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Liu F, et al.

A colonization and proliferation. Furthermore, with the full-
layer plasma modification capability, the plasma active
species can reach the walls of the pores on each layer
of the scaffold, leading to the uniform cell distribution
along the scaffold. This will enable a higher rate of tissue
formation in the clinical research.

5. Conclusion
This paper presents a novel AM system comprising a
multi-material printing unit and a plasma jet unit. To
assess the system, hybrid PCL/hydrogel scaffolds and
full-layer plasma treated PCL scaffolds were produced.
The effect of plasma treatment on PCL samples was
examined. WCA results confirmed that the hydrophilic
character of the PCL samples increased due to the
B nitrogen groups introduced by the plasma jetting on the
scaffold filaments. It was also possible to observe that the
plasma treatment positively influences cell attachment
and proliferation. Applications that may benefit from this
technology include hybrid tissue, which has compositional
variations depending on the region or organ-like structure
that require the continuous vascular network to facilitate
nutrient diffusion.

Acknowledgments

The authors wish to acknowledge the support from the
School of Mechanical, Aerospace and Civil Engineering
at the University of Manchester.
Figure 5. (A) Temporal variation of fluorescence intensity of cell-seeded
PCL scaffolds with and without N plasma treatment; (B) confocal Conflicts of Interest
2
microscope images of untreated and full-layer treated of cell-seeded
scaffolds, 1 day and 14 days after cell culture. Scale bar 250 µm. The authors declare that they have no conflicts of interest.
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