UC Riverside

Since 1970, human activities have permitted the spread of Dengue virus (DENV) and the primary mosquito vectors Aedes spp. to virtually every continent. Infection rates have increased more than 30-fold and it has become the most prevalent arboviral disease in the world. Every year, 3.6 billion people are at risk of infection and there are 390 million new infections, mostly among children. With no vaccine or specific treatment, early detection plays a significant role in decreasing fatality rates. Dengue infection has no pathognomonic clinical features, thus diagnostic tools are essential for diagnosis.

In addition to a human transmission cycle, a variety of forest-dwelling non-human primates are hosts for DENV in a sylvatic cycle. Unfortunately, sylvatic cross-over events occur regularly and have resulted in disease outbreaks within humans. Vector surveillance plays a critical role in dengue detection and outbreak prevention. Current laboratory methods for detection and diagnosis of DENV require highly trained personnel and costly equipment that are impractical for regular surveillance and diagnostic use.

Thus, new technologies to facilitate and enhance diagnostic and surveillance capabilities within each transmission cycle are urgently needed. This research describes the development of two novel biosensors using single-walled carbon nanotube transducers functionalized for the detection of whole DENV or DENV Non-Structural Protein 1 (NS1). Heparin, an analog of the heparan sulfate proteoglycans that are receptors for DENV, was used as a bioreceptor for detection of whole DENV virions within viral culture. This permits detection of DENV virions from a variety of viral culture-compatible samples; such as fluid or tissue samples from monkeys, vector mosquitos, and humans. Anti-dengue NS1 monoclonal antibodies were used to detect DENV NS1, a clinically accepted biomarker for DENV infection. This biosensor will allow early detection and diagnosis of the disease in Aedes mosquitos and human saliva. Both biosensors were selective and sensitive for their target analyte in a 10-μL sample over the clinically relevant concentration range with detection occurring in only 10-20 min. Each was constructed to be a portable, rapid, and inexpensive diagnostic tool suitable for use by minimally-trained personnel in the field, laboratory, or point-of-care location.