Proceedings of the
9th International Conference of Asian Society for Precision Engineering and Nanotechnology (ASPEN2022)
15 – 18 November 2022, Singapore
doi:10.3850/978-981-18-6021-8_OR-03-0022
Biodegradable Mesh Sheets as A Treatment Device for Acute Type A Aortic Dissection Equipped with North American Porcupine-Inspired Microneedle for Removal Prevention
1Graduate School of Biology-Oriented Science and Technology, Kindai University, 930 Nishimitani, Kinokawa,Wakayama, 649-6493 Japan
2Department of Thoracic and Cardiovascular Surgery, Wakayama Medical University,811-1 Kimiidera, Wakayama,Wakayama, 641-8509 Japan
3Department of Cardiovascular Medicine Wakayama Medical University,811-1 Kimiidera, Wakayama, Wakayama, Japan
4Faculty of Biology-Oriented Science and Technology, Kindai University, 930 Nishimitani, Kinokawa, Wakayama, 649-6493 Japan
ABSTRACT
A common repair for acute type A aortic dissection is anastomosis to replace the ascending aorta and hemi arc. Prior to the replacement, to obliterate the false lumen, the Bio glue is applied inside of the false lumen to reinforce the fragile nature of the disrupted aortic tissue. However, Bio glue has cytotoxicity which can damage fragile aortic tissue and cause re-dissection in long term due to its aldehyde compounds. On the other hand, microneedles have been researched for many decades as a transdermal drug delivery system. Dissolving or coated microneedle patches provide low-cost, rapid, pain-free, and direct way to deliver drugs into the dermal layer. From entirely different prospective, we previously reported that a biodegradable micro-needled mesh sheet (MNMS) to be a promising candidate of intracorporal topical hemostasis device that replace tissue-derived biomaterial to avoid a latently risk of infection. However, the MNMS, made with poly lactic acid (PLA), was required to improve its poor adhesion to soft tissue. Here we focused on North American porcupines’ specialized barbs from a biomimetic point of view. The geometry of the barbs enables easy penetration and superior tissue adhesion. In this study, inspired by the barbs of North American porcupine, we developed a MNMS as an artificial tunica media made with biodegradable material to replace Bio glue in cardiovascular surgeries. The geometry of the supporting structure of the microneedles was designed to be compliant enough to fit soft tissue. The master mold of the MNMS was designed and modeled on a 3D CAD software (Fusion 360, Autodesk), and printed by an ultra-high resolution SLA 3D printer (SONIC MINI 8K, phrozen). A negative mold of the photocurable resin microstructure was obtained by silicone elastomer (Sylgard 184, Dow Corning) casting. A PLA mesh sheet with specialized mesh pattern was printed by using a FDM 3D printer (Pro2, RAISE). The final product, MNMS of PLA, was formed by heat imprinting of the PLA mesh sheet onto the elastomer female mold that has the microneedles and supporting structure relief pattern. Adhesive properties of MNMSs to Parafilm was examined by 90° peel test. As a result, the biomimetic geometry of the microneedle, inspired by the barbs of North American porcupine, improved the MNMS adhesion to parafilm up 70%. These findings should serve as the basis for the development of biodegradable MNMS to replace Bio glue in cardiovascular surgeries.
Keywords: Type A aortic dissection, Artificial tunica media, Biodegradable microneedle.
1Graduate School of Biology-Oriented Science and Technology, Kindai University, 930 Nishimitani, Kinokawa,Wakayama, 649-6493 Japan
2Department of Thoracic and Cardiovascular Surgery, Wakayama Medical University,811-1 Kimiidera, Wakayama,Wakayama, 641-8509 Japan
3Department of Cardiovascular Medicine Wakayama Medical University,811-1 Kimiidera, Wakayama, Wakayama, Japan
4Faculty of Biology-Oriented Science and Technology, Kindai University, 930 Nishimitani, Kinokawa, Wakayama, 649-6493 Japan
ABSTRACT
A common repair for acute type A aortic dissection is anastomosis to replace the ascending aorta and hemi arc. Prior to the replacement, to obliterate the false lumen, the Bio glue is applied inside of the false lumen to reinforce the fragile nature of the disrupted aortic tissue. However, Bio glue has cytotoxicity which can damage fragile aortic tissue and cause re-dissection in long term due to its aldehyde compounds. On the other hand, microneedles have been researched for many decades as a transdermal drug delivery system. Dissolving or coated microneedle patches provide low-cost, rapid, pain-free, and direct way to deliver drugs into the dermal layer. From entirely different prospective, we previously reported that a biodegradable micro-needled mesh sheet (MNMS) to be a promising candidate of intracorporal topical hemostasis device that replace tissue-derived biomaterial to avoid a latently risk of infection. However, the MNMS, made with poly lactic acid (PLA), was required to improve its poor adhesion to soft tissue. Here we focused on North American porcupines’ specialized barbs from a biomimetic point of view. The geometry of the barbs enables easy penetration and superior tissue adhesion. In this study, inspired by the barbs of North American porcupine, we developed a MNMS as an artificial tunica media made with biodegradable material to replace Bio glue in cardiovascular surgeries. The geometry of the supporting structure of the microneedles was designed to be compliant enough to fit soft tissue. The master mold of the MNMS was designed and modeled on a 3D CAD software (Fusion 360, Autodesk), and printed by an ultra-high resolution SLA 3D printer (SONIC MINI 8K, phrozen). A negative mold of the photocurable resin microstructure was obtained by silicone elastomer (Sylgard 184, Dow Corning) casting. A PLA mesh sheet with specialized mesh pattern was printed by using a FDM 3D printer (Pro2, RAISE). The final product, MNMS of PLA, was formed by heat imprinting of the PLA mesh sheet onto the elastomer female mold that has the microneedles and supporting structure relief pattern. Adhesive properties of MNMSs to Parafilm was examined by 90° peel test. As a result, the biomimetic geometry of the microneedle, inspired by the barbs of North American porcupine, improved the MNMS adhesion to parafilm up 70%. These findings should serve as the basis for the development of biodegradable MNMS to replace Bio glue in cardiovascular surgeries.
Keywords: Type A aortic dissection, Artificial tunica media, Biodegradable microneedle.
