Biomimetic NanoVilli Chips for Extracellular Vesicles in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC), the third most common cause of cancer-related deaths worldwide, most often develops in patients with underlying liver cirrhosis or chronic injury secondary to alcohol abuse, nonalcoholic fatty liver disease, or viral hepatitis infections. Cirrhosis from any cause is a well-established risk factor for HCC. The poor prognosis of HCC is due to the fact that diagnosis is often made at a late stage in disease development. The earlier detection of HCC is necessary towards reducing the high HCC mortality rates since those with early stage disease have multiple, potentially curative, treatment options available. However, current surveillance regimens with abdominal imaging and serum biomarkers (e.g., AFP) have poor sensitivity for diagnosing HCC at an early-stage. Therefore, biomarkers that sensitively distinguish early-stage HCC from liver cirrhosis are desperately needed. Extracellular vesicles (EVs) are a heterogeneous group of phospholipid bilayer-enclosed particles known to contain cell-type-specific “cargo,” including RNA, DNA, and protein. Cargo profiling of tumor-derived EVs is an emerging liquid biopsy strategy for non-invasive cancer diagnosis and treatment monitoring. Our joint research team at UCLA has recently developed a new type of “NanoVilli Chip” capable of highly efficient isolation and characterization of tumor-derived EVs from HCC patients. Exploring the use of NanoVilli Chips for cargo profiling of HCC-derived EVs holds great promise as a novel biomarker for detecting early-stage HCC noninvasively. Conventional methods for isolating total EVs, such as ultracentrifugation, filtration, and precipitation, are incapable of discriminating tumor-derived EVs from non-tumor-derived EVs. To address this unmet need, our project team will develop “NanoVilli Chips” based on biomimetic nanostructures and specific immunoaffinity-mediated capturing for HCC-derived EVs. HCC-specific multi-marker capture cocktails (targeting ASGPR, GPC3, and EpCAM) will be grafted onto silicon nanowires (SiNWS) embedded in the chips. When plasma samples approach the SiNWS, specific interactions (between antigens located on the surfaces of tumor-derived EVs and corresponding antibodies grafted on the substrate) lead to selective immobilization of HCC-derived EVs, with dramatically improved sensitivity and specificity. Further, by incorporating Droplet Digital PCR (ddPCR) technology, the HCC-derived EVs captured on the NanoVilli Chips can be characterized by quantifying a panel of 10 well-validated HCC-specific mRNA markers. The proposed research will conduct an exploratory development of NanoVilli Chips for HCC-derived EVs, and an initial clinical validation of NanoVilli Chips using HCC and liver cirrhosis blood samples. Our long-term goal is to explore the use of NanoVilli Chips coated with HCC-associated multi-marker capture cocktails for capturing HCC-derived EVs, allowing for quantification of HCC-specific mRNA signature to augment current HCC early diagnostic algorithms.