Acidic Tyrode's solution

NaCl, 0.8 g

KCl, 0.02 g

CaCl₂•2H₂O, 0.024 g

MgCl₂•6H₂O, 0.01 g

Glucose, 0.1 g

Polyvinylpyrrolidone (PVP), 0.4 g

Dissolve the above ingredients in 100 ml of H₂O. Prepare at room temperature and adjust to pH 2.5 with Analar HCl (BDH). The PVP is added to increase viscosity and reduce embryo stickiness. Filter-sterilize and store in aliquots at -20°C. Acidic Tyrode’s is also available from Sigma and Specialty Media.