Page 401 - IJB-10-6

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

While all these studies proved the effectiveness of PCL The sample was scanned at 10°–80° with a 0.05° step size.
and MNP scaffolds in bone tissue regrowth (i.e., due to their MgFe O nanoparticles were found to be less susceptible
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biocompatibility and the regulatory approval of MNPs from to oxidation compared to Fe O ; therefore, they are more
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the FDA for clinical use), they still were limited in other effective as hyperthermia agents due to their large heating
ways. Apart from adequate cell viability and proliferation, capacity. The average particle size is 20 nm, as verified
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the scaffolds failed to have sufficient mechanical strength by transmission electron microscopy (TEM; Talos F200X;
that matches that of the native bone. This study addressed Thermo Fisher Scientific, USA). The stability of the
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this challenge by fabricating scaffolds with concentrations MNP solution was determined using a Malvern zetasizer
as high as 50% to explore the possibility of these additional (Malvern Panalytical Pvt. Ltd., UK).
MNPs seeping into the polymer matrix and increasing the
mechanical strength closer to that of the trabecular bone. 2.2. 3D printing
Briefly, 2 g of PCL pellets (molecular weight [Mw]: 80,000
In addition to boosting the mechanical strength to kDa; Sigma-Aldrich, United States of America [USA])
match the native bone, the incorporation of a higher amount were dissolved in 5 mL acetic acid solution to obtain a
of MNPs still maintains the cell viability of the scaffolds, 40% (w/v) PCL solution, which was then ultrasonicated
thereby preserving their biocompatibility. Moreover, a for 3 h to fully dissolve the pellets. Thereafter, MNPs were
greater amount of MNPs is directly correlated to increased weighed using a balance and added to the solution at 2.5%,
heating capacity upon the application of a magnetic field; 5%, 7.5%, 10%, 30%, and 50% (w/v). The resulting solution
the scaffold would reach hyperthermic temperatures much was then ultrasonicated for 5 h until a uniform mixture of
earlier. Furthermore, the use of a PCL-MNP solution in an MNPs was obtained; if ultrasonication was not performed
extrusion printhead allowed for the printing of relatively properly, the MNPs would coagulate. Once uniformly
complex structures with high resolution compared to using dissolved, the mixture was filled in a syringe and extruded
a die-cast. While several different additive manufacturing using the extrusion printhead of the bioprinter (RegenHU
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processes exist for fabricating these scaffolds, each with 3D Discovery, Switzerland) with a nozzle of diameter 0.41
its own set of advantages and limitations, extrusion 3D mm at a pressure of 0.06 MPa. The printed scaffolds had a
printing allows us to achieve the desired shape with relative grid-like structure with dimensions 2 × 2 cm.
simplicity. 24,34
2.3. Scaffold characterization
Cancer management after tumor resection is The 3D-printed scaffolds were imaged using scanning
characterized by two critical needs: (i) rehabilitation of the electron microscopy (SEM; Quanta 450 FEG, FEI
TM
resected tissue and its reconstruction, and (ii) preventing company, USA) after sectioning the scaffolds and
the recurrence of tumors post-surgery by destroying any coating the cross-section with gold. The scaffolds
residual tumors. The state-of-the-art in literature is limited were characterized using Fourier-transform infrared
because it tackles these two major priorities individually: spectroscopy (FTIR; Invenio S; Bruker, USA) in a frequency
achieving tissue resection via autologous grafting and range of 400–4500 cm to determine the constituent
−1
preventing tumor recurrence through chemotherapy. In chemical groups. Uniaxial tensile tests were carried out
this study, we 3D printed a custom PCL-MNP scaffold with using an Instron machine (Universal Testing System-5960
MNP concentrations ranging from 0% to 50%, achieving series; Instron, USA), with a cross-head speed of 1 mm/
our four primary objectives: (i) demonstrating the ease min and a 5 kN load cell. The load versus displacement
of 3D printing for patient-specific customization of the data obtained from the tensile test allowed us to determine
scaffold according to the critical size defect; (ii) providing the stress versus strain curve along with the modulus of the
adequate mechanical strength under physiological loads; individual samples.
(iii) aiding in bone tissue regeneration by enhancing
hMSC functionality; and (iv) inducing cancer cell death Thermal degradation properties were assessed using
due to the hyperthermia effect caused by the application of a thermal gravimetric analyzer (TGA; TG209 F1 Libra;
an external AMF. Netzsch, Germany). The samples were heated from 25 to
500°C, with a 10°C/min step size. A differential scanning
2. Methods calorimeter (DSC; Q2000 V24; TA Instruments, USA) was
used to evaluate samples in the range of −90 to 120°C, with
2.1. Magnetic nanoparticle characterization a 10°C/min step size. After reaching 120°C, the samples are
The chemical composition of the nanoparticles (Luoyang cooled at 10°C/min and heated again at the same rate.
Tongrun Info Technology Co. Ltd., China) is MgFe O as
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determined by X-ray diffraction (XRD) analysis (Empyrean Magnetic hysteresis loops were measured using a
3; Malvern Panalytical Pvt. Ltd., United Kingdom [UK]). physical property measurement system (PPMS; DynaCool

Volume 10 Issue 6 (2024) 393 doi: 10.36922/ijb.4538