Minamikawa Hajime, Att Wael, Ikeda Takayuki, Hirota Makoto, Ogawa Takahiro
Department of Molecular Cell Pharmacology, Graduate School of Dental Medicine, Hokkaido University, Sapporo 060-8586, Japan.
Laboratory for Bone and Implant Sciences (LBIS), The Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, UCLA School of Dentistry, Los Angeles, CA 90095-1668, USA.
Materials (Basel). 2016 Feb 6;9(2):102. doi: 10.3390/ma9020102.
Titanium undergoes time-dependent degradation in biological capability, or "biological aging". It is unknown whether the biological aging of titanium occurs beyond four weeks and whether age-related changes are definitely associated with surface hydrophilicity. We therefore measured multiple biological parameters of bone marrow-derived osteoblasts cultured on newly prepared, one-month-old, three-month-old, and six-month-old acid-etched titanium surfaces, as well as the hydrophilicity of these surfaces. New surfaces were superhydrophilic with a contact angle of ddH₂O of 0°, whereas old surfaces were all hydrophobic with the contact angle of around 90°. Cell attachment, cell spread, cell density, and alkaline phosphatase activity were highest on new surfaces and decreased in a time-dependent manner. These decreases persisted and remained significant for most of the biological parameters up to six-months. While the number of attached cells was negatively correlated with hydrophilicity, the other measured parameters were not. The biological capability of titanium continues to degrade up to six months of aging, but these effects are not directly associated with time-dependent reductions in hydrophilicity. A full understanding of the biological aging will help guide regulatory improvements in implant device manufacturing and develop countermeasures against this phenomenon in order to improve clinical outcomes.
钛会经历生物性能随时间的退化，即“生物老化”。目前尚不清楚钛的生物老化是否会超过四周，以及与年龄相关的变化是否肯定与表面亲水性有关。因此，我们测量了在新制备的、一个月、三个月和六个月大的酸蚀钛表面上培养的骨髓来源成骨细胞的多个生物学参数，以及这些表面的亲水性。新表面具有超亲水性，去离子水接触角为0°，而旧表面均为疏水性，接触角约为90°。细胞附着、细胞铺展、细胞密度和碱性磷酸酶活性在新表面上最高，并随时间呈下降趋势。这些下降在长达六个月的时间里持续存在，并且对于大多数生物学参数而言仍然显著。虽然附着细胞的数量与亲水性呈负相关，但其他测量参数并非如此。钛的生物性能在老化六个月内持续退化，但这些影响与亲水性随时间的降低并无直接关联。全面了解生物老化将有助于指导植入装置制造的监管改进，并制定应对这一现象的对策，以改善临床结果。
