, ▁and ▁st ain ▁ 1 5 - 3 0 ▁prote ins ▁to ▁measure ▁their ▁location ▁and / or ▁relative ▁abund ance . ▁Image ▁cy cling ▁techniques ▁have ▁been ▁developed ▁to ▁measure ▁multi - target ▁abund ance ▁and ▁distribution ▁in ▁bi ops y ▁samples ▁and ▁t issues . ▁In ▁these ▁methods , ▁ 3 - 4 ▁targets ▁are ▁st ained ▁with ▁flu ores cent ly ▁l abeled ▁ant ib od ies , ▁im aged , ▁and ▁then ▁stri pped ▁of ▁their ▁flu or op hor es ▁by ▁a ▁variety ▁of ▁means , ▁including ▁ox id ation - based ▁chem ist ries ▁or ▁more ▁recently ▁ant ib ody - D NA ▁conjug ation ▁methods , ▁allowing ▁additional ▁targets ▁to ▁be ▁st ained ▁in ▁follow - on ▁cycles ; ▁in ▁some ▁methods ▁up ▁to ▁ 6 0 ▁individual ▁targets ▁have ▁been ▁visual ized . ▁For ▁surface ▁methods , ▁research ers ▁place ▁a ▁single ▁cell ▁on ▁a ▁surface ▁co ated ▁with ▁ant ib od ies , ▁which ▁then ▁bind ▁to ▁prote ins ▁secret ed ▁by ▁the ▁cell ▁and ▁allow ▁them ▁to ▁be ▁measured . ▁Micro fl uid ics ▁methods ▁for ▁prote ome ▁analysis ▁imm obil ize ▁single ▁cells ▁on ▁a ▁micro ch ip ▁and ▁use ▁st aining ▁to ▁measure ▁the ▁prote ins ▁of ▁interest , ▁or ▁ant ib od ies ▁to ▁bind ▁to ▁the ▁prote ins ▁of ▁interest . ▁ ▁Vari ation ▁in ▁cell ▁size ▁and ▁morph ology ▁C ells ▁in ▁an ▁otherwise ▁similar ▁population ▁can ▁vary ▁in ▁their ▁size ▁and ▁morph ology ▁due ▁to ▁differences