TY  - JOUR
AB  - Nanosized contrast agents for molecular imaging have attracted widespread interest for diagnostic applications with high resolution in medicine. However, many solid nanoparticles exhibit a great potential to induce toxicity, hindering their use for clinical applications. On the other hand, near-infrared (NIR) dyes have also been used for extensive biological applications, but show some limitations due to their poor aqueous stability, tendency to aggregation and rapid elimination from the body. An alternative proposed in this work to overcome these limitations is the use of NIR dye-loaded nanoparticles. Here we introduce nanoparticles constructed with poly(D,L-lactide-co-glycolic acid) (PLGA), a biodegradable and biocompatible polymer widely used for biomedical applications, attached to the polycation polyethyleneimine (PEI) to obtain positively charged nanoparticles. The in vivo biodistribution of the cationic PEI-PLGA nanoparticles was investigated after administration through three different routes (intravenous, intraperitoneal and subcutaneous) using multispectral optoacoustic tomography (MSOT). The prepared nanoparticles exhibited good colloidal stability and adequate optical properties for optoacoustic imaging. The in vivo biodistribution assays indicated a strong accumulation of the particles in the liver and spleen, and retention in these organs for at least 24 h. Therefore, these nanoparticles could find promising applications in MSOT due to a sharp and characteristic optoacoustic spectrum and high optoacoustic signal generation, and become a promising building block for theranostic strategies.
AU  - Egusquiaguirre, S.P.*
AU  - Bézière, N.
AU  - Pedraz, J.L.*
AU  - Hernández, R.M.*
AU  - Ntziachristos, V.
AU  - Igartua, M.*
C1  - 45051
C2  - 37192
SP  - 421-427
TI  - Optoacoustic imaging enabled biodistribution study of cationic polymeric biodegradable nanoparticles.
JO  - Contrast Media Mol. Imaging
VL  - 10
IS  - 6
PY  - 2015
SN  - 1555-4309
ER  - 

TY  - JOUR
AB  - In this study we report the development of a bioconjugate between superparamagnetic iron oxide nanoparticles and Phl p5a (one of the major allergens from grass pollen). The bioconjugate also contains an optical probe (Alexa647) conjugated to the nanoparticle via biotinstreptavidin association. We show that this conjugate has a range of features that makes it a very promising candidate to image the localization of this allergen in vivo: (a) upon conjugation to the iron oxide nanoparticles, the allergen retains its ability to interact with IgE antibodies; (b) the magnetic properties of the iron oxide core of this bioconjugate are suitable for MR imaging; and (c) Alexa647 fluorophore retains its emission properties once attached to the iron oxide nanoparticles, yielding a dual modality MRI-optical probe.
AU  - Herranz, F.*
AU  - Schmidt-Weber, C.B.
AU  - Shamji, M.H.*
AU  - Narkus, A.*
AU  - Ruiz-Cabello, J.*
AU  - Vilar, R.*
C1  - 7547
C2  - 30130
SP  - 435-439
TI  - Superparamagnetic iron oxide nanoparticles conjugated to a grass pollen allergen and an optical probe.
JO  - Contrast Media Mol. Imaging
VL  - 7
IS  - 4
PB  - Wiley-Blackwell
PY  - 2012
SN  - 1555-4309
ER  - 

TY  - JOUR
AB  - Thermosensitive liposomes (TSL) with encapsulated proton (1H) magnetic resonance (MR) contrast agents have been proposed for noninvasive online temperature monitoring during tumor treatment using chemotherapy combined with hyperthermia (HT). The technique exploits the fact that water exchange between the TSL interior and exterior is increased and/or the encapsulated 1H MR contrast agent is released near the gel-to-liquid crystalline phase transition temperature (Tm) of TSL and thus shortens the 1H MR relaxation time of tissue. In this work, newly developed, phosphatidylglyceroglycerol (DPPGOG)-based TSL with encapsulated 1H MR longitudinal relaxation time (T1)-shortening gadodiamide (Gd-DTPA-BMA) were characterized in vitro by measuring the temperature dependence of the T1 of these gadodiamide-containing DPPGOG-TSL samples between 30 and 50 degrees C. The measurements revealed that the T1 nonlinearly slightly decreased with increasing temperature from 30 to 37 degrees C, mainly due to increased water exchange between the gadodiamide-containing DPPGOG-TSL interior and exterior with the exception of negligible gadodiamide release. This implies that gadodiamide-containing DPPGOG-TSL were stable at temperatures < or =37 degrees C, which was also confirmed by an independent stability study. From 37 to 44 degrees C, the T1 nonlinearly markedly decreased with increasing temperature since encapsulated gadodiamide was rapidly released. Above 44 degrees C, gadodiamide was completely released and the T1 was directly proportional to temperature while heated from 44 to 50 degrees C and cooled from 50 to 30 degrees C, respectively. Additionally, gadodiamide release was theoretically quantified and this calculated concentration was consistent with the actually released amount directly obtained from the cooling course of empty DPPGOG-TSL with completely released gadodiamide.
AU  - Wang, T.*
AU  - Hossann, M.*
AU  - Reinl, H.M.
AU  - Peller, M.*
AU  - Eibl, H.*
AU  - Reiser, M.*
AU  - Issels, R.D.
AU  - Lindner, L.H.
C1  - 648
C2  - 25214
SP  - 19-26
TI  - In vitro characterization of phosphatidylglyceroglycerol-based thermosensitive liposomes with encapsulated 1H MR T1-shortening gadodiamide.
JO  - Contrast Media Mol. Imaging
VL  - 3
IS  - 1
PB  - Wiley-Blackwell
PY  - 2008
SN  - 1555-4309
ER  -