NP‑40 Lysis Buffer is a widely used non‑ionic detergent‑based reagent formulated to gently disrupt cell membranes for protein extraction and analysis. It efficiently solubilizes cellular and organelle membranes without excessive denaturation, making it a preferred choice for preparing samples for immunoprecipitation, Western blotting, and other immunoassays. Compared to stronger formulations such as RIPA buffer, this NP‑40 buffer provides a milder lytic environment that permeabilizes plasma membranes and partially releases nuclear contents while preserving protein–protein interactions and subcellular integrity.