Two-photon fluorescent polydopamine nanodots for CAR-T cell function verification and tumor cell/tissue detection

Area of Science:

• Biomaterials Science
• Nanotechnology
• Cancer Immunotherapy

Background:

• Chimeric antigen receptor T-Cell (CAR-T) immunotherapy shows promise for cancer treatment, necessitating reliable methods for assessing its efficacy.
• Accurate identification of tumor cells and tissues is crucial for diagnosis and surgical guidance.
• Existing cell imaging techniques may interfere with cell behavior, limiting long-term studies.

Purpose of the Study:

• To develop biocompatible, mass-producible polydopamine (PDA) nanodots for advanced biological applications.
• To utilize oxidized PDA (OPDA) nanodots for long-term live cell imaging without affecting cell proliferation.
• To establish OPDA nanodots as a tool for verifying CAR-T cell function and identifying tumor cells based on reactive oxygen species (ROS) levels.

Main Methods:

• Facile synthesis of polydopamine (PDA) nanodots.
• Oxidation of PDA to OPDA nanodots using hydrogen peroxide, yielding materials with one-photon and two-photon fluorescence.
• Utilizing OPDA nanodots for long-term imaging of living cells and assessing CAR-T cell-mediated tumor cell killing.

Main Results:

• OPDA nanodots demonstrated biocompatibility and enabled long-term imaging of living cells without inhibiting mitosis or proliferation.
• CAR-T cell-mediated tumor cell (Raji cells) killing was successfully visualized and quantified using OPDA nanodot fluorescence.
• Differential fluorescence intensity changes, due to varying ROS concentrations, allowed for the distinction between tumor and normal cells.

Conclusions:

• Mass-produced OPDA nanodots are a novel organic material with valuable two-photon fluorescence properties for advanced imaging.
• OPDA nanodots offer a non-inhibitory method for long-term live cell imaging, crucial for studying cellular dynamics.
• This approach provides a versatile platform for CAR-T cell function verification and sensitive tumor cell/tissue detection.