Nanomaterial Interactions with Human Neutrophils.

Neutrophils are the most abundant circulating leukocyte and the first point of contact between many drug delivery formulations and human cells. Despite their prevalence and implication in a range of immune functions, little is known about how human neutrophils respond to synthetic particulates. Here, we describe how ex vivo human neutrophils respond to particles which vary in both size (5 nm to 2 µm) and chemistry (lipids, poly(styrene), poly(lactic-co-glycolic acid), and gold). In particular, we show that (i) particle uptake is rapid, typically plateauing within 15 min; (ii) for a given particle chemistry, neutrophils preferentially take up larger particles at the nanoscale, up to 200 nm in size; (iii) uptake of nanoscale poly(styrene) and liposomal particles at concentrations of up to 5 µg/mL does not enhance apoptosis, activation, or cell death; (iv) particle-laden neutrophils retain the ability to degranulate normally in response to chemical stimulation; and (v) ingested particles reside in intracellular compartments that are retained during activation and degranulation. Aside from the implications for design of intravenously delivered particulate formulations in general, we expect these observations to be of particular use for targeting nanoparticles to circulating neutrophils, their clearance site (bone marrow), or distal sites of active inflammation.

Molecular Rotors for Universal Quantitation of Nanoscale Hydrophobic Interfaces in Microplate Format.

Hydrophobic self-assembly pairs diverse chemical precursors and simple formulation processes to access a vast array of functional colloids. Exploration of this design space, however, is stymied by lack of broadly general, high-throughput colloid characterization tools. Here, we show that a narrow structural subset of fluorescent, zwitterionic molecular rotors, dialkylaminostilbazolium sulfonates [DASS] with intermediate-length alkyl tails, fills this major analytical void by quantitatively sensing hydrophobic interfaces in microplate format. DASS dyes supersede existing interfacial probes by avoiding off-target fluorogenic interactions and dye aggregation while preserving hydrophobic partitioning strength. To illustrate the generality of this approach, we demonstrate (i) a microplate-based technique for measuring mass concentration of small (20-200 nm), dilute (submicrogram sensitivity) drug delivery nanoparticles; (ii) elimination of particle size, surfactant chemistry, and throughput constraints on quantifying the complex surfactant/metal oxide adsorption isotherms critical for environmental remediation and enhanced oil recovery; and (iii) more reliable self-assembly onset quantitation for chemically and structurally distinct amphiphiles. These methods could streamline the development of nanotechnologies for a broad range of applications.

Universal process-inert encoding architecture for polymer microparticles.

Polymer microparticles with unique, decodable identities are versatile information carriers with a small footprint. Widespread incorporation into industrial processes, however, is limited by a trade-off between encoding density, scalability and decoding robustness in diverse physicochemical environments. Here, we report an encoding strategy that combines spatial patterning with rare-earth upconversion nanocrystals, single-wavelength near-infrared excitation and portable CCD (charge-coupled device)-based decoding to distinguish particles synthesized by means of flow lithography. This architecture exhibits large, exponentially scalable encoding capacities (>10(6) particles), an ultralow decoding false-alarm rate (<10(-9)), the ability to manipulate particles by applying magnetic fields, and pronounced insensitivity to both particle chemistry and harsh processing conditions. We demonstrate quantitative agreement between observed and predicted decoding for a range of practical applications with orthogonal requirements, including covert multiparticle barcoding of pharmaceutical packaging (refractive-index matching), multiplexed microRNA detection (biocompatibility) and embedded labelling of high-temperature-cast objects (temperature resistance).

Notch-dependent induction of left/right asymmetry in C. elegans interneurons and motoneurons.

Although nervous systems are largely bilaterally symmetric on a structural level, they display striking degrees of functional left/right (L/R) asymmetry. In Caenorhabditis elegans, two structurally symmetric pairs of sensory neurons, ASE and AWC, display two distinctly controlled types of functional L/R asymmetries (stereotyped versus stochastic asymmetry). Beyond these two cases, the extent of neuronal asymmetry in the C. elegans nervous system was unclear. Here, we report that the Beta3/Olig-type bHLH transcription factor hlh-16 is L/R asymmetrically expressed in several distinct, otherwise bilaterally symmetric interneuron and motoneuron pairs that are part of a known navigation circuit. We find that hlh-16 asymmetry is generated during gastrulation by an asymmetric LAG-2/Delta signal originating from the mesoderm that promotes hlh-16 expression in neurons on the left side through direct binding of the Notch effector LAG-1/Su(H)/CBF to a cis-regulatory element in the hlh-16 locus. Removal of hlh-16 reveals an unanticipated asymmetry in the ability of the axons of the AIY interneurons to extend into the nerve ring, with the left AIY axon requiring elevated hlh-16 expression for correct extension. Our study suggests that the extent of molecular L/R asymmetry in the C. elegans nervous system is broader than previously anticipated, establishes a novel signaling mechanism that crosses germ layers to diversify bilaterally symmetric neuronal lineages, and reveals L/R asymmetric control of axonal outgrowth of bilaterally symmetric neurons.

Novel pentablock copolymers for selective gene delivery to cancer cells.

PURPOSE: In this study, the novel poly(diethylaminoethylmethacrylate) (PDEAEM)/Pluronic F127 pentablock copolymers were found to be able to mediate high-efficiency transfection of human epithelial ovarian carcinoma (SKOV3) cell line while showing significantly lower efficacy in human epithelial retinal (ARPE-19) cell line and Swiss Mouse Fibroblast (3T3) cell line. METHODS: The intracellular routes of polyplexes were investigated by confocal microscopy after appropriately labeling the polymer and DNA. RESULTS: It was found that lesser nuclear entry in the ARPE-19 cells may result in the lower efficiency of transfection. Since the SKOV3 proliferation rate was found to be much higher than that of the ARPE-19 cells, the nuclear entry of polyplexes was assumed to be correlated with the proliferation rate, and it was hypothesized that the novel pentablock copolymers could mediate gene delivery selectively in fast growing cells. The different intracellular barriers to gene transfer may also account for the observed difference of transfection efficacy. CONCLUSIONS: Although the validity of the hypothesis that our pentablock copolymer could selectively transfect hyperproliferative cells needs further examination, this present work provides a new perspective to design targeting vectors for cancer therapies based on different characteristics among specific cell types.