Alexander Butterwick

Learn More
Retinal stimulation with high spatial resolution requires close proximity of electrodes to target cells. This study examines the effects of material coatings and 3-dimensional geometries of subretinal prostheses on their integration with the retina. A trans-scleral implantation technique was developed to place microfabricated structures in the subretinal(More)
The design of high-resolution retinal prostheses presents many unique engineering and biological challenges. Ever smaller electrodes must inject enough charge to stimulate nerve cells, within electrochemically safe voltage limits. Stimulation sites should be placed within an electrode diameter from the target cells to prevent 'blurring' and minimize(More)
Repeated pulsed electrical stimulation is used in a multitude of neural interfaces; damage resulting from such stimulation was studied as a function of pulse duration, electrode size, and number of pulses using a fluorescent assay on chick chorioallontoic membrane (CAM) in vivo and chick retina in vitro. Data from the chick model were verified by repeating(More)
PURPOSE Nonviral gene therapy represents a promising treatment for retinal diseases, given clinically acceptable methods for efficient gene transfer. Electroporation is widely used for transfection, but causes significant collateral damage and a high rate of cell death, especially in applications in situ. This study was conducted in the interest of(More)
Electronic retinal prostheses represent a potentially effective approach for restoring some degree of sight in blind patients with retinal degeneration. However, levels of safe electrical stimulation and the underlying mechanisms of cellular damage are largely unknown. We measured the threshold of cellular damage as a function of pulse duration, electrode(More)
A major obstacle in applying gene therapy to clinical practice is the lack of efficient and safe gene delivery techniques. Viral delivery has encountered a number of serious problems including immunological reactions and malignancy. Non-viral delivery methods (liposomes, sonoporation and electroporation) have either low efficiency invivo or produce severe(More)
  • 1