Nanosensors: Physical, Chemical, and Biological,
It should come as no surprise that a rapidly developing area of research is the application of nanostructured materials to sensor performance, which is constrained by the sensor material’s surface properties. A plethora of books on nanoscale science and technology have been published in the past decade, and several contain chapters or sections that focus on sensing. Examples include Nanochemistry: A Chemical Approach to Nanomaterials by Geoffrey Ozin and André Arsenault (RSC, 2005) and Nanostructures and Nanomaterials: Synthesis, Properties, and Applications by Guozhong Cao and Ying Wang (2nd edition, World Scientific, 2011). Some texts have even been dedicated to the subject. They include Nanotechnology-Enabled Sensors by Kourosh Kalantar-zadeh and Benjamin Fry (Springer, 2008) and Biosensing Using Nanomaterials edited by Arben Merkoçi (Wiley, 2009).
In Nanosensors: Physical, Chemical, and Biological, Vinod Kumar Khanna has set himself the ambitious task of surveying the entire field—as implied by the subtitle. One challenge in writing a book that covers any fast-moving, multidisciplinary field is to strike the right balance between depth and breadth. That is particularly true for nanosensing, which brings together materials science, electrical engineering, physics, measurement science, information technology, chemistry, and biology and applies them to problems as diverse as health care, industrial process control, and environmental monitoring.
The book has some significant strengths. Among them are its comprehensive coverage and its use of illustrative calculations to enhance the more descriptive sections. The depth of presentation ranges from the basic high school level to discussions of recent research literature. The book’s most likely beneficiaries are researchers in either sensor technology or nanotechnology who want to see how the two fields complement each other and can be combined in new and interesting ways to tackle important applications.
Notwithstanding the questions at the end of each chapter, Nanosensors is certainly not a textbook. Its rather old-fashioned structure, lack of sidebars and glossary, somewhat cluttered layout, and a few unclear diagrams make the book less student friendly than most course texts. Even its distinctive question-and-answer features, which recur throughout the book and are of some pedagogical merit, break up the flow of the text and would have been better placed in sidebars.
The dilemma the author faces in balancing breadth and depth is nowhere better illustrated than in the opening chapters. They cover such topics as semiconductor electronics, organic chemistry, and cell biology, but at a level too cursory to be of much use either as an introduction for readers unfamiliar with those topics or as a refresher for readers with prior knowledge. At the other extreme, the treatment of scanning probe microscopies is quite detailed, as are some laboratory protocols—for example, for the synthesis of gold nanoparticles. Moreover, several of the topics treated at an elementary level early in the book are later discussed in greater depth, which makes it tricky to know the intended level of detail.
The bulk of the book is structured around modalities for sensing—mechanical, thermal, optical, and magnetic, but not electrical—and around the different types of molecular sensors. Inevitably, such a structure must be arbitrary, since molecular sensors are ultimately based on an underlying physical modality to generate the signal. Thus microcantilevers are introduced in the mechanical sensors chapter but then reappear in the nanobiosensors chapter in the context of surface modification and DNA analysis. Metallic nanoparticles, carbon nanotubes, and silicon nanowires similarly crop up at many places throughout the book; sometimes the discussion is of their fundamental physics and material properties and sometimes of their use in chemical or biological sensors. Because such important topics are scattered throughout, the book would have benefited from a more comprehensive index.
The final chapter, which looks at future trends in nanosensing, is useful: It highlights the breakthroughs in overcoming the limitations of conventional sensors and the remaining challenges in deploying the technology. Nanosensors may appeal to researchers who would benefit from a comprehensive text, and is better when read here and there than digested cover to cover.