Rhodamine picolyl azide

The EdU incorporation assay measures DNA synthesis by adding the thymidine analog 5-ethynyl-2′-deoxyuridine to cells or tissues, where it is incorporated into newly synthesized DNA during S phase. Incorporated EdU is detected by copper-catalyzed azide-alkyne cycloaddition, in which a fluorescent azide covalently reacts with the ethynyl group on EdU, allowing S-phase cells to be detected by fluorescence microscopy, flow cytometry, or high-content imaging. EdU detection does not require DNA denaturation or anti-BrdU antibody access, which preserves sample structure and improves compatibility with immunostaining and multiparameter cytometry compared with BrdU-based detection. EdU can be cytotoxic in a cell-type- and exposure-dependent manner, so pulse duration, concentration, and continuous-labeling designs should be validated for each cell type.

Bioluminescent and fluorescent imaging xenograft models use tumor cells engineered to express optical reporters so tumor engraftment, growth, dissemination, and treatment response can be monitored longitudinally in living animals and validated ex vivo. Bioluminescence imaging usually measures luciferase activity after substrate administration and is commonly used as a surrogate for viable reporter-expressing tumor burden, while fluorescence imaging measures reporter or probe emission and can support tumor localization, ex vivo confirmation, or complementary multimodal analysis.

Gel electrophoresis is a method for separating biological macromolecules (such as nucleic acids or proteins) by forcing them through a gel matrix under an electric field.

Protein electrophoresis separates proteins in a polyacrylamide gel under an electric field; in SDS-PAGE, sodium dodecyl sulfate denatures proteins and gives them a broadly similar negative charge-to-mass ratio, so migration mainly reflects apparent molecular mass through the gel matrix. The readout is a stained protein band pattern: band position estimates apparent molecular mass using protein standards, band intensity reflects relative protein abundance within the linear range of staining/detection, and changes in band pattern can reflect protein expression, degradation, purification, or sample composition.