Fabrication of Microspheres from High-Viscosity Bioink Using a Novel Microfluidic-Based 3D Bioprinting Nozzle

Abstract

Three-dimensional (3D) bioprinting is a novel technology utilizing biocompatible materials, cells, drugs, etc. as basic microcomponents to form 3D artificial structures and is believed as a promising method for regenerative medicine. Droplet-based bioprinting can precisely generate microspheres and manipulate them into organized structures with high fidelity. Biocompatible hydrogels are usually used as bioinks in 3D bioprinting, however, the viscosity of the bioink could be increased due to the additives such as cells, drugs, nutrient factors and other functional polymers in some particular applications, making it difficult to form monodispersed microspheres from high-viscosity bioink at the orifice of the nozzle. In this work, we reported a novel microfluidic-based printing nozzle to prepare monodispersed microspheres from high-viscosity bioink using the phase-inversion method. Different flowing conditions can be achieved by changing the flow rates of the fluids to form monodispersed solid and hollow microspheres using the same nozzle. The diameter of the microspheres can be tuned by changing the flow rate ratio and the size distribution of the microspheres is narrow. The prepared calcium alginate microspheres could also act as micro-carriers in drug delivery.

Immunomodulatory Microgels Support Proregenerative Macrophage Activation and Attenuate Fibroblast Collagen Synthesis

“…In this case, the work required for generating uniform droplets may be provided by altering the flow rate ratio of the liquid phase to the oil phase. [ 66 ]…”

“…In this case, the work required for generating uniform droplets may be provided by altering the flow rate ratio of the liquid phase to the oil phase. [66] As shown by images with higher magnification, the PM was nonporous and homogenous, with only a few holes on the surface. The addition of HAMA produced several small, nonuniformly distributed pores.…”

Physical and Mechanical Characterization of Fibrin-Based Bioprinted Constructs Containing Drug-Releasing Microspheres for Neural Tissue Engineering Applications

“…Low viscosity bioinks increase cell viability but often decrease the printed construct's fidelity [10], while bioinks with high viscosity have high structural fidelity but can result in more cell damage and death [45]. The bioink's viscosity can be modified by incorporating biological factors, drug-delivery carriers, nanomaterials, and combinations of biopolymers to improve their mechanical properties [18,46].…”

Prevascularized Micro-/Nano-Sized Spheroid/Bead Aggregates for Vascular Tissue Engineering

“…Droplet-based bioprinting (DBB) use a bioink solution to generate biomaterials droplets and cells in high precision. Droplet-based techniques can be further classified into inkjet bioprinting, microvalve bioprinting and acoustic-dropletejection bioprinting [126][127][128][129]. Droplet-based bioprinting is appropriate for printing microvasculature for high-resolution patterning in the diameter range of 50 − 300 μm (Fig.…”