Page 141 - IJB-9-3

International Journal of Bioprinting Bioprinting tissue-engineered bone-periosteum biphasic complex.

1. Introduction Periosteum, which covers the most part of the bone, plays
a significant role in bone regeneration and homeostasis.
Critical-sized bone defects caused by trauma, infection, Periosteum is not only a highly vascularized tissue, but
tumor, and developmental deformities are difficult to also a reservoir of bone progenitor cells . Due to the lack
[10]
[1]
heal spontaneously . The treatment of critical-sized bone of periosteum, the repair effect of some bone grafts were
defects still remains as a major challenge in plastic and poor, and the natural periosteum could be directly used for
reconstructive surgery, and the current clinical treatments, bone repair . These remarkable effect of periosteum has
[11]
including bone grafts, distraction osteogenesis, and guided led to extensive research on the use of periosteum-derived
[2]
bone regeneration, often have limited effect . stem cells (PDSCs) for repairing critical-sized bone
Tissue engineering combined with scaffolds, stem defect . However, only a few studies have reported about
[12]
cells, and growth factors to repair the bone defects tissue-engineered periosteum constructs [13,14] . In fact, both
could effectively solve the problems of tissue shortage BMSCs and PDSCs are commonly used as the cell sources
and immune rejection caused by bone transplantation. for bone tissue engineering. It has also been reported
With the development of new biomaterials, stem cell that co-culturing human BMSCs and PDSCs could
biology, and three-dimensional (3D) biological printing produce synergistic effect on osteogenic differentiation .
[15]
technology, tissue engineering has broad prospects in Moreover, a growing number of studies have been focusing
the treatment of bone defects. Good research progress on using co-culture engineering system for effective repair
has been reported by many studies devoted to the of bone defect [16,17] . Here, we applied BMSCs and PDSCs to
exploration of tissue-engineered bone construction simulate the cellular components of bone and periosteum,
strategies. However, the traditional tissue engineering respectively, and to construct tissue-engineered bone-
technology is facing many problems, such as cell aging, periosteum biphasic complex on the basis of the co-culture
difficulty in inducing differentiation, poor material mode, hoping to solve the problem of large bone defects
properties, and bone reconstruction after absorption, from the perspective of physiological structure imitation.
which might not fulfill the requirements of large bone
[3]
defect repair . Three main components, which are Bioprinting is a 3D manufacturing technology for
considered important for bone tissue engineering, accurately distributing cell-loading biomaterials to
are osteoconductive scaffolds, osteogenic cells, and construct complex living tissues and artificial organs.
osteoinductive growth factors . An osteoconductive It has broad application prospects in the field of tissue
[4]
scaffold can not only simulate the structure and function engineering and regenerative medicine; however, it is
of extracellular matrix (ECM), but also provide effective challenging to construct tissues and organs with structural
[18,19]
mechanical support for adhesion, proliferation and integrity using bioprinting . Gelatin methacryl
differentiation of cells. As one of the main components (GelMA) hydrogel, which has been widely applied in
of bone tissue, hydroxyapatite (HA), which has pores to various biomedical situations, is similar to natural ECM
allow tissue in-growth, has been used as a high-quality and beneficial for the biological behavior of cells. Moreover,
bone substitute . All ceramic materials are brittle, it can be crosslinked under ultraviolet (UV) light to form
[5]
[20,21]
but using biodegradable polymer–ceramic composites hydrogel with adjustable mechanical properties . We
could improve biocompatibility and biomechanical intended to take advantages of bioprinting in mechanics,
[6]
properties . Poly-L-lactic acid (PLLA) is a kind of structure, and personalization, and a novel strategy of co-
biodegradable synthetic polymers that can be degraded culture bioprinting was proposed. GelMA loaded with
to lactic acid through the metabolic pathway similar BMSCs and PDSCs was used to simulate the ECM and cell
to the one in organisms. It has been safely used in components of bone and periosteum phase, respectively.
the clinical application of soluble sutures, intra-bone The bone-periosteum biphasic complex was constructed
[7]
implants, and soft tissue implants . In our study, we by combining PLLA/HA supporting scaffold, and the
mixed HA and PLLA to construct PLLA/HA scaffold, repair effect was evaluated from the perspective of imaging
and then studied the effect of different molecular weights and histology after repairing the critical-sized calvarial
and mixing ratios on the mechanical strength. With the defect of rabbit.
deepening research of stem cells, the study of stem cells- In summary, we designed and used the multinozzle
based regenerative medicine has drawn more public distribution modules of 3D bioprinter system to deposit
attention . As one of the ideal seed cells, bone marrow different cells-laden GelMA together with biosynthetic
[8]
mesenchymal stem cells (BMSCs) have been used in PLLA/HA scaffold to construct a tissue-engineered bone-
the treatment of various bone diseases . Therefore, we periosteum biphasic complex, and then evaluated the
[9]
applied BMSCs with osteogenic differentiation in the characteristics and functions of the constructed complex
construction of tissue-engineered bone. both in vitro and in vivo. Through this work, we hope to

Volume 9 Issue 3 (2023) 133 https://doi.org/10.18063/ijb.698