Abstract 5540: Digital nanoneedle biosensors enable comprehensive monitoring of systemic inflammatory response to immunotherapies
Authors: Quan Qimin , Ritchey Joshua , Clenow Mark , Wilkinson Joe , Geanacopoulos John , Boyce John 
Published: September 2020

Abstract
Cytokine release syndrome (CRS), a systemic inflammatory response observed in some monoclonal antibody drugs and adaptive T-Cell therapies has become a major issue in cancer immunotherapy. CRS can present as a mild reaction requiring minimally invasive supportive care up to a severe systemic response resulting in patient death. Monitoring this response during these therapeutic treatments is non-trivial due to the wide range of biomarker concentrations, small sample volumes, and long assay times. CRS-associated biomarkers including CRP and ferritin vary from 10ng/mL-10mg/mL while other biomarkers (eg, IL6, IFNγ, etc.) vary from 1pg/mL-100ng/mL. At present, no analytical tool, known to us, can provide this large dynamic range simultaneously with the requisite low limit of detection in a single test.
NanoMosaic technology has the required sensitivity and dynamic range for the quantification of a large panel of CRS biomarkers in a single assay. The NanoMosaic technology is powered by silicon nanoneedle biosensors that are densely integrated on a plate and manufactured with CMOS-compatible nanofabrication processes. Each nanoneedle is a label-free biosensor, functionalized with capture antibodies, and changes its scattering spectrum when an antigen binds to its surface. Each analyte specific sensing area consists a total of ~24k nanoneedles divided into a digital region (~20k nanoneedles), an analog region (~3k nanoneedles) and a fabrication QC region (~1k nanoneedles). The colors of all nanoneedles are imaged in a single shot with a low-cost color camera. The digital nanoneedles provide the single molecule sensitivity. Therefore, at ultra-low concentration when antigens captured by the nanoneedles follow Poisson statistics, the number of antigens can be quantitated by counting the presence or absence of color changes of individual nanoneedles in a binary fashion. As the protein concentrations increase, the positive counts increase accordingly and achieve saturation when all nanoneedles capture more than one protein. Above the saturation concentration, an adjacent section of analog nanoneedles perform quantitative analysis based on the level of color change, thus providing a wider dynamic range beyond the digital counting concentration ranges. Each single analyte area, including both digital and analog sensors, is less than 500um. Therefore, high level multiplex can be achieved by parallelizing the detection in a microarray format, while maintaining the same level of sensitivity and dynamic range. We have developed various assays on the NanoMosaic platform, including cytokines such as TNF-alpha, IL6, CRP, IFNγ, as well as low-abundance proteins such as Tau proteins at 50fg/mL, in different matrices.
Prognostic monitoring of the inflammatory immune response requires simultaneous measurement of multiple cytokines at widely divergent concentrations. NanoMosaic technology provides the sensitivity, dynamic range and multiplexing capacity required to fully integrate patient immune response into therapeutic development and decision making.
Citation Format: Qimin Quan, Joshua Ritchey, Mark Clenow, Joe Wilkinson, John Geanacopoulos, John Boyce. Digital nanoneedle biosensors enable comprehensive monitoring of systemic inflammatory response to immunotherapies [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5540.