
Studying the Effect of Dynamic Flow Fluctuations on the Biodegradability of PLA Scaffolds Designed for Bone Repair
Elnaz Abedini 1 © ℗
Abstract
Biodegradable scaffolds, which offer temporary structural support while encouraging natural tissue growth, are extremely important in bone tissue engineering. Because of its outstanding biocompatibility, adjustable degradation rate, and good mechanical characteristics, poly lactic acid (PLA) has become a top biomaterial. Most of the current biodegradation research, however, is carried out under static laboratory settings that fall short of reproducing the dynamic physiologic environment wherein scaffolds will actually be active in vivo . Complex fluid dynamics presented by the human body include blood flow, interstitial fluid movement, and mechanical loading that can greatly affect the behavior of scaffold breakdown. The biodegradation properties of 3D-printed PLA scaffolds created especially for bone tissue engineering uses are to be examined in this study in relation to dynamic flow oscillations.Fused deposition modeling (FDM) 3D printing technology was used to make PLA scaffolds with adjusted architectural characteristics of 65% porosity, interconnected pore sizes from 300 to 500 µm, and a strut thickness of 400 µm. Forty-five scaffold samples were split into three experimental groups (n=15 each): static flow control, low-frequency dynamic flow (0.5 Hz), and high-frequency dynamic flow (2.0 Hz). Over a 16-week period, biodegradation testing was carried out in a custom-made bioreactor system utilizing phosphate-buffered saline (PBS) at physiologic pH (7.4) and temperature (37°C) [1]. One-way ANOVA with post-hoc Tukey's test (p0.05) was used for statistical analysis; gravimetric analysis for mass loss detection; scanning electron microscopy (SEM) for surface morphology assessment; Fourier-transform infrared spectroscopy (FTIR) for chemical composition alterations; differential scanning calorimetry (DSC) for thermal property evaluation; and mechanical compression testing for structural integrity assessment. Dynamic flow circumstances were produced by a peristaltic pump system to mimic physiologic shear stress [5].Compared with static conditions, dynamic flow conditions substantially sped PLA scaffold decomposition. High-frequency dynamic flow produced 34.2 ± 4.1% mass loss after 16 weeks, whereas low-frequency dynamic flow yielded 22.7 ± 3.3% and static conditions 15.8 ± 2.9% (p0.001). Dynamic flow groups showed improved surface erosion, increased porosity, and earlier start of structural changes according to SEM analysis. Dynamic conditions FTIR spectroscopy confirmed accelerated hydrolytic cleavage of ester bonds. Mechanical testing revealed gradual drop in compressive strength; dynamic samples displayed 45–60% more strength loss than static controls. DSC analysis suggested lower crystallinity in dynamically tested scaffolds, implying increased polymer chain mobility and degradation sensitivity.Dynamic flow changes clearly affect PLA scaffold biodegradation mechanisms and kinetics. The enhanced degradation under dynamic conditions can be explained by mechanical stress-induced chain scission, increased mass transport, and better hydrolytic access to polymer chains. These results highlight how crucial it is to include physiologically relevant dynamic testing circumstances in scaffold evaluation methods in order to better forecast in vivo performance and maximize scaffold design for applications in bone tissue engineering.
Keywords: Biodegradable Scaffolds, Dynamic Flow Conditions, Polylactic Acid (PLA) , Bone