The death caused by multidrug-resistant pathogens is increasing day by day, and it needs special attention due to the challenges faced by the world health care systems. Hence, there is an urgent need to develop novel materials for antimicrobial and drug delivery applications due to the emergence of multidrug-resistant microbial pathogens. The innovations in polymer nanotechnology have paved the way to explore their applications in biomedical and other industrial sectors. Two-dimensional (2D) materials are ultrathin nanomaterials that receive great attention due to the degree of anisotropy, a higher surface area, antimicrobial activity, and a drug-carrying capacity. These easily tunable materials can be functionalized with any material of interest that makes them superior to others. The polymer nanocomposites based on 2D materials can have significant potential in drug delivery and antimicrobial applications. Hence, this review will give an overview of different types of 2D nanomaterials, their properties, their interaction with biological systems, their antimicrobial mechanisms, antiviral properties, 2D material-based viral detection, their interaction with surfaces, immunomodulating effect, biocompatibility, 2D materials and inflammation, polymer composites based on 2D materials, and their antimicrobial as well as biomedical applications.

Based on the current scenario, it is clear that the advanced and upcoming nanoinnovations in food applications can further open new possibilities in the betterment and improvement of food quality and preservation. Both inorganic (metal and metal oxides) and organic (carbohydrates, proteins, lipids) nanoparticles are applied in nanofoods and packagings for offering improved shelf life, providing antimicrobial protection and maintaining fresh quality of food. Nevertheless, many in vitro and in vivo studies have demonstrated that the inorganic nanoparticles pose potential threats to human health as they are exposed in higher concentrations for longer periods and are degraded and excreted in lower amounts. Today, researchers are more focused on the speedy development and applications of nanotechnology due to its attractive impact in every field. However, considering the sake of consumers, it is mandatory to provide a comprehensive information regarding the interface between nanoparticles and cells, tissues, and organisms, particularly in relation to possible hazards to human health. This chapter details on the possible routes of human exposure to nanoparticles, their potential adverse effects on human and environment, and the different mechanisms involved behind nanotoxicity. The chapter also provides information on the conventional and advanced in vitro and in vivo nanotoxicity risk assessment tests currently practiced.

The development and application of renewable materials is the call for the future. As a result, extensive research is focused on developing more biodegradable polymers from renewable resources. One of the most promising and easily available biodegradable polymers of natural origin is polylactic acid (PLA), but the poor physiochemical properties of PLA limit its application. Nanocellulose, a natural polymer produced from cellulose, has emerged as a promising reinforcement in PLA to strengthen its limitations. The various nanoforms of cellulose include nanocellulose, nanocrystalline cellulose or cellulose nanocrystals, nanofibrillated cellulose or cellulose nanofibers, and microbial cellulose or bacterial nanocellulose. Both PLA and cellulose composites find applications in all essential fields of human welfare such as medicine, engineering, and automotive industries, and till now, many commercial daily use commodities have been fabricated with these composites. This chapter mainly covers the individual applications of polylactic acid-based composites and cellulosic composites and also discusses the versatile application potentials of hybrid PLA/cellulose composites.

Edible packagings in the form of coatings and thin films are one among the leading interesting and attractive primary packaging approaches for optimization of food quality. Edible coatings/thin films are prepared from renewable natural biomaterials, such as polysaccharides, lipids, and proteins which can be applied directly on food products to improve their quality and shelf life. Edible packaging possesses the unique advantages of being edible along with the packed food, biodegradable, eco-friendly, and washable. Advanced research has shown that the incorporation of nanomaterials in edible films can make this venture more promising and efficient. Nanomaterials or nanocomposite-based edible films/coatings can offer better encapsulation of bioactive agents and confer controlled release of antioxidants, antimicrobials, nutraceuticals, and flavoring agents. Besides, edible nanocoatings/films can also lead to improvement of food functional aspects like sensory attributes, maintain natural appearance, as well as provide protection from microbial spoilage thereby preserving the food freshness. This chapter discusses about the general aspects of edible coating and edible nanocoating, various types of nano-based edible coating biomaterials used, methods of applying edible nanocoatings on fresh and processed foods, and the recent developments and successful applications in this area.

Polymer/clay nanocomposites have established a protuberant position in the food industry as effective food preserving and food packaging materials. Polymer/clay nanocomposites are composed of two phases; a continuous phase, which is the polymer matrix into which a dispersion phase, that is, nanofillers (clay or metallic nanoparticles) is mixed to obtain the desired physicochemical properties. This chapter provides a brief description on the various properties of polymer nanocomposites and adds a note on their different methods of preparation, such as in situ polymerization, solution dispersion/solvent casting and melt intercalation method. After preparation, the developed nanocomposites must be well characterized for better understanding the structure of nanocomposites and to check the effective dispersion of the nanofillers in it. This chapter provides a brief description on the various properties of polymer nanocomposites and adds a note on their different methods of preparation. The later section gives a detailed information on the morphological and physicochemical analytical techniques used for the characterization of polymer/clay nanocomposites with suitable examples.

Nanomaterials have so far earned huge acceptance due to its promising applications in food packaging industry. Most of the shortcomings of conventional packaging has been succeeded with the introduction of nanotechnology in the packaging sector. Nanotechnological interventions in packaging field with the development of antimicrobial nanocomposites shows promises in protecting food from microbial spoilage and extending food shelf-life for longer duration. Among the various nanomaterials applied in packaging materials, silver nanoparticles (AgNPs) has renowned as the best candidate with immense applications, because of its varied and unique features. Today, silver-based nanomaterials find varied applications in food packaging sector, which include functionalized packagings with antimicrobial and improved physicochemical properties; edible nanocoatings, which can protect and retain food freshness, and moreover, thermal resistant high performance packages. In spite of the increasing exploitation and acceptance of AgNPs in various food contact materials, the possible issues associated with its release into food has to be properly and carefully addressed.

Food packaging is considered as one of the most crucial elements in food industry, as it acts as a physical barrier and aids in food protection and preservation. Non-biodegradable petroleum derived polymeric materials are commonly used for this purpose, which there by impose huge environmental and economic concern regarding their generation, accumulation and disposal. Integration of nanotechnology with materials science has resulted in the `Nanocomposite technology' for engineering of polymers to develop the polymer nanocomposites. Polymer nanocomposites developed from biodegradable and sustainable natural polymers with much improved properties are considered as a better alternative to reduce the `white pollution'. This chapter discusses about the development, characterization, properties and food packaging applications of biodegradable polymer nanocomposites.

As the demand for ready-made food is increasing, it is necessary to develop effective food packaging materials with antimicrobial activity to ensure microbiological safety of food. For this, polyvinyl alcohol (PVA) based active food packaging material reinforced with silver nanoparticles (AgNPs) was prepared by solvent casting. Here, ginger rhizome extract was used as the reducing agent for the rapid in situ reduction of AgNO3 to AgNPs (gAgNPs) within the PVA matrix, under the influence of direct sunlight. Then the films were characterized by SEM, XRD, FTIR and UV-Vis spectrophotometry. Mechanical property analysis of PVA/gAgNP nanocomposite film showed its improved features when compared to neat PVA film. The presence of gAgNPs in the PVA/gAgNP film provided significant UV and light barrier properties together with profound antibacterial activity against the foodborne pathogen Salmonella Typhimurium and Staphylococcus aureus. Considering these excellent results, PVA/gAgNP film can expect to have promising food packaging application.

The increasing acceptance of ready to eat food generates demand on development of active and intelligent food packaging material. Even though many polymers have been used for the packaging, they have limitations for broad applications. Among the various polymers, Poly Vinyl Alcohol is a promising film forming polymer with highly flexible, emulsifying and adhesive properties. A variety of nano-fabrication techniques have already been reported to improve the mechanical and antimicrobial properties of PVA to exploit its wider applications. In the present study, starch-PVA based composite films incorporated with zinc oxide nanoparticles and phytochemicals were prepared by solvent casting technique. The films were characterized by XRD, FT-IR, UV–Vis spectrometry and SEM. The developed nanocomposite films were demonstrated to have enhanced water barrier, mechanical and antimicrobial properties. The unique features of the nanocomposite with its pH indication property demonstrated in the study indicate its potential usage in food packaging applications.

This study reports the development of biodegradable PVA-montmorillonite K10 clay nanocomposite blend films with in situ generated ginger extract mediated silver nanoparticles. Photo-assisted method using sunlight irradiation was adopted for the rapid and eco-friendly in situ generation of ginger extract mediated silver nanoparticles in the composite. FTIR, XRD and SEM analysis were conducted to confirm the generation of AgNPs. The nanocomposite blend film had clear antimicrobial activity against common food borne pathogens S. Typhimurium and S. aureus. It also had superior mechanical properties, water resistivity and light barrier ability compared to control films. Indoor soil burial test revealed the nanocomposite blend would degrade completely within 110 days. The nanocomposite blend film was then fabricated into novel packaging pouches and found to be highly efficient in reducing the microbial burden in chicken sausage samples, compared to control polyethylene pouches, signifying its potentiality in extending the shelf life of chicken meat products.

The study reports a one-step preparation of polyvinyl alcohol/boiled rice starch blend film fabricated with in situ generated silver nanoparticles (PVA/BRS/sAgNPs) formed in the presence of sunlight irradiation. The bionanocomposite appeared to have dark brown color with a characteristic surface plasmon resonance peak at 439 nm. Further characterization has confirmed the presence of physical interactions among the components PVA, BRS and sAgNPs. Compared to the control PVA, the nanocomposites showed improved mechanical and optical properties with decreased water sensitivity. Presence of boiled rice starch and sAgNPs were also found to influence the light transmittance of composite film. Moreover, PVA/BRS/sAgNPs film was found to have superior barrier property against environmental microorganisms. Biodegradation of the composite films was studied by indoor soil burial test and was assessed by visual appearance, weight loss and FTIR analysis. Interestingly, both the PVA/BRS and PVA/BRS/sAgNPs films proved to be biodegradable and hence have promising application as cost effective food packaging material with the latter having marked antimicrobial property.

Poly(vinyl alcohol) (PVA) is an excellent film forming polymer used for packaging applications, but it has weak barrier and mechanical properties. Hence improvement in material properties of PVA is expected to enhance its suitability as an ideal food packaging material. For the first time, this study reports the use of boiled rice starch as a blending agent to modify the physicochemical properties of PVA. The aim of the work was to develop montmorillonite (Mt)/PVA/boiled rice starch blend material reinforced with silver nanoparticles (AgNPs) for food packaging application. Highly cost effective method was used for the generation of AgNPs from AgNO3 by using rice starch as a reducing agent. The rapid in situ generation of AgNPs within the polymer matrix, under the influence of direct sunlight, as conducted in this study is a novel approach. The nanocomposite films prepared by solvent casting method were characterized by SEM, XRD, FT-IR and UV–vis spectroscopy analysis. Mechanical, optical, and barrier properties of the nanocomposite films further showed its excellent properties when compared to the neat PVA film. The nanocomposite also showed promising antimicrobial activity against foodborne pathogens Salmonella typhimurium and Staphylococcus aureus. Hence the results suggest the nanocomposite blend developed in the study to be an ideal material for food packaging application.

Green synthesized silver nanoparticles (AgNPs) have enormous applications. Hence, there is an increasing demand to explore diverse bioresources for AgNP fabrication to make the process more cost-effective and rapid as possible. Due to the abundantly present hydroxyl groups of rice starch, it provides ideal sites for metal ion complexation and thereby synthesis of nanoparticles with promising activity. So the study was designed to develop rapid, eco-friendly and cost-effective method for green AgNP synthesis using boiled rice water starch in the presence of sunlight irradiation. The starch-capped nanoparticles (sAgNPs) formed in the study were found to have the surface plasmon absorbance at 439 nm. The study showed optimum yield of sAgNPs when 25% rice starch was treated with aqueous 1 mM AgNO3 for 15 min in the presence of sunlight. Fourier transform infrared spectroscopy analysis provided mechanistic insight into the role of -OH groups of starch in the reduction of AgNO3 to sAgNPs. On further characterization by X-ray diffraction analysis, the sAgNPs were identified to have FCC crystal structure. At the same time, high-resolution transmission electron microscopic analysis showed majority of sAgNPs to have spherical morphology, and dynamic light scattering study revealed the average particle size as 36.3 nm. Further confirmation on presence of AgNPs was carried out by energy-dispersive X-ray spectroscopy. Moreover, the sAgNPs exhibited promising antibacterial activity against foodborne pathogens, Salmonella Typhimurium and Staphylococcus aureus.

Herein we report the green synthesis of silver nanoparticles (AgNPs) completed within a rapid time of 2 hrs using Zingiber officinale rhizome extract in presence of sunlight. Characterization of nanoparticles was carried out by UV-Vis spectroscopy, HR-TEM, XRD and FTIR. Under TEM analysis, the size of the biosynthesized AgNPs was found to be remarkably small with size range of 4 to 15 nm. The AgNPs also exhibited excellent antibacterial activity against Staphylococcus aureus and Escherichia coli. MIC and MBC was found to be 62.5 mu g/mL and 500 mu g/mL for S. aureus, 125 mu g/mL and 250 mu g/mL for E. coli respectively.

In spite of newer innovations and process improvements, catheter related infections still pose serious threat to hospitalized patients. Silver nanoparticles (AgNPs) are well demonstrated to have antibacterial properties and also have been implemented for surface fabrication of many indwelling medical devices. So, herein we sought to compare the performance of AgNPs generated through biogenic routes using bacteria and plant extract for their antibacterial and antibiofilm potential against biofilm forming Staphylococcus aureus. The biosynthesized AgNPs were characterized by UV- Visible spectroscopy, HR-TEM and EDS analysis. The antibacterial efficiency of the nanoparticles was detected by Disc diffusion assay, MIC and MBC analysis. The antibiofilm properties of the nanoparticles were also investigated. The antibacterial mode of interaction of both nanoparticles on the bacterium was analyzed by HR-TEM. Insight into mode of interaction and mechanism of antibacterial activity of both AgNPs showed them to have promises for surface fabrication of central venous catheters. No study has been conducted so far to compare the efficiency of two different biogenic AgNPs and this highlights the novelty of the current work. Though both AgNPs were observed to exhibit comparable activity in terms of bactericidal and antibiofilm, the mode of bacterial interaction and degree of damage caused was entirely different.

Coagulase negative staphylococci (CoNS) are nosocomial pathogens that cause indwelling medical device associated infections due to its biofilm forming potential and multiple antibiotic resistance. The current study focused on species identification, antibiotic resistance profile and molecular basis of biofilm formation and attachment of CoNS isolated from clinical samples. Along with this, molecular screening for mecA and newly identified surface colonization protein encoded by sasX gene was also conducted. S. epidermidis (n = 19, 47%) was identified as the most prevalent CoNS species and very interestingly two biofilm forming, mecA positive S. epidermidis isolates were found to carry all the biofilm associated genes screened in this study, which indicates its potential to form the strong biofilm. Another novel observation of the study is the detection of sasX gene in one biofilm positive S. epidermidis isolate. The study also identified one doxycycline resistant mecA positive, multidrug resistant S. haemolyticus isolate. In conclusion, the study signifies the existence of multiple biofilm related genes, multidrug resistance and the presence of sasX gene among clinical isolates of CoNS.

Development of antibacterial and antibiofilm surfaces is in high demand. In this study, nanocomposite of Poly (ε-caprolactone)/Cloisite 30B was prepared by the solvent casting method. The membranes were characterised by SEM, AFM, and FTIR. Evaluation of water uptake, antimicrobial, antibiofilm, and microbial barrier properties demonstrated a significant antimicrobial and antibiofilm activity against MTCC strain of Staphylococcus haemolyticus and strong biofilm positive Staphylococcus epidermidis of clinical origin at low clay concentrations. These membranes acted as an excellent barrier to the penetration of microorganism. These nanocomposites can have promising applications in various fields including packaging.