Label-Free Darkfield-Based Technique to Assist in the Detection of Giardia Cysts

Belini, Valdinei Luís; Freitas, Bárbara Luíza Souza; Sabogal-Paz, Lyda Patrícia; Branco, Nilson; Franco, Regina Maura Bueno

doi:10.1007/s11270-018-3834-x

Cited by 7 publications

(10 citation statements)

References 17 publications

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“…The annular beam formed by the incident light turns into a hollow conical beam after the light is concentrated through the condenser, and illuminates the sample, thus stimulating the scattering of sample particles. In this setting, only scattering light from objects in the medium enters the objective lens, creating a bright scattering pattern in a dark background [ 102 ]. Due to the Tyndall effect, particles far below the resolution limit of typical light microscopes can be observed using dark-field microscopes [ 103 ].…”

Section: Label-free Detection Of Bacteria By Dark-field Microscopymentioning

confidence: 99%

“…Dark-field microscopy is an interesting optical technique that has been successfully used to image bacteria [ 40 , 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 , 113 , 114 ] and protozoa [ 102 , 115 ] due to its very low background, simple construction, portability, and low cost. Since plasma nanoparticles exhibit strong scattering to visible light, dark-field microscopy is a powerful tool for imaging and localization of noble metal nanoparticles in single cell analysis [ 101 , 109 , 116 , 117 ].…”

Section: Label-free Detection Of Bacteria By Dark-field Microscopymentioning

confidence: 99%

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Optical Methods for Label-Free Detection of Bacteria

et al. 2022

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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.

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Section: Label-free Detection Of Bacteria By Dark-field Microscopymentioning

confidence: 99%

Section: Label-free Detection Of Bacteria By Dark-field Microscopymentioning

confidence: 99%

Optical Methods for Label-Free Detection of Bacteria

et al. 2022

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“…1), 15 which considerably lowers the number photons received by individual cells. 16 Previous studies utilized DM to image simple life forms, such as bacteria and protozoa, [17][18][19][20] which grow well in open air and at ambient temperature. 19,20 No DM imaging has been performed on light-sensitive mammalian cells, which requires well-controlled experimental conditions, i.e., 37 C, 5% CO 2 and 100% RH.…”

Section: Introductionmentioning

confidence: 99%

“…16 Previous studies utilized DM to image simple life forms, such as bacteria and protozoa, [17][18][19][20] which grow well in open air and at ambient temperature. 19,20 No DM imaging has been performed on light-sensitive mammalian cells, which requires well-controlled experimental conditions, i.e., 37 C, 5% CO 2 and 100% RH. 21,22 In this study, we describe a live cell DM imaging platform with well-maintained culture conditions (Fig.…”

Section: Introductionmentioning

confidence: 99%

Continuous live cell imaging using dark field microscopy

et al. 2022

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“…Dark field (DF) microscopy is an interesting, easy, and inexpensive alternative visualization technique to image unstained specimens. This technique has been successfully used to image bacteria [7] and protozoa [8]. DF microscopes have the advantage to be rather simple and cost effective with the good potential of portability [9].…”

Section: Introductionmentioning

confidence: 99%

Dark Field Microscopy-Based Biosensors for the Detection of E. coli in Environmental Water Samples

Spina

António

Desmet

et al. 2019

Sensors

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Development of sensitive methods for the determination of E. coli bacteria contamination in water distribution systems is of paramount importance to ensure the microbial safety of drinking water. This work presents a new sensing platform enabling the fast detection of bacteria in field samples by using specific antibodies as the biorecognition element and dark field microscopy as the detection technique. The development of the sensing platform was performed using non-pathogenic bacteria, with the E. coli DH5α strain as the target, and Bacillus sp. 9727 as the negative control. The identification of the captured bacteria was made by analyzing the dark field microscopy images and screening the detected objects by using object circularity and size parameters. Specificity tests revealed the low unspecific attachment of either E. coli over human serum albumin antibodies (negative control for antibody specificity) and of Bacillus sp. over E. coli antibodies. The system performance was tested using field samples, collected from a wastewater treatment plant, and compared with two quantification techniques (i.e., Colilert-18 test and quantitative polymerase chain reaction (qPCR)). The results showed comparable quantification capability. Nevertheless, the present method has the advantage of being faster, is easily adaptable to in-field analysis, and can potentially be extended to the detection of other bacterial strains.

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Label-Free Darkfield-Based Technique to Assist in the Detection of Giardia Cysts

Cited by 7 publications

References 17 publications

Optical Methods for Label-Free Detection of Bacteria

Optical Methods for Label-Free Detection of Bacteria

Continuous live cell imaging using dark field microscopy

Dark Field Microscopy-Based Biosensors for the Detection of E. coli in Environmental Water Samples

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