Upconverting Nanoparticle to Quantum Dot Förster Resonance Energy Transfer: Increasing the Efficiency through Donor Design

We propose two effective approaches to enhance the Förster resonance energy transfer (FRET) efficiency from near-infrared excited upconverting nanoparticles (UCNPs, namely, LiYF4:Yb3+,Tm3+) to CuInS2 quantum dots (QDs) upon engineering of the donor’s architecture. The study of the particles’ interaction highlighted a radiative nature of the energy transfer among the moieties under investigation when in solution. However, analyses performed on dry powders allowed observing clear evidence of a FRET mechanism. In particular, photoluminescence lifetime measurements showed that FRET efficiency could be effectively increased by both reducing the size of the UCNPs and directly controlling the distribution of the active ions throughout the donor’s volume, i.e., doping them only in the outer shell of a core/shell system. Both strategies resulted at least in a more than doubled FRET efficiency compared to larger core-only UCNPs. Obtained experimental values were compatible with those predicted from geometrical considerations on the active ions’ distribution over the UCNP volume. These results provide a concrete proof of the potential of a UCNP–QD FRET pair when the system is properly designed, hence setting a solid base for the development of robust and efficient all-inorganic probes for FRET-based assays

NG2 cells in an animal model of congenital hydrocephalus

Comunicación oral. El resumen no se publica por deseo de los autoresNG2 cells are considered oligodendrocyte precursor cells (OPC). In pathological conditions, NG2 cells contribute to generate oligodendrocytes and reactive astrocytes. This study has been designed to uncover the role of NG2 cells in congenital hydrocephalus using the hyh mouse model. Materials and methods Brain sections and whole mount preparations were obtained from embryos and postnatal hyh and control mice. NG2 positive (NG2+) cells were co-labelled with different IHC markers to deepest identification. Additionally, trying to understand reproducibility of our results in different neurodegenerative conditions, same NG2 identification approach was performed using ventricular walls explants from control mice after mechanical induction of astrocyte reaction. Results A higher number of NG2+ cells were found in the hyh mice compared to the control mice. In addition, NG2+ cells in the hyh mice showed a higher NG2 antigen content compared to the control mice. In the hyh mouse, colocalization results showed that most of NG2+ cells were identified as OPC cells and pericytes, but never as reactive astrocytes o microglial cells. However, in the same approach performed in neurodegenerative conditions, NG2+ cells were mostly identified as reactive astrocytes. Conclusions NG2 progenitors appear to be affected in hyh mutant mice giving rise to a different NG2+population which role in hydrocephalus is still unkown.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Effect of bone marrow-derived mesenchymal stem cells on congenital hydrocephalus in the hyh mouse

Background Bone marrow-derived mesenchymal stem cells (BM-MSC) are considered as a potential therapeutic tool for neurodegenerative diseases due to their ability for migrating into damaged tissue. Additionally, these cells have been proven to produce neuroprotective factors when they are transplanted into damaged tissue. In this research we uncover a neuroprotective role of BM-MSC on congenital hydrocephalus and we study the molecular mechanisms behind it. Materials and methods Fluorescent BM-MSC were analyzed by flow-cytometry and multilineage cell differentiation. They were brain-ventricle injected into hyh hydrocephalic mice. Wild-type and saline-injected hyh mice were used as controls. Inmunohistochemical analyses were performed in fixed brain sections. Inflammatory reaction and neuroprotective factors were studied using quantitative RT-PCR. Metabolites and osmolytes related to brain damage were studied by High Resolution Magic Angle Spinning spectroscopy (HRMAS). RT-PCR and HRMAS were performed in fresh tissue. Results Integrated BM-MSC were identified inside the periventricular astrocyte reaction. IL-1alpha/beta and IL6 levels indicated the absence of inflammatory response in the transplanted tissue after BM-MSC integration. BM-MSC were found producing neuroprotective factors, including GDNF, NGF, BDNF and VEGF. Reduction of osmolytes and neural/glial-function related metabolites levels were detected in hyh mice after BM-MSC injection. These levels mimicked the wild-type situation and indicate partial recovery. Conclusions The BM-MSC can play a neuroprotective effect on congenital hydrocephalus in the hyh mouse by the production of neuroprotective factors and the reduction of osmolytes and metabolites related to tissue damage.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech