4D Printing for Vascular Tissue Engineering: Progress and Challenges

Abstract

The hierarchical network of blood vessels comprises the larger vessels (veins and arteries), the smaller ones (venules and arterioles), and the thinnest capillaries. The proper functioning of most tissues in the body relies on vascularization, which is meant for the diffusion of gases, nutrients, and harmful waste. However, it is known that cell survival is compromised as the diffusion of oxygen is limited beyond 100–200 µm and damage can occur at any level of the complex system of the vascular network, as is the case in cardiovascular, musculoskeletal, and neurovascular diseases that recur and progress with age. These may prove fatal, hence the need for vascular tissue engineering (VTE) arises. VTE mainly focuses on the fabrication of vascular constructs using natural, synthetic material, or a combination of both using various techniques. The construct is expected to integrate and anastomose with the host vasculature. 4D bioprinting is an emerging field that allows the fabrication of hollow tubes employing different materials that respond to different stimuli. This review is a comprehensive summary of the major techniques employed in VTE and the recent technique of 4D bioprinting foreseen to revolutionize the field.

Human–Material Interaction Enabled by Fused Filament Fabrication 4D Printing

“…Presently, the predominant focus of 4DP research and review revolves around biomedical and medical applications, [ 19–21 ] soft robotics, [ 22,23 ] electronic devices, [ 24 ] wearable devices, [ 25 ] construction, [ 26 ] dentistry, [ 27 ] and agriculture. [ 28 ] While there is a significant body of literature on 4DP, a dearth of research and review focused specifically on fused filament fabrication (FFF) 4DP of human–material interaction (HMI) for end‐user products remains.…”

Vat polymerization 3D printing of composite acrylate photopolymer-based coated glass beads

“…Safety gear, dental implants, and drug delivery systems are some of the additional medical applications that have been examined. The results point to the need for enhanced design methodologies to navigate the complicated choice space made possible by 3D printing [23][24][25]. In addition, for the improvement and development of vat photopolymerization-based techniques, the development of photopolymers and related materials such as photoinitiators, UV curing monomers and oligomers, and multi-functional cross-linkers is needed, and interesting works have been done in this regard recently.…”

Coaxial 4D Printing of Vein‐Inspired Thermoresponsive Channel Hydrogel Actuators

“…[32] One of the most outstanding applications of 4D bioprinting is the creation of mature functional perfusable tissue models capable of changing their functionality in time. [37][38][39] It is, therefore, simply a matter of time until 4D bioprinting is integrated with a coaxial nozzle for 4D vascularized tissue fabrication. A great foundation for this approach has been proposed only recently by Wang et al, who presented a versatile microfluidic 3D printing strategy to fabricate black phosphorus (BP)-incorporated PNIPAAm-based scaffolds with photothermal responsive channels for improving vascularization and bone regeneration.…”