Microarchitectured Carbon Structures as Innovative Tissue‐Engineering Scaffolds

Abstract

Additive manufacturing technologies have enabled some of the most relevant advances in the fields of tissue engineering and biofabrication, [1,2] thanks to the solid freeform fabrication opportunities they provide, which prove very adequate for achieving complex geometries capable of interacting in personalized ways with the human body. From pioneering studies dealing with the fused deposition modeling of tissue scaffolds as extracellular matrixes for cells, [3,4] to more recent bioprinting approaches, [5-7] which typically use layer-by-layer fabrication techniques with living organisms and biomaterials to produce complex tissues in vitro [8] (or use computer-aided transfer processes for patterning and assembling living and nonliving materials with a prescribed 2D or 3D organization to produce bio-engineered structures), [9] the possibility of manipulating matter in an additive way has proven transformative. However, additional progress is needed, as there is not yet a single additive manufacturing technique (AMT) that provides the perfect compromise between achievable part size, printing resolution, dimensional operative range, structural stability, and overall biocompatibility. For instance, syringe-based bioprinting techniques are still less precise than the more traditional AMTs working with synthetic materials, which are already a mainstream trend in biomedical engineering, medical practice, and biotechnology fields (i.e., selective laser sintering or melting of metallic powders, laser stereolithography with biophotopolymers or lithography-based ceramic manufacturing, among others). [10-12] Other biomanufacturing techniques, such as laser-assisted bioprinting has led to an improved precision level for manipulating living organisms and biomaterials, [13] and could possibly synergize with 3D lattices, used as boundaries or structural supports. This would help to minimize hydrogel creep and to achieve multi-scale and multi-material scaffolding structures with biomimetic functional gradients of mechanical properties. In contrast, the most precise additive manufacturing technologies, especially two-photon polymerization, which enables interactions even at single cellular level, [14] are not still adequate in terms of throughput and the overall building volume is normally limited to less than 1 mm 3. Furthermore, the materials used by most industrial AMTs, especially those relying on photopolymerization, are normally inadequate for implantation and, consequently, the achieved cell culture systems are limited to performing in vitro studies. In some cases, the use of carbon coatings (i.e., diamond-like carbon) upon laser stereolithography microsystems [15] or the use of carbon fibers knitted to 3D-printed

Electrospun carbon nanofibre-assisted patterning of metal oxide nanostructures

“…The stabilized electrospun AuCl 3 /PAN nanofibres were carbonized in a horizontal tube furnace (Carbolite Giro) to obtain the template AuNP/carbon nanofibres. The carbonization recipe used in our work was adapted from a process popularly used in carbon microelectromechanical systems (C-MEMS) technology 76 – 80 . Briefly, the process involved three steps: heating from room temperature to 900 °C with a heating rate of 5 °C min −1 , dwelling at 900 °C for 1 h, and cooling down to room temperature with natural cooling.…”

Fabrication of High Surface Area Microporous ZnO from ZnO/Carbon Sacrificial Composite Monolith Template

“…The ZnCl 2 /RF monolith was carbonized in a horizontal tube furnace. A typical carbonization recipe was used, as mentioned several times for the fabrication of carbon microelectromechanical (C-MEMS) devices [41][42][43][44][45]. Briefly, the furnace temperature was raised to 900 • C from room temperature with a heating rate of 5 • C/min, followed by a dwell at 900 • C for 2 h. An ambient cooling was implemented after the dwell at 900 • C.…”

'Nano-on-Micro' Approach Enables Synthesis of ZnO Nano-Cactus for Gas Sensing Applications

“…Furthermore, a peak at 2θ ¼ 30.6 was also observed in the XRD pattern, which can be indexed to the quartz substrate [37]. A bulge section was also observed in the XRD diffractogram in between 2θ ¼ 20 to 2θ ¼ 26 , which can be indexed to (002) reflection of turbostratic carbon [38,39]. This was attributed to the carbonization of the electrospun PAN fibers at high temperature.…”