Polycaprolactone (PCL) has emerged as a promising material in tissue engineering due to its biocompatibility, biodegradability, and favorable mechanical properties. In this study, we present a comprehensive characterization of melt-electrowritten (MEW) PCL fibers fabricated using a custom-built MEW system with a focus on their structural and mechanical behavior relevant to biological applications. The fibers were produced at 110 °C using a conical metallic nozzle with a 200 µm hole diameter, under applied voltages ranging from 3 to 4 kV and pneumatic pressures between 0.3 and 1 bar. The resulting fiber diameters varied from 13 ± 3 µm to 34 ± 2 µm, depending on the process parameters, with higher pressure leading to increased mass flow and larger diameters.
Scanning electron microscopy (SEM) revealed that the fibers exhibit a smooth, continuous morphology without bead formation when processed under optimal conditions. However, at low voltages (<3 kV), instabilities in the molten jet led to irregular beading and discontinuous deposition. X-ray scattering analysis confirmed the presence of semicrystalline structures within the fibers, with characteristic reflections corresponding to PCL (110) and (200) crystal planes. Small-angle X-ray scattering (SAXS) data indicated a moderate degree of uniaxial orientation of lamellar domains, particularly at mid-q values (0.3–0.6 nm⁻¹), suggesting alignment along the fiber axis despite the absence of strong chain stretching. This is attributed to the rapid solidification of the polymer upon contact with the substrate, which limits chain relaxation and prevents full crystallization into highly oriented structures. Dynamic mechanical analysis (DMA) performed from 20 to 37 °C at a heating rate of 2 °C/min showed that the storage modulus of the MEW-PCL fibers was 9.3 ± 0.5 MPa at 20 °C, decreasing slightly to 8.4 MPa at 37 °C. The loss modulus also decreased from 1.09 ± 0.05 MPa to 0.99 MPa, indicating a reduction in viscoelastic damping with temperature. These values are comparable to those of native collagen fibrils (~1.1 MPa), making MEW-PCL an excellent candidate for mimicking the mechanical environment of soft tissues. Differential scanning calorimetry (DSC) measurements revealed a melting peak at approximately 59 °C and a crystallinity degree of about 68%, consistent with SAXS results. The influence of processing parameters on fiber morphology was systematically evaluated. Increasing the applied voltage from 3 to 4 kV resulted in a significant increase in fiber diameter—up to 30 µm at 1 bar pressure—suggesting enhanced electrostatic drawing forces. However, this effect was less pronounced at lower pressures (0.3 bar), where the increase was only up to ~17 µm. Conversely, reducing pressure from 1 to 0.LMNB2 Antibody Purity & Documentation 3 bar reduced the fiber diameter by more than half, highlighting the dominant role of pneumatic force in controlling mass transfer through the nozzle. The zeta potential measurements demonstrated that the surface charge of PCL fibers shifts positively after coating with fibronectin-collagen-albumin (FNC) mixture, indicating improved hydrophilicity and protein adsorption capacity, which is critical for cell adhesion.SULT1A1 Antibody site
The mechanical robustness of the fibers was further assessed via tensile testing and nanoindentation, confirming their ability to withstand physiological stresses.PMID:34949672 Importantly, no significant shrinkage was observed upon heating near the melting point, unlike electrospun fibers, which typically undergo substantial contraction due to high chain orientation. This behavior confirms the lack of residual stress and high molecular relaxation in MEW-fabricated fibers, enhancing their long-term stability in biological environments.
These findings underscore the advantages of MEW over conventional electrospinning for fabricating biomimetic scaffolds: superior control over fiber geometry, tunable mechanical properties, and compatibility with complex multi-material architectures. The combination of precise spatial patterning and intrinsic structural features makes MEW-PCL ideal for engineering aligned tissues such as muscle, nerve, and tendon. Future work will explore the integration of these fibers into hybrid hydrogel systems for dynamic, responsive scaffolds capable of guiding cell behavior through both topographical and mechanical cues.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com