CrystalloDisc: A self-actuating and high-throughput engine for intelligent protein crystal screening

We introduced a multi gradient-based lab-on-a-disc for high-throughput (HTP) protein crystallization screening (Multi-ProD). The single chip enables simultaneous control of 3 distinct key parameters: protein concentration, precipitant type, and precipitant concentration across 36 microreactors. A customized 3D-printed cartridge integrated with 4 parallel siphon-based spiral structures allows rapid, automatic metering of microliter-scale volumes and ensures easy solution release into microreactors through centrifugal profile control under 5 min. The chip's capability for systematic screening and comparison of crystallization conditions was demonstrated using various precipitants, including NaCl, KBr, Mg(CH₃COO)₂.4H₂O, MnCl₂, and CaCl₂. Among these, CaCl₂ showed superior performance by producing larger crystals with shorter induction times, highlighting the potential of this microfluidic chip in determining effective crystallization conditions for protein crystallography.