Noninvasive and safe cell viability assay for Paramecium using natural pigment extracted from food

Abstract

Noninvasive, safe and cost-effective cell viability assay is important in many fields of biological research such as cell culture and counting. We examined ten typical natural pigments extracted from food to find that Monascus pigment (Mp) or anthocyanin pigment (Ap: purple sweet potato and purple cabbage) with tris (trimethylolaminomethane) works as a good indicator of viability assay for dye exclusion test (Det) of Paramecium. This was confirmed spectrally by scan-free, non-invasive absorbance spectral imaging A (x, y, λ) microscopy. We developed a new method of cell capture using a metal mesh to confine live Paramecium in a restricted space. this has the advantage that a low-cost and robust capture can be fabricated without using special equipment, compared to a conventional lab-on-a-chip. As a result, Mp and Ap stained dead cells as quick as methylene blue (MB), a synthetic dye conventionally used in DET within 1 min when treated with microwave and benzalkonium chloride. The natural pigments with Tris had little effect on inhibiting the growth of Paramecium, but MB killed all the cells within 1 h. MP is most useful because it allows non-invasive DET without Tris. this approach provides less invasive and safe Det.

Noninvasive and Safe Cell Viability Assay for Breast Cancer MCF-7 Cells Using Natural Food Pigment

“…The mechanism of staining with TB also results from binding to intracellular proteins [ 14 ]. In the preceding papers on DET of Euglena and Paramecium , long-term viability could be determined with anthocyanin pigments (purple sweet potato and red cabbage dye) in addition to MP [ 28 , 34 ]. This was thought to be due to differences in cell structure.…”

“…Here, the component of “Food pigment Red” contains 95% w / w dextrin by weight, and the remaining 5% is pure MP. However, in the preceding papers that used Euglena and Paramecium as samples [ 28 , 34 ], the concentration of “Food pigment Red” was described as the concentration of “MP”. (Cf.…”

“…Regarding the quality assurance of MP, it is based on the component standards in the Japan’s Specifications and Standards for Food Additives (JSFA) [ 27 ]. The details are described in the article of the example applied to Paramecium [ 28 ].…”

“…To verify that this method is applicable to a wide variety of cells, first, we examined whether natural pigments are not toxic to human breast cancer cells MCF-7 cells in the presence or absence of cisplatin and if they can be replaced with conventional synthetic dyes for viability assay. Then, the effect of natural pigments on cells with different properties was investigated, and the results were compared between the unicellular green alga Euglena [ 34 ] and the protozoan Paramecium [ 28 ], which differ in cell structure.…”

Ecological and Biotechnological Aspects of Pigmented Microbes: A Way Forward in Development of Food and Pharmaceutical Grade Pigments

“…In contrast, bacterial pigments like prodigiosin and violacein are used to color papers, candles, soaps, ink, clothes [ 271 ], and textile dyeing [ 272 ]. Monascus pigment or anthocyanin pigment are employed as noninvasive dye indicators in safe cell viability assay for Paramecium [ 273 ], Euglena [ 274 ], and breast cancer cells [ 275 ]. Microbes isolated from cryosphere environments also produced various pigments with multifaceted applications [ 269 , 276 , 277 ], including anticancer activities [ 278 ].…”