In vitro pre-vascularization strategies for tissue engineered constructs–Bioprinting and others

Abstract

In vitro pre-vascularization strategies for tissue engineered constructs-Bioprinting and others. © 2017 Andy Wen Loong Liew. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons. org/licenses/by-nc/4.0/), permitting all non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 3 RESEARCH ARTICLEIn vitro pre-vascularization strategies for tissue engineered constructs-Bioprinting and others Andy Wen Loong Liew and Yilei Zhang * Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore Abstract: Tissue-engineered products commercially available today have been limited to thin avascular tissue such as skin and cartilage. The fabrication of thicker, more complex tissue still eludes scientists today. One reason for this is the lack of effective techniques to incorporate functional vascular networks within thick tissue constructs. Vascular networks provide cells throughout the tissue with adequate oxygen and nutrients; cells located within thick un-vascularized tissue implants eventually die due to oxygen and nutrient deficiency. Vascularization has been identified as one of the key components in the field of tissue engineering. In order to fabricate biomimetic tissue which accurately recapitulates our native tissue environment, in vitro pre-vascularization strategies need to be developed. In this review, we describe various in vitro vascularization techniques developed recently which employ different technologies such as bioprinting, microfluidics, micropatterning, wire molding, and cell sheet engineering. We describe the fabrication process and unique characteristics of each technique, as well as provide our perspective on the future of the field.

In vivo bone regeneration assessment of offset and gradient melt electrowritten (MEW) PCL scaffolds

“…Statistically significant differences between Bmp-2 intensity scores for the treatment groups when compared to each other were determined by ANOVA (Significant: * p < 0.0001,^p = 0.009, ■ p = 0.005, ♦ p = 0.002, ▼p = 0.005, • p < 0.0001) is MEW [10]. Although open-cell pores might be more applicable to promote osteogenesis due to better access of oxygen and new bone development into the porosities as well as better vasularization through the channels created by pores connections [28], the type of pores obtaining by MEW technique are the closed-cells pores without interconnectivity with each other and enclosed by the pore walls [29]. A 5 mm calvarial defect was used in our study to evaluate new bone formation.…”

“…One of the most promising methods to control scaffold pore size and the level of porosity is MEW [ 10 ]. Although open-cell pores might be more applicable to promote osteogenesis due to better access of oxygen and new bone development into the porosities as well as better vasularization through the channels created by pores connections [ 28 ], the type of pores obtaining by MEW technique are the closed-cells pores without interconnectivity with each other and enclosed by the pore walls [ 29 ].…”

Vascularization strategies in tissue engineering approaches for soft tissue repair

“…The diffusion of oxygen and nutrients, which has been reported to be approximately 100-200 μm, from the pre-existing vasculature will likely not be enough to reach and keep the cells viable in the core of these equivalents. Thus, vascularization might be compromised leading to insufficient oxygen and nutrient supply, and potentially to necrosis and failure of the implant (Liew, Zhang, & Yilei, 2017;Tomasina et al, 2019;Yang et al, 2020).…”

Cell powered biobots and more perspectives for IJB

“…Liew and Zhang review in vitro pre-vascularization strategies for tissue engineered constructs [1] . Whitford and Hoying review recent development in bioinks that support vascularization [2] .…”

“…In this issue, there are 3 reviews, 4 original research articles and 1 perspective. Liew and Zhang review in vitro pre-vascularization strategies for tissue engineered constructs[ 1 ]. Whitford and Hoying review recent development in bioinks that support vascularization[ 2 ].…”