Optical Methods for Label-Free Detection of Bacteria

Abstract

Pathogenic bacteria are the leading causes of food-borne and water-borne infections, and one of the most serious public threats. Traditional bacterial detection techniques, including plate culture, polymerase chain reaction, and enzyme-linked immunosorbent assay are time-consuming, while hindering precise therapy initiation. Thus, rapid detection of bacteria is of vital clinical importance in reducing the misuse of antibiotics. Among the most recently developed methods, the label-free optical approach is one of the most promising methods that is able to address this challenge due to its rapidity, simplicity, and relatively low-cost. This paper reviews optical methods such as surface-enhanced Raman scattering spectroscopy, surface plasmon resonance, and dark-field microscopic imaging techniques for the rapid detection of pathogenic bacteria in a label-free manner. The advantages and disadvantages of these label-free technologies for bacterial detection are summarized in order to promote their application for rapid bacterial detection in source-limited environments and for drug resistance assessments.

Illuminating the Tiny World: A Navigation Guide for Proper Raman Studies on Microorganisms

“…Since Raman spectroscopy always samples all biomolecules inside the probing volume, most Raman methods are phenotypic which means the information of all biomolecules can be found in the Raman spectra of bacteria [ 15 , 16 , 17 , 18 , 19 ]. In principle, there are two types of Raman measurements of bacteria—bulk samples and single-cell measurements.…”

Absorption/Attenuation Spectral Description of ESKAPEE Bacteria: Application to Seeder-Free Culture Monitoring, Mammalian T-Cell and Bacteria Mixture Analysis and Contamination Description

“…They can be of different types and display a broad spectrum for the detection of any bacteria: (i) antibodies; (ii) aptamers, which have emerged as a good alternative to antibodies since they are cheaper and could target common elements of Gram − or Gram + bacteria [11]; (iii) bacteriophages [12]; (iv) AMPs, which present a strong affinity to bacterial membranes, are stable, easy to produce and store and display a low limit of detection within less than 30 min of incubation [13]; and (v) fluorogenic RNA-cleaving DNAzymes [14], which allow for the detection of 1 bacteria.mL −1 in blood [15]. They could be used in combination with optical methods for the label-free detection of bacteria [16] including SPR, QCM and Raman [17], and these techniques could be developed for online, real-time measurements and integrated into biosensors. Other techniques based on microfluidics (acoustophoresis, microdroplet) and microscopy (reviewed in [7]) are also used for bacteria detection.…”

Fabrication and characterisation of large area, uniform, and controllable surface relief patterns in photopolymer material

“…Qualitative and quantitative analysis of liquid environmental and clinical samples containing bacteria using microbiology methods, such as colony counting, is time-consuming, laborious and require particular skills as well as access to a microbiology lab [1]. Deadly infections caused by bacterial pathogens can be prevented if early and convenient point-ofcare detection is available [2][3][4]. This is particularly important for priority I antibiotic-resistant pathogens (ARP), such as Escherichia coli, for which, according to the World Health Organisation (WHO), the development of new antibiotics is critical [6].…”