Cheng L, Anglin E, Cunin F, Kim D, Sailor M J, Falkenstein I, Tammewar A, Freeman W R
Jacobs Retina Center at Shiley Eye Center, UCSD, 9415 Campus Point Drive, La Jolla, CA 92037-0946, USA.
Br J Ophthalmol. 2008 May;92(5):705-11. doi: 10.1136/bjo.2007.133587.
To determine the suitability of porous silicon photonic crystals for intraocular drug-delivery.
A rugate structure was electrochemically etched into a highly doped p-type silicon substrate to create a porous silicon film that was subsequently removed and ultrasonically fractured into particles. To stabilise the particles in aqueous media, the silicon particles were modified by surface alkylation (using thermal hydrosilylation) or by thermal oxidation. Unmodified particles, hydrosilylated particles and oxidised particles were injected into rabbit vitreous. The stability and toxicity of each type of particle were studied by indirect ophthalmoscopy, biomicroscopy, tonometry, electroretinography (ERG) and histology.
No toxicity was observed with any type of the particles during a period of >4 months. Surface alkylation led to dramatically increased intravitreal stability and slow degradation. The estimated vitreous half-life increased from 1 week (fresh particles) to 5 weeks (oxidised particles) and to 16 weeks (hydrosilylated particles).
The porous silicon photonic crystals showed good biocompatibility and may be used as an intraocular drug-delivery system. The intravitreal injectable porous silicon photonic crystals may be engineered to host a variety of therapeutics and achieve controlled drug release over long periods of time to treat chronic vitreoretinal diseases.
确定多孔硅光子晶体用于眼内给药的适用性。
通过电化学蚀刻在高掺杂p型硅衬底中形成一种叠层结构，以制备多孔硅膜，随后将其移除并超声破碎成颗粒。为了使颗粒在水性介质中稳定，通过表面烷基化（使用热硅氢化反应）或热氧化对硅颗粒进行改性。将未改性颗粒、硅氢化颗粒和氧化颗粒注入兔玻璃体。通过间接检眼镜检查、生物显微镜检查、眼压测量、视网膜电图（ERG）和组织学研究每种颗粒的稳定性和毒性。
在超过4个月的时间里，未观察到任何类型颗粒的毒性。表面烷基化导致玻璃体内稳定性显著提高和降解缓慢。估计的玻璃体半衰期从1周（新鲜颗粒）增加到5周（氧化颗粒）和16周（硅氢化颗粒）。
多孔硅光子晶体显示出良好的生物相容性，可作为眼内给药系统。可对玻璃体内可注射的多孔硅光子晶体进行设计，以承载多种治疗药物并实现长时间的控释，从而治疗慢性玻璃体视网膜疾病。
