Piezoelectric Sensors (eBook)

Preface 9
Contents 11
Part A Physical Aspects of QCM- Measurements 13
Interface Circuits for QCM Sensors 14
1 Introduction 17
2 Crystals 18
3 Fundamentals of Oscillators 33
4 Sensor Interface Circuits 38
5 Examples for Sensor Interface Circuits 44
References 57
Studies of Viscoelasticity with the QCM 59
1 Introduction 62
2 Complex Resonance Frequencies 66
3 Assumptions of the Standard Model 69
4 Wave Equations and Continuity Conditions: The Mathematical Approach 71
5 The QCM as an Acoustic Reflectometer: The Optical Approach 75
6 Equivalent Circuits: The Electrical Approach 79
7 Relation Between the Frequency Shift and the Load Impedance 85
8 Layered Systems within the Small-Load Approximation 88
9 Perturbation Analysis 103
10 Concluding Remarks 109
Appendix A Derivation of the Butterworth–van Dyke Equivalent Circuit 110
References 117
Probing the Solid/Liquid Interface with the Quartz CrystalMicrobalance 120
1 Introduction 122
2 Effect of Thin Surface Films 126
3 Quartz Crystal Operating in Contact with a Liquid 129
4 Quartz Crystals with Rough Surfaces Operating in Liquids 139
5 Slippage at Rough Surfaces 152
6 Conclusion 154
References 156
Studies of ContactMechanics with the QCM 159
1 Introduction 160
2 Modeling with Discrete Mechanical Elements 161
3 Nonlinear Mechanics and Memory Effects 169
4 Continuum Models 172
5 Concluding Remarks 176
References 177
Part B Chemical and Biological Applications of the QCM 179
Imprinted Polymers in Chemical Recognition forMass- Sensitive Devices 180
1 Introduction 181
2 Mass-Sensitive Devices 182
3 Generating Selectivity 190
4 Exemplary Sensor Applications 195
5 Future Outlook and Perspective 214
References 215
Analytical Applications of QCM- based Nucleic Acid Biosensors 218
1 Introduction 218
2 DNA-Based QCM Sensors Based on the Hybridization Reaction 220
3 Application of QCM Sensors Based on the Hybridization Reaction 225
4 New Frontiers in Nucleic Acid-Based Piezoelectric Biosensors: Aptasensors 235
5 Conclusions 239
References 240
Piezoelectric Immunosensors 243
1 General Introduction 244
2 Piezoelectric Immunosensors 261
References 281
Specific Adsorption of Annexin A1 on Solid Supported Membranes: AModel Study 287
1 Solid Supported Membranes 288
2 Interaction of Annexin A1 with Membranes 294
3 Conclusions 306
References 307
The Quartz Crystal Microbalance in Cell Biology: Basics and Applications 309
1 QCM as an Emerging Tool in Cell Biology 310
2 Lessons from Cell Adhesion 312
3 Analyzing Confluent Cell Layers 323
4 Electrochemical QCM: New Options and New Insights 338
5 Outlook on QCM Applications in Cell Biology 341
References 343
Part C Applications Based on Advanced QCM- Techniques 345
Enzyme Reactions on a 27 MHz Quartz CrystalMicrobalance 346
1 Introduction 346
2 Enzyme Reactions on DNA 348
3 Enzyme Reactions on Glycans 359
4 Conclusions 372
References 372
The Quartz Crystal Microbalance and the Electrochemical QCM: Applications to Studies of Thin Polymer Films, Electron Transfer Systems, Biological Macromolecules, Biosensors, and Cells 375
1 Introduction to Piezoelectric Techniques and the Quartz Crystal Microbalance 376
2 Studying Thin Film Systems with the QCM 380
3 Electron Transfer Studies of Chemical and Polymer Systems with the EQCM 390
4 EQCM Use in Studying Biochemical Processes, Biomimetic Systems and in Creating Biosensors 402
5 Applications of QCM to Studies of Cell Behavior 413
6 Future Prospects 420
References 423
The QCM-D Technique for Probing Biomacromolecular Recognition Reactions 429
1 A Brief QCM History 430
2 QCM-D Technique for Biorecognition Studies 438
3 Conclusions and Outlook 449
References 450
Resonant Acoustic Profiling (RAP™) and Rupture Event Scanning ( REVS ™) 452
1 Resonant Acoustic Profiling 453
2 Rupture Event Scanning 470
References 479
Subject Index 483

Analytical Applications of QCM-based Nucleic Acid Biosensors (p. 211-212)

Abstract Recent advances in nucleic acid-based detection coupled to piezoelectric transduction will be reported here. The main aspects involved in the development of nucleic acid sensors are considered: the immobilization of the probe, the sample pretreatments (DNA extraction, amplification, denaturation of the amplified material), the sensitivity and specificity, etc.

These systems have been applied to different fields from environmental analysis to clinical diagnostics. Examples taken from different analytical problems will be reported. Another nucleic acid sensor, also based on the affinity between the analyte and the receptor immobilized on the surface, is reported as an example of the most recent trend in the field. This receptor, called aptamer, acts as capturing receptor for a molecule in solution, such as a protein. An aptasensor developed for a specific protein will be reported.

Keywords Biosensor · QCM · Nucleic Acids · Hybridization · Aptamers

1 Introduction

The first report on the direct detection of nucleic acid interactions based on the use of acoustic wave devices was provided by Fawcett et al. in 1988 [1]. They described a quartz crystal microbalance (QCM)-based biosensor for DNA detection by immobilizing single-stranded DNA onto quartz crystals and detecting the mass changes after hybridization. Since this early work, a number of articles have appeared employing similar procedures, resulting in microgravimetricmeasurements based on nucleic acids [2–5].

In general, when dealing with biosensing for this kind of application a few considerations are mandatory. First, the system should be specific and sensitive enough for the required application and should provide reproducible results. The system should have short analysis time and easy formats. Moreover, the sample pretreatment should be as little as possible, ideally absent. In this chapter, the main aspects related to piezoelectric sensing based on nucleic acids are considered and examples taken from different fields of application, from environmental analysis to clinical diagnostics, will be considered. A nucleic acid-based sensor consists of a nucleic acid immobilized on the transduction surface, which interacts with the analyte free in solution. Depending on the immobilized nucleic acid sequence and the relative interaction that drives the binding, different sensors can be distinguished. One based on the detection of the hybridization reaction can be developed by immobilizing a nucleic acid probe on the surface of the sensor to recognize the complementary sequence present in the sample solution. The hybridization reaction between the probe and the target sequence drives the biospecific interaction, which results in the formation of a double helix complex on the sensing surface with the detection of the specific sequence of interest. The interaction is based on the specific recognition between the two single-stranded DNA filaments leading to the formation of the DNA helix. The hydrogen bonds stabilize selectively the couples adenine–thymine (AT) and guanine– cytosine (GC).

In QCM-based sensing, the recognition is displaced as ameasurable shift in the resonant frequency. Ideally, the frequency shift is maximum with the fully complementary sequence and it is absent with non-complementary DNA. A typical profile of a QCM-based DNA sensor signal is reported in Fig. 1, where the addition of complementary sequences leads to the formation of the double helix and causes an increase in the mass loading at the sensor surface, recorded as a decrease in the frequency shift of the crystal. With QCM-based sensing it is then possible to detect, in real time and without the use of any label, specific target sequences characteristic of the DNA of interest as well as point mutations. This kind of QCM DNA sensor has been applied by this research group to the analysis of many different target sequences like genetically modified organisms (GMOs) [2] and bacteria detection [6, 7] in the field of food and environmental analysis, respectively. In clinical diagnostics application, the sensor has been used for the detection of point mutations such as the mutation occurring in the p53 oncogene, related to cancer research, diagnosis and prognosis [8].