[
    {
        "id": "authors:cvqpm-g7q63",
        "collection": "authors",
        "collection_id": "cvqpm-g7q63",
        "cite_using_url": "https://authors.library.caltech.edu/records/cvqpm-g7q63",
        "type": "article",
        "title": "Hydrogel Encapsulation of a Designed Fluorescent Protein Biosensor for Continuous Measurements of Sub-100 nM Nicotine",
        "author": [
            {
                "family_name": "Nichols",
                "given_name": "Aaron L.",
                "orcid": "0000-0001-9341-0049",
                "clpid": "Nichols-Aaron-L"
            },
            {
                "family_name": "Marotta",
                "given_name": "Christopher B.",
                "orcid": "0000-0002-3110-0819",
                "clpid": "Marotta-Christopher-Bruno"
            },
            {
                "family_name": "Friesenhahn",
                "given_name": "Nicholas J.",
                "orcid": "0000-0002-8129-0171",
                "clpid": "Friesenhahn-Nicholas-J"
            },
            {
                "family_name": "Dalfonzo",
                "given_name": "Sophia R.",
                "clpid": "Dalfonzo-Sophia-R"
            },
            {
                "family_name": "Muthusamy",
                "given_name": "Anand",
                "clpid": "Muthusamy-Anand"
            },
            {
                "family_name": "Wagenaar",
                "given_name": "Daniel A.",
                "orcid": "0000-0002-6222-761X",
                "clpid": "Wagenaar-D-A"
            },
            {
                "family_name": "Mayo",
                "given_name": "Stephen L.",
                "orcid": "0000-0002-9785-5018",
                "clpid": "Mayo-S-L"
            },
            {
                "family_name": "Dougherty",
                "given_name": "Dennis A.",
                "orcid": "0000-0003-1464-2461",
                "clpid": "Dougherty-D-A"
            },
            {
                "family_name": "Lester",
                "given_name": "Henry A.",
                "orcid": "0000-0002-5470-5255",
                "clpid": "Lester-H-A"
            }
        ],
        "abstract": "<div class=\"article_abstract-content hlFld-Abstract\">\n<div class=\"article_abstract-content hlFld-Abstract\">\n<p class=\"articleBody_abstractText\">The reinforcing, addictive, and therapeutic properties of nicotine depend strongly on the concentration and time dependence of nicotine in human biofluids. This pattern, termed&nbsp;<em>[nicotine]</em><sub><em>t</em></sub>, varies markedly among methods of nicotine consumption and, for a given method, among individual users. Measuring&nbsp;<em>[nicotine]</em><sub><em>t</em></sub> presents challenges: current approaches are expensive, invasive, tedious, and discontinuous. We report the entrapment of a purified, previously developed fluorescent biosensor protein, iNicSnFR12, in hydrogels. We optimized poly(ethylene glycol) diacrylate hydrogels for optical clarity and straightforward slicing. With fluorescence photometry of the hydrogels in a microscope or an integrated miniscope, [nicotine] is detected within a few min at the smoking- and vaping-relevant level of 10&ndash;100 nM (1.62&ndash;16.2 ng/mL), in a 250 &mu;m thick hydrogel at the end of a 400 &mu;m diameter multimode fiber optic. Concentration&ndash;response relationships are consistent with previous measurements of isolated iNicSnFR12. Leaching of iNicSnFR12 from the hydrogel and inactivation of iNicSnFR12 are minimal for several days, and reversible nicotine-induced fluorescence occurs at least 10 months after casting. This work provides the molecular, photophysical, and mechanical bases for minimally invasive, personal, wearable, continuous [nicotine] monitoring with straightforward extensions to existing, homologous &ldquo;iDrugSnFR&rdquo; proteins for other abused and prescribed drugs.</p>\n</div>\n</div>",
        "doi": "10.1021/acsabm.5c01418",
        "issn": "2576-6422",
        "publisher": "American Chemical Society",
        "publication": "ACS Applied Bio Materials",
        "publication_date": "2026-01-19",
        "series_number": "2",
        "volume": "9",
        "issue": "2",
        "pages": "765-774"
    }
]