Single-molecule analysis of fluorescent carbon dots towards localization-based super-resolution microscopy

Area of Science:

• Nanomaterials Science
• Biophotonics
• Super-resolution Microscopy

Background:

• High-resolution bioimaging relies on advanced fluorescent probes.
• Carbon nanodots (CDs) offer superior optical properties, non-toxicity, and facile synthesis.
• Single-molecule super-resolution imaging using CDs remains underexplored.

Purpose of the Study:

• To characterize the single-molecule fluorescence of three distinct carbon nanodots.
• To compare their performance against a standard fluorescent probe for super-resolution applications.
• To investigate the electron transfer mechanism governing their photophysical behavior.

Main Methods:

• Systematic single-molecule fluorescence characterization of carbon nanodots.
• Comparison with a conventional fluorescent probe.
• Investigation of electron transfer mechanisms using ensemble and single-molecule experiments.
• Measurement of on-off blinking dynamics and photon budget under varying laser power.

Main Results:

• Carbon nanodots exhibited long-lived dark states upon interaction with an electron acceptor.
• The electron transfer mechanism was elucidated through complementary experimental approaches.
• Key parameters for super-resolution microscopy, including photon budget and on-off rates, were quantified.
• A localization precision of approximately 35 nm was achieved using these carbon nanodots.

Conclusions:

• Fluorescent carbon nanodots possess suitable photophysical properties for single-molecule localization super-resolution microscopy.
• Their characterized performance indicates significant potential as alternatives to traditional fluorescent probes.
• Further development of carbon nanodots could advance high-resolution bioimaging techniques.