San Jacinto Garcia Jorge, Sanz Del Olmo Natalia, Hutchinson Daniel J, Malkoch Michael
Royal Institute of Technology, School of Chemical Science and Engineering, Department of Fibre and Polymer Technology, KTH, Teknikringen 56-58, 100 44 Stockholm, Sweden.
ACS Appl Mater Interfaces. 2024 Jul 31;16(30):40056-40068. doi: 10.1021/acsami.4c09626. Epub 2024 Jul 20.
Open reduction internal fixation metal plates and screws remain the established standard-of-care for complex fracture fixation. They, however, have drawbacks such as limited customization, soft-tissue adhesions, and a lack of degradation. Bone cements and composites are being developed as alternative fixation techniques in order to overcome these issues. One such composite is a strong, stiff, and shapeable hydroxyapatite-containing material consisting of 1,3,5-triazine-2,4,6-trione (TATO) monomers, which cures through high energy visible light-induced thiol-ene coupling (TEC) chemistry. Previous human cadaver and in vivo studies have shown that patches of this composite provide sufficient fixation for healing bone fractures; however, the composite lacks degradability. To promote degradation through hydrolysis, new allyl-functionalized isosorbide-based polycarbonates have been added into the composite formulation, and their impact has been evaluated. Three polycarbonates with allyl functionalities, located at the termini (aPC1 and aPC2) or in the backbone (aPC3), were synthesized. Composites containing 1, 3, and 5 wt % of aPCs 1-3 were formulated and evaluated with regard to mechanical properties, water absorption, hydrolytic degradation, and cytotoxicity. Allyl-functionalized polycaprolactone (aPCL) was synthesized and used as a comparison. When integrated into the composite, aPC3 significantly impacted the material's properties, with the 5 wt % aPC3 formulation showing a significant increase in degradation of 469%, relative to the formulation not containing any aPCs after 8 weeks' immersion in PBS, along with a modest decrease in modulus of 28% to 4.01 (0.3) GPa. Osteosyntheses combining the aPC3 3 and 5 wt % formulations with screws on synthetic bones with ostectomies matched or outperformed the ones made with the previously studied neat composite with regard to bending stiffness and strength in four-point monotonic bending before and after immersion in PBS. The favorable mechanical properties, increased degradation, and nontoxic characteristics of the materials present aPC3 as a promising additive for the TATO composite formulations. This combination resulted in stiff composites with long-term degradation that are suitable for bone fracture repair.
切开复位内固定金属板和螺钉仍然是复杂骨折固定的既定标准治疗方法。然而，它们存在一些缺点，如定制性有限、软组织粘连和缺乏降解性。骨水泥和复合材料正在作为替代固定技术进行开发，以克服这些问题。一种这样的复合材料是一种由1,3,5-三嗪-2,4,6-三酮（TATO）单体组成的坚固、坚硬且可成型的含羟基磷灰石材料，它通过高能可见光诱导的硫醇-烯偶联（TEC）化学固化。先前的人体尸体和体内研究表明，这种复合材料的贴片为愈合骨折提供了足够的固定；然而，该复合材料缺乏降解性。为了通过水解促进降解，已将新的烯丙基官能化异山梨醇基聚碳酸酯添加到复合材料配方中，并评估了它们的影响。合成了三种烯丙基官能团位于末端（aPC1和aPC2）或主链（aPC3）的聚碳酸酯。配制了含有1、3和5 wt%的aPCs 1-3的复合材料，并对其机械性能、吸水性、水解降解和细胞毒性进行了评估。合成了烯丙基官能化聚己内酯（aPCL）并用作对照。当整合到复合材料中时，aPC3对材料性能有显著影响，5 wt% aPC3配方在PBS中浸泡8周后，相对于不含任何aPCs的配方，降解显著增加469%，同时模量适度下降28%至4.01（0.3）GPa。将aPC3 3 wt%和5 wt%配方与螺钉结合用于有截骨术的合成骨上的骨合成，在浸入PBS前后的四点单调弯曲中，其弯曲刚度和强度与先前研究的纯复合材料相比匹配或更优。材料的良好机械性能、增加的降解性和无毒特性表明aPC3是TATO复合材料配方的一种有前途的添加剂。这种组合产生了具有长期降解性的坚硬复合材料，适用于骨折修复。
