Nanoparticle-mediated systemic delivery of siRNA for treatment of cancers and viral infections.

RNA interference (RNAi) is an endogenous post-transcriptional gene regulatory mechanism, where non-coding, double-stranded RNA molecules interfere with the expression of certain genes in order to silence it. Since its discovery, this phenomenon has evolved as powerful technology to diagnose and treat diseases at cellular and molecular levels. With a lot of attention, short interfering RNA (siRNA) therapeutics has brought a great hope for treatment of various undruggable diseases, including genetic diseases, cancer, and resistant viral infections.

Proteomic analysis of cellular response induced by multi-walled carbon nanotubes exposure in A549 cells.

The wide application of multi-walled carbon nanotubes (MWCNT) has raised serious concerns about their safety on human health and the environment. However, the potential harmful effects of MWCNT remain unclear and contradictory. To clarify the potentially toxic effects of MWCNT and to elucidate the associated underlying mechanisms, the effects of MWCNT on human lung adenocarcinoma A549 cells were examined at both the cellular and the protein level.

Convection-enhanced delivery of targeted quantum dot-immunoliposome hybrid nanoparticles to intracranial brain tumor models.

Aim: The aim of this work is to evaluate combining targeting strategy and convection-enhanced delivery in brain tumor models by imaging quantum dot-immunoliposome hybrid nanoparticles.

Materials & Methods: An EGF receptor-targeted, quantum dot-immunoliposome hybrid nanoparticle (QD-IL) was synthesized. In vitro uptake was measured by flow cytometry and intracellular localization was imaged by confocal microscopy.

Quantum dot-related genotoxicity perturbation can be attenuated by PEG encapsulation.

Nanomaterial-biosystem interaction is emerging as a major concern hindering wide adoption of nanomaterials. Using quantum dots (Qdots) of different sizes (Qdot-440nm and Qdot-680nm) as a model system, we studied the effects of polyethylene glycol (PEG) thin-layer surface modification in attenuating Qdot-related cytotoxicity, genotoxicity perturbation and oxidative stress in a cellular system. We found that uncoated Qdots (U-Qdots) made of core/shell CdSe/ZnS could indeed induce cytotoxic effects, including the inhibition of cell growth.

Hybrid nanocluster plasmonic resonator for immunological detection of hepatitis B virus.

Approximately 88% of the world population lives in regions with intermediate to high incidence of Hepatitis B virus (HBV), yet current serological and DNA-based detection methods have limited sensitivity and convenience. Here, we describe a preassembled plasmonic resonance nanocluster for HBV detection. The gold nanoparticle acceptors (AuNPs), with HBV surface antigen (HBsAg) epitope, and quantum dot (QD) donors with Fab antibody, are assembled into an immuno-mediated 3D-oriented complex with enhanced energy transfer and fluorescence quenching.

Effects of Fluid Shear Stress on a Distinct Population of Vascular Smooth Muscle Cells.

Vascular smooth muscle cells (SMCs) are a major cell type involved in vascular remodeling. The various developmental origins of SMCs such as neural crest and mesoderm result in heterogeneity of SMCs, which plays an important role in the development of vascular remodeling and diseases. Upon vascular injury, SMCs are exposed to blood flow and subjected to fluid shear stress.

Fabrication of quantum dots-encoded microbeads with a simple capillary fluidic device and their application for biomolecule detection.

Monodispersed quantum dots (QDs)-encoded polymer microbeads were generated using a simple capillary fluidic device (CFD). The polymer and QDs solution was emulsified into monodispersed microdroplets by the CFD and obtained droplets were solidified via solvent evaporation. Polymer microbeads can be fabricated in a range of different sizes through changing the flow rates of the two immiscible phases, and have a highly narrow size distribution and uniform shape.

Time-resolved single-step protease activity quantification using nanoplasmonic resonator sensors.

Protease activity measurement has broad application in drug screening, diagnosis and disease staging, and molecular profiling. However, conventional immunopeptidemetric assays (IMPA) exhibit low fluorescence signal-to-noise ratios, preventing reliable measurements at lower concentrations in the clinically important picomolar to nanomolar range. Here, we demonstrated a highly sensitive measurement of protease activity using a nanoplasmonic resonator (NPR).

Picomolar sensitivity MRI and photoacoustic imaging of cobalt nanoparticles.

Multimodality imaging based on complementary detection principles has broad clinical applications and promises to improve the accuracy of medical diagnosis. This means that a tracer particle advantageously incorporates multiple functionalities into a single delivery vehicle. In the present work, we explore a unique combination of MRI and photoacoustic tomography (PAT) to detect picomolar concentrations of nanoparticles.

Facile functionalization of multilayer fullerenes (carbon nano-onions) by nitrene chemistry and "grafting from" strategy.

Facile functionalization of multilayer fullerenes (carbon nano-onions, CNOs) was carried out by [2+1] cycloaddition of nitrenes. The products were further derivatized by using the "grafting from" strategy of in situ ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP). Using one-step nitrene chemistry with high-energy reagents, such as azidoethanol and azidoethyl 2-bromo-2-methyl propanoate, in N-methyl-2-pyrrolidone at 160 degrees C for 16 h, hydroxyl and bromide functionalities were introduced onto the surfaces of CNOs.

Quantitative and label-free technique for measuring protease activity and inhibition using a microfluidic cantilever array.

We report the use of a SiN x based gold coated microcantilever array to quantitatively measure the activity and inhibition of a model protease immobilized on its surface. Trypsin was covalently bound to the gold surface of the microcantilever using a synthetic spacer, and the remaining exposed silicon nitride surface was passivated with silanated polyethylene glycol. The nanoscale cantilever motions induced by trypsin during substrate turnover were quantitatively measured using an optical laser-deflection technique.

Targeted tumor cell internalization and imaging of multifunctional quantum dot-conjugated immunoliposomes in vitro and in vivo.

Targeted drug delivery systems that combine imaging and therapeutic modalities in a single macromolecular construct may offer advantages in the development and application of nanomedicines. To incorporate the unique optical properties of luminescent quantum dots (QDs) into immunoliposomes for cancer diagnosis and treatment, we describe the synthesis, biophysical characterization, tumor cell-selective internalization, and anticancer drug delivery of QD-conjugated immunoliposome-based nanoparticles (QD-ILs). Pharmacokinetic properties and in vivo imaging capability of QD-ILs were also investigated.

Peptide-nanoparticle hybrid SERS probes for optical detection of protease activity.

Real-time in situ detection of active proteases is crucial for early-stage cancer screening and cell signaling pathway study; however, it is difficult to achieve using fluorescence or radioactive probes at volumes below 1 nL. Here we demonstrated a hybrid optical probe by incorporating nanocrescent particle and peptides with artificial tag molecules. We performed a proof-of-concept study using prostate specific antigen (PSA), one of the most prominent prostate cancer markers, and a serine protease present in patients' seminal fluid and serum.

Charge-associated effects of fullerene derivatives on microbial structural integrity and central metabolism.

The effects of four types of fullerene compounds (C60, C60-OH, C60-COOH, C60-NH2) were examined on two model microorganisms (Escherichia coli W3110 and Shewanella oneidensis MR-1). Positively charged C60-NH2 at concentrations as low as 10 mg/L inhibited growth and reduced substrate uptake for both microorganisms. Scanning electron microscopy (SEM) revealed damage to cellular structures.

Qdot nanobarcodes for multiplexed gene expression analysis.

We report a quantum dot (Qdot) nanobarcode-based microbead random array platform for accurate and reproducible gene expression profiling in a high-throughput and multiplexed format. Four different sizes of Qdots, with emissions at 525, 545, 565, and 585 nm are mixed with a polymer and coated onto the 8-mum-diameter magnetic microbeads to generate a nanobarcoded bead termed as QBeads. Twelve intensity levels for each of the four colors were used.

Cellular effect of high doses of silica-coated quantum dot profiled with high throughput gene expression analysis and high content cellomics measurements.

Quantum dots (Qdots) are now used extensively for labeling in biomedical research, and this use is predicted to grow because of their many advantages over alternative labeling methods. Uncoated Qdots made of core/shell CdSe/ZnS are toxic to cells because of the release of Cd2+ ions into the cellular environment. This problem has been partially overcome by coating Qdots with polymers, poly(ethylene glycol) (PEG), or other inert molecules.

A comparative study of using comet assay and gammaH2AX foci formation in the detection of N-methyl-N'-nitro-N-nitrosoguanidine-induced DNA damage.

Comet assay is a useful technique in the detection of DNA damages, particularly DNA strand breaks; and it has been utilized to show that a potent carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), can induce such damages. Recently, gammaH2AX foci formation has been suggested as another sensitive way to detect DNA double strand breaks (DSBs). However, there is no systematic comparison being conducted to evaluate the consistency of these two methods.

Lithographic techniques and surface chemistries for the fabrication of PEG-passivated protein microarrays.

This article presents a new technique to fabricate patterns of functional molecules surrounded by a coating of the inert poly(ethylene glycol) (PEG) on glass slides for applications in protein microarray technology. The chief advantages of this technique are that it is based entirely on standard lithography processes, makes use of glass slides employing surface chemistries that are standard in the microarray community, and has the potential to massively scale up the density of microarray spots. It is shown that proteins and antibodies can be made to self-assemble on the functional patterns in a microarray format, with the PEG coating acting as an effective passivating agent to prevent non-specific protein adsorption.

DNA damage evaluated by gammaH2AX foci formation by a selective group of chemical/physical stressors.

It has been reported that the phosphorylated form of histone variant H2AX (gammaH2AX) plays an important role in the recruitment of DNA repair and checkpoint proteins to sites of DNA damage, particularly at double strand breaks (DSBs). Using gammaH2AX foci formation as an indicator for DNA damage, several chemicals/stress factors were chosen to assess their ability to induce gammaH2AX foci in a 24h time frame in a human amnion FL cell line. Two direct-acting genotoxins, methyl methanesulfonate (MMS) and N-ethyl-N-nitrosourea (ENU), can induce gammaH2AX foci formation in a time- and dose-dependent manner.

Molecular characterization of the cytotoxic mechanism of multiwall carbon nanotubes and nano-onions on human skin fibroblast.

The increasing use of nanotechnology in consumer products and medical applications underlies the importance of understanding its potential toxic effects to people and the environment. Although both fullerene and carbon nanotubes have been demonstrated to accumulate to cytotoxic levels within organs of various animal models and cell types and carbon nanomaterials have been exploited for cancer therapies, the molecular and cellular mechanisms for cytotoxicity of this class of nanomaterial are not yet fully apparent. To address this question, we have performed whole genome expression array analysis and high content image analysis based phenotypic measurements on human skin fibroblast cell populations exposed to multiwall carbon nano-onions (MWCNOs) and multiwall carbon nanotubes (MWCNTs).

A lipidomic study of the effects of N-methyl-N'-nitro-N-nitrosoguanidine on sphingomyelin metabolism.

Systems biology is a new and rapidly developing research area in which, by quantitatively describing the interaction among all the individual components of a cell, a systems-level understanding of a biological response can be achieved. Therefore, it requires high-throughput measurement technologies for biological molecules, such as genomic and proteomic approaches for DNA/RNA and protein, respectively. Recently, a new concept, lipidomics, which utilizes the mass spectrometry (MS) method for lipid analysis, has been proposed.

Sphingolipids are involved in N-methyl-N'-nitro-N-nitrosoguanidine-induced epidermal growth factor receptor clustering.

Previously we have found that N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), an alkylating agent, can induce the clustering of cellular surface receptors including tumor necrosis factor receptor (TNFR) and epidermal growth factor receptor (EGFR). Since sphingolipids, especially ceramide, have been suggested as major players in ligand-induced receptor clustering, their involvement in this ligand-independent, chemical-induced receptor clustering was evaluated. It was shown that MNNG-induced EGFR clustering occurred primarily at lipid rafts, as nystatin, which can disrupt lipid raft structure, significantly decreasing MNNG-induced EGFR clustering.