Lee Chung-Hun, Wang Shih-Chang, Yuan Chiun-Jye, Wen Meng-Fang, Chang Ku-Shang
Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, ROC.
Biosens Bioelectron. 2007 Jan 15;22(6):877-84. doi: 10.1016/j.bios.2006.03.008. Epub 2006 Apr 27.
Different strategies, including palladium electrodeposition (Pd(CV)), Pd sputtering (Pd(S)) and Nafion-solubilized carbon nanotube casting (Nafion/CNT), were used to modify screen-printed carbon electrodes (SPCEs) for the fabrication of amperometric enzyme biosensors. The electrochemical properties of the bare and modified SPCEs and the optimal conditions for surface modification were determined. The electrochemical response of the bare SPCE to H(2)O(2) under the potential of 0.3 V could be improved about 100-fold by Pd modification by electrodeposition or sputtering. By contrast, the electrochemical response of the bare SPCE was enhanced by only about 11-fold by Nafion/CNT casting. Moreover, the Pd(CV)-SPCEs exhibited better reproducibility of electrochemical response (a relative standard deviation (R.S.D.)<6.0%) than freshly prepared Pd(S)-SPCEs (R.S.D.>10%). The glucose biosensor fabricated from Pd-modified electrodes could be stored for up to 108 days without loosing significant activity. The Pd(CV)-SPCE also showed very reliable signal characteristics upon 50 consecutively repeated measurements of ascorbic acid. The electrocatalytic detection of the Pd-SPCE was combined with additional advantages of resistance to surface fouling and hence good stability. In conclusion, this study demonstrated that deposition of Pd thin film on SPCEs by electrodeposition or sputtering provided superior enhancement of electrochemical properties compared to Nafion/CNT-SPCEs. Despite their high electrochemical response, Pd(S)-SPCEs required an activation process to improve stability and Pd(CV)-SPCEs suffered from poor between electrode reproducibility.
采用不同策略，包括钯电沉积（Pd(CV)）、钯溅射（Pd(S)）和全氟磺酸溶解的碳纳米管浇铸（Nafion/CNT），对丝网印刷碳电极（SPCEs）进行修饰，以制备电流型酶生物传感器。测定了裸电极和修饰后的SPCEs的电化学性质以及表面修饰的最佳条件。通过电沉积或溅射进行钯修饰，可使裸SPCE在0.3 V电位下对H₂O₂的电化学响应提高约100倍。相比之下，通过Nafion/CNT浇铸仅使裸SPCE的电化学响应提高约11倍。此外，Pd(CV)-SPCEs的电化学响应重现性更好（相对标准偏差（R.S.D.）<6.0%），优于新制备的Pd(S)-SPCEs（R.S.D.>10%）。由钯修饰电极制备的葡萄糖生物传感器可储存长达108天而不会显著丧失活性。在对抗坏血酸进行50次连续重复测量时，Pd(CV)-SPCE也显示出非常可靠的信号特征。Pd-SPCE的电催化检测还具有抗表面污染的额外优势，因此稳定性良好。总之，本研究表明，与Nafion/CNT-SPCEs相比，通过电沉积或溅射在SPCEs上沉积钯薄膜可提供更优异的电化学性质增强效果。尽管Pd(S)-SPCEs具有高电化学响应，但需要活化过程来提高稳定性，而Pd(CV)-SPCEs存在电极间重现性差的问题。
