Stepwise pH/reduction-responsive polymeric conjugates for enhanced drug delivery to tumor

Area of Science:

• Biomaterials Science
• Nanotechnology
• Oncology

Background:

• Developing effective drug delivery systems is crucial for cancer therapy.
• Targeted delivery and controlled release can improve treatment efficacy and reduce side effects.

Purpose of the Study:

• To create a charge-conversional polymer carrier for enhanced cancer drug delivery.
• To investigate the pH- and reduction-triggered release of doxorubicin (Dox) from novel micelles.
• To evaluate the in vitro and in vivo performance of the drug delivery system.

Main Methods:

• Synthesis of poly-l-lysine-lipoic acid (PLL-LA) modified with dimethylmaleic anhydride (DA).
• Preparation and characterization of doxorubicin-loaded DA-PLL-LA micelles (Dox-micelles).
• In vitro studies on charge reversal, drug release kinetics, cell internalization, and cytotoxicity.
• In vivo studies in tumor-bearing mice, assessing tumor penetration, targeting, efficacy, and toxicity.

Main Results:

• DA-PLL-LA micelles exhibited pH-dependent charge reversal, enhancing cellular uptake at tumor extracellular pH.
• Dox-micelles showed sustained release under physiological conditions and triggered release in response to pH and glutathione.
• Enhanced in vitro cytotoxicity against A549 cells and excellent tumor penetration in spheroids and slices.
• In vivo studies demonstrated effective tumor targeting, significant antitumor efficacy, and low systemic toxicity in mice.

Conclusions:

• The charge-conversional DA-PLL-LA micelles represent a promising platform for targeted and efficient doxorubicin delivery in cancer treatment.
• The system's ability to respond to tumor microenvironment triggers (pH and reduction) enhances drug release and therapeutic outcomes.
• Further development of this nanocarrier could lead to improved cancer therapies with reduced side effects.