中性红指示剂 Neutral Red Indicator

中性红是一种弱碱性 pH 指示剂，变色范围 pH6.4～8.0之间（由红变黄）。在中性或微碱性环境中，植物的活细胞能大量吸收中性红并向液泡中排泌，由于液泡在一般情况下呈酸性反应，因此，进入液泡的中性红便解离出大量阳离子而呈现樱桃红色，在这种情况下，原生质和细胞壁一般不着色；死细胞由于原生质变性凝固，细胞液不能维持在液泡内，因此，用中性红染色后，不产生液泡着色现象，相反，中性红的阳离子，却与带有一定负电荷的原生质及细胞核结合，而使原生质与细胞核染色。

酸碱指示剂，pH 6.8(红)～8.0(黄)；水、亚硝酸盐和尿的碱度指示剂；组织化学中用于脂肪的水解指示剂；神经细胞的尼尔(Nissl)小粒染色；与健那绿共用于血液体外活体染色；碘离子的光度测定；中性红试纸的制备。

运输与保存：常温运输，12个月

PH1857 "中性红指示剂 (0.1%)
Neutral Red Indicator" 指示剂 100mL/500mL


PH1858 "中性红指示剂 (0.05%)
Neutral Red Indicator" 指示剂 100mL/500mL

Neutral red (toluylene red, Basic Red 5, or C.I. 50040) is a eurhodin dye used for staining in histology. It stains lysosomes red.[1] It is used as a general stain in histology, as a counterstain in combination with other dyes, and for many staining methods. Together with Janus Green B, it is used to stain embryonal tissues and supravital staining of blood. Can be used for staining Golgi apparatus in cells and Nissl granules in neurons.

In microbiology, it is used in the MacConkey agar to differentiate bacteria for lactose fermentation.

Neutral red can be used as a vital stain. Live cells incorporate neutral red into their lysosomes. As cells begin to die, their ability to incorporate neutral red diminishes. Thus, loss of neutral red uptake corresponds to loss of cell viability.[2] It is also used to stain cell cultures for plate titration of viruses.[2]

Neutral red is added to some growth media for bacterial and cell cultures. It usually is available as a chloride salt.

Neutral red acts as a pH indicator, changing from red to yellow between pH 6.8 and 8.0.


References
^ Winckler, J. Vital staining of lysosomes and other cell organelles of the rat with neutral Red. Prog. Histochem. Cytochem. 6, 1–89 (1974).
^ a b RepettoG, del Peso A, Zurita JL. Neutral red uptake assay for the estimation of cellviability/cytotoxicity. Nat Protoc. 2008;3(7):1125–1131.doi:10.1038/nprot.2008.75.