Vertical Extrusion Cryo(bio)printing for Anisotropic Tissue Manufacturing

Standard 3D extrusion bioprinting is limited to horizontal layer stacking due to weak hydrogel bioink properties. This approach restricts vertical construction and structural complexity. Prior studies have shown that hydrogel bioinks often lack sufficient mechanical strength for vertical extrusion. No prior work had resolved the issue of printing vertically with living cells in weak gels. This gap motivated the development of a temperature-controlled freezing method. The freezing plate allows vertical extrusion without layer collapse. This technique introduces anisotropic microchannels aligned vertically. It offers a new way to engineer tissues with directional properties.

The aim of this work is to develop a bioprinting method that enables vertical extrusion with living cells. The challenge is to overcome the mechanical limitations of hydrogel bioinks. The freezing plate is used to solidify the extruded material instantly. This allows vertical printing without support structures. The study focuses on creating anisotropic tissue constructs. Skeletal myoblasts are used to test cell behavior in printed structures. The goal is to improve tissue engineering for muscle and vascular units. This approach may enhance tissue functionality and structural complexity.

A freezing plate with precise temperature control is used to solidify the extruded bioink. The cryoprotective bioink is extruded vertically onto the freezing surface. The freezing process prevents sagging and allows vertical filament formation. The printed constructs contain aligned microchannels in the vertical direction. Skeletal myoblasts are embedded in the hydrogel during printing. Cell viability and alignment are assessed using microscopy techniques. The method is extended to multimaterial printing for tissue interfaces. The constructs are tested for mechanical performance and structural integrity.

Vertical extrusion is achieved using a freezing plate with controlled temperature. The printed constructs have anisotropic microchannels aligned vertically. The microchannels are interconnected and have gradient sizes. Skeletal myoblasts show improved viability in cryo-bioprinted constructs. Cell spreading and alignment are enhanced compared to standard gels. The constructs exhibit better mechanical performance than conventional prints. The method supports multimaterial printing for tissue interfaces. This technique may be useful for muscle-tendon and muscle-vascular units.

The vertical cryo-bioprinting method improves tissue engineering by enabling vertical extrusion. The freezing plate allows direct printing of anisotropic constructs with living cells. The printed structures have aligned microchannels and enhanced mechanical properties. Skeletal myoblasts demonstrate better viability and alignment in the new constructs. The multimaterial format supports interface tissue engineering applications. This approach may benefit muscle-tendon and muscle-vascular unit fabrication. The method suggests potential in regenerative medicine and drug discovery. The authors propose that this technique enhances robustness and versatility in tissue engineering.