Thermo-responsive properties of methylcellulose hydrogels for cell sheet engineering

Methylcellulose – a versatile printing material that enables biofabrication of tissue equivalents with high shape fidelity

“…The gelation temperature, as well as the gel strength, are dependent on the DS, concentration and molecular weight (M w ) of mc as well as on electrolyte concentrations. 17,[20][21][22][23][24] In brief, an increasing DS and mc concentration will decrease the gelation temperature, 25 whereas increasing M w will especially enhance the gel strength. Increased ionic strength, caused e.g.…”

“…That strategy was applied for enhanced cell sheet engineering utilizing the strong dependence of the gelation process of mc on electrolyte concentrations. 21,25 MC solutions of a concentration of 8 wt% were prepared in salt-containing solutions and printed in ring-like structures with high shape fidelity (outer diameter 10 mm, inner diameter 6 mm, the obtained printed structures revealed the same dimensions). 39,40 Afterwards, fibroblasts and endothelial cells were seeded on top; non-printed bulk samples acted as controls.…”

Biopolymer-based strategies in the design of smart medical devices and artificial organs

“…Methylcellulose (MC) is a water-soluble polymer derived from cellulose, obtained by the partial substitution of hydrophilic hydroxyl groups with hydrophobic methoxy groups. 116 , 117 , 124 MC is an LCST hydrogel, and its main advantage is its ability to form a gel at physiological temperature, whereas it is in a sol state at a lower temperature. MC sol–gel transition has been investigated in depth in order to develop MC-based hydrogels for tissue engineering and regenerative medicine applications (see section “CSE”).…”

“…For this specific application, thermo-responsive polymers are designed to be hydrophobic at 37°C ( Figure 4(a) ), the ideal condition for cell seeding and adhesion, and hydrophilic at room temperature ( Figure 4(c) ), so that the cells can easily be detached from the substrate by lowering the temperature. 29 , 47 , 116 – 121 , 149 , 150 …”

“…Recently, some efforts have been made to systematically investigate the thermo-responsive behavior of MC-based hydrogels, in order to evaluate their potential in the field of CSE. 116 – 118 An increase in polymer concentration was found to promote polymer–polymer interactions at lower temperatures, causing a decrease in the sol–gel transition temperature (LCST). The dissociation of salts in MC aqueous solutions produces ions, which act on the interactions between polymer macromolecules and water molecules, shifting the LCST of MC-based hydrogels either to lower (salting-out ions) or to higher (salting-in ions) temperatures than a purely aqueous MC solution.…”