In-situ Printing : regenerative medicine for complex wounds, and space-based healthcare
A team led by Prof. Axel Günther has reported an in situ printing platform for conformal deposition of biomaterial inks on curved anatomical surfaces, with validation under microgravity. Recently published in Biofabrication, the work moves beyond conventional descriptions of “3D bioprinting” by focusing on point-of-care delivery directly onto anatomically relevant surfaces, rather than fabrication of free-standing constructs away from the patient. At the core of the platform is a clinically relevant biphasic jammed ink made from gelatin microgels suspended in fibrinogen, designed to preserve shape fidelity immediately after extrusion while supporting cell viability and downstream adhesion.
Overview of in situ printing performance on curved surfaces and under variable gravity. (A) Schematic of patient facial wounds with varying convex curvatures, characterized by principal curvature radii R₁ (in plane parallel to printing) and R₂ (perpendicular plane to printing). The approach targets challenging anatomical regions such as the forehead, chin, and nose, where gravity-induced drainage often occurs on inclined surfaces. (B) Area coverage rates for different ink classes (synthetic, polysaccharide, photocurable, protein-based, and biphasic) relative to substrate curvature. The biphasic jammed ink developed in this work achieves high coverage even on strongly convex surfaces. (C) Illustration of gravity regimes, ranging from microgravity (0 g, e.g., International Space Station) to partial gravity (0.17 g, Moon; 0.38 g, Mars) and Earth gravity (1 g). (D) Comparison of area coverage rates across gravitational accelerations for different ink classes, showing the superior performance of the biphasic (jammed) system
To address the challenge of printing across complex human topographies, the researchers developed BRUSH (Bioprinting Rapidly Using a Shape-Adaptable Head), a soft-robotically actuated multinozzle printhead with an embedded curvature sensor. In closed-loop operation, the printhead matched target curvature within 1.5 seconds and tracked changing physiological curvatures, enabling uniform deposition across flat, inclined, and curved surfaces. The group also identified a ladder-rung channel architecture that improved uniformity and reduced clogging during high-throughput extrusion.
The system was then used to deposit cell-laden biphasic jammed bioinks on physiologically relevant facial geometries, including chin and nose phantoms. Printed constructs remained adherent after two weeks in culture, while maintaining fibroblast viability above 85% and continued proliferation, supporting the platform’s promise for regenerative medicine applications on difficult, highly curved wound sites.
The study also extended this concept into space-based healthcare. During parabolic flight, the team used a rigid multinozzle printhead integrated into a handheld bioprinter to demonstrate the first reported deposition of a biphasic jammed biomaterial ink under microgravity conditions. Printed sheets maintained approximately 1 mm thickness, and fibrin network formation was not significantly different from ground-based controls. The platform also achieved substantially higher area coverage and faster translation than the group’s earlier handheld systems.
Together, the work advances in situ printing as a practical biofabrication strategy for regenerative medicine in settings where anatomy, gravity, and logistics all matter, from the operating room to austere trauma care and future long-duration space missions. The paper positions this as a translational step forward, while noting that in vivo preclinical validation remains an important next milestone.