Niina Onnela

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PURPOSE The production of functional retinal pigment epithelium (RPE) cells from human embryonic (hESCs) and human induced pluripotent stem cells (hiPSCs) in defined and xeno-free conditions is highly desirable, especially for their use in cell therapy for retinal diseases. In addition, differentiated RPE cells provide an individualized disease model and(More)
The development and differentiation of stem cell-derived impermeable retinal pigment epithelium (RPE) with tight junctions (TJs) is a gradual process that is, at confluence, controlled by cell-to-cell contact. The objective of this study was to evaluate the use of electric impedance spectroscopy (EIS) to follow the maturation and development of barrier(More)
The barrier properties of epithelium are conventionally defined by transepithelial resistance (TER). TER provides information about the tightness of the epithelium. Electrical impedance spectroscopy (EIS) provides additional information regarding cell membrane properties, such as changes in electric capacitance and possible parallel or serial pathways that(More)
Retinal implants may provide vision for people suffering from photoreceptor degeneration caused by different eye diseases. Electrode size in retinal implant should be decreased in order to increase the resolution provided by the implant. We defined electric properties of five different electrode materials (Au, Ir-b, Ti, TiN, Pt-b) widely used in retinal(More)
The purpose of this study is to develop and test a method to reveal if the retinal pigment epithelium (RPE) cells differentiated from human embryonic stem cells (hESC) support the functions of photoreceptors. hESC-derived RPE (hESC–RPE) cells offer a potent cell source for cell replacement therapy that may be used to prevent certain eye diseases. Methods to(More)
Polypyrrole (PPy) coated electrodes may provide new solutions to increase the charge injection capacity and biocompatibility of metal electrodes in e.g., neural stimulus applications. In this study, electrical impedance spectra of PPy coated platinum (Pt) electrodes having three different coating thicknesses were measured and modeled. A suitable equivalent(More)
This paper describes the creation of an anatomically detailed high resolution model of the human head based on the Visible Human Female data from the National Library of Medicine archives. Automatic and semi-automatic segmentation algorithms were applied over the 3 image volumes – CT, MRI and anatomical cryo-sections of the cadaver – to label a total of 23(More)
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