Abstract
Skeletal muscle engineering is focused on the regeneration of irreversibly damaged skeletal muscle in conditions such as volumetric muscle loss. Skeletal muscle can be regenerated in vivo and in vitro by combining a biocompatible scaffold, skeletal muscle-derived stem or precursor cells, and any necessary bioactive molecules. Scaffolds used for this purpose must be biocompatible, while providing physical and biological cues needed to guide muscle development. Various biomaterials and biofabrication techniques have been used to generate scaffolds, however, most that meet these engineering requirements present ethical and/or sustainability concerns.
This research focused on the assessment of cellulose-based scaffolds isolated from a New Zealand seaweed for use in skeletal muscle engineering. The aim was to generate a cellulose-based scaffold from the brown kelp Ecklonia radiata, and compare the biocompatibility of scaffolds isolated using chemical or pulsed electric field (PEF) decellularisation. Pulsed electric field processing is non-thermal processing technique where an electric field is applied to intact laminae of E. radiata. The PEF decellularisation technique was implemented to reduce the need for long-term chemical exposure and accelerate the decellularisation process. It was hypothesised that PEF-generated scaffolds would show greater biocompatibility with skeletal muscle cells than chemically-generated equivalents.
First, the structure, composition, and extent of decellularisation of E. radiata scaffolds isolated by PEF and chemical processing were analysed. The DNA and pigment content of the seaweed scaffolds were reduced to an equivalent extent, irrespective of their method of decellularisation. The integrity of the cellulose matrix showed greater swelling and loss of internal fibres with chemical and PEF processing relative to the unprocessed seaweed. However, there was significant structural variability between samples.
Next, the biocompatibility and utility of the seaweed scaffolds for skeletal muscle engineering were evaluated using murine C2C12 myoblast cells. Cell viability and myofibre formation on PEF scaffolds was equivalent to chemical scaffolds. Results suggest myoblast attachment after 24 hours of culture was greater for the PEF scaffolds. Histology and microscopy at 1, 5 and 7 days of differentiation, indicated that the myofibre formation may be accelerated and maintained on the PEF scaffolds to a greater extent than on the chemical scaffolds.
Overall, the results indicate that chemical and PEF treatment of E. radiata can produce cellulose scaffolds that support myofibre formation to an equivalent extent. Further research is needed to fully define the scaffold composition and assess compatibility with human cells, functionality of the generated skeletal muscle, and translatability in vivo.