Thompson Street Capital Partners has announced it has acquired Vector Laboratories.

Vector, based in Burlingame, Calif., is the protein detection business unit of Maravai. Founded in 1976, the company manufacturers labeling and visual detection reagents for life science researchers conducting tissue-based protein detection and characterization.

Thompson Street Capital Partners, based in St. Louis, Mo., targets investments in middle market companies. Founded in 2000, the firm typically invests in healthcare and a few other sectors. Within healthcare, areas of interest include pharmaceutical logistics, connected health, and regulatory and compliance.

Terms of the acquisition were not disclosed.