Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany.
Key Laboratory of Microsystems and Microstructures Manufacturing, Ministry of Education, Harbin Institute of Technology, Yi Kuang Jie 2, Harbin 150080, China.
Sci Adv. 2018 Nov 2;4(11):eaat4388. doi: 10.1126/sciadv.aat4388. eCollection 2018 Nov.
The intravitreal delivery of therapeutic agents promises major benefits in the field of ocular medicine. Traditional delivery methods rely on the random, passive diffusion of molecules, which do not allow for the rapid delivery of a concentrated cargo to a defined region at the posterior pole of the eye. The use of particles promises targeted delivery but faces the challenge that most tissues including the vitreous have a tight macromolecular matrix that acts as a barrier and prevents its penetration. Here, we demonstrate novel intravitreal delivery microvehicles-slippery micropropellers-that can be actively propelled through the vitreous humor to reach the retina. The propulsion is achieved by helical magnetic micropropellers that have a liquid layer coating to minimize adhesion to the surrounding biopolymeric network. The submicrometer diameter of the propellers enables the penetration of the biopolymeric network and the propulsion through the porcine vitreous body of the eye over centimeter distances. Clinical optical coherence tomography is used to monitor the movement of the propellers and confirm their arrival on the retina near the optic disc. Overcoming the adhesion forces and actively navigating a swarm of micropropellers in the dense vitreous humor promise practical applications in ophthalmology.
眼内递送治疗剂在眼科学领域有很大的优势。传统的递送方法依赖于分子的随机、被动扩散，这使得无法快速将浓缩的货物递送到眼睛后极的一个确定区域。粒子的使用承诺了靶向递送，但面临着大多数组织（包括玻璃体）都有一个紧密的大分子基质作为屏障并阻止其穿透的挑战。在这里，我们展示了新型的眼内递送微载体——光滑的微推进器，可以主动地通过玻璃体腔到达视网膜。推进是通过具有液体层涂层的螺旋形磁性微推进器来实现的，以最小化与周围生物聚合物网络的附着力。推进器的亚微米直径使它能够穿透生物聚合物网络，并在厘米距离内穿过猪玻璃体进行推进。临床光学相干断层扫描用于监测推进器的运动，并确认它们在靠近视盘的视网膜上的到达。克服附着力并在密集的玻璃体腔中主动导航一群微推进器，有望在眼科学中有实际应用。
