Application and utility of alternative methods in isolation of pure cells from forensic biological mixtures in modern-day: a review

Development of genetic profiles from the biological mixtures has remained challenging, although modern-day technologies may help forensic scientists to attain a reliable genetic profile in the identification of the accused. In the case of rape, vaginal swab exhibits usually contain epithelial cells of victims and sperm cells of accused, such samples are more challenging when there is more than one contributor. In such cases, separation of distinct cells from a mixture that includes blood cells, epithelial cells and sperm cells for their single genetic profile is important. In the last ten decades several new techniques were developed and invented for the separation of single cell from the biological mixture that includes differential lysis, laser micro-dissection, cell sorting (FACS), sieve-based filtration, (vi) micro-fluidic devices or immunomagnetic beads cell separation of fresh samples, and the magnetic activated cell sorting (MACS). Out of them, some techniques have been commonly applied for cell separation in forensic biology. Each technique has its own limitation. Some recent studies showed, magnetic activated cell sorting (MACS), laser capture microdissection (LCM), DEPArray technology and fluorescence activated cell sorting (FACS) has proved to be effective in separation of single cell from cell mixtures. Therefore, in this review we have evaluated these four alternative methods and their potential application in the modern-day over the others for the separation of a single cell from the mixture. In this review we also discuss the advantage of these methods and their modern–day applicability and acceptance in the forensic world.