This paper describes the evaluation of the auto-catalytic anti-oxidant behavior and biocompatibility of Cerium oxide nanoparticles for applications in spinal cord repair and other diseases of the CNS. The application of a single dose of nano-Ceria at a nano-molar concentration is biocompatible, regenerative and provides a significant neuroprotective effect on adult rat spinal cord neurons.Retention of neuronal function is demonstrated from electrophysiological recordings and the possibility of its application to prevent ischemic insult is suggested from an oxidative injury assay. A mechanism is proposed to explain the auto-catalytic properties of these nanoparticles.

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While much is known about muscle spindle structure, innervation and function, relatively few factors have been identified that regulate intrafusal fiber differentiation and spindle development. Identification of these factors will be a crucial step in tissue engineering functional muscle systems. In this study, we investigated the role of the growth factor, neuregulin 1-β-1 EGF (Nrg1-β-1), for its ability to influence myotube fate specification in a defined culture system utilizing the non-biological substrate DETA. Based on morphological and immunocytochemical criteria, Nrg 1-β-1 treatment of developing myotubes increases the ratio of nuclear bag fibers to total myotubes from 0.019 to 0.100, approximately a five-fold increase. The myotube cultures were evaluated for expression of the intrafusal fiber specific alpha cardiac-like myosin heavy chain and for the expression of the nonspecific slow myosin heavy chain. Additionally, the expression of ErbB2 receptors on all myotubes was observed, while phosphorylated ErbB2 receptors were only observed in Nrg1-β-1 treated intrafusal fibers. After Nrg1-β-1 treatment, we were able to observe the expression of the intrafusal fiber specific transcription factor Egr3 only in fibers exhibiting the nuclear bag phenotype. Finally, nuclear bag fibers were characterized electrophysiologically for the first time in vitro. This data shows conclusively, in a serum-free system, that Nrg 1-β-1 is necessary to drive specification of forming myotubes to the nuclear bag phenotype.

In this study, we have demonstrated a method to organize cells in dissociated cultures using engineered chemical clues on the culture surface and determined their connectivity patterns. Although almost all elements of the synaptic transmission machinery between neurons or between neurons and muscle fibers can be studied separately in single-cell models in dissociated cultures, the difficulty of clarifying the complex interactions between these elements makes random cultures not particularly suitable for specific studies. Factors affecting synaptic transmission are generally studied in organotypic cultures, brain slices, or in vivo where the cellular architecture generally remains intact. However, by utilizing engineered neuronal networks, complex phenomenon such as synaptic transmission can be studied in a simple, functional, cell culture-based system. We have utilized self-assembled monolayers (SAMs) and photolithography to create the surface templates. Embryonic hippocampal cells, plated on the resultant patterns in serum-free medium, followed the surface clues and formed the engineered neuronal networks. Basic electrophysiological methods were applied to characterize the synaptic connectivity in these engineered two-cell networks.

A very small population of Choline acetyltransferase (ChAT) immunoreactive cells is observed in all layers of the adult hippocampus. This is the intrinsic source of the hippocampal cholinergic innervation, in addition to the well-established septo-hippocampal cholinergic projection. This study aimed at quantifying and identifying the origin of this small population of ChAT-immunoreactive cells in the hippocampus at early developmental stages, by culturing the fetal hippocampal neurons in serum-free culture and on a patternable, synthetic silane substrate N-1 [3-(trimethoxysilyl) propyl] diethylenetriamine (DETA). Using this method a large proportion of glutamatergic (glutamate vesicular transporter, VGLUT1-immunoreactive) neurons, a small fraction of GABAergic (GABA-immunoreactive) neurons and a large proportion of cholinergic (ChAT-immunoreactive) neurons were observed in culture. Interestingly, most of the glutamatergic neurons which expressed glutamate vesicular transporter (VGLUT1) also co-expressed choline acetyltransferase (ChAT) proteins. On the contrary, when the cultures were double stained with GABA and ChAT, colocalization was not observed. Neonatal and adult rat hippocampal neurons were also cultured to verify whether these more mature neurons also co-express VGLUT1 and ChAT proteins in culture. Colocalization of VGLUT1 and ChAT in these relatively more mature neurons was not observed. One possible explanation for this observation is that the neurons have the ability to synthesize multiple neurotransmitters at a very early stage of development and then with time follows a complex, combinatorial strategy of electrochemical coding to determine their final fate.

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We have developed a method to organize cells in dissociated cultures using engineered chemical clues on a culture surface and determined their connectivity patterns. Although almost all elements of the synaptic transmission machinery can be studied separately in single cell models in dissociated cultures, the complex physiological interactions between these elements are usually lost. Thus, factors affecting synaptic transmission are generally studied in organotypic cultures, brain slices, or in vivo where the cellular architecture generally remains intact. However, by utilizing engineered neuronal networks complex phenomenon such as synaptic transmission or synaptic plasticity can be studied in a simple, functional, cell culture-based system. We have utilized self-assembled monolayers and photolithography to create the surface templates. Embryonic hippocampal cells, plated on the resultant patterns in serum-free medium, followed the surface clues and formed the engineered neuronal networks. Basic whole-cell patch-clamp electrophysiology was applied to characterize the synaptic connectivity in these engineered two-cell networks. The same technology has been used to pattern other cell types such as cardiomyocytes or skeletal muscle fibers.