Department of Pharmaceutics, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt.
Int J Pharm. 2013 Sep 15;454(1):249-58. doi: 10.1016/j.ijpharm.2013.06.067. Epub 2013 Jul 5.
Hypericin (HY) is a naturally-occurring, potent photosensitizer. However, its lipophilicity limits its therapeutic applications. Our attempt is, thus, to develop a biodegradable nanocarrier for hypericin capable of preserving its antibacterial photoactivity. Amphiphilic block copolymers were synthesized to prepare hypericin-laden nanoparticles (HY-NPs). The antimicrobial photoactivity of HY-NPs was assessed; in vitro against biofilm and planktonic cells of methicillin resistant Staphylococcus aureus (MRSA) clinical isolates and in vivo on infected wounds in rats. Nanoparticles of 45 nm in diameter ensured higher amounts of reactive oxygen species upon irradiation. HY-NPs demonstrated superior inhibition of biofilm over planktonic cells. In vivo wound healing studies in rats revealed faster healing, better epithelialization, keratinization and development of collagen fibers when HY-NPs were applied. Determination of growth factors and inflammatory mediators in the wound area confirmed superior healing potential of nanoencapsulated hypericin suggesting that hypericin can join the era of antibiotic-free antimicrobial therapy.
金丝桃素（HY）是一种天然存在的、有效的光敏剂。然而，其亲脂性限制了其治疗应用。因此，我们试图开发一种可生物降解的纳米载体，用于负载金丝桃素，以保持其抗菌光活性。我们合成了两亲性嵌段共聚物，以制备负载金丝桃素的纳米颗粒（HY-NPs）。评估了 HY-NPs 的抗菌光活性，包括体外对耐甲氧西林金黄色葡萄球菌（MRSA）临床分离株的生物膜和浮游细胞的作用，以及体内对感染伤口的作用。直径为 45nm 的纳米颗粒在照射时能产生更多的活性氧。HY-NPs 对生物膜的抑制作用优于浮游细胞。体内大鼠伤口愈合研究表明，当应用 HY-NPs 时，伤口愈合更快，上皮化、角化和胶原纤维发育更好。对伤口区域生长因子和炎症介质的测定证实，纳米囊封金丝桃素具有更好的愈合潜力，这表明金丝桃素可以加入无抗生素的抗菌治疗时代。
