A type of biomarkers for prostate cancer, called microRNAs (miRNAs), has a unique level in serum from cancer patients. Hence, detecting them will allow us to diagnose prostate cancer earlier. Currently, this type of biomarkers can only be detected by quantitative real-time polymerase chain reaction. However, this technique does not generate reproducible and reliable results when it is used to detect miRNAs at a low level. To be able to reliably quantify prostate cancer-specific miRNAs at a low level, we propose an ultrasensitive strategy that hires non-toxic virus nanoparticles for probing the miRNAs. This strategy is based on the fact that the virus nanoparticles can be engineered to become capable of emitting three different lights and form complex with nanoparticles for capturing the target miRNAs. It is thus possible to detect multiple target miRNAs in one platform because the virus nanoparticles can emit three different fluorescence lights for detecting three different target miRNAs when three different fluorescent molecules are presented on the surface of the virus nanoparticles. Our objective in this project is to develop the new strategy in order to quantify multiple prostate cancer miRNA biomarkers in serum samples, including three target miRNAs specific for the prostate cancer. We aim to achieve high sensitivity, accuracy, and reproducibility for detecting the prostate cancer biomarkers in serum. This project will develop a new facile method that can precisely detect the prostate cancer biomarkers and thus can be used for early prostate cancer diagnosis.

PUBLIC HEALTH RELEVANCE: This project uses human-safe bacteria-specific virus nanoparticles, gold nanoparticles (GNPs) and magnetic microparticles (MMPs) to detect three miRNA molecules (two are prostate cancer specific and one is general for any cancer). The virus nanoparticles are genetically engineered to become light-emitting and GNP-binding. The GNPs and MMPs are modified with molecules that can bind to different segments of the target miRNA molecules. The GNPs and virus nanoparticles form a GNP/virus complex. In the presence of miRNAs, GNP/virus complex and MMPs form a new complex, where there is one-to-one correspondence between the numbers of virus nanoparticles and miRNA molecules. Because the light-emitting virus nanoparticles can be first released from the complex and then converted into a light-emitting structure called plaque in a one-to-one format when infecting bacteria, counting the number of the plaque can determine the number of cancer biomarker miRNAs, which will in turn be used to diagnose prostate cancer.