Microfluidic Organ-on-A-chip: A Guide to Biomaterial Choice and Fabrication

Abstract

Organ-on-a-chip (OoAC) devices are miniaturized, functional, in vitro constructs that aim to recapitulate the in vivo physiology of an organ using different cell types and extracellular matrix, while maintaining the chemical and mechanical properties of the surrounding microenvironments. From an end-point perspective, the success of a microfluidic OoAC relies mainly on the type of biomaterial and the fabrication strategy employed. Certain biomaterials, such as PDMS (polydimethylsiloxane), are preferred over others due to their ease of fabrication and proven success in modelling complex organ systems. However, the inherent nature of human microtissues to respond differently to surrounding stimulations has led to the combination of biomaterials ranging from simple PDMS chips to 3D-printed polymers coated with natural and synthetic materials, including hydrogels. In addition, recent advances in 3D printing and bioprinting techniques have led to the powerful combination of utilizing these materials to develop microfluidic OoAC devices. In this narrative review, we evaluate the different materials used to fabricate microfluidic OoAC devices while outlining their pros and cons in different organ systems. A note on combining the advances made in additive manufacturing (AM) techniques for the microfabrication of these complex systems is also discussed.

Breaking the clean room barrier: exploring low-cost alternatives for microfluidic devices

“…Additionally, these hydrogels exhibit optical transparency, allowing visualization of internal microfluidic device components. These features render hydrogels particularly well-suited for use in lab-on-a-chip and organs-on-a-chip systems, especially in the context of biosensing and drug delivery applications ( Hou et al, 2017 ; Nie et al, 2020 ; Ma et al, 2022 ; Sood et al, 2022 ; Cao et al, 2023 ).…”

Complex in vitro model: A transformative model in drug development and precision medicine

“…Finally, the optical transparency, fabrication difficulty, mechanical properties, and cost also need to be considered. 72 The PDMS is extensively utilized in microfluidic devices due to its transparency, ease of fabrication, and biocompatibility. Its diminished affinity for hydrophobic drugs renders it suitable for drug screening and delivery investigations.…”

“…Besides, materials like natural biomaterials (represented by gelatin, alginate, and collagen), PLGA, et al. are used to fabricate microfluidic chips 72 …”

“…Materials with high binding affinity or drug adsorption properties with drugs and detection reagents can interfering with the results of drug screening or basic medicine research. Finally, the optical transparency, fabrication difficulty, mechanical properties, and cost also need to be considered 72 …”

Breast tumor-on-chip: from the tumor microenvironment to medical applications

“…76 Although soft lithography technology serves as the foundation for chip fabrication with high resolution and ease of replication, it still has limitations. 77 For example, PDMS can absorb small molecules and hydrophobic molecules, leading to inaccurate drug dosing and interfering with drug analysis. 78 In addition, soft lithography is a multi-step process and requires extensive manual handling, limiting time and cost.…”