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International Journal of Bioprinting Collagen hydrolysate-loaded ODMA/PEGDMA scaffold

absorption value (relative to previous research) is likely due 10% ODMA within a PEGDMA matrix, highlighting
to the synthesis and crystallization processes, which affect the distinct mechanical responses of the two materials
the glass transition temperature (T ). Typically, crystalline under compressive stress. Pure PEGDMA exhibits a
g
polymers have a higher T than the same polymer in an linear increase in strain, reaching up to approximately
g
amorphous state because crystals have a more ordered 20%, indicating elastic behavior before undergoing plastic
structure. Therefore, this study may have achieved less deformation as the curve steepens. In contrast, the ODMA/
ordered crystallization than previous work, with more PEGDMA composite demonstrates significantly better
amorphous polymers of the same type. This would result compression resistance throughout the stress test period,
in a lower melting temperature, making the material easier with a consistent slope indicating increased hardness. The
to prepare before use. This result also demonstrates the composite’s initial strength is superior to pure PEGDMA
need for high energy to break the material’s structure, and exhibits higher compression stress compared to
and the maximum heat absorption value demonstrates previous research using pure GelMA and ODMA-GelMA
the material’s durability. This characteristic becomes even as cell scaffolds, which reported compression stresses of
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more significant when considering its application in the approximately 0.5 and 2.375 MPa, respectively. However,
body, as cartilage repair or replacement methods often the ODMA–PEGDMA composite has a lower strain value
involve long-term implantation of materials. due to the hard but brittle nature of PEGDMA, causing
easier deformation. The incorporation of ODMA effectively
3.2. Printability of ODMA–PEGDMA resin with DLP strengthens the matrix, making ODMA/PEGDMA an ideal
printer and morphology of the scaffold material for applications with high structural demands,
The 3D-printed scaffolds using PEGDMA resin mixed such as the development of scaffolds that must withstand
with various concentrations of ODMA (0.625%, 1.25%, physiological stress. The observed mechanical properties
2.5%, 5%, and 10% w/v) revealed that the resin with suggest that the addition of ODMA enhances the rigidity
0.625% ODMA exhibited the least formability, achieving of the PEGDMA structure, potentially increasing the
only 75% printing accuracy (Figure 7). In contrast, resins concentration of intermolecular connections and the
with higher ODMA concentrations demonstrated equally crosslinking density upon copolymerization, which is
effective printability (approximately 90%) when using DLP crucial for durable mechanical stability. 23,24 This enhanced
3D printing techniques. mechanical stability is particularly important for tissue
Scanning electron microscopy (SEM) analysis of the engineering applications, as stable scaffolds can better
surface morphology of ODMA/PEGDMA scaffolds at withstand the stresses and strains encountered in vivo and
various magnifications revealed different textures among maintain their shape and function over extended periods.
the printed samples at 70× magnification. Scaffolds 3.4. Characterization and cytotoxicity of collagen
composed of the PEGDMA resin with 0.625% ODMA hydrolysate after sterilization by various methods
exhibited square pores and a rough surface, which Investigations into the effects of various sterilization
may affect cell adhesion and cause damage due to high methods on CH revealed distinct changes. Sterilization
surface roughness. In contrast, samples with higher with EtO transformed the hydrolysate from a light brown
ODMA concentrations displayed a smoother surface powder to a burnt brown and sticky lump, which affected
finish, consistent with the printability results from its solubility in distilled water. In contrast, beta and gamma
DLP 3D printer testing. Further examination at 400× radiation did not alter its physical characteristics.
magnification displayed a consistent pattern across all
concentrations, similar to previous research using SEM The FTIR spectroscopic analysis of CH post-
techniques to examine the morphology of PEGDMA as sterilization revealed key chemical structure insights. The
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a scaffold material. However, the compactness of the amide A band appeared at 3281 cm , indicating N-H
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pattern was influenced by the ODMA concentration, with stretch vibrations, which suggests hydrogen bonding
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higher concentrations resulting in denser patterns. These within the peptide. The amide B band was identified at
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findings are detailed in Figure 8 and demonstrate the 2961 cm , corresponding to the asymmetric stretching
impact of ODMA concentration on the surface texture and vibrations of the CH groups and the presence of the alkyl
2
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microstructure of ODMA/PEGDMA scaffolds. chain. The characteristic frequency of the amide I band at
1635 cm was primarily related to the stretching vibrations
−1
3.3. Compression testing of the of the carbonyl group along the polypeptide backbone. 27,28
ODMA/PEGDMA scaffold Moreover, amide bands II and III, at 1536 and 1242 cm ,
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Figure 9 presents the stress–strain analysis comparing respectively, correspond to the flexural vibrations of N–H
pure PEGDMA with a composite material containing bonds coupled with the C–N stretching vibrations. 27,28
Volume 10 Issue 6 (2024) 347 doi: 10.36922/ijb.4385