Hetero-cellular prototyping by synchronized multi-material bioprinting for rotary cell culture system

Abstract

Bottom-up tissue engineering requires methodological progress of biofabrication to capture key design facets of anatomical arrangements across micro, meso and macro-scales. The diffusive mass transfer properties necessary to elicit stability and functionality require hetero-typic contact, cell-to-cell signaling and uniform nutrient diffusion. Bioprinting techniques successfully build mathematically defined porous architecture to diminish resistance to mass transfer. Current limitations of bioprinted cell assemblies include poor micro-scale formability of cell-laden soft gels and asymmetrical macro-scale diffusion through 3D volumes. The objective of this work is to engineer a synchronized multi-material bioprinter (SMMB) system which improves the resolution and expands the capability of existing bioprinting systems by packaging multiple cell types in heterotypic arrays prior to deposition. This unit cell approach to arranging multiple cell-laden solutions is integrated with a motion system to print heterogeneous filaments as tissue engineered scaffolds and nanoliter droplets. The set of SMMB process parameters control the geometric arrangement of the combined flow's internal features and constituent material's volume fractions. SMMB printed hepatocyte-endothelial laden 200 nl droplets are cultured in a rotary cell culture system (RCCS) to study the effect of microgravity on an in vitro model of the human hepatic lobule. RCCS conditioning for 48 h increased hepatocyte cytoplasm diameter 2 μm, increased metabolic rate, and decreased drug half-life. SMMB hetero-cellular models present a 10-fold increase in metabolic rate, compared to SMMB mono-culture models. Improved bioprinting resolution due to process control of cell-laden matrix packaging as well as nanoliter droplet printing capability identify SMMB as a viable technique to improve in vitro model efficacy.

Airflow‐Assisted 3D Bioprinting of Human Heterogeneous Microspheroidal Organoids with Microfluidic Nozzle

“…Na-alginate solutions can be precisely extruded into several jets with distinct patterns and boundaries by taking advantage of laminar flow. [20][21][22][23][24] Afterward, the extruded droplets are rotated by a small airflow which is accurately set up. Due to the spinning process, the arrangement of different jets inside the droplet becomes tunable which was supposed to be the parallel originally.…”

“…In this research, we present a brand new bioprinting method that provides multicellular asymmetrical microspheroids with a controlled spatial spiral‐based microarchitecture inside the spheroids. By applying a microfluidic nozzle, cell‐laden Na‐alginate solutions can be precisely extruded into several jets with distinct patterns and boundaries by taking advantage of laminar flow . Afterward, the extruded droplets are rotated by a small airflow which is accurately set up.…”

Multimaterial, heterogeneous, and multicellular three-dimensional bioprinting

“…42 Another solution is the use of a single print head and a microfluidic system that mixes the various bioinks, coming from different reservoirs, before extruding a single multimaterial filament, characterized by a stable concentration gradient of the mixed bioinks across the filament section. 43,44 Microfluidic techniques assemble multiple material inlets in a single outlet channel without mixing, due to low inertial forces in microscale cross-sectional channels. Even if the microfluidic approach is limited by the mixing of the same fluid solution with different solutes (or different concentrations of the same solute), sub-needle (filament) resolution can be achieved.…”

Additive Manufacturing of Biomedical Constructs with Biomimetic Structural Organizations

“…A promising solution is tissue/organ printing that employs living cells and biologically-relevant hydrogels as the printing inks to fabricate living 3D constructs in a controlled and layer-by-layer manner. Recent advances in organ printing with multiple bioprinting heads enabled researchers to capture heterocellular organizations of native organs [88,89]. …”