Laser-emission vibrational microscopy of microdroplet arrays for high-throughput screening of hyperlipidemia.

The mechanical properties of biological fluids serve as early indicators of disease, offering valuable insights into complex physiological and pathological processes. However, the existing technologies struggle to achieve high-throughput measurement, limiting their widespread applications in disease diagnosis. Here, we propose laser-emission vibrational microscopy of microdroplets for high-throughput measurement of the intrinsic mechanical properties of fluids. The microdroplet array supporting high Q-factor (104) whispering gallery modes (WGM) lasing was massively fabricated on a superhydrophobic surface with inkjet printing. Ultrasound was employed to actuate the mechanical vibrations of the microdroplets, and the vibration amplitude was quantified using time-resolved laser spectra. We found that the stimulus-response of the laser emission is strongly dependent on the liquid viscosity. Fast mapping of the microdroplets' viscosities was achieved by stage scanning. High-throughput screening of hyperlipidemia disease was also demonstrated by performing over 2000 measurements within 25 min. Thanks to the small volume of the microdroplets, a single drop of blood can support over seven million measurements. The high-throughput ability and small sample consumption make it a promising tool for clinical diagnoses based on mechanical properties.