Mobile holographic sensor for the detection of herpes simplex virus

A. Ray, M. Daloglu, J. Ho, E. McLeod, A. Ozcan
University of California Los Angeles,
United States

Keywords: virus sensing, mobile microscopy, biosensors

Summary:

Herpes is one of the most common viral infections that has been estimated to have affected >50% of the population between the ages of 14-49 in the United States [1]. It is caused by the HSV-1 and HSV-2 viruses. This infection is easily transmitted by direct contact, through some bodily fluids such as saliva, among others. The virus generally lies dormant in the axons of peripheral nervous system neurons and becomes active during an outbreak. However viral shedding can occur without any symptoms that can lead to unknowingly transmitting the virus. There is a need for new sensors that can rapidly detect the virus and can be used outside clinics. Here we present a mobile optical biosensor, based on computational holographic microscopy, for highly sensitive detection of HSV-1. The virus is first captured selectively using antibodies on a specially prepared glass substrate. These viral particles are then imaged and sized using a field-portable and cost-effective holographic microscope. This microscope consists of 20 different LEDs controlled using a micro-controller, a CMOS imager chip with an active area of 30 sq mm, an optical bandpass filter and a temperature controlled reservoir containing polyethylene glycol (PEG). The temperature controlled reservoir is used to heat up the PEG which vaporizes and gets deposited on the substrate to create self-assembled nano-droplets around the sample, which act as nanolenses. The substrate is placed on a sample holder and illuminated from the bottom. The interference between the waves scattered by the sample and the directly transmitted light is recorded on the CMOS imager placed close to the sample (