Meike L. Schipper

Bio: Meike L. Schipper is an academic researcher from Stanford University. The author has contributed to research in topics: Biodistribution & Gene. The author has an hindex of 9, co-authored 12 publications receiving 1848 citations.

A pilot toxicology study of single-walled carbon nanotubes in a small sample of mice

Abstract: Single-walled carbon nanotubes are currently under evaluation in biomedical applications, including in vivo delivery of drugs, proteins, peptides and nucleic acids (for gene transfer or gene silencing), in vivo tumour imaging and tumour targeting of single-walled carbon nanotubes as an anti-neoplastic treatment However, concerns about the potential toxicity of single-walled carbon nanotubes have been raised Here we examine the acute and chronic toxicity of functionalized single-walled carbon nanotubes when injected into the bloodstream of mice Survival, clinical and laboratory parameters reveal no evidence of toxicity over 4 months Upon killing, careful necropsy and tissue histology show age-related changes only Histology and Raman microscopic mapping demonstrate that functionalized single-walled carbon nanotubes persisted within liver and spleen macrophages for 4 months without apparent toxicity Although this is a preliminary study with a small group of animals, our results encourage further confirmation studies with larger groups of animals

Particle Size, Surface Coating, and PEGylation Influence the Biodistribution of Quantum Dots in Living Mice

Abstract: This study evaluates the influence of particle size, PEGylation, and surface coating on the quantitative biodistribution of near-infrared-emitting quantum dots (QDs) in mice. Polymer- or peptide-coated 64Cu-labeled QDs 2 or 12 nm in diameter, with or without polyethylene glycol (PEG) of molecular weight 2000, are studied by serial micropositron emission tomography imaging and region-of-interest analysis, as well as transmission electron microscopy and inductively coupled plasma mass spectrometry. PEGylation and peptide coating slow QD uptake into the organs of the reticuloendothelial system (RES), liver and spleen, by a factor of 6-9 and 2-3, respectively. Small particles are in part renally excreted. Peptide-coated particles are cleared from liver faster than physical decay alone would suggest. Renal excretion of small QDs and slowing of RES clearance by PEGylation or peptide surface coating are encouraging steps toward the use of modified QDs for imaging living subjects.

Noninvasive Raman Spectroscopy in Living Mice for Evaluation of Tumor Targeting with Carbon Nanotubes

Abstract: An optimized noninvasive Raman microscope was used to evaluate tumor targeting and localization of single walled carbon nanotubes (SWNTs) in mice. Raman images were acquired in two groups of tumor-bearing mice. The control group received plain-SWNTs, whereas the experimental group received tumor targeting RGD-SWNTs intravenously. Raman imaging commenced over the next 72 h and revealed increased accumulation of RGD-SWNTs in tumor (p < 0.05) as opposed to plain-SWNTs. These results support the development of a new preclinical Raman imager.

microPET-Based Biodistribution of Quantum Dots in Living Mice

Abstract: This study evaluates the quantitative biodistribution of commercially available CdSe quantum dots (QD) in mice. Methods: 64Cu-Labeled 800- or 525-nm emission wavelength QD (21- or 12-nm diameter), with or without 2,000 MW (molecular weight) polyethylene glycol (PEG), were injected intravenously into mice (5.55 MBq/25 pmol QD) and studied using well counting or by serial microPET and region-of-interest analysis. Results: Both methods show rapid uptake by the liver (27.4–38.9 %ID/ g) (%ID/g is percentage injected dose per gram tissue) and spleen (8.0–12.4 %ID/g). Size has no influence on biodistribution within the range tested here. Pegylated QD have slightly slower uptake into liver and spleen (6 vs. 2 min) and show additional low-level bone uptake (6.5–6.9 %ID/g). No evidence of clearance from these organs was observed.Conclusion: Rapid reticuloendothelial system clearance of QD will require modification of QD for optimal utility in imaging living subjects. Formal quantitative biodistribution/imaging studies will be helpful in studying many types of nanoparticles, including quantum dots.

Targeted Microbubbles for Imaging Tumor Angiogenesis: Assessment of Whole-Body Biodistribution with Dynamic Micro-PET in Mice

Abstract: Purpose: To evaluate in vivo whole-body biodistribution of microbubbles (MBs) targeted to tumor angiogenesis–related vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2) by using dynamic micro–positron emission tomography (PET) in living mice. Materials and Methods: Animal protocols were approved by the Institutional Administrative Panel on Laboratory Animal Care. Lipid-shell perfluorocarbon-filled MBs, targeted to VEGFR2 via anti-VEGFR2 antibodies, were radiolabeled by conjugating the radiofluorination agent N-succinimidyl-4-[18F]fluorobenzoate (SFB) to the anti-VEGFR2 antibodies. These MBs were then injected intravenously into nude mice (n = 4) bearing angiosarcomas, and the whole-body biodistribution of these probes was assessed for 60 minutes by using dynamic micro-PET. Results were compared with ex vivo gamma counting (n = 6) and immunofluorescence staining (n = 6). Control studies in angiosarcoma-bearing mice were performed with injection of the radiolabeled antibodies alone (n = 3) or free...

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

The effect of nanoparticle size, shape, and surface chemistry on biological systems.

Abstract: An understanding of the interactions between nanoparticles and biological systems is of significant interest. Studies aimed at correlating the properties of nanomaterials such as size, shape, chemical functionality, surface charge, and composition with biomolecular signaling, biological kinetics, transportation, and toxicity in both cell culture and animal experiments are under way. These fundamental studies will provide a foundation for engineering the next generation of nanoscale devices. Here, we provide rationales for these studies, review the current progress in studies of the interactions of nanomaterials with biological systems, and provide a perspective on the long-term implications of these findings.

Molecular imaging in living subjects: seeing fundamental biological processes in a new light

Abstract: References http://genesdev.cshlp.org/content/17/5/545.full.html#related-urls Article cited in: http://genesdev.cshlp.org/content/17/5/545.full.html#ref-list-1 This article cites 228 articles, 79 of which can be accessed free at: service Email alerting click here top right corner of the article or Receive free email alerts when new articles cite this article sign up in the box at the Collections Topic (33 articles) Molecular Physiology and Metabolism • (98 articles) Cancer and Disease Models • Articles on similar topics can be found in the following collections

Graphene in Mice: Ultrahigh In Vivo Tumor Uptake and Efficient Photothermal Therapy

Abstract: Although biomedical applications of carbon nanotubes have been intensively studied in recent years, its sister, graphene, has been rarely explored in biomedicine. In this work, for the first time we study the in vivo behaviors of nanographene sheets (NGS) with polyethylene glycol (PEG) coating by a fluorescent labeling method. In vivo fluorescence imaging reveals surprisingly high tumor uptake of NGS in several xenograft tumor mouse models. Distinctive from PEGylated carbon nanotubes, PEGylated NGS shows several interesting in vivo behaviors including highly efficient tumor passive targeting and relatively low retention in reticuloendothelial systems. We then utilize the strong optical absorbance of NGS in the near-infrared (NIR) region for in vivo photothermal therapy, achieving ultraefficient tumor ablation after intravenous administration of NGS and low-power NIR laser irradiation on the tumor. Furthermore, no obvious side effect of PEGylated NGS is noted for the injected mice by histology, blood chemi...

Near-infrared fluorophores for biomedical imaging

Abstract: This Review covers recent progress on near-infrared fluorescence imaging for preclinical animal studies and clinical diagnostics and interventions.