MicroTesla-Driven 3D Printed Microfluidic Platform for Co-Culturing Adipocytes and Beta INS1 Cells in Diabetes and Hypoxia

Abstract

The global surge in obesity has intensified interest in hypoxia as a crucial factor in the development of obesity and its associated health issues. This has prompted the exploration of hypoxia as a potential therapeutic strategy for managing obesity and its complications. Both diabetes and hypoxia can become life-threatening when they disrupt normal physiological functions. Hypoxia, a condition where tissues receive inadequate oxygen, often results from cardiovascular or respiratory disorders. In diabetes, hypoxia may occur due to poor blood circulation, amplifying issues such as foot ulcers, slow wound healing, and organ damage. The interplay between diabetes and hypoxia creates a vicious cycle: impaired oxygen delivery worsens metabolic dysfunction, and diabetic complications further intensify hypoxia. This interaction increases the risk of severe outcomes like heart attacks, strokes, and limb amputations, making both conditions significant contributors to mortality if left untreated. To gain deeper insight into the complex mechanisms and interactions of diabetes and hypoxia, researchers are continually developing in vitro and in vivo models. Microfluidics has emerged as a promising technology in this field, allowing precise control of cellular and tissue environments to replicate the pathological conditions of diseases. These ""disease-on-a-chip"" devices simulate the microenvironments of tissues affected by diabetes and hypoxia. By integrating cell and tissue engineering, advanced materials, and on-chip biosensing technologies, microfluidics offers a dynamic and physiologically relevant platform for biomedical research on these conditions. The central hypothesis is that understanding the interaction between diabetes and hypoxia under the influence of shear stress can provide essential insights into their complex mechanisms using disease-on-a-chip devices. Three key questions were addressed to achieve the research objectives: (1) How can continuous, non-pulsatile, and recirculating flow be tailored for modeling flow shear stress (FSS)? (2) How do blood shear forces modulate adipose tissue-derived cytokines, leading to beta-cell dysfunction and type 2 diabetes (T2D)? (3) How does hypoxia induce insulin resistance and beta-cell dysfunction under shear stress in diabetic individuals? To investigate these questions, the µTesla pump was first designed using AutoDesk Inventor and optimized using COMSOL simulations to achieve a flow rate of 1 mL/min, which mimics pancreatic blood flow. A microfluidic device featuring two embedded µTesla pumps was fabricated via 3D printing using fused deposition modeling (FDM). The device was constructed with two chambers to co-culture adipocytes and INS1 cells under normoxic and hypoxic conditions. The results demonstrated that the co-culture environment mitigated the effects of TNF-α on adiponectin secretion and promoted calcium and insulin secretion from INS1 cells, driven by IL-6 from adipocytes. Under diabetic and hypoxic conditions with shear stress, the interaction between INS1 cells and adipocytes enhanced adiponectin secretion while suppressing TNF-α, influenced by the increased secretion of IL-6 from adipocytes and insulin from INS1 cells. Overall, this research advances our understanding of the interplay between adipocyte-secreted inflammatory cytokines and INS1 cell responses (insulin and calcium secretion) in the context of hyperglycemia and hyperinsulinemia. It also highlights the integration of mechanical engineering techniques, such as 3D printing and numerical simulations, to advance the field of disease-on-chip technology, with potential implications for manufacturing and medical research industries.