Thermokinetics and rheology of agarose gel applied to bioprinting technology

Abstract

The paper presents new results on the study of thermokinetics of gel system based on agarose in the process of transition from solution to gel and opposite. This issue is extremely relevant, since the stability and predictability of thermophysical and rheological properties in such transformations, especially in the presence of components of the nutrient medium and immobilized microorganisms, come to the fore in terms of design and selection of modes of operation of the printing device promising 3-D bioprinters, as well as the system of preparation and storage of the presence of the hysteresis effect, both from the point of view of the kinetics of gel formation and from the point of view of the dependence of rheological properties on temperature, at different concentrations of modifying components, is shown. The obtained results allow to draw a conclusion about the possibility of using the scheme with preliminary preparation of the initial biogel for the implementation of bioprinting technology based on agarose, and to recommend the obtained values for modeling the operating modes of devices of this type.

A Guide to Polysaccharide-Based Hydrogel Bioinks for 3D Bioprinting Applications

“…The gelling mechanism of agarose occurs upon cooling and lies in the establishment of intermolecular hydrogen bonds, which lead to the formation of side-by-side chain aggregates originating the gel network [ 92 ]. Once agarose gels are formed, at around 32–34 °C, they are stable and do not re-liquefy until heated to 65 °C [ 93 ].…”

“…Alternative applications of agarose hydrogels in bioprinting processes, rather than bioink components, have also been explored [ 93 ]. At low concentrations (less than 1% ( w / v )), agarose hydrogels can be easily molded and used to cast sub-millimetric geometries [ 93 ].…”

“…Alternative applications of agarose hydrogels in bioprinting processes, rather than bioink components, have also been explored [ 93 ]. At low concentrations (less than 1% ( w / v )), agarose hydrogels can be easily molded and used to cast sub-millimetric geometries [ 93 ]. Taking advantage of this feature, Aydin et al [ 78 ] developed a bioink composed of agarose and alginate, produced by a microwave-assisted method, where agarose served as a self-eroding sacrificial part to cast tubular structures within the cell-laden alginate, generating living printed constructs with a vascularized network.…”

Instability of the printing jet during the three-dimensional-printing process

“…The three-dimensional-printing technology is now playing an important role in materials science, constructional engineering, and food engineering. [1][2][3][4][5] It can print micro/nano devices, e.g. micro-electromechanical systems 6 and Fangzhu-like devices for collecting water from air.…”

“…In the three-dimensional-printing process [1][2][3][4][5] (see Figure 2), an instability often occurs for the slender axially moving jet, and the instability always leads to morphology change of the printed object. The instability also occurs in some spinning process, see, for example, the following works.…”