Ullah Ubaid, Saleem Seerat, Farooq Muddassar, Yameen Basit, Cheema M Imran
Department of Electrical Engineering, Lahore University of Management Sciences, Lahore, Pakistan.
Department of Chemistry and Chemical Engineering, Lahore University of Management Sciences, Lahore, Pakistan.
Biomed Opt Express. 2024 Feb 6;15(3):1428-1436. doi: 10.1364/BOE.516892. eCollection 2024 Mar 1.
Despite existing for millennia, tuberculosis (TB) remains a persistent global health challenge. A significant obstacle in controlling TB spread is the need for a rapid, portable, sensitive, and accurate diagnostic test. Currently, sputum culture stands as a benchmark test for TB diagnosis. Although highly reliable, it necessitates advanced laboratory facilities and involves considerable testing time. In this context, we present a rapid, portable, and cost-effective optical fiber sensor designed to measure lipoarabinomannan (LAM), a TB biomarker found in patients' urine samples. Our sensing approach is based on the applications of phase shift-cavity ringdown spectroscopy (PS-CRDS) to an optical fiber cavity created by two fiber Bragg gratings. A tapered fiber is spliced inside the optical cavity to serve as the sensing head. We functionalize the tapered fiber surface with anti-LAM antigen CS-35 through a unique chemistry, creating a strong affinity for LAM molecules. We measure the phase difference between the cavity transmission and the reference modulating signal at the cavity output. The measured phase is directly proportional to the injected LAM concentrations in aqueous solutions over the sensing head. Our demonstrated sensor provides a detection limit of 10 pg/mL and a sensitivity of 0.026°/pg/mL. This sensor holds promise for numerous applications in the healthcare sector, particularly in low-resource settings.
尽管结核病已存在数千年，但它仍然是全球持续面临的健康挑战。控制结核病传播的一个重大障碍是需要一种快速、便携、灵敏且准确的诊断测试。目前，痰培养是结核病诊断的基准测试。尽管它高度可靠，但需要先进的实验室设施且检测时间较长。在此背景下，我们提出了一种快速、便携且经济高效的光纤传感器，旨在测量脂阿拉伯甘露聚糖（LAM），这是一种在患者尿液样本中发现的结核病生物标志物。我们的传感方法基于将相移腔衰荡光谱（PS-CRDS）应用于由两个光纤布拉格光栅创建的光纤腔。在光腔内熔接一根锥形光纤作为传感头。我们通过独特的化学方法用抗LAM抗原CS-35对锥形光纤表面进行功能化，使其对LAM分子具有很强的亲和力。我们测量腔传输与腔输出处参考调制信号之间的相位差。所测相位与传感头处水溶液中注入的LAM浓度成正比。我们展示的传感器检测限为10 pg/mL，灵敏度为0.026°/pg/mL。该传感器在医疗保健领域，特别是在资源匮乏地区有众多应用前景。
