Research Themes

Photoacoustic Imaging

Photoacoustic Imaging (PAI) is an emerging bio-imaging modality that combines optical and acoustic technologies to provide high optical contrast and high resolution in deep tissue. The principle of PAI involves directing pulsed laser light onto tissues, where endogenous or exogenous chromophores—such as hemoglobin, melanin, or molecular agents—absorb specific wavelengths, causing localized thermal expansion and generating PA waves. These PA waves are detected by an ultrasound transducer. PA signals then undergo image reconstruction processing, ultimately producing a PA image that visualizes the optical absorption contrast within the tissue.

PAI has remarkable advantages in imaging depth, resolution, and molecular contrast, making it applicable across various biomedical fields. PAI enables label-free vascular imaging by visualizing blood vessels and tissue oxygenation without external contrast agents. Through oxygen saturation imaging, it provides functional insights into hemoglobin levels, aiding in the assessment of cancer, cardiovascular, and neurovascular health. With targeted contrast agents, PAI also facilitates molecular-specific imaging for precise visualization of cellular markers, supporting early disease detection and therapy monitoring. With its broad applicability, PAI shows promise as a valuable tool for advancing both animal and clinical research

Ultrasound Transducer

Ultrasound transducers (UTs) is a core device in ultrasound technology, responsible for both transmitting and receiving acoustic waves that penetrate tissues non-invasively and safely. UTs can be tailored across a range of frequencies, from low to high frequencies, to suit different imaging needs. Additionally, they come in various types each optimized for specific clinical and research applications based on depth and resolution requirements. These transducers are essential not only in ultrasound imaging but also in photoacoustic sensor and ultrasound stimulation, supporting both diagnostic and therapeutic purposes. Their versatility makes them invaluable across biomedical applications, from fetal and vascular imaging to tissue stimulation and therapeutic interventions.

Multimodal imaging integrates multiple imaging techniques into a single system, allowing comprehensive visualization of structural, functional, and molecular details within biological tissues. This approach is crucial for precise diagnostics, as it leverages the unique strengths of each modality to provide a complete view of complex biological environments.

Utilizing a Transparent Ultrasound Transducer (TUT), we implemented four complementary imaging modalities—Photoacoustic Imaging (PAI), Optical Coherence Tomography (OCT), Fluorescence Imaging (FLI), and Ultrasound Imaging (USI)—in a unified system. This fusion enables high-resolution imaging across optical and acoustic domains and is particularly promising for applications in detecting ocular diseases and monitoring tumors. The multimodal system has significant potential across various pre- and clinical fields, offering detailed insights that single modalities cannot achieve alone.

Ultrasound stimulation encompasses two main approaches: High-Intensity Focused Ultrasound (HIFU) and Low-Intensity Pulsed Ultrasound (LIPUS).  HIFU is a non-invasive therapeutic technology that uses focused ultrasound waves to create both thermal and mechanical effects in targeted tissues. By adjusting parameters, HIFU can raise tissue temperature to induce necrosis or keep it moderate to improve the effectiveness of chemotherapy and radiotherapy, enhancing localized drug delivery. Additionally, HIFU can disrupt tissues mechanically via acoustic cavitation, which facilitates tissue breakdown, known as histotripsy. This versatile technology is applied in cancer, infectious disease, and neurological treatments, expanding therapeutic possibilities in both human and veterinary medicine.

LIPUS is based on a non-thermal mechanism, using low-intensity pulsed ultrasound to produce mechanical vibrations that stimulate cellular processes without significant heat generation. These non-thermal effects activate mechanotransduction pathways, promoting cellular proliferation, differentiation, and repair. LIPUS has versatile applications in bone healing by enhancing osteogenesis, soft tissue repair by supporting tendon and cartilage regeneration, and neuromodulation by safely influencing neuronal activity. 

Wearable biomedical devices enable real-time health monitoring, aiding in early detection and personalized care. In particular, wearable ultrasound devices are a significant advancement, offering non-invasive imaging directly on the skin, which makes continuous and long-term monitoring possible. These devices are used for applications such as cardiovascular assessment, organ function tracking, and at-home cancer screening. Compact and adaptable, wearable ultrasound technology has the potential to expand healthcare access by providing consistent, reliable diagnostics outside traditional clinical settings. In addition, wearable ultrasound devices are expected to support remote diagnostics and AI-driven data classification, enabling faster, more accurate health insights and reducing the need for in-person clinical visits. This technology could facilitate proactive, accessible healthcare through AI-based early detection and personalized treatment recommendations​