Fig. 1: Atomic force microscopy (AFM) captures cuticle and stiffness decay of ageing C. elegans. | Nature Communications

Fig. 1: Atomic force microscopy (AFM) captures cuticle and stiffness decay of ageing C. elegans.

From: Mechanical properties measured by atomic force microscopy define health biomarkers in ageing C. elegans

Fig. 1

a Schematics show an AFM laser beam deflection system and a resulting force-indentation curve. The cantilever bends upon increasing force detected by the deflection of the laser beam reflected from the cantilever back onto a photodiode (left). Typical AFM force-indentation approach curve indicating stages of tip-sample interaction shown in blue (right). b Lifespan curve of wild-type (WT) C. elegans (n = 222). Arrows indicate time points at which AFM measurements were performed—day 1, 5, 8, 12, 15 and 18 of adulthood. c Mechanical properties as Young’s Modulus (YM; kPa) of WT C. elegans at different ages. Error bars indicate 95% confidence intervals (CI), dotted line marks mean YM at day 1. d Lifespan curve of WT C. elegans grown at 20 °C and maintained at 15 °C (blue), 20 °C (yellow) or 25 °C (red) from the L4 stage throughout their entire lifespan (n = 148, 99, 89, respectively; log rank test p < 0.001 vs 20 °C) and e mechanical properties as YM (kPa) at day 15. Error bars indicate 95% CI. Two-tailed unpaired t test for statistical comparison of WT at 20 °C to 15 °C or 25 °C. f Representative AFM cuticle topography images of ageing C. elegans at different ages. g Roughness quantification of topographical images presented as RMS roughness Rq ± standard deviation. Two-tailed unpaired t test for statistical comparison with day 1. h Three-dimension representation of AFM cuticle topography of C. elegans on day 1 and 19 of adulthood. n represented above the graph, show number of biologically independent worm samples; For lifespan measurements, n represents the number of worms scored as dead. For a summary of YM values and additional statistics for independent trials see Supplementary Data 1 and for a summary of worm lifespan trials see Supplementary Data 2. Source data are provided as a Source Data file.

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