Application of magnetic anchors to align collagen fibres for axonal guidance / Devindraan Sirkkunan

Devindraan , Sirkkunan (2024) Application of magnetic anchors to align collagen fibres for axonal guidance / Devindraan Sirkkunan. PhD thesis, Universiti Malaya.

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Abstract

The use of ex-vivo treated hydrogels such as electro- and microfluidic-spun scaffolds that necessitate surgery for application has led to the rise in the research of injectable hydrogel in recent years. Its use could circumvent the need for surgery. However, methods to control these hydrogels’ internal structure must be developed, as it is highly defined in their ex-vivo counterparts. Here, we have developed a “magnetic anchor” method to improve the orientation of collagen fibers within 3D scaffolds. This procedure sees the use of (Gold Magnetic Nanoparticles) GMNP “anchors” capped with (Collagen Mimetic Peptide) CMPs that attaches them to the collagen fibers and aligns these strands through the application of a magnetic field during the solidification process. This study also compares the “magnetic anchor” method and the “magnetic particle string” method that has been proven to improve the orientation of collagen fibers. It was shown in this study that the application of CMP/GMNP in a magnetic field greatly improves alignment of the collagen fibers, which in turn, improves the orientation of (Pheochromocytoma Cells) PC12 neurites. This collagen alignment was even greater in magnitude compared to the “magnetic particle string” method, which requires the utilization of a higher concentration of magnetic nanoparticles. The growth of these collagen fibers was also improved as they were significantly longer using the “magnetic anchor” method. Furthermore, the PC12 cells grown in collagen gels treated using the “magnetic anchor” method showed comparable cellular viability to the untreated collagen gels. This proves the “magnetic anchor” method does not have any adverse effects on cellular growth. The neurites projecting from the differentiated PC12 cells were also much more aligned using the “magnetic anchor” method. The directionality of 86% of the neurite cells on scaffolds fabricated with the “magnetic anchor” method were shown to align within ±30° of the mean threshold. The is a vast step up in the technology used to align collagen fibers as the “magnetic particle string” method was only capable of aligning 38% of the neurite extension within this mean threshold. In summary, this method is an improvement over current nanoparticle technologies used to align collagen fibers, as it uses less nanoparticles to produce collagen fibers that are much more aligned and in turn guides the neurites to greater alignment. This capability to remote control the alignment of injectable collagen scaffolds opens new strategic avenues in the research for treating debilitating neural tissue pathologies.

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