Department of Chemistry, Alfaisal University, Al Zahrawi Street, Al Maather, Al Takhassusi Road, Riyadh 11533, Saudi Arabia.
Department of Chemistry, Alfaisal University, Al Zahrawi Street, Al Maather, Al Takhassusi Road, Riyadh 11533, Saudi Arabia; Department of Genetics, King Faisal Specialist Hospital and Research Center, Zahrawi Street, Al Maather, Riyadh 11211, Saudi Arabia.
Biosens Bioelectron. 2018 Mar 15;101:282-289. doi: 10.1016/j.bios.2017.10.015. Epub 2017 Oct 10.
Spinal muscular atrophy is an untreatable potentially fatal hereditary disorder caused by loss-of-function mutations in the survival motor neuron (SMN) 1 gene which encodes the SMN protein. Currently, definitive diagnosis relies on the demonstration of biallelic pathogenic variants in SMN1 gene. Therefore, there is an urgent unmet need to accurately quantify SMN protein levels for screening and therapeutic monitoring of symptomatic newborn and SMA patients, respectively. Here, we developed a voltammetric immunosensor for the sensitive detection of SMN protein based on covalently functionalized carbon nanofiber-modified screen printed electrodes. A comparative study of six different carbon nanomaterial-modified electrodes (carbon, graphene (G), graphene oxide (GO), single wall carbon nanotube (SWCNT), multi-wall carbon nanotube (MWCNT), and carbon nanofiber (CNF)) was performed. 4-carboxyphenyl layers were covalently grafted on the six electrodes by electroreduction of diazonium salt. Then, the terminal carboxylic moieties on the electrodes surfaces were utilized to immobilize the SMN antibody via EDC/NHS chemistry and to fabricate the immunosensors. The electrochemical characterization and analytical performance of the six immunosensors suggest that carbon nanofiber is a better electrode material for the SMN immunosensor. The voltammetric SMN carbon nanofiber-based immunosensor showed high sensitivity (detection limit of 0.75pg/ml) and selectivity against other proteins such as cystic fibrosis transmembrane conductance regulator (CFTR) and dystrophin (DMD). We suggest that this novel biosensor is superior to other developed assays for SMN detection in terms of lower cost, higher sensitivity, simplicity and capability of high throughput screening.
脊髓性肌萎缩症是一种无法治疗的潜在致命遗传性疾病，由生存运动神经元 (SMN) 1 基因的功能丧失突变引起，该基因编码 SMN 蛋白。目前，明确诊断依赖于 SMN1 基因中双等位致病性变异的证明。因此，迫切需要准确地定量 SMN 蛋白水平，分别用于症状性新生儿和 SMA 患者的筛查和治疗监测。在这里，我们开发了一种基于共价功能化碳纳米纤维修饰丝网印刷电极的伏安免疫传感器，用于敏感检测 SMN 蛋白。对六种不同的碳纳米材料修饰电极（碳、石墨烯 (G)、氧化石墨烯 (GO)、单壁碳纳米管 (SWCNT)、多壁碳纳米管 (MWCNT) 和碳纳米纤维 (CNF)）进行了比较研究。通过电化学还原重氮盐将 4-羧基苯层共价接枝到六个电极上。然后，通过 EDC/NHS 化学将电极表面的末端羧酸基团用于固定 SMN 抗体，并制备免疫传感器。六种免疫传感器的电化学表征和分析性能表明，碳纳米纤维是用于 SMN 免疫传感器的更好的电极材料。基于碳纳米纤维的伏安 SMN 免疫传感器对其他蛋白质（如囊性纤维化跨膜电导调节剂 (CFTR) 和肌营养不良蛋白 (DMD)）表现出高灵敏度（检测限为 0.75pg/ml）和选择性。我们认为，与其他开发的 SMN 检测方法相比，这种新型生物传感器在成本、灵敏度、简单性和高通量筛选能力方面具有优势。
