Abstract
Purpose:
Effective cell sorting technologies are of great interest for both clinical and research purposes. Acoustophoresis holds great promise as a cell separation technique and here we investigate whether it can be used to sort primary post-natal retinal cells and assess the eventual effects on cell viability and retinal phenotypes. One aim is to separate the photoreceptors and ganglion cells from the other retinal cells. The method uses acoustic forces to manipulate cells at the microfluidic scale, and enables a gentle, non-contact, label-free separation based on intrinsic cell properties, including size, density and compressibility.
Methods:
Mouse retinas from post-natal day 4 were dissected and dissociated into a single cell suspension. A microfluidic acoustophoresis chip allowing separation of cell populations was used. For sorting, cells were transferred to a 4 mM EDTA PBS solution. Initially different strengths of the acoustic field (between 3V and 11V) are tested to determine separation potential of the primary cells after acoustophoresis and thereby, to separate photoreceptors and ganglion cells from other retinal cells. Cell numbers and survival of the sorted cells are measured. Changes in phenotype of the sorted cells are studied at 7 and 18 days after seeding, using fluorescent immunostainings with markers specific for the retinal glial- and neuronal cell types. Non-sorted dissociated and cultured cells and the retina of corresponding age in vivo serve as controls.
Results:
Initial experiments demonstrate very good survival of all the sorted cell fractions, immediately after sorting as well as up to 18 days in culture (corresponding to day 22 in vivo). In addition, the sorted cells display complex neuronal- and glial phenotypes comparable with the cultured corresponding non-sorted cells. The retinal cells can indeed be sorted into different fractions, judged from preliminary results showing especially different numbers of neurons and different neuronal profiles in the various fractions.
Conclusions:
We conclude that post-natal retinal cells can be sorted into subfractions with a high viability and a maintained ability to form glial- and neuronal phenotypes in culture. Further studies will reveal if specific cell types can be sorted. A successful sorting method for post-natal retinal cells can be very useful in e.g. the development of novel cell replacement approaches for retinal degenerative diseases.
Keywords: 500 differentiation •
688 retina •
687 regeneration