Each organ-on-a-chip model is always accompanied by common laboratory equipment to carry out assays, such as pumping and fluid control systems, sensor readout systems, incubators and imaging tools. Even though organ-on-chip devices comprise of the same functional elements (microfluidic channels, culture chambers, hydraulic valves, integrated sensors etc.), there’s an inherent lack of compatibility with peripheral laboratory equipment across devices produced by different developers. This is exacerbated by the fact that commercial devices are often made uniquely compatible with a family of other products and/or platforms produced and marketed by the same manufacturer. These platforms do offer the ability to manage multiple devices for high throughput assays, but they have different sizes and layouts and cannot be easily interfaced with one another. Inevitably, this forces researchers to purchase an entire family of products from the same supplier, which is often too expensive, and also limits research to cell-lines and barrier membranes uniquely compatible to that platform.
To overcome this challenge, the European Organ-on-Chip Society recommends the establishment of Open technology platforms where the devices themselves (size and footprint) and their interfaces with existing laboratory equipment and workflows are standardised. This could greatly boost the implementation of organ-on-a-chip devices by smaller groups, whilst retaining the unique functional elements of their devices which are critical to their particular purpose.
A major step in the right direction was the introduction of ISO 22916:2022, Microfluidic devices — Interoperability requirements for dimensions, connections and initial device classification. As outlined in the Scope of this document, it “specifies requirements for the seamless integration with other microfluidic components and systems to facilitate the process of designing new microfluidic devices (e.g. microfluidic chips, sensors, actuators, connectors)”. Specifically, it specifies chip reference points, topology, dimensions, top and side connections.
Following the same ethos, the University of Twente is developing the Translational Organ-on-chip Platform (TOP), which is designed to provide a common infrastructure for automated microfluidic chip control, which can be adapted to various devices provided that they follow simple design rules based on ISO 22916:2022. TOP implements a multi-layer approach where custom chips and flow control boards featuring valves and clamps are assembled as stackable modules via common design features.
With regards to integration of sensors, the same modular approach is utilised by Moore4Medical’s Smart Multi-Well Plate for interfacing sensors and electrodes for live measurements, where the transducers and electrodes are embedded as an additional layer. Other active components needed for assays such as heaters or electrowetting electrodes can be integrated in a similar multi-layer modularity fashion. Cable connectivity and controller/data-logger interfacing should also be standardised. The European Committee for Standardisation recommends simple USB connections but highlights the need to add these features with careful consideration of the fluidic control system, incubator conditions and other factors that could influence sensor performance.
Standard solutions for making organ-on-a-chip devices compatible with imaging platforms are necessary for the analysis phase of assays. A transparent bottom providing optical access is seen across almost all devices, but securely mounting the device on the imaging platform is also crucial when physically accessing the chip to streamline the assay processes. Therefore, standard dimensions and tolerances of common labware, such as multi-well plates and glass slides, should be inherited into dimensional standards for chips.