Vaddiraju Santhisagar, Legassey Allen, Qiang Liangliang, Wang Yan, Burgess Diane J, Papadimitrakopoulos Fotios
Biorasis Inc. Technology Incubation Program, University of Connecticut, Storrs, CT 06269, USA.
J Diabetes Sci Technol. 2013 Mar 1;7(2):441-51. doi: 10.1177/193229681300700221.
Needle-implantable sensors have shown to provide reliable continuous glucose monitoring for diabetes management. In order to reduce tissue injury during sensor implantation, there is a constant need for device size reduction, which imposes challenges in terms of sensitivity and reliability, as part of decreasing signal-to-noise and increasing layer complexity. Herein, we report sensitivity enhancement via electrochemical surface rebuilding of the working electrode (WE), which creates a three-dimensional nanoporous configuration with increased surface area.
The gold WE was electrochemically rebuilt to render its surface nanoporous followed by decoration with platinum nanoparticles. The efficacy of such process was studied using sensor sensitivity against hydrogen peroxide (H2O2). For glucose detection, the WE was further coated with five layers, namely, (1) polyphenol, (2) glucose oxidase, (3) polyurethane, (4) catalase, and (5) dexamethasone-releasing poly(vinyl alcohol)/poly(lactic-co-glycolic acid) composite. The amperometric response of the glucose sensor was noted in vitro and in vivo.
Scanning electron microscopy revealed that electrochemical rebuilding of the WE produced a nanoporous morphology that resulted in a 20-fold enhancement in H2O2 sensitivity, while retaining >98% selectivity. This afforded a 4-5-fold increase in overall glucose response of the glucose sensor when compared with a control sensor with no surface rebuilding and fittable only within an 18 G needle. The sensor was able to reproducibly track in vivo glycemic events, despite the large background currents typically encountered during animal testing.
Enhanced sensor performance in terms of sensitivity and large signal-to-noise ratio has been attained via electrochemical rebuilding of the WE. This approach also bypasses the need for conventional and nanostructured mediators currently employed to enhance sensor performance.
可植入针式传感器已被证明可为糖尿病管理提供可靠的连续血糖监测。为了减少传感器植入过程中的组织损伤，一直需要减小设备尺寸，这在灵敏度和可靠性方面带来了挑战，因为这会降低信噪比并增加层的复杂性。在此，我们报告了通过工作电极（WE）的电化学表面重建来提高灵敏度，该重建创建了具有增加表面积的三维纳米多孔结构。
对金工作电极进行电化学重建，使其表面形成纳米多孔结构，然后用铂纳米颗粒进行修饰。使用传感器对过氧化氢（H2O2）的灵敏度研究了该过程的效果。对于葡萄糖检测，工作电极进一步涂覆五层，即（1）多酚、（2）葡萄糖氧化酶、（3）聚氨酯、（4）过氧化氢酶和（5）释放地塞米松的聚乙烯醇/聚乳酸-乙醇酸共聚物复合材料。记录了葡萄糖传感器在体外和体内的安培响应。
扫描电子显微镜显示，工作电极的电化学重建产生了纳米多孔形态，使H2O2灵敏度提高了20倍，同时保留了>98%的选择性。与未进行表面重建且只能适配18G针的对照传感器相比，这使得葡萄糖传感器的整体葡萄糖响应提高了4-5倍。尽管在动物测试中通常会遇到较大的背景电流，但该传感器仍能够可重复地跟踪体内血糖事件。
通过工作电极的电化学重建，在灵敏度和大信噪比方面实现了传感器性能的增强。这种方法还避免了目前用于提高传感器性能的传统和纳米结构介质的需求。
