# Gadolinium-Doped Hydroxyapatite Nanoparticles Functionalized with Curcumin and Folic Acid: Structural Insights and Magnetic Behavior for Theranostic Applications

## TL;DR

Researchers developed a new type of nanoparticle with magnetic properties and drug delivery capabilities for potential use in medical imaging and treatment.

## Contribution

A novel theranostic nanoplatform combining Gd-doped hydroxyapatite with curcumin and folic acid for MRI contrast and targeted therapy.

## Key findings

- Gd3+ ions were successfully incorporated into the hydroxyapatite lattice with minimal structural distortion.
- Functionalization with curcumin and folic acid was confirmed through spectroscopic methods.
- NMR relaxation measurements showed MRI contrast performance comparable to commercial agents.

## Abstract

Gadolinium-doped hydroxyapatite nanoparticles (HapGd NPs) have emerged as promising multifunctional platforms for biomedical applications due to their unique combination of biocompatibility, structural tunability, and magnetic responsiveness. In this work, HapGd nanoparticles were synthesized using a microwave-assisted method and subsequently functionalized with curcumin and folic acid to enhance therapeutic efficiency and selective targeting. The synthesized nanostructures were characterized using various techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), and relaxometry. Structural analyses revealed successful incorporation of Gd3+ ions into the Hap lattice, resulting in reduced unit cell volume and slight lattice distortion, while preserving the apatite crystalline framework. Surface functionalization with curcumin and folic acid was confirmed through spectroscopic characterization, demonstrating effective molecular attachment. Nuclear Magnetic Resonance (NMR) relaxation measurements indicated that Gd doping endowed paramagnetic behavior suitable for contrast enhancement in magnetic resonance imaging (MRI). Relaxometry studies revealed a strong linear correlation between 1/T1 and the Gd3+ concentration, especially in the functionalized samples, with performance comparable to the commercial contrast agent Omniscan™. The developed HapGd-based nanoplatform exhibits integrated diagnostic and therapeutic potential, providing a foundation for future research in biomedical applications.