Haun, JeredDevaraj, NealMarinelli, BrettLee, HakhoWeissleder, Ralph2019-09-212011Haun, Jered B., Neal K. Devaraj, Brett S. Marinelli, Hakho Lee, and Ralph Weissleder. 2011. “Probing Intracellular Biomarkers and Mediators of Cell Activation Using Nanosensors and Bioorthogonal Chemistry.” ACS Nano 5 (4): 3204–13. https://doi.org/10.1021/nn200333m.1936-08511936-086Xhttp://nrs.harvard.edu/urn-3:HUL.InstRepos:41384365Nanomaterials offer unique physical properties that make them ideal biosensors for scant cell populations. However, specific targeting of nanoparticles to intracellular proteins has been challenging. Here, we describe a technique to improve intracellular biomarker sensing using nanoparticles that is based on bioorthogonal chemistry. Using trans-cyclooctene-modified affinity ligands that are administered to semipermeabilized cells and revealed by cycloaddition reaction with tetrazine-conjugated nanoparticles, we demonstrate site-specific amplification of nanomaterial binding. We also show that this technique Is capable of sensing protein biomarkers and phosho-protein signal mediators, both within the cytosol and nucleus, via magnetic or fluorescent modalities. We expect the described method will have broad applications in nanomaterial-based diagnostics and therapeutics.en-USJournal Article2019-09-2110.1021/nn200333m