School of Chemistry , University of Birmingham , Birmingham B15 2TT , U.K.
Department of Chemistry and Biochemistry , University of Hull , Hull HU6 7RX , U.K.
Anal Chem. 2019 Jun 4;91(11):7366-7372. doi: 10.1021/acs.analchem.9b01231. Epub 2019 May 14.
We report a method where the refractive index increments of an iron storage protein, ferritin, and apoferritin (ferritin minus iron) were measured over the wavelength range of 450-678 nm to determine the average iron content of the protein. The protein used in this study had ∼3375 iron atoms per molecule. The measurement of optical dispersion over the broad wavelength range was enabled by the use of mesoporous leaky waveguides (LWs) made of chitosan. We present a facile approach for fabricating mesoporous chitosan waveguides for improving the measurement sensitivity of macromolecules such as ferritin. Mesoporous materials allow macromolecules to diffuse into the waveguide, maximizing their interaction with the optical mode and thus increasing sensitivity by a factor of ∼9 in comparison to nonporous waveguides. The sensitivity was further improved and selectivity toward ferritin was achieved by the incorporation of antibodies in the waveguide. The method presented in this work is a significant advance over the state of the art method, the enzyme linked immunosorbent assay (ELISA) used in clinics, because it allows determining the average content of ferritin in a single step. The average iron content of ferritin is an important marker for conditions such as injury, inflammation, and infection. Thus, the approach presented here of measuring optical dispersion to determine the average iron content of ferritin has a significant potential to improve the point of care analysis of the protein for disease diagnosis and screening.
我们报告了一种方法，该方法可以在 450-678nm 的波长范围内测量铁储存蛋白铁蛋白和脱铁铁蛋白（铁蛋白减去铁）的折射率增量，以确定蛋白质的平均铁含量。本研究中使用的蛋白质每个分子约有 3375 个铁原子。通过使用壳聚糖制成的中孔漏波导（LW），可以在宽波长范围内测量光的色散。我们提出了一种简便的方法来制造中孔壳聚糖波导，以提高铁蛋白等大分子的测量灵敏度。介孔材料允许大分子扩散到波导中，使它们与光学模式的相互作用最大化，从而将灵敏度提高约 9 倍，与非多孔波导相比。通过在波导中加入抗体，进一步提高了灵敏度并实现了对铁蛋白的选择性。与临床上使用的酶联免疫吸附测定（ELISA）等现有技术方法相比，本工作中提出的方法是一个重大进展，因为它可以一步确定铁蛋白的平均含量。铁蛋白的平均铁含量是损伤、炎症和感染等情况的重要标志物。因此，这里提出的通过测量光的色散来确定铁蛋白的平均铁含量的方法，在改善该蛋白用于疾病诊断和筛查的即时检测分析方面具有重要的潜力。
