Gold Nanostars Coated with Mesoporous Silica Are Effective and Nontoxic Photothermal Agents Capable of Gate Keeping and Laser-Induced Drug Release

Abstract

Herein, a novel drug photorelease system based on gold nanostars (AuNSts), coated with a mesoporous silica shell and capped with paraffin as thermosensitive molecular gate, is reported. Direct measurements of the surface temperature of a single gold nanostar irradiated using a tightly focused laser beam are performed via a heat-sensitive biological matrix. The surface temperature of a AuNSt increases by hundreds of degrees (°C) even at low laser powers. AuNSts coated with a mesoporous silica shell using a surfactant-templated synthesis are used as chemotherapeutic nanocarriers. Synthetic parameters are optimized to avoid AuNSt reshaping, and thus to obtain nanoparticles with suitable and stable plasmonic properties for near-infrared (NIR) laser-triggered cargo delivery. The mesoporous silica-coated nanostars are loaded with doxorubicin (Dox) and coated with octadecyltrimethoxysilane and the paraffin heneicosane. The paraffin molecules formed a hydrophobic layer that blocks the pores, impeding the release of the cargo. This hybrid nanosystem exhibits a well-defined photodelivery profile using NIR radiation, even at low power density, whereas the nonirradiated sample shows a negligible payload release. Dox-loaded nanoparticles displayed no cytotoxicity toward HeLa cells, until they are irradiated with 808 nm laser, provoking paraffin melting and drug release. Hence, these novel, functional, and biocompatible nanoparticles display adequate plasmonic properties for NIR-triggered drug photorelease applications.

Near-infrared photoresponsive drug delivery nanosystems for cancer photo-chemotherapy

“…Mesoporous silica nanoparticles (MSNs) have been used to develop photothermal responsive DDSs for cancer therapy [ 68 – 70 ]. For example, Kim and Yong et al constructed a mesoporous silica coated silver–gold hollow nanoplatform to precisely regulate the release of 5-fluorouracil (anticancer drug) for prostate cancer therapy and photothermal therapy [ 70 ].…”

Mesoporous Silica Platforms with Potential Applications in Release and Adsorption of Active Agents

“…Shao et al have comparatively studied the effects of varying the shape and aspect ratio of magnetic MSN on the endocytosis, biocompatibility, and biodistribution, which could provide the means for considerably improving the efficiency and safety of MSN systems in cancer theranostics. Their silica-coated superparamagnetic nanoparticles conjugated with fluorescent, as well as targeting moieties, showed a higher cellular internalization of rod-like nanoparticles compared with sphere-like nanoparticles [127]. Similarly, the effect of shape was the subject of Zhang's study, who synthesized two types of MSNs in order to investigate an optimal incorporation of indomethacin within the mesopores.…”

Janus Gold Nanostars–Mesoporous Silica Nanoparticles for NIR‐Light‐Triggered Drug Delivery

“…One of the most studied applications of these gated systems is their use as nanodevices for controlled drug delivery . Among different stimuli, nanodevices for controlled release in response to light irradiation are particularly appealing since cargo delivery can be triggered at will by choosing the area and time of irradiation .…”

“…[6] One of the most studied applications of these gated systems is their use as nanodevicesf or controlled drugd elivery. [7][8][9][10][11][12] Amongd ifferent stimuli, nanodevicesf or controlled releasei n responset ol ight irradiation are particularly appealing since cargo delivery can be triggered at will by choosing the area and time of irradiation. [13,14] Moreover,t he design of nanodevices able to release an entrapped drug by using near infrared (NIR)l ight have remarkable interestd ue to the high penetrationo fN IR radiation and minimal damage to tissues.…”