3D Bioplotter Research Papers

Infection is one of the pivotal causes of nonunion in large bone defect after trauma or tumor resection. Three-dimensional (3D) composite scaffold with multifunctional-therapeutic properties offer many advantages over allogenic or xenogenic bone grafting for the restoration of challenging infected bone defects. In the previous study, we demonstrated that quaternized chitosan (HACC)-grafted polylactide-co-glycolide (PLGA)/hydroxyapatite (HA) scaffold (PLGA/HA/HACC) via 3D-printing technique exhibited significantly improved antimicrobial and osteoconductive property in vitro, together with good biocompatibility in vivo. Hence, the present study further investigated whether such an innovative bone substitute could effectively inhibit the bacterial biofilm formation and promote bone regeneration in vivo.…

Contaminated or infected bone defects remain serious challenges in clinical trauma and orthopaedics, and a bone substitute with both osteoconductivity and antibacterial properties represents an improvement for treatment strategy. In this study, quaternized chitosan (hydroxypropyltrimethyl ammonium chloride chitosan, HACC) was grafted to 3D-printed scaffolds composed of polylactide-co-glycolide (PLGA) and hydroxyapatite (HA), in order to design bone engineering scaffolds endowed with antibacterial and osteoconductive properties. We found that both the PLGA/HA/HACC and PLGA/HACC composite scaffolds decreased bacterial adhesion and biofilm formation under in vitro and in vivo conditions. Additionally, ATP leakage assay indicated that immobilizing HACC on the scaffolds could effectively…

Creating tissue and organ equivalents with intricate architectures and multiscale functional feature sizes is the first step toward the reconstruction of transplantable human tissues and organs. Existing embedded ink writing approaches are limited by achievable feature sizes ranging from hundreds of microns to tens of millimeters, which hinders their ability to accurately duplicate structures found in various human tissues and organs. In this study, a multiscale embedded printing (MSEP) strategy is developed, in which a stimuli-responsive yield-stress fluid is applied to facilitate the printing process. A dynamic layer height control method is developed to print the cornea with a smooth…

Light-based three-dimensional (3D) bioprinting has been widely studied in tissue engineering. Despite the fact that free-radical chain polymerization-based bioinks like hyaluronic acid methacrylate (HAMA) and gelatin methacryloyl (GelMA) have been extensively explored in 3D bioprinting, the thiol–ene hydrogel system has attracted increasing attention for its ability in building hydrogel scaffolds in an oxygen-tolerant and cell-friendly way. Herein, we report a superfast curing thiol–ene bioink composed of norbornene-modified hyaluronic acid (NorHA) and thiolated gelatin (GelSH) for 3D bioprinting. A new facile approach was first introduced in the synthesis of NorHA, which circumvented the cumbersome steps involved in previous works. Additionally, after…

Excellent electrical performance of assemblies of 1D silver nanowires (AgNWs) has been demonstrated in the past years. Up to now, however, there are limited approaches to realize simultaneously deterministic assembly with dense arrangement of AgNWs and desired functional layouts. Herein, an assembly strategy from compressed air-modulated alignment of AgNWs to heterogeneous integration of stretchable sensing devices through printing transfer is proposed. In this process, a convective flow induced by compressed air brings the AgNWs to the air–droplet interface, where the AgNWs are assembled with excellent alignment and packing due to the surface flow, van der Waals, and capillary interactions. Compared…

Articular cartilage tissue engineering is being considered an alternative treatment strategy for promoting cartilage damage repair. Herein, we proposed a modular hydrogel-based bioink containing microsphere-embedded chondrocytes for 3D printing multiscale scaffolds integrating the micro and macro environment of the native articular cartilage. Gelatin methacryloyl (GelMA)/alginate microsphere was prepared by a microfluidic approach, and the chondrocytes embedded in the microspheres remained viable after being frozen and resuscitated. The modular hydrogel bioink could be printed via the gel-in-gel 3D bioprinting strategy for fabricating the multiscale hydrogel-based scaffolds. Meanwhile, the cells cultured in the scaffolds showed good proliferation and differentiation. Furthermore, we also found that…

Recent studies on osteosarcoma and matrix stiffness are still mostly performed in a 2D setting, which is distinct from in vivo conditions. Therefore, the results from the 2D models may not reflect the real effect of matrix stiffness on cell phenotype. Here, we employed a 3D bioprinted osteosarcoma model, to study the effect of matrix stiffness on osteosarcoma cells. Through density adjustment of GelMA, we constructed three osteosarcoma models with distinct matrix stiffnesses of 50, 80, and 130 kPa. In this study, we found that osteosarcoma cells proliferated faster, migrated more actively, had a more stretched morphology, and a lower…

Surgery is the most frequent treatment for patients with brain tumors. The construction of full-scale human brain models, which is still challenging to realize via current manufacturing techniques, can effectively train surgeons before brain tumor surgeries. This paper aims to develop a set of three-dimensional (3D) printing approaches to fabricate customized full-scale human brain models for surgery training as well as specialized brain patches for wound healing after surgery. First, a brain patch designed to fit a wound’s shape and size can be easily printed in and collected from a stimuli-responsive yield-stress support bath. Then, an inverse 3D printing strategy,…

Polymer blend system has been commonly applied in a wide variety of applications. Herein, we propose to introduce sugar particles to polymer matrix, which results in a controllable polymer swelling under the action of osmotic pressure upon soaking in water. Taking advantage of this economic and environment-friendly, water-induced polymer swelling process, we have fabricated wrinkled conductive films and 3D structures by depositing conductive materials on the swollen polymer substrates for stretchable strain sensing devices. Several commercial silicone elastomers were utilized in the study. Key processing factors affecting the polymer swelling were investigated, including film thickness, sugar concentration, and temperature of…

As an engineering frontier, highly stretchable sensors are widely applied in many fields, such as human motion detection, personal healthcare monitoring, and human-machine interactions. In this study, novel silver nanowire (AgNW)-based stretchable sensors with hierarchical wrinkled structures were fabricated through a two-step process, namely water-induced swelling and AgNW deposition. As highly soluble additives, sodium chloride particles were incorporated into the elastomer matrix. Upon soaking in dopamine aqueous solution, significant swelling was introduced onto the elastomer substrate. The dopamine deposition is accompanied with the swelling process, which endows the sample surface with ultra-hydrophilicity. Additionally, the dopamine-modified swollen samples “capture” the nanowires…

3D Bioprinting plays an irreplaceable role in bone tissue engineering. Shellac and curcumin are two natural compounds that are widely used in the food and pharmaceutical sectors. In this study, a new composite scaffold with good biocompatibility and antibacterial ability was manufactured by adding shellac and curcumin into the traditional bone scaffold through low-temperature three-dimensional printing (LT-3DP), and its impact on the osteoimmune microenvironment was evaluated.

High-density polyethylene (HDPE) is a promising material for the development of scaffold implants for auricle reconstruction. However, preparing a personalized HDPE auricle implant with favorable bioactive and antibacterial functions to promote skin tissue ingrowth is challenging. Herein, we present 3D-printed HDPE auricle scaffolds with satisfactory pore size and connectivity. The layer-by-layer (LBL) approach was applied to achieve the improved bioactive and antibacterial properties of these 3D printed scaffolds. The HDPE auricle scaffolds were fabricated using an extrusion 3D printing approach, and the individualized macrostructure and porous microstructure were both adjusted by the 3D printing parameters. The polydopamine (pDA) coating method…

Current in vitro models for osteosarcoma investigation and drug screening, including two-dimensional (2D) cell culture and tumour spheroids (i.e. cancer stem-like cells), lack extracellular matrix (ECM). Therefore, results from traditional models may not reflect real pathological processes in genuine osteosarcoma histological structures. Here, we report a three-dimensional (3D) bioprinted osteosarcoma model (3DBPO) that contains osteosarcoma cells and shrouding ECM analogue in a 3D frame. Photo-crosslinkable bioinks composed of gelatine methacrylamide and hyaluronic acid methacrylate mimicked tumour ECM. We performed multi-omics analysis, including transcriptomics and DNA methylomics, to determine differences between the 3DBPO model and traditional models. Compared with 2D models…

Yield-stress support bath-enabled three-dimensional (3D) printing has been widely used in recent years for diverse applications. However, current yield-stress fluids usually possess single microstructures and still face the challenges of on-demand adding and/or removing support bath materials during printing, constraining their application scope. This study aims to propose a concept of stimuli-responsive yield-stress fluids with an interactive dual microstructure as support bath materials. The microstructure from a yield-stress additive allows the fluids to present switchable states at different stresses, facilitating an embedded 3D printing process. The microstructure from stimuli-responsive polymers enables the fluids to have regulable rheological properties upon external…

Massive oral and maxillofacial bone defect regeneration remains a major clinical challenge due to the absence of functionalized bone grafts with ideal mechanical and proregeneration properties. In the present study, Laponite (LAP), a synthetic nanosilicate, is incorporated into polycaprolactone (PCL) to develop a biomaterial for bone regeneration. It is explored whether LAP-embedded PCL would accelerate bone regeneration by orchestrating osteoblasts to directly and indirectly induce bone regeneration processes. The results confirmed the presence of LAP in PCL, and LAP is distributed in the exfoliated structure without aggregates. Incorporation of LAP in PCL slightly improved the compressive properties. LAP-embedded PCL is…

Controlled release of drugs from medical implants is an effective approach to reducing foreign body reactions and infections. We report here on a one-step 3D printing strategy to create drug-eluting polymer devices with a drug-loaded bulk and a drug-free coating. The spontaneously formed drug-free coating dramatically reduces the surface roughness of the implantable devices and serves as a protective layer to suppress the burst release of drugs. A high viscosity liquid silicone that can be extruded based on its shear-thinning property and quickly vulcanize upon exposure to ambient moisture is used as the ink for 3D printing. S-Nitrosothiol type nitric…

The potential translation of bio-inert polymer scaffolds as bone substitutes is limited by the lack of neovascularization upon implantation and subsequently diminished ingrowth of host bone, most likely resulted from the inability to replicate appropriate endogenous crosstalk between cells. Human umbilical vein endothelial cell-derived decellularized extracellular matrix (HdECM), which contains a collection of angiocrine biomolecules, has recently been demonstrated to mediate endothelial cells(ECs) – osteoprogenitors(OPs) crosstalk. We employed the HdECM to create a PCL (polycaprolactone)/fibrin/HdECM (PFE) hybrid scaffold. We hypothesized PFE scaffold could reconstitute a bio-instructive microenvironment that reintroduces the crosstalk, resulting in vascularized bone regeneration. Following implantation in a…

Flexible and stretchable conductors are crucial components for next-generation flexible devices. Wrinkled structures often have been created on such conductors by depositing conductive materials on the pre-stretched or organic solvent swollen samples. Herein, water swelling is first proposed to generate the wrinkled structures on silicone elastomers. By immersing silicone/sugar hybrid in water, a significant amount of swelling occurs as a result of osmosis and capillary interactions with the sugar and silicone matrix. Considering the drastic swelling effect and controllable swelling ratio, water swelling is used to replace the conventional pre-stretching and organic solvent swelling to fabricate stretchable conductors. In situ…

Osteocytes, essential regulators of bone homeostasis, are embedded in the mineralized bone matrix. Given the spatial arrangement of osteocytes, bioprinting represents an ideal method to biofabricate a 3D osteocyte network with a suitable surrounding matrix similar to native bone tissue. Here, we reported a 3D bioprinted osteocyte-laden hydrogel for biomimetic mineralization in vitro with exceptional shape fidelity, a high cell density (107 cells per ml) and high cell viability (85–90%). The bioinks were composed of biomimetic modified biopolymers, namely, gelatine methacrylamide (GelMA) and hyaluronic acid methacrylate (HAMA), with or without type I collagen. The osteocyte-laden constructs were printed and cultured…

In the present work, dissolved cellulose has been 3D bioprinted to produce complex structures with ordered interconnected pores. The process consists of the dissolution of dissolving pulps in N-methylmorpholine-N-oxide (NMMO), multilayered dispensing, water removal of NMMO and freeze-drying. 3D bioprinting of cellulose/NMMO solution at 70 ℃ was analogous to that of thermoplastics by the process of melting and solidification to produce cellulose/NMMO objects in the solid form. However, 3D bioprinting of cellulose/NMMO solution at a higher temperature than 70 ℃ produced cellulose/NMMO objects in the gel form. Cellulose was regenerated by water; thereafter, freeze-drying treatment maintained the 3D bioprinted structures…