Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

Many retinal gene therapy clinical trials require subretinal injections of small volumes of adeno-associated viral (AAV) vector solutions in patients with retinal dystrophies, using equipment not specifically designed for this purpose. We therefore evaluated an optimized injection system in order to identify variables that might influence the rate of injection and final dose of vector delivered. An optimized injection system was assembled with a 41G polytetrafluoroethylene tip for retinal gene therapy. Flow rate was recorded at relevant infusion pressures (2-22 psi [14-152 kPa]), different target pressures (0.02-30 mm Hg [0.003-4 kPa]) and temperatures (18°C vs. 36°C) using a semiautomated Accurus(®) Surgical System. Retention of AAV2/8 and AAV2/8(Y733F) vector was quantified after simulating loading/injection with or without 0.001% Pluronic(®) F-68 (PF-68). The optimized injection system provided a linear flow rate (μl/s)-to-infusion pressure (psi) relationship (y = 0.62x; r(2) = 0.99), independent of temperature and pressure changes relevant for intraocular surgery (18-36°C, 0.02-30 mm Hg). Differences in length of 41G polytetrafluoroethylene tips caused significant variation in flow rate (p < 0.001). Use of PF-68 significantly (p < 0.001) reduced loss of vector genomes in the injection system by 55% (AAV2/8) and 52% (AAV2/8(Y733F)). A customized subretinal injection system assembled using equipment currently available in the operating room can deliver a controlled volume of vector at a fixed rate across a range of possible clinical parameters encountered in vitreoretinal surgery. The inclusion of 0.001% PF-68 had a significant effect on the final dose of vector genomes delivered. The described technique is currently used successfully in a clinical trial.


Journal article


Human gene therapy methods

Publication Date





150 - 158


3 University Eye Hospital , Centre for Ophthalmology, Tübingen, Germany.