Honors & Awards

  • Travel Award, World Molecular Imaging Society (2019)
  • Travel Award, World Molecular Imaging Society (2018)
  • Travel Award, World Molecular Imaging Society (2017)
  • Dean’s Postdoctoral Fellowship, Stanford University School of Medicine (2014)
  • Chinese Government Award for Outstanding Self-Financed Students Abroad, China Scholarship Council (2013)
  • Honored Graduate Award, Jilin University (2009)

Education & Certifications

  • Ph.D, Nanyang Technological University, Bioengineering (2014)
  • B.S., Jilin University, Biotechnology (2009)


  • MOZART: A New Technology for Imaging Tumor Heterogeneity In Vivo, Stanford University School of Medicine


    Stanford, CA, United States

Service, Volunteer and Community Work

  • Guest Editor, Special issue of Molecules ""25th Anniversary of Molecules—Recent Advances in Nanochemistry" (2/7/2020 - Present)



  • Conference Session Chair, World Molecular Imaging Congress (9/4/2019 - 9/7/2019)



Professional Affiliations and Activities

  • Council member, Stanford University Postdoctoral Association (SURPAS) (2014 - Present)
  • Board member, Association of Chinese Students and Scholars at Stanford (ACSSS) (2014 - Present)
  • UN coordinator, Intern Board of World Health Organization (2013 - 2014)
  • Founder and Chairperson, NTU Graduate Toastmasters Association (2013 - 2014)
  • Founder and President, Nanyang Scholars Toastmasters Club (2013 - 2014)
  • Secretary-General, Student Council of Jilin University School of Life Sciences (2006 - 2007)
  • Deputy Secretary-General, Student Council of Jilin University School of Life Sciences (2005 - 2006)

All Publications

  • Optical Microscopy and Coherence Tomography of Cancer in Living Subjects. Trends in cancer Si, P., Honkala, A., de la Zerda, A., Smith, B. R. 2020; 6 (3): 205–22


    Intravital microscopy (IVM) and optical coherency tomography (OCT) are two powerful optical imaging tools that allow visualization of dynamic biological activities in living subjects with subcellular resolutions. Recent advances in labeling and label-free techniques empower IVM and OCT for a wide range of preclinical and clinical cancer imaging, providing profound insights into the complex physiological, cellular, and molecular behaviors of tumors. Preclinical IVM and OCT have elucidated many otherwise inscrutable aspects of cancer biology, while clinical applications of IVM and OCT are revolutionizing cancer diagnosis and therapies. We review important progress in the fields of IVM and OCT for cancer imaging in living subjects, highlighting key technological developments and their emerging applications in fundamental cancer biology research and clinical oncology investigation.

    View details for DOI 10.1016/j.trecan.2020.01.008

    View details for PubMedID 32101724

  • Gold Nanobipyramids as Second Near Infrared Optical Coherence Tomography Contrast Agents for in Vivo Multiplexing Studies. Nano letters Si, P., Shevidi, S., Yuan, E., Yuan, K., Lautman, Z., Jeffrey, S. S., Sledge, G. W., de la Zerda, A. 2019


    Developing contrast-enhanced optical coherence tomography (OCT) techniques is important for specific imaging of tissue lesions, molecular imaging, cell-tracking, and highly sensitive microangiography and lymphangiography. Multiplexed OCT imaging in the second near-infrared (NIR-II) window is highly desirable since it allows simultaneous imaging and tracking of multiple biological events in high resolution with deeper tissue penetration in vivo. Here we demonstrate that gold nanobipyramids can function as OCT multiplexing contrast agents, allowing high-resolution imaging of two separate lymphatic flows occurring simultaneously from different drainage basins into the same lymph node in a live mouse. Contrast-enhanced multiplexed lymphangiography of a melanoma tumor in vivo shows that the peritumoral lymph flow upstream of the tumor is unidirectional, and tumor is accessible to such flow. Whereas the lymphatic drainage coming out from the tumor is multidirectional. We also demonstrate real-time tracking of the contrast agents draining from a melanoma tumor specifically to the sentinel lymph node of the tumor and the three-dimensional distribution of the contrast agents in the lymph node.

    View details for DOI 10.1021/acs.nanolett.9b03344

    View details for PubMedID 31585502

  • Gold Nanoprisms as Optical Coherence Tomography Contrast Agents in the Second Near-Infrared Window for Enhanced Angiography in Live Animals ACS NANO Si, P., Yuan, E., Liba, O., Winetraub, Y., Yousefi, S., SoRelle, E., Yecies, D., Dutta, R., de la Zerda, A. 2018; 12 (12): 11986–94


    Optical coherence tomography angiography (OCTA) is an important tool for investigating vascular networks and microcirculation in living tissue. Traditional OCTA detects blood vessels via intravascular dynamic scattering signals derived from the movements of red blood cells (RBCs). However, the low hematocrit and long latency between RBCs in capillaries make these OCTA signals discontinuous, leading to incomplete mapping of the vascular networks. OCTA imaging of microvascular circulation is particularly challenging in tumors due to the abnormally slow blood flow in angiogenic tumor vessels and strong attenuation of light by tumor tissue. Here, we demonstrate in vivo that gold nanoprisms (GNPRs) can be used as OCT contrast agents working in the second near-infrared window, significantly enhancing the dynamic scattering signals in microvessels and improving the sensitivity of OCTA in skin tissue and melanoma tumors in live mice. With GNPRs as contrast agents, the postinjection OCT angiograms showed 41 and 59% more microvasculature than preinjection angiograms in healthy mouse skin and melanoma tumors, respectively. By enabling better characterization of microvascular circulation in vivo, GNPR-enhanced OCTA could lead to better understanding of vascular functions during pathological conditions, more accurate measurements of therapeutic response, and improved patient prognoses.

    View details for DOI 10.1021/acsnano.8b03862

    View details for Web of Science ID 000454567500025

    View details for PubMedID 30422624

  • Optical Coherence Tomography of Lymphatic Vessel Endothelial Hyaluronan Receptors In Vivo Si, P., Sen, D., Duttal, R., Yousefi, S., Dalal, R., Winetraub, Y., Liba, O., de la Zerda, A., Izatt, J. A., Fujimoto, J. G., Tuchin, V. V. SPIE-INT SOC OPTICAL ENGINEERING. 2018

    View details for DOI 10.1117/12.2282890

    View details for Web of Science ID 000453776500007

  • Macroscopic Assembly of Gold Nanorods into Superstructures with Controllable Orientations by Anisotropic Affinity Interaction LANGMUIR Rong, Y., Song, L., Si, P., Zhang, L., Lu, X., Zhang, J., Nie, Z., Huang, Y., Chen, T. 2017; 33 (48): 13867–73
  • In Vivo Molecular Optical Coherence Tomography of Lymphatic Vessel Endothelial Hyaluronan Receptors SCIENTIFIC REPORTS Si, P., Sen, D., Dutta, R., Yousefi, S., Dalal, R., Winetraub, Y., Liba, O., de la Zerda, A. 2017; 7


    Optical Coherence Tomography (OCT) imaging of living subjects offers increased depth of penetration while maintaining high spatial resolution when compared to other optical microscopy techniques. However, since most protein biomarkers do not exhibit inherent contrast detectable by OCT, exogenous contrast agents must be employed for imaging specific cellular biomarkers of interest. While a number of OCT contrast agents have been previously studied, demonstrations of molecular targeting with such agents in live animals have been historically challenging and notably limited in success. Here we demonstrate for the first time that microbeads (µBs) can be used as contrast agents to target cellular biomarkers in lymphatic vessels and can be detected by OCT using a phase variance algorithm. This molecular OCT method enables in vivo imaging of the expression profiles of lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1), a biomarker that plays crucial roles in inflammation and tumor metastasis. In vivo OCT imaging of LVYE-1 showed that the biomarker was significantly down-regulated during inflammation induced by acute contact hypersensitivity (CHS). Our work demonstrated a powerful molecular imaging tool that can be used for high resolution studies of lymphatic function and dynamics in models of inflammation, tumor development, and other lymphatic diseases.

    View details for DOI 10.1038/s41598-017-01172-x

    View details for Web of Science ID 000400048500002

    View details for PubMedID 28439123

  • Gold Nanoparticle-Graphite-Like C3N4 Nanosheet Nanohybrids Used for Electrochemiluminescent Immunosensor ANALYTICAL CHEMISTRY Chen, L., Zeng, X., Si, P., Chen, Y., Chi, Y., Kim, D., Chen, G. 2014; 86 (9): 4188-4195


    Two-dimensional graphite-like carbon nitride nanosheets (g-C3N4 NSs) were hybridized with gold nanoparticles (Au NPs) to construct an electrochemiluminescence (ECL) immunosensor. The prepared Au NP-functionalized g-C3N4 NS nanohybrids (Au-g-C3N4 NHs) exhibit strong and stable cathodic ECL activity compared to g-C3N4 NSs due to the important roles of Au NPs in trapping and storing the electrons from the conduction band of g-C3N4 NSs, as well as preventing high energy electron-induced passivation of g-C3N4 NSs. On the basis of the improved ECL stability and ECL peak intensity of the Au-g-C3N4 NHs, a novel ECL immunosensor was developed to detect carcinoembryonic antigen (CEA) as a model target analyte. The ECL immunosensor has a sensitive response to CEA in a linear range of 0.02-80 ng mL(-1) with a detection limit of 6.8 pg mL(-1). Additionally, the proposed immunosensor shows high specificity, good reproducibility, and long-term stability.

    View details for DOI 10.1021/ac403635f

    View details for Web of Science ID 000335719900020

    View details for PubMedID 24707951

  • Fluorescent pH Sensor Based on Ag@SiO2 Core-Shell Nanoparticle ACS APPLIED MATERIALS & INTERFACES Bai, Z., Chen, R., Si, P., Huang, Y., Sun, H., Kim, D. 2013; 5 (12): 5856-5860


    We have demonstrated a novel method for the preparation of a fluorescence-based pH sensor by combining the plasmon resonance band of Ag core and pH sensitive dye (HPTS). A thickness-variable silica shell is placed between Ag core and HPTS dye to achieve the maximum fluorescence enhancement. At the shell thickness of 8 nm, the fluorescence intensity increases 4 and 9 times when the sensor is excited at 405 and 455 nm, respectively. At the same time, the fluorescence intensity shows a good sensitivity toward pH value in the range of 5-9, and the ratio of emission intensity at 513 nm excited at 455 nm to that excited at 405 nm versus the pH value in the range of 5-9 is determined. It is believed that the present pH sensor has the potential for determining pH real time in the biological sample.

    View details for DOI 10.1021/am401528w

    View details for Web of Science ID 000321237000062

    View details for PubMedID 23716502

  • A hierarchically structured composite of Mn3O4/3D graphene foam for flexible nonenzymatic biosensors JOURNAL OF MATERIALS CHEMISTRY B Si, P., Dong, X., Chen, P., Kim, D. 2013; 1 (1): 110-115

    View details for DOI 10.1039/c2tb00073c

    View details for Web of Science ID 000314784900012

  • Electrodeposition of hierarchical MnO2 spheres for enzyme immobilization and glucose biosensing JOURNAL OF MATERIALS CHEMISTRY B Si, P., Chen, P., Kim, D. 2013; 1 (21): 2696-2700

    View details for DOI 10.1039/c3tb20341g

    View details for Web of Science ID 000318568600002

  • Nanomaterials for electrochemical non-enzymatic glucose biosensors RSC ADVANCES Si, P., Huang, Y., Wang, T., Ma, J. 2013; 3 (11): 3487-3502

    View details for DOI 10.1039/c2ra22360k

    View details for Web of Science ID 000314973800002

  • Hierarchically Structured One-Dimensional TiO2 for Protein Immobilization, Direct Electrochemistry, and Mediator-Free Glucose Sensing ACS NANO Si, P., Ding, S., Yuan, J., Lou, X. W., Kim, D. 2011; 5 (9): 7617-7626


    A novel one-dimensional hierarchically structured TiO(2) (1DHS TiO(2)) was synthesized by a solvothermal method using multiwalled carbon nanotubes (MWCNTs) as a template and evaluated for the immobilization of protein and biosensing applications. Characterization studies showed that the 1DHS TiO(2) possessed an anatase crystalline structure and a large surface area with narrow pore size distribution. Fast direct electron transfer was observed for glucose oxidase (GOx) immobilized on the 1DHS TiO(2), and excellent electrocatalytic performance for glucose detection can be obtained without a mediator. The glucose sensor based on the GOx/1DHS TiO(2)-modified electrode had a high sensitivity of 9.90 μA mM(-1) cm(-2) and a low detection limit of 1.29 μM. The fabricated biosensor displayed good selectivity and long-term stability, indicating that the novel structured TiO(2) is a promising material for the immobilization of biomolecules and the fabrication of third-generation biosensors.

    View details for DOI 10.1021/nn202714c

    View details for Web of Science ID 000295187400098

    View details for PubMedID 21866956

  • Highly stable and sensitive glucose biosensor based on covalently assembled high density Au nanostructures BIOSENSORS & BIOELECTRONICS Si, P., Kannan, P., Guo, L., Son, H., Kim, D. 2011; 26 (9): 3845-3851
  • An electrochemically formed three-dimensional structure of polypyrrole/graphene nanoplatelets for high-performance supercapacitors RSC ADVANCES Si, P., Ding, S., Lou, X. (., Kim, D. 2011; 1 (7): 1271-1278

    View details for DOI 10.1039/c1ra00519g

    View details for Web of Science ID 000296388800018

  • Selective and sensitive determination of dopamine by composites of polypyrrole and graphene modified electrodes ANALYST Si, P., Chen, H., Kannan, P., Kim, D. 2011; 136 (24): 5134-5138


    A novel method is developed to fabricate the polypyrrole (PPy) and graphene thin films on electrodes by electrochemical polymerization of pyrrole with graphene oxide (GO) as a dopant, followed by electrochemical reduction of GO in the composite film. The composite of PPy and electrochemically reduced graphene oxide (eRGO)-modified electrode is highly sensitive and selective toward the detection of dopamine (DA) in the presence of high concentrations of ascorbic acid (AA) and uric acid (UA). The sensing performance of the PPy/eRGO-modified electrode is investigated by differential pulse voltammetry (DPV), revealing a linear range of 0.1-150 μM with a detection limit of 23 nM (S/N = 3). The practical application of the PPy/eRGO-modified electrode is successfully demonstrated for DA determination in human blood serum.

    View details for DOI 10.1039/c1an15772h

    View details for Web of Science ID 000297223000005

    View details for PubMedID 22010122