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Heterogeneous endotoxin detection bioassay using drug–nanoparticle bioconjugates: an optimization study

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Abstract

We present a detailed study of an endotoxin detection bioassay performed in a sandwich format on solid substrates. Self-assembled monolayers (SAMs) of C-18 alkyl silanes were immobilized on glass to heterogeneously entrap lipopolysaccharides (LPS) from human serum. The captured endotoxin was then tagged with polymyxin B sulfate–gold nanoparticle (GNP) conjugates followed by silver enhancement. The intensity of the obtained color spots were quantified using a mobile phone camera and the assay performance was optimized by studying the effects of various experimental parameters like silane concentration, temperature, humidity and incubation time. The assay gave a linear dynamic range of 104 with a lower limit of detection (LOD) at 1 pg mL−1. This LOD was further improved by an LPS pre-enrichment step prior to the assay. Rudimentary thermodynamic and kinetic models fitted to our experimental data suggest that LPS binding is an entropic process and LPS/GNP binding is mainly adsorption-controlled.

Graphical abstract: Heterogeneous endotoxin detection bioassay using drug–nanoparticle bioconjugates: an optimization study

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Publication details

The article was received on 24 May 2017, accepted on 25 Jul 2017 and first published on 25 Jul 2017


Article type: Paper
DOI: 10.1039/C7ME00037E
Citation: Mol. Syst. Des. Eng., 2017, Advance Article
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    Heterogeneous endotoxin detection bioassay using drug–nanoparticle bioconjugates: an optimization study

    P. Kalita, A. Bhola, N. Goel, V. Sritharan and S. Gupta, Mol. Syst. Des. Eng., 2017, Advance Article , DOI: 10.1039/C7ME00037E

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