Phenothiazine-Based Nanoaggregates: Dual Role in Bioimaging and Stem Cell-Driven Photodynamic Therapy

Area of Science:

• Nanomedicine
• Biotechnology
• Medical Imaging

Background:

• Photodynamic therapy (PDT) faces challenges in selective photosensitizer delivery and minimizing systemic toxicity.
• Mesenchymal stem cells (MSCs) offer potential as biological carriers due to tumor tropism and low immunogenicity.

Purpose of the Study:

• To evaluate novel aggregation-induced emission (AIE) active phenothiazine derivatives, NPI-PTZ and BTZ-PTZ, as theranostic agents.
• To assess the efficacy of using MSCs (hBM-MSCs and hASCs) to deliver these compounds for combined bioimaging and PDT.

Main Methods:

• Synthesis and characterization of NPI-PTZ and BTZ-PTZ compounds.
• Internalization and stability studies of compounds within hBM-MSCs and hASCs.
• Evaluation of phototoxicity and cytotoxicity of the MSC-compound complexes after light irradiation.

Main Results:

• NPI-PTZ and BTZ-PTZ demonstrated excellent fluorescent probe and photosensitizing capabilities.
• Compounds were efficiently internalized by MSCs, maintaining stable fluorescence for days.
• Irradiation induced phototoxicity, with no significant cytotoxic effects under normal conditions.

Conclusions:

• NPI-PTZ and BTZ-PTZ, when delivered by MSCs, show potential as theranostic tools for integrated bioimaging and PDT.
• This approach offers a promising strategy for advanced clinical applications in targeted therapy and diagnosis.