Development of a Fully Handmade Paper-based Electrochemical Immunosensor for Detection of Influenza Virus

Abstract

This thesis presents development towards a novel and cost-effective method for the fabrication of a paper-based immunosensing device for the quantitative detection of influenza virus. Use of a paper-based device to electrochemically detect H1N1 virus directly, in an enzyme free approach has not been reported to date and explored for the first time. The construction of the immunosensor essentially consists of two stages; (i) hydrophobization of paper by using a novel and facile technique of spray-coating PDMS-modified silica nanoparticles onto a paper using a glass vaporizer, and (ii) fabrication of electrodes using stencil printing by employing a self-adhesive polyester mask which is very cost-effective and requires minimal instrumentation. Single-walled carbon nanotubes and chitosan modified carbon electrodes are employed to increase the sensitivity and biocompatibility of the sensor, and gluteraldehyde crosslinking is utilized for the immobilization of antibody on the electrode. The device is tested for its sensitivity, in the concentration range from 10 to 104 PFU mL-1 of H1N1 virus and is observed to show linear behavior with the limit of detection 51.284 PFU ml-1. Also, studies are conducted employing MS2 bacteriophages to ensure the selectivity of the device. The immunosensor developed shows specificity to H1N1 virus, indicating almost negligible peak currents for MS2 bacteriophages. To check the behavior of the immunosensor in realistic environment, the virus is suspended in 20% (v/v) saliva with minimal pre-treatment and the analytical performance of the device is quite satisfactory in detecting the virus, although the noise levels seemed to be somewhat higher as also reported in earlier works. With further improvements, this immunosensor is expected to detect virus in real samples (such as saliva, nasal and throat swabs) more effectively and be suitable for clinical diagnosis.