Hydrophilic Quantum Dots Functionalized with Gd(III)-DO3A Monoamide Chelates as Bright and Effective T1-weighted Bimodal Nanoprobes.
Maria I A PereiraGoreti PereiraCamila A P MonteiroCarlos F G C GeraldesPaulo E Cabral FilhoCarlos L CesarAndré Alexandre de ThomazBeate S SantosGiovannia A L PereiraAdriana FontesPublished in: Scientific reports (2019)
Magnetic resonance imaging (MRI) is a powerful non-invasive diagnostic tool that enables distinguishing healthy from pathological tissues, with high anatomical detail. Nevertheless, MRI is quite limited in the investigation of molecular/cellular biochemical events, which can be reached by fluorescence-based techniques. Thus, we developed bimodal nanosystems consisting in hydrophilic quantum dots (QDs) directly conjugated to Gd(III)-DO3A monoamide chelates, a Gd(III)-DOTA derivative, allowing for the combination of the advantages of both MRI and fluorescence-based tools. These nanoparticulate systems can also improve MRI contrast, by increasing the local concentration of paramagnetic chelates. Transmetallation assays, optical characterization, and relaxometric analyses, showed that the developed bimodal nanoprobes have great chemical stability, bright fluorescence, and high relaxivities. Moreover, fluorescence correlation spectroscopy (FCS) analysis allowed us to distinguish nanosystems containing different amounts of chelates/QD. Also, inductively coupled plasma optical emission spectrometry (ICP - OES) indicated a conjugation yield higher than 75%. Our nanosystems showed effective longitudinal relaxivities per QD and per paramagnetic ion, at least 5 times [per Gd(III)] and 100 times (per QD) higher than the r1 for Gd(III)-DOTA chelates, suitable for T1-weighted imaging. Additionally, the bimodal nanoparticles presented negligible cytotoxicity, and efficiently labeled HeLa cells as shown by fluorescence. Thus, the developed nanosystems show potential as strategic probes for fluorescence analyses and MRI, being useful for investigating a variety of biological processes.
Keyphrases
- contrast enhanced
- magnetic resonance imaging
- single molecule
- energy transfer
- quantum dots
- high resolution
- magnetic resonance
- diffusion weighted imaging
- computed tomography
- gene expression
- fluorescence imaging
- cell cycle arrest
- pet imaging
- induced apoptosis
- high speed
- sensitive detection
- small molecule
- risk assessment
- photodynamic therapy
- positron emission tomography
- cross sectional
- climate change
- data analysis
- simultaneous determination