Merging sound and light: dual-mode ultrasound/NIR fluorescence imaging with metal-doped graphene quantum dots

The National Institute of Biomedical Imaging and Bioengineering awarded Texas Christian University $495,541 on August 18, 2026, under the Discovery and Applied Research for Technological Innovations to Improve Human Health program (CFDA 93.286) to develop metal-doped graphene quantum dots as dual-mode contrast agents combining ultrasound and near-infrared fluorescence imaging.

The research will synthesize and optimize biocompatible metal-doped graphene quantum dots to overcome limitations of current ultrasound contrast agents and conventional fluorophores, addressing clinical need for lower-cost, portable diagnostic approaches with improved stability and imaging depth. The work progresses through three phases: synthesis and structural optimization of the quantum dots for enhanced ultrasound and fluorescence performance; testing in vascular and tissue phantoms; and in vivo imaging in rats to assess biodistribution, evaluate clinical diagnostic targets, and toxicity. The award is classified as a Project Grant.

Performance occurs in Fort Worth, Texas, with a period of performance from August 18, 2026, through August 17, 2029.

Abstract

Dual-mode imaging is an emerging frontier in biomedical diagnostics offering complementary advantages of detecting and tracing targets inaccessible to single imaging techniques. In this proposal we develop novel dule-mode contrast agents aiming to combine the anatomical visualization of ultrasound imaging (USI) with the high sensitivity of fluorescence imaging. There is a significant clinical need for such combined diagnostic approach: imaging techniques like MRI and CT face cost and accessibility challenges, while ultrasound and fluorescence associate with lower diagnostic costs and greater portability. However, the limitations of current ultrasound contrast agents and conventional visible fluorophores, such as low stability and limited imaging depth, necessitate innovative solutions. This project will develop and validate a novel platform, biocompatible metal-doped graphene quantum dots (mgqds) as a cost-effective dual-mode contrast agent integrating USI contrast enhancement with near-infrared (NIR) fluorescence for deep tissue imaging and molecular diagnostics. Photostable NIR fluorescence intrinsic to mgqds enables deeper tissue imaging than conventional fluorophores while they also possess higher stability than current microbubble ultrasound contrast agents. Preliminary data validates the capability of mgqds to perform both, ultrasound and fluorescence imaging in small animal models. The research will progress through three phases: (1) synthesis and structural optimization of mgqds for enhanced ultrasound and fluorescence performance, (2) testing optimized mgqds for dual-mode imaging in vascular and tissue phantoms (3) in vivo imaging in rats to assess biodistribution, evaluate future clinical diagnostic targets, and toxicity. By overcoming the limitations of current ultrasound contrast agents and fluorophores used in clinic, mgqds have the potential to improve diagnostic accuracy in oncology, cardiovascular disease, and inflammatory disorders. Their simple, scalable and cost- effective synthesis suggests the potential for broad applicability in personalized medicine and limited infrastructure settings. Ultimately, this initiative will bridge current gaps in imaging technology, enhancing healthcare accessibility and advancing global diagnostic capabilities.