A rapidly prototyped lung-on-a-chip model using 3D-printed molds

Abstract

Organ-on-a-chip is a microfluidic cell culture model that replicates key organ-specific microarchitecture and pathophysiology in vitro . The current methods to fabricate these devices rely on softlithography, which is usually tedious, laborious, and requires adroit users as well as cleanroom facilities. Recently, the use of 3D-printing technologies for the rapid fabrication of molds for polydimethylsiloxane (PDMS) casting is on the rise. However, most of the 3D-printed materials are unsuitable for PDMS casting. To address this issue, we have improved the existing techniques and introduced a modified protocol for the surface treatment of 3D-printed molds, making them ideal for repeated long-term PDMS casting. Using this protocol, we have fabricated a simple open well lung-on-a-chip model to simulate the in vivo environment of airway at air-liquid interface under dynamic condition. To validate the functionality of the developed chip, Calu-3 cells were cultured in the chip and maintained at an air-liquid interface. The model demonstrated that the cultured cells replicated the 3D culture-specific-morphology, maintained excellent barrier integrity, secreted mucus, and expressed cell surface functional P-glycoprotein; all indicative of a promising in vitro model for permeability assays, toxicological tests, and pulmonary drug delivery studies. To validate the suitability of this lung-on-a-chip in vitro model, the effects of cigarette smoke extract (CSE) on Interleukin-6 (IL-6) and Interleukin-8 (IL-8) release from cultured Calu-3 cells were examined. CSE treated cells showed significantly higher secretion of IL-6 and IL-8 over 24 h compared to the cells treated with both CSE and Budesonide, an anti-inflammatory drug. Moreover, our results illustrated that CSE reduced the expression of E-cadherin as an adherent junctional protein. In conclusion, the proposed protocol demonstrated an easy and low-cost fabrication technique which will allow a biologist with minimal technical skills to rapidly prototype molds for different/versatile organ-on-a-chip models.