Nanocellulose materials have novel and improved properties compared to traditional cellulose materials. This, combined with the demand for high value-added products and applications made from renewable and sustainable resources, makes nanocellulose an appealing material candidate in many fields.
“Many applications would benefit from materials that have aligned structures. This is why the alignment of cellulose nanofibers has also been investigated for various purposes, including for advanced biomedical materials and applications”, Anne Skogberg says.
The alignment of cellulose nanofibers is challenging as such, and even more challenging in the presence of other materials.
“Even though the nanocellulose fibrils are hierarchically aligned in their native state in plants, after disintegration, their realignment is challenging for bulk applications,” Skogberg notes.
In her interdisciplinary study, Skogberg investigated the alignment of nanocellulose fibres and their influence on cells, particularly on cell alignment. Nanocellulose fibres were successfully oriented intentionally, both on their own and when mixed with carbon nanotubes, using an evaporation-based self-assembly. As the nanocellulose fibres dried, they were observed to align themselves parallel to the drying path of the liquid droplet along the interface between the liquid droplet, air, and the substrate surface. This behaviour had not been observed with fibrous nanocellulose before.
When cell growth was examined on these oriented nanocellulose substrates, cells were found to elongate with the direction of the aligned nanocellulose fibres. This is referred to as cell orientation. The finding offers potential applications for future cell-based technologies.
One part of the research was conducted in collaboration with researchers at the Czech Academy of Sciences. Nanocellulose coatings were used to improve cell growth on low-cost cellulose meshes that could be utilised as a cell carrier in skin tissue engineering.
The incorporation of nanocellulose and carbon nanotubes, as well as the resulting hybrid films with directional conductivity, were designed and manufactured as part of an internal collaboration of research groups at Tampere University. Oriented nanocellulose fibres in the composite film created insulating layers between the conducting carbon nanotubes.
“The finding opens opportunities for novel applications that require directional conductivity, such as in advancing technologies for flexible electronics,” Skogberg explains.
The orientation of nanocellulose fibres, both on their own and in composite films, constitutes fundamental research and can be utilised in various fields for further studies.
“I am eagerly awaiting how other researchers worldwide will leverage these findings,” says Skogberg.
Public defence on Friday 17 November
The doctoral dissertation of M.Sc. Anne Skogberg in the field of Biomedical engineering titled Cellulose Nanofibers and their Assembly for Biomedical and Material Sciences, Focus on Charged Cellulose Nanofibers will be publicly examined at the Faculty of Medicine and Health Technology of Tampere University at 12.00 on Friday 17 November 2023. The venue is the Festia auditorium FA032 on the Hervanta campus (address: Korkeakoulunkatu 8, Tampere). The opponent will be Professor Kristin Syverud from the Norwegian University of Science and Technology. Professor Pasi Kallio from Tampere University acts as the Custos.