Engineering cell-fluorescent ion track hybrid detectors.

Martin Niklas,Claudius Melzig,Jürgen Debus,Steffen Greilich,Oliver Jäkel,Amir Abdollahi,Mark S Akselrod

doi:10.1186/1748-717x-8-141

Abstract

BackgroundThe lack of sensitive biocompatible particle track detectors has so far limited parallel detection of physical energy deposition and biological response. Fluorescent nuclear track detectors (FNTDs) based on Al2O3:C,Mg single crystals combined with confocal laser scanning microscopy (CLSM) provide 3D information on ion tracks with a resolution limited by light diffraction. Here we report the development of next generation cell-fluorescent ion track hybrid detectors (Cell-Fit-HD).MethodsThe biocompatibility of FNTDs was tested using six different cell lines, i.e. human non-small cell lung carcinoma (A549), glioblastoma (U87), androgen independent prostate cancer (PC3), epidermoid cancer (A431) and murine (VmDk) glioma SMA-560. To evaluate cell adherence, viability and conformal coverage of the crystals different seeding densities and alternative coating with extracellular matrix (fibronectin) was tested. Carbon irradiation was performed in Bragg peak (initial 270.55 MeV u−1). A series of cell compartment specific fluorescence stains including nuclear (HOECHST), membrane (Glut-1), cytoplasm (Calcein AM, CM-DiI) were tested on Cell-Fit-HDs and a single CLSM was employed to co-detect the physical (crystal) as well as the biological (cell layer) information.ResultsThe FNTD provides a biocompatible surface. Among the cells tested, A549 cells formed the most uniform, viable, tightly packed epithelial like monolayer. The ion track information was not compromised in Cell-Fit-HD as compared to the FNTD alone. Neither cell coating and culturing, nor additional staining procedures affected the properties of the FNTD surface to detect ion tracks. Standard immunofluorescence and live staining procedures could be employed to co-register cell biology and ion track information.ConclusionsThe Cell-Fit-Hybrid Detector system is a promising platform for a multitude of studies linking biological response to energy deposition at high level of optical microscopy resolution.

Highlights

The lack of sensitive biocompatible particle track detectors has so far limited parallel detection of physical energy deposition and biological response
For A549 cell line, a uniform cell coating were be achieved after longer incubation time using lower plating density (100,000 ml−1)
Given that confocal microscopy is a common method for detection of molecular- and cellular biology parameters, it was hypothesized that development of hybrid detectors will provide a hitherto unmatched correlation of physical with biological parameters at high resolution, only limited by light diffraction [7]

Summary

Introduction

The lack of sensitive biocompatible particle track detectors has so far limited parallel detection of physical energy deposition and biological response. Fluorescent nuclear track detectors (FNTDs) based on Al2O3:C,Mg single crystals combined with confocal laser scanning microscopy (CLSM) provide 3D information on ion tracks with a resolution limited by light diffraction. We report the development of generation cell-fluorescent ion track hybrid detectors (Cell-Fit-HD). We devise a novel strategy to establish a cellfluorescent ion track hybrid detector (Cell-Fit-HD) based on fluorescent nuclear track detectors (FNTDs, Figure 1a). FNTDs based on Al2O3:C,Mg single crystals provide almost 100% detection efficiency of ion tracks imaged by confocal laser scanning microscope (CLSM) [5,6]. We demonstrate the feasibility of sequential read-out of the physical and biological information using CLSM without removing the cell layer from the Al2O3:C,Mg single crystal. The Cell-Fit-HD technology may provide a novel tool for of spatial correlation between biological readouts and single ion traversals

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Conclusion