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International Journal of Bioprinting 3D-printed PCL-MNP multifunctional scaffolds

(Figure 1E). The XRD analysis allowed us to determine Once the MNPs were characterized, scaffold preparation
the concentration of different elements in the sample. was carried out. A 40% (w/v) solution of PCL was used
Figure 1D displays peaks at 2Ѳ = 31, 36, 43, 54, 57, and as the base material. To this solution, 0–2.5 g MNPs were
63. XRD analysis was conducted through the Execute added to obtain 0–50% (w/v) PCL-MNP solutions (0%,
Search and Match tool, and a match with magnesioferrite 2.5%, 5%, 10%, 20%, 30%, and 50%). The printing process
was observed. The FTIR spectra in Figure 1E revealed the is represented in Figure 2A. It can be observed from the
chemical bonds in the MNPs. A sharp peak was observed printed scaffold that the extrusion 3D printing process was
successful in fabricating a scaffold of desired dimensions
−1
around 540 cm , indicative of the Fe-O bond in the (2 × 2 cm), comprising a uniform mixture of PCL and
materials, thus pointing towards iron oxide nanoparticles. MNPs, with high resolution and relative ease. From
Figure 1F displays the zeta potential of MNPs in the Figure 2B, we observe that pure PCL is unaffected when an
suspension. The zeta potential determines the suspension external magnet is applied, while the scaffold with MNPs
stability. Nanoparticles with a zeta potential in the range of is attracted to it, validating the magnetic characteristic of
−30 to +30 mV display great potential for agglomeration; the MNP scaffold.
therefore, they are characterized as having low stability. Three representative PCL-MNP scaffolds and their
Particle stability is directly proportional to their charge. scanning electron microscopy (SEM) images are displayed
At a zeta potential higher than +30 mV or lower than in Figure 2C–E. The SEM images were obtained at
−30 mV, good stability is achieved, signified by a lack resolutions of 100 and 500 µm after cutting the scaffolds
of agglomerates. The MNP suspension that was tested and coating the cross-section with gold. While the pure
exhibited an average zeta potential of −15.9 mV. PCL scaffold cross-section has relatively larger pores, the
10% and 50% scaffolds displayed a more filled internal
3.2. Characterization of 3D-printed structure due to the magnesioferrite nanoparticles settling
PCL-MNP scaffolds within the polymer matrix. The scaffolds with MNPs were

Figure 2. Extrusion 3D printing of PCL and PCL-MNP scaffolds. (A) Printing process of PCL-MNP scaffolds using the RegenHU bioprinter. (B) Effect
of magnet on pure PCL and PCL-MNP scaffolds. (C–E) Scanning electron microscopy (SEM) images of three representative scaffolds: pure PCL (C), PCL
with 10% MNP (D), and PCL with 50% MNP (E). Scale bars: 0.5 cm (A); 100 µm (C–E); 500 µm (C–E, inset). Abbreviations: CAD, computer-aided design;
MNP, magnetic nanoparticle; PCL, polycaprolactone.

Volume 10 Issue 6 (2024) 396 doi: 10.36922/ijb.4538