The development of methods for the 3D printing of multifunctional devices could impact areas ranging from wearable electronics and energy harvesting devices to smart prosthetics and human–machine ...interfaces. Recently, the development of stretchable electronic devices has accelerated, concomitant with advances in functional materials and fabrication processes. In particular, novel strategies have been developed to enable the intimate biointegration of wearable electronic devices with human skin in ways that bypass the mechanical and thermal restrictions of traditional microfabrication technologies. Here, a multimaterial, multiscale, and multifunctional 3D printing approach is employed to fabricate 3D tactile sensors under ambient conditions conformally onto freeform surfaces. The customized sensor is demonstrated with the capabilities of detecting and differentiating human movements, including pulse monitoring and finger motions. The custom 3D printing of functional materials and devices opens new routes for the biointegration of various sensors in wearable electronics systems, and toward advanced bionic skin applications.
A multifunctional three‐dimensional (3D) printing approach is employed to fabricate 3D tactile sensors under ambient conditions conformally onto freeform surfaces. The sensors can detect and differente human motions, including pulse monitoring and finger movements. This custom 3D printing of functional materials and devices opens new routes toward the biointegration of various sensors in wearable electronic systems.
A bioengineered spinal cord is fabricated via extrusion‐based multimaterial 3D bioprinting, in which clusters of induced pluripotent stem cell (iPSC)‐derived spinal neuronal progenitor cells (sNPCs) ...and oligodendrocyte progenitor cells (OPCs) are placed in precise positions within 3D printed biocompatible scaffolds during assembly. The location of a cluster of cells, of a single type or multiple types, is controlled using a point‐dispensing printing method with a 200 µm center‐to‐center spacing within 150 µm wide channels. The bioprinted sNPCs differentiate and extend axons throughout microscale scaffold channels, and the activity of these neuronal networks is confirmed by physiological spontaneous calcium flux studies. Successful bioprinting of OPCs in combination with sNPCs demonstrates a multicellular neural tissue engineering approach, where the ability to direct the patterning and combination of transplanted neuronal and glial cells can be beneficial in rebuilding functional axonal connections across areas of central nervous system (CNS) tissue damage. This platform can be used to prepare novel biomimetic, hydrogel‐based scaffolds modeling complex CNS tissue architecture in vitro and harnessed to develop new clinical approaches to treat neurological diseases, including spinal cord injury.
A living platform to model spinal cord cytoarchitecture is introduced via 3D bioprinting, in which clusters of stem‐cell derived spinal neuronal progenitor cells and oligodendrocyte progenitor cells are placed in precise positions within biocompatible 3D printed scaffolds. The platform can ultimately be used as a therapeutic for chronic spinal cord injury to regenerate axons across the lesion site.
Conventional 3D printing technologies typically rely on open‐loop, calibrate‐then‐print operation procedures. An alternative approach is adaptive 3D printing, which is a closed‐loop method that ...combines real‐time feedback control and direct ink writing of functional materials in order to fabricate devices on moving freeform surfaces. Here, it is demonstrated that the changes of states in the 3D printing workspace in terms of the geometries and motions of target surfaces can be perceived by an integrated robotic system aided by computer vision. A hybrid fabrication procedure combining 3D printing of electrical connects with automatic pick‐and‐placing of surface‐mounted electronic components yields functional electronic devices on a free‐moving human hand. Using this same approach, cell‐laden hydrogels are also printed on live mice, creating a model for future studies of wound‐healing diseases. This adaptive 3D printing method may lead to new forms of smart manufacturing technologies for directly printed wearable devices on the body and for advanced medical treatments.
An adaptive 3D printing system capable of printing functional conductive inks and bioinks on moving freeform surfaces yields wireless electronics on a moving human hand and cell‐laden biostructures on mice. The concept of printing functional and biological materials via an autonomous, adaptive 3D printing system suggests a new paradigm for printing on‐the‐fly wearable electronics on moving targets and for surgical applications.
Neural regeneration devices interface with the nervous system and can provide flexibility in material choice, implantation without the need for additional surgeries, and the ability to serve as ...guides augmented with physical, biological (e.g., cellular), and biochemical functionalities. Given the complexity and challenges associated with neural regeneration, a 3D printing approach to the design and manufacturing of neural devices can provide next‐generation opportunities for advanced neural regeneration via the production of anatomically accurate geometries, spatial distributions of cellular components, and incorporation of therapeutic biomolecules. A 3D printing‐based approach offers compatibility with 3D scanning, computer modeling, choice of input material, and increasing control over hierarchical integration. Therefore, a 3D printed implantable platform can ultimately be used to prepare novel biomimetic scaffolds and model complex tissue architectures for clinical implants in order to treat neurological diseases and injuries. Further, the flexibility and specificity offered by 3D printed in vitro platforms have the potential to be a significant foundational breakthrough with broad research implications in cell signaling and drug screening for personalized healthcare. This progress report examines recent advances in 3D printing strategies for neural regeneration as well as insight into how these approaches can be improved in future studies.
3D printed platforms that combine cells, biomolecules, and scaffolds are growing in promise for combinatorial strategies in neural regeneration. This progress report focuses on the application of various 3D printing approaches to neuronal regeneration devices and mimicking the nervous system on a chip. Current challenges and future opportunities are highlighted to develop clinical implants to treat neurological diseases and injuries.
3D Printed Polymer Photodetectors Park, Sung Hyun; Su, Ruitao; Jeong, Jaewoo ...
Advanced materials,
08/2018, Letnik:
30, Številka:
40
Journal Article
Recenzirano
Odprti dostop
Extrusion‐based 3D printing, an emerging technology, has been previously used in the comprehensive fabrication of light‐emitting diodes using various functional inks, without cleanrooms or ...conventional microfabrication techniques. Here, polymer‐based photodetectors exhibiting high performance are fully 3D printed and thoroughly characterized. A semiconducting polymer ink is printed and optimized for the active layer of the photodetector, achieving an external quantum efficiency of 25.3%, which is comparable to that of microfabricated counterparts and yet created solely via a one‐pot custom built 3D‐printing tool housed under ambient conditions. The devices are integrated into image sensing arrays with high sensitivity and wide field of view, by 3D printing interconnected photodetectors directly on flexible substrates and hemispherical surfaces. This approach is further extended to create integrated multifunctional devices consisting of optically coupled photodetectors and light‐emitting diodes, demonstrating for the first time the multifunctional integration of multiple semiconducting device types which are fully 3D printed on a single platform. The 3D‐printed optoelectronic devices are made without conventional microfabrication facilities, allowing for flexibility in the design and manufacturing of next‐generation wearable and 3D‐structured optoelectronics, and validating the potential of 3D printing to achieve high‐performance integrated active electronic materials and devices.
Fully 3D‐printed polymer photodetectors are demonstrated on flexible substrates and hemispherical surfaces to integrate multidimensional image sensing arrays with high sensitivity and wide field of view. 3D printing multifunctional optoelectronic devices on a single platform is possible from a one‐pot, custom‐built extrusion‐based 3D manufacturing system. This work opens the possibility of the “off‐grid” printing of next‐generation wearable optoelectronic devices.
Resolution control and expansibility have always been challenges to the fabrication of structural color materials. Here, a facile strategy to print cholesteric liquid crystal elastomers (CLCEs) into ...complex structural color patterns with variable resolution and enhanced expansibility is reported. A volatile solvent is introduced into the synthesized CLC oligomers, modifying its rheological properties and allowing direct‐ink‐writing (DIW) under mild conditions. The combination of printing shear flow and anisotropic deswelling of ink drives the CLC molecules into an ordered cholesteric arrangement. The authors meticulously investigate the influence of printing parameters to achieve resolution control over a wide range, allowing for the printing of multi‐sized 1D or 2D patterns with constant quality. Furthermore, such solvent‐cast direct‐ink‐writing (DIW) strategy is highly expandable and can be integrated easily into the DIW of bionic robots. Multi‐responsive bionic butterfly and flower are printed with biomimetic in both locomotion and coloration. Such designs dramatically reduced the processing difficulty of precise full‐color printing and expanded the capability of structural color materials to collaborate with other systems.
A novel approach for producing cholesteric liquid crystal elastomers with vibrant structural colors using solvent‐cast direct‐ink‐writing is presented. By leveraging this scalable and versatile technique, the ability to create complex and intricate patterns, as well as bionic robots such as a butterfly and a flower, which are responsive to magnetic fields and thermal stimuli is demonstrated.
Surface‐correlated nanophase iron particles (npFe0) alter the reflectance spectrum characteristics of airless bodies, thus making it an essential aspect of studying space weathering. Vapor deposition ...has been the only strongly proven npFe0 formation mechanism owing to the long exposure time of Apollo samples, whereas other formation mechanisms remain questioned. Newly returned younger Chang'E‐5 samples provide an opportunity to study the incipient formation mechanism of npFe0. Here, we combined transmission electron microscopy and electron energy loss spectroscopy to characterize the microscopic features of Chang'E‐5 olivine rims. The uppermost layer of these grains exhibits the simultaneous coexistence of npFe0 with Si‐rich material overlying an Mg‐rich layer, as well as numerous irregular vesicles containing oxygen‐rich (SiO and O2) components embedded in the npFe0. These microscopic features collectively suggest subsolidus olivine decomposition during (micro)impact‐induced fragmentation or local heating processes, which may be the essential agent to alter the reflectance spectrum of airless bodies.
Plain Language Summary
Airless bodies experienced a space weathering modification to form the nanophase iron particles (npFe0) that would alter the reflectance spectrum. However, the formation mechanism of npFe0 remains controversial due to the lack of less‐exposed lunar samples to study the incipient information about npFe0 formation, except for the widely accepted vapor deposition origin. Our study is based on the younger Chang'E‐5 samples and report the first strong evidence of unique vesicular npFe0 produced by olivine decomposition under subsolidus conditions, which may be the first effect contributing to npFe0 formation on the lunar surface. This formation mechanism will shed light on the npFe0 production and further broaden the perspective of impact effects beyond the Moon and deepen the current understanding of unexplored celestial bodies using remote sensing.
Key Points
Subsolidus fayalitic olivine decomposition forming unique vesicular nanophase iron particles in Chang'E‐5 soils was confirmed
Nanophase iron particles in the uppermost olivine layer are embedded with numerous vesicles containing possible O2 or SiO component
Unique microstructural features on fayalitic olivine rims shed light on the diversity of space weathering effects on the lunar surface
A multifunctional 3D liquid sensor made of a PLA/MWCNT nanocomposite and shaped as a freeform helical structure was fabricated by solvent-cast 3D printing. The 3D liquid sensor featured a relatively ...high electrical conductivity, the functionality of liquid trapping due to its helical configuration, and an excellent sensitivity and selectivity even for a short immersion into solvents.
Rapid, simple, and cost-effective diagnostics are needed to improve healthcare at the point of care (POC). However, the most widely used POC diagnostic, the lateral flow immunoassay (LFA), is ...∼1000-times less sensitive and has a smaller analytical range than laboratory tests, requiring a confirmatory test to establish truly negative results. Here, a rational and systematic strategy is used to design the LFA contrast label (i.e., gold nanoparticles) to improve the analytical sensitivity, analytical detection range, and antigen quantification of LFAs. Specifically, we discovered that the size (30, 60, or 100 nm) of the gold nanoparticles is a main contributor to the LFA analytical performance through both the degree of receptor interaction and the ultimate visual or thermal contrast signals. Using the optimal LFA design, we demonstrated the ability to improve the analytical sensitivity by 256-fold and expand the analytical detection range from 3 log10 to 6 log10 for diagnosing patients with inflammatory conditions by measuring C-reactive protein. This work demonstrates that, with appropriate design of the contrast label, a simple and commonly used diagnostic technology can compete with more expensive state-of-the-art laboratory tests.
Synthesizing antiferromagnets with correlated oxides has been challenging, owing partly to the markedly degraded ferromagnetism of the magnetic layer at nanoscale thicknesses. Here we report on the ...engineering of an antiferromagnetic interlayer exchange coupling (AF-IEC) between ultrathin but ferromagnetic La2/3Ca1/3MnO₃ layers across an insulating CaRu1/2Ti1/2O₃ spacer. The layer-resolved magnetic switching leads to sharp steplike hysteresis loops with magnetization plateaus depending on the repetition number of the stacking bilayers. The magnetization configurations can be switched at moderate fields of hundreds of oersted. Moreover, the AF-IEC can also be realized with an alternative magnetic layer of La2/3Sr1/3MnO₃ that possesses a Curie temperature near room temperature. The findings will add functionalities to devices with correlated-oxide interfaces.
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