**Meet the editor**

Wen Wang is a Professor at the Institute of Acoustics, Chinese Academy of Sciences (IOA-CAS), who received his MS degree from the Central South University of China in 2002, and his PhD degree from IOA-CAS in 2005. From 2005 to 2009, he worked as a postdoctoral researcher and research professor at the microsystem laboratory of the Ajou University in Korea. Prof. Wang

worked at the Freiburg University supported by the Humboldt Foundation as a guest professor in 2010, and received the "Experienced researcher" award from Humboldt Foundation of Germany for his outstanding research work in SAW technology. He joined the IOA-CAS as an associate professor of acoustical microsystems Lab. and as a professor in 2007 and 2011 respectively. His current research involves acoustic wave devices for sensing applications and wireless sensor, etc. Prof. Wang is the author or co-author of more than 50 papers in a refereed international journal, more than 40 communications in international conferences and over 10 patents.

Contents

**Preface IX** 

**Part 1 Optical Chemical Sensor 1** 

Chapter 2 **Optical Sensors Based on Opal Film and** 

Irina Kargapolova, Alexandr Kuchyanov, Vladimir Shelkovnikov and Alexandr Plekhanov

Chapter 3 **Some Methods for Improving the Reliability of Optical Porous Silicon Sensors 47**  Tanya Hutter and Shlomo Ruschin

> **Continuous Monitoring of Blood Gases in Adipose Tissue and in Vital Organs 63**  Merima Čajlaković, Alessandro Bizzarri, Gijs H. Goossens, Igor Knez, Michael Suppan,

Chapter 5 **Chemical Sensors Based on Photonic Structures 89**  Vittorio M. N. Passaro, Benedetto Troia, Mario La Notte and Francesco De Leonardis

Chapter 6 **Coumarin-Derived Fluorescent Chemosensors 121** 

Chapter 4 **Optochemical Sensor Systems for** *In-Vivo*

Ismar Ovčina and Volker Ribitsch

Hongqi Li, Li Cai and Zhen Chen

**Part 2 Chemical Sensor with Nanostructure 151** 

Chapter 7 **Surface-Functionalized Porous Silicon Wafers: Synthesis and Applications 153** 

Fahlman Bradley D. and Arturo Ramírez-Porras

Ivan Boldov, Natalia Orlova,

Chapter 1 **Optical Chemical Sensors: Design and Applications 3** 

Aleksandra Lobnik, Matejka Turel and Špela Korent Urek

**Silica Nanoparticles Modified with a Functional Dye 29** 

## Contents

#### **Preface XI**


	- **Part 3 Electrical Chemical Sensor 213**
	- **Part 4 Artificial Chemical Sensor 255**
	- **Part 5 Sensor Technology 277**

## Preface

With decades of vigorous research and development, various chemical sensors with excellent performance have been used successfully in areas such as clinical, environmental conservation and monitoring, disaster and disease prevention, and industrial analysis. A chemical sensor is an analyzer that responds to a particular analyte in a selective and reversible way, and transforms chemical information, ranging from the concentration of a specific sample component to total composition analysis, into an analytically useful signal. The chemical information mentioned above may originate from a chemical reaction by a biomaterial, chemical compound or a combination of both attached onto the surface of a physical transducer toward the analyte. Numerous literatures deal with the sophisticated research on chemical sensors by considering the sensor structure, techniques and response mechanism, and leading to quick response, low cost, small size, superior sensitivity, good reversibility and selectivity, and excellent detection limit. Hence, such kind of chemical sensor meets the requirement of practical application.

This book is an attempt to highlight current research advances in chemical sensors on the topics of health, environment, and industry analysis. It is composed of 15 chapters and divided into 5 sections according to the classification following the principles of signal transducer. The current trends, materials design, and principle of detection and monitoring in chemical sensor are introduced in details. Section 1 provides an introduction to optical chemical sensors, and descriptions on the analytical aspects of sensors. Some of the latest research progress regarding the sensor structure and response mechanism is discussed in this section. Section 2 reviews some research achievements of chemical sensor based nanostructure. Section 3 describes the electrical chemical sensor by utilizing conductive and oxide semiconductor materials, and Section 4 performs the chemical sensor trend relating to the artificial chemical sensor. Sensor technologies related to sensor performance improvement by utilizing physical vapor deposition techniques, statistical analysis of the chemical sensor data, and drift correction methods are discussed in Section 5.

It is my pleasure that this collection of up-to-date information and latest research progress on chemical sensor in this book will be of great interest to all those working on chemical sensors.

#### XII Preface

I would like to acknowledge the hard work and dedication of all the contributing authors. In particular, I would like to thank Ms. Ivana Zec, the publishing process manager of this book, for her great help in proposal collection, evaluation and manuscript editing.

> **Wang Wen, Ph.D.**  Professor Institute of Acoustics, Chinese Academy of Sciences Beijing, China, P. R.

**Part 1** 

**Optical Chemical Sensor** 

**1** 

*Slovenia* 

**Optical Chemical Sensors:** 

Aleksandra Lobnik1, Matejka Turel1 and Špela Korent Urek2

Optical sensors, or opt(r)odes, represent a group of chemical sensors in which electromagnetic (EM) radiation is used to generate the analytical signal in a transduction element. The interaction of this radiation with the sample is evaluated from the change of a particular optical parameter and is related to the concentration of the analyte (Blum, 1997). Typically, an optical chemical sensor consists of a chemical recognition phase (sensing element or receptor) coupled with a transduction element (Fig. 1). The receptor identifies a parameter, e.g., the concentration of a given compound, pH, etc., and provides an optical signal proportional to the magnitude of this parameter. The function of the receptor is fulfilled in many cases by a thin layer that is able to interact with the analyte molecules, catalyse a reaction selectively, or participate in a chemical equilibrium together with the analyte. The transducer translates the optical signal produced by the receptor into a measurable signal that is suitable for processing by amplification, filtering, recording,

Sensors that have a receptor part based on a biochemical principle are usually called biosensors. The selectivity and sensitivity provided by Nature have been utilized in such sensors, frequently by immobilizing the biologically active compounds, such as enzymes and immunoglobulins, within a receptor part of the sensor (Patel et al., 2010). An effective way of obtaining the biological selectivity is a combination of cell cultures, tissue slices,

Optical sensors can be based on various optical principles (absorbance, reflectance, luminescence, fluorescence), covering different regions of the spectra (UV, Visible, IR, NIR) and allowing the measurement not only of the intensity of light, but also of other related properties, such as lifetime, refractive index, scattering, diffraction and polarization (Jerónimo et al., 2007). As an example, a luminescent sensor can be constructed by associating a sensing element, which emits light when in contact with a specific analyte, with a photodiode, which converts the energy of the incident light into a measurable signal. Optical chemical sensors have numerous advantages over conventional electricity-based sensors, such as selectivity, immunity to electromagnetic interference, and safety while working with flammable and explosive compounds. They are also sensitive, inexpensive, non-destructive, and have many capabilities. Optrodes do not require a reference cell, as is

**1. Introduction** 

display, etc. (Gründler, 2007; Nagl & Wolfbeis, 2008).

organs and sometimes of whole living organisms with the transducer.

*1Universitiy of Maribor, Faculty of Mechanical Engineering,*

*2Institute for Environmental Protection and Sensors,* 

**Design and Applications** 
