Real Time Monitoring of Layer-by-Layer Polyelectrolyte Deposition and Bacterial Enzyme Detection in Nanoporous Anodized Aluminum Oxide
Real Time Monitoring of Layer-by-Layer Polyelectrolyte Deposition and Bacterial Enzyme Detection in Nanoporous Anodized Aluminum Oxide
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DOI：
10.1021/ac504626m
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发表时间：
2015-04-07
影响因子：
7.4
通讯作者：
Schoenherr, Holger
中科院分区：
文献类型：
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作者：
Krismastuti, Fransiska Sri Herwahyu;Bayat, Haider;Schoenherr, Holger
多孔阳极氧化铝 (pAAO) 是一种纳米结构材料，由于其光学特性，适合光学生物传感器的设计，其中该材料孔中的相互作用被转换为干涉反射率位移。在这项研究中，开发了一种基于 pAAO 的生物传感器作为检测蛋白酶 K 的生物传感平台，蛋白酶 K 是一种易于使用的铜绿假单胞菌产生的蛋白酶模型系统。 pAAO 孔壁通过逐层 (LbL) 沉积技术进行装饰，分别使用聚（4-苯乙烯磺酸钠）和聚 L-赖氨酸作为带负电和带正电的聚电解质。用于观察 LbL 沉积过程中 pAAO 光学性质的干涉反射光谱表明，聚电解质沉积到孔壁上会增加净折射率，从而使有效光学厚度 (BOT) 发生红移。与蛋白酶 K 一起孵育后，观察到 EOT 发生明显的蓝移，这是由于多聚 L-赖氨酸成分的酶降解导致 LbL 膜不稳定。该结果通过扫描电子显微镜结果得到证实。最后，作为原理验证，我们展示了基于 pAAO 的无标记生物传感平台检测人体伤口液中蛋白酶 K 存在的能力，突出了检测慢性伤口细菌感染的潜力。
Porous anodized aluminum oxide (pAAO),is a nano-structured material, which due to its optical properties lends itself to the design of optical biosensors where interactions in the pores of this material are transduced into interferometric reflectance shifts. In this study, a pAAO-based biosensor was developed as a biosensing platform to detect proteinase K, an enzyme which, is a readily available model system for the proteinase produced by Pseudomonas aeruginosa. The pAAO pore walls are decorated by means of the layer-by-layer (LbL) deposition technique using poly(sodium-4-styrenesulfonate) and poly-L-lysine as negatively and positively charged polyelectrolytes, respectively. Interferometric reflectance spectroscopy utilized to observe the optical properties of pAAO during LbL deposition shows that the deposition of the polyelectrolyte onto the pore walls increase the net refractive index, thus red-shifting the effective optical thickness (BOT). Upon incubation with proteinase K, a conspicuous blue shift of the EOT observed, which is attributed to the destabilization of the LbL film upon enzymatic degradation of the poly-L-lysine components. This result is confirmed by scanning electron microscopy results. Finally, as a proof-Of-principle, we demonstrate the ability of the label-free pAAO-based biosensing platform to detect the presence of the proteinase K in human Wound fluid, highlighting the potential for detection of bacterial infections in chronic wounds.