聚乙二醇-聚己內酯混摻氫氧基磷灰石複合支架設計與機械性質之關聯研究

利用熱擠製形式的快速原型系統進行骨組織工程支架的列印已是目前的研究趨勢，這些系統又稱為三維列印，然而支架的孔洞結構必須能夠讓骨組織內的細胞具有足夠空間進行貼附與增生，其機械強度也應該接近植入部位以避免應力遮蔽效應。本研究使用可吸收高分子與生物相容性高的氫氧基磷灰石作為列印原料。本研究以不同分子量(10K及20K)的聚乙二醇-聚己內酯與混摻氫氧機磷灰石，比例為70:30，以正交結構、蜂巢結構及多邊形結構列印多孔隙支架。合成聚乙二醇-聚己內酯後以質子核磁共振光譜儀與傅立葉轉換紅外線光譜儀鑑定其分子結構，以視差掃描卡計分析高分子的熔點，分子量則以凝膠滲透層析儀測量。實驗結果發現，理論分子量在10K Da、12K Da、15K Da及20K Da的高分子經質子核磁共振光譜儀測量確認在化學位移2.2、1.6、1.3、4 ppm具有己內酯的訊號及在3.64 ppm發現乙二醇訊號。以傅立葉轉換紅外線光譜儀在波數1725.01 cm-1觀察到C=O訊號及在波數2946.7 cm-1觀察到CH2O-的訊號，因此可以確定合成高分子的分子結構。高分子的熔點分別是55.76, 56.96 oC，GPC測得分子量結果則為14405及29772 Da。在機械性質方面，正交結構的支架之最高抗壓應力在分子量20K Da下分別為4.4±"0.7 " MPa、6.7±"1.4 " MPa、17.5±"0.7 " MPa、16.4±"5.6 " MPa，蜂巢狀支架的最高抗壓應力在分子量20K Da下分別是5.7±1.3 MPa、12.5±1.8 MPa、9.8±2.0 MPa、15.4±1.4 MPa，多邊形結構支架的最高抗壓應力在分子量20k Da下分別是5.9±1.8 MPa、6.4±1.2 MPa、12.6±1.0 MPa、13.1±1.8 MPa，由此可見緻密度60%的交織結構具有最佳的抗壓強度。分子量為20k Da的聚己內酯材料抗壓強度較10k Da高。此外實驗結果顯示除了交織60%及蜂巢60%之外，支架隨著體積緻密程度增加抗壓強度增加，而三種結構中以交織結構抗壓強度最高。預期能作為退化性關節炎治療中提供骨組織修復支架的設計參考。

關鍵字

軟骨；組織工程支架；抗壓強度；三維列印；聚己內酯

並列摘要

Utilizing hot extrusion rapid prototyping to print the bone scaffold gives priority to developing the technique called 3-dimensional printing. However, the pore structure of the scaffold should be able to provide enough space for cell adhesion and differentiation. To avoid the stress shielding effect of the scaffold, the mechanical property should meet the implantation site. In this study, a bio-absorbable material blended with a biocompatible material – hydroxyapatite - was used to print the scaffold. We used varying molecular weights (9450, 20K) of Methoxy Poly(ethylene glycol-block-ε-caprolactone) mixed with hydroxyapatite with a ratio of 70:30. It is also used to prepare three kinds of pore structures (cross, honeycomb and line). Proton nuclear magnetic resonance (1H NMR) results show that 2.2, 1.6, 1.3, 4 ppm have a chemical shift forε-caprolactone and 3.64 ppm for ethylene glycol. Fourier transform infrared spectroscopy indicate a C=O and CH2O- peak at 1725.01 cm-1 and 2946.7 cm-1. The melting point of the material (55.76, 57.09, 56.65, 56.96 ̊C) increases as the molecular weight increases. The mechanical test shows an Ultimate Compressive Strength (UCS) of 4.4±"0.7 " MPa、6.7±"1.4 " MPa、17.5±"0.7 " MPa、16.4±"5.6 " MPa for cross structure, 5.7±1.3 MPa、12.5±1.8 MPa、9.8±2.0 MPa、15.4±1.4 MPa for honeycomb structure and 5.9±1.8 MPa、6.4±1.2 MPa、12.6±1.0 MPa、13.1±1.8 MPa for line structure. The study revealed that 60% cross structure has the best mechanical properties while Polycaprolactone with 20k molecular weight has the highest UCS. The results also show that the mechanical strength increases when the scaffold density increases and when the cross structure has the highest compressive strength. It can provide the reference for the bone scaffold designing.

並列關鍵字

Cartilage ； Tissue engineering scaffold ； Compressive strength ； three dimensional printing ； Polycaprolactone

參考文獻

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聚乙二醇-聚己內酯混摻氫氧基磷灰石複合支架設計與機械性質之關聯研究

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