Biosensors

An Introductory Textbook

Jagriti Narang, C.S. Pundir

• Publisher: Jenny Stanford Publishing
• Year: 2017
• ISBN:
  9781351645034
• Edition: 1
• Topic: Medicine
• Subtopic: Biotechnology in Medicine

Nanotechnology is a budding field and has a pivotal role in sensing. Nanomaterials exist in various forms such as nanoparticles, nanoclusters, nanobelts, and nanospheres. These nanomaterials act as sensing interfaces and immobilization surfaces for various biomolecules such as enzymes, DNA, and antigens. Therefore, the preparation and characterization of these nanoparticles play an important role in sensing devices.

This handbook has evolved from the authors' teaching and research experience in the field of nanoparticle biosensing. It encompasses protocols for the synthesis of various forms of metal oxide nanoparticles; study of the various characterizing techniques that help deduce the shape, size, and morphology of these nanoparticles; and applications of these nanoparticles in the field of biosensors. It presents voltammetry techniques such as cyclic, linear wave, wave pulse, and differential pulse voltammetry, throws light on the interactions of nanomaterials and biomolecules, and discusses microfluidic devices, which due to their unique capability of miniaturization fascinate many researchers. It is a practical and user-friendly textbook that introduces the various basic principles and practical information that will help undergraduate and advanced-level students and researchers understand the science behind nanoscale sensing.

Chapter 1

Nanomaterials

Jagriti Narang,^a Nitesh Malhotra,^b Chandra Shekhar Pundir,^c and Tulika Dhaiya^d

^aAmity Institute of Nanotechnology, Amity University, Noida-201313, India

^bAmity Institute of Physiotherapy, Amity University, Noida-201313, India

^cDepartment of Biochemistry, MD University, Rohtak-124001, India

^dDepartment of Biotechnology, Shoolini University, Solan-173229, India

[email protected]

1.1 Introduction

Nanotechnology is a wide and interdisciplinary area of research and development activity that has been rising worldwide since the last decade. Nanomaterials are the foundation of nanotechnology. Nanomaterials are materials that are characterized in the size range of 1–100 nm. A nanometer is one millionth of a millimeter, approximately 100,000 times smaller than the diameter of a human hair [1–4].

1.2 Occurrence of Nanomaterials

Some nanomaterials occur naturally. These materials are associated with the natural world (animal and mineral) without any engineering by human beings, such as nanoparticles, and evolved from natural erosion, volcanic activity, and clays. Nanoparticles are also dispersed in natural colloids such as milk and blood. By learning and gathering motivation from nature, biomaterials have been designed and engineered for many applications [5]. Engineered nanomaterials are already being used in many commercial products and processes. Nanoparticles can be found in sunscreens, cosmetics, sporting goods, stain-resistant clothing, tires, electronics, as well as in day-to-day activities. Nanomaterials are also employed in nanomedicine application such as for diagnosis, imaging, and drug delivery.

Nanomaterials have remarkable distinct properties that are normally not observed in their bulk counterparts. There are two most important properties that make them best in comparison to their bulk counterparts: large surface area and novel quantum effects [6–9]. An additional key benefit of nanomaterials is the enhancement of their fundamental properties such as magnetization, optical properties, melting point, and hardness [10–15] as compared to counter bulk materials without change in chemical composition.

1.3 Revolution in Nanomaterials

Nature has evolved many nanostructures such as skin, claws, beaks, feather, horns, spider silk, and lotus leaf. Nanoscaled smoke particles were formed during the use of fire by early humans. The scientific story of nanomaterials, however, began much later. One of the first scientific reports is the colloidal gold particles synthesized by Michael Faraday as early as 1857. Nanostructured catalysts have also been investigated for more than 70 years. By the early 1940s, precipitated and fumed silica nanoparticles were manufactured and sold in the USA and Germany as substitutes for ultrafine carbon black for rubber reinforcements [16, 17].

1.4 Classification of Nanomaterials

Nanomaterials have extremely small size, having at least one dimension of 100 nm or less. They are classified based on the number of dimensions, which are not confined to the nanoscale range (<100 nm): (i) zero-dimensional (0-D), (ii) one-dimensional (1-D),(iii) two-dimensional (2-D), and (iv) three-dimensional (3-D) [18](Fig. 1.1).0

Figure 1.1 Classification of nanomaterials: (a) 0-D spheres and clusters; (b) 1-D nanofibers, wires, and rods; (c) 2-D films, plates, and networks; (d) 3-D nanomaterials.

1.4.1 Zero-Dimensional

In 0-D materials, all dimensions are measured within the nanoscale (no dimensions are larger than 100 nm). Characteristic features of 0-D nanomaterial are as follows:

• They can be amorphous or crystalline.

• They can be single crystalline or polycrystalline.

• They can possess different shapes and forms such as nanotubes, dendrimers, and fullerenes.

• They can be metallic, ceramic, or polymeric.

1.4.2 One-Dimensional

In 1-D materials, two dimensions are restricted to the nanoscale and one dimension is restricted to the macroscale. One dimension leads to needle-shaped nanomaterials. Characteristic features of 1-D nanomaterials are as follows:

• They include nanotubes, nanorods, and nanowires.

• They can be amorphous or crystalline.

• They can be chemically pure or impure.

• They can be metallic, ceramic, or polymeric.

1.4.3 Two-Dimensional

In 2-D materials, one dimension is restricted to nanoscale and two dimensions are restricted to the macroscale. Two dimensions lead to plate-like shapes. Characteristic features of 2-D nanomaterials are as follows:

• These materials include nanofilms, nanolayers, and nanocoatings.

• They can be amorphous or crystalline.

• They can be made up of various chemical compositions.

• They can be deposited on a substrate.

• They can be embedded into the surrounding matrix material.

• They can be metallic, ceramic, or polymeric.

1.4.4 Three-Dimensional

In 3-D materials, none of the dimensions are confined to the nanoscale. Three dimensions lead to nanocrystalline structures. Characteristic features of 3-D nanomaterials are as follows:

• These materials can be dispersions of nanoparticles, bundles of nanowires, and nanotubes as well as multinanolayers.

• In bulk, they can be composed of a multiple arrangement of nanosized crystals with different orientations.

1.5 Importance of Nanomaterials

The principal advantage of nanoparticles is their size regime, i.e., their large surface-area-to-volume ratio. This feature of nanoparticles enables high surface reactivity with the surrounding surface, which is ideal for many applications such as photocatalysis or in the fabrication of sensing devices [19]. Nanomaterials also show the capability of varying their elementary properties such as magnetization, optical properties, and melting point relative to bulk materials with no change in their chemical composition. These materials have attracted great attention in recent years as they possess mechanical, electrical, optical, and magnetic properties: Ceramics with integrated nanomaterials are of meticulous concern because they show more ductility at elevated temperatures compared to the coarse-grained ceramics; nano-metallic powders have been used for the production of dense parts and porous coating; nanostructured metal clusters are involved in catalytic applications; nanostructured metal-oxide thin films are employed for gas sensors; and metal-oxide nanoparticles are employed for biosensing applications [20, 21]. Nanocrystalline structures are being employed in solar cells.

1.6 Synthesis and Processing of Nanomaterials

Synthesis of nanomaterials with stringent control over size, shape, and crystalline structure has become very important for the applications of nanotechnology in numerous applications such as catalysis, medicine, and electronics. Nanoparticles are basically synthesized through two approaches: top down and bottom up. In the top-down approach, the bulk solid is dissembled into smaller and smaller portions so that the resulting material comes in nanometer. The bottom-up approach involves assembling of atoms in solution to form the material in the nanometer range [22].

1.6.1 Synthesis of Metallic Nanoparticles

Various methods are available for the synthesis of metallic nanoparticles:

1.6.1.1 Sol–gel synthesis

The sol–gel process is a type of wet chemical process. This technique involves the conversion of a system from a colloidal liqui...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Table of Contents
• Preface
• 1. Nanomaterials
• 2. Synthesis of Individual Nanomaterials
• 3. Characterization Techniques
• 4. Fabrication of Sensors for Electrochemical Determination
• 5. Electrochemical Techniques
• 6. Biosensors for Serum Metabolites
• 7. Microfluidics: A Platform for Futuristic Sensors
• Index