Extended Data Fig. 2: Quantifying cavity pressure in mouse embryos using a micropressure probe.
From: Hydraulic control of mammalian embryo size and cell fate
a, b, Characteristics of successful cavity pressure measurements. Top, images showing two mouse blastocysts before and during pressure measurement. The baseline reading is close to zero when the microelectrode (0.5 μm) is not in contact with the blastocysts. A transient pressure spike is recorded as the tip of the microelectrode penetrates the zona pellucida. This is followed by a stable reading for about 5–10 s, before some potential leaks occur, which may cause a gradual drop in the reading with time. c, d, Proof-of-principle experiments to verify the pressure measurement. c, The addition of Bb(−) (25 μM) leads to a transient reduction in cavity size and pressure within 10 s. d, The accuracy of the device was further demonstrated by comparing the cytoplasmic pressure of mouse oocytes at the germinal vesicle (GV) stage, measured directly by the micropressure probe and indirectly by Laplace’s law though micropipette aspiration (Pc = 2γ/R, in which γ is the cortical tension of the oocyte measured by micropipette aspiration, and R is the radius of the oocyte). Data obtained by both approaches are not significantly different (Mann–Whitney U test). N, number of oocytes. Scale bars, 20 μm. All data show representative examples from three or more independent experiments.
