Development of a multifunctional, acoustofluidic 3D bioprinter with single-cell resolution - Project Summary Three-dimensional (3D) bioprinting is a rapidly emerging technology that has the potential to quickly print customized, functional, biological tissues. In recent years, much progress has been made in modifying traditional printing systems for 3D bioprinting. However, their printed tissues often lack the resolution and complexity necessary to achieve the essential functions, physiological conditions, and anisotropic properties found in native tissues. Therefore, there is a critical need to develop next-generation 3D bioprinting instruments that address the following three key technologic limitations: (1) the inability to control internal cell positions in printed matrix material voxels and achieve the desired cell-cell spacing (i.e., cell proximity resolution < 10 µm) that is critical to ensure proper tissue functions from the cellular level and studying cell-cell interactions in the 3D microenvironments; (2) the inability to print tissues with high local cell densities (>109 cells/mL) as observed in vivo; and (3) the inability to perform scaffold-free printing of large-scale tissues with multiscale biomimetic cellular architectures (e.g., cell pattern and alignment), which are essential to achieve desired anisotropic tissue properties and key functions that depend on multiscale cell arrangements. Over the last ten years, we have developed a series of acoustofluidic (i.e., the fusion of acoustic and microfluidic) technologies, which are excellent candidates to address the bottlenecks above. In particular, we have recently developed acoustofluidic holography, an acoustics-based, biocompatible, and high-resolution cell manipulation technology that allows one to pattern, rotate, and concentrate cell seeded matrix materials before polymerization. Building upon this technology, in this R01 project, we propose to develop and validate an acoustofluidic 3D bioprinting prototype to print functional tissues with high cell proximity resolution (<10 µm) and complex features (such as biomimetic cellular architectures, controlled anisotropic properties, and high cell densities) in a biocompatible, fast, and scalable manner. Our acoustofluidic 3D bioprinter will be validated by printing vascularized tumor spheroids with stroma and anisotropic, innervated, vascularized skeletal muscle tissues. Compared to current 3D bioprinting instruments, our acoustofluidic 3D bioprinter will have multiple advantages including: (1) ability to control internal cell positions of printed matrix voxels and achieve high cell proximity resolution (< 10 µm); (2) ability to print tissues with high local cell densities (>109 cells/mL) and controlled density distributions; (3) ability to print tissues with multiscale cellular architectures and control tissues’ anisotropic properties without using scaffolds; and (4) high biocompatibility (>95% viability). With these advantages, the proposed acoustofluidic 3D bioprinting technology has the potential to significantly exceed current standards and address unmet needs in the 3D bioprinting field. We expect that our acoustofluidic 3D bioprinting technology will be of tremendous value to biomedical research communities working on fundamental in vitro and in vivo studies, cancer research, cell-cell interaction studies, tissue engineering, regenerative medicine, and drug screening.
