Nanofiber 3-D Cell Based Assays

This “News behind the News” is a historic event.  It demonstrates how nanofiber scaffolds can be used to engineer organs for human transplants. Good news for researchers looking solutions are in vivo like environments for cell based assays.

Nanofibers Solutions work in transplants-imagine how well they will work in your 3-D based cell based assays.

3-D Cell Based Assays for Drug Discovery are the future. Like any new model, adoption rates are a function of how well the new solutions works. “The proof is in the pudding”.

Here’re highlights of a historic event based on transplants using nanofiber engineered laryngotrachea : Collaboration between Nanofiber Solutions and the Karolinska Institutet produces first synthetic laryngotracheal implants seeded with the patient’s stem cells to be successfully transplanted into human patients in Russia.

COLUMBUS, Ohio, June 26, 2012 – Nanofiber Solutions, LLC, an Ohio-based developer, manufacturer and marketer of 3-D synthetic scaffolds to advance basic research, tissue engineering and regenerative medicine announced today the first and second successful transplants of its tissue engineered laryngotracheal implants seeded with cells from the patients’ bone marrow.

The surgeries were performed June 19th and 21st at the Krasnodar Regional Hospital (Russia) by Dr. Paolo Macchiarini, Professor of Regenerative Surgery at the Karolinska Institutet (Stockholm, Sweden), and colleagues. Dr. Macchiarini led an international team that included Dr. Vladimir Porhanov, head of Oncological and Thoracic Surgery at Kuban State Medical University (Russia), Dr. Jed Johnson, Nanofiber Solution’s Chief Technology Officer who created the synthetic organs, Harvard Bioscience (Boston, USA) who produced the bioreactor, and Dr. Alessandra Bianco at University of Rome, Tor Vergata, who performed mechanical testing during scaffold development.

Both patients, a 33 year-old mother from St. Petersburg and a 28 year-old man from Rostov-on-Don, were in au to accidents and suffered from a narrowing of the laryngotracheal junction for which they already had failed previous surgeries. Transplantation was the last option for the patients to have normal quality of life. Immediately following transplantation, both patients were able to speak and breathe normally.

Nanofiber Solutions, lead by Dr. Johnson, designed and built the nanofiber laryngotracheal scaffolds specifically to match the dimensions of each patient’s natural larynx and trachea, while Harvard Bioscience provided a bioreactor used to seed the scaffold with the patients’ own stem cells.  Although this procedure represents the world’s first and second successful use of synthetic synthetic laryngotracheal implants, it is Nanofiber Solution’s second and third successful organ implants using their synthetic scaffolds within the last year.

Nanofiber Solutions’ scaffolds mimic the body’s physical structure and allow for a more successful seeding, growth and differentiation of stem cells. Because the cells used to regenerate the larynx and trachea were the patients’ own, doctors report there has been no rejection of the transplants and the patients are not taking immunosuppressive drugs. (more).

Capabilities of 3-D nanofiber scaffolds for cell based assays:

Human brain tumor biopsy showing migrating tumor cells along the alligned nanofiber.
  • Nanofibers are optically transparent to allow for live-cell imaging and real time quantification of cell mobility using an inverted microscope
  • Nanofibers mimic the 3D topography found in vivo which produces a more realistic cellular response to therapeutics.
  • More realistic cellular behavior means you can use fewer animals and decrease time-to-market for drug discovery and development.
  • Nanofibers can easily be coated with ECM proteins using existing protocols for standard lab ware.
  • Cells can be easily removed for protein or gene analysis using trypsin, EDTA, etc.
  • We will continue posting relevant press releases, pubs and data that prove the capabilities of these important solutions.

    Jim Musick and Vitro Biopharma

    Coming Soon

    Neuromics recently added key products from Dr. Jim Musick and our friends @ Vitro Biopharma. These include potent umbilical cord derived human mesenchymal stem cells and MSCGroTM (best of breed growth and differentiation media). These cells are capable of many passages enabling researchers to build large stocks.

    MSCs_MSCGro

    We will be posting Jim’s profile in several weeks.

    Stem Cell and Cell Based Assays Groups on Linkedin

    I wanted to share some links to groups on Linkedin that have proven a useful resource for me. They are also additive to the stories and data posted here:

    Stem Cell Clinical TrialsStem Cell Clinical Trials

    Note: I am the moderator the the Stem Cell Clinical Trail group and welcome all new members. We are currently 400+ strong and growing.

    3D cell biology : tools & techniques3D cell biology : tools & techniques

    Stem Cell Research Stem Cell Research

    California Institute for Regenerative Medicine (CIRM)California Institute for Regenerative Medicine (CIRM)

    neuropathy and neuropathic painneuropathy and neuropathic pain

    The Gene Silencing Collaboration (RNAi, siRNA, miRNA, Dicer, etc.)The Gene Silencing Collaboration (RNAi, siRNA, miRNA, Dicer, etc.)

    Enjoy.

    Coming Soon-Dr. Gerry Shaw

    Zen and the Art of Bio-marker Production

    Up next will be Dr. Gerry Shaw.  Gerry is the founder and head of EnCor Biotechnology, Inc. His company is recognized for creating markers that are engines of Neuroscience and Stem Cell Research.

    Dr. Gerry Shaw with Triumph MC

    Dr. Gerry Shaw with Triumph MC

    I am pleased to represent his company’s reagents. They are well designed, thoroughly tested and proven to work in my customers’ many application.

    They have proven especially effective in working in cell based assays using our eSC derived hNP1 human neurons and e18 primary rat hippocampal neurons.

    Applications include the study of TBI, SCI, ALS, AD, MS and PD.

    Image:  hN2 cells stained with our chicken polyclonal antibody to Vimentin, in red. Islands of Hn2 cells form after 4 days in culture forming beautiful flower like structures. Vimentin is a well established marker of early differentiating neuronal lineage cells. Taken with a 10X objective lens. Blue staining is the nuclear DNA.

    hN2 Cells stained with Vimentin

    hN2 Cells stained with Vimentin

    Harnessing the Power of Neural Stem Cells

    I wanted to share an important presentation by Dr. Steve Stice. He is a featured researcher in “News Behind the Neuroscience News”.

    “Does amplification of neural progenitor cells derived from embryonic stem cells solve problems of cell production and FDA safety standards?”
    Steven L. Stice, PhD
    Professor, GRA Eminent Scholar
    Director of the Regenerative Bioscience Center at University of Georgia
    CSO, Aruna Biomedical Inc.

    Lectin Binding Profiles among Human Embryonic Stem Cells

    I have featured  numerous posting of innovations by Dr. Steve Stice and our friends at Aruna Biomedical. Here I would like to share a publication by Steve and his team featuring a new slant on isolating eSC Derived hNP Neural Progenitors. This study also includes methods for sorting hESCs, hNP cells and hMP cells.

    Mahesh C. Dodla, Amber Young, Alison Venable, Kowser Hasneen1, Raj R. Rao, David W. Machacek, Steven L. Stice. Differing Lectin Binding Profiles among Human Embryonic Stem Cells and Derivatives Aid in the Isolation of Neural Progenitor Cells. PLoS ONE 6(8): e23266. doi:10.1371/journal.pone.0023266.

    Abstract: Identification of cell lineage specific glycans can help in understanding their role in maintenance, proliferation and differentiation. Furthermore, these glycans can serve as markers for isolation of homogenous populations of cells. Using a panel of eight biotinylated lectins, the glycan expression of hESCs, hESCs-derived human neural progenitors (hNP) cells, and hESCs-derived mesenchymal progenitor (hMP) cells was investigated. Our goal was to identify glycans that are unique for hNP cells and use the corresponding lectins for cell isolation. Flow cytometry and immunocytochemistry were used to determine expression and localization of glycans, respectively, in each cell type. These results show that the glycan expression changes upon differentiation of hESCs and is different for neural and mesenchymal lineage. For example, binding of PHA-L lectin is low in hESCs (14±4.4%) but significantly higher in differentiated hNP cells (99±0.4%) and hMP cells (90±3%). Three lectins: VVA, DBA and LTL have low binding in hESCs and hMP cells, but significantly higher binding in hNP cells. Finally, VVA lectin binding was used to isolate hNP cells from a mixed population of hESCs, hNP cells and hMP cells. This is the first report that compares glycan expression across these human stem cell lineages and identifies significant differences. Also, this is the first study that uses VVA lectin for isolation for human neural progenitor cells.

    hNP1_STEM_CELL_MARKERS_IF_IHC

    Figure 1. Defining the stem cell phenotype using immunocytochemistry and flow cytometry.Phase contrast image of hESCs (A), hNPs (B), and hMPs (C). hESCs express pluripotency markers: Oct 4 (D,GG, JJ), SSEA-4 (G), and Sox 2 (J,GG); lack expression of Nestin (M, JJ), CD 166 (P,DD), CD73 (DD), and CD105 (AA). hNPs have low expression of pluripotency markers: Oct 4 (E,KK), SSEA-4 (H); and mesenchymal markers CD 166 (Q,EE), CD73 (EE), and CD105 (BB). hNPs express neural markers: Sox 2 (J,HH) and Nestin (N,HH,KK). hMPs lack expression of pluripotency markers: Oct 4 (F,LL), SSEA-4 (I), and Sox 2 (L,II); however, hMPs express Nestin (O,II,LL), CD 166 (R,FF), CD73 (FF), CD90 (CC) and CD105 (CC). All the cells have been stained with the nuclear marker DAPI (blue) in panels D- P. Scale bar: 10 µm. In the dot plots, red dots indicate isotype control or secondary antibody only; black dots indicate the antigen staining. doi:10.1371/journal.pone.0023266.g001

     By comparing hESCs, hNP cells and hMP cells, we have identified glycan structures that are unique to hNP cells: GalNac end groups (VVA), α-linked N-acetylgalactosamine (DBA), and fucose moieties α-linked to GlcNAc (LTL). Future studies help in identifying the roles of these glycans in cell maintenance, proliferation and differentiation fate.

    I will keep you posted on these future Studies.

    Differential healing properties of human ACL and MCL Stem Cells

    Autologous Stem Cell therapies for human injury and disease are gaining momentum. Understanding the properties of Stem Cell Colonies that have potential for these therapies is key to optimizing treatments. This study provides knowledge on the properties and their impact on future therapies for anterior cruciate ligament (hACL) and medial collateral ligament (hMCL) of the knee joint.

    Jianying Zhang, Tiffany Pan, Hee-Jeong Im, Freddie H Fu and James HC Wang. Differential properties of human ACL and MCL stem cells may be responsible for their differential healing capacity. Differential properties of human ACL and MCL stem cells may be responsible for their differential healing capacity. BMC Medicine 2011, 9:68doi:10.1186/1741-7015-9-68.

    Background: The human anterior cruciate ligament (hACL) and medial collateral ligament (hMCL) of the knee joint are frequently injured, especially in athletic settings. It has been known that, while injuries to the MCL typically heal with conservative treatment, ACL injuries usually do not heal. As adult stem cells repair injured tissues through proliferation and differentiation, we hypothesized that the hACL and hMCL contain stem cells exhibiting unique properties that could be responsible for the differential healing capacity of the two ligaments.

    Methods: To test the above hypothesis, we derived ligament stem cells from normal hACL and hMCL samples from the same adult donors using tissue culture techniques and characterized their properties using immunocytochemistry, RT-PCR, and flow cytometry.

    Self-renewal of hACL-SCs and hMCL-SCsImages:The expression of stem cell markers in hACL-SCs and hMCL-SCs. At passage 5, hACL-SCs had already become highly elongated in confluent culture, a typical fibroblast phenotype (A). In contrast, even at passage 13, confluent hMCL-SCs remained cobblestone-like (B). Moreover, hACL-SCs no longer expressed nucleostemin (C) or SSEA-4 (E) at passages > 5, whereas hMCL-SCs expressed both stem cell markers at passage 13 (D, F). Note, however, that hMCL-SCs at this high passage exhibited a lesser degree of nucleostemin expression compared to the cells at passage 1 (see Figure 3). The results shown here were obtained from a male donor of 27 years oldTo test the above hypothesis, we derived ligament stem cells from normal hACL and hMCL samples from the same adult donors using tissue culture techniques and characterized their properties using immunocytochemistry, RT-PCR, and flow cytometry.

     

    Results: We found that both hACL stem cells (hACL-SCs) and hMCL stem cells (hMCL-SCs) formed colonies in culture and expressed stem cell markers nucleostemin and stage-specific embryonic antigen-4 (SSEA-4). Moreover, both hACL-SCs and hMCL-SCs expressed CD surface markers for mesenchymal stem cells, including CD44 and CD90, but not those markers for vascular cells, CD31, CD34, CD45, and CD146. However, hACL-SCs differed from hMCL-SCs in that the size and number of hACL-SC colonies in culture were much smaller and grew more slowly than hMCL-SC colonies. Moreover, fewer hACL-SCs in cell colonies expressed stem cell markers STRO-1 and octamer-binding transcription factor-4 (Oct-4) than hMCL-SCs. Finally, hACL-SCs had less multi-differentiation potential than hMCL-SCs, evidenced by differing extents of adipogenesis, chondrogenesis, and osteogenesis in the respective induction media.

    Conclusions: This study shows for the first time that hACL-SCs are intrinsically different from hMCL-SCs. We suggest that the differences in their properties contribute to the known disparity in healing capabilities between the two ligaments.

    I will be posting more on autologous stem cell therapies research.

    More on STEMEZ hN2 Primary Human Neurons

    My company’s STEMEZTM hN2 Primary Human Neuron Discovery Kits have been a frequent topic on “News Behind the Neuroscience News”. My friends at Aruna Biomedical continue to broaden the capabilities of these Kits based on customer feedback.

    I am seeing increasing demand for these cells as these capabilities are published. Here’s the latest:

    A. Young, D.W. Machacek, S.K. Dhara, P.R. MacLeish, M. Benveniste, M.C. Dodla, C.D. Sturkie and S.L. Stice. Ion channels and ionotrophic receptors in a human embryonic stem cell derived neural progenitors. doi:10.1016/j.neuroscience.2011.04.039. Markers used:…mouse nonoclonal anti nestin (neuromics), mouse monoclonal anti tuj-1 (neuromics)…

    Abstract: Human neural progenitor cells differentiated from human embryonic stem cells offer a potential cell source for studying neurodegenerative diseases and for drug screening assays. Previously, we demonstrated that human neural progenitors could be maintained in a proliferative state with the addition of leukemia inhibitory factor and basic fibroblast growth factor. Here we demonstrate that 96 h after removal of basic fibroblast growth factor the neural progenitor cell culture was significantly altered and cell replication halted. Fourteen days after the removal of basic fibroblast growth factor, most cells expressed microtubule-associated protein 2 and TUJ1, markers characterizing a post-mitotic neuronal phenotype as well as neural developmental markers Cdh2 and Gbx2. Real-time PCR was performed to determine the ionotrophic receptor subunit expression profile. Differentiated neural progenitors express subunits of glutamatergic, GABAergic, nicotinic, purinergic and transient receptor potential receptors. In addition, sodium and calcium channel subunits were also expressed. Functionally, virtually all the hNP cells tested under whole-cell voltage clamp exhibited delayed rectifier potassium channel currents and some differentiated cells exhibited tetrodotoxin-sensitive, voltage-dependent sodium channel current. Action potentials could also be elicited by current injection under whole-cell current clamp in a minority of cells. These results indicate that removing basic fibroblast growth factor from the neural progenitor cell cultures leads to a post-mitotic state, and has the capability to produce excitable cells that can generate action potentials, a landmark characteristic of a neuronal phenotype. This is the first report of an efficient and simple means of generating human neuronal cells for ionotrophic receptor assays and ultimately for electrically active human neural cell assays for drug discovery.

    STEMEZ hN2 Cells-Electrophysiology Data

    STEMEZ hN2 Cells-Electrophysiology Data

     

     

     

     

     

    I will continue to post updates here.

    25 Best Blogs for Following Stem Cell Research

    Providing research proven and reasonably priced Stem Cell Research Reagents is core to our business growth.  Part of my business strategy includes keeping the Stem Cell research community up to date on latest news, methods and publications. This helps oil the engines of basic research and drug discovery.

    hN2 Cell-Differentiation

    Images Courtesy of Paula M. Keeney, Laboratory and Research Manager, VCU Parkinson's Disease Center of Excellence.

    This listing comes to me from my friend Roxanne McAnn at Nursingdegree.net.

    Stem cell research has been a contentious issue in both the scientific and political spheres for quite some years. Despite the ongoing battle between those who support and those who oppose the research and treatments, new discoveries and advances in the field are being made all the time. Whether you’re pursuing a career in medicine or science, if you’d like to keep up with these advances, then blogs on the issue are one of the best tools out there. Here, you’ll find a collection of blogs that provide all the information you’ll need to stay on top of the latest in stem cell discoveries.

    News-These blogs will let you stay on the cutting edge of new developments in the stem cell research community.

    1. The Stem Cell Blog: Through this blog, you’ll be able to get updates on the latest and greatest in stem cell research.
    2. Stem Cell News Blog: This blog collects a wide range of articles related to stem cell treatments, research and policy.
    3. Ben’s Stem Cell News: Ben Kaplan is a stem cell activist, blogger and a biotech professional who shares his thoughts and the latest information on stem cells here.
    4. Stem Cell Directory: No matter what kind of stem cell information you’re looking for, you’ll find it here through articles, news and videos.
    5. All Things Stem Cell: From treating baldness to cancer, learn about the myriad of ways stem cells may be able to help patients on this blog.
    6. Cell News: This blog will make it simple to be in-the-know when it comes to everything related to stem cells.
    7. The Stem Cell Trekker: Use this blog to learn more about stem cell innovations around the globe.
    8. StemSave: You might not think dental care when you think of stem cells, but this blog will show you that stem cells may be able to be taken from the teeth, giving you a whole new appreciation for those chompers.
    9. Joescamp’s Stem Cell Blog: This blog offers up news, information and insights into adult stem cell research.

    Businesses and Organizations-Check out these blogs to see what research corporations and organizations
    invested in stem cells are doing.

    1. International Stem Cell Corporation: Visit this blog to learn more about stem cell research that’s being done overseas, as many countries don’t have the same restrictions on research as the U.S.
    2. ViaCord Blog: This company, invested in cord blood baking and research, shares advances in the field of stem cells and cord blood treatments through this blog.
    3. Stem Cell Network Blog: Based out of Canada, this organization’s blog will help readers stay on top of new studies being done in the field, as well as some political issues that will affect researchers in Canada and around the world.
    4. Stem Cell Aware: Here you’ll find articles and information that can help you learn more about individuals who are receiving treatment with adult stem cells around the world.
    5. Umbilical Cord Blood Blog: Learn more about donating umbilical blood and the stem cell research being done with it through this organization’s blog.

    Commentary Here, you’ll get not only news, but commentary on stem cell issues as well.

    1. David Granovsky’s Stem Cell Blog: Ranked as one of the top health bloggers by Wellsphere, David Granovsky’s blog on stem cells is sure to provide you more  information on the subject than you’ll have time to read.
    2. California Stem Cell Report: See how stem cell politics are affecting research and development in California through this blog written by journalist David Jensen.
    3. Advance Stem Cell Research: Follow the latest news and commentary on stem cells with this blog.

    Research-These blogs, many from labs and experts in the field, focus on providing news and information on the best research being done with stem cells in the world.

    1. Knoepfler Lab Stem Cell Blog: The UC Davis School of Medicine maintains this blog, providing readers with information on everything stem cell as well as other science-related issues.
    2. CIRM Research Results: The California Institute for Regenerative Medicine shares their latest discoveries and political battles here.
    3. Robert Lanza, MD: Dr. Robert Lanza is a scientist and professor working on issues related to cell technology and engineering; his blog will provide readers with some insights into the field and his research.
    4. Stem Cell Gateway: Whether you live in the U.S. or abroad, this blog is the place to visit for information geared towards the stem cell research community.
    5. Tissue and Cellular Innovation Center Blog: Focused on tissue engineering and stem cell biology, this center is at the forefront of much of the research they share via this blog.
    6. Stem Cell Breaking Research: Need to know the absolute latest on stem cell research? This blog may be one of your best bets, with updates posted every day.
    7. Stem Cell Digest.net: On this blog, you’ll find information about stem cell research, progress, new applications and companies who are doing the work.
    8. Stem Cell Methods: Researchers, scientists and medical professionals can learn more about the protocols and methods being used in stem cell research and treatment through this blog.

    Author’s not (6/1/2011). This excellent site was brought to my attention by Dr. Anthony G. Payne- www.stemcelltherapies.org: This site is run by Steenblock Research Institute (San Clemente, California) which is a 501(c)(3) non-profit organization devoted to stem cell related education and research (SRI has a massive library facility and  stem cell R & D laboratory).

    Ion Channels and Neuromics’ STEMEZ Cells

    In my conversation with neuro-drug discover researchers, I am frequently being asked about the potential of using our STEMEZ(TM) hNP1 Human Neural Progenitors Expansion Kits for studying ion channels. How effective are these cells as a source for studying neurodegenerative diseases and for drug screening assays?  There is good news from Dr. Steve Stice and my friends from ArunA and UGA.

    When differentiated, these  neural progenitors express subunits of glutamatergic,  GABAergic, nicotinic, purinergic and transient receptor potential receptors. In addition, sodium  and calcium channel subunits were also expressed. Functionally, virtually all the NP cells exhibited delayed rectifier potassium channel currents and some differentiated cells exhibited  tetrodotoxin sensitive, voltage-dependent sodium channel current under whole-cell voltage clamp and action potentials could be elicited by current injection under whole-cell current clamp.  These results indicate that removing basic fibroblast growth factor from the neural progenitor cell cultures leads to a post-mitotic state, and also results in the capability to produce excitable cells that can generate action potentials. This is the first data demonstrating capabilitiesof these cells for ionotrophic receptor assays and ultimately for electrically active human neural cell assays for drug discovery.
    hNP1_Gene_Expression

    Images: Glutamate receptor expression in hNP cells and differentiated hNP cells The expression of ionotropic glutamate receptors might also be an indicator of neuronal maturation. These receptors are composed of three distinct families: NMDA, kainate and AMPA receptors. The hNP cells and differentiated hNP cells cultured in the absence of bFGF for 2 weeks were analyzed for mRNA expression of subunits of each glutamate receptor subtype relative to hESCs. Significant increases (p<0.05) in Grin2b were seen in hNP cells (20 fold) and differentiated hNP cells (25 fold) relative to hESCs (Figure 3A). Additionally, Grin1 and Grin2d were significantly increased (p<0.05) only in differentiated hNP cells relative to hESCs, but not in undifferentiated hNP cells (Figure 3A). Of the kainate receptors, Grik4 and Grik5 were significantly (p<0.05) increased only in undifferentiated hNP cells relative to hESCs (Figure 3B); whereas, Grik2 was significantly (p<0.05) increased only in hNP cells where bFGF had been removed (Figure 3B). AMPA receptor subunits were also examined. Gria1 and Gria4 were up regulated in hNP cells relative to hESCs (Figure 3C). Two week differentiated hNP cells showed significant (p<0.05) up regulation of Gria2 and Gira4 relative to hESCs (Figure 3C). To determine if functional glutamate channels exist in differentiated hNP cells, calcium influx in response to AMPA, kainic acid or NMDA application was measured on hNP cells, 14 days after the removal of bFGF. Figure 3G indicates that NMDA could not depolarize differentiated or undifferentiated hNP cells enough to cause significant calcium influx above background. In contrast, AMPA and kainic acid can cause calcium influx which can be potentiated by AMPA receptor specific modulator, cyclothiazide (50 μM, Figure 3G).Calcium influx was detected in the presence of cyclothiazide in calcium activity as measured (Figure 3H).

    hNP1_Electrophysiology

    Images: Sodium channel activity in differentiated hNP cells was measured using whole cell voltage clamp. 81 total hNP cells cultured in the absence of bFGF from 4 to 27 days were analyzed. Of these, 34 exhibited no fast inward currents in response to a step depolarization indicating the 348 absence of functional voltage gated sodium channels (Figure 4G). The remaining cells yielded between 0.04 – 1.5 nA of inward current in response to the step depolarization (Figures 4B and 4G). These currents inactivated rapidly in all cases (Figures 4B and 4C) and could be abolished with the addition of 1 μM TTX (n = 3 cells; Figure 4C). Voltage-dependent steady state inactivation (n = 11 cells; Figure 4D) and recovery from fast inactivation (n = 5 cells; Figure 4E) were also observed on several positive cells. A subset of these cells was subjected to current clamp and action potentials were elicited by current injection (n = 8 cells, Figure 4F). In support of this, increasing concentrations of a sodium channel activator veratridine in a FLIPR assay on differentiated hNP cells show an increasing calcium response (Figure 4H). This probably resulted from voltage-gated sodium channel depolarization of cells that subsequently allowed calcium influx through calcium channels. These data indicate that differentiation of hNP cells by removal of bFGF can lead to a neuronal cell that can generate action potentials and depolarize the cell. The 58% hit rate for voltage-gated sodium channel function (Figure 4G), does not reflect the true proportion of sodium channel positive cells in our differentiated hNP cells, but rather our ability to morphologically distinguish these cells from negative cells by eye. An example of the morphology of a sodium channel positive cell is shown in Figure 4A. The positive cells were phase bright with a few long processes.