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Bio

Bio


With my background in medicine, microdevice engineering, and nanotechnology, my strengths lie in developing novel solutions to urgent problems in medicine and cancer research. Having developed a diagnostic microfluidic device at Caltech and initiated a clinical trial to test the device on glioblastoma patients at UCLA, I?m particlularly interested in moving promising technologies past the proof-of-concept phase and into the clinic. My career goals are to continue to work at the interface of medicine and technology as an academic scientist, engineering new wearable and implantable technologies for earlier cancer detection and continuous monitoring.

Clinical Focus


  • Residency

Honors & Awards


  • Front cover: Science Translational Medicine (28 February), Science Translational Medicine (2018)
  • Poster Award - First Prize, Stanford Bio-X Symposium, Stanford, CA (2017)
  • Oral Presentation Award - Best Talk, SURPAS Postdoc Symposium, Stanford, CA (2016)
  • Poster Award - First Prize, Canary Early Detection Summit, Palo Alto, CA (2016)
  • Poster Award - First Prize, IEEE EMBS MIcro/Nanotechnology in Medicine Conference, Waikoloa, HI (2016)
  • Dean?s Postdoctoral Fellowship, Stanford School of Medicine (2014)
  • The Gerald S. Levey, M.D., Medical Science Scholarship, UCLA (2011)
  • Lemelson-MIT Caltech Invention Prize, Caltech, MIT, and Lemelson Program (2009)
  • Front cover: Nature Biotechnology (16 November), Nature Biotechnology (2008)
  • Caltech Graduate Research Assistantship, Caltech (2006-2010)
  • Letter of Distinction: UCLA GI, Endocrine, and Reproductive Health II Bloc, UCLA (2006)
  • NIH Medical Scientist Training Program, UCLA (2004-2012)
  • NSF Graduate Fellowship Honorable Mention, NSF (2004)
  • Departmental Honors, Stanford Chemistry, Stanford (2002)
  • Advanced Placement Scholar with Distinction, The College Board (1997)
  • Advanced Placement Scholar with Honor, The College Board (1996)

Boards, Advisory Committees, Professional Organizations


  • Vice-President, American Medical Association, UCLA Chapter (2004 - 2005)
  • President, American Medical Association, UCLA Chapter (2005 - 2006)

Patents


  • Ophir Vermesh, Sanjiv Sam Gambhir, Seung-Min Park, Tianjia Jessie Ge, Amin Aalipour. "United States Patent WO2016200900A1 Intravascular Magnetic Wire for Detection, Retrieval or Elimination of Disease Associated Biomarkers and Toxins.", Leland Stanford Junior University, Dec 15, 2016
  • Ophir Vermesh, Brian KH Yen, James R. Heath. "United States Patent US20090053732A1 Microfluidic Devices, Methods and Systems for Detecting Target Molecules.", California Institute of Technology, Feb 26, 2009

Research & Scholarship

Current Research and Scholarly Interests


My interests lie at the interface of medicine and technology, engineering new wearable and implantable technologies for earlier cancer detection and continuous monitoring. I am particularly interested in moving promising diagnostic technologies past the proof-of-concept phase and into the clinic.

Lab Affiliations


Publications

All Publications


  • An intravascular magnetic wire for the high-throughput retrieval of circulating tumour cells in vivo NATURE BIOMEDICAL ENGINEERING Vermesh, O., Aalipour, A., Ge, T., Saenz, Y., Guo, Y., Alam, I. S., Park, S., Adelson, C. N., Mitsutake, Y., Vilches-Moure, J., Godoy, E., Bachmann, M. H., Ooi, C., Lyons, J. K., Mueller, K., Arami, H., Green, A., Solomon, E., Wang, S. X., Gambhir, S. S. 2018; 2 (9): 696?705
  • Intraoperative Molecular Imaging in Lung Cancer: The State of the Art and the Future. Molecular therapy : the journal of the American Society of Gene Therapy Rogalla, S. n., Joosten, S. C., Alam, I. S., Gambhir, S. S., Vermesh, O. n. 2018; 26 (2): 338?41

    View details for PubMedID 29398484

  • Toward achieving precision health. Science translational medicine Gambhir, S. S., Ge, T. J., Vermesh, O. n., Spitler, R. n. 2018; 10 (430)

    Abstract

    Health care systems primarily focus on patients after they present with disease, not before. The emerging field of precision health encourages disease prevention and earlier detection by monitoring health and disease based on an individual's risk. Active participation in health care can be encouraged with continuous health-monitoring devices, providing a higher-resolution picture of human health and disease. However, the development of monitoring technologies must prioritize the collection of actionable data and long-term user engagement.

    View details for PubMedID 29491186

  • The Exosome Total Isolation Chip. ACS nano Liu, F. n., Vermesh, O. n., Mani, V. n., Ge, T. J., Madsen, S. J., Sabour, A. n., Hsu, E. C., Gowrishankar, G. n., Kanada, M. n., Jokerst, J. V., Sierra, R. G., Chang, E. n., Lau, K. n., Sridhar, K. n., Bermudez, A. n., Pitteri, S. J., Stoyanova, T. n., Sinclair, R. n., Nair, V. S., Gambhir, S. S., Demirci, U. n. 2017

    Abstract

    Circulating tumor-derived extracellular vesicles (EVs) have emerged as a promising source for identifying cancer biomarkers for early cancer detection. However, the clinical utility of EVs has thus far been limited by the fact that most EV isolation methods are tedious, nonstandardized, and require bulky instrumentation such as ultracentrifugation (UC). Here, we report a size-based EV isolation tool called ExoTIC (exosome total isolation chip), which is simple, easy-to-use, modular, and facilitates high-yield and high-purity EV isolation from biofluids. ExoTIC achieves an EV yield ?4-1000-fold higher than that with UC, and EV-derived protein and microRNA levels are well-correlated between the two methods. Moreover, we demonstrate that ExoTIC is a modular platform that can sort a heterogeneous population of cancer cell line EVs based on size. Further, we utilize ExoTIC to isolate EVs from cancer patient clinical samples, including plasma, urine, and lavage, demonstrating the device's broad applicability to cancers and other diseases. Finally, the ability of ExoTIC to efficiently isolate EVs from small sample volumes opens up avenues for preclinical studies in small animal tumor models and for point-of-care EV-based clinical testing from fingerprick quantities (10-100 ?L) of blood.

    View details for DOI 10.1021/acsnano.7b04878

    View details for PubMedID 29090896

  • High-Density, Multiplexed Patterning of Cells at Single-Cell Resolution for Tissue Engineering and Other Applications ANGEWANDTE CHEMIE-INTERNATIONAL EDITION Vermesh, U., Vermesh, O., Wang, J., Kwong, G. A., Ma, C., Hwang, K., Heath, J. R. 2011; 50 (32): 7378-7380

    View details for DOI 10.1002/anie.201102249

    View details for Web of Science ID 000293840400033

    View details for PubMedID 21717543

    View details for PubMedCentralID PMC3651859

  • Integrated barcode chips for rapid, multiplexed analysis of proteins in microliter quantities of blood NATURE BIOTECHNOLOGY Fan, R., Vermesh, O., Srivastava, A., Yen, B. K., Qin, L., Ahmad, H., Kwong, G. A., Liu, C., Gould, J., Hood, L., Heath, J. R. 2008; 26 (12): 1373-1378

    Abstract

    As the tissue that contains the largest representation of the human proteome, blood is the most important fluid for clinical diagnostics. However, although changes of plasma protein profiles reflect physiological or pathological conditions associated with many human diseases, only a handful of plasma proteins are routinely used in clinical tests. Reasons for this include the intrinsic complexity of the plasma proteome, the heterogeneity of human diseases and the rapid degradation of proteins in sampled blood. We report an integrated microfluidic system, the integrated blood barcode chip that can sensitively sample a large panel of protein biomarkers over broad concentration ranges and within 10 min of sample collection. It enables on-chip blood separation and rapid measurement of a panel of plasma proteins from quantities of whole blood as small as those obtained by a finger prick. Our device holds potential for inexpensive, noninvasive and informative clinical diagnoses, particularly in point-of-care settings.

    View details for DOI 10.1038/nbt.1507

    View details for Web of Science ID 000261591300023

    View details for PubMedID 19029914

    View details for PubMedCentralID PMC2775523

  • Toward large arrays of multiplex functionalized carbon nanotube sensors for highly sensitive and selective molecular detection NANO LETTERS Pengfei, Q. F., Vermesh, O., Grecu, M., Javey, A., Wang, O., Dai, H. J., Peng, S., Cho, K. J. 2003; 3 (3): 347-351

    View details for DOI 10.1021/nl034010k

    View details for Web of Science ID 000181586600015

  • Hysteresis caused by water molecules in carbon nanotube field-effect transistors NANO LETTERS Kim, W., Javey, A., Vermesh, O., Wang, O., Li, Y. M., DAI, H. J. 2003; 3 (2): 193-198

    View details for DOI 10.1021/nl0259232

    View details for Web of Science ID 000181001500018

  • Real-time point-of-care total protein measurement with a miniaturized optoelectronic biosensor and fast fluorescence-based assay. Biosensors & bioelectronics Mahzabeen, F., Vermesh, O., Levi, J., Tan, M., Alam, I. S., Chan, C. T., Gambhir, S. S., Harris, J. S. 2020: 112823

    Abstract

    Measurement of total protein in urine is key to monitoring kidney health in diabetes. However, most total protein assays are performed using large, expensive laboratory chemistry analyzers that are not amenable to point-of-care analysis or home monitoring and cannot provide real-time readouts. We developed a miniaturized optoelectronic biosensor using a vertical cavity surface-emitting laser (VCSEL), coupled with a fast protein assay based on protein-induced fluorescence enhancement (PIFE), that can dynamically measure protein concentrations in protein-spiked buffer, serum, and urine in seconds with excellent sensitivity (urine LOD?=?0.023?g/L, LOQ?=?0.075?g/L) and over a broad range of physiologically relevant concentrations. Comparison with gold standard clinical assays and standard fluorimetry tools showed that the sensor can accurately and reliably quantitate total protein in clinical urine samples from patients with diabetes. Our VCSEL biosensor is amenable to integration with miniaturized electronics, which could afford a portable, low-cost, easy-to-use device for sensitive, accurate, and real-time total protein measurements from small biofluid volumes.

    View details for DOI 10.1016/j.bios.2020.112823

    View details for PubMedID 33715946

  • Molecular Imaging of Chimeric Antigen Receptor T Cells by ICOS-ImmunoPET. Clinical cancer research : an official journal of the American Association for Cancer Research Simonetta, F., Alam, I. S., Lohmeyer, J. K., Sahaf, B., Good, Z., Chen, W., Xiao, Z., Hirai, T., Scheller, L., Engels, P., Vermesh, O., Robinson, E., Haywood, T., Sathirachinda, A., Baker, J., Malipatlolla, M. B., Schultz, L. M., Spiegel, J. Y., Lee, J. T., Miklos, D. B., Mackall, C. L., Gambhir, S. S., Negrin, R. 2020

    Abstract

    PURPOSE: Immunomonitoring of chimeric antigen receptor (CAR) T cells relies primarily on their quantification in the peripheral blood, which inadequately quantifies their biodistribution and activation status in the tissues. Non-invasive molecular imaging of CAR T cells by positron emission tomography (PET) is a promising approach with the ability to provide spatial, temporal and functional information. Reported strategies rely on the incorporation of reporter transgenes or ex vivo biolabeling, significantly limiting the application of CAR T cell molecular imaging. In the present study, we assessed the ability of antibody-based PET (immunoPET) to non-invasively visualize CAR T cells.EXPERIMENTAL DESIGN: After analyzing human CAR T cells in vitro and ex vivo from patient samples to identify candidate targets for immunoPET, we employed a syngeneic, orthotopic murine tumor model of lymphoma to assess the feasibility of in vivo tracking of CAR T cells by immunoPET using the 89Zr-DFO-anti-ICOS tracer we previously reported.RESULTS: Analysis of human CD19-CAR T cells during activation identified the Inducible T-cell COStimulator (ICOS) as a potential target for immunoPET. In a preclinical tumor model, 89Zr-DFO-ICOS mAb PET-CT imaging detected significantly higher signal in specific bone marrow-containing skeletal sites of CAR T cell treated mice compared with controls. Importantly, administration of ICOS-targeting antibodies at tracer doses did not interfere with CAR T cell persistence and function.CONCLUSIONS: This study highlights the potential of ICOS-immunoPET imaging for monitoring of CAR T cell therapy, a strategy readily applicable to both commercially available and investigational CAR T cells.

    View details for DOI 10.1158/1078-0432.CCR-20-2770

    View details for PubMedID 33087332

  • Visualization of activated T cells by OX40-immunoPET as a strategy for diagnosis of acute Graft-versus-Host-Disease. Cancer research Alam, I. S., Simonetta, F., Scheller, L., Mayer, A. T., Murty, S., Vermesh, O., Nobashi, T. W., Lohmeyer, J. K., Hirai, T., Baker, J., Lau, K. H., Negrin, R., Gambhir, S. S. 2020

    Abstract

    Graft versus host disease (GvHD) is a major complication of allogeneic hematopoietic cell transplantation (HCT), mediated primarily by donor T cells that become activated and attack host tissues. Non-invasive strategies detecting T cell activation would allow for early diagnosis and possibly more effective management of HCT recipients. Positron emission tomography (PET) imaging is a sensitive and clinically relevant modality ideal for GvHD diagnosis and there is a strong rationale for the use of PET tracers that can monitor T cell activation and expansion with high specificity. The tumor necrosis factor (TNF) receptor superfamily member OX40 (CD134) is a cell surface marker that is highly specific for activated T cells, is upregulated during GvHD, and mediates disease pathogenesis. We recently reported the development of an antibody-based activated T cell imaging agent targeting OX40. In the present study, we visualize the dynamics of OX40 expression in a major histocompatibility complex (MHC)-mismatch mouse model of acute GvHD using OX40-immunoPET. This approach enabled visualization of T cell activation at early stages of disease, prior to overt clinical symptoms with high sensitivity and specificity. This study highlights the potential utility of the OX40 PET imaging as a new strategy for GvHD diagnosis and therapy monitoring.

    View details for DOI 10.1158/0008-5472.CAN-20-1149

    View details for PubMedID 32900772

  • Low-frequency ultrasound-mediated cytokine transfection enhances T cell recruitment at local and distant tumor sites. Proceedings of the National Academy of Sciences of the United States of America Ilovitsh, T. n., Feng, Y. n., Foiret, J. n., Kheirolomoom, A. n., Zhang, H. n., Ingham, E. S., Ilovitsh, A. n., Tumbale, S. K., Fite, B. Z., Wu, B. n., Raie, M. N., Zhang, N. n., Kare, A. J., Chavez, M. n., Qi, L. S., Pelled, G. n., Gazit, D. n., Vermesh, O. n., Steinberg, I. n., Gambhir, S. S., Ferrara, K. W. 2020

    Abstract

    Robust cytotoxic T cell infiltration has proven to be difficult to achieve in solid tumors. We set out to develop a flexible protocol to efficiently transfect tumor and stromal cells to produce immune-activating cytokines, and thus enhance T cell infiltration while debulking tumor mass. By combining ultrasound with tumor-targeted microbubbles, membrane pores are created and facilitate a controllable and local transfection. Here, we applied a substantially lower transmission frequency (250 kHz) than applied previously. The resulting microbubble oscillation was significantly enhanced, reaching an effective expansion ratio of 35 for a peak negative pressure of 500 kPa in vitro. Combining low-frequency ultrasound with tumor-targeted microbubbles and a DNA plasmid construct, 20% of tumor cells remained viable, and ?20% of these remaining cells were transfected with a reporter gene both in vitro and in vivo. The majority of cells transfected in vivo were mucin 1+/CD45- tumor cells. Tumor and stromal cells were then transfected with plasmid DNA encoding IFN-?, producing 150 pg/106 cells in vitro, a 150-fold increase compared to no-ultrasound or no-plasmid controls and a 50-fold increase compared to treatment with targeted microbubbles and ultrasound (without IFN-?). This enhancement in secretion exceeds previously reported fourfold to fivefold increases with other in vitro treatments. Combined with intraperitoneal administration of checkpoint inhibition, a single application of IFN-? plasmid transfection reduced tumor growth in vivo and recruited efficacious immune cells at both the local and distant tumor sites.

    View details for DOI 10.1073/pnas.1914906117

    View details for PubMedID 32430322

  • Photoacoustic clinical imaging. Photoacoustics Steinberg, I., Huland, D. M., Vermesh, O., Frostig, H. E., Tummers, W. S., Gambhir, S. S. 2019; 14: 77?98

    Abstract

    Photoacoustic is an emerging biomedical imaging modality, which allows imaging optical absorbers in the tissue by acoustic detectors (light in - sound out). Such a technique has an immense potential for clinical translation since it allows high resolution, sufficient imaging depth, with diverse endogenous and exogenous contrast, and is free from ionizing radiation. In recent years, tremendous developments in both the instrumentation and imaging agents have been achieved. These opened avenues for clinical imaging of various sites allowed applications such as brain functional imaging, breast cancer screening, diagnosis of psoriasis and skin lesions, biopsy and surgery guidance, the guidance of tumor therapies at the reproductive and urological systems, as well as imaging tumor metastases at the sentinel lymph nodes. Here we survey the various clinical and pre-clinical literature and discuss the potential applications and hurdles that still need to be overcome.

    View details for DOI 10.1016/j.pacs.2019.05.001

    View details for PubMedID 31293884

  • Tracking T Cell Activation By OX40 Immuno-PET: A Novel Strategy for Imaging of Graft Versus Host Disease Simonetta, F., Alam, I. S., Mayer, A. T., Murty, S., Vermesh, O., Hirai, T., Nobashi, T., Lau, K., Gambhir, S. S., Negrin, R. S. AMER SOC HEMATOLOGY. 2018
  • Emerging Intraoperative Imaging Modalities to Improve Surgical Precision MOLECULAR IMAGING AND BIOLOGY Alam, I. S., Steinberg, I., Vermesh, O., van den Berg, N. S., Rosenthal, E. L., van Dam, G. M., Ntziachristos, V., Gambhir, S. S., Hernot, S., Rogalla, S. 2018; 20 (5): 705?15
  • Positron emission tomography imaging of activated T cells by targeting OX40 reveals spatiotemporal immune dynamics and predicts response to in situ tumor vaccination Mayer, A. T., Alam, I. S., Sagiv-Barfi, I., Wang, K., Vermesh, O., Czerwinski, D. K., Johnson, E. M., James, M. L., Levy, R., Gambhir, S. S. AMER ASSOC CANCER RESEARCH. 2018
  • PET imaging of OX40+activated T cells predicts therapeutic response in a murine cancer vaccine model Alam, I., Mayer, A., Sagiv-Barfi, I., Vermesh, O., Wang, K., Johnson, E., Czerwinski, D., James, M. L., Levy, R., Gambhir, S. SOC NUCLEAR MEDICINE INC. 2018
  • Imaging activated T cells predicts response to cancer vaccines. The Journal of clinical investigation Alam, I. S., Mayer, A. T., Sagiv-Barfi, I. n., Wang, K. n., Vermesh, O. n., Czerwinski, D. K., Johnson, E. M., James, M. L., Levy, R. n., Gambhir, S. S. 2018

    Abstract

    In situ cancer vaccines are under active clinical investigation, given their reported ability to eradicate both local and disseminated malignancies. Intratumoral vaccine administration is thought to activate a T cell-mediated immune response, which begins in the treated tumor and cascades systemically. In this study, we describe a PET tracer (64Cu-DOTA-AbOX40) that enabled noninvasive and longitudinal imaging of OX40, a cell-surface marker of T cell activation. We report the spatiotemporal dynamics of T cell activation following in situ vaccination with CpG oligodeoxynucleotide in a dual tumor-bearing mouse model. We demonstrate that OX40 imaging was able to predict tumor responses on day 9 after treatment on the basis of tumor tracer uptake on day 2, with greater accuracy than both anatomical and blood-based measurements. These studies provide key insights into global T cell activation following local CpG treatment and indicate that 64Cu-DOTA-AbOX40 is a promising candidate for monitoring clinical cancer immunotherapy strategies.

    View details for PubMedID 29596062

  • Towards clinically translatable in vivo nanodiagnostics Nature Reviews Materials Park, S., Aalipour, A., Vermesh, O., Yu, J., Gambhir, S. S. 2017; 2
  • Molecular profiling of single circulating tumor cells from lung cancer patients PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Park, S., Wong, D. J., Ooi, C. C., Kurtz, D. M., Vermesh, O., Aalipour, A., Suh, S., Pian, K. L., Chabon, J. J., Lee, S. H., Jamali, M., Say, C., Carter, J. N., Lee, L. P., Kuschner, W. G., Schwartz, E. J., Shrager, J. B., Neal, J. W., Wakelee, H. A., Diehn, M., Nair, V. S., Wang, S. X., Gambhir, S. S. 2016; 113 (52): E8379-E8386

    Abstract

    Circulating tumor cells (CTCs) are established cancer biomarkers for the "liquid biopsy" of tumors. Molecular analysis of single CTCs, which recapitulate primary and metastatic tumor biology, remains challenging because current platforms have limited throughput, are expensive, and are not easily translatable to the clinic. Here, we report a massively parallel, multigene-profiling nanoplatform to compartmentalize and analyze hundreds of single CTCs. After high-efficiency magnetic collection of CTC from blood, a single-cell nanowell array performs CTC mutation profiling using modular gene panels. Using this approach, we demonstrated multigene expression profiling of individual CTCs from non-small-cell lung cancer (NSCLC) patients with remarkable sensitivity. Thus, we report a high-throughput, multiplexed strategy for single-cell mutation profiling of individual lung cancer CTCs toward minimally invasive cancer therapy prediction and disease monitoring.

    View details for DOI 10.1073/pnas.1608461113

    View details for PubMedID 27956614

  • Targeted superparamagnetic iron oxide nanoparticles for early detection of cancer: Possibilities and challenges. Nanomedicine : nanotechnology, biology, and medicine Bakhtiary, Z., Saei, A. A., Hajipour, M. J., Raoufi, M., Vermesh, O., Mahmoudi, M. 2016; 12 (2): 287-307

    Abstract

    Nanomedicine, the integration of nanotechnological tools in medicine demonstrated promising potential to revolutionize the diagnosis and treatment of various human health conditions. Nanoparticles (NPs) have shown much promise in diagnostics of cancer, especially since they can accommodate targeting molecules on their surface, which search for specific tumor cell receptors upon injection into the blood stream. This concentrates the NPs in the desired tumor location. Furthermore, such receptor-specific targeting may be exploited for detection of potential metastases in an early stage. Some NPs, such as superparamagnetic iron oxide NPs (SPIONs), are also compatible with magnetic resonance imaging (MRI), which makes their clinical translation and application rather easy and accessible for tumor imaging purposes. Furthermore, multifunctional and/or theranostic NPs can be used for simultaneous imaging of cancer and drug delivery. In this review article, we will specifically focus on the application of SPIONs in early detection and imaging of major cancer types.Super-paramagnetic iron oxide nanoparticles (SPIONs) have been reported by many to be useful as an MRI contrast agent in the detection of tumors. To further enhance the tumor imaging, SPIONs can be coupled with tumor targeting motifs. In this article, the authors performed a comprehensive review on the current status of using targeted SPIONS in tumor detection and also the potential hurdles to overcome.

    View details for DOI 10.1016/j.nano.2015.10.019

    View details for PubMedID 26707817

  • Gene expression profiling of individual circulating tumor cells from non-small cell lung cancer (NSCLC) patients via integrated nanotechnologies Park, S., Wong, D. J., Ooi, C., Nair, V. S., Vermesh, O., Lee, S., Suh, S., Lee, L. P., Wang, S. X., Gambhir, S. S. AMER ASSOC CANCER RESEARCH. 2015
  • Sol-Gel Synthesis and Electrospraying of Biodegradable (P2O5)(55)-(CaO)(30)-(Na2O)(15) Glass Nanospheres as a Transient Contrast Agent for Ultrasound Stem Cell Imaging ACS NANO Foroutan, F., Jokerst, J. V., Gambhir, S. S., Vermesh, O., Kim, H., Knowles, J. C. 2015; 9 (2): 1868-1877

    Abstract

    Ultrasound imaging is a powerful tool in medicine because of the millisecond temporal resolution and submillimeter spatial resolution of acoustic imaging. However, the current generation of acoustic contrast agents is primarily limited to vascular targets due to their large size. Nanosize particles have the potential to be used as a contrast agent for ultrasound molecular imaging. Silica-based nanoparticles have shown promise here; however, their slow degradation rate may limit their applications as a contrast agent. Phosphate-based glasses are an attractive alternative with controllable degradation rate and easily metabolized degradation components in the body. In this study, biodegradable P2O5-CaO-Na2O phosphate-based glass nanospheres (PGNs) were synthesized and characterized as contrast agents for ultrasound imaging. The structure of the PGNs was characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), (31)P magic angle spinning nuclear magnetic resonance ((31)P MAS NMR), and Fourier transform infrared (FTIR) spectroscopy. The SEM images indicated a spherical shape with a diameter size range of 200-500 nm. The XRD, (31)P NMR, and FTIR results revealed the amorphous and glassy nature of PGNs that consisted of mainly Q(1) and Q(2) phosphate units. We used this contrast to label mesenchymal stem cells and determined in vitro and in vivo detection limits of 5 and 9 ?g/mL, respectively. Cell counts down to 4000 could be measured with ultrasound imaging with no cytoxicity at doses needed for imaging. Importantly, ion-release studies confirmed these PGNs biodegrade into aqueous media with degradation products that can be easily metabolized in the body.

    View details for DOI 10.1021/nn506789y

    View details for PubMedID 25625373

  • A self-powered, one-step chip for rapid, quantitative and multiplexed detection of proteins from pinpricks of whole blood LAB ON A CHIP Wang, J., Ahmad, H., Ma, C., Shi, Q., Vermesh, O., Vermesh, U., Heath, J. 2010; 10 (22): 3157-3162

    Abstract

    We describe an automated, self-powered chip based on lateral flow immunoassay for rapid, quantitative, and multiplex protein detection from pinpricks of whole blood. The device incorporates on-chip purification of blood plasma by employing inertial forces to focus blood cells away from the assay surface, where plasma proteins are captured and detected on antibody "barcode" arrays. Power is supplied from the capillary action of a piece of adsorbent paper, and sequentially drives, over a 40 minute period, the four steps required to capture serum proteins and then develop a multiplex immunoassay. An 11 protein panel is assayed from whole blood, with high sensitivity and high reproducibility. This inexpensive, self-contained, and easy to operate chip provides a useful platform for point-of-care diagnoses, particularly in resource-limited settings.

    View details for DOI 10.1039/c0lc00132e

    View details for Web of Science ID 000283600900017

    View details for PubMedID 20924527

    View details for PubMedCentralID PMC3651856

  • Fast Nonlinear Ion Transport via Field-induced Hydrodynamic Slip in Sub-20-nm Hydrophilic Nanofluidic Transistors NANO LETTERS Vermesh, U., Choi, J. W., Vermesh, O., Fan, R., Nagarah, J., Heath, J. R. 2009; 9 (4): 1315-1319

    Abstract

    Electrolyte transport through an array of 20 nm wide, 20 microm long SiO(2) nanofluidic transistors is described. At sufficiently low ionic strength, the Debye screening length exceeds the channel width, and ion transport is limited by the negatively charged channel surfaces. At source-drain biases >5 V, the current exhibits a sharp, nonlinear increase, with a 20-50-fold conductance enhancement. This behavior is attributed to a breakdown of the zero-slip condition. Implications for energy conversion devices are discussed.

    View details for DOI 10.1021/nl802931r

    View details for Web of Science ID 000265030000006

    View details for PubMedID 19265427

  • Self-powered microfluidic chips for multiplexed protein assays from whole blood LAB ON A CHIP Qin, L., Vermesh, O., Shi, Q., Heath, J. R. 2009; 9 (14): 2016-2020

    Abstract

    We report herein on a self-powered, self-contained microfluidic-based chip designed to separate plasma from whole blood, and then execute an assay of a multiplexed panel of plasma biomarker proteins. The power source is based upon a chemical reaction that is catalytically triggered by the push of a button on the chip. We demonstrate assays of a dozen blood-based protein biomarkers using this automated, self-contained device. This platform can potentially permit high throughput, accurate, multiplexed blood diagnostic measurements in remote locations and by minimally trained individuals.

    View details for DOI 10.1039/b821247c

    View details for Web of Science ID 000267572000008

    View details for PubMedID 19568669

    View details for PubMedCentralID PMC3651861

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