenzene presents a UV-induced trans-tocis isomerization property, and it has been widely exploited for drug release due to its photoswitchable host-guest interaction with α-cyclodextrin.…”

Protein-gold clusters-capped mesoporous silica nanoparticles for high drug loading, autonomous gemcitabine/doxorubicin co-delivery, and in-vivo tumor imaging

“…[26][27][28][29][30][31][32][33][34] MSN are biocompatible nanomaterials [35,36] and possess disctinctive characteristics such as their tunable porosity and particle size, versatile inner and outer surface chemistry, and capacity to transport and deliver various cargos make these scaffolds ideal drug delivery systems. [37,38] Both molecular and supramolecular nanomachines have been designed with MSN to precisely control the release of guest molecules from their nanopores upon various stimuli including pH, [39,40] one- [41,42] and two-photon irradiation, [43][44][45] enzymes [46,47] and redox processes. [48] Capping the pores of MSN was also carried out with inorganic particles, [49,50] dendrimers, [51] and covalently-attached proteins.…”