组成图示
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传感器类型
电化学生物传感器
检测对象
依非韦伦（Efavirenz, EFV）；样品基质：醋酸缓冲液、片剂制剂甲醇稀释液
检测原理
dsDNA通过电沉积固定于PGE表面，形成识别层。EFV与dsDNA结合后，屏蔽或损伤可氧化的鸟嘌呤位点，使鸟嘌呤氧化峰电流随EFV浓度增加而线性下降，从而以峰电流变化反映药物–DNA相互作用。该过程无需外加标记物，依靠DNA内源氧化信号实现换能。另一方面，在裸PGE上，EFV在pH 3.0 Britton–Robinson缓冲液（含20%甲醇）中发生不可逆氧化，且峰电流与扫描速率线性相关，表明为吸附控制过程；通过700 mV、300 s预富集后阳极剥离，EFV氧化峰电流与浓度在0.018–2.56 ppm内线性，实现痕量测定。
检测灵敏度
dsDNA修饰PGE: LOD: 0.599 ppm；LOQ: 1.995 ppm；线性范围: 2–24 ppm；斜率: -0.0138 µA ppm−1；相关系数: -0.999。裸PGE AdsDPV: LOD: 0.0042 ppm；LOQ: 0.0138 ppm；线性范围: 0.018–2.56 ppm；斜率: 2.89 µA ppm−1；相关系数: 0.999。
效应效果
方法精密度良好：dsDNA修饰PGE日内峰电位/电流RSD为0.29%/0.96%，日间0.46%/2.22%；裸PGE日内0.35%/1.32%，日间0.60%/1.58%。EFV工作溶液4 ℃避光稳定一周。片剂测定中，标示量600 mg，dsDNA修饰PGE测得596.02 mg（RSD 1.41%，偏差0.66%），裸PGE测得600.82 mg（RSD 1.68%，偏差-0.14%）；加标偏差分别为-1.67%和2.92%。与分光光度法比较，t和F检验无显著差异，辅料无干扰。作者认为该方法快速、低成本、适合药物制剂质控和抗HIV药物筛选。
传感器的构成
- 工作电极/基底：一次性铅笔石墨电极（PGE），作为导电基底和电化学换能器，提供电子转移界面。
- 电极预处理：在0.5 M醋酸缓冲液（pH 4.80，含0.02 M NaCl）中施加+1.4 V 60 s，清洁/活化PGE表面。
- 识别元件层：鱼精双链DNA（dsDNA），在2 ppm dsDNA溶液中施加+0.5 V 240 s固定于PGE，作为药物识别层。
- 内源信号基团：dsDNA中的鸟嘌呤（G）氧化位点，提供可监测氧化峰，随EFV结合而降低。
- 检测读出：差分脉冲伏安（DPV）/吸附剥离差分脉冲伏安（AdsDPV），监测鸟嘌呤氧化峰电流或EFV氧化峰电流。
中文摘要
本文报道了一种基于一次性铅笔石墨电极（PGE）的电化学DNA生物传感器，用于研究抗HIV-1药物依非韦伦（Efavirenz, EFV）与固定在电极表面的鱼精双链DNA（dsDNA）之间的相互作用。采用差分脉冲伏安法（DPV）监测dsDNA中鸟嘌呤氧化信号的变化：EFV与dsDNA作用后，dsDNA修饰PGE的鸟嘌呤信号低于未作用电极，且随EFV浓度增加呈线性下降，线性范围为2–24 ppm。同时优化了dsDNA固定条件、EFV作用时间和浓度等参数，并计算了灵敏度、选择性、准确度、精密度、检测限、定量限和重现性。此外，EFV在PGE上表现为不可逆氧化且受吸附控制，因此建立了差分脉冲吸附剥离伏安法（AdsDPV）直接测定EFV，在0.018–2.56 ppm范围内线性。两种方法均经方法学验证并应用于EFV药物制剂分析，表明该传感器可用于快速、简单、低成本地检测EFV–dsDNA相互作用和药物含量。
英文摘要
The interaction of Efavirenz (EFV) with fish sperm dsDNA immobilized onto pencil graphite electrode (PGE) has been studied by using differential pulse voltammetric technique using an electrochemical DNA biosensor. The guanine signal was lower with (double stranded-DNA) dsDNA-treated PGE than the untreated electrode after the interaction with EFV occurred. The changes in the experimental parameters such as the accumulation time and the concentration of EFV were also studied. All necessary parameters such as sensitivity, selectivity, accuracy and precision were calculated. In addition, the detection and determination limits, reproducibility and applicability of the analysis to pharmaceutical dosage forms were also investigated. These results showed that this DNA biosensor could be used for the sensitive, rapid simple and cost effective detection and determination of EFV-dsDNA interaction. The linearity was between 2 and 24 ppm of EFV concentration on guanine signal decreasing curve. EFV showed an irreversible oxidation behavior at all investigated pH values. This oxidation step was adsorption controlled on PGE. Hence, differential pulse adsorptive stripping (AdsDPV) voltammetric method was developed for the determination of EFV. Accumulation time and potential were optimized. Under these conditions, the current showed a linear dependence with concentration in the range between 0.018 and 2.56 ppm. Both determination methods were fully validated and applied for the analysis of EFV pharmaceutical dosage form.