A new ex vivo method to evaluate the performance of candidate MRI contrast agents: a proof-of-concept study

Abstract

BackgroundMagnetic resonance imaging (MRI) plays an important role in tumor detection/diagnosis. The use of exogenous contrast agents (CAs) helps to improve the discrimination between lesion and neighbouring tissue, but most of the currently available CAs are non-specific. Assessing the performance of new, selective CAs requires exhaustive assays and large amounts of material. Accordingly, in a preliminary screening of new CAs, it is important to choose candidate compounds with good potential for in vivo efficiency. This screening method should reproduce as close as possible the in vivo environment. In this sense, a fast and reliable method to select the best candidate CAs for in vivo studies would minimize time and investment cost, and would benefit the development of better CAs.ResultsThe post-mortem ex vivo relative contrast enhancement (RCE) was evaluated as a method to screen different types of CAs, including paramagnetic and superparamagnetic agents. In detail, sugar/gadolinium-loaded gold nanoparticles (Gd-GNPs) and iron nanoparticles (SPIONs) were tested. Our results indicate that the post-mortem ex vivo RCE of evaluated CAs, did not correlate well with their respective in vitro relaxivities. The results obtained with different Gd-GNPs suggest that the linker length of the sugar conjugate could modulate the interactions with cellular receptors and therefore the relaxivity value. A paramagnetic CA (GNP (E_2)), which performed best among a series of Gd-GNPs, was evaluated both ex vivo and in vivo. The ex vivo RCE was slightly worst than gadoterate meglumine (201.9 ± 9.3% versus 237 ± 14%, respectively), while the in vivo RCE, measured at the time-to-maximum enhancement for both compounds, pointed to GNP E_2 being a better CA in vivo than gadoterate meglumine. This is suggested to be related to the nanoparticule characteristics of the evaluated GNP.ConclusionWe have developed a simple, cost-effective relatively high-throughput method for selecting CAs for in vivo experiments. This method requires approximately 800 times less quantity of material than the amount used for in vivo administrations.

Drought Impact Is Alleviated in Sugar Beets (Beta vulgaris L.) by Foliar Application of Fullerenol Nanoparticles

“…These authors also observed high mobility of carbon nanoparticles inside plant and seed tissues. In general, CBNMs have been found to be highly mobile in plant tissues, depending on the applied nanoparticle [8,59]. Further biochemical, genomic and proteomic studies are needed to fully understand FNPs mobility and physiological activities in plants.…”

“…Among these, carbon based nanomaterials (CBNMs) have been the focus of several studies in recent years, and have been shown to be helpful in both agriculture and biotechnology [7,8]. The most investigated CBNMs are fullerene (C 60 and C 70 ), fullerenol C 60 (OH) x , x = 18–36 and CNTs.…”

“…The most investigated CBNMs are fullerene (C 60 and C 70 ), fullerenol C 60 (OH) x , x = 18–36 and CNTs. Although some studies have reported positive effects on plant growth and development in crop plants associated with application of CBNMs, few studies have addressed how fullerene molecules and their derivates may affect plants [8,9]. …”

Development of a Larvicidal Nanoemulsion with Pterodon emarginatus Vogel Oil

“…Classical chemical reactions may be used, giving rise to water soluble compounds such as forming terpenoid salts [ 41 ]. Another strategy relies on the development of stable nanosystems, which can improve water solubility of these substances by entrapping then into micelles with nano-size diameter [ 42 ]. Nanobiotechnology is an emerging area with great potential for innovative products, including eco-friendly pesticides.…”

r1andr2Relaxivities of Dendrons Based on a OEG-DTPA Architecture: Effect of Gd3+Placement and Dendron Fun

“…Indeed, a factor of ca. 3-fold decrease in 1 has been described for nanoparticulated Gd quelates between 1.4 and 7 [20]. Still, additional contributions could come from the fact that compounds described in [18] were glyconjugates, providing second-sphere water molecules close to the chelated Gd, with increased bulk relaxivity.…”