Microfluidic Droplet‐Based Tailorable Porous GelMA Microspheres for 3D Spatio Controllable Cell Coculture

Abstract

For the construction of accurate 3D tissue models in vitro, the 3D coculture model formed by spatio‐controlled distribution of multiple cells is essential. Despite the benefits of porous microspheres with low density, large surface area, and high permeability, exact spatio‐controlled distribution fails to appear in 3D coculture models by using porous microspheres as carriers. Herein, a facile method is proposed to construct a 3D coculture model with heterogeneous cell spatio‐tailored distribution using GelMA microspheres with customizable porosity structure and size based on droplet microfluidics in combination with placeholders. ATPS emulsions, containing two biocompatible immiscible aqueous phases of cell/Alg /dextran (Dex) mixture and polyethylene glycol (PEG) solution, are used as the templates to generate the placeholders. The micron‐sized porous GelMA microspheres are prepared by UV crosslinking of droplets prepared in microfluidic devices, followed by chelation of the placeholders. As a proof of concept, the 3D coculture hepatocellular carcinoma (HCC) model with HepG2 encapsulated outside the pores and HUVEC inside the pores is established. Noteworthy, the cells in the 3D coculture HCC model exhibit greater cell activity and proliferation, enhanced functionalities, and drug resistance than the control group. In conclusion, this straightforward method provides a novel approach for constructing 3D coculture models in vitro.

Preparation of Controlled Multicompartmental Gel Microcarriers Based on Aqueous Two-Phase Emulsions for 3D Partitioned Cell Coculture In Vitro

“…18,20 Compared to other materials such as GelMA and PuraMatrix, alginate exhibits the unique characteristics such as natural origin, mild gel formation condition, and versatile modifiability. 21,22 In our group's previous research, we found that by dissolving Alg in Dex solutions, porous Alg microspheres that directly encapsulate the cells were formed in the PEG-CaCl 2 collection solution by using the dripping method. 18 Based on the above reasons, we hypothesized that multicompartmental gel microcarriers could be prepared by controlling the fusion of Dex-Alg droplets in the doublelayered collection solutions comprising an upper PEG solution and a lower Dex-CaCl 2 solution.…”

“…Furthermore, the disposal of waste oil poses environmental concerns and requires professional treatment before discharge, thereby raising costs. An aqueous two-phase system (ATPS) referred to a two-phase system formed by mixing two incompatible aqueous solutions, typically with polymers, salts, or other additives dissolved in water, where under specific conditions water separated into two distinct phases. − Due to the extremely high biocompatibility of the two aqueous phases, it had been proven to be used in cell culture studies in vitro. , Alginate (Alg) serves as a commonly used 3D coculture material with many advantages in cell culture and tissue engineering fields. , Compared to other materials such as GelMA and PuraMatrix, alginate exhibits the unique characteristics such as natural origin, mild gel formation condition, and versatile modifiability. , In our group’s previous research, we found that by dissolving Alg in Dex solutions, porous Alg microspheres that directly encapsulate the cells were formed in the PEG-CaCl 2 collection solution by using the dripping method . Based on the above reasons, we hypothesized that multicompartmental gel microcarriers could be prepared by controlling the fusion of Dex-Alg droplets in the double-layered collection solutions comprising an upper PEG solution and a lower Dex-CaCl 2 solution.…”