Silica Nanocapsules of Fluorescent Conjugated Polymers and Superparamagnetic Nanocrystals for Dual‐Mode Cellular Imaging

Abstract

We describe here a facile and benign synthetic strategy to integrate the fluorescent behavior of conjugated polymers and superparamagnetic properties of iron oxide nanocrystals into silica nanocapsules, forming a new type of bifunctional magnetic fluorescent silica nanocapsule (BMFSN). The resultant BMFSNs are uniform, colloidally stable in aqueous medium, and exhibit the desired dual functionality of fluorescence and superparamagnetism in a single entity. Four conjugated polymers with different emissions were used to demonstrate the versatility of employing this class of fluorescent materials for the preparation of BMFSNs. The applicability of BMFSNs in cellular imaging was studied by incubating them with human liver cancer cells, the result of which demonstrated that the cells could be visualized by dual-mode fluorescence and magnetic resonance imaging. Furthermore, the superparamagnetic behavior of the BMFSNs was exploited for in vitro magnetic-guided delivery of the nanocapsules into the cancer cells, thereby highlighting their potential for targeting biomedical applications.

Nonporous silica nanoparticles for nanomedicine application

“…Silica NPs encapsulating MRI contrast agents, including paramagnetic complexes (Ga 3+ - or Mn 2+ -based chelates) [186–188] and superparamagnetic iron oxide NPs [189–195], have been extensively studied. For example, a Ga 3+ -containing silica NP reported by Ji et al [195] and iron oxide NP–bearing silica NPs reported by Cho et al [191] have been used for in vivo MRI.…”

Fluorescent Nanocomposites

“…As an example, bifunctional magnetic fl uorescent silica nanocapsules were synthesized by employing conjugated polymers as the fl uorescent emitters and iron oxide nanocrystals as the magnetic constituent, both of which were encapsulated inside the nanocore of a thin silica shell (Fig. 6.15 ) (Tan et al 2011 ).…”

Luminescent Silica Nanoparticles for Cancer Diagnosis

“…The super-paramagnetic behavior of these particles was further exploited for their magnetic guidance into cancer cells. 55 A similar dual modal nanoprobe, combining optical and MR imaging was produced as a 16 nm-silica carbonate nanoparticle simultaneously doped with a rare earth ion (Terbius) and Gadolinium. In vitro , these nanoparticles were efficiently delivered to different cancer cell lines, e.g.…”

“…This work demonstrates that C dots combine the benefits of PET (tissue penetration, quantification) with those of IR/NIR optical imaging (sensitivity/contrast, multispectral capabilities) for the development of surgically-based or interventionally-driven therapies. 55,101 Discussions have begun with the FDA to start clinical trials using carbon nanotubes to improve colorectal cancer imaging. This imaging agent and associated is being developed by the Center for Cancer Nanotechnology Excellence Focused on Therapy Response (Stanford University CCNE).…”