Enhancing T1 magnetic resonance imaging contrast with internalized gadolinium(III) in a multilayer nanoparticle.

Multifunctional nanoparticles for biomedical applications have shown extraordinary potential as contrast agents in various bioimaging modalities, near-IR photothermal therapy, and for light-triggered therapeutic release processes. Over the past several years, numerous studies have been performed to synthesize and enhance MRI contrast with nanoparticles. However, understanding the MRI enhancement mechanism in a multishell nanoparticle geometry, and controlling its properties, remains a challenge. To systematically examine MRI enhancement in a nanoparticle geometry, we have synthesized MRI-active Au nanomatryoshkas. These are Au core-silica layer-Au shell nanoparticles, where Gd(III) ions are encapsulated within the silica layer between the inner core and outer Au layer of the nanoparticle (Gd-NM). This multifunctional nanoparticle retains its strong near-IR Fano-resonant optical absorption properties essential for photothermal or other near-IR light-triggered therapy, while simultaneously providing increased T1 contrast in MR imaging by concentrating Gd(III) within the nanoparticle. Measurements of Gd-NM revealed a strongly enhanced T1 relaxivity (r1 ∼ 24 mM-1⋅s-1) even at 4.7 T, substantially surpassing conventional Gd(III) chelating agents (r1 ∼ 3 mM-1⋅s-1 at 4.7 T) currently in clinical use. By varying the thickness of the outer gold layer of the nanoparticle, we show that the observed relaxivities are consistent with Solomon-Bloembergen-Morgan (SBM) theory, which takes into account the longer-range interactions between the encapsulated Gd(III) and the protons of the H2O molecules outside the nanoparticle. This nanoparticle complex and its MRI T1-enhancing properties open the door for future studies on quantitative tracking of therapeutic nanoparticles in vivo, an essential step for optimizing light-induced, nanoparticle-based therapies.

Ultrastructural Location and Interactions of the Immunoglobulin Receptor Binding Sequence within Fibrillar Type I Collagen.

Collagen type I is a major constituent of animal bodies. It is found in large quantities in tendon, bone, skin, cartilage, blood vessels, bronchi, and the lung interstitium. It is also produced and accumulates in large amounts in response to certain inflammations such as lung fibrosis. Our understanding of the molecular organization of fibrillar collagen and cellular interaction motifs, such as those involved with immune-associated molecules, continues to be refined. In this study, antibodies raised against type I collagen were used to label intact D-periodic type I collagen fibrils and observed with atomic force microscopy (AFM), and X-ray diffraction (XRD) and immunolabeling positions were observed with both methods. The antibodies bind close to the C-terminal telopeptide which verifies the location and accessibility of both the major histocompatibility complex (MHC) class I (MHCI) binding domain and C-terminal telopeptide on the outside of the collagen fibril. The close proximity of the C-telopeptide and the MHC1 domain of type I collagen to fibronectin, discoidin domain receptor (DDR), and collagenase cleavage domains likely facilitate the interaction of ligands and receptors related to cellular immunity and the collagen-based Extracellular Matrix.

Prognosis for patients with metastatic breast cancer who achieve a no-evidence-of-disease status after systemic or local therapy.

BACKGROUND: This study sought to determine outcomes for patients with metastatic breast cancer (MBC) with no evidence of disease (NED) after treatment and to identify factors predictive of outcomes once the status of NED was attained. METHODS: This study reviewed 570 patients with MBC who were consecutively treated between January 2003 and December 2005. Ninety patients (16%) attained NED, which was defined as a complete metabolic response on positron emission tomography or sclerotic healing of bone metastases on computed tomography or magnetic resonance imaging. The median follow-up for patients attaining NED was 100 months (range, 14-134 months). RESULTS: The 3- and 5-year overall survival (OS) rates were 44% and 24%, respectively, for the entire group and 96% and 78%, respectively, for those attaining NED. According to a landmark analysis, NED status was significantly associated with survival at 2 (P < .001; hazard ratio [HR], 0.23; 95% confidence interval [CI], 0.16-0.34) and 3 years (P < .001; HR, 0.20; 95% CI, 0.14-0.30). From the time of NED, the median survival was 102 months (range, 14-134 months) with 5-year OS and progression-free survival (PFS) rates of 77% and 40%, respectively. According to a multivariate analysis, human epidermal growth factor receptor 2 positivity was significantly associated with OS in comparison with estrogen receptor positivity (P = .02; HR, 0.44; 95% CI, 0.21-0.90), and trastuzumab use was significantly associated with PFS (P = .007; HR, 0.48; 95% CI, 0.28-0.82). Thirty-one patients (34%) with NED remained in remission at the last follow-up. CONCLUSIONS: MBC patients who attain the status of NED have significantly prolonged survival with a durable response to therapy. Ultimately, this study provides essential outcome data for clinicians and patients living with MBC.

SERS biodetection using gold-silica nanoshells and nitrocellulose membranes.

We have developed a rapid, reproducible, easy to execute, surface enhanced Raman scattering (SERS) method for detection of low volumes and total amounts of biological antigens using an analyte capture system derived from methods commonly used in Western blotting. Our method is a "half-sandwich" assay with an antigen detection scheme that employs a nitrocellulose (NC) membrane with 200 nm pore size to capture subnanograms of analyte and concentrate them in a small area from applied volumes as low as one microliter. The SERS probes used for detection consist of gold-silica nanoshells modified with a two-component mixed monolayer system. One component consists of a poly(ethylene glycol) (PEG)-modified Raman-active chromophore bound to the gold surface which allows for SERS detection and imparts particle stability. The second component uses (ortho-pyridyl) disulfide-PEG-succinimidyl ester to couple the recognition antibody to the particle surface. By controlling the reaction time and concentration of thiols, a mixed monolayer is prepared on the nanoshell surface with the ability to recognize low concentrations of analyte and generate reproducible SERS signals. Using this strategy, we have achieved SERS signals that are proportional to antigen present on the membrane allowing detection of total antigen amounts as low as 1.25 ng for some cases. The performance of this new SERS bioassay has been tested with a variety of potential antigens, demonstrating the potential for multiplexed detection of analytes.

Comparative toxicity study of Ag, Au, and Ag-Au bimetallic nanoparticles on Daphnia magna.

A comparative assessment of the 48-h acute toxicity of aqueous nanoparticles synthesized using the same methodology, including Au, Ag, and Ag-Au bimetallic nanoparticles, was conducted to determine their ecological effect in freshwater environments through the use of Daphnia magna, using their mortality as a toxicological endpoint. D. magna are one of the standard organisms used for ecotoxicity studies due to their sensitivity to chemical toxicants. Particle suspensions used in toxicity testing were well-characterized through a combination of absorbance measurements, atomic force or electron microscopy, flame atomic absorption spectrometry, and dynamic light scattering to determine composition, aggregation state, and particle size. The toxicity of all nanoparticles tested was found to be dose and composition dependent. The concentration of Au nanoparticles that killed 50% of the test organisms (LC(50)) ranged from 65-75 mg/L. In addition, three different sized Ag nanoparticles (diameters = 36, 52, and 66 nm) were studied to analyze the toxicological effects of particle size on D. magna; however, it was found that toxicity was not a function of size and ranged from 3-4 µg/L for all three sets of Ag nanoparticles tested. This was possibly due to the large degree of aggregation when these nanoparticles were suspended in standard synthetic freshwater. Moreover, the LC(50) values for Ag-Au bimetallic nanoparticles were found to be between that of Ag and Au but much closer to that of Ag. The bimetallic particles containing 80% Ag and 20% Au were found to have a significantly lower toxicity to Daphnia (LC(50) of 15 µg/L) compared to Ag nanoparticles, while the toxicity of the nanoparticles containing 20% Ag and 80% Au was greater than expected at 12 µg/L. The comparison results confirm that Ag nanoparticles were much more toxic than Au nanoparticles, and that the introduction of gold into silver nanoparticles may lower their environmental impact by lowering the amount of Ag which is bioavailable.

Rapid Raman imaging of stable, functionalized nanoshells in mammalian cell cultures.

Two Raman-active poly(ethylene glycol) (PEG) molecules, one linear (MW 5000) and the other branched (MW 2420), are synthesized to stabilize gold-silica nanoshells in cell culture media and track nanoparticles in mammalian cell cultures. The linear PEG provides greater nanoshell stability in saline solution compared to commercially available PEG-thiol or the branched PEG. Surface enhanced Raman scattering rapidly tracks the probes and provides semiquantitative information regarding particle localization within mouse macrophage (RAW 264.7) and human breast cancer (MCF 7) cell cultures.

Survivorship and Advocacy in Inflammatory Breast Cancer.

In February 2017, the Morgan Welch Inflammatory Breast Cancer (IBC) Research Program and Clinic hosted a scientific conference in Houston to commemorate the tenth anniversary of the opening of the first IBC-dedicated clinic in the world. Attendees included basic science researchers, clinicians who treat IBC, as well as patients and their caregivers. Several US-based and international IBC-focused nonprofit organizations were also represented. In this third paper from the conference, we report on the breakout session regarding survivorship and advocacy issues related to IBC, sharing an overview of the educational content presented and discussions regarding the future of IBC advocacy. Panelists focused on lymphedema research and clinical solutions, integrative medicine, and social work, with time provided for questions in small groups. IBC nonprofits that are leading advocacy efforts were introduced, and ways to become involved in these initiatives were discussed. Priorities for future advocacy and clinical care needs were also highlighted. In addition to summarizing these topics, we provide a suggested integrated IBC-specific plan of care that could be provided to the patient at the beginning of care and referred to throughout treatment and follow-up.

Multifunctionalization of Gold Nanoshells.

Gold silica nanoshells have found many applications within the field of molecular biology, including as nanoscale sensors, the detection of biomarkers, and in the treatment of solid tumors using photothermal ablation. In order for them to be targeted to specific biomarkers while also remaining stable in biological media, it is often necessary to modify their surfaces with more than one functional group. Here, we describe how to create multifunctional gold nanoshells that can be used to either target specific tumor types in vivo or for the detection of biomarkers using biological specimen.

Sub-100nm gold nanomatryoshkas improve photo-thermal therapy efficacy in large and highly aggressive triple negative breast tumors.

There is an unmet need for efficient near-infrared photothermal transducers for the treatment of highly aggressive cancers and large tumors where the penetration of light can be substantially reduced, and the intra-tumoral nanoparticle transport is restricted due to the presence of hypoxic or necrotic regions. We report the performance advantages obtained by sub 100nm gold nanomatryushkas, comprising concentric gold-silica-gold layers compared to conventional ~150nm silica core gold nanoshells for photothermal therapy of triple negative breast cancer. We demonstrate that a 33% reduction in silica-core-gold-shell nanoparticle size, while retaining near-infrared plasmon resonance, and keeping the nanoparticle surface charge constant, results in a four to five fold tumor accumulation of nanoparticles following equal dose of injected gold for both sizes. The survival time of mice bearing large (>1000mm(3)) and highly aggressive triple negative breast tumors is doubled for the nanomatryushka treatment group under identical photo-thermal therapy conditions. The higher absorption cross-section of a nanomatryoshka results in a higher efficiency of photonic to thermal energy conversion and coupled with 4-5× accumulation within large tumors results in superior therapy efficacy.

Au nanomatryoshkas as efficient near-infrared photothermal transducers for cancer treatment: benchmarking against nanoshells.

Au nanoparticles with plasmon resonances in the near-infrared (NIR) region of the spectrum efficiently convert light into heat, a property useful for the photothermal ablation of cancerous tumors subsequent to nanoparticle uptake at the tumor site. A critical aspect of this process is nanoparticle size, which influences both tumor uptake and photothermal efficiency. Here, we report a direct comparative study of ∼90 nm diameter Au nanomatryoshkas (Au/SiO2/Au) and ∼150 nm diameter Au nanoshells for photothermal therapeutic efficacy in highly aggressive triple negative breast cancer (TNBC) tumors in mice. Au nanomatryoshkas are strong light absorbers with 77% absorption efficiency, while the nanoshells are weaker absorbers with only 15% absorption efficiency. After an intravenous injection of Au nanomatryoshkas followed by a single NIR laser dose of 2 W/cm(2) for 5 min, 83% of the TNBC tumor-bearing mice appeared healthy and tumor free >60 days later, while only 33% of mice treated with nanoshells survived the same period. The smaller size and larger absorption cross section of Au nanomatryoshkas combine to make this nanoparticle more effective than Au nanoshells for photothermal cancer therapy.

Modeling the cellular impact of nanoshell-based biosensors using mouse alveolar macrophage cultures.

In this study, the relative toxicity of native gold-silica nanoshells (NS) has been compared to nanoshells modified with poly(ethylene glycol)-thiol (PEG-SH) and a Raman-active PEG, p-mercaptoaniline-poly(ethylene glycol) (pMA-PEG), in mouse alveolar macrophage cell cultures (RAW 264.7). The results from toxicity profiling using an MTT assay demonstrate that cell viability post-particle exposure is a function of three factors: nanoshell concentration, surface functionalization, and incubation time. By minimizing particle concentrations and incubation times, cell cultures are able to recover within 24 h of nanoshell removal, indicative of nanoshells having more of a cytostatic versus cytotoxic effect on macrophage cells. The mechanism of the cytostatic effect has been investigated by imaging the presence of reactive oxygen species (ROS) using a fluorescence assay kit (Image-iT™ LIVE) after the introduction of NS to the cell cultures. Elevated ROS signals are seen in the cells containing higher concentration of NS, and indicate that the major reason of toxicity may due to the oxidative stress caused by excess NS particles. Raman imaging experiments with pMA-PEG coated nanoshells showed that cells exposed for even short exposure times (∼2 h) retained those particles up to 24 h after exposure, while migration experiments suggest that surviving cells retain their nanoshells and may reallocate them to progeny cells upon cell division.

The role of protein binding in the poisoning of gold nanoparticle catalysts.

Seed mediated catalytic growth of gold nanoparticles is used in the design of biosensors for the products of peroxidase proteins, though the role of in situ proteins and the enzymes themselves on the sensitivity of these biosensors is yet to be addressed. This work specifically focuses on whether the presence of proteins with a strong attraction to the gold nanoparticle seeds, such as albumin proteins, inhibits the nanoparticle's catalytic properties. We have determined that the sensitivity of the biosensor design, defined as its response to the reducing agent hydrogen peroxide, is highly dependent on the presence of bovine serum albumin (BSA) and less dependent on the presence of the enzyme glucose oxidase. We suggest that the strong interaction between BSA and the gold surface leads to poisoning of the catalytic sites on the particle surface, which reduces the uniform growth of the nanoparticles and increases asymmetric growth of small gold nanoparticles onto the seed surface. The overall effect of the protein interaction is to lower the sensitivity of the model biosensor.

Determining the conformation of thiolated poly(ethylene glycol) on Au nanoshells by surface-enhanced Raman scattering spectroscopic assay.

The packing density of thiolated poly(ethylene glycol) (PEG) adsorbates on Au nanoshells is determined by exploiting the surface-enhanced Raman scattering response of individual nanoshell substrates. By incorporating the linker molecule p-mercaptoaniline (pMA), the number of 2000 MW and 5000 MW PEG molecules on each nanoparticle is determined by interpolation of the Langmuir isotherm for pMA. We conclude that both PEG adsorbates maintain a compact "brush" rather than an extended "mushroom" configuration on nanoshell surfaces.

All-optical nanoscale pH meter.

We show that an Au nanoshell with a pH-sensitive molecular adsorbate functions as a standalone, all-optical nanoscale pH meter that monitors its local environment through the pH-dependent surface-enhanced Raman scattering (SERS) spectra of the adsorbate molecules. Moreover, we also show how the performance of such a functional nanodevice can be assessed quantitatively. The complex spectral output is reduced to a simple device characteristic by application of a locally linear manifold approximation algorithm. The average accuracy of the nano-"meter" was found to be +/-0.10 pH units across its operating range.