Alzheimer’s disease is characterized by the misfolding and self-assembly of the amyloidogenic protein amyloid-β (Aβ). The aggregation of Aβ leads to diverse oligomeric states, each of which may be potential targets for intervention. Obtaining insight into Aβ oligomers at the atomic level has been a major challenge to most techniques. Here, we use magic angle spinning recoupling 1H-1H NMR experiments to overcome many of these limitations. Using 1H-1H dipolar couplings as a NMR spectral filter to remove both high and low molecular weight species, we provide atomic-level characterization of a non-fibrillar aggregation product of the Aβ1-40 peptide using non-frozen samples without isotopic labeling. Importantly, this spectral filter allows the detection of the specific oligomer signal without a separate purification procedure. In comparison to other solid-state NMR techniques, the experiment is extraordinarily selective and sensitive. A resolved 2D spectra could be acquired of a small population of oligomers (6 micrograms, 7% of the total) amongst a much larger population of monomers and fibers (93% of the total). By coupling real-time 1H-1H NMR experiments with other biophysical measurements, we show that a stable, primarily disordered Aβ1-40 oligomer 5–15 nm in diameter can form and coexist in parallel with the well-known cross-β-sheet fibrils.

Control over the average length of single-walled carbon nanotubes (SWNTs) in suspension is of critical importance to characterizing and developing flexible, transparent thin films that use percolative transport to achieve reproducibility in electronic properties. This paper demonstrates how the average length of SWNTs in aqueous suspensions can be controlled by the conditions used to form (sonication) and purify (low-G centrifugation) the dispersions. The effect of ultrasonic probe sonication, which was used to disperse SWNT bundles into suspension, on the length and extent of defects on the nanotubes was investigated via atomic force microscopy (AFM) and confocal Raman spectroscopy, respectively. Quantitative information about the suspension concentration and the effect of sonication power on unbundling the SWNTs was obtained via UV−vis and near-IR spectroscopy, respectively. To obtain a clear understanding of the effect of sonication power on SWNT suspensions, repeated low-G centrifugation cycles were used to remove impurities such as bundles of SWNTs, amorphous carbon, and catalyst nanoparticles. This nonoxidizing purification method, which was performed prior to all analyses, allows direct determination of the effect of sonication power on defect formation.

Angiogenesis, i.e. the formation of neovasculatures, is a critical process during cancer initiation, progression, and metastasis. Targeting of angiogenic markers on the tumor vasculature can result in more efficient delivery of nanomaterials into tumor since no extravasation is required. Herein we demonstrated efficient targeting of breast cancer metastasis in an experimental murine model with nano-graphene oxide (GO), which was conjugated to a monoclonal antibody (mAb) against follicle-stimulating hormone receptor (FSHR). FSHR has been confirmed to be a highly selective tumor vasculature marker, which is abundant in both primary and metastatic tumors. These functionalized GO nano-conjugates had diameters of ~ 120 nm based on atomic force microscopy (AFM), TEM, and dynamic laser scattering (DLS) measurement. 64 Cu was incorporated as a radiolabel which enabled the visualization of these GO conjugates by positron emission tomography (PET) imaging. Breast cancer lung metastasis model was established by intravenous injection of click beetle green luciferase-transfected MDA-MB-231 (denoted as cbgLuc-MDA-MB-231) breast cancer cells into female nude mice and the tumor growth was monitored by bioluminescence imaging (BLI). Systematic in vitro and in vivo studies have been performed to investigate the stability, targeting efficacy and specificity, and tissue distribution of GO conjugates. Flow cytometry and fluorescence microscopy examination confirmed the targeting specificity of FSHR-mAb attached GO conjugates against cellular FSHR. More potent and persistent uptake of 64 Cu-NOTA-GO-FSHR-mAb in cbgLuc-MDA-MB-231 nodules inside the lung was witnessed HHS Public Access Author ManuscriptAuthor Manuscript Author ManuscriptAuthor Manuscript when compared with that of non-targeted GO conjugates ( 64 Cu-NOTA-GO). Histology evaluation also confirmed the vasculature accumulation of GO-FSHR-mAb conjugates in tumor at early time points while they were non-specifically captured in liver and spleen. In addition, these GO conjugates can serve as good drug carriers with satisfactory drug loading capacity (e.g. for doxorubicin [DOX], 756 mg/g). Enhanced drug delivery efficiency in cbgLuc-MDA-MB-231 metastatic sites was demonstrated in DOX-loaded GO-FSHR-mAb by fluorescence imaging. This FSHR-targeted, GO-based nanoplatform can serve as a useful tool for early metastasis detection and targeted delivery of therapeutics. Graphical Abstract KeywordsNano-graphene oxide (GO); Angiogenesis; Follicle-stimulating hormone receptor (FSHR); Breast cancer metastasis; Positron emission tomography (PET); Image-guided drug delivery

Two independent biological replicates of estrogen depletion were employed with differing drug treatment conditions. Data Set I consisted of 9-month-old New Zealand white female rabbits treated as follows: sham-operated (n ¼ 11), ovariectomized (OVX; n ¼ 12), OVX þ 200 mg kg À 1 alendronate (ALN), 3 Â a week for 27 weeks (n ¼ 12) and OVX þ 10 mg kg À 1 Cathepsin-K inhibitor (CatKI) daily for 27 weeks. Data Set II consisted of 6-month-old New Zealand white female rabbits that were sham-operated (n ¼ 12), OVX (n ¼ 12) or OVX þ 0.05 mg kg À 1 17b-estradiol (ERT) 3 Â a week for 13 weeks (n ¼ 12). Samples from the cortical femur were polished and demineralized to make them suitable for atomic force microscopy (AFM) imaging. Type I collagen fibrils present in bundles or sheets, running parallel to each other, were combined into a class termed Parallel. Fibrils present outside of such structures, typically in images with an angular range of non-parallel fibrils, were combined into a class termed Oblique. The percentage of fibrils coded as Parallel for Sham animals in Data Sets I and II was 52% and 53%, respectively. The percentage of fibrils coded as Parallel for OVX animals in Data Sets I and II was 35% in both cases. ALN and ERT drug treatments reduced the change from 18 to 12%, whereas CatKI treatment reduced the change to 5%.

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