3.3 DNA-PAINT
The DNA-PAINT technique utilises the transient binding of fluorescently labelled DNA oligonucleotides (“imager”) to their complementary target strands (“docking”) to achieve the blinking effect of SMLM techniques (Schnitzbauer et al., 2017) and obtain a resolution of 10 nm (Figure 2c). DNA-PAINT has been used to determine the amount and distribution of αV integrin accumulation regulated by the purinergic P2Y2 receptor in pancreatic ductal adenocarcinoma (Tomas Bort et al., 2023). A modification of DNA-PAINT, quantitative PAINT (qPAINT), allows accurate molecular counting and was used for the quantitation of the P2Y2 oligomer composition (Joseph et al., 2021). DNA-PAINT limitations include complex probe design, efficient delivery of the imager DNA nucleotides to the docking target, and slow data acquisition rates. However, DNA-PAINT is compatible with other SRN techniques, such as RESI, allowing the achievement of even higher resolution, making it a technique of choice for many applications.