基于氢键诱导的纳米金比色传感器实时检测脂肪酶活性

A Real-Time Colorimetric Sensor for Determination of Lipase Activity Based on Hydrogen-Bonding RecognitionInduced Color Change of Gold Nanoparticles

以巯基乙酸甲酯（MT）修饰的纳米金（Au NPs）为探针,构建了比色生物传感器检测脂肪酶活性。在p H 6.5弱酸性条件下,脂肪酶水解MT-Au NPs上的酯键生成带负电荷的羧酸根;在p H 3.0的酸性条件下,探针间会产生强烈的氢键作用使Au NPs聚集,基于此可以检测脂肪酶活性。考察了温度、p H等因素对传感器响应信号的影响。MT-Au NPs溶液在650和520 nm处的吸光度比值A650/A520与脂肪酶活性大小在3.0×10^-4-4.5×10^-2U/m L范围内呈现良好的线性关系,检出限为2.25×10^-4U/m L（S/N=3）。测定了5种商品化脂肪酶的活性,实验结果与恒电位滴定法测定结果一致,证明本方法具有良好的实用性。

A colorimetric biosensor for detection of lipase activity was constructed by methyl thioglycolate（ MT） modified gold nanoparticles（ Au NPs）. Under slightly acidic condition（ p H = 6. 5）,lipases catalyzed the hydrolysis of the ester bond of MT on the surface of MT-Au NPs,exposing carboxyl group. When p H was adjusted to p H = 3. 0,the hydrogen-bonding among carboxyl groups induced the aggregation of Au NPs,accompanying a color change,based on which the quantitative detection of lipase activity could be achieved.Effects of reaction temperature and p H on the detection of lipase activity were investigated. The absorbance ratio（ A650/ A520） of the MT-Au NPs solution at 650 nm and 520 nm was linear with the lipase activity ranging from 3. 0 × 10^-4U / m L to 4. 5 × 10^-2U / m L and a detection limit down to 2. 25 × 10^-4U / m L（ S / N = 3） was achieved. The proposed method was applied to detect the activity of five commercial lipase samples,and the results were consistent with those obtained with a p H-stat potentiometric titration method,demonstrating the practicability of this method.