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The characteristics of six materials [acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), thermoplastic polyurethane (TPU), polyvinyl alcohol (PVA), polyethylene terephthalate glycol (PETG), and polycarbonate (PC)] were tested in 3D-printed trimalleolar fracture models and compared under different conditions. A corresponding L9 (34) orthogonal array was applied to optimize the printing parameters. The printing time, weight, cost, surface roughness, height, support removal time, mechanical properties, and sterilization of models printed with the six materials were recorded. Both doctors and patients evaluated the models. ABS models had the shortest printing time, lightest weight, lowest cost, shortest time of removal support structure and best accuracy. PLA models soon fractured during loading compression force. TPU models had the heaviest weight and longest time of removal support structure, least compression force, largest deformation. PVA models had the longest printing time and highest cost. PETG models were the least accurate. PC models can load more compression strength. PLA and TPU maintained shape after sterilization; however, ABS, PVA, PC, and PETG deformed during sterilization. Patients preferred the PLA and 1:1 scale model, whereas doctors preferred the TPU and 80% scale models. Based on orthogonal experiments, printing parameters were comprehensively balanced to provide an important basis for printing models with different purposes in orthopedics. [ABSTRACT FROM AUTHOR]

In this paper, ZnO nanobelts have been partially high-quality synthesized employing diverse reactant mass ratios between zinc acetate [Zn(AC)2] and polyvinyl alcohol (PVA) without any catalyst. The maximum temperature required for the whole reaction process is no more than 650C. The morphologies of ZnO nanomaterials fabricated from distinct reactant concentrations have been systematically investigated by means of field-emission scanning electron microscopy (FESEM). X-ray diffraction (XRD) analysis identifies that ZnO nanobelts exhibit a typical wurtzite structure. Through fluorescence spectrometer, the photoluminescence (PL) spectra generated by ZnO nanomaterials corresponding to different reactant concentrations have disparate peak intensities and luminescence wavelengths. This phenomenon indicates that novel-synthesized ZnO nanomaterial shows great potential in changing the optical properties of light-emitting devices. In addition, synthetic ZnO nanobelts exhibit excellent UV emission capability. [ABSTRACT FROM AUTHOR]

In this study, ZnO nanobelts were successfully fabricated by flash synthesis without any expensive catalyst at a relatively low temperature (600C). The whole process took just 30 min. Introducing a solution tank containing a mixture of polyvinyl alcohol (PVA) and Zn(AC)2, was an auxiliary process to elevate the quality of the products. The morphology of the ZnO nanobelts was systematically investigated by means of field emission scanning electron microscopy (FRSEM) and high-resolution transmission electron microscopy (HRTEM). The products had an average width of 200nm and a length of more than 10. X-ray diffraction analysis indicated that the ZnO nanobelts had a typical wurtzite structure. Finally, the growth mechanism of the unique morphology of the ZnO nanobelts is discussed. An assembly-line production method is also proposed based on the results. [ABSTRACT FROM AUTHOR]

Large, deep, complex, and severe tissue defects and deformities of the face are the problems encountered in clinical practice. Autologous tissue reconstruction or allograft face transplantation has been adopted but has problems such as blood supply difficulties, collateral damage, immune rejection, and ethical disputes. 3D bioprinting enables personalized tissue regeneration. However, simple hydrogels are prone to collapse during printing, are limited in size, and have poor shape and structure. The present study used three polysaccharide hydrogel composites of nanocellulose, agarose, and sodium alginate with seeded cells as bioinks and polyvinyl alcohol (PVA) as sacrificial material to construct the structures that did not collapse (characteristic parts, such as lips and nose). The nutrient network gradually formed a blood vessel-like structure. The hydrogels prepared using these three polysaccharides have great potential in the construction of personalized, complex, and vascularized tissue-engineered anatomical faces and provide a new strategy for autologous full face reconstruction. • Polysaccharide composite hydrogels has more advantages in the field of bioprinting. • A strategy of constructing tissue engineering face-like structure was proposed. • It solves the problem of easy collapsing when printing pure hydrogel. [ABSTRACT FROM AUTHOR]

3D bioprinting represents a potential solution for organs regeneration, however, the production of complex tissues and organs that are in large size, randomly shaped, hollow, and contain integrated pre-vascularization still faces multiple challenges. This study aimed to test the feasibility of our 3D printing scheme for the manufacturing of micro-fluid channel networks complex three-dimensional tissue structures. The reverse engineering software was used to design the CAD model and polyvinyl alcohol (PVA) was used as the sacrificial material to print the sacrificial stent use the bioprinter nozzle 1. Hydrogel composite H9c2 and human umbilical vein endothelial cells (HUVECs) were mixed with sodium alginate, agarose solution and platelet-rich plasma (PRP) as cellular bioink, which was extruded through nozzle 2 to deposit the internal pores of the sacrificial scaffold. The scaffold dissolved, change to a flexible, hollow and micro-fluid channel networks complex structure. The 3D-bioprinting technology can construct a micro-fluid channel networks valentine heart with a self-defined height and hollow in suitable mechanical properties. The cells proliferate and maintain their biological properties within the printed constructs. This study demonstrates that valentine heart-like constructs can be fabricated with 3D bioprinting using sacrificial and hydrogel materials. In our study, we proposed a new method to facilitate the construction of large-size, hollow, and micro-fluid channel networks tissues or organs. The proposed method was tested via the construction of a hollow valentine-shaped heart. Image 1 • Engineered tissue with large-sized hollow, elastic and micro-fluid channel networks. • Preliminary construction of a arterial valve and a simplified anatomic hollow heart with multi-level fluid channels. • Micro-fluidic channels demonstrated the presence of endothelial vascularization. [ABSTRACT FROM AUTHOR]

Due to the unsatisfactory physicochemical properties of egg white proteins (EWPs), which limit their widespread application in wound dressings, we modified EWPs with graphene oxide (GO) due to excellent material properties. Egg white protein (EWP)/polyvinyl alcohol (PVA)/graphene oxide (GO) fibrous wound dressings with different GO concentrations (0, 0.5, 1, and 2 mg/ml) were produced by electrospinning, and their application potential in skin tissue repair was studied. The fabricated fibrous wound dressing was cross-linked and characterised, and hydrophilicity, degradation, water vapour transmission rate (WVTR), mechanical properties, antibacterial activity, cell compatibility and wound healing effect in vivo were measured. As the GO content increased, the spinnability of the mixed solution was reduced. FTIR and XRD confirmed that the GO, EWPs and PVA fibres were successfully combined. The addition of GO improved the antibacterial activity of the wound dressings. The overall performance of the EWP/PVA/GO wound dressing containing 1 mg/ml GO was optimal, displaying good hydrophilicity, degradation, WVTR, thermal stability, tensile mechanical properties, cell survival, and enhancing the proliferation, adhesion and migration of human dermal fibroblasts (HDFs) and human umbilical vein endothelial cells (HUVECs). In vivo healing experiments showed that the wound dressing containing 1 mg/ml GO promoted skin wound healing and tissue regeneration (type I collagen, vascularisation and hair follicle) the best. EWP/PVA/GO electrospun fibres with 1 mg/ml GO have great potential in wound dressing applications. [Display omitted] [ABSTRACT FROM AUTHOR]