Harnessing endogenous signals from hepatocytes using a low volume multi-well plate

Current Advances on 3D-Bioprinted Liver Tissue Models

The liver, the largest gland in the human body, plays a key role in metabolism, bile production, detoxification, and water and electrolyte regulation. The toxins or drugs that the gastrointestinal system absorbs reach the liver first before entering the bloodstream. Liver disease is one of the leading causes of death worldwide. Therefore, an in vitro liver tissue model that reproduces the main functions of the liver can be a reliable platform for investigating liver diseases and developing new drugs. In addition, the limitations in traditional, planar monolayer cell cultures and animal tests for evaluating the toxicity and efficacy of drug candidates can be overcome. Currently, the newly emerging 3D bioprinting technologies have the ability to construct in vitro liver tissue models both in static scaffolds and dynamic liver-on-chip manners. This review mainly focuses on the construction and applications of liver tissue models based on 3D bioprinting. Special attention is given to 3D bioprinting strategies and bioinks for constructing liver tissue models including the cell sources and hydrogel selection. In addition, the main advantages and limitations and the major challenges and future perspectives are discussed, paving the way for the next generation of in vitro liver tissue models.

High-throughput cell migration assay under combinatorial chemical environments by a novel 24-well-plate based device

The quantitative studies of cell proliferation and migration under different chemical environments are important for both scientists and clinicians searching for new therapeutics. In this study, we developed a new device to pattern several types of cells in 24-well-plate and demonstrated its' application in cancer cell proliferation and migration assay. The new device combined 3D-printed-silica-part for multi cell types loading with PDMS-through-hole-layer-part for cell micro-patterning which was matched with commercial 24-well-plate. This 24-well-plate based device is flexible and feasible in many applications and can be used in one piece or multi pieces. Besides the application for two types of cells proliferation and migration assay in one chemical condition, as a demonstration, the migration behaviors of four types of cells under 24 types of EGF + bFGF combinatorial conditions were studied. We believed this device could be widely used in clinical searching for new anti-cancer therapeutics and other related studies.

Liver Tissue Engineering: Challenges and Opportunities

Liver tissue engineering aims at the possibility of reproducing a fully functional organ for the treatment of acute and chronic liver disorders. Approaches in this field endeavor to replace organ transplantation (gold standard treatment for liver diseases in a clinical setting) with in vitro developed liver tissue constructs. However, the complexity of the liver microarchitecture and functionality along with the limited supply of cellular components of the liver pose numerous challenges. This review provides a comprehensive outlook onto how the physicochemical, mechanobiological, and spatiotemporal aspects of the substrates could be tuned to address current challenges in the field. We also highlight the strategic advancements made in the field so far for the development of artificial liver tissue. We further showcase the currently available prototypes in research and clinical trials, which shows the hope for the future of liver tissue engineering.

Upgrading well plates using open microfluidic patterning

Cellular communication between multiple cell types is a ubiquitous process that is responsible for vital physiological responses observed in vivo (e.g., immune response, organ function). Many in vitro coculture strategies have been developed, both in traditional culture and microscale systems, and have shown the potential to recreate some of the physiological behaviors of organs or groups of cells. A fundamental limitation of current systems is the difficulty of reconciling the additional engineering requirements for creating soluble factor signaling systems (e.g., segregated cell culture) with the use of well-characterized materials and platforms that have demonstrated successful results and biocompatibility in assays. We present a new open-microfluidic platform, the Monorail Device, that is placed in any existing well plate or Petri dish and enables patterning of segregated coculture regions, thereby allowing the direct upgrade of monoculture experiments into multiculture assays. Our platform patterns biocompatible hydrogel walls via microfluidic spontaneous capillary flow (SCF) along a rail insert set inside commercially available cultureware, creating customized pipette-accessible cell culture chambers that require fewer cells than standard macroscale culture. Importantly, the device allows the use of native surfaces without additional modification or treatments, while creating permeable dividers for the diffusion of soluble factors. Additionally, the ease of patterning afforded by our platform makes reconfiguration of the culture region as simple as changing the rail insert. We demonstrate the ability of the device to pattern flows on a variety of cell culture surfaces and create hydrogel walls in complex and precise shapes. We characterize the physical parameters that enable a reproducible SCF-driven flow and highlight specialized design features that increase the ease of use of the device and control of the open microfluidic flow. Further, we present the performance of our platform according to useful coculture criteria, including permeability and integrity of our hydrogel walls and surface-sensitive cell culture. Lastly, we show the potential of this type of platform to create modular multikingdom culture systems that can be used to study soluble factor signaling between mammalian cells, bacteria, and fungi, as well as the potential for adaptation of this technology by researchers across multiple fields.