Quantum dot-based fluorescent probes for targeted imaging of the EJ human bladder urothelial cancer cell line.

QDs are a type of inorganic nanoparticle with unique optical properties. As a fluorescent label, QDs are widely used in biomedical fields. In the present study, fluorescent probes of quantum dots (QDs) conjugated with a prostate stem cell antigen (PSCA) monoclonal antibody (QD-PSCA) were prepared to study the targeted imaging of QD-PSCA probes in EJ human bladder urothelial cancer cells and analyze the feasibility of QD-based non-invasive tumor-targeted imaging in vivo. QDs with an emission wavelength of 605 nm (QD605) were conjugated with PSCA to prepare QD605-PSCA fluorescent probes by chemical covalent coupling. The optical properties of the probes coupled and uncoupled with PSCA were measured and assessed using an ultraviolet spectrophotometer and a fluorescence spectrophotometer. Direct immune-fluorescent labeling was utilized to detect and analyze imaging of the probes for EJ cells. The results revealed that QD605-PSCA probes retained the fluorescent properties of QD605 and the immunogenicity of the PSCA protein. The probes were able to specifically recognize the PSCA protein expressed in bladder cancer cells, while fluorescence was stable and had a long duration. The present study suggests that QD-PSCA fluorescent probes may be useful for specific targeted labeling and imaging in bladder urothelial cancer cells. Furthermore, the probes possess good optical stability and may be useful for research into non-invasive targeted imaging, early diagnosis and targeted in vivo tumor therapy.