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

Figure 3. Illustration of the printing of ODMA/PEGDMA using a DLP 3D printer. (a) During printing, inside the blue circle is the ODMA/PEGDMA
resin. (b) The scaffold model before printing in the CHITUBOX program. (c) The scaffold after it has been printed. Abbreviations: DLP, digital light
processing; ODMA, oligomer of dopamine methacrylate; PEGDMA, polyethylene glycol dimethacrylate.

ODMA (10% ODMA/PEGDMA). The compression tests subjected to a stream of warm air at approximately 46°C
were performed using a dynamic mechanical analyzer under atmospheric pressure for 48 h. This crucial step
(TAXT plus Stable Micro Systems, United Kingdom [UK]). ensures the complete removal of any residual EtO, thereby
A preload force of 0.001 N was applied to standardize the eliminating potential toxicity and ensuring the safety and
interface between the top plate and the sample surface sterility of CH for medical and nutritional applications.
to ensure contact uniformity. These tests proceeded at a
consistent compression rate of 1 mm/min at ambient room 2.8.2. Beta radiation sterilization
temperature. The compressive modulus was calculated Collagen hydrolysate (CH) was first securely enclosed in a
from the initial linear zone of the stress–strain curve, which sealed medicinal pouch and placed inside an opaque sealed
represents the material’s response from 0% to 50% strain. box for protection against light and external contamination.
The samples underwent beta radiation treatment, ensuring
2.8. Sterilization of collagen hydrolysate thorough sterilization with a minimum radiation dose of
17.5 kGy.
2.8.1. Ethylene oxide sterilization
This sterilization process was conducted in accordance 2.8.3. Gamma radiation sterilization
with EN ISO 11135 standards, utilizing EtO for its Collagen hydrolysate (CH) was meticulously packaged
effective antimicrobial performance. CH was first within a hermetically sealed medicinal pouch for its
securely packaged in sterile bags to maintain purity. The purity and integrity. This pouch was placed inside an
samples were then exposed to an EtO gas atmosphere at opaque, sealed box to protect against light and external
a concentration of 700 mg/L with 70% relative humidity contamination. The packaged CH underwent sterilization
for 8 h at a controlled temperature of 55°C. Following this, through exposure to gamma radiation at a minimum
a detoxification process was employed, wherein CH was radiation dose of 17.5 kGy.

Volume 10 Issue 6 (2024) 342 doi: 10.36922/ijb.4385