Center for Regenerative Medicine Research,
Saga University School of Medicine

佐賀大学医学部附属 再生医学研究センター

Scaffold-Free
Biofabrication
of Living Organs

Pioneering the Kenzan method — a robotic bioprinting technology that assembles living tissue constructs entirely from cells, without any artificial scaffolds. Saga University School of Medicine.

The Kenzan method: cells form spheroids, which are placed onto a microneedle array, fuse into continuous tissue, and are harvested as a scaffold-free construct
Note: There is another Koichi Nakayama at Saga University in Information Engineering. Please ensure you are contacting the correct laboratory.
*同姓同名に注意！
佐賀大学には同姓同名の中山功一教授（佐賀大学大学院 工学系研究科 知能情報システム学専攻）が在籍していますので書類等送付時は所属など宛先をご確認ください。
The Kenzan Method

How It Works

01

Spheroid Formation

Cells are cultured into uniform multicellular spheroids — the fundamental building blocks of our constructs.

02

Robotic Placement

A Bio-3D printer precisely skewers spheroids onto a microneedle array (Kenzan) according to a 3D design.

03

Fusion & Maturation

Spheroids fuse spontaneously through natural cell adhesion, forming a continuous living tissue.

04

Construct Harvest

The fused construct is removed from the needle array — entirely scaffold-free, made only from living cells.

Research Output

Publications

2026
Biofabrication strategies for engineered constructs in cardiovascular tissue repair
Yu J, Murata D, Itoh M, Nakayama K
Regenerative Therapy 32, 101110
2026
Extracellular Matrix Microspheres with Magnetically Labelled MSCs enable Functional Regeneration of the Osteo-Tendinous Junction
Datla A, Bairagya G, Nakayama K, Vadrevu S, Rath SN
ACS Appl. Mater. Interfaces 2026
2026
Modulation of iPSC-derived NCMSC cell state by TD-198946 enhances scaffold-free cartilage biofabrication
Nakamura A, Zujur D, Nonaka T, Yoshizato H, Kashimoto S, Ikeya M, Nakayama K
Biofabrication 18 025004
2026
A Scaffold-Free Cartilage Construct Fabricated Using a Bio 3D Printer Accelerates Critical-Size Bone Defect Regeneration
Yoshizato H, Murata D, Kashimoto S, Nonaka T, Fujimoto R, Nagaishi Y, Itoh M, Morimoto T, Nakayama K
J Orthopaedic Translation 57, 101033
2025
Xenograft of bio-3D printed scaffold-free cartilage constructs derived from human iPSCs to regenerate articular cartilage in immunodeficient pigs
Nonaka T, Murata D, Nakamura A, Yoshizato H, Kashimoto S, Nagaishi Y, Itoh M, Zujur D, Ikeya M, Toguchida J, Mawatari M, Nakayama K
Regenerative Therapy 29, 506–516
2025
Promotion of bone-tendon healing after ACL reconstruction using scaffold-free constructs comprising ADSCs produced by a bio-3D printer in rabbit models
Higa K, Murata D, Azuma C, Nishida K, Nakayama K
J Orthopaedic Translation 52, 265–275
2025
Bio-3D printing of scaffold-free ADSC-derived cartilage constructs comparable to natural cartilage in vitro
Nonaka T, Murata D, Yoshizato H, Kashimoto S, Nakamura A, Morimoto T, Nakayama K
J Orthop Surg Res 20, 182
2024
Fabrication of a Bio-3D Printed Scaffold-Free Artificial Trachea with Horseshoe-Shaped Hyaline Cartilage
Uchida F, Matsumoto K, Nishimuta M, et al.
European J Cardio-Thoracic Surgery 66(4)
2024
Nerve regeneration using a Bio 3D conduit derived from umbilical cord-derived mesenchymal stem cells
Iwai T, Aoyama T, Noguchi T, et al.
PLoS ONE 19(12):e0310711
2024
Creating 3D constructs with cranial neural crest-derived cell lines using a bio-3D printer
Taguchi M, Yoshimoto S, Suyama K, et al.
J Oral Biosciences 66(2), 339–348
2024
Three-Dimensional Bio-Printed Tubular Tissue Using Dermal Fibroblast Cells as a New Tissue-Engineered Vascular Graft
Hayasaka M, Kokudo T, Kaneko J, et al.
ASAIO Journal 70(11), 1008–1014
2024
Scaffold-free bone-like 3D structure established through osteogenic differentiation from human gingiva-derived stem cells
Toyoda M, Fukuda T, Fujimoto R, et al.
Biochemistry and Biophysics Reports 38, 101656
2023
Special Issue: Biofabrication with Spheroid and Organoid Materials Guest Editor
Skylar-Scott M, Declercq H, Nakayama K
Acta Biomaterialia 165
2023
Scaffold-free human vascular calcification model using a bio-three-dimensional printer
Nagaishi Y, Murata D, Yoshizato H, Nonaka T, Itoh M, Hara H, Nakayama K
Biofabrication 15(4)
2023
Enhanced chondrogenic differentiation of iPS cell-derived mesenchymal stem/stromal cells via neural crest cell induction
Zujur D, Al-Akashi Z, Nakamura A, et al.
Frontiers in Cell and Developmental Biology 11:1140717
2023
Regeneration of the ureter using a scaffold-free live-cell structure created with bio-three-dimensional printing
Takagi K, Taniguchi D, Machino R, et al.
Acta Biomaterialia 165, 102–110
2022
Scaffold-Free Tubular Engineered Heart Tissue From Human iPSCs Using Bio-3D Printing Technology In Vivo
Kawai Y, Tohyama S, Arai K, et al.
Frontiers in Cardiovascular Medicine 8:806215
2022
Nerve regeneration using the Bio 3D conduit fabricated with spheroids Review
Ikeguchi R, Aoyama T, Noguchi T, et al.
J Artificial Organs 25, 289–297
2022
Bio-3D printing of scaffold-free osteogenic and chondrogenic constructs using rat adipose-derived stromal cells
Fujimoto R, Murata D, Nakayama K
Front. Biosci. (Landmark Ed) 27(2), 052
2021
Kenzan Method for Scaffold-Free Biofabrication Book
Nakayama K (Ed.)
Springer Nature ISBN 978-3-030-58688-1
2021
Bio-3D printing iPSCs-derived human chondrocytes for articular cartilage regeneration
Nakamura A, Murata D, Fujimoto R, Tamaki S, Nagata S, Ikeya M, Toguchida J, Nakayama K
Biofabrication 13, 044103
2021
Scaffold-based and scaffold-free cardiac constructs for drug testing Review
Arai K, Kitsuka T, Nakayama K
Biofabrication 13, 042001
2021
Bile duct reconstruction using scaffold-free tubular constructs created by Bio-3D Printer
Hamada T, Nakamura A, Soyama A, et al.
Regenerative Therapy 16, 81–89
2020
Pro-angiogenic scaffold-free Bio 3D conduit from human iPSC-derived mesenchymal stem cells promotes peripheral nerve regeneration
Mitsuzawa S, Zhao C, Ikeguchi R, et al.
Scientific Reports 10, 12034
2020
Drug response analysis for scaffold-free cardiac constructs fabricated using bio-3D printer
Arai K, Murata D, Takao S, Nakamura A, Itoh M, Kitsuka T, Nakayama K
Scientific Reports 10, 8972
2020
Scaffold-free Bio-3D Printing using Spheroids as "Bio-inks" for Tissue (Re-)construction and Drug Response Tests Review
Murata D, Arai K, Nakayama K
Adv. Healthcare Mater. May 2020
2019
Development of an immunodeficient pig model allowing long-term accommodation of artificial human vascular tubes
Itoh M, Mukae Y, Kitsuka T, et al.
Nature Communications 10, 2244
2019
Replacement of Rat Tracheas by Layered, Trachea-like, Scaffold-free Structures of Human Cells Using Bio-3D Printing
Machino R, Matsumoto K, Taniguchi D, et al.
Adv. Healthcare Mater. 2019, 1800983
2019
Regeneration of esophagus using a scaffold-free biomimetic structure created with bio-three-dimensional printing
Takeoka Y, Matsumoto K, Taniguchi D, et al.
PLoS ONE 14(3):e0211339
2018
A definition of bioinks and their distinction from biomaterial inks Perspective
Groll J, Burdick JA, Cho D-W, ...Nakayama K, et al.
Biofabrication 11, 013001
2017
In vivo and ex vivo methods of growing a liver bud through tissue connection
Yanagi Y, Nakayama K, Taguchi T, et al.
Scientific Reports 7, 14085
2017
Principles of the "Kenzan" method for robotic cell spheroid-based three-dimensional bioprinting Review
Moldovan NI, Hibino N, Nakayama K
Tissue Engineering Part B: Reviews 23(3), 237–244
2016
Development of a three-dimensional pre-vascularized scaffold-free contractile cardiac patch for treating heart disease
Noguchi R, Nakayama K, Itoh M, et al.
J Heart and Lung Transplantation 35(1), 137–145
2015
Scaffold-free tubular tissues created by a Bio-3D printer undergo remodeling and endothelialization when implanted in rat aortae
Itoh M, Nakayama K, Noguchi R, et al.
PLoS ONE 10(9):e0136681
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Center for Regenerative Medicine Research
Faculty of Medicine, Saga University
5-1-1 Nabeshima, Saga City
Saga 849-8501, Japan

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