Peptide-activated gold nanoparticles for selective visual sensing of virus

Abstract

In this study, we report peptide-gold nanoparticles (AuNP)-based visual sensor for viruses. Citrate-stabilized AuNP (20 ± 1.9 nm) were functionalized with strong sulfur-gold interface using cysteinylated virus-specific peptide. Peptide-CysAuNP formed complexes with the viruses which made them to aggregate. The aggregation can be observed with naked eye and also with UV-Vis spectrophotometer as a color change from bright red to purple. The test allows for fast and selective detection of specific viruses. Spectroscopic measurements showed high linear correlation (R 2 = 0.995) between the changes in optical density ratio (OD 610 /OD 520 ) with the different concentrations of virus. The new method was compared with the hemagglutinating (HA) test for Newcastle disease virus (NDV). The results indicated that peptide-Cys-AuNP was more sensitive and can visually detect minimum number of virus particles present in the biological samples. The limit of detection for the NDV was 0.125 HA units of the virus. The method allows for selective detection and quantification of the NDV, and requires no isolation of viral RNA and PCR experiments. This strategy may be utilized for detection of other important human and animal viral pathogens.

Role of metal and metal oxide nanoparticles as diagnostic and therapeutic tools for highly prevalent viral infections

“…Further, visual detection by the aggregation of citrate stabilized gold nanoparticles attached to virus particles reveals a much simpler qualitative method for the detection of viruses. Sajjanar et al [87] suggest that gold nanoparticles in the presence of virus particles aggregate and change color from bright red to purple. This method not only enables for the visual detection of the virus, but also quantitatively asses the viral load through simple UV-Visual spectroscopy.…”

“…Here we represent a mechanism by which aggregation of nanoparticles cause the shift in solution color from red to purple due to the presence of virus particles. This method has been followed by many scientists and in detail by Sajjanar et al [87]…”

Colorimetric biosensors for point-of-care virus detections

“…The expensive equipment required includes the thermal cycler, the electrophoresis tank and the UV illuminator [21]. The PCR method of detection is also complex and time consuming, requiring expensive reagents [114]. A key reason for complexity of PCR is due to the thermal cycles required for PCR to take place [54].…”

“…Peptides can be functionalized onto the surface of AuNP for detecting viruses. These AuNPs are bound to cysteinylated virusspecific peptides (peptide-Cys) using the strong sulfur gold bonding [114]. In order for AuNP-peptides to detect the presence of virus, the AuNPs should surround and aggregate around the virus.…”

“…In order for AuNP-peptides to detect the presence of virus, the AuNPs should surround and aggregate around the virus. The peptides used are specially designed and employed as an alternative to antibodies and they offer better affinity to the targeted virus and thus ensuring higher sensitivity [114]. In the presence of the virus, the bioassay changes color from bright red to purple, as AuNP-peptide-virus complex causes aggregation of AuNP around virus, hence the absorption and scattering peaks shift to longer wavelengths [114].…”