Ultrasensitive multiplex optical quantification of bacteria in large samples of biofluids

Identifier:  PC:1784

Handle: https://hdl.handle.net/20.500.11797/PC1784

Authors:  Ramon A. Alvarez-Puebla; Nicolas Pazos-Perez; Elena Pazos; Carme Catala; Bernat Mir-Simon; Sara Gómez-de Pedro; Juan Sagales; Carlos Villanueva; Jordi Vila; Alex Soriano; F. Javier García de Abajo

Abstract:
Efficient treatments in bacterial infections require the fast and accurate recognition of pathogens, with concentrations as low as one per milliliter in the case of septicemia. Detecting and quantifying bacteria in such low concentrations is challenging and typically demands cultures of large samples of blood (∼1 milliliter) extending over 24-72 hours. This delay seriously compromises the health of patients. Here we demonstrate a fast microorganism optical detection system for the exhaustive identification and quantification of pathogens in volumes of biofluids with clinical relevance (∼1 milliliter) in minutes. We drive each type of bacteria to accumulate antibody functionalized SERS-labelled silver nanoparticles. Particle aggregation on the bacteria membranes renders dense arrays of inter-particle gaps in which the Raman signal is exponentially amplified by several orders of magnitude relative to the dispersed particles. This enables a multiplex identification of the microorganisms through the molecule-specific spectral fingerprints.