Page 28 - eBook_Proceedings of the International Conference on Digital Manufacturing V1

Proceedings of the International Conference on Digital Manufacturing –
Volume 1

geometries like the Cube, limited pathways for mass transport
may hinder the outward diffusion of acidic oligomers and
monomers, allowing them to accumulate near the material surface
and induce a larger localised pH change.

Meanwhile, slender geometries, like the Dogbone, promote
faster fluid exchange and more uniform degradation, which
facilitates byproduct dispersion and results in greater overall
weight loss, but smaller local pH fluctuations.

These findings underscore the importance of considering
sample geometry, not just in terms of surface area or volume, but
as a factor that modulates the spatial distribution and temporal
evolution of degradation processes. For applications such as
bioresorbable scaffolds, where controlled degradation and
localised pH are critical for both mechanical performance and
biocompatibility, understanding this correlation offers valuable
guidance for design optimisation (Vaid, Yildirim, Pasquinelli &
King, 2021; Hussain et al., 2024).

Implications for Bone Scaffold Applications

The findings from this study offer meaningful insights for the
development and optimisation of PLA-based bone scaffolds.
Biodegradation behaviour, shaped by both material composition
and structural geometry, plays a crucial role in scaffold
performance, particularly in applications where degradation must
be synchronised with tissue regeneration.

Based on the degradation profiles observed over 28 days, the
weight loss of the samples remained below 0.4%, indicating a very
slow degradation rate in SBF. Specifically, an average weight loss
of approximately 0.349% was recorded over 28 days. Assuming a
simple linear degradation trend for initial estimation, complete
degradation would require approximately 8023 days, or about 22
years. However, it is well recognised that PLA degradation does
not proceed linearly; instead, it accelerates over time due to
autocatalysis induced by the accumulation of acidic byproducts.

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