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Bio-Design and Manufacturing (2021) 4:432–439
Biofabrication (3D Bioprinting) Laboratory at Sichuan University
Changchun Zhou1,2 ·Kefeng Wang1,2 ·Yong Sun1,2 ·Qiguang Wang1,2 ·Qing Jiang1,3 ·Jie Liang1,2 ·
Xuan Pei1,2 ·Boqing Zhang1,2 ·Yujiang Fan1,2 ·Xingdong Zhang1,2
Received: 26 October 2020 / Accepted: 17 November 2020 / Published online: 3 January 2021
© Zhejiang University Press 2021
Introduction and research overview
Recently, increasing need for organ transplantation and lack
of donated organs have led to the rapid development of new
technologies for artificial organ biofabrication. In the era
of burgeoning breakthroughs around 3D bioprinting tech-
nologies, the personalization of organs and medicine is an
ongoing nice vision [15]. As one of the leading laborato-
ries in the interdisciplinary field of materials, manufacturing
and bioengineering, the Biofabrication (3D Bioprinting)
Research Laboratory at Sichuan University has been engag-
ing in the research on customized regenerative medicine since
BYujiang Fan
Changchun Zhou
Kefeng Wang
Yong Sun
Qiguang Wang
Qing Jiang
Jie Liang
Xuan Pei
Boqing Zhang
Xingdong Zhang
1National Engineering Research Center for Biomaterials,
Sichuan University, Chengdu 610064, China
2College of Biomedical Engineering, Sichuan
University, Chengdu 610064, China
3College of Materials Science and Engineering, Sichuan
University, Chengdu 610064, China
As a newly established research institute, the labora-
tory mostly focuses on regenerative biomedical engineering
research, particularly on bone tissue-inducing biomaterials.
Tissue-inducing biomaterial was officially defined as “a bio-
material designed to induce the regeneration of damaged or
missing tissues or organs without the addition of cells and/or
bioactive factors.” The definition of tissue-inducing bioma-
terial was firstly proposed by Professor Xingdong Zhang,
academic leader of our research center, and gained offi-
cial consent at the congress on Definitions of Biomaterials
for the Twenty-First Century, Elsevier, 2019. The ortho-
pedic regenerative biomaterial fabricated by our research
group is a successful tissue-inducing biomaterial belong-
ing in this research field. It can be traced back to 1980s.
Tissue-inducing biomaterial breaks through the traditional
conception that biomaterials cannot induce the regeneration
of tissues. Accordingly, it is our proposition that biofabri-
cation or 3D bioprinting technology could be applied to the
regeneration of personalized complex tissues.
Involved printing materials
The Biofabrication (3D Bioprinting) Research Laboratory
at Sichuan University attempts to innovative researches and
commercialization through the combination of engineering
and biomedicine. The purpose of the laboratory is to promote
the industrialization of technology and market operation, to
meet the needs of personalized biomedicine and treatment to
patients and to help to construct a harmonious and healthy
society. Up to now, the researches of the laboratory involved
3D printing of bioceramics, metal, polymers and their com-
posites. Some recent highlights are listed below.
3D printing of bioceramics
3D printing of bioceramics, especially the bioactive calcium
phosphate bioceramics, has drawn considerable attention in
recent years [68]. Bioceramics possess exceptional bio-
Bio-Design and Manufacturing (2021) 4:432–439 433
Fig. 1 Different 3D-printed calcium phosphate bioceramics. The cus-
tomized 3D-printed calcium phosphate bioceramics can be used for
maxillofacial bone repair, tumor bone defect filling, articular cup and
elbow bone replacement
compatibility and bioactivity with respect to bone cells and
tissues, due to their similarities to the chemical components
and mineral structure of the bone tissues. The calcium phos-
phate bioceramic is beneficial to biomineralization in bone
tissue regeneration. Up to now, bioceramics with different
structures, shapes and biological functions can be success-
fully printed. Studies are being conducted on the applications
of filling ceramic, cements, bearing bone substitute, compo-
nent materials, or coating on orthopedic implants. Calcium
phosphate powders (HA, β-TCP, BCP) formulated with dif-
ferent proportions can be used for printing ink configuration.
The scaffolds may be fabricated by either inkjet or DLP 3D
printing to obtain the porosity of 40–95%. The optimal pore
sizes ranging from 150 μm to 800 μm were recognized for
bone tissue growth and reconstruction. It has been proved in
our research that the 3D-printed calcium phosphate bioce-
ramic shows excellent osteoconduction and osteoinduction;
hence, it is a promising biomaterial for bone repair. Further-
more, the degradation rate of the bioceramic can be controlled
by adjusting the porous structure and the material composi-
tion, which may tailor the biodegradation rate to match the
growth rate of new bone regeneration [8]. Figure 1shows
different 3D-printed calcium phosphate bioceramics devel-
oped in our center, and some of them are successfully used
in clinic. These special biofunctional ceramics show advan-
tages in inducing bone tissue regeneration.
3D printing of metals
The ideal scaffold for bone tissue reconstruction should
resemble natural bones in both structural and mechanical
properties. Owing to its excellent mechanical properties and
biocompatibility, titanium alloy has been considered as the
best candidate for 3D printing of bone tissue implants. Selec-
tive laser melting (SLM) printer melts the selected area
of titanium powder directly to manufacture an object layer
by layer, so the object can be manufactured accurately [9,
10]. More importantly, SLM could produce highly compli-
cated implants with customized architectures for different
patients in accordance with their CT data. During model-
ing, with finite element analysis (FEA), the weakness of a
structure under pressure can be simulated so that the struc-
ture can be predesigned and optimized. In our center, SLM
technique was adopted to obtain precise porous titanium
implants with pore sizes of 400–1000 μm, exhibiting excel-
lent osseointegration performance in vivo. Novel porous
architectures, including cube structure, honeycomb struc-
ture and diamond-like structure, were designed for bionic
fabrication of load-bearing bone scaffolds. According to
studies, cortical bone exhibits elastic moduli and compressive
strengths within the ranges of 7–20 GPa and 100–250 MPa,
respectively, while in our study, the elastic modulus of the 3D-
printed scaffolds fabricated ranged from 1.19 to 5.14 GPa and
their compressive strength ranged from 36.76 to 139.97 MPa.
They conform to the requirements for biomimetic mechanics.
Studies have also been conducted on the removal of residual
metal powders, heat treatment and surface biological acti-
vation of titanium alloy. It is found that the surface of the
3D-printed scaffolds can be further modulated by surface
bioactivation to achieve favorable crystallinity and surface
morphology. Figure 2shows different 3D-printed porous tita-
nium scaffolds for bone tissue engineering.
3D printing of polymers and composites
Polymers can be easily printed and molded by various 3D
printing approaches. Complex scaffolds can be produced
according to 3D design files by decomposing an object’s
structures into a series of parallel slices. Then, the inter-
nal 3D structures are fabricated by reproducing these slices
one layer at a time by using a sized nozzle. For photocured
polymers, special photosensitive properties are required.
Fused deposition modeling (FDM) technique is one of the
most conventional and economical approaches; it is initially
used to rapidly fabricate polymer products with geomet-
ric shapes and dimensions [11,12]. FDM can be applied
to print many different polymers, such as PLA, PS, PEEK
and PCL. FDM technique has been adopted in fabricat-
ing polymer composites with different material components
and customized geometries. Figure 3shows different 3D-
printed polymers or polymer composites products prepared
in our previous researches. Our center fabricated PLA/HA
composites with enhanced osteogenic activity and mechan-
ical properties. By combining the comprehensive optimized
PLLA (L-polylactic acid)/nano-HA (nHA) composite with
the low-cost FDM technology, PLLA/nHA porous bone
tissue scaffold was achieved. The prepared PLLA/nHA
434 Bio-Design and Manufacturing (2021) 4:432–439
Fig. 2 Different 3D-printed
metal biomedical products.
These 3D-printed medical-grade
titanium or its alloys (Ti6Al4V)
are fabricated into various
biomimetic implants in terms of
mechanical and structural
properties, capable of being
used in human orthopedics, such
as femoral head nails or spinal
fusion devices. (a,c,d) Femoral
head nails and its porous
structure units (b); (e)3D
printed Ti6Al4V spinal fusion
products; (f) Samples of
different microporous structure
design; (g) Different designs of
intervertebral fusion cage
composite ink can secure the smooth and accurate print-
ing required for personalized bone repair application. The
PLLA/nHA composites scaffold has better mechanical prop-
erties and is free of the brittleness of porous bioceramics.
At the same time, the scaffold has been proved with better
osteogenic biological activity. PLA/HA composite scaffolds
are more similar to natural bone tissues in terms of struc-
ture, composition and mechanical compatibility than those
made of single ceramic or polymer materials. In addition,
3D bioprinting of cell-loaded polymers is another important
research hot spot, capable of endowing the scaffold with a
better biomimetic microenvironment and realizing precise
assembly of tissue or organ cells in the spatial structure. It
has been widely used in tissue regeneration and drug screen-
Major research directions
In the interdisciplinary field of 3D bioprinting, the main
research applications/directions in our laboratory are mainly
as follows:
Bionic design and analysis of advanced regenerative
Tissue engineering involves the use of porous scaffolds to
repair damaged biological tissues. The design and fabri-
cation of porous scaffold still remain major challenges in
bone tissue engineering. Hierarchical porous structures in
scaffold endow tissue regeneration with different biological
functions. Progresses in computational design and additive
manufacturing (AM) have resulted in quick and accurate
Fig. 3 Different 3D-printed polymers or polymer composites products.
These polymer-based 3D-printed products have been studied for surgi-
cal models, surgical guide plates, artificial auricle stent, vascular stent,
heart valve and so on. It shows good dimensional accuracy and mechan-
ical properties
3D printing of porous scaffolds with well-controlled bionic
architectures [13]. With thorough understanding of the struc-
ture of natural bone tissues, the personalized outer shape
of the implant can be constructed according to a patient’s
personalized medical image data, such as CT and MRI.
Based on the biomimetic natural bone trabeculae, a series of
biomimetic architectures have been proposed, such as cube
structure, honeycomb structure and diamond structure. With
finite element analysis, the structures’ weak points, optimal
pore size and spatial distribution can be simulated so that the
mechanical properties of the implants can be predesigned.
Internal architectures of tissue implants can be filled with
novel 3D porosity to achieve bionic design and manufac-
Bio-Design and Manufacturing (2021) 4:432–439 435
turing. In addition, foaming techniques are combined with
3D printing for achieving higher resolution and higher effi-
ciency of 3D printing. The potential and feasibility of these
combined 3D printing technology open door to the creation
of both macroscale porosity (100–1000 μm), 10–100 μm
and 1–10 μm micropores in bionic porous scaffolds [14].
Medical model and in vitro construction of diseased
Various medical models and diseased tissues or organs have
been fabricated by our research group. They could be used
for doctor–patient communication, medical teaching, surgi-
cal planning and so on. Additionally, these models help to
promote the design and preparation of customized prosthe-
sis. Since the medical models do not need to have excellent
biocompatibility as long as they can show personalized size
characteristics, conventional printing technologies can be
adopted, such as FDM and digital light procession (DLP).
Models of bones, ears, tumor tissues, heart, blood vessels,
etc., of specific patients can be well constructed in vitro.
Light curing resin is a good choice to print material in this
area (Fig. 4).
Load-bearing bone tissue regeneration implants
The repair of load-bearing bones and large defect bones is
still a challenge in orthopedics clinic. At present, 3D print-
ing technologies have been well tried [15,16]. For example,
clinical attempts have been made on the long spine, ver-
tebral body, and femur substitutes. For these applications,
biomechanical strength design, osseointegration with host
bone tissue and the ability to reconstruct new bones are
important issues need to be concerned. Studies have been
conducted on 3D printing of metal-based implants loaded
with active ingredients to promote bone integration, show-
ing a good osseointegration effect in vivo. And it is expected
to be used in spinal fusion cage.
Craniomaxillofacial biodegradable osteoinduction
Due to the diverse appearances of people, there are very
highly personalized requirements for craniomaxillofacial
bone tissue repair and reconstruction. 3D printing is a good
choice for this kind of application. In our laboratory, person-
alized modeling has been studied based on patients’ medical
image data and fabrication of customized implants using
biodegradable CaP bioceramics. With 3D printing of degrad-
able calcium phosphate ceramics, the new bone tissue can be
induced and the maxillofacial morphology can be well recon-
structed, with the biological functions well repaired.
Custom-made implants with specific biological
With 3D printing, customized products can be flexibly com-
posited and fabricated. By assembly of different components,
or filling implants loaded with drugs, custom-made implants
with specific biological functions can be fabricated. For
example, adding bioactive ingredients into printing inks,
or adsorbing drugs for controlled release has been tried to
achieve various biological functions, like promotion of vas-
cularization, anti-bacterial and anti-inflammatory functions
In vitro biofabrication of live tissue engineering
chips, organs and tissues
Biofabrication is considered as a cutting-edge research in
the emerging field of manufacture and biological systems.
This research involves biomaterials, living cells, proteins
and/or other biological compounds. They are used as basic
building blocks for the fabrication of biomimetic structures,
in vitro functional biological models and/or cellular systems
applied to tissue engineering, regenerative medicine, disease
pathogenesis, drug screening and tissue/organ chips. Biofab-
rication has great potential in drug screening, artificial organ
construction and so on. This cutting-edge research is under
way in our laboratories.
Biofabrication (3D Bioprinting) Research Laboratory is affil-
iated to National Engineering Research Center for Biomed-
ical Materials (NERB), Sichuan University. NERB is a
professional biomedical materials research and development
institution, which was founded by Ministry of Science and
Technology of China in 2000 as the first open national
biomedical materials research and development institution.
It integrates academic research, industry and production
of biomaterials or biomedical devices. The internationally
reputed NERB processes first-class engineering research
conditions and the innovation ability. The center was the
first company in China to research and develop hydroxyap-
atite (HA) ceramics and related synthetic bone grafts/dental
implants, and several biomedical products have been issued
by National Medical Products Administration, NMPA (it was
formerly known as the CFDA), with Registration Certificates
for Medical Devices. More than 20,000 implants were suc-
cessfully applied to patients. At present, we are promoting
the customization of personalized medical products based
on 3D printing technology. Biofabrication (3D Bioprint-
ing) Research Laboratory has different types of laboratories
for varied types of material printing, such as polymer 3D
436 Bio-Design and Manufacturing (2021) 4:432–439
Fig. 4 Bionic design and
analysis of advanced
regenerative biomaterials.
(a) Design of mandibular
prosthesis assembly model (top)
and products (below); (b)Pelvic
bone repair products; (c,f,g,
i) Biomimetic modeling, design
and mechanical strength
simulation process of spinal
fusion cage products, which
enable the realization of
pre-design analysis and surgical
assembly; (d,e) Spinal
microenvironment and
mechanical simulation; (h)3D
printed spinal fusion cage
Fig. 5 Laboratories and research
infrastructure of Sichuan
University Biofabrication
Research Laboratory.
(a) Polymer 3D bioprinting
room; (b) Ceramic 3D printing
room; (c) Metel 3D printing
room; (d) In vitro cell culture
room; (e) 3D biofabrication lab
bioprinting laboratory, ceramic 3D printing laboratory and
metal 3D printing laboratory (Fig. 5). These laboratories are
equipped with different printing facilities to meet the needs
of design and fabrication of different biomaterials. The 3D
printer facilities include polymer material extruder, fused
deposition modeling (FDM) printers, direct extrusion 3D
printer, cardiovascular 3D printer, low-temperature deposi-
tion printer, SLM metal 3D printer, bioceramics 3D printers,
cell 3D bioprinter, photocuring 3D printer, etc. (Figure 6).
These professional laboratories and research infrastructure
meet the requirements for the materials’ preparation, char-
acterization, biological testing and evaluation, including
in vitro cell experiments and in vivo animal experiments
(Fig. 7).
Bio-Design and Manufacturing (2021) 4:432–439 437
Fig. 6 Research infrastructure and 3D printers in Biofabrication
Research Laboratory at Sichuan University. The 3D printing devices
include: (a) polymer material extruder; (b) direct extrusion 3D printer,
Regenovo; (c) fused deposition modeling, FDM printers; (d) cardiovas-
cular 3D printer: EnvisionTEC; (e) low-temperature deposition printer:
SunP Biotech; (f) SLM metal 3D printer: Concept Laser; (g)3Dprinter
for bioceramics: ADMATEC; (h) cell 3D bioprinter: SunP Biomaker;
(i) photocuring 3D printer; (j) DLP ceramics printer
Fig. 7 Laboratories and research
infrastructure of Sichuan
University Biofabrication
Research Laboratory. The
images in top row (ac)arethe
in vitro cell culturing
laboratories, and the bottom row
images (dg) are the animal
experimental facilities
Fig. 8 (a) Group photographs of
professor Xingdong Zhang,
Academician of Chinese
Academy of Engineering, and
academic leader in our research
center. (b) Group photographs
of some PI professors and
students participated in the 3D
printing research
Combining the latest technologies in the field of 3D
printing and clinical medical needs, the Biofabrication (3D
Bioprinting) Research Laboratory is committed to improv-
ing patients’ personalized medical plans and providing better
health services. Figure 8shows the recent group photographs
of our research team, including some PI professors and stu-
dents participating in the 3D printing researches.
438 Bio-Design and Manufacturing (2021) 4:432–439
Our research work/projects have been sponsored by the
National Key Research and Development Program of China,
National Natural Science Foundation of China, Sichuan
Province Science & Technology Department Projects and
H2020-MSCA-RISE of European Union. To this date, the
center has published over 50 original research papers and
applied for over 30 patents in the area of 3D printing or
biofabrication of various novel biomaterials or biomedical
devices. Some authorized patents have been successfully
transformed into clinical production. Five patents belonging
to Changchun Zhou and Yujiang Fan et al. were evaluated by
a third evaluation party and priced at 16.9 million CNY. They
jointly established Chengdu Bainian Beiya Medical Technol-
ogy Co. Ltd. to promote personalized medical services for
patients and better realize the transformation and application
of 3D-printed orthopedic medical devices.
The center has undertaken a series of national research
projects and enjoys extensive cooperation and exchanges
with many domestic and overseas universities and research
institutions in this field, including Tsinghua University,
Zhejiang University, Shanghai Jiao Tong University, South
China University of Technology, Xi’an Jiaotong Univer-
sity, Huazhong University of Science and Technology, Bei-
hang University, Donghua University, Shanghai Institute of
Ceramics, Chinese Academy of Sciences, Shenzhen insti-
tutes of advanced technology, Chinese Academy of Sciences,
the European Society for Biomaterials, National Research
Council, Italy, etc. Meanwhile, we maintain close coop-
eration with more than 20 domestic first-class hospitals,
such as West China Hospital of Sichuan University, West
China Hospital of Stomatology Sichuan University, and
Southwest Hospital. We are collaborating in doing scien-
tific researches or biomedical products clinical trials. Due
to its good international influence and reputation, the Center
has been designated as the Innovation International Talents
Base (111 Base) by the Ministry of Education and the State
Administration of Foreign Experts of China. More than 10
universities and research institutions worldwide in the field
of biomaterials and 3D printing keep extensive international
collaborations and exchanges with our center.
The Biofabrication (3D Bioprinting) Research Laboratory
seeks to become a leading research center for medical scien-
tific researches and technology innovation. We are dedicated
to turning the center into a place well known for its merits
in scientific researches, engineering and medical excellence.
And we are working to create customized biomedical prod-
ucts benefiting the living generations and the generations
to come. As mentioned previously, our efforts are highly
directed toward researches on orthopedic repair biomaterials,
and plastic and cosmetic products. We are eager for further
innovation and development in this field.
Author contributions CZ and KW contributed to methodology, investi-
gation. YS, QW helped in writing and review. QJ, JL and XZ contributed
to conceptualization and funding acquisition. XP, BZ contributed to
original draft writing. YF contributed to supervision.
Compliance with ethical standards
Conflicts of interest There are no conflicts to declare.
Ethical approval The animal experiments were approved by the Animal
Care and Use Committee of Sichuan University. All applicable interna-
tional, national, and/or institutional guidelines for the care and use of
animals were followed.
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... Recently, additive manufacturing (AM) has made significant advances in biomedicine with the design, development, and fabrication of personalized medical implants-this underscores the potential of AM [1]. For example, the AM of customized porous Ti6Al4V scaffolds using selective laser melting (SLM) has been successfully developed at the Biofabrication Laboratory of Sichuan University [2] for human and veterinary clinical studies [3,4]. These 3Dprinted porous scaffolds are ideal for bone tissue engineering for bone osteointegration [5,6]. ...
... Dynamic Mechanical Analyzer (TA Instruments, Q-800, USA) was used to test the storage modulus and loss modulus of the GelMA hydrogel. The rheological properties of the GelMA hydrogel were analyzed by rheometer (MCR302, Anton Paar) (Zhou, 2021). ...
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Large-segment bone defect caused by trauma or tumor is one of the most challenging problems in orthopedic clinics. Biomimetic materials for bone tissue engineering have developed dramatically in the past few decades. The organic combination of biomimetic materials and stem cells offers new strategies for tissue repair, and the fate of stem cells is closely related to their extracellular matrix (ECM) properties. In this study, a photocrosslinked biomimetic methacrylated gelatin (Bio-GelMA) hydrogel scaffold was prepared to simulate the physical structure and chemical composition of the natural bone extracellular matrix, providing a three-dimensional (3D) template and extracellular matrix microenvironment. Bone marrow mesenchymal stem cells (BMSCS) were encapsulated in Bio-GelMA scaffolds to examine the therapeutic effects of ECM-loaded cells in a 3D environment simulated for segmental bone defects. In vitro results showed that Bio-GelMA had good biocompatibility and sufficient mechanical properties (14.22kPa). A rat segmental bone defect model was constructed in vivo . The GelMA-BMSC suspension was added into the PDMS mold with the size of the bone defect and photocured as a scaffold. BMSC-loaded Bio-GelMA resulted in maximum and robust new bone formation compared with hydrogels alone and stem cell group. In conclusion, the bio-GelMA scaffold can be used as a cell carrier of BMSC to promote the repair of segmental bone defects and has great potential in future clinical applications.
Three dimensional (3D) substrates based on natural and synthetic polymers enhance the osteogenic and mechanical properties of the bone tissue engineering scaffolds. Here, a novel bioactive composite scaffolds from polycaprolactone /kappa-carrageenan were developed for bone regeneration applications. 3D PCL scaffolds were fabricated by 3D printing method followed by coating with carboxymethyl kappa-carrageenan. This organic film was used to create calcium and strontium phosphate layers via a modified alternate soaking process in CaCl 2 /SrCl 2 and Na2HPO4 solutions in which calcium ions were replaced by strontium, with different amounts of strontium in the solutions. Various characterization techniques were executed to analyze the effects of strontium ion on the scaffold properties. The morphological results demonstrated the highly porous with interconnected pores and uniform pore sizes scaffolds. It was indicated that the highest crystallinity and compressive strength were obtained when 100% CaCl2 was replaced by SrCl2 in the solution (P-C-Sr). Incorporation of Sr onto the structure increased the degradation rate of the scaffolds. Mesenchymal stem cells (MSCs) culture on the scaffolds showed that Sr effectively improved attachment and viability of the MSCs and accelerated osteogenic differentiation as revealed by Alkaline phosphatase activity, calcium content and Real Time-Reverse transcription polymerase chain reaction assays.
Extracellular vesicles (EVs), products released by cells in multiple biological activities, are currently widely accepted as functional particles and intercellular communicators. From the orthodox perspective, EVs derived from apoptotic cells (apoEVs) are responsible for cell debris clearance, while recent studies have demonstrated that apoEVs participate in tissue regeneration. However, the underlying mechanisms and particular functions in tissue regeneration promotion of apoEVs remain ambiguous. Some molecules, such as caspases, active during apoptosis also function in tissue regeneration triggered by apoptosis,. ApoEVs are generated in the process of apoptosis, carrying cell contents to manifest biological effects, and possessing biomarkers to target phagocytes. The regenerative effect of apoEVs might be due to their abilities to facilitate cell proliferation and regulate inflammation. Such regenerative effect has been observed in various tissues, including skin, bone, cardiovascular system, and kidney. Engineered apoEVs are produced to amplify the biological benefits of apoEVs, rendering them optional for drug delivery. Meanwhile, challenges exist in thorough mechanistic exploration and standardization of production. In this review, we discussed the link between apoptosis and regeneration, current comprehension of the origination and investigation strategies of apoEVs, and mechanisms in tissue regeneration by apoEVs and their applications. Challenges and prospects are also discussed here.
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Plant-based hydrogels have attracted great attention in biomedical fields since they are biocompatible and based on natural, sustainable, cost-effective, and widely accessible sources. Here, we introduced new viscoelastic bio-inks composed of quince seed mucilage and cellulose nanofibrils (QSM/CNF) easily extruded into 3D lattice structures through direct ink writing in ambient conditions. The QSM/CNF inks enabled precise control on printing fidelity where CNF endowed objects with shape stability after freeze-drying and with suitable porosity, water uptake capacity, and mechanical strength. The compressive and elastic moduli of samples produced at the highest CNF content were both increased by ~100% (from 5.1 ± 0.2 kPa and 32 ± 1 kPa to 10.7 ± 0.5 and 64 ± 2 kPa, respectively). These values ideally matched those reported for soft tissues; accordingly, the cell compatibility of the printed samples was evaluated against HepG2 cells (human liver cancer). The results confirmed the 3D hydrogels as being non-cytotoxic and suitable to support attachment, survival, and proliferation of the cells. All in all, the newly developed inks allowed sustainable 3D bio-hydrogels fitting the requirements as scaffolds for soft tissue engineering.
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Jaw bone repair requires scaffold with bone regeneration, antibacterial function and personalized size. This study proposed 3D printed degradable calcium phosphate scaffolds with antibacterial functions for regeneration of jaw bone. Calcium phosphate powders and berberine were combined to modulate the printing inks. Porous scaffolds were fabricated by direct extrusion 3D printing and cross-linked with sodium alginate in situ. The dimensional size, shape and porosity of scaffolds were precisely customized by 3D printing. Berberine-loaded scaffolds show sustained release of antimicrobial drugs. By adjusting the concentration and cross-linking time of calcium chloride, the cross-linking degree of the scaffold can be adjusted and the drug load of the scaffold can be controlled. The young's modulus of 3DP scaffold was about 1.3 MPa. After freeze-drying, the shrinkage was about 24.4% and less swelling was observed, indicating that the scaffold had sufficient structural stability. In vitro biological test showed that the 3DP scaffold had low cytotoxicity and it was beneficial to MC3T3 cell adhesion and proliferation. 3D printed calcium phosphate scaffolds with controlled-release antibacterial properties is a promising biomaterials for jaw repair.
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The bone regenerative scaffold with the tailored degradation rate matching with the growth rate of the new bone is essential for adolescent bone repair. To satisfy these requirement, we proposed bone tissue scaffolds with controlled degradation rate using osteoinductive materials (Ca-P bioceramics), which is expected to present a controllable biodegradation rate for patients who need bone regeneration. Physicochemical properties, porosity, compressive strength and degradation properties of the scaffolds were studied. 3D printed Ca-P scaffold (3DS), gas foaming Ca-P scaffold (FS) and autogenous bone (AB) were used in vivo for personalized beagle skull defect repair. Histological results indicated that the 3DS was highly vascularized and well combined with surrounding tissues. FS showed obvious newly formed bone tissues. AB showed the best repair effect, but it was found that AB scaffolds were partially absorbed and degraded. This study indicated that the 3D printed Ca-P bioceramics with tailored biodegradation rate is a promising candidate for personalized skull bone tissue reconstruction.
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The macro architecture and micro surface topological morphology of implants play essential role in bone tissue regeneration. 3D printing technology provides enormous advantages for the rapid fabrication of personalized bone tissue repair implants. This study presents the demonstration of dual modulation 3D printed porous titanium implants to enhance the stability and osseointegration. Titanium implants with the first level of modulation on macro porous architecture and mechanical properties are obtained using macro architecture design and 3D printing fabrication. The first level of modulation achieved the scaffolds within a wide range of compressive strengths (36.76MPa - 139.97MPa) when varied the scaffolds' macro architectures. In the second level of modulation on surface topological morphology. Alkali treatment, heat treatments and electrochemical deposition of hydroxyapatite coating were conducted for further regulating on the biological function of implants. Dual modulation (DM) 3D printed scaffolds significantly promoted BMSCs adhesion and proliferation, indicating good cytocompatibility. In addition, in vivo osseointegration experiments displayed that the dual modulation scaffolds formed better tissue-materials interface. New bone formation rates in DM scaffolds are higher than those in the conventional 3D printed scaffolds after 6 months implantation (58.1% versus 36.1%). These results demonstrate that DM scaffolds could enhance the early stability and osseointegration. This study may provides new insights into the design, fabrication and post processing of 3D printing porous titanium implants for various applications in personalized bone tissue regeneration.
Scaffolds with a biomimetic hierarchy micro/nanoscale pores play an important role in bone tissue regeneration. In this study, multilevel porous calcium phosphate (CaP) bioceramic orthopedic implants were constructed to mimic the micro/nanostructural hierarchy in natural wood. The biomimetic hierarchical porous scaffolds were fabricated by combining three-dimensional (3D) printing technology and hydrothermal treatment. The first-level macropores (∼100-600 μm) for promoting bone tissue ingrowth were precisely designed using a set of 3D printing parameters. The second-level micro/nanoscale pores (∼100-10,000 nm) in the scaffolds were obtained by hydrothermal treatment to promote nutrient/metabolite transportation. Micro- and nanoscale-sized pores in the scaffolds were recognized as in situ formation of whiskers, where the shape, diameter, and length of whiskers were modulated by adjusting the components of calcium phosphate ceramics and hydrothermal treatment parameters. These biomimetic natural wood-like hierarchical structured scaffolds demonstrated unique physical and biological properties. Hydrophilicity and the protein adsorption rate were characterized in these scaffolds. In vitro studies have identified micro/nanowhisker coating as potent modulators of cellular behavior through the onset of focal adhesion formation. In addition, histological results indicate that biomimetic scaffolds with porous natural wood hierarchical pores exhibited good osteoinductive activity. In conclusion, these findings combined suggested that micro/nanowhisker coating is a critical factor to modulate cellular behavior and osteoinductive activity.
Biofabrication of personalized titanium scaffold mimicking that of the osteocyte microenvironment is challenging due to its complex geometrical cues. The effect of scaffolds geometrical cues and implantation sites on osteogenesis is still not clear. In this study, personalized titanium scaffolds with homogeneous diamond-like structures mimicking that of the osteocyte microenvironment were precisely designed and fabricated by selected laser melting method. The effects of different geometric cues, including porosity, pore sizes and interconnection properties, on cellular behavior were investigated. Biomimetic mechanical properties of porous titanium alloy scaffold were predesigned and simulated by finite element analysis. In vitro experiment revealed that homogeneous diamond-like structures mimicking that of the osteocyte microenvironment triggered osteocyte adhesion and migration behavior. Typical implantation sites, including rabbit femur, beagle femur, and beagle skull, were used to study the implantation sites effects on bone regeneration. In vivo experimental results indicated that different implantation sites showed significant differences. This study helps to understand the scaffolds geometrical microenvironment and implantation sites effects on osteogenesis mechanism. And it is beneficial to the development of bone implants with better bone regeneration ability.
Customized scaffold plays an important role in bone tissue regeneration. Precise control of the mechanical properties and biological functions of scaffolds still remains a challenge. In this study, metal and ceramic biomaterials are composited by direct 3D printing. HA powders with diameter of about 25 μm and Ti-6Al-4V powders with diameter of 15-53 μm were mixed and modulated for preparing 3D printing inks formulation. Three different proportions of 8wt.%, 10wt.% and 25wt.% HA specimens were printed with same porosity of 72.1%. The green bodies of the printed porous scaffolds were sintered at 1150 °C in the atmosphere of argon furnace and conventional muffle furnace. The porosities of the final 3D printed specimens were 64.3±0.8% after linear shrinkage of 6.5±0.8%. The maximum compressive strength of the 3D printed scaffolds can be flexibly customized in a wide range. The maximum compressive strength of these scaffolds in this study ranged from 3.07 MPa to 60.4 MPa, depending on their different preparation process. The phase composition analysis and microstructure characterization indicated that the Ti-6Al-4V and HA were uniformly composited in the scaffolds. The cytocompatibility and osteogenic properties were evaluated in vitro with rabbit bone marrow stromal cells (rBMSCs). Differentiation and proliferation of rBMSCs indicated good biocompatibility of the 3D printed scaffolds. The proposed 3D printing of Ti-6Al-4V/HA composite porous scaffolds with tunable mechanical and biological properties in this study is a promising candidate for bone tissue engineering.