Multifunctional yolk-in-shell nanoparticles for pH-triggered drug release and imaging

Area of Science:

• Nanotechnology
• Materials Science
• Biomedical Engineering

Background:

• Multifunctional nanoparticles are crucial for targeted drug delivery and advanced medical imaging.
• Developing nanocarriers with combined therapeutic and diagnostic functions (theranostics) is a key research area.
• Existing nanoplatforms often lack the integration of multiple imaging modalities and controlled release mechanisms.

Purpose of the Study:

• To synthesize novel multifunctional nanoparticles for pH-triggered drug release.
• To achieve multimodal imaging using radioluminescence, upconversion luminescence, and magnetic resonance imaging (MRI).
• To create a yolk-in-shell nanostructure capable of encapsulating chemotherapeutic drugs and enabling controlled release.

Main Methods:

• Synthesis of yolk-in-shell nanoparticles via controlled encapsulation of a radioluminescent nanophosphor yolk within silica, followed by partial etching and coating with an upconverting luminescent shell.
• Loading of metoxantrone chemotherapy drug into the hollow core through shell pores.
• Coating nanoparticles with pH-responsive polyelectrolyte layers (hyaluronic acid sodium salt and chitosan) to control drug release.
• Characterization of luminescence properties under X-ray, blue light, and near-infrared light.
• Evaluation of MRI contrast agent performance (T1 and T2 relaxivity).

Main Results:

• Successfully synthesized yolk-in-shell nanoparticles with distinct layers for drug loading and imaging.
• Demonstrated bright luminescence under various excitation sources (X-ray, 480 nm, 980 nm).
• Achieved effective T1 and T2 magnetic resonance imaging contrast with relaxivities of 3.5 mM⁻¹s⁻¹ (r1) and 64 mM⁻¹s⁻¹ (r2).
• Showcased pH-responsive drug release capabilities mediated by polyelectrolyte coatings.

Conclusions:

• The developed multifunctional nanoparticles are promising for integrated therapeutic and diagnostic applications.
• The yolk-in-shell architecture provides a versatile platform for drug encapsulation and controlled release.
• The combination of multiple imaging modalities (radioluminescence, upconversion luminescence, MRI) enhances diagnostic potential.
• These nanocapsules represent a significant advancement in theranostic nanomedicine.