Inverse Thermogelation of Aqueous Triblock Copolymer Solutions into Macroporous Shear-Thinning 3D Printable Inks

Area of Science:

• Polymer Science
• Materials Science
• Biomaterials

Background:

• Amphiphilic block copolymers are crucial for applications like drug delivery and tissue engineering due to their ability to form physical gels in water.
• Investigating novel copolymer structures is key to advancing biomaterial capabilities.

Purpose of the Study:

• To explore ABA-type triblock copolymers with poly(2-oxazoline) shells and aromatic poly(2-oxazine) cores for aqueous gelation.
• To characterize the thermogelation behavior, viscoelastic properties, and 3D printing potential of these novel copolymers.

Main Methods:

• Synthesis and characterization of ABA-type triblock copolymers.
• Investigation of aqueous solutions' behavior at varying concentrations and temperatures.
• Rheological measurements to determine viscoelastic properties.
• 3D printing of scaffolds and microstructural analysis using cryo-SEM.

Main Results:

• Poly(2-methyl-2-oxazoline)-block-poly(2-phenyl-2-oxazine)-block-poly(2-methyl-2-oxazoline) (PMeOx-b-PPheOzi-b-PMeOx) exhibits inverse thermogelation, forming a wormlike network below a critical temperature.
• The resulting hydrogel shows tunable viscoelasticity (up to 110 kPa storage modulus), shear-thinning, and rapid self-healing properties.
• Successfully 3D printed shape-persistent, 24-layered scaffolds with a stable macroporous structure.
• Demonstrated absence of cytotoxicity even at high concentrations.

Conclusions:

• PMeOx-b-PPheOzi-b-PMeOx is a promising new biomaterial for biofabrication and other applications due to its inverse thermogelation and tunable properties.
• The material's shear-thinning, self-healing, and printability make it suitable for creating complex 3D structures.
• Its non-cytotoxic nature broadens its potential use in various biomedical fields.