Nitric Oxide-Releasing Xerogels Synthesized from N -Diazeniumdiolate-Modified Silane Precursors

Nitric oxide (NO)-releasing xerogel materials were synthesized using N-diazeniumdiolate-modified silane monomers that were subsequently co-condensed with an alkoxysilane. The NO-release characteristics were tuned by varying the aminosilane structure and concentration. The resulting materials exhibited maximum NO release totals and durations ranging from 0.45–3.2 µmol cm−2 and 20–90 h, respectively. The stability of the xerogel networks was optimized by varying the alkoxysilane backbone identity, water to silane ratio, base catalyst concentration, reaction time, and drying conditions. The response of glucose biosensors prepared using the NO-releasing xerogel (15 mol% N-diazeniumdiolate-modified N-2-(aminoethyl)-aminopropyltrimethoxysilane) as an outer sensor membrane was linear (R2 = .979) up to 24 mM glucose. The sensitivity (3.4 nA mM−1) of the device to glucose was maintained for 7 d in phosphate buffered saline. The facile sol-gel synthetic route, along with the NO release and glucose biosensor characteristics, demonstrates the versatility of this method for biosensor membrane applications

Local delivery of nitric oxide: Targeted delivery of therapeutics to bone and connective tissues

Non-invasive treatment of injuries and disorders affecting bones and connective tissue is a significant challenge facing the medical community. A treatment route that has recently been proposed is nitric oxide (NO) therapy. Nitric oxide plays several roles in physiology with many conditions lacking adequate levels of NO. As NO is a radical, localized delivery via NO donors is essential to promoting biological activity. Herein, we review current literature related to therapeutic NO delivery in the treatment of bone, skin and tendon repair

Inaccuracies of Nitric Oxide Measurement Methods in Biological Media

Despite growing reports on the biological action of nitric oxide (NO) as a function of NO payload, the validity of such work is often questionable due to the manner in which NO is measured and/or the solution composition in which NO is quantified. To highlight the importance of measurement technique for a given sample type, NO produced from a small molecule NO donor (N-diazeniumdiolated l-proline, PROLI/NO) and a NO-releasing xerogel film were quantified in a number of physiological buffers and fluids, cell culture media, and bacterial broth using the Griess assay, a chemiluminescence analyzer, and an amperometric NO sensor. Despite widespread use, the Griess assay proved to be inaccurate for measuring NO in many of the media tested. In contrast, the chemiluminescence analyzer provided superb kinetic information in most buffers, but was impractical for NO analysis in proteinaceous media. The electrochemical NO sensor enabled greater flexibility across the various media with potential for spatial resolution, albeit at lower than expected NO totals versus either the Griess assay or chemiluminescence. The results of this study highlight the importance of measurement strategy for accurate NO analysis and reporting NO-based biological activity

South African Ebola diagnostic response in Sierra Leone : a modular high biosafety field laboratory

BACKGROUND : In August 2014, the National Institute for Communicable Diseases (NICD) in South Africa established a modular high-biosafety field Ebola diagnostic laboratory (SA FEDL) near Freetown, Sierra Leone in response to the rapidly increasing number of Ebola virus disease (EVD) cases. METHODS AND FINDINGS : The SA FEDL operated in the Western Area of Sierra Leone, which remained a ªhotspotº of the EVD epidemic for months. The FEDL was the only diagnostic capacity available to respond to the overwhelming demand for rapid EVD laboratory diagnosis for several weeks in the initial stages of the EVD crisis in the capital of Sierra Leone. Furthermore, the NICD set out to establish local capacity amongst Sierra Leonean nationals in all aspects of the FEDL functions from the outset. This led to the successful hand-over of the FEDL to the Sierra Leone Ministry of Health and Sanitation in March 2015. Between 25 August 2014 and 22 June 2016, the laboratory tested 11,250 specimens mostly from the Western Urban and Western Rural regions of Sierra Leone, of which 2,379 (21.14%) tested positive for Ebola virus RNA. CONCLUSIONS : he bio-safety standards and the portability of the SA FEDL, offered a cost-effective and practical alternative for the rapid deployment of a field-operated high biocontainment facility. The SA FEDL teams demonstrated that it is highly beneficial to train the national staff in the course of formidable disease outbreak and accomplished their full integration into all operational and diagnostic aspects of the laboratory. This initiative contributed to the international efforts in bringing the EVD outbreak under control in Sierra Leone, as well as capacitating local African scientists and technologists to respond to diagnostic needs that might be required in future outbreaks of highly contagious pathogens.S1 Video. ªHotº processing of Ebola clinical specimens, PPE and decontamination procedures in South African modular, field-operated biocontainment facility in Sierra Leone.Janusz T Paweska was supported by funding from National Research Foundation and the Global Disease Detection Programmehttp://www.plosntds.orgam2017Microbiology and Plant Patholog

Inaccuracies of Nitric Oxide Measurement Methods in Biological Media

Despite growing reports on the biological action of nitric oxide (NO) as a function of NO payload, the validity of such work is often questionable due to the manner in which NO is measured and/or the solution composition in which NO is quantified. To highlight the importance of measurement technique for a given sample type, NO produced from a small-molecule NO donor (<i>N</i>-diazeniumdiolated l-proline, PROLI/NO) and a NO-releasing xerogel film were quantified in a number of physiological buffers and fluids, cell culture media, and bacterial broth by the Griess assay, a chemiluminescence analyzer, and an amperometric NO sensor. Despite widespread use, the Griess assay proved to be inaccurate for measuring NO in many of the media tested. In contrast, the chemiluminescence analyzer provided superb kinetic information in most buffers but was impractical for NO analysis in proteinaceous media. The electrochemical NO sensor enabled greater flexibility across the various media with potential for spatial resolution, albeit at lower than expected NO totals versus either the Griess assay or chemiluminescence. The results of this study highlight the importance of measurement strategy for accurate NO analysis and reporting NO-based biological activity

Number of specimens from EVD suspected cases in Sierra Leone tested daily (total blood and buccal swabs) by SA FEDL during the first weeks of operation, 25 August—30 Sept 2014.

<p>Column = Number of specimens tested daily; Dotted line = Trend line of a number of specimens tested; Solid line = Maximum testing capacity of 58 specimens per day.</p

Layout of the SA FEDL in Freetown-Lakka, Sierra Leone with emergency generator and wiring to allow for rapid switch to generator mode in case of power failure.

<p>(<b>A</b>) Biocontainment negative pressure chamber (IsoArk), (<b>B</b>) Room housing biocontainment negative pressure chamber, (<b>C</b>) Donning room, (<b>D</b>) Doffing room, (<b>E</b>) Laboratory airlock area, (<b>F</b>) PCR amplification room, (<b>G</b>) PCR master mix room, (<b>H</b>) Specimens and reagents storage area, (<b>I</b>) RNA extraction room, (<b>J</b>) Facility entrance, (<b>K</b>) Toilet, (<b>L</b>) Office 1, (<b>M</b>) Office 2, (<b>N</b>) Office 3. Petrol generator (5.5 kVa) placement indicated by the red rectangle, distribution of extension cords are indicated with red lines, and emergency connection points by red stars.</p

South African Ebola diagnostic response in Sierra Leone: A modular high biosafety field laboratory - Fig 3

<p>(<b>A</b>) Operators dressed in BSL3 PPE processing clinical specimens from EVD suspected cases in a glovebox located within the IsoArk biocontainment negative pressure chamber, (<b>B</b>) Blood tubes in centrifuge adapters with safety caps passed into the main chamber of the glovebox for “hot” inactivation and aliquoting for long-term storage.</p

Ebola virus polymerase gene TaqMan real-time RT-PCR results in blood specimens.

<p>Ebola virus polymerase gene TaqMan real-time RT-PCR results in blood specimens.</p