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.