(1203-D) A Study on Nanofiber and Microfiber Composite Structures in Tissue Engineering

Abstract: In vitro, cell cultures in Petri dishes, cultured on flat glass or plastic substrates, establish an environment significantly divergent from the physiological, physical, and diverse conditions inherent in the human body. Cells residing within the human body are enveloped by the three-dimensional space of the extracellular matrix (ECM) and tissue fluid, engaging in interactions with diverse environments, exhibiting mobility, and executing their natural activities. Consequently, maintaining, activating, differentiating, and manifesting tissue-specific functions in 2D environments, such as a Petri dish, proves challenging. Nanofibers, ranging from tens to hundreds of nanometers, find applications in various fields such as machinery, electronics, and biotechnology due to their highly porous structure and substantial volume-to-surface area ratio. Electrospinning, one of several methods for fabricating nanofibers, enables the production of continuous fibers with diameters in the micrometer to nanometer range. Additionally, 3D printing can fabricate structures with micrometer-sized diameters. The fiber diameter significantly influences fiber structure properties, including pore size and porosity, and proves to be a critical factor in cell adhesion, proliferation, and movement within tissue engineering structures. Depending on the fiber's material, length, pore size, and orientation, cells can attach by penetrating or moving between the fibers.
In this research, nanofibers were employed to replicate the environment within the human body, and structures were fabricated using microfibers for cell cultivation on the nanofibers. Consequently, we successfully demonstrated the potential to enhance the range of cell movement within the structure and improve cell proliferation capabilities. A polycaprolactone-chloroform solution was electrospun to produce both nanofibers. Polycaprolactone (PCL) with a number-average molecular weight (Mn) of approximately 80,000 was dissolved in chloroform at a concentration of 8 wt% for the electrospinning of nanofibers. The polymer used for melt-based 3D printing was PCL with an average molecular weight ranging from 43,000 to 50,000. The morphology of the electrospun nanofibers and 3D printed microfiber frames was observed using a field emission scanning electron microscope. The diameter of each fiber and frame was measured from SEM images using Image J software. Additionally, the thickness of the electrospun nanofibers and 3D printed microfiber frames was measured using a precision micrometer. The cell viability, attachment, and growth rate of the fabricated structure were assessed through an in vitro cell culture test utilizing mouse fibroblasts and HUVEC cell lines. Hence, the structure developed in this study is anticipated to prove beneficial for research involving 3D cell culture, the fabrication of structures in tissue engineering, and cell culture characterized by high cell mobility.
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. RS-2023-00241495, 2021R1A2C2014364).