Responsive Inverse Opal Scaffolds with Biomimetic Enrichment Capability for Cell Culture

Abstract

<jats:p>Three-dimensional (3D) porous scaffolds have a demonstrated value for tissue engineering and regenerative medicine. Inspired by the predation processes of marine predators in nature, we present new photocontrolled shrinkable inverse opal graphene oxide (GO) hydrogel scaffolds for cell enrichment and 3D culture. The scaffolds with adjustable pore sizes and morphologies were created using a GO and N-isopropylacrylamide dispersed solution as a continuous phase of microfluidic emulsions for polymerizing and replicating. Because of the interconnected porous structures and the remotely controllable volume responsiveness of the scaffolds, the suspended cells could be enriched into the inner spaces of the scaffolds through predator-like swallowing and discharging processes. Hepatocyte cells concentrated in the scaffold pores could form denser 3D spheroids more quickly via the controlled compression force caused by the shrinking of the dynamic scaffolds. More importantly, with a program of scaffold enrichment with different cells, an unprecedented 3D multilayer coculture system of endothelial-cell-encapsulated hepatocytes and fibroblasts could be generated for applications such as liver-on-a-chip and bioartificial liver. It was demonstrated that the resultant multicellular system offered significant improvements in hepatic functions, such as albumin secretion, urea synthesis, and cytochrome P450 expression. These features of our scaffolds make them highly promising for the biomimetic construction of various physiological and pathophysiological 3D tissue models, which could be used for understanding tissue level biology and <jats:italic>in vitro</jats:italic> drug testing applications.</jats:p>

Hydration-Enhanced Lubricating Electrospun Nanofibrous Membranes Prevent Tissue Adhesion

“…Briefly, nanofiber samples were placed into 24-well culture plates and then sterilized in 75% ethanol aqueous solution for 10 min, as well as soaked in PBS supplied with 1% penicillin streptomycin for another 15 min. Finally, the dried samples were sterilized under UV irradiation for another 3 h. NIH/3T3 fibroblasts were used to assess the cell growth on the surface of fibrous membranes [41]. The Dulbecco's modified Eagle's medium (DMEM, 11885084, Gibco, US) culture media supplied with 10% fetal bovine serum (FBS, 10100154, Gibco, US) and 1% penicillin-streptomycin (PS, SV30010, HyClone, US) were used and refreshed every two days.…”

Development of Cell Spheroids by Advanced Technologies

“…[59][60][61] Generally, the scaffolds are prepared by sacrificing microfluidic emulsion droplet templates (single, double, or multiple emulsions). [17] The obtained scaffolds have uniform spherical cavities and are interconnected with each other, which facilitates the transportation of oxygen and nutrients during the cell culture. [17,120] It is worth mentioning that the cell spheroids prepared by these scaffolds have good uniformity, controllable size, and high throughput.…”

“…Based on the above research, the Zhao's team recently proposed for the first time a new type of dynamic stimulusresponsive inverse opal porous scaffold for cell enrichment and 3D cell culture (Figure 5b). [17] The scaffolds with uniform porous structures were produced by removing microfluidic single emulsion (W/O) droplet template, in which graphene oxide (GO) and N-isopropylacrylamide (NIPAM) mixture was the continuous phase, and methyl silicone oil was the dispersed phase. Due to the interconnected pore structures and the lightcontrollable dynamic response of the scaffolds, the suspended cells could be enriched into the interior spaces of the scaffolds.…”

“…Reproduced with permission. [17] Copyright 2019, American Association for the Advancement of Science.…”

“…In addition, cell spheroids have histological properties and can maintain higher levels of tissue-specific function for long periods of time in vitro. [15][16][17] Thence, spheroids have wide applications in the fields of drug development and toxicity screening due to its simplicity, reproducibility, and similarity to physiological tissues. In order to obtain 3D cell spheroids, various methods have been developed, which can be roughly divided into two categories.…”