Injectable nanofibrous microscaffolds for cell and drug delivery

Jun 29, 2022, 2:30 PM
10m
Room: S3 B

Room: S3 B

Speaker

Nakielski, Paweł (Institute of Fundamental Technological Research PAS)

Description

"Injectable biomaterials for cell and drug delivery is a rapidly expanding field that may revolutionize medical therapies. Here we report on the fabrication of injectable electrospun microscaffolds used to deliver desired cargo through the needle. We observed an efficient attachment of cells to the scaffold's surface, creating cell-populated microscaffolds (MS) that could be injected or 3D printed through 23-26G needles.

Polymer nano- and microfibers were electrospun and then structured with a picosecond laser. To increase the hydrophilicity of the MS, nanofibers were first hydrolyzed with sodium hydroxide and then functionalized with natural polymers like chitosan or chondroitin sulfate. For morphological characterization of MS with and without cells, we used Scanning Electron Microscopy (SEM). Physico-chemical characterization was done to analyze the impact of laser processing on polymer nanofibers. We used the L929 cell line to assess the biocompatibility of produced MS and the possibility of injecting the construct into the desired tissue. Nucleus pulposus cells were used as the target cells to evaluate their survival after injection through different needle sizes.

The direct injection of cells into tissues faces several challenges, such as low survival and their retention at the injection site. With cell-protective MS, the survival rate can be significantly increased. When using laser processing, any shape of microscaffolds can be created, among others, MS with quadrilateral, triangular or circular base. Moreover, low melting of the fibres at the cut surfaces can be observed. The cytocompatibility assays show an increase in cell number with culture time. L929 cells populated MS at each side, resulting in the formation of agglomerates. The injectability studies through 24G and 23G needles showed that the ejection rate was 97% and 98%, respectively.

We developed a novel and straightforward method to fabricate microscaffolds from almost any type of electrospun material. MSs are compatible with living tissues and readily populated with cells. By designing the surface chemistry of nanofibers, the physical and chemical structure of MSs can be customized to improve cell-MS interaction. The injectability studies show that PLLA-based MSs are injectable through the tested range of needle sizes and could be well‐suited for minimally invasive cell delivery applications. One of the examined applications is intervertebral disc degeneration, where designed MS delivers active molecules that enhance the synthesis of glycosaminoglycans. A single administration of the drug in the MS to the tissue will result in several weeks of the release of the active substance, which may have a beneficial effect on the regenerative processes of the intervertebral disc.

Acknowledgements: This work was supported by the National Centre for Research and Development grant no. LIDER/14/0053/L-9/17/NCBR/2018 and National Science Centre no. 2015/19/D/ST8/03192.
References: Nakielski P. et al., Small, 18, 2104971 (2022)"
20941818568

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