# Nanometer-Resolution Imaging of Living Cells Using Soft X-ray Contact Microscopy
## 3 Cell Imaging with SXCM
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Year** & **X-ray Source** & **Sample** & **Photoresist** & **Imaging** & **Object of Interest** & \multicolumn{2}{c}{**Spatial Resolution (nm)**} & **References** \\ \hline
1981 & X-ray tube & Dry/fixed & PMMA & TEM & Human blood platelets & 5 & ([PERSON] et al., 1981) [49] \\
1985 & Discharge plasma & Hydrated & PMMA & TEM & Human blood platelets & NS * & \\
1990 & Synchrotron & Dry/fixed, isolated & PMMA & TEM & Chromosomes from human & 10 & ([PERSON] et al., 1985) [57] \\
1991 & Laser plasma & Hydrated & PMMA & AFM & Sea urchin sperm & 100 & ([PERSON] et al., 1990) [66] \\
1992 & Laser plasma & Hydrated, isolated & PMMA & TEM & Thymocytes from human & 10–100 & ([PERSON] et al., 1991) [65] \\
1994 & Laser plasma & Hydrated, isolated & PMMA & TEM & Chromosomes from human & 10–100 & ([PERSON] et al., 1990) [66] \\
1997 & Synchrotron & Hydrated & PMMA & AFM & _Candidia albicans_ & 20–90 & ([PERSON] et al., 1991) [65] \\
1998 & Laser plasma & Hydrated & PMMA & AFM & _Pseudomonas aeruginosa_ & 90 & \\
1999 & Laser plasma & Hydrated & PMMA & AFM & Macrophages & - & ([PERSON] et al., 1993) [59] \\
2003 & Laser plasma & Hydrated & EPR & SEM, AFM & Flagella from green algae & 100 & \\
2003 & Laser plasma & Hydrated, isolated & PMMA & AFM & Chromosomes from _Vicia fuba_ L. & 10 & ([PERSON] et al., 1994) [58] \\
2005 & Synchrotron & Hydrated & PMMA & AFM & Macrophages & 10 & ([PERSON] and others, 1997) [63] \\
2011 & Laser plasma & Hydrated & PMMA & AFM & Leydic cells & 90 & ([PERSON] et al., 1997) [63] \\
2012 & Laser plasma & Hydrated & PMMA & AFM & Leydic cells & 100 & ([PERSON] et al., 1997) [64] \\  & & & & & Macrophages, _Leptolyngbu_ sp., & \\
2015 & Laser plasma & Hydrated & PMMA & AFM & _Ch Chlamydomonas reinhardtii_, & 100 & ([PERSON] et al., 1998) [64] \\  & & & & & & & \\
2016 & Laser plasma & Dry/fixed & PMMA & AFM & Non-malignant human bladder cells & 80 & \\
2017 & Laser plasma & Dry/fixed & PMMA & AFM & Human epidermal keratinocytes HEK & 80 & ([PERSON] et al., 1999) [61] \\  & & & & & & Murine colorectal carcinoma CT26, & \\
2017 & Laser plasma & Dry/fixed & PMMA & AFM & human urinary bladder carcinoma & 80 & \\  & & & & & & T24 & \\  & & & & & Human Poieties\({}^{\text{TM}}\) mesenchymal stem & & \\
2020 & Laser plasma & Dry/fixed & PMMA & AFM & cells, breast cancer cells HCC38, & 80 & ([PERSON] et al., 2003) [38] \\  & & & & & prostate cancer cells DU145 & \\
2021 & Laser plasma & Hydrated & PMMA & AFM & Human breast cancer cells HCC38 & 80 & \\
2015 & Laser plasma & Hydrated & PMMA & AFM & _Chlamydomonas reinhardtii_, & 100 & ([PERSON] et al., 2003) [36] \\  & & & & & & & 2003) [36] \\
2016 & Laser plasma & Dry/fixed & PMMA & AFM & Non-malignant human bladder cells & 80 & \\
2017 & Laser plasma & Dry/fixed & PMMA & AFM & Human epidermal keratinocytes HEK & 80 & ([PERSON] et al., 2006) [60] \\  & & & & & Human Poieties\({}^{\text{TM}}\) mesenchymal stem & & \\
2020 & Laser plasma & Dry/fixed & PMMA & AFM & cells, breast cancer cells HCC38, & 80 & \\  & & & & & prostate cancer cells DU145 & & \\
2021 & Laser plasma & Hydrated & PMMA & AFM & Human breast cancer cells HCC38 & 80 & ([PERSON] et al., 2011) [45] \\ \hline  & & & & & & & \\ \end{tabular}
* NS, not specified; PMMA- polymethyl methacrylate; EPR- epoxidized Novolac resist; TEM: transmission electron microscopy; SEM: scanning electron microscopy; AFM: atomic force microscopy.  
\end{table} 
Table 1: Major biological application of soft X-ray contact microscopy. magnitude \"faster\" than PMMA. However, EPR did not enter common use in subsequent research. Nevertheless, from 1980 until 2015, due to the complex experimental procedure, difficulties in the interpretation of the results, the imaging of samples with SEM or TEM (expensive and time-consuming techniques), and the use of synchrotron or advanced laboratory laser systems, only just over a dozen papers presenting original results were published on visualizing biological specimens with SXCM.