Nanomaterials for Healthcare, Energy and Environment

Riding on their size tunable properties, “Nanomaterials” have emerged as darling materials of 21st century for plethora of practical applications including optical. The nonlinear optical properties and optical emission of nanomaterial’s, enhances with the decrease in particle size due to the “quantum confinement effect.” Therefore, the quantum mechanical effects emerge at the nanoscale which ultimately dictates the optical properties of nanomaterials. This book chapter will delineate the conceptual basis of optical applications of nanomaterials, subject to their size and material specific optical properties, including examples for conceptual demonstration. Considering the broad width of applications this book chapter is particularly focussed on biosensing and photovoltaic applications of nanomaterials.

Bacterial infections have become a major concern worldwide and is the center of genuine research efforts towards development of the functional system against microbial attachment. Sometimes infection associated issues become life-threatening for the patient due to bacterial growth within a biofilm matrix. These bacterial accumulation leads to inefficient use of conventional antibiotics and this fact emphasizes the development of new treatment strategies for the infection control. Various class of bioactive agents such as metal nanoparticles (NPs), antibiotics, herbal components and essential oils are available for this wide antimicrobial spectrum against all type of microbes. Despite the fact, each category of the bioactive agents has limitations such as lack of binding ability of metal NPs, bacterial resistant, low bioavailability and hydrophobicity of the agents. However, the most crucial challenge in front of researchers is the modification of bioactive agents and reduces their toxicity while using as biomaterials. Designing bioactive agents within nanomaterial confinement provides broad prospects to develop functional NPs which may be bonded to any biomaterial surface through nanogel functionality, either coated or blended with polymeric substrates/surfaces and make them antimicrobial. The aim of this book chapter is to present the current perspective, approaches and challenges on the design of functional and bioactive nanomaterials with diverse functionality, their bioactivity against a wide spectrum of microbes so that it leads to the development of bioactive materials for human healthcare.

Metal oxide nanostructures have recently garnered much recognition because of their exceptional electrical, optical and molecular properties that provide a fascinating platform for the development of biosensors. Till recent years, various methods and techniques such as chemical precipitation, electrodeposition and hydrothermal treatment have been utilised to fabricate metal oxide-based biosensors with high sensitivities and low detection limits. However, a number of these fabricated devices are irreversible and have low sensitivities. Therefore, more efficient and reliable biosensing technologies need to be developed. Biosensors are usually defined as an analytical equipment that consists of a biological recognition component integrated to a transducer and signal processing unit that converts, amplifies and displays biochemical activity into a measurable signal. The goal of this bioelectrical combination is to detect pathogenic and physiological molecules in the food or body for the early detection as well as treatment of diseases using the high sensitivity and selectivity of biological sensing. We review here some of the main strategies used in the fabrication of metal oxide nanostructures, including the advancements in biosensors based on metal oxides and evaluate their properties with the aim of motivating greater interest in improving the development of biosensors for medical diagnosis.

Nanoparticles have revolutionized the field of nanotechnology, owing to their specialized characteristics. The immense use of nanoparticles in various fields has led to the great demand in terms of production as well as the fabrications methods. Apart from conventional methods, the use of environmental friendly methods had gained much impetus, particularly, using biological material, including plant extracts. The obtained metals based nanoparticles are applied in innumerable areas including drug discovery, antibacterial and DNA cleaving agents, while as DNA cleaving ability of nanoparticles is to be explored extensively. The various nanoparticles generated have been characterized by different spectroscopic, optical and thermal techniques to establish their precise structure and size. Thus, this chapter reports the importance of nanotechnology in the form of nanoparticles based on their various modes of synthesis, their biological significance in terms of targeting microbes and DNA.

The reduction of silver metal through the headway of nanotechnology results in the production of silver nanoparticle (AgNP). It is an apparent metallic nanoparticle widely recognized in nanotechnology for its application in various platforms. Physical, chemical and biological methods have been studied and developed in the past decade to synthesize crystalline AgNP. Among these three, biological synthesis known as green synthesis has been extensively accepted as the most eco-accommodating and an efficient technique for the production of AgNP. Biological method consumes bio-reducing agents present in the bio-extract used for the synthesis of AgNP, such as microorganisms (bacteria and fungi) and plants. Extract from the part of the plant such as, stem, leaf, flower and bark is utilized as bioreducing agent, where its extractions ready to incorporate AgNP. Besides, bioreducing agents/stabilizing agents, commonly known as capping agents present in the biological extraction for the green synthesis of AgNP omits the consumption of additional chemical agents. The size and structure of AgNP from biosynthesis could be portrayed by electron microscopes and structural analysis. In the present chapter, the biosynthesized AgNPs from various biological extractions were presented with their significant application as antimicrobial agent.

The challenge of providing clean drinking water is of enormous relevance in today’s human civilization, being essential for human consumption, but also for agriculture, livestock and several industrial applications. In addition to remediation strategies, the accurate monitoring of pollutants in water supplies, which most of the times are present at low concentrations, is a critical challenge. The usual low concentration of target analytes, the presence of interferents and the incompatibility of the sample matrix with instrumental techniques and detectors are the main reasons that render sample preparation a relevant part of environmental monitoring strategies. The discovery and application of new nanomaterials allowed improvements on the pretreatment of water samples, with benefits in terms of speed, reliability and sensitivity in analysis. In this chapter, the use of nanomaterials in solid-phase extraction (SPE) protocols for water samples pretreatment for environmental monitoring is addressed. The most used nanomaterials, including metallic nanoparticles, metal organic frameworks, molecularly imprinted polymers, carbon-based nanomaterials, silica-based nanoparticles and nanocomposites are described, and their applications and advantages overviewed. Main gaps are identified and new directions on the field are suggested.

In this article, we present an overview with the emphasis to highlight the basics of the origin of magnetism, size and shape effects on magnetic properties of materials and in particular the origin of nano magnetism which is also known as superparamagnetism when the size of the material particles lies between 1 and 30 nm. Besides this, a brief review of, various applications of the superparamagnetism in the areas like biosensors, data storage, drug delivery, and hyperthermia are discussed.

The rapid deterioration in water quality has become a global concern. Heavy metal ions are the most dangerous water pollutants for living organisms; hence, there is a necessity to remove these toxic pollutants from water. Traditional water purification methods are expensive and inefficient to provide adequate quality of water. In the past few decades, nanotechnology has gained remarkable attention in many areas including water purification processes. Nanomaterials have unique properties such as greater surface area, exceptional adsorption capability and high selectivity which make them more promising materials for removal of heavy metal ions, and other pollutants from water. Nanomaterials are capable of removing toxic metal ions with high efficiency and selectivity even at their lower concentration. This chapter gives an overview of various nanomaterials especially carbon nanomaterials (e.g., graphene and carbon nanotubes) for the removal of highly toxic metal ions such as arsenic (As⁵⁺), lead (Pb²⁺), cadmium (Cd²⁺), and mercury (Hg, Hg²⁺) from water. This chapter will also highlight the toxic effects and main barriers of nanomaterials in sustainable water treatment.

Since ages human kind is using natural and synthetic compounds for the cure of diseases. By large synthetic compounds have edged the natural compounds. Discovery of nanomaterials paved way for smart treatment of diseases which were considered incurable. Nanomedicine and nano drug delivery systems are developing at a very fast pace offering multiple benefits in the treatment of chronic human ailments such as cancer, HIV and many other diseases by target-oriented and site-specific delivery of medicines. A detailed importance of nanomaterials in drug delivery systems is given in this chapter. This chapter also presented a comprehensive scrutiny of the nanomaterials that are handy in targeted and site specific delivery of drugs, their synthesis and applications in the field of drug delivery.

Nanofluids are a new class of fluids engineered by dispersing nanometer-size structures (particles, fibers, tubes, droplets) in base fluids. In the last decade though the researcher has focused on the development in the field of nanofluids science with the emphasis on heat transfer but attention should also be keen on nanofluids preparation since the final properties of nanofluids are dependent on the stability of the dispersion. The current chapter focus on the recent progress on the study of nanofluids, such as the preparation methods, stability of nanofluids, methods to enhance the stability for nanofluids, the stability mechanisms of nanofluids, and presents the broad range of current and future applications in various fields including energy and mechanical and biomedical fields. This chapter also identifies the opportunities for future research. In addition to this, the chapter also focuses on a new class of nanofluids termed as “Ionanofluids”. Ionanofluids represent a new and innovative class of heat transfer fluids that encompass multiple disciplines like nanoscience, mechanical, and chemical engineering. This ionanofluids exhibit enhanced thermal properties compared to their base ionic liquids (ILs) which further increase with increasing concentration of carbon nanotubes (CNTs) as well as fluid temperature to some extent. This chapter concludes that ionanofluids (INFs) show great promises to be used as innovative heat transfer fluids and novel media for the exploitation of green energy technology.