Gd-containing conjugated polymer nanoparticles: bimodal nanoparticles for fluorescence and MRI imaging

Abstract

Aqueous bifunctional semiconductor polymer nanoparticles (SPNs), approximately 30 nm in diameter (as measured from electron microscopy), were synthesised using hydrophobic conjugated polymers, amphiphilic phospholipids and a gadolinium-containing lipid. Their fluorescence quantum yields and extinction coefficients were determined, and their MRI T₁-weighted relaxation times in water were measured. The bimodal nanoparticles were readily taken up by HeLa and murine macrophage-like J774 cells as demonstrated by confocal laser scanning microscopy, and were found to be MRI-active, generating a linear relationship between T₁-weighted relaxation rates and gadolinium concentrations The synthesis is relatively simple, and can easily result in milligrams of materials, although we fully expect scale-up to the gram level to be easily realised.

Bright conjugated polymer nanoparticles containing a biodegradable shell produced at high yields and with tuneable optical properties by a scalable microfluidic device

“…Moreover, F8BT nanoparticles prepared microfluidically had significantly (p<0.05) higher quantum yields than those prepared by the solvent displacement technique (37 ± 1% and 34 ± 1% for [1.4] and [0.2], respectively). A similar quantum yield of 35.8% has been observed for F8BT nanoparticles containing gadolinium produced by a bulk technique 23 . We did not observe any relationship between the size distribution or emission spectra of F8BT nanoparticles and the measured quantum yield ( Figure 7C/D).…”

“…. These values are only 15% lower than those measured for the fully solvated F8BT dissolved in dichloromethane (68.6%) 23 . Moreover, F8BT nanoparticles prepared microfluidically had significantly (p<0.05) higher quantum yields than those prepared by the solvent displacement technique (37 ± 1% and 34 ± 1% for [1.4] and [0.2], respectively).…”

Nanoparticles in magnetic resonance imaging: from simple to dual contrast agents

“…Finally, nanoparticles can act as multifunctional MI agents, since they have two or more properties that can be used simultaneously in multiple imaging techniques, and especially in MRI. 14 …”

Advances in gadolinium-based MRI contrast agent designs for monitoring biological processes in vivo

“…The enhanced permeation and retention (EPR) effect of nanoparticle constructs plus facile targeting of a nanoparticle payload through surface modification add to the benefits of using nanoparticles to deliver MRI contrast agent to specific tissues. Gadolinium chelates have been attached via chemical or physical binding (electrostatic or encapsulation) to a variety of nanoparticles, including dendrimers [16–19], micelles [20,21], liposomes [22,23], polymeric [24–26] or inorganic nanoparticles [27,28], and nanogels [29–32]. Among those examples, the use of nanogels is particularly well suited for MRI as they are stable in aqueous media and allow facile access of water molecules throughout the particle.…”