Paper-Based Sensor for Electrochemical Detection of Silver Nanoparticle Labels by Galvanic Exchange
Paper-Based Sensor for Electrochemical Detection of Silver Nanoparticle Labels by Galvanic Exchange
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DOI：
10.1021/acssensors.5b00051
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发表时间：
2016-01-01
期刊：
影响因子：
8.9
通讯作者：
Crooks, Richard M.
中科院分区：
文献类型：
--
作者：
Cunningham, Josephine C.;Kogan, Molly R.;Crooks, Richard M.
在这里，我们报道了一种三维纸流控装置，用于电化学检测银纳米颗粒(AgNPs)标记的生物分子。这种新的传感器，我们称之为NoSlip，代表了我们之前报道的oSlip系统的重大改进。具体地说，NoSlip中AgNPs的检测是基于原电池交换而不是化学氧化剂(OSlip中的漂白剂或MnO4-)。电交换是通过在工作电极上沉积非常少量的金来实现的。一旦利用磁力将AgNP标记带到电极附近，一小部分Au-0被电化学氧化为Au3+。Au3+与AgNPs反应生成Ag+和Au-0。然后用阳极溶出伏安法检测Ag+。这种新的方法解决了oSlip的三个缺点，同时简化了基本的传感器外形。首先，NoSlip解决了氧化剂不稳定的问题，因为用于电产生氧化剂(Au3+)的电极上的Au0涂层具有固有的稳定性。此外，AU3+是一种比漂白剂或MnO4-更温和的氧化剂，因此它不会攻击NoSlip的主要成分。最后，NoSlip消除了滑移层的需要，因为氧化剂(Au3+)是按需产生的。NoSlip能够检测浓度低至2.1 pm的AgNP标记，结果的时间类似于7分钟，实验室规模的成本(不包括特定用途的试剂)为0.30美元。
Here we report a three-dimensional paper fluidic device configured for electrochemical detection of biomolecules labeled with silver nanoparticles (AgNPs). This new sensor, which we call a NoSlip, represents a major improvement of our previously reported oSlip system. Specifically, detection of AgNPs in the NoSlip is based on galvanic exchange rather than a chemical oxidant (bleach or MnO4- in the oSlip). Galvanic exchange is implemented by depositing a very small amount of gold onto the working electrode. Once the AgNP labels are brought into the proximity of the electrode through the use of magnetic force, a fraction of the Au-0 is electrochemically oxidized to Au3+. The Au3+ reacts with the AgNPs to form Ag+ and Au-0. The Ag+ is then detected by anodic stripping voltammetry. This new methodology resolves three shortcomings of the oSlip while simultaneously simplifying the basic sensor form factor. First, the NoSlip resolves an oxidant instability issue because of the inherent stability of the Au0 coating on the electrode that is used to electrogenerate the oxidant (Au3+). Additionally, Au3+ is a milder oxidizing agent than bleach or MnO4-, so it does not attack the major components of the NoSlip. Finally, the NoSlip eliminates the need for a slip layer because the oxidant (Au3+) is electrogenerated on demand. The NoSlip is able to detect AgNP labels down to concentrations as low as 2.1 pM, the time to result is similar to 7 min, and the cost at the laboratory scale, not including application-specific reagents, is $0.30.