Phosphate-Buffered Saline (PBS) for HCR (10×, pH 7.4)

1.37 m NaCl

27 mm KCl

80 mm Na₂HPO₄

20 mm KH₂PO₄

To prepare 1 L of a 10× stock solution, combine 80 g of NaCl (Sigma-Aldrich S3014), 2 g of KCl (Sigma-Aldrich P9541), 11.4 g of Na₂HPO₄ (anhydrous; Sigma-Aldrich S3264), and 2.7 g of KH₂PO₄ (anhydrous; Sigma-Aldrich P9791). Adjust the pH to 7.4 with HCl, and bring the final volume to 1 L with ultrapure H₂O. Avoid using CaCl₂ and MgCl₂ in PBS for HCR. It is important that the PBS for HCR is prepared as an RNase-free solution (e.g., via diethylpyrocarbonate [DEPC] treatment).

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