Delivered by Ingenta to: York University Libraries IP: 178.57.68.89 On: Sat, 08 Apr 2017 07:55:26 Copyright: American Scientific Publishers RESEARCH ARTICLE Copyright © 2016 American Scientific Publishers All rights reserved Printed in the United States of America Journal of Bionanoscience Vol. 10, 377–380, 2016 Naked Eye Detection of Hydrogen Peroxide by Laser Ablated Silver Nanoparticle Coated Flexible Paper Obey Koshy 1 ∗ , A. Thankappan 1 , Bini Vibin 2 , S. Thomas 1 , and A. Mujeeb 3 1 International and Inter University Centre for Nanoscience and Nanotechnology, Mahatma Gandhi University, P.D. Hills, Kottayam 686560, Kerala, India 2 International School of Photonics (ISP), CUSAT, Cochin 682022, Kerala, India 3 LBS Centre for Science and Technology, Thiruvananthapuram 695001, Kerala, India A simple enzyme free detection of hydrogen peroxide is demonstrated based on its reduction with unfunctionalized silver nanoparticles. Silver nanoparticle was synthesized by laser ablation. Nanoparticle of size about 7 nm is observed from HRTEM images. Silver nanoparticle exhibited a fading of their characteristics yellow colour with increasing concentration of hydrogen peroxide. Photoshop software was used to detect the blue colour variation of the RGB component of the sam- ples and found that the blue color varied upto 1 M. A simple colorimetric procedure thus proposed by impregnating silver nanoparticle on paper for ultrasensitive detection of H 2 O 2 without adding any chromogenic agent. The color change can be detected with naked eye from 0.01 mM to 1 M. The current method provides two advantage namely functionalization of silver nanoparticles on cellulose matrices preventing from agglomeration and simple colorimetric technique for H 2 O 2 detection. Keywords: Flexible Sensor, Silver Nanoparticle, Cellulose, Naked Eye Detection. 1. INTRODUCTION H 2 O 2 is an important mediator in the fields of biochemi- cal and environmental protection. 1 It is also the by-product of cholesterol oxidase, lactate oxidase, glucose oxidase, and so on. Therefore, the reliable, simple, sensitive, rapid, and low-cost determination of H 2 O 2 has initiated tremen- dous efforts and many kinds of H 2 O 2 sensors with high performances have been explored using surface plasma resonance, 2 fluorescence, 3 colorimetry, 4 electrochemical signals. 1 However, depending on its advantages, such as low cost, simplicity, high sensitivity, and fast response, col- orimetric technique is an optimal technique as the concen- tration range can be analysed very fast directly by naked eye without any additional instruments or procedure. The measurement of glucose in the blood can be determined quantitatively by digital electronic equipments. However the cost of this method is high and it is not con- venient to carry this equipment with patients. Moreover, these equipments suffer from wear and tear and battery worn out etc. In this regard, colorimetric sensors fabri- cated on papers were user friendly, low cost and provide an alternative to conventional systems. 5 H 2 O 2 can be deter- mined analytically by using metal, metal oxides namely Ag 1 2 Au, 4 CeO 2  5 Among them, Ag have high extinction ∗ Author to whom correspondence should be addressed. coefficient compared to Au of same size. 6 The stabiliza- tion of Ag nanoparticles is a challenge as it is easy to get oxidized due to its large exposed surface. Different methods have been explored to stabilize Ag nanoparti- cles through surface functionalization. 7 Among them the incorporation of nanoparticles on to paper/cellulose matri- ces is quite interesting due to the fact that it can be used to stabilize the nanoparticle from aggregation due to the availability of abundance of hydroxyl and carboxyl groups. Nitinaivinji et al., used red chromaticity analysis of hydro- gen peroxide by morphological decomposition of silver nanoprisms. 8 Wang et al., reported the colorimetric hydro- gen peroxide detection by silver nanoparticles in the pres- ence of mercury ions from 1–500 M. 9 Though there are several reports on the colorometric detection of hydro- gen peroxide, the use of printed silver nanoparticle on paper substrates for hydrogen peroxide sensing is lacking in literature. Paper substrates are light weight, flexible and cheap compared to other substrates. They can be used as indicator or test paper. Ornatska et al., have developed a hydrogen peroxide sensor based on ceria oxide nanoparti- cle printed on paper for colorometric probe. Though there are a few reports of silver nanoparticle printed on paper, the application of unfunctionalized silver printed on paper as a test indicator for hydrogen peroxide is lacking in the literature by laser ablation of silver disk. In addition the J. Bionanosci. 2016, Vol. 10, No. 5 1557-7910/2016/10/377/004 doi:10.1166/jbns.2016.1395 377