Droplet Microarray (DMA) chip for high throughput screening of live cells in nano scale: use-cases for novel read-out methods and functional personalized oncology
Karlsruhe Institute of technology, Baden-Wurttemberg, Germany
Abstract: The DMA platform is founded on the concept of hydrophilic-superhydrophobic patterning, giving rise to a flat, transparent chip capable of creating arrays comprising hundreds of stable and well-separated nanoliter-sized droplets. In recent years, we have successfully showcased the DMA chips' potential in applications related to drug screening involving eukaryotic cells of different nature and sources, including cell lines, primary cells and stem cells. What sets this technology apart is its seamless scalability for droplet miniaturization down to nanoliter volumes, made possible by the planar surface. Moreover, DMA features an open-access design, facilitating the transfer and retrieval of samples, precise temperature control, integration with PCR cyclers, and the utilization of on-chip readout techniques such as MALDI, sample preparation for transcriptomic and proteomic analysis of cells cultured on DMA chips, and label-free impedance-based monitoring of cell behaviour. Our laboratory is actively engaged in refining methodologies for sample preparation on a chip, specifically for omics analysis (transcriptomics and proteomics) of cells cultured on DMA slides with various compounds. In the context of transcriptomics, our workflow involves culturing cells with drugs, cell lysis, mRNA extraction, and subsequent conversion to cDNA. Notably, we incorporate barcoding during the cDNA conversion step, enabling the pooling of content from multiple droplets for subsequent sequencing analysis. We anticipate that these nanoliter-volume, parallelized, and multiplexed read-out methods will provide a novel avenue for analyzing transcriptomic data from drug-treated cells. This approach, combined with the advantages of miniaturization, will allow us to conduct experiments with limited cell samples, including primary cells, shedding light on drug response mechanisms. In another read-out methodology, in collaboration with the Leipzig Institute and Dr. Jahnke, we are working on integrating micro-electrode arrays (MEA) technology and the DMA platform, resulting in eDMA (electrode DMA). This innovation will enable real-time, label-free monitoring of cell activity in nanoliter droplets. Simultaneously, we are partnering with several clinics to develop functional personalized assays. These assays involve testing cancer cells from patients on a chip to assess their sensitivity to various drugs, with the ultimate goal of tailoring anti-cancer therapy for each patient. This approach, coupled with novel label-free and molecular read-out methods, offers the opportunity to investigate drug responses using primary cells, departing from the current reliance on cell lines. Here I will present our last results on mentioned methodologies and use-cases for functional personalized oncology.