Nanoplasmonic Decoration of Sacrificial Bacteria: Directing Interparticle Coupling Toward Multiplex Analysis of Antiseptic Alcohols

Engineeringinterparticle plasmon coupling through controllingthe assembly of plasmonic NPs onto the surface of sacrificial substratesis quite promising for establishing inherently absent selectivityor sensitivity toward a particular analyte. Herein, we introduce arobust sensor array strategy based upon the assembly of gold nanoparticles(AuNPs) on the cysteamine-modified surface of two Gram-positive probioticbacteria, i.e., Lactobacillus reuteri (LBR) and Bifidobacterium lactis (BFL), as potential sacrificial substrates,for discrimination and quantification of antiseptic alcohols (AAs)comprising methanol, ethanol, and isopropanol. In fact, the damageof the bacterial membrane upon exposure to the foregoing alcoholsinhibits the assembly of AuNPs, thereby precluding color variationsfrom red to blue. Unequal resistance of the bacterial membranes againstdamage by the alcohols underlies independent response patterns foreach analyte. The supervised classification of visible spectra andRGB data by Linear Discriminant Analysis (LDA) revealed the remarkablepotential of the designed sensor array in differentiating single-componentand multicomponent samples of AAs. Moreover, the Partial Least SquareRegression (PLSR) technique exhibited excellent applicability to multivariatecalibration of both spectral and RGB data. The intriguing attributesof the implemented approach not only hold great potential in the authenticationand quality assessment of alcohol-based products but open up a newprospect for deployment of sacrificial substrates in the design ofinterparticle coupling-based sensors.

Automated summary

Engineering interparticle plasmon coupling through controlling the assembly of plasmonic nanoparticles on the surface of sacrificial substrates shows great potential for selective and sensitive detection of specific analytes.