Pixelated Microfluidics for Drug Screening on Tumour Spheroids and Ex Vivo Microdissected Tumour Explants

SIMPLE SUMMARY: A major challenge in the treatment of cancer is predicting patients’ responses to anticancer drugs. Thus, preclinical assays that reflect patients’ responses to treatments are of utmost importance in clinical oncology and in developing new drugs. 3D tumour models such as spheroids and ex vivo tumour explants are appropriate preclinical models. However, the short-term longevity and low throughput of these models limit their application. To address this, we present a computer-controlled drug screening platform that enables multiplexed delivery of several biochemical reagents such as cellular dyes to 3D tumour models. The platform enables testing up to nine distinct treatment conditions (i.e., nine different biochemical reagents) on more than a hundred 3D tumour models. Moreover, it is compatible with clinical histopathology practice for further manipulation and treatment response analyses of tumour models. ABSTRACT: Anticancer drugs have the lowest success rate of approval in drug development programs. Thus, preclinical assays that closely predict the clinical responses to drugs are of utmost importance in both clinical oncology and pharmaceutical research. 3D tumour models preserve the tumoral architecture and are cost- and time-efficient. However, the short-term longevity, limited throughput, and limitations of live imaging of these models have so far driven researchers towards less realistic tumour models such as monolayer cell cultures. Here, we present an open-space microfluidic drug screening platform that enables the formation, culture, and multiplexed delivery of several reagents to various 3D tumour models, namely cancer cell line spheroids and ex vivo primary tumour fragments. Our platform utilizes a microfluidic pixelated chemical display that creates isolated adjacent flow sub-units of reagents, which we refer to as fluidic ‘pixels’, over tumour models in a contact-free fashion. Up to nine different treatment conditions can be tested over 144 samples in a single experiment. We provide a proof-of-concept application by staining fixed and live tumour models with multiple cellular dyes. Furthermore, we demonstrate that the response of the tumour models to biological stimuli can be assessed using the platform. Upscaling the microfluidic platform to larger areas can lead to higher throughputs, and thus will have a significant impact on developing treatments for cancer.