基于比色型适配体传感器高灵敏快速检测磷脂酰丝氨酸

目的]生物加工制备海洋活性物质是近年来的研究热点，对加工过程中目标产物的检测定量十分重要，而传统的检测方法面临很多限制，迫切需要新型简便的分析方法。本研究以磷脂酰丝氨酸（phosphatidylserine，PS）为待检物代表，构建了一种比色型适配体传感器，用于快速检测生物加工体系中的PS。方法] 带正电的壳寡糖与带负电的适配体先经静电吸附结合，PS存在条件下，适配体特异性地与PS结合导致壳寡糖释放，后者进而与带负电的纳米金结合形成具有高催化活性的过氧化物纳米酶，催化3,3’,5,5’-四甲基联苯胺（TMB）产生与PS浓度成正相关的颜色信号，测定各样品的光吸收值，并与无PS的阴性样品相比计算光吸收变化率，从而实现快速定量。并对适配体浓度、壳寡糖浓度、纳米酶催化参数进行了详细优化。结果]在最优条件下，传感器具有良好的线性检测范围（0.~-50 nmol/L）和较高的灵敏度，检测限（LOD）低至93.84 pmol/L，且具有较好的选择性、准确性和重复性，用于分析实际生物加工样品中的PS时，回收率为95.63%~110.8%，RSD均小于9%，整个分析过程仅需40 min。 结论] 本论文成功构建了一种能高灵敏快速检测PS的比色型适配体传感器。意义] 本论文为PS以及其他生物加工产物的快速检测提供新思路和研究基础。

Highly sensitive and rapid detection of phosphatidylserine based on a colorimetric aptasensor

Research background]Preparation of marine active substances by bioprocessing becomes a hot research topic in recent years. During the bioprocessing, it is very important to achieve detection of the target products, while the traditional detection methods are faced with many limitations. There is an urgent need for novel and simple analytical methods. Aim] In this study, phosphatidylserine (PS) was chosen as the model target, a colorimetric aptamer-based biosensor (aptasensor) was developed for the rapid detection of PS in bioprocessing system. Method] The positively-charged chitosan oligosaccharides and negatively-charged aptamers firstly bound through electrostatic adsorption. In the presence of PS, the aptamers specifically bound with the PS, causing the release of chitosan oligosaccharides, which in turn absorbed onto the negatively-charged gold nanoparticles to form nanozymes with high peroxide catalytic activity towards 3,3'',5,5''-tetramethyl benzidine (TMB), producing colorimetric signals which were positively correlated with the concentration of PS. The absorbance values were collected and processed into rate of change with comparison to negative samples without PS so as to achieve the rapid quantification. The key parameters, including the concentration of aptamers, concentration of chitosan oligosaccharides, and the conditions of nanozyme catalysis reaction, were optimized in details. Results] Under optimal conditions, the developed aptasensor provided a good linear detection range (0.5~50 nmol/L) and high sensitivity, with a limit of detection (LOD) as low as 93.84 pmol/L. Moreover, the aptasensor showed high selectivity, accuracy, and repeatability. Recovery rates of 95.63%~110.8% and RSD less than 9% were obtained, when analyzing the PS in the actual bioprocessing samples. Only 40 min was needed for the entire analysis process. Conclusion] An aptasensor was successfully developed for highly sensitive and rapid detection of PS. Significance] The study can provide new ideas and research basis for the rapid detection method of not only the PS but also other biological processing products.