Experimental validation of coronary stenosis severity and development of ischemic myocardium.

Introduction And Objectives: The current study aimed to evaluate the causal association between hemodynamically significant stenosis and the occurrence of ischemic myocardium using an experimental animal model of coronary artery stenosis.

Methods: In Yorkshire swine (n=10), coronary stenosis in the left anterior descending artery was induced using a customized vascular occluder to create varying degrees of occlusion severity (40%-99%). Serial changes in coronary pressure and flow velocity were measured in the left anterior descending artery before and after the implantation of the vascular occluder.

3D bioprinting strategy for engineering vascularized tissue models.

Leveraging three-dimensional (3D) bioprinting in the fields of tissue engineering and regenerative medicine has rapidly accelerated progress toward the development of living tissue constructs and biomedical devices. Ongoing vigorous research has pursued the development of 3D tissue models to replicate the key aspects of human physiology by incorporating relevant cell populations and adequate environmental cues. Given their advantages of being able to intimately mimic the heterogeneity and complexity of their native counterparts, 3D models hold promise as alternatives to conventional cell cultures or animal models for translational application to model human physiology/pathology and drug screening.

Nanoscale Characterization of Photocurrent and Photovoltage in Polycrystalline Solar Cells.

We investigate the role of grain structures in nanoscale carrier dynamics of polycrystalline solar cells. By using Kelvin probe force microscopy (KPFM) and near-field scanning photocurrent microscopy (NSPM) techniques, we characterize nanoscopic photovoltage and photocurrent patterns of inorganic CdTe and organic-inorganic hybrid perovskite solar cells. For CdTe solar cells, we analyze the nanoscale electric power patterns that are created by correlating nanoscale photovoltage and photocurrent maps on the same location.

Feasibility and safety of a novel 3D-printed biodegradable biliary stent in an in vivo porcine model: a preliminary study.

To assess the feasibility and safety of a novel 3D-printed biodegradable biliary stent using polycaprolactone (PCL) in an in vivo porcine model. In this animal study using domestic pigs, biodegradable radiopaque biliary stents made of polycaprolactone (PCL) and barium sulfate were produced using 3D printing and surgically inserted into the common bile duct (CBD) of pigs (stent group, n = 12). Another five pigs were allocated to the control group that only underwent resection and anastomosis of the CBD without stent insertion.

3D Bioprinting of In Vitro Models Using Hydrogel-Based Bioinks.

Coronavirus disease 2019 (COVID-19), which has recently emerged as a global pandemic, has caused a serious economic crisis due to the social disconnection and physical distancing in human society. To rapidly respond to the emergence of new diseases, a reliable in vitro model needs to be established expeditiously for the identification of appropriate therapeutic agents. Such models can be of great help in validating the pathological behavior of pathogens and therapeutic agents.

3D cell-printing of tendon-bone interface using tissue-derived extracellular matrix bioinks for chronic rotator cuff repair.

The tendon-bone interface (TBI) in rotator cuffs exhibits a structural and compositional gradient integrated through the fibrocartilaginous transition. Owing to restricted healing capacity, functional regeneration of the TBI is considered a great clinical challenge. Here, we establish a novel therapeutic platform based on 3D cell-printing and tissue-specific bioinks to achieve spatially-graded physiology for functional TBI regeneration.

Flexible Adipose-Vascular Tissue Assembly Using Combinational 3D Printing for Volume-Stable Soft Tissue Reconstruction.

A new concept, assembling cell-laden tissue modules, is for the first time proposed for soft tissue engineering. Adipose-vascular tissue modules composed of a synthetic polymer-based substructure and customized bioinks using planar 3D cell printing are engineered. Such tissue modules are systematically assembled into a synthetic polymer-based module holder fabricated with rotational 3D printing, resulting in the development of a flexible and volumetric tissue assembly.

Therapeutic effect of decellularized extracellular matrix-based hydrogel for radiation esophagitis by 3D printed esophageal stent.

Radiation esophagitis, the most common acute adverse effect of radiation therapy, leads to unwanted consequences including discomfort, pain, an even death. However, no direct cure exists for patients suffering from this condition, with the harmful effect of ingestion and acid reflux on the damaged esophageal mucosa remaining an unresolved problem. Through the delivery of the hydrogel with stent platform, we aimed to evaluate the regenerative capacity of a tissue-specific decellularized extracellular matrix (dECM) hydrogel on damaged tissues.

Multi-layered Free-form 3D Cell-printed Tubular Construct with Decellularized Inner and Outer Esophageal Tissue-derived Bioinks.

The incidences of various esophageal diseases (e.g., congenital esophageal stenosis, tracheoesophageal fistula, esophageal atresia, esophageal cancer) are increasing, but esophageal tissue is difficult to be recovered because of its weak regenerative capability.

Visibility of Bioresorbable Vascular Scaffold in Intravascular Ultrasound Imaging.

Bioresorbable vascular scaffold (BVS) has recently been spotlighted for its unique characteristics of absorbing into blood vessels and eventually disappearing. Although intravascular ultrasound (IVUS) is the most common guiding tool for stent deployment, the echogenicity of BVS struts has changed as the center of stent lumen and scanning rotation is not concentric, which may cause a critical erroneous measurement in practice. This study investigated the physical conditions for dimming the stent brightness in IVUS images using a finite-difference method (FDM) to numerically solve acoustic wave propagation through nonhomogeneous medium.

Development of a radiopaque, long-term drug eluting bioresorbable stent for the femoral-iliac artery.

Tubular tissues exist in various forms purported for blood supply, waste secretion, to aid proper function and maintenance of the human body. Under pathological conditions, however, these tissues may undergo stenosis. A major surgical treatment for stenosis is to implant a medical device called a stent which aims to expand the narrowed tissue and maintain its patency.

Marine-derived natural polymer-based bioprinting ink for biocompatible, durable, and controllable 3D constructs.

3D bioprinting (3DBP) is a rapid solid-form fabrication method with a high degree of automation and reproducibility for constructing structural bioscaffolds. However, the development of the 3DBP field has been slowed due to difficulty in acquiring suitable ink materials especially with natural polymers that satisfy all requirements, such as printability, mechanical integrity, and biocompatibility. In this study, a new 3DBP ink of bioengineered sea anemone-derived silk-like protein (aneroin) was used based on its durable mechanical properties and biodegradability in previous studies.

Correction: Indirect fabrication of versatile 3D microfluidic device by a rotating plate combined 3D printing system.

[This corrects the article DOI: 10.1039/C8RA08465C.].

Indirect fabrication of versatile 3D microfluidic device by a rotating plate combined 3D printing system.

In the past decade, 3D-printing technology has been applied in the field of microfluidics to fabricate microfluidic devices for wide-ranging areas of study including chemistry, biology, medicine, and others. However, these methods face several limitations such as insufficient resolution and long fabrication time. In this study, versatile microfluidic devices with different functions were indirectly fabricated by a rapid sacrificial template printing process using a photocurable fluoropolymer with chemical durability.

Development of a functional airway-on-a-chip by 3D cell printing.

We used 3D cell printing to emulate an airway coupled with a naturally-derived blood vessel network in vitro. Decellularized extracellular matrix bioink derived from porcine tracheal mucosa (tmdECM) was used to encapsulate and print endothelial cells and fibroblasts within a designated polycarprolactone (PCL) frame. Providing a niche that emulates conditions in vivo, tmdECM gradually drives endothelial re-orientation, which leads to the formation of a lumen and blood vessel network.

Nasal Reconstruction Using a Customized Three-Dimensional-Printed Stent for Congenital Arhinia: Three-Year Follow-up.

A male Mongolian child with a complete congenital absence of both nose and nasal passage had a poor survival prognosis due to respiratory distress. To enable his survival, a new nose capable of conferring respiratory function was constructed. Following reconstructive surgery, an absence of mucoepithelium in the nasal passage can lead to rhinostenosis.

Amnion-Analogous Medical Device for Fetal Membrane Healing: A Preclinical Long-Term Study.

Although recent invasive fetal surgeries have improved fetal outcomes, fetal membrane rupture remains a major complication, leading to premature delivery, thus undermining the complete benefits of such procedures. A biocompatible amnion-analogous medical device (AMED) consisting of polycaprolactone framework and decellularized amniotic membrane (dAM)-derived hydrogel for restoration of amniotic membrane defect is developed using 3D printing technology. Its efficacy on healing iatrogenic fetal membrane defects in vitro is evaluated, showing that the dAM gel contains migratory and proliferative properties.

Nanoscale imaging of photocurrent enhancement by resonator array photovoltaic coatings.

Nanoscale surface patterning commonly used to increase absorption of solar cells can adversely impact the open-circuit voltage due to increased surface area and recombination. Here, we demonstrate absorptivity and photocurrent enhancement using silicon dioxide (SiO) nanosphere arrays on a gallium arsenide (GaAs) solar cell that do not require direct surface patterning. Due to the combined effects of thin-film interference and whispering gallery-like resonances within nanosphere arrays, there is more than 20% enhancement in both absorptivity and photocurrent.

Paper in Electronic and Optoelectronic Devices.

Paper, one of the oldest materials for storage and exchange of human's information, has been reinvented as a building component of electronic and optoelectronic devices over the past decades with successful demonstration of paper-based or paper-using devices. These recent achievements can meet the demand for lightweight, cost-effective, and/or flexible electronic and optoelectronic devices with advanced functionality and reduced manufacturing costs. This article provides a review of electronic and optoelectronic devices relying on or making use of the unique properties achievable with paper-based materials.

Improving dielectric nanoresonator array coatings for solar cells.

Antireflection coatings based on dielectric nanosphere arrays are discussed in application to photovoltaic materials including silicon and gallium arsenide. We perform macro- and nanoscale characterization and finite-difference time-domain calculations demonstrating the enhanced optoelectronic properties. A significant absorptivity enhancement is achieved due to the collective resonant coupling of excited whispering gallery-like modes and thin-film interference effects.

Development of Liver Decellularized Extracellular Matrix Bioink for Three-Dimensional Cell Printing-Based Liver Tissue Engineering.

The liver is an important organ and plays major roles in the human body. Because of the lack of liver donors after liver failure and drug-induced liver injury, much research has focused on developing liver alternatives and liver in vitro models for transplantation and drug screening. Although numerous studies have been conducted, these systems cannot faithfully mimic the complexity of the liver.

Robust tissue growth and angiogenesis in large-sized scaffold by reducing HO-mediated oxidative stress.

The implantation of cell-seeded large-sized scaffold often results in insufficient tissue regeneration, which is still a challenge for successful grafting. Excess hydrogen peroxide (HO) released by cells propagates oxidative stress, which is the primary cause of tissue injury leading to failure in tissue regeneration. Hence, preventing tissue from oxidative damage becomes imperative.

Smart Microbubble Eluting Theranostic Stent for Noninvasive Ultrasound Imaging and Prevention of Restenosis.

A pH-responsive microbubble-eluting theranostic stent is developed for real-time ultrasound imaging of stent implanted blood vessels and dissolution of fat-rich plaques to prevent the blocking of blood vessels in rats. This smart theranostic stent can be effectively applied to facilitate noninvasive monitoring and prevent restenosis after stent implantation.

Demonstration of Resonance Coupling in Scalable Dielectric Microresonator Coatings for Photovoltaics.

To increase the power conversion efficiency of solar cells, improved antireflection coatings are needed to couple light into the cell with minimal parasitic loss. Here, we present measurements and simulations of an antireflection coating based on silicon dioxide (SiO2) nanospheres that improve solar cell absorption by coupling light from free space into the absorbing layer through excitation of modes within the nanospheres. The deposited monolayer of nanospheres leads to a significant increase in light absorption within an underlying semiconductor on the order of 15-20%.