Transwell Assay

The Transwell assay (also called the Boyden chamber assay after its originator Stephen Boyden) is a quantitative method for measuring cell migration and invasion in response to chemical gradients or through matrix barriers. The assay uses a membrane insert with defined pore size suspended in a multi-well plate: cells are placed in the upper chamber, a chemoattractant is placed in the lower chamber, and cells that successfully migrate through the pores accumulate in the lower chamber, where they can be counted or visualized. Variants that coat the insert with matrix proteins (Matrigel, collagen) enable measurement of invasion capacity. The Transwell assay is a gold-standard method in cell biology for evaluating cell motility, tumor metastatic potential, and the effects of growth factors and inhibitory compounds.