# Gram‐Scale Synthesis of Hafnium‐Rich Carbon Dots for Preclinical Computed Tomography Imaging Across Various Systems

## TL;DR

Researchers developed a scalable method to produce hafnium-rich carbon dots that show strong potential for advanced CT imaging in preclinical studies.

## Contribution

A scalable air-assisted pyrolysis method for producing high-Hf-content carbon dots with excellent imaging performance.

## Key findings

- Hf-rCDs have a high Hf content (40.7%) and can be produced in batches exceeding 2 g.
- In vivo CT imaging shows excellent contrast enhancement in multiple physiological systems, including in swine cervical vasculature.
- Hf-rCDs exhibit rapid renal clearance and favorable biosafety, making them suitable for preclinical studies.

## Abstract

Hafnium (Hf) has emerged as a promising element for next‐generation computed tomography (CT) contrast agents owing to its high X‐ray attenuation coefficient and favorable biocompatibility. However, scalable synthesis of Hf‐based imaging probes with sufficiently high metal content for large‐animal preclinical studies remains challenging. Here, we report a facile air‐assisted pyrolysis strategy for the gram‐scale synthesis of Hf‐rich carbon dots (Hf‐rCDs). The resulting Hf‐rCDs exhibit a high Hf content (40.7%), robust batch productivity (>2 g per batch), ultra‐small hydrodynamic size (∼3.2 nm), excellent aqueous solubility (up to 600 mg mL−
1; 244 mg Hf mL−
1), and superior X‐ray attenuation performance. Importantly, Hf‐rCDs demonstrate rapid renal clearance within 2 h post‐injection, supporting a favorable biosafety profile. In vivo CT imaging reveals outstanding contrast enhancement across multiple physiological systems, including the circulatory, urinary, gastrointestinal, and lymphatic systems. Notably, Hf‐rCDs enable high‐resolution visualization of cervical vasculature in swine, highlighting their strong translational potential. Collectively, these results establish Hf‐rCDs as a compelling alternative to conventional iodine‐based contrast agents for advanced CT imaging.

Hafnium (Hf)‐rich carbon dots (Hf‐rCDs) with high metal content (40.7%) and robust batch production capacity (>2 g per batch) are synthesized via a facile air‐assisted pyrolysis method. In vivo CT imaging demonstrates outstanding performance of Hf‐rCDs across multiple physiological systems and enables high‐resolution visualization of swine cervical vasculature, underscoring their strong potential for clinical translation.