Neuronal Cell Growth Research Articles

DHA Effects in Brain Development and Function.

Docosahexaenoic acid (DHA) is a structural constituent of membranes specifically in the central nervous system. Its accumulation in the fetal brain takes place mainly during the last trimester of pregnancy and continues at very high rates up to the end of the second year of life. Since the endogenous formation of DHA seems to be relatively low, DHA intake may contribute to optimal conditions for brain development. We performed a narrative review on research on the associations between DHA levels and brain development and function throughout the lifespan. Data from cell and animal studies justify the indication of DHA in relation to brain function for neuronal cell growth and differentiation as well as in relation to neuronal signaling. Most data from human studies concern the contribution of DHA to optimal visual acuity development. Accumulating data indicate that DHA may have effects on the brain in infancy, and recent studies indicate that the effect of DHA may depend on gender and genotype of genes involved in the endogenous synthesis of DHA. While DHA levels may affect early development, potential effects are also increasingly recognized during childhood and adult life, suggesting a role of DHA in cognitive decline and in relation to major psychiatric disorders.

Study of electrical conductivity of collagen I, chitosan and blends supported on carbon fibers for biomedical applications

Event Abstract Back to Event Study of electrical conductivity of collagen I, chitosan and blends supported on carbon fibers for biomedical applications Eduardo Arruda1, Jossano Marcuzzo2, 3, João D. Oliveira Ventura4, Jose Tiago Teixeira Cardoso4, Catarina Jose Loureiro Da Silva Dias4, Marisa Masumi Beppu5, Fernando Jorge Mendes Monteiro6, 7 and Giovana M. Genevro5 1 UFGD, FACET-Química, Brazil 2 FATEC - SJC, Faculdades de Tecnologia de São Paulo, Brazil 3 INPE, Instituto Nacional de Pesquisas Espaciais - INPE, Brazil 4 UP, Faculdade de Ciências da Universidade do Porto - FCUP, Portugal 5 UNICAMP, Faculdade de Engenharia Quimica - FEQ, Brazil 6 UP, Faculdade de Engenharia da Universidade do Porto - FEUP, Portugal 7 UP, Instituto de Engenharia Biomédica-INEB/i3S, Portugal Introduction: Non-activated Carbon Fibers (NACF) and Activated (ACF) can be used as conductive supports for scaffolds with collagen I, chitosan and their blends for biomedical applications. Carbon fibers have interesting multifunctional characteristics, as: (i) self-supporting structures, (ii) electrical conductivity associated with surface composition, (iii) filament shape and (iv) high porosity. Materials and Methods: NACF and ACF were prepared by Marcuzzo method [1] by thermal processes in controlled atmosphere from PAN (polyacrylonitrile). Briefly, PAN fiber was turned into fiber felts by oxidation, carbonization and activation processes. We used 3D arranged carbon fibers that turn this material into a conductivity scaffold [2]. Fibers size and graphitic domains (microcrystallites) enable multiple applications. The electrical characteristics of carbon fibers felt were determined before and after the impregnation of collagen I, chitosan and blends of 2.5% acetic solutions in the proportions from 1:4, to 3:1 (w/w) to analyse the biological activity, adhesion, growth and proliferation of cardiac, neuronal and osteogenic cells by electrical conduction and/or electrical stimulation. Results: Resistivity (conductivity) was measured using the Van der Pauw method [3] with fixed electrodes at the samples perimeter. Electrical measurements were performed for samples after impregnation coating process on the NACF fibers (Fig. 1). Fig. 1. SEM micrographs A) NACF 250x, B) ACF 250x, C) NACF:Collagen I 250x, D) NACF:Chitosan 250x, E) NACF:Collagen I:Chitosan (1:1) 250x and F) NACF:Collagen I:Chitosan (3:1) 250x The conductivities were: NACF 1,91E-03 Ω.m (5.23 S cm-1); ACF 2,06E-03 Ω.m (4.86 S cm-1); NACF:Collagen I 1,82E-03 Ω.m (5.49 S cm-1); NACF:Chitosan 1,85E-03 Ω.m (5.40 S cm-1); Collagen I:Chitosan:NACF (1:1) 2,03E-03 Ω.m (4.92 S cm-1); (1:2) 1,80E-03 Ω.m (5.56 S cm-1); (1:3) 1,68E-03 Ω.m (5.94 S cm-1); (1:4) 1,57E-03 Ω.m (6.36 S cm-1); (2:1) 1.79E-03 Ω.m (5.60 S cm-1) and (3:1) 1.81E-03 Ω.m (5.54 S cm-1). The elemental composition found by X-ray Photoelectron Spectroscopy (XPS) were: NACF (C 95.87%, O 2.80%, N 1.20%), ACF (C 97.54%, O 1.90%, N 0.56%) and for 1:1 blend (C 78.00%, O 16.84%, N 5.15%). Conclusion: The results show the influence of polymers and their blends in the conductivity of NACF fiber used as graphitic conductive framework to produce scaffolds by impregnation or deposition. These fibers may be used as a biomaterial for the induction of growth and/or cell differentiation, regenerative processes involving cell communication and/or for induction of growth/cell differentiation by electrostimulation. CAPES/FCT; FEQ/UNICAMP; FEUP; INEB; FCUP/Física; INPE; FAPESP; FATECSP; CNPq

Aligned Electroactive TMV Nanofibers as Enabling Scaffold for Neural Tissue Engineering.

Electroactive nanofibers were fabricated by in situ polymerization of aniline on the surface of tobacco mosaic virus (TMV) using sodium poly(styrenesulfonate) (PSS) as dopant. These electroactive TMV/PANi/PSS nanofibers were employed to support growth of neuronal cells, resulting in augmentation of the length of neurites. In addition, the percentage of cells with neurites was increased in comparison to cells cultured on TMV-derived nonconductive nanofibers. The TMV-based electroactive nanofibers could be aligned in capillaries that could guide the outgrowth direction of neurites, increase the percentage of cells with neurites, and lead to a bipolar cellular morphology. Our results demonstrate that the electroactivity and topographical cues provided by TMV/PANi/PSS nanofibers can synergistically stimulate neural cells differentiation and neurites outgrowth, which make it a promising scaffolding material for neural tissue engineering.

Non-canonical Hedgehog/AMPK-Mediated Control of Polyamine Metabolism Supports Neuronal and Medulloblastoma Cell Growth

Developmental Hedgehog signaling controls proliferation of cerebellar granule cell precursors (GCPs), and its aberrant activation is a leading cause of medulloblastoma. We show here that Hedgehog promotes polyamine biosynthesis in GCPs by engaging a non-canonical axis leading to the translation of ornithine decarboxylase (ODC). This process is governed by AMPK, which phosphorylates threonine 173 of the zinc finger protein CNBP in response to Hedgehog activation. Phosphorylated CNBP increases its association with Sufu, followed by CNBP stabilization, ODC translation, and polyamine biosynthesis. Notably, CNBP, ODC, and polyamines are elevated in Hedgehog-dependent medulloblastoma, and genetic or pharmacological inhibition of this axis efficiently blocks Hedgehog-dependent proliferation of medulloblastoma cells in vitro and in vivo. Together, these data illustrate an auxiliary mechanism of metabolic control by a morphogenic pathway with relevant implications in development and cancer.

Biomimetic Microelectronics for Regenerative Neuronal Cuff Implants.

Smart biomimetics, a unique class of devices combining the mechanical adaptivity of soft actuators with the imperceptibility of microelectronics, is introduced. Due to their inherent ability to self-assemble, biomimetic microelectronics can firmly yet gently attach to an inorganic or biological tissue enabling enclosure of, for example, nervous fibers, or guide the growth of neuronal cells during regeneration.

Bridging the lesion-engineering a permissive substrate for nerve regeneration.

Biomaterial-based strategies to restore connectivity after lesion at the spinal cord are focused on bridging the lesion and providing an favourable substrate and a path for axonal re-growth. Following spinal cord injury (SCI) a hostile environment for neuronal cell growth is established by the activation of multiple inhibitory mechanisms that hamper regeneration to occur. Implantable scaffolds can provide mechanical support and physical guidance for axon re-growth and, at the same time, contribute to alleviate the hostile environment by the in situ delivery of therapeutic molecules and/or relevant cells. Basic research on SCI has been contributing with the description of inhibitory mechanisms for regeneration as well as identifying drugs/molecules that can target inhibition. This knowledge is the background for the development of combined strategies with biomaterials. Additionally, scaffold design is significantly evolving. From the early simple hollow conduits, scaffolds with complex architectures that can modulate cell fate are currently being tested. A number of promising pre-clinical studies combining scaffolds, cells, drugs and/or nucleic acids are reported in the open literature. Overall, it is considered that to address the multi-factorial inhibitory environment of a SCI, a multifaceted therapeutic approach is imperative. The progress in the identification of molecules that target inhibition after SCI and its combination with scaffolds and/or cells are described and discussed in this review.

Effects of low- and high-frequency repetitive magnetic stimulation on neuronal cell proliferation and growth factor expression: A preliminary report

Repetitive magnetic stimulation is a neuropsychiatric and neurorehabilitation tool that can be used to investigate the neurobiology of sensory and motor functions. Few studies have examined the effects of repetitive magnetic stimulation on the modulation of neurotrophic/growth factors and neuronal cells in vitro. Therefore, the current study examined the differential effects of repetitive magnetic stimulation on neuronal cell proliferation as well as various growth factor expression. Immortalized mouse neuroblastoma cells were used as the cell model in this study. Dishes of cultured cells were randomly divided into control, sham, low-frequency (0.5Hz, 1Tesla) and high-frequency (10Hz, 1Tesla) groups (n=4 dishes/group) and were stimulated for 3 days. Expression of neurotrophic/growth factors, Akt and Erk was investigated by Western blotting analysis 3 days after repetitive magnetic stimulation. Neuroblastoma cell proliferation was determined with a cell counting assay. There were differences in cell proliferation based on stimulus frequency. Low-frequency stimulation did not alter proliferation relative to the control, while high-frequency stimulation elevated proliferation relative to the control group. The expression levels of brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), neurotrophin-3 (NT-3) and platelet-derived growth factor (PDGF) were elevated in the high-frequency magnetic stimulation group. Akt and Erk expression was also significantly elevated in the high-frequency stimulation group, while low-frequency stimulation decreased the expression of Akt and Erk compared to the control. In conclusion, we determined that different frequency magnetic stimulation had an influence on neuronal cell proliferation via regulation of Akt and ERK signaling pathways and the expression of growth factors such as BDNF, GDNF, NT-3 and PDGF. These findings represent a promising opportunity to gain insight into how different frequencies of repetitive magnetic stimulation may mediate cell proliferation.

Laser fabricated discontinuous anisotropic microconical substrates as a new model scaffold to control the directionality of neuronal network outgrowth

Patterning of neuronal outgrowth in vitro is important in tissue engineering as well as for the development of neuronal interfaces with desirable characteristics. To date, this has been achieved with the aid of micro- and nanofabrication techniques giving rise to various anisotropic topographies, either in the form of continuous or discontinuous structures. In this study we propose a currently unexplored geometry of a 3D culture substrate for neuronal cell growth comprising discontinuous subcellular microstructures with anisotropic geometrical cross-section. Specifically, using laser precision 3D micro/nano fabrication techniques, silicon substrates comprising arrays of parallel oriented elliptical microcones (MCs) were fabricated to investigate whether a discontinuous geometry comprising anisotropic features at the subcellular level could influence the alignment of peripheral nervous system cell populations. It was shown that both Schwann cells and axons of sympathetic neurons were parallel oriented onto the MCs of elliptical shape, while they exhibited a random orientation onto the MCs of arbitrary shape. Notably, this topography-induced guidance effect was also observed in more complex cell culture systems, such as the organotypic culture whole dorsal root ganglia (DRG) explants. Our results suggest that a discontinuous topographical pattern could promote Schwann cell and axonal alignment, provided that it hosts anisotropic geometrical features, even though the sizes of those range at the subcellular lengthscale. The laser-patterned arrays of MCs presented here could potentially be a useful platform for patterning neurons into artificial networks, allowing the study of neuronal cells interactions under 3D ex-vivo conditions.

General Characteristics of Taurine: A Review

Taurine is one of the most abundant free -amino acids in the human body that accounts for 0.1% of the human body weight. It has a sulfonic acid group in place of the more common carboxylic acid group. Mollusks and meat are the major dietary source of taurine, and mother`s milks also include high levels of this amino acid. The leukocytes, heart, muscle, retina, kidney, bone, and brain contain more taurine than other organs. Furthermore, taurine can be synthesized in the brain and liver from cysteine. There are no side effects of excessive taurine intake in humans; however, in case of taurine deficiency, retinal abnormalities, reduced plasma taurine concentration, and other abnormalities may occur. Taurine enters the cell via a cell membrane receptor. It is excreted in the urine (approximately 95%) and feces (approximately 5%). Taurine has a number of features and functions, including conjugation with bile acid, reduction of blood cholesterol and triglyceride levels, promotion of neuron cell differentiation and growth, antioxidant effects, maintenance of cell membrane stability, retinal development, energy generation, depressant effects, regulation of calcium level, muscle contraction and relaxation, bone formation, anti-inflammatory effects, anti-cancer and anti-atherogenic effects, and osmotic pressure control. However, the properties, functions, and effects of taurine require further studies in future.

Non-Faradaic electrical impedimetric investigation of the interfacial effects of neuronal cell growth and differentiation on silicon nanowire transistors.

Silicon nanowire field-effect transistor (SiNW FET) devices have been interfaced with cells; however, their application for noninvasive, real-time monitoring of interfacial effects during cell growth and differentiation on SiNW has not been fully explored. Here, we cultured rat adrenal pheochromocytoma (PC12) cells, a type of neural progenitor cell, directly on SiNW FET devices to monitor cell adhesion during growth and morphological changes during neuronal differentiation for a period of 5-7 d. Monitoring was performed by measuring the non-Faradaic electrical impedance of the cell-SiNW FET system using a precision LCR meter. Our SiNW FET devices exhibited changes in impedance parameters during cell growth and differentiation because of the negatively charged cell membrane, seal resistance, and membrane capacitance at the cell/SiNW interface. It was observed that during both PC12 cell growth and neuronal differentiation, the impedance magnitude increased and the phase shifted to more negative values. However, impedance changes during cell growth already plateaued 3 d after seeding, while impedance changes continued until the last observation day during differentiation. Our results also indicate that the frequency shift to above 40 kHz after growth factor induction resulted from a larger coverage of cell membrane on the SiNWs due to distinctive morphological changes according to vinculin staining. Encapsulation of PC12 cells in a hydrogel scaffold resulted in a lack of trend in impedance parameters and confirmed that impedance changes were due to the cells. Moreover, cytolysis of the differentiated PC12 cells led to significant changes in impedance parameters. Equivalent electrical circuits were used to analyze the changes in impedance values during cell growth and differentiation. The technique employed in this study can provide a platform for performing investigations of growth-factor-induced progenitor cell differentiation.

Crypteins--an overlooked piece of peptide systems.

Crypteins, the hidden bioactive sequences, play an important role in the modulation of various biological processes, such as neuronal signaling, angiogenesis, immune response, inflammatory response and cell growth. Proteolytic mechanism leading to the release of crypteins possessing novel biological activities is an important factor for increasing diversity of functional molecules and represents a potential new source of peptide drugs. In this work we would like to focus on crypteins derived from the already known precursors and their potential therapeutic value.

The pattern of c-Fos expression and its refractory period in the brain of rats and monkeys.

Intense activation of neurons triggers the appearance of immediate expression genes, including c-Fos. This gene is related to various signal cascades involved in biochemical processes such as neuronal plasticity, cell growth and mitosis. Here we investigate the expression pattern and the refractory period of c-Fos in rats and monkey’s brains after stimulation with pentylenetetrazol. Rats and monkeys were sacrificed at various times after PTZ-induced seizure. Here we show that rats and monkeys already showed c-Fos expression at 0.5 h after seizure. Yet, the pattern of protein expression was longer in monkeys than rats, and also was not uniform (relative intensity) across different brain regions in monkeys as opposed to rats. In addition monkeys had a regional brain variation with regard to the temporal profile of c-Fos expression, which was not seen in rats. The refractory period after a second PTZ stimulation was also markedly different between rats and monkeys with the latter even showing a summatory effect on c-Fos expression after a second stimulation. However, assessment of c-Fos mRNA in rats indicated a post-transcriptional control mechanism underlying the duration of the refractory period. The difference in the protein expression pattern in rodents and primates characterizes a functional aspect of brain biochemistry that differs between these mammalian orders and may contribute for the more developed primate cognitive complexity as compared to rodents given c-Fos involvement in cognitive and learning tasks.

Thermoswitching microgel carriers improve neuronal cell growth and cell release for cell transplantation.

Successful cell replacement therapy in the central nervous system (CNS) depends on both the transplanted cell type and the cell delivery method. It was established that differentiated neurons are the most desirable cell source; however, they are highly sensitive to dissociation shear; removing them from the growth surface inflicts serious damage, rendering them less viable for transplantation. Pilot experiments using glass colloids as injectable cell carriers for cell transplantation in the adult rat hippocampus have greatly improved neuron survival and long-term neuron integration. However, these early studies have highlighted glass particle shortcomings. They are uncompressible, and, thus, only a small number of beads can be injected, limiting the transplanted cell number. Moreover, they remain permanently in the brain. To improve colloidal carriers properties for cell transplantation and establish a basis for the next generation of cell delivery supports, we have designed a broadly applicable engineering strategy to enable neuronal cell growth on and release from hydrogel particles before transplantation. Here, we describe poly(N-isopropylacrylamide) (pNIPAM) particle preparation, and we demonstrate that these hydrogel particles both facilitate manipulation of neurons and enable the increase in the number of viable transplanted cells in the young adult rat hippocampus. The absence of long-term cell association to beads suggested that pNIPAM thermoswitching properties enable the separation of cells from the beads during injection, which minimizes the number of injected carriers. Contrary to observations with glass carriers, no particle clumping was observed at the injection site, which indicates minimal risk of long-term inflammatory responses. Taken together, the properties of hydrogel particles make them a promising micro-carrier to improve neuronal cell transplantation.

Enhanced neuronal cell differentiation combining biomimetic peptides and a carbon nanotube-polymer scaffold

Carbon nanotubes are attractive candidates for the development of scaffolds able to support neuronal growth and differentiation thanks to their ability to conduct electrical stimuli, to interface with cells and to mimic the neural environment. We developed a biocompatible composite scaffold, consisting of multi-walled carbon nanotubes dispersed in a poly-l-lactic acid matrix able to support growth and differentiation of human neuronal cells. Moreover, to mimic guidance cues from the neural environment, we also designed synthetic peptides, derived from L1 and LINGO1 proteins. Such peptides could positively modulate neuronal differentiation, which is synergistically improved by the combination of the nanocomposite scaffold and the peptides, thus suggesting a prototype for the development of implants for long-term neuronal growth and differentiation. From the Clinical EditorThe study describes the design and preparation of nanocomposite scaffolds with multi-walled carbon nanotubes in a poly-L-lactic acid matrix. This compound used in combination with peptides leads to synergistic effects in supporting neuronal cell growth and differentiation.

Toward intelligent synthetic neural circuits: directing and accelerating neuron cell growth by self-rolled-up silicon nitride microtube array.

In neural interface platforms, cultures are often carried out on a flat, open, rigid, and opaque substrate, posing challenges to reflecting the native microenvironment of the brain and precise engagement with neurons. Here we present a neuron cell culturing platform that consists of arrays of ordered microtubes (2.7–4.4 μm in diameter), formed by strain-induced self-rolled-up nanomembrane (s-RUM) technology using ultrathin (<40 nm) silicon nitride (SiNx) film on transparent substrates. These microtubes demonstrated robust physical confinement and unprecedented guidance effect toward outgrowth of primary cortical neurons, with a coaxially confined configuration resembling that of myelin sheaths. The dynamic neural growth inside the microtube, evaluated with continuous live-cell imaging, showed a marked increase (20×) of the growth rate inside the microtube compared to regions outside the microtubes. We attribute the dramatic accelerating effect and precise guiding of the microtube array to three-dimensional (3D) adhesion and electrostatic interaction with the SiNx microtubes, respectively. This work has clear implications toward building intelligent synthetic neural circuits by arranging the size, site, and patterns of the microtube array, for potential treatment of neurological disorders.

Ouabain improves functional recovery following traumatic brain injury.

The cardiac steroid ouabain binds to Na(+), K(+)-ATPase and inhibits its activity. Administration of the compound to animals and humans causes an increase in the force of contraction of heart muscle and stabilizes heart rate. In addition, this steroid promotes the growth of cardiac, vascular, and neuronal cells both in vitro and in vivo. We studied the effects of ouabain on mouse recovery following closed head injury (CHI), a model for traumatic brain injury. We show that chronic (three times a week), but not acute, intraperitoneal administration of a low dose (1 μg/kg) of ouabain significantly improves mouse recovery and functional outcome. The improvement in mouse performance was accompanied by a decrease in lesion size, estimated 43 d following the trauma. In addition, mice that underwent CHI and were treated with ouabain showed an increase in the number of proliferating cells in the subventricular zone and in the area surrounding the site of injury. Determination of the identity of the proliferating cells in the area surrounding the trauma showed that whereas there was no change in the proliferation of endothelial cells or astrocytes, neuronal cell proliferation almost doubled in the ouabain-treated mice in comparison with that of the vehicle animals. These results point to a neuroprotective effects of low doses of ouabain and imply its involvement in brain recovery and neuronal regeneration. This suggests that ouabain and maybe other cardiac steroids may be used for the treatment of traumatic brain injury.

Enhancement of primary neuronal cell proliferation using printing-transferred carbon nanotube sheets.

Artificial nerve guidance conduits (aNGCs) prepared from polymer scaffolds and carbon nanotubes (CNTs) possess unique chemical and physical properties, and have been widely used in preclinical trials to promote neuronal differentiation and growth. However, there have been only a few reports on the clinical applicability of CNT sheets for proliferation of primary neuronal cells due to safety concerns. The present study assesses the ability and potential applicability of multiwalled CNTs (MWNTs) composited with polydimethylsiloxane (PDMS) sheets to promote and enhance the proliferation of primary neuronal cells. In this study, the aqueous MWNT dispersion was filtered, and the PDMS/MWNT sheets were prepared using a simple printing transfer method. Characterization of PDMS/MWNT sheets demonstrated their unique physical properties such as superior mechanical strength and electroconductivity when compared with PDMS sheets. The effect of the PDMS/MWNT sheets on the neural cell proliferation and cytotoxicity was evaluated using MTT and alamar blue assays. Our results indicate the viability and proliferation of primary neuronal cells and Schwann cells in PDMS/MWNT sheets increased over twice when compared with a noncoated dish that is not usual in the primary neuronal cell growth control (p < 0.05). In addition, PDMS/MWNT sheets enhanced the adhesion and viability of the cells compared with poly-l-lysine coated dishes, which are most commonly used for improving cell adherence. Additionally, the PDMS/MWNT sheets exhibited excellent biocompatibility for culturing neuronal and Schwann cells. Overall, all assessments indicate that PDMS/MWNT sheets are ideal candidates for the development of artificial nerve conduits for clinical use following peripheral nerve injury.

Microfluidic spinning of grooved microfiber for guided neuronal cell culture using surface tension mediated grooved round channel

Microfibers with groove structure enable the guided culture of diverse cells. For the fabrication of grooved microfibers, microchannel with a few microscale groove structure needs to be fabricated using complicated photolithography processes. In this study, a novel method to fabricate a round channel embedded microfluidic device for generating continuous grooved microfibers is introduced. The surface tension of PDMS prepolymer was used to construct the round channels and groove patterned structures in the microfluidic device. The self-organized multidroplet structures were utilized to engrave the groove on the microfiber without any complex procedure. Using the device, the groove patterned (ca.10 μm of pattern size) microfiber was successfully fabricated. Microfibers were continuously produced without clogging and the diameters of the grooved microfibers were varied with the flow rate. For the test of usability for cell alignment, fibers were coated with laminin and the neuro-progenitor cells from prenatal rat were seeded on the prepared grooved fibers and cultured. The guided growth of neuronal cells on the fiber was observed through the immunostaining with neurofilament.

Fabrication of planarised conductively patterned diamond for bio-applications

The development of smooth, featureless surfaces for biomedical microelectronics is a challenging feat. Other than the traditional electronic materials like silicon, few microelectronic circuits can be produced with conductive features without compromising the surface topography and/or biocompatibility. Diamond is fast becoming a highly sought after biomaterial for electrical stimulation, however, its inherent surface roughness introduced by the growth process limits its applications in electronic circuitry. In this study, we introduce a fabrication method for developing conductive features in an insulating diamond substrate whilst maintaining a planar topography. Using a combination of microwave plasma enhanced chemical vapour deposition, inductively coupled plasma reactive ion etching, secondary diamond growth and silicon wet-etching, we have produced a patterned substrate in which the surface roughness at the interface between the conducting and insulating diamond is approximately 3nm. We also show that the patterned smooth topography is capable of neuronal cell adhesion and growth whilst restricting bacterial adhesion.

MicroRNA‐432 contributes to dopamine cocktail and retinoic acid induced differentiation of human neuroblastoma cells by targeting NESTIN and RCOR1 genes

MicroRNA (miRNA) regulates expression of protein coding genes and has been implicated in diverse cellular processes including neuronal differentiation, cell growth and death. To identify the role of miRNA in neuronal differentiation, SH-SY5Y and IMR-32 cells were treated with dopamine cocktail and retinoic acid to induce differentiation. Detection of miRNAs in differentiated cells revealed that expression of many miRNAs was altered significantly. Among the altered miRNAs, human brain expressed miR-432 induced neurite projections, arrested cells in G0-G1, reduced cell proliferation and could significantly repress NESTIN/NES, RCOR1/COREST and MECP2. Our results reveal that miR-432 regulate neuronal differentiation of human neuroblastoma cells.