Shear-Thinning and Thermo-Reversible Nanoengineered Inks for 3D Bioprinting

TLDR

3D bioprinting promises rapid fabrication of complex tissue structures, yet progress is limited by the lack of printable, shape‑faithful, mechanically resilient bioinks; κCA, a biocompatible polysaccharide from red algae, offers thermo‑reversible and ionic gelation properties. The study introduces a nanoengineered bioink combining κCA with two‑dimensional nanosilicates. Shear‑thinning of κCA is tuned with nanosilicates, and adjusting κCA‑nanosilicate ratios controls thermo‑reversible gelation to achieve high printability and shape retention. The κCA‑nSi bioink can print physiologically relevant‑scale tissue constructs without secondary supports and is envisioned to enable large‑scale, cell‑laden constructs with high fidelity and tunable stiffness for regenerative medicine.

Abstract

Three-dimensional (3D) printing is an emerging approach for rapid fabrication of complex tissue structures using cell-loaded bioinks. However, 3D bioprinting has hit a bottleneck in progress because of the lack of suitable bioinks that are printable, have high shape fidelity, and are mechanically resilient. In this study, we introduce a new family of nanoengineered bioinks consisting of kappa-carrageenan (κCA) and two-dimensional (2D) nanosilicates (nSi). κCA is a biocompatible, linear, sulfated polysaccharide derived from red algae and can undergo thermo-reversible and ionic gelation. The shear-thinning characteristics of κCA were tailored by nanosilicates to develop a printable bioink. By tuning κCA-nanosilicate ratios, the thermo-reversible gelation of the bioink can be controlled to obtain high printability and shape retention characteristics. The unique aspect of the nanoengineered κCA-nSi bioink is its ability to print physiologically-relevant-scale tissue constructs without requiring secondary supports. We envision that nanoengineered κCA-nanosilicate bioinks can be used to 3D print complex, large-scale, cell-laden tissue constructs with high structural fidelity and tunable mechanical stiffness for regenerative medicine.