3D Bioplotter Research Papers
Multi-material 3D printing of piezoelectric and triboelectric integrated nanogenerators with voxel structure
Flexible and highly filled piezoelectric nanogenerators with excellent performance play an indispensable role in portable electronic devices, while the bottlenecks are hard to improve the polarization efficiency and prepare three-dimensional (3D) amplifying effect structure. Compared with other typical 3D printing technologies, direct ink writing multi-material printing (DIW-M3D), can extrude multiple viscoelastic ink materials with a wide selection of materials, which has the advantage of integrated multi-material processing. However, there are fewer reports on the use of DIW-M3D technology to print functional composite materials. Inspired from Lego block structures, we utilized DIW-M3D technology to prepare fabrications with alternating arrangements of piezoelectric…
3D-printed tungsten sheet-gyroids via reduction and sintering of extruded WO3-nanopowder inks
Additive manufacturing of objects with complex geometries from refractory metals remains very challenging. Here, we demonstrate the fabrication of tungsten sheet-gyroids via 3D ink-extrusion of WO3 nano-powder followed by hydrogen reduction and activated sintering with NiO additions, as an alternative route to beam-based additive manufacturing of tungsten and other high melting metals and alloys. The microstructure and mechanical properties of the tungsten sheet-gyroids are measured for various wall architectures and processing conditions. The original gyroid architecture, separating two equally-sized volumes, is modified to achieve double-wall gyroids (with three separate volumes) with higher relative densities. The compressive properties of these single-…
Three-Dimensionally Printed Hyperelastic Bone Scaffolds Accelerate Bone Regeneration in Critical-Size Calvarial Bone Defects
Background: Autologous bone grafts remain the gold standard for craniofacial reconstruction despite limitations of donor-site availability and morbidity. A myriad of commercial bone substitutes and allografts are available, yet no product has gained widespread use because of inferior clinical outcomes. The ideal bone substitute is both osteoconductive and osteoinductive. Craniofacial reconstruction often involves irregular three-dimensional defects, which may benefit from malleable or customizable substrates. “Hyperelastic Bone” is a three-dimensionally printed synthetic scaffold, composed of 90% by weight hydroxyapatite and 10% by weight poly(lactic-co-glycolic acid), with inherent bioactivity and porosity to allow for tissue integration. This study examines the capacity of…
A Percolation Model for Piezoresistivity in Conductor–Polymer Composites
Insulating polymer composites with conductive filler particles are attractive for sensor applications due to their large piezoresistive response. Composite samples composed of a polymer matrix filled with particles of doped semiconductor that gives a piezoresistive response that is 105 times larger than that of bulk semiconductor sensors are prepared here. The piezoresistance of such composite materials is typically described by using a tunneling mechanism. However, it is found that a percolation description not only fits prior data better but provides a much simpler physical mechanism for the more flexible and soft polymer composite prepared and tested in this study. A…
NiTi-Nb micro-trusses fabricated via extrusion-based 3D-printing of powders and transient-liquid-phase sintering
We present a novel additive manufacturing method for NiTi-Nb micro-trusses combining (i) extrusion-based 3D-printing of liquid inks containing NiTi and Nb powders, solvents, and a polymer binder into micro-trusses with 0/90° ABAB layers of parallel, ∼600 µm struts spaced 1 mm apart and (ii) subsequent heat-treatment to remove the binder and solvents, and then bond the NiTi powders using liquid phase sintering via the formation of a transient NiTi-Nb eutectic phase. We investigate the effects of Nb concentration (0, 1.5, 3.1, 6.7 at.% Nb) on the porosity, microstructure, and phase transformations of the printed NiTi-Nb micro-trusses. Micro-trusses with the highest Nb content…
3D printed hyperelastic “bone” scaffolds and regional gene therapy: A novel approach to bone healing
The purpose of this study was to evaluate the viability of human adipose-derived stem cells (ADSCs) transduced with a lentiviral (LV) vector to overexpress bone morphogenetic protein-2 (BMP-2) loaded onto a novel 3D printed scaffold. Human ADSCs were transduced with a LV vector carrying the cDNA for BMP-2. The transduced cells were loaded onto a 3D printed Hyperelastic “Bone” (HB) scaffold. In vitro BMP-2 production was assessed using enzyme-linked immunosorbent assay analysis. The ability of ADSCs loaded on the HB scaffold to induce in vivo bone formation in a hind limb muscle pouch model was assessed in the following groups:…
Degradation behavior of polylactic-co-glycolic acid and polycaprolactone with nanosilver scaffolds
Ureteral stents are commonly used in clinical treatment of ureteral diseases. There were a series of complications, such as biofilms and crusts caused by bacteria after surgery. Therefore, biodegradable with bacteriostatic ureteral scaffolds would be the potential to solve above mentioned problems. In this study, nanosilver (AgNP) was added to the polylactic-co-glycolic acid (PLGA) and polycaprolactone (PCL) to prepare biodegradable antibacterial ureteral scaffold samples by 3D printing. The biocompatibility, antibacterial properties, degradability, and mechanical properties of samples were observed. The samples were under a strong inhibitory effect on both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), and the…
Porous bioceramic scaffolds based on akermanite obtained by 3D printing for bone tissue engineering
Porous bioceramic scaffolds were obtained by the 3D printing technique starting from a mixture of hydroxypropyl methyl cellulose and a powder obtained by sol-gel method which contains merwinite, monticellite, pseudowolastonie and periclase.The scaffolds were thermally treated at 1370 °C for 3 h and the main mineralogical compound assessed by XRD was akermanite. The obtained scaffolds have adequate mechanical and biological properties thus a great potential for applications in hard tissue engineering. The positive results obtained for this type of scaffolds are due to the precision of 3D printing technique, i.e. ability to control shape and size of both scaffolds and…
Development of a Nanohybrid Peptide Hydrogel for Enhanced Intervertebral Disc Repair and Regeneration
Effective therapeutic approaches to overcome the heterogeneous pro-inflammatory and inhibitory extracellular matrix (ECM) microenvironment are urgently needed to achieve robust structural and functional repair of severely wounded fibrocartilaginous tissues. Herein we developed a dynamic and multifunctional nanohybrid peptide hydrogel (NHPH) through hierarchical self-assembly of peptide amphiphile modified with biodegradable two-dimensional nanomaterials with enzyme-like functions. NHPH is not only injectable, biocompatible, and biodegradable but also therapeutic by catalyzing the scavenging of pro-inflammatory reactive oxygen species and promoting ECM remodeling. In addition, our NHPH method facilitated the structural and functional recovery of the intervertebral disc (IVD) after severe injuries by delivering pro-regenerative…
3D Printed Polyimide Nanocomposite Aerogels for Electromagnetic Interference Shielding and Thermal Management
Aerogels were listed among the top ten emerging technologies in chemistry by IUPAC in 2022. Their record-breaking properties sparked the emergence of a thriving insulation market, but solutions are sought to promote additional applications. A 3D assembly process based on direct ink writing of “aerogel-in-aerogel” nanocomposites is presented. The printed polyimide-silica aerogels are non-brittle (E = 6.7 MPa) with a super-insulating thermal conductivity (20.3 mW m−1 K−1) and high thermal stability (T5wt% 447 °C). In addition, they display excellent low-loss dielectric properties and microwave transmission over all relevant communication bands and can be functionalized for electromagnetic interference (EMI) shielding. The high shape-fidelity printing, combined…