Abstract
The development of a biosensor for rapid and quantitative detection of the dengue virus continues to remain a challenge. We report a lab-on-chip device that combines membrane-based blood plasma separation and a localized surface plasmon resonance (LSPR) based biosensor for on-chip detection of dengue NS1 antigen from a few drops of blood. The LSPR effect is realized by irradiating UV-NIR light having a spectral peak at 655 nm onto nanostructures fabricated via thermal annealing of a thin metal film. We study the effect of the resulting metal nanostructures on the LSPR performance in terms of sensitivity and limit of detection, by annealing silver films at temperatures ranging from 100 to 500 °C. The effect of annealing temperature on the nanostructure size and uniformity and the resulting optical characteristics are investigated. Further, the binding between non-targeted blood plasma proteins and NS1-antibody-functionalized nanostructures on the LSPR performance is studied by considering different blocking mechanisms. Using a nanostructure annealed at 200 °C and 2X-phosphate buffer saline with 0.05% Tween-20 as the blocking buffer, from 10 μL of whole blood, the device can detect NS1 antigen at a concentration as low as 0.047 μg mL−1 within 30 min. Finally, we demonstrate the detection of NS1 in the blood samples of dengue-infected patients and validate our results with those obtained from the gold-standard ELISA test.
Highlights
Dengue is a vector-borne viral disease caused by the dengue virus (DENV) which infects hundreds of millions of people every year in more than a hundred countries.[1]
We investigate the binding between non-targeted blood-plasma proteins with NS1-antibodyfunctionalized nanostructures on the localized surface plasmon resonance (LSPR) performance by considering different blocking mechanisms
Based on the above studies, we develop an improved lab-on-chip device that combines membrane-based blood plasma separation and a biosensor based on localized surface plasmon resonance (LSPR) for on-chip detection of dengue NS1 antigen from a few drops of blood
Summary
Dengue is a vector-borne viral disease caused by the dengue virus (DENV) which infects hundreds of millions of people every year in more than a hundred countries.[1]. To achieve detection speed comparable to that of RDTs without compromising on the accuracy and sensitivity, micro uidics-based biosensors have been developed for dengue detection.[8,9,10] The inherent limitations of electrical and electrochemical sensing mechanisms[8,9] in terms of pH dependency and reproducibility are overcome by optical techniques.[10] Recently, highly sensitive optical detection techniques such as localized surface plasmon resonance (LSPR)[11] have been developed for dengue detection Plasmonic metal nanoparticles such as gold and silver have drawn signi cant attention from researchers in recent decades due to their unique optical, electromagnetic, chemical, and biological properties.[12,13,14] Extensive study of silver nanoparticles have been carried out owing to their unique optical properties, that can be utilized to develop nanoscale optical, chemical, and biological sensors.[12] FTIR spectrum of silver nanoparticles has shown a strong interaction between different functional groups and silver surfaces.[13] gold nanoparticles are popular for biosensing applications owing to their ease of preparation, biocompatibility, and inertness.[14] Even though gold nanoparticles are preferred due to their biocompatibility and chemical stability, silver nanoparticles offer better sensitivity and a broad absorption spectrum (300–1200 nm).[15] The wide absorption spectrum is attributed to the LSPR. The detection of dengue NS1 antigens in the blood samples of dengue infected patients is demonstrated and our results are compared with that obtained from the conventional ELISA test
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