Label-Free Luminescent Mesoporous Silica Nanoparticles for Imaging and Drug Delivery

Abstract

We report herein a straightforward and label-free approach to prepare luminescent mesoporous silica nanoparticles. We found that calcination at 400 °C can grant mesoporous organosilica nanoparticles with strong fluorescence of great photo- and chemical stability. The luminescence is found to originate from the carbon dots generated from the calcination, rather than the defects in the silica matrix as was believed previously. The calcination does not impact the particles' abilities to load drugs and conjugate to biomolecules. In a proof-of-concept study, we demonstrated that doxorubicin (Dox) can be efficiently encapsulated into these fluorescent mesoporous silica nanoparticles. After coupled to c(RGDyK), the nanoconjugates can efficiently home to tumors through interactions with integrin αvβ3 overexpressed on the tumor vasculature. This calcination-induced luminescence is expected to find wide applications in silica-based drug delivery, nanoparticle coating, and immunofluorescence imaging.

Multifunctional calcium phosphate nanoparticles for combining near-infrared fluorescence imaging and photodynamic therapy

“…Among them, RGD peptides are particularly suitable for enhancing intratumoral probe enrichment. RGD peptides specifically bind to a v b 3 integrins on the activated endothelium of angiogenic blood vessels, they can easily be conjugated to nanoparticles and they are cheaper than antibodies [17][18][19][20].…”

Gd‐Encapsulated Carbonaceous Dots with Efficient Renal Clearance for Magnetic Resonance Imaging

“…This correlates with previous observations that calcination at low pressure typically yields amorphous structures. [9] Elemental mapping revealed that Gd was distributed evenly within the carbon particles with no signs of crystallization (Figure 1c, S1). This was also confirmed by scanning transmission electron microscopy (STEM) on individual C-dot particles (Figure 1d), revealing that Gd was well encased within the carbon shell (Figure 1e).…”

“…The spectrum resembles those published previously of pure C-dots. [9b, 11b, 12] The Gd@C-dots are also highly fluorescent, and can be excited by light of a wide range of wavelengths to emit strong photoluminescence (Figure 2a). Such wavelength-dependent fluorescence is also similar to conventional C-dots.…”

“…Such wavelength-dependent fluorescence is also similar to conventional C-dots. [9a, 11a] Impressively, there was almost no drop of photoluminescence intensity of Gd@C-dots even after 24 hours of continuous UV illumination (Figure 2b). This photostability is vastly superior to organic dye molecules, and even better than CdSe/ZnS quantum dots, [13] both of which were completely bleached within hours of UV exposure (Figure 2c).…”

Redefining the role(s) of endothelial αvβ3-integrin in angiogenesis

“…Several simple strategies, such as conjugating RGD-targeting peptides to traditional chemotherapeutics (e.g. and they can be surfacecoated in integrin targeting molecules, antibodies or RGD peptides [38]. These approaches provide increased chemotherapeutic dose at the tumour as well as increased duration of effect compared with non-RGD targeted controls [35,36].…”