전기방사법으로 제조된 골 조직 공학용 폴리락트산-옥타칼슘인산염(PLA–OCP) 나노섬유 매트의 특성 = Characteristics of polylactic acid–octacalcium phosphate (PLA–OCP) nanofiber mats fabricated by electrospinning for bone tissue engineering

다국어 초록 (Multilingual Abstract)

Bone Tissue Engineering (BTE) integrates biology, materials science, and engineering to fabricate scaffolds that facilitate bone regeneration, offering a highly promising alternative to traditional bone grafting. Polylactic acid (PLA) is widely used due to its biodegradability and biocompatibility, but its low hydrophilicity and bioactivity limit its application. Octacalcium phosphate (OCP), a key precursor of hydroxyapatite (HA), has shown strong potential in enhancing the osteoconductivity of polymer-based scaffolds. Therefore, this study focused on fabricating electrospun PLA/OCP nanofiber mats and systematically evaluating their morphological, physicochemical, bioactivity, and cytocompatibility properties to determine their suitability for BTE applications.
Nanofiber mats were fabricated by electrospinning (flow rate 1 μL/min, 20 kV, 15 cm gap) by mixing ultrasonically dispersed OCP (PLA:OCP = 90:10, w/w) into a PLA solution (acetone/N,N-dimethylformamide, 80:20, v/v; 10, 12.5, 15%). Morphological and physicochemical characterization, degradation, and mechanical evaluation were performed. Additionally, mineralization behavior in Hanks' balanced salt solution (HBSS) was evaluated, and cytocompatibility and cytotoxicity were assessed using WST analysis and confocal microscopy.
The PLA/OCP nanofiber mat exhibited a uniform fiber structure and enhanced hydrophilicity and bioactivity. FTIR and XRD analyses confirmed the successful incorporation of OCP. DSC and mechanical test results shows that the thermal stability of the nanofiber mat is improved after the addition of OCP, but the tensile strength is slightly reduced. HA layers were formed on the nanofiber mats immersed in HBSS, exhibiting a consistent degradation rate and stable pH. WST analysis and confocal microscopy results confirmed excellent cell proliferation without cytotoxicity, while ALP activity further indicates enhanced osteogenic differentiation over time.
In conclusion, the incorporation of OCP significantly enhances the hydrophilicity, bioactivity, and degradation stability of PLA nanofiber mats while maintaining appropriate mechanical properties. These findings suggest that electrospun PLA/OCP nanofiber mats effectively enhance osteogenic potential.

목차 (Table of Contents)

• Contents
• Abstract(English) III
• 1. Introduction 1
• 2. Materials and Methods 4
• 2.1. Materials 4
• 2.2. Synthesis of OCP 4
• 2.3. Preparation of nanofibrous mats 5
• 2.3.1. Preparation of electrospinning solution 5
• 2.3.2. Electrospinning process 6
• 2.4. Characterization of nanofiber mats 6
• 2.4.1. Scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDX) analysis 6
• 2.4.2. Contact angle 7
• 2.4.3. Fourier transform infrared spectroscopy (FTIR) 7
• 2.4.4. X-ray diffraction (XRD) 7
• 2.4.5. Differential scanning calorimetry analysis (DSC) 8
• 2.5. Mechanical property tests 8
• 2.6. Mineralization of nanofiber mats 8
• 2.7. Degradation test 9
• 2.8. In vitro 10
• 2.8.1. Preparation of liquid extracts of material 10
• 2.8.2. Cell seeding 10
• 2.8.3. Cell viability analysis 10
• 2.8.4. Live/Dead cell analysis 11
• 2.8.5. Alkaline phosphatase activity 12
• 2.9. Statistical analysis 12
• 3. Results 13
• 3.1. Morphological observation of PLA and PLA/OCP nanofiber mats 13
• 3.2. Contact angle of PLA and PLA/OCP nanofiber mats 17
• 3.3. Chemical composition of PLA and PLA/OCP nanofiber mats 18
• 3.4. DSC analysis of PLA and PLA/OCP nanofiber mats 20
• 3.5. Mechanical property tests 20
• 3.6. Mineralization ability evaluation of PLA and PLA/OCP nanofiber mats 22
• 3.7. Degradation test 25
• 3.8. In vitro test 27
• 4. Discussion 32
• 5. Conclusion 41
• 6. References 43
• Abstract (Korean) 49