Nanotechnology: Introduction and Basic Concepts


Nanotechnology is a fast-growing science of nanosized particle growth and consumption, measuring size in the nanometre range. Additionally, nanotechnology is the practice of systemically characterising, manipulating and arranging matter at the nanometre scale, which has brought about a revolution in science, technology, engineering, drug discovery and therapy. Nanotechnology includes a combination of various sciences, including not only medicine, but also physics, chemistry, biochemistry and molecular biology. It describes and deals with previously unexplored functional characteristics (optical, magnetic, electronic and catalytic) for scientific benefit (El-Sayed, 2001). The nanometre scale is around 1000 times smaller than structures that the human eye might see but still 1000 times bigger than an atom. In the recent era, advancements have been made in methods and techniques that deal and tackle with the nanoscale size range and are classified under nanotechnology. Nanotechnology is defined as the control or reconstruction of matter at atomic and molecular levels of approximately 1-100 nm size range and the science that underlies known as nanoscience (Jain, 2018a, 2018b; Joshi et al., 2019; Bhushan, 2016). Today, there are many operations that take a lot of time and are very costly too. Speedier and much cheaper therapies can be created using nanotechnology in the pharmaceutical industry. Nanotechnology encompassing various nanomaterials and nanocarriers such as nanoemulgel, nanocapsules, carbon nanotubes (CNTs), fullerenes, hyperbranched polymers, dendrimers. etc. is being explored for various applications in medicine and drug delivery to treat severe and fatal diseases such as visceral leishmaniasis, triple negative breast cancer, AIDS, refractory cancers, etc. (Khan et al., 2019; Ahmad et al., 2018; Cuneo et al., 2020; Huang et al., 2020; Fana et al., 2020). Nanotechnology is also being explored in personalised medicine and 3-D printing technologies (Afsana et al., 2019).

The highly contagious infectious respiratory disease COVID-19, caused by a novel coronavirus SARS- CoV-2, attained the global pandemic status in just few months, which started in late 2019. Currently, millions of people have been infected while counting deaths in lakhs worldwide and affecting almost all countries around the world with this viral infection till the writing of this chapter. It is necessary in this global crisis that the scientists and researchers working in the fields of technology, engineering, medicine, healthcare, public health, etc. should join hands to devise a treatment or preventive strategy to stop spread of this disease. Nanotechnology can also be investigated here to develop, formulate and design treatment and vaccine to fight/stop this disease. Nanomaterials and nanotechnology could be explored here on the basis of phenomena that they are being explored for targeting therapeutic agents selectively to cancer cells or infected cells to avoid harm to healthy cells. This phenomenon could be useful in the treatment/management/prevention of this pandemic COVID-19 (Chan. 2020; Sportelli et al., 2020; Jain, 2017; Ahmad et al., 2018).

The nanotechnology is affecting all the fields including healthcare and being explored extensively for various applications. Nanotechnology has led to some important innovations in different fields ranging from aircraft to healthcare and drug delivery to marine science and also has ability to be explored promisingly for fighting with sudden crisis such as COVID-19 pandemic which emerged in late 2019.

Nanotechnology in Biomedical/Healthcare/Pharmaceutical Science

Drugs normally function through the entire body before entering the site affected by the disease. With these pharmaceutical nanotechnologies, the medication may be delivered at a specific location that will make the therapy even more powerful and reduce the chances of side effects (Misra et al., 2010). Nanoparticles (NPs) have been defined as solid colloidal particles varying in dimensions from 10 to 400 nm (Figure 1.1). These NPs consist of macromolecular substances in which the reactionary agents (bioactives) have been encapsulated or dissolved or entrapped, or to which the active agent is attached or adsorbed (Muthu and Singh, 2009). Pharmaceutical nanotechnology, through early diagnosis, prediction, prevention, personalised treatments and medication, offers a novel strategy and advanced technology for cancer (Kalyankar et al., 2012). Early diagnosis and targeted therapy techniques are the key areas of research where nanotechnology can play an important role (Sutradhar and Amin. 2014). Fiber optic technology is used for

The size of nanoparticles compared with biologically related molecules and organisms. Reproduced with permission from (Gnach et al., 2014)

FIGURE 1.1 The size of nanoparticles compared with biologically related molecules and organisms. Reproduced with permission from (Gnach et al., 2014).

tracking diseases. Optical biosensors are used to measure physical parameters such as pH. blood supply volume, blood oxygen concentrations and radiation dosage. Next generation endoscopy can expand its ability from imaging to treatment and therapy using nanofibre technology (Quan and Zhang, 2015).

Nanomaterials and nanodevices are the two basic forms of pharmaceutical nanotechnology and play a key role in pharmaceutical drug delivery and other fields (Mohan and Varshney, 2012). Enormous surface areas and quantum effects are the two important factors that render nanomaterials some unique properties compared to other materials including drug targeting, intracellular drug deliver)', theranostic applicability, gene delivery, etc. Nanomaterials are made of biomaterials used in orthopaedic or dental implants or as scaffolds for tissue-based items. Their surface can be updated, or coatings may be developed which enhances biocompatibility with human cells. These are further graded into two forms, namely nanocrystal and nanostructural materials. Nanocrystals are ground in special mills, and the resulting drugs can be applied intravenously or bronchially through an inhaler as nanosuspensions. The small size increases the surface/volume ratio and the bioavailability of insoluble pharmaceutical materials (Clement et al., 2012; Malamatari et al., 2018). Nanosuspensions are colloidal submicron dispersions of condensed nanosized drug particles stabilised by polymers and surfactants. Nanosuspensions are formulated to increase the dissolution rate and mucoadhesion of poorly soluble drugs to increase their bioavailability on administration via routes such as oral, pulmonary, ocular, etc. Scientists have been exploring nanosuspensions for the delivery of BCS class II drugs, which are poorly water soluble. Recently, a nanosuspension of fluvoxam- ine, a selective serotonin reuptake inhibitor, which is commonly used as first line anti-depressant treatment for major depressive disorders, was prepared to improve its bioavailability. A nanosuspension of itraconazole, a broad spectrum anti-fungal drug, has been prepared and converted to inhalable and re-dispersible NPs for deep lung deliver)' by scientists. A mucoadhesive nanosuspension-based formulation of lorata- dine, an anti-histaminic anti-allergic drug, was prepared for nasal delivery with improved bioavailability (Tyagi and Madhav, 2020; Wan et al., 2020; Alshweiat et al., 2020; Villanueva-Martmez et al., 2020).

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