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Description
Introduction
In Europe, around 60 million people have diabetes, and approximately 15% will develop diabetic foot ulcers (DFUs), with annual treatment costs of €4–6 billion [1]. Neuropathy hinders early wound detection, complicating DFU management [2]. Electrospun structures mimic the skin’s extracellular matrix but their 2D nature limits full regeneration [3]. This study proposes to create a 3D electrospun-based scaffold with nanodetails to fill the entire wound and enhance healing. Polycaprolactone (PCL) short nanofibres (SNFs) will be incorporated into a gelatin bioink combining mechanical strength with biocompatibility. Gelatin also promotes cell adhesion and proliferation through its characteristic RGD peptide sequence [4].
Methods
Electrospun meshes were produced from a 16 wt% PCL solution using a home-made electrospinning apparatus. The fibers were cut with NaOH and dispersed in a 5 wt% gelatin solution to prepare inks with varying SNF contents (100:6.4, 100:10, 100:20). BDDGE crosslinker was added, and the inks were 3D-printed using a home-made BIOMATE system to form scaffolds. Double crosslinking process was carried out in a BDDGE/methanol bath. FTIR-ATR was used to confirm the incorporation of BDDGE and the presence of PCL. Mechanical properties were evaluated via compression tests at 5 mm/s with a 300 N load cell, and 80% of strain on wet samples. Morphological analysis was performed by SEM and µCT.
Results
Different concentrations of SNFs dispersed in the ink were tested to prepare 3D electrospun-based hydrogels by bioprinting, and the processing parameters were optimized. According to the FTIR analysis, a PCL band at 1726 cm-1 and BDDGE at 2943 cm-1 and 1856 cm-1 could be seen in all conditions. SEM images showed the homogeneous dispersion of SNF's, incorporation into the 3D hydrogel filaments and the porous presence in the surface, which was also demonstrated in µCT images. Moreover, with increasing amount of SNFs, the compressive modulus also increased, indicating a higher stiffness, which is relevant to mimic the skin mechanical properties.
Discussion
FTIR-ATR and SEM analysis confirmed the presence of SNF in the hydrogel filaments. Nevertheless, the FTIR-ATR bonds of the primary gelatin amides, associated with the incorporation of the crosslinker BDDGE, are visible. Mechanical analysis indicates the occurrence of viscoelastic behavior with memory, in the present study was demonstrated a direct influence of SNFs in the compressive tests.
References
[1] Moura L.et al., 2013, 10.1016/J.ACTBIO.2013.03.033.
[2] Volmer-Thole M.et al., 2016, 10.3390/ijms17060917.
[3] Dias J.et al., 2016, 10.1016/j.pmatsci.2016.09.006
[4] Ferreira C.et al., 2021, 10.3390/pharmaceutics13122152
Acknowledgment:
This study was supported by the Fundação para a Ciência e a Tecnologia (FCT) through the Strategic Projects granted to CDRSP: UIDB/04044/2020; (doi.org/10.54499/UIDB/04044/2020), UIDP/04044/2020 (doi.org/10.54499/UIDP/04044/2020), to the Associate Laboratory ARISE (LA/P/0112/2020) and PTCentroDiH project (03/C16-i03/2022–768); the grant awarded to Carolina Ferreira (2021.04541.BD) [JD1] and the funding to Juliana Dias (10.54499/CEECINST/00060/2021/CP2902/CT0005). This study was also supported by INOV.AM – Inovação em Fabricação Aditiva, 02-C05-i01.01-2022, Nanofilm (CENTRO2030-FEDER-01469100).
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