Assistant Professor Cornell University, United States
Introduction: : The need to manipulate liquid-phase experiments is ubiquitous across biomedical science. Many experiments require systematic combinatorial variation of which factors are present at what concentrations. Despite the notable success of microfluidic approaches in specific applications, most liquid handling is still performed using manual or robotic pipetting. Manual pipetting is prone to high labor costs and errors, while robotic pipetting usually requires substantial capital expenses. Both methods face constraints related to the consumable costs of pipette tips, the minimum volume requirements for expensive reagents and precious samples, and the time required to execute serial liquid manipulations.
Materials and
Methods: : To address these limitations, we introduce Surface Patterned Omniphobic Tiles (SPOTs). This platform combines device geometry and surface engineering to build on discontinuous wetting approaches and leverage capillarity for metering liquids. The SPOTs platform incorporates an omniphobic coating that repels a wide range of liquids, and has two main components: 1) SPOTs plates that selectively repel and attract liquids in predefined patterns, and 2) loading devices that retain and controllably deposit liquids by sliding across the SPOTs plates. (fig. 1a)
Results, Conclusions, and Discussions:: The SPOTs platform allows manipulation of hundreds to thousands of independent experiments without expensive equipment or large consumable costs. For example, figure 1 b-c show how a SPOTs device can create over 1000 different 4-component liquid mixtures in sub-microliter volumes with four pipette tips in several minutes. These devices can handle a wide range of liquid types, across a wide range of volumes (~10 nanoliters to ~10 microliters, fig. 1f), with lower error than standard pipetting. There is no requirement for masks, molds, or photolithography during fabrication, and material costs are minimal. The platform is cross-compatible with existing microwell plate footprints, and, importantly, the technology is fast and intuitive to use. We show how these capabilities enable experiments in diverse experimental systems including testing antibiotic combinations for synergy and antagonism, generating libraries for high-throughput genotyping, and measuring dose-response curves for the inhibition of cell growth from small molecules.
Taken together, these results establish SPOTs as a versatile platform with an unprecedented combination of performance and usability. We anticipate SPOTs will help bring microfluidic advantages to users conducting a wide range of biomedical assays.
Acknowledgements and/or References (Optional):: Shiri, S., Qazi, M. J., Tan, S., Albo, J., Chen, A., Fukuda, R., ... & Cira, N. J. (2024). Surface Patterned Omniphobic Tiles (SPOTs): a versatile platform for scalable liquid handling. bioRxiv, 2024-01.
