Transplantation of patient-specific bile duct bioengineered with chemically reprogrammed and microtopographically differentiated cells.

Cholangiopathy is a diverse spectrum of chronic progressive bile duct disorders with limited treatment options and dismal outcomes. Scaffold- and stem cell-based tissue engineering technologies hold great promise for reconstructive surgery and tissue repair. Here, we report a combined application of 3D scaffold fabrication and reprogramming of patient-specific human hepatocytes to produce implantable artificial tissues that imitate the mechanical and biological properties of native bile ducts.

Additive manufacturing of the core template for the fabrication of an artificial blood vessel: the relationship between the extruded deposition diameter and the filament/nozzle transition ratio.

An artificial blood vessel with a tubular structure was additively manufactured via fused deposition modeling (FDM) starting from a single strand of polyvinyl alcohol (PVA) filament coated with a specific thickness of biocompatible polydimethylsiloxane (PDMS), followed by removal of the inner core via hydrogen peroxide leaching under sonication. In particular, we examined the relationship between the extruded deposition diameter and the filament migration speed/nozzle control speed (referred to as the filament/nozzle transition ratio), which is almost independent of the extruded deposition flow rate due to the weak die-swelling and memory effects of the extruded PVA arising from its intrinsically low viscoelasticity. The chemical stability of the PDMS during sonication in the hydrogen peroxide solution was then determined by spectroscopic techniques.

3D bioprinted complex constructs reinforced by hybrid multilayers of electrospun nanofiber sheets.

Despite the usefulness of hydrogels for cell-based bioprinting, the fragility of their resulting constructs has hindered their practical applications in tissue engineering research. Here, we suggest a hybrid integration method based on cell-hydrogel bioprinting that includes alternate layering of flexible nanofiber (NF) sheets. Because the bioprinting was implemented on a nanofibrous surface, the hydrogel-based materials could be printed with enhanced shape resolution compared to printing on a bare hydrogel.

Detection of Stress Levels from Biosignals Measured in Virtual Reality Environments Using a Kernel-Based Extreme Learning Machine.

Virtual reality (VR) is a computer technique that creates an artificial environment composed of realistic images, sounds, and other sensations. Many researchers have used VR devices to generate various stimuli, and have utilized them to perform experiments or to provide treatment. In this study, the participants performed mental tasks using a VR device while physiological signals were measured: a photoplethysmogram (PPG), electrodermal activity (EDA), and skin temperature (SKT).

Design and Fabrication of a Thin-Walled Free-Form Scaffold on the Basis of Medical Image Data and a 3D Printed Template: Its Potential Use in Bile Duct Regeneration.

Three-dimensional (3D) printing, combined with medical imaging technologies, such as computed tomography and magnetic resonance imaging (MRI), has shown a great potential in patient-specific tissue regeneration. Here, we successfully fabricated an ultrathin tubular free-form structure with a wall thickness of several tens of micrometers that is capable of providing sufficient mechanical flexibility. Such a thin geometry cannot easily be achieved by 3D printing alone; therefore, it was realized through a serial combination of processes, including the 3D printing of a sacrificial template, the dip coating of the biomaterial, and the removal of the inner template.

Creation of a Hybrid Scaffold with Dual Configuration of Aligned and Random Electrospun Fibers.

A novel hybrid construct was developed by combining aligned fibers (AFs) and random fibers (RFs) to form a scaffolding system. Homogeneous fiber-based structures were fabricated by electrospinning, which produced both random and aligned fiber mats depending on the collection method. The upper part of the scaffold contained an AF layer, which possessed a well-organized configuration that provided uniaxial topographic guidance.