About

Professor Qifa Zhou, PhD, is a Research Professor at the NIH Resource on Medical Ultrasonic Transducer Technology and holds appointments in the Departments of Biomedical Engineering and Ophthalmology at the University of Southern California (USC). He received his Ph.D. in Electronic Engineering from Xi’an Jiaotong University and completed postdoctoral work at the Materials Research Institute at Pennsylvania State University before joining USC in 2002. His research focuses on the development of high frequency ultrasound composite and piezoelectric thick film ultrasound transducers and arrays fabricated using MEMS technology for biomedical imaging applications. He has developed high sensitivity PMN-PT single crystal transducers for ultrasound and photoacoustic imaging of the retina and intravascular ultrasound (IVUS) applications. More recently, he and his collaborators have been working on novel imaging tools to assess the elastic properties of the retina using phase-resolved optical coherence tomography (OCT) combined with acoustic radiation force (ARF), as well as investigating the use of ultrasound for retinal stimulation. Professor Zhou is recognized as a Fellow of SPIE and AIMBE, a senior member of the IEEE Ultrasonics, Ferroelectrics, and Frequency Control (UFFC) Society, and an active member of several technical committees within IEEE and SPIE. He serves as an Associate Editor of IEEE UFFC and has held leadership roles such as Chapter Chair in IEEE UFFC since 2015. His contributions to the field have been acknowledged through awards including the best student paper competition at the 2010 IEEE International Ultrasonics Symposium and the best poster paper at the 2015 SPIE Photonics West. He has published over 170 journal papers in the areas of ultrasound transducer technology and biomedical imaging.

Research topics

• Computer Science
• Materials science
• Electrical engineering
• Nanotechnology
• Physics
• Mechanical engineering
• Artificial Intelligence
• Engineering
• Medicine
• Composite material
• Optics
• Optoelectronics
• Engineering physics
• Telecommunications
• Thermodynamics
• Computer vision
• Embedded system
• Pathology
• Biomedical engineering

Selected publications

• Venous endothelial remodeling mediated by MARCKS promotes angiogenesis and tumor progression in hepatocellular carcinoma: insights from single-cell RNA sequencing

  Frontiers in Immunology · 2026-03-12

  articleOpen accessSenior author

  Background Hepatocellular carcinoma (HCC) is characterized by pronounced heterogeneity and extensive angiogenesis. However, anti-angiogenic therapies often show limited clinical benefit due to therapeutic resistance. Understanding endothelial cell heterogeneity and identifying key regulators of tumor angiogenesis are therefore essential for improving treatment strategies. Methods We integrated multiple single-cell RNA sequencing (scRNA-seq) datasets to systematically characterize endothelial cell heterogeneity in the HCC microenvironment. Based on genes enriched in venous endothelial cells, we developed a prognostic risk model termed the Vein Endothelial-related Risk Scores (VERS). The functional role of the key gene MARCKS was further evaluated using in vitro assays and in vivo xenograft models. Results Venous endothelial cells (VenECs) were identified as key initiators of tumor angiogenesis in HCC. Among the VERS genes, MARCKS emerges as a robust predictor of poor clinical outcome. Functional assays reveal that MARCKS knockdown impairs endothelial cell proliferation, migration and invasion, and attenuates the pro-tumorigenic effects of endothelial-conditioned media. In vivo , MARCKS silencing significantly suppresses tumor growth and vascularization. Discussion Our findings reveal a critical role for venous endothelial cells in HCC angiogenesis and identify MARCKS as a potential therapeutic target, providing molecular insights for precision oncology in HCC.

  PublisherDOI

• Requirements for Human Cerebral Organoids

  Cell Proliferation · 2026-03-31

  articleOpen accessCorresponding

  The data that support the findings of this study are available from the corresponding author upon reasonable request. Data S1: cpr70201-sup-0001-Supinfo.docx. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

  PublisherDOI

• Rapid cancer diagnosis using deep learning–powered label-free subcellular-resolution photoacoustic histology

  Science Advances · 2025-11-21 · 2 citations

  articleOpen access

  Traditional hematoxylin and eosin staining in formalin-fixed paraffin-embedded sections, while essential for diagnostic pathology, is time-consuming, labor intensive, and prone to artifacts that can obscure critical histological details. Label-free ultraviolet photoacoustic microscopy (UV-PAM) has emerged as a promising alternative, offering fast histology-like images without the need for traditional staining and excessive tissue preparation. However, current UV-PAM systems face challenges in achieving the high spatial resolution required for detailed histological analysis and diagnosis. To address this, we developed a subcellular-resolution UV-PAM (SRUV-PAM) system with a 240-nanometer resolution, enabled by the integration of a high numerical aperture (NA) objective lens (NA = 0.64) and the precise piezo actuators for fine scanning control. This configuration allows visualization of detailed nuclear structures. In addition, we demonstrated virtual staining of SRUV-PAM images via cycle-consistent generative adversarial networks and diagnosis of malignant and benign tumors in liver tissues via densely connected convolutional networks DenseNet-121, achieving an area under the receiver operating characteristic curve of 0.902.

  PublisherDOI

• Input-output efficiency evaluation of regional water-energy-food nexus under relational network and uncertainty

  Applied Energy · 2025-05-10 · 4 citations

  article
  PublisherDOI

• Multifocal Optical-Resolution Photoacoustic Microscopy With a Masked Single-Element Transducer

  IEEE Transactions on Medical Imaging · 2025-12-12

  articleOpen access

  Optical-resolution photoacoustic microscopy (OR-PAM) can visualize cellular-level wavelength-dependent optical absorption with high resolution and sensitivity. However, the imaging speed of OR-PAM has been limited by the laser repetition rate due to the point-by-point scanning of a focused laser beam. To overcome this limitation, we propose multifocal optical-resolution photoacoustic microscopy (MOR-PAM) with a single-element ultrasonic transducer, leveraging the diffractive optical element (DOE) and a custom-designed encoding acoustic mask. The DOE generates 8 focal spots of $3~\mu $ m diameter. The acoustic mask was designed to encode photoacoustic signals from different focal spots. MOR-PAM achieved an 8-fold increase in imaging speed compared to conventional OR-PAM with the same laser repetition rate. We demonstrated the MOR-PAM using a 266 nm laser at 10 KHz, providing solutions for rapid OR-PAM beyond the laser repetition rate in a cost-effective way. The proposed method can be applied to versatile OR-PAM configurations and enable new applications where high-speed imaging is critical.

  PublisherOA PDFDOI

• High frequency ultrasound 2D array design and fabrication with 3D printed interposers at 200 μm pitch

  Ultrasonics · 2025-05-02 · 4 citations

  articleSenior authorCorresponding
  PublisherDOI

• Size and Structural Control of Mechanoluminescent ZnS:Mn²⁺ Nanocrystals for Optogenetic Neuromodulation

  ACS Nano · 2025-05-13 · 18 citations

  article

  Mechanoluminescent materials hold immense potential for various transformative applications, from medical imaging and diagnostics to health monitoring and wearable displays. Conventionally produced as bulk powders or microparticles, they face significant size limitations for advanced applications, particularly in biological systems and microscale devices. This work presents an approach to ZnS:Mn2+ nanocrystal synthesis that involves self-assembly and subsequent calcination. In addition to effective size control within the nanoscale, this approach promotes the formation of abundant stacking faults, significantly enhancing piezoelectric and mechanoluminescent properties by increasing trap density and reducing trap depth. Unlike mechanoluminescent materials produced using conventional methods, these nanocrystals demonstrate strong mechanoluminescence without requiring UV pre-excitation, and the light emission persists even after mechanical stress is removed. These advantageous properties make them promising candidates for optogenetic neuromodulation, as they can effectively trigger electrical signals in neurons upon ultrasound stimulation both with and without UV pre-excitation. The persistent mechanoluminescence prolongs the duration of neuronal electrical activity, providing an extended temporal window for neuromodulation compared to conventional mechanoluminescent materials. This study provides a scalable method for producing efficient mechanoluminescent nanoparticles and reveals the crucial role of particle size and defect structures in determining their mechanoluminescent behavior.

  PublisherDOI

• Multiscale analysis of equatorial sclera anisotropy: Revealing discrepancies in fiber orientation and mechanical properties

  Science Advances · 2025-07-09 · 1 citations

  articleOpen accessSenior authorCorresponding

  The sclera, the eye's primary load-bearing tissue, substantially influences the globe's response to intraocular pressure. Although the mechanical properties of the anterior and posterior segments have been extensively studied, the equatorial sclera's properties remain underexplored, limiting our understanding of ocular conditions like myopia, ocular trauma, and glaucoma. Traditional studies that rely solely on fiber orientation to explain scleral mechanics may overlook the tissue's complex biomechanical behavior. To address this gap, we conducted a comprehensive investigation using ultrasonic elastography, optical coherence elastography, and polarizing light microscopy to analyze the equatorial sclera's anisotropic properties. Our findings reveal a counterintuitive result: Mechanical anisotropy in the equatorial sclera contradicts preferred fiber orientation. This integrated approach not only challenges prevailing models of scleral biomechanics but also provides fundamental insights into the mechanisms underlying key ocular conditions, highlighting the importance of multimodal and multiscale analyses in biological tissue research.

  PublisherDOI

• Thrombolysis transducer with wedged matching for IVUS clot detection

  2025-09-15

  article

  Deep vein thrombosis (DVT) affects over 300,000 patients annually in the United States and remains difficult to treat due to the compact structure of retracted thrombi and limitations of current therapies, which carry risks of inefficiency, bleeding, and pulmonary embolism. Ultrasound-enhanced thrombolysis has emerged as a promising strategy, particularly with cavitation agents such as nanodroplets that achieve deeper penetration and higher lysis rates than microbubbles. However, existing intravascular devices often lack combined therapeutic and imaging capabilities, and sub-MHz designs require high activation pressures that hinder clinical translation. Thus, we present a miniaturized intravascular ultrasound system that integrates a low-frequency (750 kHz) therapeutic transducer with a high-frequency (40 MHz) inclined imaging transducer. Rotational B-mode imaging was achieved for thrombolysis with an imaging distance of 4 mm. This unique wedge-matched design enables precise local energy delivery, rotational and forward-looking imaging, and real-time monitoring of thrombolysis, which offers a safer, more effective platform for imaging guided intravascular sonothrombolysis of retracted clots.

  PublisherDOI

• Acoustic Transparency Enabling Functional Ultrasound Imaging Through Mouse and Human Skulls

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-08-28 · 2 citations

  preprintOpen access

  Abstract Ultrasound is one of the most widely used non-invasive imaging modalities for internal organs, yet its application to the brain has been hindered for decades by the skull’s acoustic barrier. This same barrier has kept functional ultrasound imaging (fUSI)—an emerging technology capable of capturing brain-wide neural activity in real time at sub-100 μm resolution—from reaching its transformative potential in neuroscience and clinical medicine. Here, we present an acoustic transparency strategy by modulating skull acoustic properties, to render the brain visible to ultrasound. A brief topical application of an FDA-approved chelating agent matches the skull’s acoustic impedance and sound speed to those of soft tissue, enabling nearly complete ultrasound transmission (94.0 ± 4.4%) with minimal energy loss or distortion. Leveraging this discovery, we developed an acoustic-transparent fUSI platform that maps brain activation across the full brain depth at ∼20 μm spatial resolution without skull removal. This method enables safe, longitudinal brain imaging, is fully reversible, and is demonstrated to be applicable to the ex vivo human skull. This conceptually distinct paradigm—controlling acoustic wave propagation via acoustic property modulation—offers a practical and generalizable solution to one of the most persistent obstacles in transcranial ultrasound imaging, opening the door to broader clinical and research application of ultrasound neuroimaging.

  PublisherOA PDFDOI

Recent grants

• High-Resolution Flow Imaging of Optic Nerve Head and Retrolaminar Microvascular Circulation

  NIH · $2.0M · 2023–2027

• Large aperture and wideband modular ultrasound arrays for the diagnosis of liver cancer

  NIH · $3.3M · 2017–2023

• Center Core Grant for Vision Research

  NIH · $10.3M · 2018–2028

• Phase resolved ARF optical coherence elastography for intravascular imaging

  NIH · $5.6M · 2014–2026

• Non-invasive Ultrasound Stimulated Retinal Prosthesis

  NIH · $2.0M · 2019–2025

Frequent coauthors

• K. Kirk Shung

  381 shared

• Mark S. Humayun

  Southern California Eye Institute

  221 shared

• Zhongping Chen

  175 shared

• Laiming Jiang

  Sichuan University

  167 shared

• Ruimin Chen

  University of Bristol

  166 shared

• Gengxi Lu

  University of Southern California

  163 shared

• Runze Li

  University of Southern California

  120 shared

• Xuejun Qian

  ShanghaiTech University

  119 shared

Education

• Ph.D., Biomedical Engineering

  University of Southern California

  2006

• M.S., Biomedical Engineering

  University of Southern California

  2003

• B.S., Biomedical Engineering

  University of Southern California

  2001

Awards & honors

• 2023 Best Paper Award at the International Conference on the…
• 2023 IAAM Fellow (International Association of Advanced Mate…
• 2022 USC Viterbi Senior Research Award
• 2022 BME Frontier Best Paper
• 2019 National Academy of Inventors Senior Member