Member, Maternal & Child Health Research Institute (MCHRI)
Bachelor of Science, Hong Kong Baptist University - Ho Sin Hang Campus (2010)
Doctor of Philosophy, University of Michigan Ann Arbor (2017)
Master of Science, University of Michigan Ann Arbor (2012)
Tumour-specific fluorescence-guided surgery for pancreatic cancer using panitumumab-IRDye800CW: a phase 1 single-centre, open-label, single-arm, dose-escalation study.
The lancet. Gastroenterology & hepatology
BACKGROUND: Complete surgical resection remains the primary curative option for pancreatic ductal adenocarcinoma, with positive margins in 30-70% of patients. In this study, we aimed to evaluate the use of intraoperative tumour-specific imaging to enhance a surgeon's ability to detect visually occult cancer in real time.METHODS: In this single-centre, open-label, single-arm study, done in the USA, we enrolled patients who had clinically suspicious or biopsy-confirmed pancreatic ductal adenocarcinomas and were scheduled for curative surgery. Eligible patients were 19 years of age or older with a life expectancy of more than 12 weeks and a Karnofsky performance status of at least 70% or an Eastern Cooperative Oncology Group or Zubrod level of one or lower, who were scheduled to undergo curative surgery. Patients were sequentially enrolled into each dosing group and 2-5 days before surgery, patients were intravenously infused with 100 mg of unlabelled panitumumab followed by 25 mg, 50 mg, or 75 mg of the near-infrared fluorescently labelled antibody (panitumumab-IRDye800CW). The primary endpoint was to determine the optimal dose of panitumumab-IRDye800CW in identifying pancreatic ductal adenocarcinomas as measured by tumour-to-background ratio in all patients. The tumour-to-background ratio was defined as the fluorescence signal of the tumour divided by the fluorescence signal of the surrounding healthy tissue. The dose-finding part of this study has been completed. This study is registered with ClinicalTrials.gov, NCT03384238.FINDINGS: Between April, 2018, and July, 2019, 16 patients were screened for enrolment onto the study. Of the 16 screened patients, two (12%) patients withdrew from the study and three (19%) were not eligible; 11 (69%) patients completed the trial, all of whom were clinically diagnosed with pancreatic ductal adenocarcinoma. The mean tumour-to-background ratio of primary tumours was 3·0 (SD 0·5) in the 25 mg group, 4·0 (SD 0·6) in the 50 mg group, and 3·7 (SD 0·4) in the 75 mg group; the optimal dose was identified as 50 mg. Intraoperatively, near-infrared fluorescence imaging provided enhanced visualisation of the primary tumours, metastatic lymph nodes, and small (<2 mm) peritoneal metastasis. Intravenous administration of panitumumab-IRDye800CW at the doses of 25 mg, 50 mg, and 75 mg did not result in any grade 3 or higher adverse events. There were no serious adverse events attributed to panitumumab-IRDye800CW, although four possibly related adverse events (grade 1 and 2) were reported in four patients.INTERPRETATION: To our knowledge, this study presents the first clinical use of panitumumab-IRDye800CW for detecting pancreatic ductal adenocarcinomas and shows that panitumumab-IRDye800CW is safe and feasible to use during pancreatic cancer surgery. Tumour-specific intraoperative imaging might have added value for treatment of patients with pancreatic ductal adenocarcinomas through improved patient selection and enhanced visualisation of surgical margins, metastatic lymph nodes, and distant metastasis.FUNDING: National Institutes of Health and the Netherlands Organization for Scientific Research.
View details for DOI 10.1016/S2468-1253(20)30088-1
View details for PubMedID 32416764
- Optimal Dosing Strategy for Fluorescence-Guided Surgery with Panitumumab-IRDye800CW in Head and Neck Cancer MOLECULAR IMAGING AND BIOLOGY 2020; 22 (1): 156–64
Predicting Therapeutic Antibody Delivery into Human Head and Neck Cancers.
Clinical cancer research : an official journal of the American Association for Cancer Research
PURPOSE: The efficacy of antibody-based therapeutics depends on successful drug delivery into solid tumors, therefore there is a clinical need to measure intratumoral antibody distribution. This study aims to develop and validate an imaging and computation platform to directly quantify and predict antibody delivery into human head and neck cancers in a clinical study.EXPERIMENTAL DESIGN: Twenty-four patients received systemic infusion of a near-infrared (NIR) fluorescence-labeled therapeutic antibody followed by surgical tumor resection. A computational platform was developed to quantify the extent of heterogeneity of intratumoral antibody distribution. Both univariate and multivariate regression analysis were used to select the most predictive tumor biological factors for antibody delivery. Quantitative image features from the pre-treatment magnetic resonance imaging (MRI) were extracted and correlated with fluorescence imaging of antibody delivery.RESULTS: This study not only confirmed heterogeneous intratumoral antibody distribution in line with many preclinical reports, but also quantified the extent of inter-patient, inter-tumor, and intra-tumor heterogeneity of antibody delivery. This study demonstrated the strong predictive value of tumor size for intratumoral antibody accumulation and its significant impact on antibody distribution in both primary tumor and lymph node metastasis. Furthermore, this study established the feasibility of using contrast-enhanced MRI to predict antibody delivery.CONCLUSIONS: This study provides a clinically translatable platform to measure antibody delivery into solid tumors and yields valuable insight into clinically relevant antibody tumor penetration, with implications in the selection of patients amenable to antibody therapy and the design of more effective dosing strategies.
View details for DOI 10.1158/1078-0432.CCR-19-3717
View details for PubMedID 31980465
Safety and Stability of Antibody-Dye Conjugate in Optical Molecular Imaging.
Molecular imaging and biology
The development of molecularly targeted tracers is likely to improve the accuracy of diagnostic, screening, and therapeutic tools. Despite the many therapeutic antibodies that are FDA-approved with known toxicity, only a limited number of antibody-dye conjugates have been introduced to the clinic. Thorough evaluation of the safety, stability, and pharmacokinetics of antibody conjugates in the clinical setting compared with their parental components could accelerate the clinical approval of antibodies as agents for molecular imaging. Here we investigate the safety and stability of a near-infrared fluorescent dye (IRDye800CW) conjugated panitumumab, an approved therapeutic antibody, and report on the product stability, pharmacokinetics, adverse events, and QTc interval changes in patients.Panitumumab-IRDye800CW was made under good manufacturing practice (GMP) conditions in a single batch on March 26, 2014, and then evaluated over 4.5 years at 0, 3, and 6 months, and then at 6-month intervals thereafter. We conducted early phase trials in head and neck, lung, pancreas, and brain cancers with panitumumab-IRDye800CW. Eighty-one patients scheduled to undergo standard-of-care surgery were infused with doses between 0.06 to 2.83 mg/kg of antibody. Patient ECGs, blood samples, and adverse events were collected over 30-day post-infusion for analysis.Eighty-one patients underwent infusion of the study drug at a range of doses. Six patients (7.4 %) experienced an adverse event that was considered potentially related to the drug. The most common event was a prolonged QTc interval which occurred in three patients (3.7 %). Panitumumab-IRDye800CW had two OOS results at 42 and 54 months while meeting all other stability testing criteria.Panitumumab-IRDye800CW was safe and stable to administer over a 54-month window with a low rate of adverse events (7.4 %) which is consistent with the rate associated with panitumumab alone. This data supports re-purposing therapeutic antibodies as diagnostic imaging agents with limited preclinical toxicology studies.
View details for DOI 10.1007/s11307-020-01536-2
View details for PubMedID 32880818
Endoscopic Fluorescence-Guided Surgery for Sinonasal Cancer Using an Antibody-Dye Conjugate.
OBJECTIVE: Endoscopic resection of sinonasal squamous cell carcinoma has become the standard of care, but challenges remain in obtaining clear resection margins. The current study evaluated the feasibility of endoscopic fluorescence-guided surgery (FGS) to improve surgical resection in a human sinus surgical model.METHODS: A fluorescence endoscope optimized for near-infrared (NIR) fluorescence detection was evaluated in a phantom study. Various endoscope diameters (4 and 10mm) and viewing angles (0, 30, and 45 degrees) were evaluated to determine the sensitivity of the system for IRDye800CW detection at various working distances (1-5 cm). Endoscopic FGS was then validated in a three-dimensional human sinus surgical model to which squamous cell tumors derived from mice were inserted. Mice had received intravenous panitumumab-IRDye800CW and upon fluorescence-guided tumor resection, mean fluorescence intensity (MFI) and tumor-to-background ratio (TBR) were calculated in in situ and ex vivo settings.RESULTS: A significantly higher fluorescence intensity was found when using the 10-mm diameter endoscope compared to the 4mm diameter endoscope (P<.001). No significant difference in MFI was found among the viewing angles of the 4-mm diameter endoscope. Using the human sinus model, the highest MFI and TBR were obtained at a 1-cm working distance compared to longer working distances.CONCLUSION: We demonstrate that clinically acceptable TBRs were obtained with several working distances to discriminate tumor tissue from adjacent normal tissue in a human sinus model, and that endoscopic FGS may have great potential in identifying residual tumor tissue regions during surgery. Laryngoscope, 2019.
View details for DOI 10.1002/lary.28483
View details for PubMedID 31854462
Probe-based fluorescence dosimetry of an antibody-dye conjugate to identify head and neck cancer as a first step to fluorescence-guided tissue preselection for pathological assessment.
Head & neck
BACKGROUND: Despite the rapid growth of fluorescence imaging, accurate sampling of tissue sections remains challenging. Development of novel technologies to improve intraoperative assessment of tissue is needed.METHODS: A novel contact probe-based fluorescence dosimeter device, optimized for IRDye800CW quantification, was developed. After evaluation of the device in a phantom setup, its clinical value was defined ex vivo in patients with head and neck squamous cell carcinoma who received panitumumab-IRDye800CW.RESULTS: Ten patients were enrolled with a total of 216 data points obtained. Final histopathology showed tumor in 119 spots and normal tissue in 97 spots. Fluorescence-to-excitation ratios in tumor tissue were more than three times higher than those in normal tissue. The area under the curve was 0.86 (95% CI: 0.81-0.91) for tumor detection.CONCLUSIONS: Fluorescence-guided tissue preselection using a fluorescence dosimeter could have substantial impact on tissue sampling for frozen section analysis and potentially reduce sampling errors.
View details for DOI 10.1002/hed.25964
View details for PubMedID 31571335
- The Clinical Application of Fluorescence-Guided Surgery in Head and Neck Cancer JOURNAL OF NUCLEAR MEDICINE 2019; 60 (6): 758–63
Optimal Dosing Strategy for Fluorescence-Guided Surgery with Panitumumab-IRDye800CW in Head and Neck Cancer.
Molecular imaging and biology : MIB : the official publication of the Academy of Molecular Imaging
PURPOSE: To identify the optimal dosing strategy for fluorescence-guided surgery in patients with head and neck squamous cell carcinoma, we conducted a dose-ranging study evaluating the anti-epidermal growth factor receptor (EGFR) therapeutic antibody, panitumumab, that was fluorescently labeled with the near-infrared dye IRDye800CW.PROCEDURES: Patients (n=24) received either 0.5 or 1.0mg/kg panitumumab-IRDye800CW in the weight-based dosing group or 25 or 50mg panitumumab-IRDye800CW in the fixed dosing group. Following surgery, whole primary specimens were imaged in a closed-field device and the mean fluorescence intensity (MFI) and tumor-to-background ratio (TBR) were assessed. Clinical variables, including dose, time of infusion-to-surgery, age, unlabeled dose, gender, primary tumor site, and tumor size, were analyzed to evaluate the factors affecting the fluorescence intensity in order to identify the optimal dose for intraoperative fluorescence imaging.RESULTS: A total of 24 primary tumor specimens were imaged and analyzed in this study. Although no correlations between TBR and dose of panitumumab-IRDye800CW were found, there were moderate-strong correlations between the primary tumor MFI and panitumumab-IRDye800CW dose for fixed dose (mg) (R2=0.42) and for dose/weight (mg/kg) (R2=0.54). Results indicated that the optimal MFI was at approximately 50mg for fixed dose and 0.75mg/kg for dose/weight. No significant differences were found for the primary tumor MFI and TBRs between the weight-based dosing and the fixed dosing groups. MFIs significantly increased when the infusion-to-surgery window was reduced to within 2days (vs. 3days or more, p<0.05).CONCLUSIONS: Antibody-based imaging for surgical resection is under investigation in multiple clinical trials. Our data suggests that a fixed dose of 50mg is an appropriate diagnostic dose for successful surgical fluorescence imaging.
View details for PubMedID 31054001
The Clinical Application of Fluorescence-Guided Surgery in Head and Neck Cancer.
Journal of nuclear medicine : official publication, Society of Nuclear Medicine
Although surgical resection has been the primary treatment modality of solid tumors for decades, surgeons still rely on visual cues and palpation to delineate healthy from cancerous tissue. This may contribute to the high rate (up to 30%) of positive margins in head and neck cancer resections. Margin status in these patients is the most important prognostic factor for overall survival. In addition, second primary lesions may be present at the time of surgery. Although often unnoticed by the medical team, these lesions can have significant survival ramifications. We hypothesize that real-time fluorescence imaging can enhance intraoperative decision-making by aiding the surgeon in detecting close or positive margins and visualizing unanticipated regions of primary disease. The purpose of this study was to assess the clinical utility of real-time fluorescence imaging for intraoperative decision-making. Methods: Head and neck cancer patients (n = 14) scheduled for curative resection were enrolled in a clinical trial evaluating panitumumab-IRDye800CW for surgical guidance (NCT02415881). Open-field fluorescence imaging was performed throughout the surgical procedure. The fluorescence signal was quantified as signal-to-background ratios to characterize the fluorescence contrast of regions of interest relative to background. Results: Fluorescence imaging was able to improve surgical decision-making in three cases (21.4%); identification of a close margin (n = 1) and unanticipated regions of primary disease (n = 2). Conclusion: This study demonstrates the clinical applications of fluorescence imaging on intraoperative decision-making. This information is required for designing phase III clinical trials using this technique. Furthermore, this study is the first to demonstrate this application for intraoperative decision-making during resection of primary tumors.
View details for PubMedID 30733319
- Rapid, non-invasive fluorescence margin assessment: Optical specimen mapping in oral squamous cell carcinoma ORAL ONCOLOGY 2019; 88: 58–65
Rapid, non-invasive fluorescence margin assessment: Optical specimen mapping in oral squamous cell carcinoma.
2019; 88: 58–65
OBJECTIVE: Surgical resection remains the primary treatment for the majority of solid tumors. Despite efforts to obtain wide margins, close or positive surgical margins (<5 mm) are found in 15-30% of head and neck cancer patients. Obtaining negative margins requires immediate, intraoperative feedback of margin status. To this end, we propose optical specimen mapping of resected tumor specimens immediately after removal.MATERIALS AND METHODS: A first-in-human pilot study was performed in patients (n = 8) after infusion of fluorescently labeled antibody, panitumumab-IRDye800 to allow surgical mapping of the tumor specimen. Patients underwent standard of care surgical resection for head and neck squamous cell carcinoma (HNSCC). Optical specimen mapping was performed on the primary tumor specimen and correlated with pathological findings after tissue processing.RESULTS: Optical mapping of the specimen had a 95% sensitivity and 89% specificity to detect cancer within 5 mm (n = 160) of the cut surface. To detect tumor within 2 mm of the specimen surface, the sensitivity of optical specimen mapping was 100%. The maximal observed penetration depth of panitumumab-IRDye800 through human tissue in our study was 6.3 mm.CONCLUSION: Optical specimen mapping is a highly sensitive and specific method for evaluation of margins within <5 mm of the tumor mass in HNSCC specimens. This technology has potentially broad applications for ensuring adequate tumor resection and negative margins in head and neck cancers.
View details for PubMedID 30616798
Visualizing epithelial expression in vertical and horizontal planes with dual axes confocal endomicroscope using compact distal scanner.
IEEE transactions on medical imaging
The epithelium is a thin layer of tissue that lines hollow organs, such as colon. Visualizing in vertical cross sections with sub-cellular resolution is essential to understanding early disease mechanisms that progress naturally in the plane perpendicular to the tissue surface. The dual axes confocal architecture collects optical sections in tissue by directing light at an angle incident to the surface using separate illumination and collection beams to reduce effects of scattering, enhance dynamic range, and increase imaging depth. This configuration allows for images to be collected in the vertical as well as horizontal planes. We designed a fast, compact monolithic scanner based on the principle of parametric resonance. The mirrors were fabricated using microelectromechanical systems (MEMS) technology and were coated with aluminum to maximize near-infrared reflectivity. We achieved large axial displacements [Formula: see text] and wide lateral deflections >20°. The MEMS chip has a 3.2×2.9 mm2 form factor that allows for efficient packaging in the distal end of an endomicroscope. Imaging can be performed in either the vertical or horizontal planes with [Formula: see text] depth or 1 ×1 mm2 area, respectively, at 5 frames/s. We systemically administered a Cy5.5-labeled peptide that is specific for EGFR, and collected near-infrared fluorescence images ex vivo from pre-malignant mouse colonic epithelium to reveal the spatial distribution of this molecular target. Here, we demonstrate a novel scanning mechanism in a dual axes confocal endomicroscope that collects optical sections of near-infrared fluorescence in either vertical or horizontal planes to visualize molecular expression in the epithelium.
View details for DOI 10.1109/TMI.2017.2673022
View details for PubMedID 28252391
Multimodal laser-based angioscopy for structural, chemical and biological imaging of atherosclerosis.
Nature biomedical engineering
The complex nature of atherosclerosis demands high-resolution approaches to identify subtle thrombogenic lesions and define the risk of plaque rupture. Here, we report the proof-of-concept use of a multimodal scanning fiber endoscope (SFE) consisting of a single optical fiber scanned by a piezoelectric drive that illuminates tissue with red, blue, and green laser beams, and digitally reconstructs images at 30 Hz with high resolution and large fields-of-view. By combining laser-induced reflectance and fluorescence emission of intrinsic fluorescent constituents in arterial tissues, the SFE allowed us to co-generate endoscopic videos with a label-free biochemical map to derive a morphological and spectral classifier capable of discriminating early, intermediate, advanced, and complicated atherosclerotic plaques. We demonstrate the capability of scanning fiber angioscopy for the molecular imaging of vulnerable atherosclerosis by targeting proteolytic activity with a fluorescent probe activated by matrix metalloproteinases. We also show that the SFE generates high-quality spectral images in vivo in an animal model with medium-sized arteries. Multimodal laser-based angioscopy could become a platform for the diagnosis, prognosis, and image-guided therapy of atherosclerosis.
View details for DOI 10.1038/s41551-016-0023
View details for PubMedID 28555172
View details for PubMedCentralID PMC5446210
In vivo near-infrared imaging of ErbB2 expressing breast tumors with dual-axes confocal endomicroscopy using a targeted peptide.
2017; 7 (1): 14404
ErbB2 expression in early breast cancer can predict tumor aggressiveness and clinical outcomes in large patient populations. Accurate assessment with physical biopsy and conventional pathology can be limited by tumor heterogeneity. We aim to demonstrate real-time optical sectioning using a near-infrared labeled ErbB2 peptide that generates tumor-specific contrast in human xenograft breast tumors in vivo. We used IRDye800CW as the fluorophore, validated performance characteristics for specific peptide binding to cells in vitro, and investigated peak peptide uptake in tumors using photoacoustic tomography. We performed real-time optical imaging using a handheld dual-axes confocal fluorescence endomicroscope that collects light off-axis to reduce tissue scattering for greater imaging depths. Optical sections in either the vertical or horizontal plane were collected with sub-cellular resolution. Also, we found significantly greater peptide binding to pre-clinical xenograft breast cancer in vivo and to human specimens of invasive ductal carcinoma that express ErbB2 ex vivo. We used a scrambled peptide for control. Peptide biodistribution showed high tumor uptake by comparison with other organs to support safety. This novel integrated imaging strategy is promising for visualizing ErbB2 expression in breast tumors and serve as an adjunct during surgery to improve diagnostic accuracy, identify tumor margins, and stage early cancers.
View details for DOI 10.1038/s41598-017-13735-z
View details for PubMedID 29089571
View details for PubMedCentralID PMC5663926
Ultrasmall Paramagnetic Iron Oxide Nanoprobe Targeting Epidermal Growth Factor Receptor for In Vivo Magnetic Resonance Imaging of Hepatocellular Carcinoma.
2017; 28 (11): 2794–2803
Hepatocellular carcinoma (HCC) is a common worldwide cancer that is rising rapidly in incidence. MRI is a powerful noninvasive imaging modality for HCC detection, but lack of specific contrast agents limits visualization of small tumors. EGFR is frequently overexpressed in HCC and is a promising target. Peptides have fast binding kinetics, short circulatory half-life, low imaging background, high vascular permeability, and enhanced tissue diffusion for deep tumor penetration. We demonstrate a peptide specific for EGFR labeled with an ultrasmall paramagnetic iron oxide (UPIO) nanoparticle with 3.5 nm dimensions to target HCC using T1-weighted MRI. We modified the hydrophobic core with oleic acid and capped with PEGylated phospholipids DSPE-PEG and DSPE-PEG-Mal. The EGFR peptide is attached via thioether-mediated conjugation of a GGGSC linker to the maleimide-terminated phospholipids. On in vivo MR images of HCC xenograft tumors, we observed peak nanoprobe uptake at 2 h post-injection followed by a rapid return to baseline by ∼24 h. We measured significantly greater MR signal in tumor with the targeted nanoprobe versus scrambled peptide, blocked peptide, and Gadoteridol. Segmented regions on MR images support rapid renal clearance. No significant difference in animal weight, necropsy, hematology, and chemistry was found between treatment and control groups at one month post-injection. Our nanoprobe based on an EGFR specific peptide labeled with UPIO designed for high stability and biocompatibility showed rapid tumor uptake and systemic clearance to demonstrate safety and promise for clinical translation to detect early HCC.
View details for DOI 10.1021/acs.bioconjchem.7b00501
View details for PubMedID 28972742
Visualizing epithelial expression of EGFR in vivo with distal scanning side-viewing confocal endomicroscope
Confocal endomicroscopy is an emerging imaging technology that has recently been introduced into the clinic to instantaneously collect "optical biopsies" in vivo with histology-like quality. Here, we demonstrate a fast scanner located in the distal end of a side-viewing instrument using a compact lens assembly with numerical aperture of 0.5 to achieve a working distance of 100 μm and field-of-view of 300 × 400 μm2. The microelectromechanical systems (MEMS) mirror was designed based on the principle of parametric resonance and images at 5 frames per second. The instrument has a 4.2 mm outer diameter and 3 cm rigid length, and can pass through the biopsy channel of a medical endoscope. We achieved real time optical sections of NIR fluorescence with 0.87 μm lateral resolution, and were able to visualize in vivo binding of a Cy5.5-labeled peptide specific for EGFR to the cell surface of pre-cancerous colonocytes within the epithelium of dysplastic crypts in mouse colon. By performing targeted imaging with endomicroscopy, we can visualize molecular expression patterns in vivo that provide a biological basis for disease detection.
View details for DOI 10.1038/srep37315
View details for Web of Science ID 000388228500001
View details for PubMedID 27874037
View details for PubMedCentralID PMC5118792
In vivo fluorescence imaging of hepatocellular carcinoma xenograft using near-infrared labeled epidermal growth factor receptor (EGFR) peptide
BIOMEDICAL OPTICS EXPRESS
2016; 7 (9): 3163-3169
Minimally-invasive surgery of hepatocellular carcinoma (HCC) can be limited by poor tumor visualization with white light. We demonstrate systemic administration of a Cy5.5-labeled peptide specific for epidermal growth factor receptor (EGFR) to target HCC in vivo in a mouse xenograft model. We attached a compact imaging module to the proximal end of a medical laparoscope to collect near-infrared fluorescence and reflectance images concurrently at 15 frames/sec. We measured a mean target-to-background ratio of 2.99 ± 0.22 from 13 surgically exposed subcutaneous human HCC tumors in vivo in 5 mice. This integrated imaging methodology is promising to guide laparoscopic resection of HCC.
View details for DOI 10.1364/BOE.7.003163
View details for Web of Science ID 000385416500001
View details for PubMedID 27699089
View details for PubMedCentralID PMC5030001
In vivo photoacoustic tomography of EGFR overexpressed in hepatocellular carcinoma mouse xenograft.
2016; 4 (2): 43-54
EGFR is a promising cell surface target for in vivo imaging that is highly overexpressed in hepatocellular carcinoma (HCC), a common cancer worldwide. Peptides penetrate easily into tumors for deep imaging, and clear rapidly from the circulation to minimize background. We aim to demonstrate use of an EGFR specific peptide to detect HCC xenograft tumors in mice with photoacoustic imaging. Nude mice implanted with human HCC cells that overexpress EGFR were injected intravenously with Cy5.5-labeled EGFR and scrambled control peptides respectively. Photoacoustic images collected from 0 to 24 h. Photoacoustic signal peaked in tumors at 3 h post-injection. Images from 0 to 1.8 cm beneath the skin revealed increased target-to-background (T/B) ratio from tumors. The T/B ratio was significantly greater for the EGFR versus control peptide. Clearance of signal was observed by ∼24 h. EGFR overexpression was validated with immunofluorescence and immunohistochemistry. A peptide specific for EGFR delivered systemically can detect HCC xenograft tumors in vivo with photoacoustic imaging.
View details for PubMedID 27766208
View details for PubMedCentralID PMC5066077
Integrated monolithic 3D MEMS scanner for switchable real time vertical/horizontal cross-sectional imaging
2016; 24 (3): 2145-2155
We present an integrated monolithic, electrostatic 3D MEMS scanner with a compact chip size of 3.2 × 2.9 mm(2). Use of parametric excitation near resonance frequencies produced large optical deflection angles up to ± 27° and ± 28.5° in the X- and Y-axes and displacements up to 510 μm in the Z-axis with low drive voltages at atmospheric pressure. When packaged in a dual axes confocal endomicroscope, horizontal and vertical cross-sectional images can be collected seamlessly in tissue with a large field-of-view of >1 × 1 mm(2) and 1 × 0.41 mm(2), respectively, at 5 frames/sec.
View details for DOI 10.1364/OE.24.002145
View details for Web of Science ID 000371427100027
View details for PubMedID 26906790
View details for PubMedCentralID PMC5802237
Design and Synthesis of Near-Infrared Peptide for in Vivo Molecular Imaging of HER2
2016; 27 (2): 481-494
We report the development, characterization, and validation of a peptide specific for the extracellular domain of HER2. This probe chemistry was developed for molecular imaging by using a structural model to select an optimal combination of amino acids that maximize the likelihood for unique hydrophobic and hydrophilic interactions with HER2 domain 3. The sequence KSPNPRF was identified and conjugated with either FITC or Cy5.5 via a GGGSK linker using Fmoc-mediated solid-phase synthesis to demonstrate flexibility for this chemical structure to be labeled with different fluorophores. A scrambled sequence was developed for control by altering the conformationally rigid spacer and moving both hydrophobic and hydrophilic amino acids on the C-terminus. We validated peptide specificity for HER2 in knockdown and competition experiments using human colorectal cancer cells in vitro, and measured a binding affinity of kd = 21 nM and time constant of k = 0.14 min(-1) (7.14 min). We used this peptide with either topical or intravenous administration in a preclinical model of colorectal cancer to demonstrate specific uptake in spontaneous adenomas and to show feasibility for real time in vivo imaging with near-infrared fluorescence. We used this peptide in immunofluorescence studies of human proximal colon specimens to evaluate specificity for sessile serrated and sporadic adenomas. Improved visualization can be used endoscopically to guide tissue biopsy and detect premalignant lesions that would otherwise be missed. Our peptide design for specificity to HER2 is promising for clinical translation in molecular imaging methods for early cancer detection.
View details for DOI 10.1021/acs.bioconjchem.5b00565
View details for Web of Science ID 000370582600023
View details for PubMedID 26709709
View details for PubMedCentralID PMC5384256
- Vertical cross-sectional imaging of colonic dysplasia in vivo with multi-spectral dual axes confocal endomicroscopy. Gastroenterology 2014; 146 (3): 615-617