Abstract：
In this study, we evaluated the drug release behavior of diameter customized TiO2 nanotube layers fabricated by anodization with various applied voltage sequences: conventional constant applied potentials of 20 V (45 nm) and 60 V (80 nm), a 20/60 V stepped potential (50 nm [two-diameter]), and a 20-60 V swept potential (49 nm [full-tapered]) (values in parentheses indicate the inner tube diameter at the top part of nanotube layers). The structures of the 50 nm (two-diameter) and 49 nm (full-tapered) samples had smaller inner diameters at the top part of nanotube layers than that of the 80 nm sample, while the outer diameters at the bottom part of nanotube layers were almost the same size as the 80 nm sample. The 80 nm sample, which had the largest nanotube diameter and length, exhibited the greatest burst release, followed by the 50 nm (two-diameter), 49 nm (full-tapered), and 45 nm samples. The initial burst released drug amounts and release rates from the 50 nm (two-diameter) and 49 nm (full-tapered) samples were significantly suppressed by the smaller tube top. On the other hand, the largest proportion of the slow released drug amount to the total released drug amount was observed for the 50 nm (two-diameter) sample. Thus, 50 nm (two-diameter) achieved suppressed initial burst release and large storage capacity. Therefore, this study has, for the first time, applied TiO2 nanotube layers with modulated diameters (two-diameter and full-tapered) to the realization of a localized drug delivery system (LDDS) with customized drug release properties.
摘要：
在这项研究中,我们评估了通过各种施加电压序列通过阳极氧化制造的直径定制的TiO2纳米管层的药物释放行为：常规的恒定施加电位为20V（45nm）和60V（80nm），20/60V步进电位（50nm[两个直径]），和20-60V扫描电位(49nm[全锥形])(括号中的值表示纳米管层顶部的内管直径)。50nm（两个直径）和49nm（全锥形）样品的结构在纳米管层顶部的内径小于80nm样品的内径，而纳米管层底部的外径与80nm样品的尺寸几乎相同。80nm的样品，具有最大的纳米管直径和长度，展示了最大的爆发释放，其次是50nm（两个直径），49nm（全锥形），和45nm样品。较小的管顶部显著抑制了从50nm(两个直径)和49nm(全锥形)样品的初始突释药物量和释放速率。另一方面,对于50nm（两个直径）样品，观察到缓慢释放的药物量占总释放药物量的最大比例。因此，50nm（两个直径）实现了抑制的初始爆发释放和大的存储容量。因此,这项研究，第一次,应用具有调制直径(两个直径和全锥形)的TiO2纳米管层以实现具有定制药物释放特性的局部药物递送系统(LDDS)。
