Multifunctional silica nanoparticles for optical and magnetic resonance imaging

Abstract

The surface of spherical, nonporous silica nanoparticles (SiO2-NPs) was modified with gadolinium (Gd) complexes, fluorophores, and cell-penetrating peptides to achieve multifunctionality on a single particle. The Gd surface concentrations were 9–16 μmol/g resulting in nanomaterials with high local longitudinal and transversal relaxivities (~1×105 and ~5×105 /mm/s/NP, respectively). Rapid cellular uptake was observed in vitro; however, larger extracellular agglomerates were also formed. In vivo administration revealed a fast distribution throughout the body followed by a nearly complete disappearance of fluorescence in all organs except the lungs, liver, and spleen after 24 h. Such NPs have the potential to serve as efficient multimodal probes in molecular imaging.

Recent development of silica nanoparticles as delivery vectors for cancer imaging and therapy

“…100 The capability of these multifunctional nanomaterials in imaging provides high quality images for guiding therapeutic agents. 101 During and after the therapy, the images could be used for monitoring the effects of therapy. These properties may improve drug delivery efficacy and survival rates, and minimize side effects of drugs to normal tissues.…”

“…This multimodel imaging system can greatly increase the diagnosis accuracy and sensitivity. 101, 102 For example, Huang et al developed a multifunctional MSN that incubated fluorescence imaging, MRI and PET for tumor imaging and probe localization. 103 The multimodel therapy system contains the SiNPs that incubated different therapeutic strategies.…”

Recent advances in Gd-chelate based bimodal optical/MRI contrast agents

“…In view of the toxicity of anthracene, more studies concerning the biodistribution and anthracene leakage in vivo will be necessary in order to fully assess the potential of this system as a theranostic. [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][44][45][46][47][48][49][50][51] An expanded view of the structures marked with a star can be found in the ESI † (Fig. S3-S6) (see framed structures in Fig.…”

“…In order to overcome the inherent flexibility of these biopolymers, the polymers can be conjugated with a lipophilic chain, thus creating a polyamphiphilic molecule, adopting a more rigid core-shell conformation, with an inner lipophilic and outer hydrophilic composition. This strategy was used by Nam et al 40 (35) and Cho et al 41 (36) using a chitosan backbone and a hyaluronic acid backbone, respectively. In the case of the chitosan particle, the relaxivity was considerably less than that of free GdDOTA, which is presumably caused by an unfavourable location of the conjugated Gd 3+ complex in the lipophilic core, the hyaluronic acid conjugate on the other hand exhibited a r 1 of 19.8 mM À1 s À1 at 4.7 T, as the Gd 3+ conjugate was now present on the surface of the nanoparticle.…”

Simultaneous Enhancement of Intracellular Optical Imaging and Photothermal Therapeutic Response by Octaarginine-Modified Fluorescent Dye Doped Pd@Ag@SiO<SUB>2</SUB>(RITC) Multifunctional Nanoparticles

“…Fluorescent dye rhodamine B isothiocyanate (RITC) was covalently doped into the silica shell for fluorescent imaging (Pd@Ag@SiO 2 (RITC)). In order to further improve the uptake of nanoparticles by cells, a cell-penetrating peptide octaarginine (R8), which has been extensively exploited for the delivery of different liposomes and nanoparticles into living cells, [39][40][41][42][43] was conjugated onto the surface of amino groupfunctionalized Pd@Ag@SiO 2 (RITC)-NH 2 (denoted as Pd@Ag@SiO 2 (RITC)-R8) for enhancing cellular uptake of nanoparticles, further improving the optical imaging and PTT efficiency.…”