Electrospinner: Surface modified nanofibers: vapor deposition of biomolecules to enhance cell adhesion and alignment!

Background

Poly(l-lactone-co-ε-caprolactone) (PLCL) is a multifunctional copolymer with excellent biocompatibility and biodegradability. It is widely used in the biomedical field due to its elasticity and easy processing. However, the hydrophobic nature of PLCL limits its application in neural cell culture.

Recently, the team of Professor Hyejeong Seong/Jin Yoo of the Korea Institute of Science and Technology published a research result entitled "Facile surface functionalization of electrospun elastic nanofibers via initiated chemical vapor deposition for enhanced neural cell adhesion and alignment" in Advanced Fiber Materials. The research systematically described the use of chemical vapor deposition (iCVD) technology to coat PLCL nanofibers with a copolymer containing poly(pentafluorophenyl methacrylate) (PFMA) and divinylbenzene (DVB), p(PFMA-co-DVB), so that biomolecules can be fixed on the surface of PLCL nanofibers. By adjusting the monomer flow rate, the composition of the polymer can be precisely adjusted. The resulting copolymer showed excellent efficiency in fixing immunoglobulin G (IgG). In vitro studies on different types of neural cells showed that the coated fibers significantly enhanced cell adhesion while maintaining their inherent biocompatibility; the elastic properties of the PLCL nanofibers were verified by quantitative analysis of scanning electron microscopy and immunofluorescence images, indicating the potential of iCVD-modified PLCL nanofibers in neural tissue engineering and various biomedical applications.

The main point of this paper

Figure 1 shows the steps of coating uniform polymer Nanofiber Membrane on PLCL nanofibers during the iCVD process, and the subsequent biomolecule fixation process. Among them: Figure 1 (a) shows that the monomer and initiator are introduced into the iCVD reaction chamber by gentle heating, the heating filament activates the initiator into free radicals, the monomer is polymerized on the PLCL Electrospun Nanofbers, and the biomolecule is fixed on the PLCL Electrospun Nanofbers using pPFMA active ester; Figure 1 (b) shows the surface morphology and root mean square roughness (RMS) of different polymers (including bare silicon wafers, pP4D1, pP8D1 and pPFMA) measured by atomic force microscopy (AFM); Figure 1 (c-d) shows the unique chemical bond characteristics of PFMA and DVB shown in the FTIR spectrum, and the XPS spectrum further confirms the presence of functional groups such as C-F, C-O, and C=O in the iCVD polymer Nanofiber Membrane.

From the XPS analysis results of Figure 2(a), it can be seen that IgG was successfully immobilized on the pPFMA surface; through the fluorescence intensity quantification of Figure 2(b), it was found that the fluorescence intensity on the surface of the pP4D1 copolymer was the highest, indicating that its biomolecule immobilization efficiency was the best; AFM and QCM-D techniques were used to demonstrate the immobilization efficiency and surface characteristics of IgG on different polymer Nanofiber Membranes, and the results are shown in Figure 2(c-d), confirming that the surface of the pP4D1 copolymer is conducive to the immobilization of biomolecules.

Figure 3 shows the physical properties of PLCL Electrospun Nanofibers and their polymer coatings. Through the SEM analysis of Figure 3(a), it was found that the average diameter of the fiber increased slightly after coating with pP4D1, while the diameter of the aligned PLCL/pP4D1 nanofibers after applying 90% strain decreased, indicating that neither the coating nor the strain treatment destroyed the structure of the Electrospun Nanofibers; in addition, it was shown that the non-aligned PLCL and PLCL/pP4D1 Electrospun Nanofibers were randomly oriented, while the aligned nanofibers showed specific directionality. From the mechanical properties analysis results in Figure 3(b), it can be seen that the iCVD-coated PLCL Electrospun Nanofbers maintain similar mechanical strength and flexibility as the original PLCL nanofibers, indicating that the effect on the mechanical properties is not significant. The above analysis results show that the iCVD technology can effectively promote surface functionalization while maintaining the physical structure and mechanical properties of PLCL Electrospun Nanofbers.

Through in vitro experiments, SH-SY5Y neuroblastoma cells and PC12 adrenal pheochromocytoma cells were subjected to biological reactions on differently treated PLCL Electrospun Nanofbers. The results are shown in Figure 4. It can be seen that compared with bare nanofibers with only physical adsorption of laminin, Electrospun Nanofbers coated with pP4D1 by iCVD and chemically fixed with laminin significantly enhanced cell adhesion and diffusion. Cells showed a larger diffusion area and extension along the fiber direction on these functionalized surfaces; and the directional elongation of cells was further promoted by controlling the arrangement of Electrospun Nanofbers, indicating the potential application of iCVD functionalized PLCL nanofibers in the field of neural tissue engineering, and surface functionalization can effectively promote cell interaction.

In summary, this work provides a new method to improve the properties of the Electrospun Nanofbers surface, making it more suitable for the culture of neural cells and tissue engineering applications. Creating a special coating that promotes cell adhesion and alignment on the surface of Electrospun Nanofbers by iCVD technology is of great significance for the development of new biomedical materials.

Electrospinning Nanofibers Article Source:

https://link.springer.com/article/10.1007/s42765-024-00438-0