Laser plasma x-ray contact microscopy of living specimens

We report on the use of an epoxy novolac chemically amplified photoresist to produce X-ray images of living biological specimens in the water window using laser plasma generated soft X-rays (2.4 - 4.4 nm). The photoresist response was at least one order of magnitude `faster' than the standard PMMA (polymethyl methacrylate) previously used in soft X-ray contact microscopy. After chemical development of the exposed resists, atomic force microscopy (AFM) of the relief images obtained of biological specimens clearly showed the flagella of the motile green alga, Chlamydomonas, suggesting a lateral resolution better than 200 nm, whilst the AFM was capable of discriminating height features of 20 nm in depth profiles.