[Based on in vivo fluorescence imaging technology, to extablish a fluorescence modification method for amphipathic...

Area of Science:

• Polymer Chemistry
• Materials Science
• Biomedical Engineering

Background:

• Amphipathic block polymers are crucial for drug delivery systems.
• Fluorescent labeling allows for in vivo tracking and imaging of these polymers.
• Developing efficient and reliable labeling methods is essential for advancing polymer-based therapeutics.

Purpose of the Study:

• To synthesize Rhodamine B-labeled amphipathic block polymers.
• To evaluate the effect of fluorescent labeling on polymer properties, specifically micellization behavior.
• To demonstrate the utility of the labeled polymers for in vivo tracking using fluorescence imaging.

Main Methods:

• Activation of Rhodamine B with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride.
• Ester exchange reaction to label hydroxyethyl methacrylate (HEMA) with Rhodamine B.
• Polymerization of Rh B-HEMA with other monomers to create labeled amphipathic block polymers.
• Characterization using FT-IR spectra and fluorospectrophotometry.
• Preparation of vinpocetine (VP)-loaded polymeric micelles via solvent evaporation.
• In vivo tissue distribution and whole-body fluorescence imaging.

Main Results:

• Successful synthesis of Rhodamine B-labeled amphipathic block polymers (β-CD-[P(AA-(HEMA-RhB)-MMA)-b-PVP](4)).
• Labeling yield of 4.13% achieved.
• Critical micelle concentration (CMC) of labeled (4.96×10⁻³ mg·L⁻¹) and unlabeled (5.09×10⁻³ mg·L⁻¹) polymers showed no significant difference, indicating preserved micellization behavior.
• VP-loaded micelles exhibited similar in vivo tissue distribution and whole-body fluorescence imaging results compared to unlabeled counterparts.
• Established a fluorescence method for modification of amphipathic block polymers.

Conclusions:

• Rhodamine B successfully modified amphipathic block polymers without altering their micellization behavior.
• The fluorescence labeling method is effective for in vivo tracking and imaging of polymeric micelles.
• This technique provides a valuable tool for studying the biodistribution of drug delivery systems.