100nM

100nM, or one hundred nanomolar, is a concentration unit commonly used in biochemical, pharmacological, and molecular biology research to describe the amount of a substance in solution. A nanomolar concentration is one-billionth of a mole per liter (10⁻⁹ mol L⁻¹). Therefore, 100 nM corresponds to 1.0 × 10⁻⁷ mol L⁻¹. This level of concentration is often chosen to approximate physiological or sub‑toxic exposure levels for signaling molecules, hormones, or small‑molecule drugs.

In receptor binding assays, 100 nM is frequently used as a mid‑point to assess potency (e.g., determining EC₅₀ or IC₅₀ values). Many neurotransmitters (such as acetylcholine or glutamate) and peptide hormones (like insulin or angiotensin II) exhibit significant receptor affinity in the nanomolar range. Pharmaceutical compounds undergoing preclinical profiling are also tested at 100 nM to evaluate efficacy, off‑target interactions, or cytotoxicity in cultured cells. For example, a kinase inhibitor might show inhibitory activity at 100 nM, indicating a strong interaction with its target.

To prepare a 100 nM solution, one typically calculates the required mass of the compound using its molar mass and dilutes it in an appropriate buffer. Accurate pipetting and temperature control are essential because small volumetric errors can disproportionately affect nanomolar concentrations. Analytical techniques such as UV–Vis spectroscopy, mass spectrometry, or high‑performance liquid chromatography are employed to verify the final concentration.

Common applications of 100 nM concentrations include ELISA setups, competitive ligand-binding studies, signal transduction assays, and in vivo dosing simulations. Researchers report results in this unit to facilitate comparison across studies, as it falls within a range that is both biologically relevant and experimentally manageable.