Dragging 3D printing technique controls pore sizes of tissue engineered blood vessels to induce spontaneous cellular assembly

To date,several off-the-shelf products such as artificial blood vessel grafts have been reported and clinically tested for small diameter vessel(SDV)replacement.However,conventional artificial blood vessel grafts lack endothelium and,thus,are not ideal for SDV transplantation as they can cause thrombosis.In addition,a suc-cessful artificial blood vessel graft for SDV must have sufficient mechanical properties to withstand various external stresses.Here,we developed a spontaneous cellular assembly SDV(S-SDV)that develops without additional intervention.By improving the dragging 3D printing technique,SDV constructs with free-form,multilayers and controllable pore size can be fabricated at once.Then,The S-SDV filled in the natural poly-mer bioink containing human umbilical vein endothelial cells(HUVECs)and human aorta smooth muscle cells(HAoSMCs).The endothelium can be induced by migration and self-assembly of endothelial cells through pores of the SDV construct.The antiplatelet adhesion of the formed endothelium on the luminal surface was also confirmed.In addition,this S-SDV had sufficient mechanical properties(burst pressure,suture retention,leakage test)for transplantation.We believe that the S-SDV could address the challenges of conventional SDVs:notably,endothelial formation and mechanical properties.In particular,the S-SDV can be designed simply as a free-form structure with a desired pore size.Since endothelial formation through the pore is easy even in free-form con-structs,it is expected to be useful for endothelial formation in vascular structures with branch or curve shapes,and in other tubular tissues such as the esophagus.

Application of 3D bioprinting in the prevention and the therapy for human diseases

Rapid development of vaccines and therapeutics is necessary to tackle the emergence of new pathogens and infectious diseases.To speed up the drug discovery process,the conventional development pipeline can be retooled by introducing advanced in vitro models as alternatives to conventional infectious disease models and by employing advanced technology for the production of medicine and cell/drug delivery systems.In this regard,layer-by-layer construction with a 3D bioprinting system or other technologies provides a beneficial method for developing highly biomimetic and reliable in vitro models for infectious disease research.In addition,the high flexibility and versatility of 3D bioprinting offer advantages in the effective production of vaccines,therapeutics,and relevant delivery systems.Herein,we discuss the potential of 3D bioprinting technologies for the control of infectious diseases.We also suggest that 3D bioprinting in infectious disease research and drug development could be a significant platform technology for the rapid and automated production of tissue/organ models and medicines in the near future.

Real-time multiaxial strain mapping using computer vision integrated optical sensors

Soft strain sensors pose great potential for emerging human–machine interfaces.However,their real-world applications have been limited due to challenges such as low reproducibility,susceptibility to environmental noise,and short lifetimes,which are attributed to nanotechnologies,including microfabrication techniques.In this study,we present a computer vision-based optical strain(CVOS)sensor system that integrates computer vision with streamlined microfabrication techniques to overcome these challenges and facilitate real-time multiaxial strain mapping.The proposed CVOS sensor consists of an easily fabricated soft silicone substrate with micro-markers and a tiny camera for highly sensitive marker detection.Real-time multiaxial strain mapping allows for measuring and distinguishing complex multi-directional strain patterns,providing the proposed CVOS sensor with higher scalability.Our results indicate that the proposed CVOS sensor is a promising approach for the development of highly sensitive and versatile human–machine interfaces that can operate long-term under real-world conditions.