Differential Mobility Spectrometry for Inorganic Filtration in Nuclear Forensics.

Differential mobility spectrometry (DMS) is applied to the analysis of inorganic mixtures relevant to nuclear forensics. Three primary components of potential radiological dispersal devices (RDDs), cobalt, cesium, and strontium, were studied by DMS to demonstrate rapid sample cleanup when coupled to mass spectrometry. Nanosprayed salt solutions comprised of stable analogs, as proxies to these radioisotopes, and isobaric interferents were introduced to DMS. The DMS effluent was directly coupled to a mass spectrometer to confirm the elemental identity of the separated clusters. DMS dispersion plots demonstrated distinctive elemental separation from both atomic and molecular interferents. These results support the potential use of DMS as a means of rapid separation for inorganic analyses prior to analysis in a field portable mass spectrometer. The mechanism for this process is speculated to involve dynamics of solvent cluster formation under the influence of the alternating high and low electric fields of the DMS.

Heparin octasaccharide decoy liposomes inhibit replication of multiple viruses.

Heparan sulfate (HS) is a ubiquitous glycosaminoglycan that serves as a cellular attachment site for a number of significant human pathogens, including respiratory syncytial virus (RSV), human parainfluenza virus 3 (hPIV3), and herpes simplex virus (HSV). Decoy receptors can target pathogens by binding to the receptor pocket on viral attachment proteins, acting as 'molecular sinks' and preventing the pathogen from binding to susceptible host cells. Decoy receptors functionalized with HS could bind to pathogens and prevent infection, so we generated decoy liposomes displaying HS-octasaccharide (HS-octa). These decoy liposomes significantly inhibited RSV, hPIV3, and HSV infectivity in vitro to a greater degree than the original HS-octa building block. The degree of inhibition correlated with the density of HS-octa displayed on the liposome surface. Decoy liposomes with HS-octa inhibited infection of viruses to a greater extent than either full-length heparin or HS-octa alone. Decoy liposomes were effective when added prior to infection or following the initial infection of cells in vitro. By targeting the well-conserved receptor-binding sites of HS-binding viruses, decoy liposomes functionalized with HS-octa are a promising therapeutic antiviral agent and illustrate the utility of the liposome delivery platform.

Enhanced delivery of topically-applied formulations following skin pre-treatment with a hand-applied, plastic microneedle array.

The purpose of this work is to characterize microchannels created by polymeric microneedles, applied by hand, and to demonstrate enhanced delivery of topically applied formulations of lidocaine hydrochloride and methylprednisolone sodium succinate (MPSS). 3M's Microstructured Transdermal System (MTS) arrays were applied to domestic swine to demonstrate reliability of penetration, depth of penetration and durability of the structures to repeat application and high force. Tissue levels of lidocaine and MPSS following topical application with and without microneedle pretreatment were determined by HPLC-MS analysis following digestion of biopsies. Almost all microneedles penetrate the stratum corneum upon hand force application. The depth of penetration varies from <100µm to nearly 150µm depending on the application force and the firmness of the underlying tissue. The arrays show excellent durability to repeated in-vivo application, with less than 5% of the structures evidencing even minimal tip bending after 16 applications. Under extreme force against a rigid surface, the microneedles bend but do not break. A lidocaine hydrochloride formulation applied topically in-vivo showed ~340% increase in local tissue levels when the MTS arrays were used to twice pre-treat the skin prior to applying the drug. Local delivery of a topically applied formulation of MPSS was over one order of magnitude higher when the application site was twice pre-treated with the MTS array. 3M's MTS array (marketed as 3M(TM) Microchannel Skin System) provides repeatable and robust penetration of the stratum corneum and epidermis and enhances delivery of some formulations such as lidocaine hydrochloride.