Biosensors & bioelectronics
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Biosens Bioelectron · Feb 2017
Comparative StudyComparison of optomagnetic and AC susceptibility readouts in a magnetic nanoparticle agglutination assay for detection of C-reactive protein.
There is an increasing need to develop biosensor methods that are highly sensitive and that can be combined with low-cost consumables. The use of magnetic nanoparticles (MNPs) is attractive because their detection is compatible with low-cost disposables and because application of a magnetic field can be used to accelerate assay kinetics. We present the first study and comparison of the performance of magnetic susceptibility measurements and a newly proposed optomagnetic method. ⋯ The two techniques provided highly correlated results upon agglutination when they measure the decrease of the signal from the individual MNPs (turn-off detection strategy), whereas the techniques provided different results, strongly depending on the read-out frequency, when detecting the signal due to MNP agglomerates (turn-on detection strategy). These observations are considered to be caused by differences in the volume-dependence of the magnetic and optical signals from agglomerates. The highest signal from agglomerates was found in the optomagnetic signal at low frequencies.
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Biosens Bioelectron · Jan 2016
ReviewTowards detection and diagnosis of Ebola virus disease at point-of-care.
Ebola outbreak-2014 (mainly Zaire strain related Ebola virus) has been declared most widely spread deadly persistent epidemic due to unavailability of rapid diagnostic, detection, and therapeutics. Ebola virus disease (EVD), a severe viral hemorrhagic fever syndrome caused by Ebola virus (EBOV) is transmitted by direct contact with the body fluids of infected person and objects contaminated with virus or infected animals. World Health Organization (WHO) has declared EVD epidemic as public health emergency of international concern with severe global economic burden. ⋯ Thus developing a cost-effective, rapid, sensitive, and selective sensor to detect EVD at point-of-care (POC) is certainly worth exploring to establish rapid diagnostics to decide therapeutics. This review highlights SoA of Ebola diagnostics and also a call to develop rapid, selective and sensitive POC detection of EBOV for global health care. We propose that adopting miniaturized electrochemical EBOV immunosensing can detect virus level at pM concentration within ∼40min compared to 3 days of ELISA test at nM levels.
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Biosens Bioelectron · Dec 2015
Capillary-scale direct measurement of hemoglobin concentration of erythrocytes using photothermal angular light scattering.
We present a direct, rapid and chemical-free detection method for hemoglobin concentration ([Hb]), based on photothermal angular light scattering. The iron oxides contained in hemoglobin molecules exhibit high absorption of 532-nm light and generate heat under the illumination of 532-nm light, which subsequently alters the refractive index of blood. ⋯ Our system measured [Hb] over the range of 0.35-17.9 g/dL with a detection limit of ~0.12 g/dL. Our sensor was characterized by excellent correlation with a reference hematology analyzer (r>0.96), and yielded a precision of 0.63 g/dL for a blood sample of 9.0 g/dL.
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Biosens Bioelectron · May 2015
A true theranostic approach to medicine: towards tandem sensor detection and removal of endotoxin in blood.
Sepsis is one of the leading causes of death around the world. The condition occurs when a local infection overcomes the host natural defense mechanism and suddenly spreads into the circulatory system, triggering a vigorous, self-injurious inflammatory host response. The pathogenesis of sepsis is relatively well known, one of the most potent immuno-activator being bacterial lipopolysaccharide (LPS) - also known as 'endotoxin'. ⋯ Analogous surface modification is used on glass beads for the therapeutic cartridge component of the combined strategy. Incubation of LPS-spiked whole blood with PMB-bead chemistry resulted in a significant decrease in the production of pro-inflammatory TNF-α cytokine. LPS neutralization is discussed in relation to the perturbation of its supramolecular chemistry in solution.
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Biosens Bioelectron · Sep 2014
Total internal reflection (TIRF)-based quantification of procalcitonin for sepsis diagnosis--a point-of-care testing application.
A new, highly sensitive fluorescence immunoassay for a TIRF (total internal reflection)-based point-of-care testing (POCT) device was developed for the detection of procalcitonin (PCT), a specific and early marker for sepsis and microbial infections. The immunoassay was performed on a bench-top system that fulfilled all the necessary characteristics of a POCT application, including a short measurement time (<9 min), no sample pre-treatment requirements and application directly near patients. New rat monoclonal antibodies targeting PCT were screened and characterized. ⋯ Furthermore, the developed PCT assay can be applied in whole human blood with an adequate sensitivity (LOD=0.02 ng/mL; LOQ=0.09 ng/mL). To the best of our knowledge, this is the first diagnostic test for sepsis to use whole blood, which is a crucial requirement for POCT. We were able to detect native PCT in patient samples and showed a good correlation (R(2)=0.988) with the results of the Kryptor(®) device from BRAHMS, a state of the art device for the detection of PCT.