Biomimetic heterogenous elastic tissue development.

"Competing interests The authors declare that they have no competing financial interests."

"Authors would like to thank Dr Mouhalan Kanapathy for expert assistance with suturing tracheal constructs to porcine respiratory system to test mechanical and structural patency. We would like to thank Dr Githa Madani for providing with the DICOM files for modelling, as well as Dr Ryo Torri at UCL, and Dr Celia Butler at Simpleware and for their extensive, generous support throughout the study with aspects of 3D modelling, Dr Matt Barlett for assistance with ultrasound measurements and Ms Helen McKenna at the Royal Free Hospital for tremendous support with the ventilator set-up. Components of this work was carried out by Halimat Afolabi (MBBS student) as part of a summer research programme and N Brown, N Wadlie (year 3 Medical students at UCL) as part of their intercalated BSc project under the supervision of Achala de Mel (course director of iBSc Surgical Sciences). AdM is an Investigator of direct 3D printing project, which was partly funded by EPSRC Additive Manufacturing in Healthcare grant project EP/L020904/1 and KJT is partically funded by BioHORIEN Biochemical Technology Co-Ltd. Authors would like to gratefully acknolwdge Biomer Technology Ltd for their in-kind support of material and material development expertise for this project."