传感器类型
综述或非传感器论文
检测对象
S100β(S100β)、GFAP(GFAP)、NSE(NSE)、UCH-L1(UCH-L1)、MBP(MBP)、磷酸化神经丝H(pNF-H)、C-tau(c-tau)、SBDP(SBDP)、F2-异前列腺素(F2-isoprostane);样品基质:血清、血浆、脑脊液(CSF)
检测原理
以多联免疫生物传感器为代表,血清或脑脊液中的TBI标志物与固定捕获抗体结合,形成免疫复合物。标记抗体(量子点、荧光、磁珠或电化学发光标记)或酶促反应将结合事件转换为光学、电化学或磁信号。侧流/阵列中,量子点不同发射波长可区分多靶标;简化酪胺信号放大(TSA)通过HRP催化酪胺自由基沉积到邻近位点,实现约100倍信号放大;多酶级联利用LOx、HRP、GDH将去甲肾上腺素、乳酸、葡萄糖等代谢物转化为NADH或醌类输出,经光学或电化学读出。信号强度随标志物浓度增加而增加,可定量或半定量评估TBI严重程度。
检测灵敏度
LOD/蛋白检测限(表3): 0.001–1.0 ng ml−1(Arrayed imaging reflectometry bioassay system);<1 ng ml−1(Advanced Liquid Logic、MagnaBio Sciences、MSA、MSD、QTL、RAPTOR);1–100 ng ml−1(mBio MQ)
效应效果
综述指出,基于症状和神经认知测试的现场评估在战斗或运动环境中可产生25%–34%假阳性,且受疲劳、压力和药物影响。侧流多联试纸条在20例严重TBI患者伤后10 h检测到GFAP、S100β、NSE升高,随后140 h下降,但均值变异系数较大,且未报告敏感性和精密度。NRL多联阵列采用简化酪胺信号放大(TSA)可获得约100倍信号改善,但增加操作步骤。表3商业传感器蛋白检测限包括0.001–1.0、<1、1–100 ng ml−1,检测时间2–30 min,支持多联检测。作者认为多标志物面板结合现场生物传感器可改善TBI分诊,但需验证特异性、抗干扰和临床一致性。
传感器的构成
- 基底/换能器:侧流层析试纸条(lateral flow test strip),承载样品流动与免疫反应
- 识别元件:针对GFAP、S100β、NSE、UCH-L1等的抗体(antibodies),特异性捕获TBI标志物
- 信号标记物:量子点标记抗体(QD-labeled antibodies),以不同荧光发射区分多联靶标
- 信号放大层:简化酪胺信号放大(TSA),通过酪胺沉积提高信号约100倍
- 酶促信号层:乳酸氧化酶(LOx)、辣根过氧化物酶(HRP)、葡萄糖脱氢酶(GDH),组成多酶级联
- 读出模块:电池供电读取器(battery-powered reader)及光学/电化学检测器,读取荧光或电化学信号
中文摘要
创伤性脑损伤(TBI)由外力导致脑组织快速加速、减速或颅骨穿透引起。目前临床主要依据意识丧失、行为改变、格拉斯哥昏迷量表(GCS)及神经认知测试进行初步评估,但这些方法易受压力、疲劳、药物和微损伤影响,存在假阳性和假阴性。脑损伤后神经元损伤及生理反应相关生化标志物正在被识别,可在血液或脑脊液中检测。能够在循环液中快速测量这些标志物的生物传感器可为现场分诊提供解决方案,但需满足三项条件:识别试剂具有足够敏感性和特异性;传感器能快速同时定量多种标志物;传感器与试剂适合实验室外使用。本文综述TBI病理生理、候选标志物、验证挑战及可用于现场分诊的生物传感器技术。
英文摘要
Traumatic brain injury (TBI) results from an event that causes rapid acceleration and deceleration of the brain or penetration of the skull with an object. Responses to stimuli and questions, loss of consciousness, and altered behavior are symptoms currently used to justify brain imaging for diagnosis and therapeutic guidance. Tests based on such symptoms are susceptible to false-positive and false-negative results due to stress, fatigue, and medications. Biochemical markers of neuronal damage and the physiological response to that damage are being identified. Biosensors capable of rapid measurement of such markers in the circulation offer a solution for on-site triage, as long as three criteria are met: (a) Recognition reagents can be identified that are sufficiently sensitive and specific, (b) the biosensor can provide quantitative assessment of multiple markers rapidly and simultaneously, and (c) both the sensor and reagents are designed for use outside the laboratory.