Brazilian Scientists Transform Bioceramic Nanoparticles into High-Precision Tools for Cancer Bioimaging and Targeted Drug Delivery

Brazilian researchers transform hydroxyapatite nanoparticles into luminescent, pH-responsive carriers for targeted cancer drug delivery and bioimaging.

By: AXL Media

Published: Mar 19, 2026, 7:24 AM EDT

Source: Information for this report was sourced from São Paulo Research Foundation (FAPESP)

Engineering Intrinsic Luminescence in Bioceramics

The Nanomedicine and Nanotoxicology Group (GNano) at USP’s São Carlos Institute of Physics has unlocked a sustainable method to utilize hydroxyapatite—a material naturally found in human bones and teeth—for advanced medical imaging. By strategically incorporating carbonate groups into the nanoparticle structure, researchers increased the concentration of crystal defects, which are responsible for the material's internal light emission. This "intrinsic luminescence" eliminates the need for potentially toxic external dyes, providing a safer, low-cost alternative for visualizing how cells interact with nanomaterials.

Precision Bioimaging Through Structural Defects

To ensure the particles remain stable and effective within the human body, the team functionalized the carbonated hydroxyapatite with citrate. This process prevents the particles from clumping in aqueous environments, allowing them to be used as luminescent agents in confocal fluorescence microscopy. Lead researcher Thales Rafael Machado noted that the sample with the highest carbonate content produced the most intense signal, allowing scientists to track the "internalization" of the particles into cells with unprecedented clarity. This breakthrough offers a foundation for new spectroscopic studies of hard tissues and the development of luminescent scaffolds for tissue engineering.

Dual pH Responsive Delivery for Chemotherapy

In a parallel advancement published in ACS Applied Bio Materials, the research group developed a robust strategy to deliver gemcitabine—a standard chemotherapy drug—using these calcium phosphate carriers. The system is engineered to be "dual pH-responsive," meaning the drug remains inactive and stable while circulating in the alkaline environment of the bloodstream. It is only triggered to release its active form upon reaching the more acidic environment characteristic of tumor regions. This localized release significantly increases the drug's bioavailability while protecting healthy tissues from the toxic side effects typical of systemic chemotherapy.