3D Bioprinted Spheroidal Droplets for Engineering the Heterocellular Coupling between Cardiomyocytes and Cardiac Fibroblasts

Abstract

Since conventional human cardiac two-dimensional (2D) cell culture and multilayered three-dimensional (3D) models fail in recapitulating cellular complexity and possess inferior translational capacity, we designed and developed a high-throughput scalable 3D bioprinted cardiac spheroidal droplet-organoid model with cardiomyocytes and cardiac fibroblasts that can be used for drug screening or regenerative engineering applications. This study helped establish the parameters for bioprinting and cross-linking a gelatin-alginate-based bioink into 3D spheroidal droplets. A flattened disk-like structure developed in prior studies from our laboratory was used as a control. The microstructural and mechanical stability of the 3D spheroidal droplets was assessed and was found to be ideal for a cardiac scaffold. Adult human cardiac fibroblasts and AC16 cardiomyocytes were mixed in the bioink and bioprinted. Live-dead assay and flow cytometry analysis revealed robust biocompatibility of the 3D spheroidal droplets that supported the growth and proliferation of the cardiac cells in the long-term cultures. Moreover, the heterocellular gap junctional coupling between the cardiomyocytes and cardiac fibroblasts further validated the 3D cardiac spheroidal droplet model.

Development and Characterization of Furfuryl-Gelatin Electrospun Scaffolds for Cardiac Tissue Engineering

“…Although we did not report the biomarker characterization for gap junction analysis for the AC16 cardiomyocyte cells adhered onto the scaffolds, our previously published works have extensively highlighted the presence of Connexin 43 as a cardiac gap junction expressed by such cells atop f-gelatin-based scaffolds. 36 …”

“…Although we did not report the biomarker characterization for gap junction analysis for the AC16 cardiomyocyte cells adhered onto the scaffolds, our previously published works have extensively highlighted the presence of Connexin 43 as a cardiac gap junction expressed by such cells atop f-gelatin-based scaffolds. 36 The significant difference in elastic modulus was sensed by the cells and led to a higher adhesion of cells on the blended scaffolds with a higher elastic modulus. 44 The exposure of RGD cell-binding sequence in f-gelatin enables the adhesion of the cardiomyocytes to the scaffolds.…”

“…Circular samples of electrospun scaffold mats were made with dimensions of 25 mm diameter and 1 mm thickness for these experiments in accordance with previously published works. 36 An oscillatory shear stress rheometric study was performed using an Anton-Paar MCR 92 rheometer (Anton-Paar, Austria) with a PP25/S measuring system at 1% strain with a frequency range between 0.5 and 50 Hz. 28 , 37 Analysis for frequency and strain was conducted within the viscoelastic range of the samples.…”

“…To examine the rheological properties of the electrospun scaffold, the samples were soaked in 1× PBS for 24 h before testing. Circular samples of electrospun scaffold mats were made with dimensions of 25 mm diameter and 1 mm thickness for these experiments in accordance with previously published works . An oscillatory shear stress rheometric study was performed using an Anton-Paar MCR 92 rheometer (Anton-Paar, Austria) with a PP25/S measuring system at 1% strain with a frequency range between 0.5 and 50 Hz. , Analysis for frequency and strain was conducted within the viscoelastic range of the samples. , The storage/loss moduli, complex viscosity, and elastic modulus were measured at 1.99 Hz, as previously done and reported. , …”

A Manta Ray-Inspired Biosyncretic Robot with Stable Controllability by Dynamic Electric Stimulation

“…For example, the dimensions of the fabricated swimmer were centimeterlevel, which may be too large for in vivo drug transport. Therefore, miniaturization technologies, such as 3D printing and flexible manipulation for micro biological structures [58,59], are necessary for the development of biosyncretic microrobots for clinical applications. Furthermore, most of the existing biosyncretic robots only rely on external artificial stimulations to realize controllable motion and lack autonomy.…”