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Synthesis of Graphene-Hydroxyapatite Nanocomposites for Potential Use in Bone Tissue Engineering
Published on: July 27, 2022
Poly (D,L-lactide)/nano-hydroxyapatite composite scaffolds for bone tissue engineering and biocompatibility
Jie Ren1, Peng Zhao, Tianbin Ren
1Institute of Nano and Bio-Polymeric Materials, School of Material Science and Engineering, Tongji University, Shanghai, 200092, P.R. China. renjie6598@163.com
This study explored a new way to make bone scaffolds using a biodegradable polymer and nano-hydroxyapatite. Traditional methods often use harmful solvents, so the researchers developed a solvent-free approach using supercritical CO2 and salt leaching. The resulting scaffolds had good mechanical strength and were porous enough for cells to grow. Tests showed the scaffolds were safe and supported tissue growth with only mild inflammation. The method avoids toxic solvents and could be useful for bone tissue engineering.
Area of Science:
- Biomaterials in regenerative medicine
- Polymer chemistry for tissue engineering
- Biocompatibility testing in biomedical research
Background:
Conventional ceramic bone substitutes face challenges like brittleness and poor moldability. These issues limit their utility in clinical settings. Polymer/bioceramic composites offer a potential solution by combining mechanical strength with biocompatibility. However, traditional fabrication methods often involve harmful organic solvents. These solvents may compromise cell viability or tissue integration. The use of solvent casting and particulate leaching is common but not ideal for medical applications. Researchers have sought alternative methods to avoid solvent-related risks. A need exists for scaffold fabrication that is both effective and safe for biological systems. This gap motivated the development of solvent-free composite fabrication techniques.
Purpose Of The Study:
This study aimed to develop a solvent-free method for creating polymer/bioceramic composite scaffolds. The goal was to enhance biocompatibility while maintaining structural integrity. The researchers focused on using Poly (D,L-lactide) and nano-hydroxyapatite as the base materials. These materials are known for their biodegradable and osteoconductive properties. The study introduced a novel fabrication technique using supercritical CO2 and salt leaching. This method avoids the use of harmful organic solvents. The researchers also evaluated the mechanical and structural properties of the scaffolds. The ultimate objective was to assess the biocompatibility of the resulting composite scaffolds.
Main Methods:
The researchers prepared PDLLA/NHA composites using in-situ polymerization. They then fabricated scaffolds using the supercritical CO2/salt-leaching method. This process involved dissolving salt particles in the polymer matrix. After polymerization, the salt was leached out to create pores. The scaffolds were analyzed using scanning electron microscopy and transmission electron microscopy. Gel permeation chromatography was used to assess molecular weight changes. The pore size and morphology were controlled by adjusting the SC CO2/SL parameters. The resulting scaffolds were tested for water absorption and compressive strength.
Main Results:
The molecular weight of the composites decreased as the NHA content increased. However, water absorption and compressive strength improved significantly. SEM images revealed that pore sizes of approximately 250 micrometers were achieved. The scaffolds showed no signs of cytotoxicity in in vitro tests. The cell relative growth rate and direct contact methods confirmed grade I biocompatibility. In vivo tests showed no acute systemic toxicity or mortality. Histological analysis after 1 and 9 weeks showed mild inflammation. The scaffolds maintained structural integrity and supported tissue integration.
Conclusions:
The study demonstrated that PDLLA/NHA composites can be fabricated without harmful solvents. The SC CO2/SL method produced scaffolds with desirable porosity and mechanical properties. The biocompatibility tests confirmed the safety of the scaffolds for biological applications. The researchers observed mild inflammation but no severe adverse effects. The results suggest that these scaffolds are suitable for bone tissue engineering. The method's solvent-free nature enhances its potential for clinical use. The findings support further investigation into the long-term performance of these scaffolds. The authors propose that this approach can be adapted for other tissue engineering applications.
Frequently Asked Questions
The scaffolds showed grade I biocompatibility and improved mechanical properties with pore sizes of about 250 micrometers.
The supercritical CO2/salt-leaching method was used to create porous scaffolds without organic solvents.
Pore size affects cell infiltration and nutrient transport, with 250 micrometers being optimal for tissue integration.
GPC was used to measure molecular weight changes in composites as NHA content increased.
No acute systemic toxicity or mortality was observed in the in vivo tests.
Mild inflammation was observed at 1 and 9 weeks, but no severe adverse effects were noted.
