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K.A. Kauper, P. Stabila, J. Mills, A. Lee, D. Litvak, J. Lydon, P. Heatherton, W. Tao; Delivery of Encapsulated Cell Technology (ECT) Device Implants Using a Small Gauge Needle . Invest. Ophthalmol. Vis. Sci. 2006;47(13):5118.
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Implantation of an ECT device currently requires a 2.0 mm sclerotomy and three sutures to close the incision site. Development of an ECT device that could be implanted through a small gauge needle would minimize surgical risk.
Micro ECT devices have been developed that are 200–fold smaller in overall displacement volume than those currently used in Neurotech clinical trials (0.03 µl compared to 6 µl). Microdevices were encapsulated with cells transfected to produce either ciliary neurotrophic factor (CTNF), interleukin–10 (IL–10) or pigment epithelial derived factor (PEDF). Delivery of micro–devices was tested through a 25–gauge needle with a modified syringe. Devices with conventional anchor loops to facilitate suture anchoring as well as modified anchor geometries using nitinol wire were investigated.
Microdevices produced 2.0 ± 0.5, 3.0 ± 0.7, and 39 ± 4 ng/device/day of CNTF, IL–10 and PEDF, respectively. Protein secretion from the micro ECT devices was consistent and stable over the course of several months with protein output to device volume levels 10 times greater than the capacity of the current clinical device. Microdevices were injected successfully via a 25–gauge needle and preliminary evaluations of anchoring methods indicate successful placement and constraint of the device.
Encapsulation using microdevices can provide therapeutic protein levels comparable to the current device configuration used in clinical trial evaluations of ECT. Surgical implant of a microdevice using a 25–gauge needle to inject the devices appear to be feasible and may offer a simpler, less invasive approach to encapsulation cell therapy in the eye.
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