A microtiter plate, also called a microplate or microwell plate, is a flat plastic plate containing an array of small wells that function as miniature test tubes. It allows simultaneous processing and analysis of many samples in parallel.
Structure and Laboratory Applications
Microtiter plates are standardized to fit automated instruments and often follow Society for Biomolecular Screening specifications. Common formats include 6, 24, 48, 96, 384 and 1536 wells, with a 96‑well plate being the most widely used. Wells may have flat, round or V‑shaped bottoms and hold volumes ranging from tens to hundreds of microlitres. Plates are typically made from polystyrene for optical assays or polypropylene for chemical resistance and can be treated for cell attachment or left untreated for suspension cultures. Clear, opaque and transparent‑bottom variants allow absorbance, luminescence and fluorescence measurements in microplate readers. Microtiter plates enable high‑throughput experimentation by allowing researchers to perform serial dilutions, enzyme assays, immunoassays such as enzyme‑linked immunosorbent assays (ELISAs), cell proliferation assays and qPCR in a compact format. Standardized external dimensions permit robotic handling, incubation and detection using automated liquid handlers and plate readers.
Examples and Importance
Microtiter plates underpin many routine laboratory workflows. Broth microdilution assays to determine the minimum inhibitory concentration of antibiotics use 96‑ or 384‑well plates to test multiple drug concentrations against bacterial isolates. Clinical diagnostic kits use coated microplates to capture antigens or antibodies in ELISA tests for hormones, viral proteins and antibodies against pathogens. High‑throughput screening in pharmaceutical research relies on 384‑ and 1536‑well plates to evaluate the activity and toxicity of compound libraries. Cell‑based assays measuring cytokine production, cell viability or reporter gene expression are performed in specially treated plates that support cell adhesion. Quantitative PCR instruments use 96‑well and 384‑well plates with thin walls to ensure uniform thermal cycling. The ability to process dozens or hundreds of reactions simultaneously has made microtiter plates indispensable for modern biomedical research and diagnostics.
Microtiter plates provide a standardized, efficient platform for handling small volumes of liquids in parallel. Their adaptability to different assays and compatibility with automated systems have transformed laboratory workflows and enabled high‑throughput experimentation.
Related Terms: ELISA, Microplate reader, 96‑well plate, High‑throughput screening, Broth microdilution