Biosensing has been one of the hottest topic attracting scientific minds since long back. It is so as biological entities are very complex and are directly associated with the existence of a healthy environment. The design of biosensors also has witnessed significant changes in the recent past. Biosensors for applications as diverse as food quality estimation, environmental monitoring, and diagnosis of clinical and metabolic complications have come to the fore. Nanotechnology has bestowed some highly exciting ingredients for the improvement of sensing phenomenon. The use of diverse nanomaterials ranging from nanoparticles, nanotubes, nanorods, and nanowires has enabled faster detection and its reproducibility in a much better way. The unique properties of nanomaterials such as high electrical conductivity, better shock bearing ability, and the sensitive responses such as piezoelectric and versatile color based detection mechanisms are only the results of congregation of nanomaterial properties. This paper highlights the different types of biosensors based on different types of nanomaterials and their developmental and implicational aspects.

Bacterial strains resistant to antimicrobial treatments, such as antibiotics, have emerged as serious clinical problems, necessitating the development of novel bactericidal materials. Nanostructures with particle sizes ranging from 1 to 100 nanometers have appeared recently as novel antibacterial agents, which are also known as “nanoantibiotics”. Nanomaterials have been shown to exert greater antibacterial effects on Gram-positive and Gram-negative bacteria across several studies. Antibacterial nanofilms for medical implants and restorative matters to prevent bacterial harm and antibacterial vaccinations to control bacterial infections are examples of nanoparticle applications in the biomedical sectors. The development of unique nanostructures, such as nanocrystals and nanostructured materials, is an exciting step in alternative efforts to manage microorganisms because these materials provide disrupted antibacterial effects, including better biocompatibility, as opposed to minor molecular antimicrobial systems, which have short-term functions and are poisonous. Although the mechanism of action of nanoparticles (NPs) is unknown, scientific suggestions include the oxidative-reductive phenomenon, reactive ionic metals, and reactive oxygen species (ROS). Many synchronized gene transformations in the same bacterial cell are essential for antibacterial resistance to emerge; thus, bacterial cells find it difficult to build resistance to nanoparticles. Therefore, nanomaterials are considered as advanced solution tools for the fields of medical science and allied health science. The current review emphasizes the importance of nanoparticles and various nanosized materials as antimicrobial agents based on their size, nature, etc.

The increased advancement in nanosciences in recent times has led to fascinating innovations. It has potential applications for altering the structural, surface, and physicochemical properties of nano-ranged metamaterials. The adaptable optical, structural, and surface characteristics of the nanoscopic regimes enhance the quality of integrated nanodevices and sensors. These are further used in optoelectronics, biomedicines, and catalysis. The use of nanomaterials for constructing nano-biosensors and various other organic and inorganic functional nanomaterials is quite promising. They have excellent electronic and surface-to-volume reactivity. Their various applications include metal and metal-oxides-based nanoparticles, clusters, wires, and 2D nanosheets as carbon nanotubes. More recently, hybrid nanomaterials are being developed to regulate sensing functionalities in the field of nanomedicine and the pharmaceutical industry. They are used as nano-markers, templates, and targeted agents. Moreover, the mechanical strength, chemical stability, durability, and flexibility of the hybrid nanomaterials make them appropriate for developing a healthy life for humans. This consists of a variety of applications, such as drug delivery, antimicrobial impacts, nutrition, orthopedics, dentistry, and fluorescence fabrics. This review article caters to the essential importance of nanoscience for biomedical applications and information for health science and research. The fundamental characteristics and functionalities of nanomaterials for particular biomedical uses are specifically addressed here.

Nanomaterials have gained huge applications ever since their discoveries, especially in the field of electronics, medicine, research, and environmental cleanup. Nanomaterials have a high surface area‐to‐volume ratio along with high surface energies making them suitable for such wide applications. Carbon nanotubes (CNTs) and carbon nanocomposite (CNC) materials are remarkable nanomaterials that have become the backbone of most industries these days. Both materials have gained huge attention in the last decade by the scientific community. CNTs come in two variants, i.e., single‐walled CNTs (SW‐CNTS) and multiwalled CNTs (MW‐CNTs). Due to their wider applications, CNT synthesis is currently emerging with the advancement in technology. Currently, CNTs are being synthesized by chemical as well as physical approaches. The current review article focuses on the vital research and application for the synthesis of CNTs depending on the quality of the nanotube materials. Controlled routes to their organization and assembly are also discussed in detail over here. The aim is to provide recent advances in the synthesis methods, of CNTs, their current applications, future applications, and the potential of agrowaste and industrial waste for the synthesis of CNTs and nanomaterials.

Aim: We report synthesis of capped gold nanoparticles (C-AuNPs) of ≈20–30 nm by reducing HAuCl4 with flower and leaf extracts of Ocimum tenuiflorum, leaves of Azadirachta indica and Mentha spicata and peel of Citrus sinensis plants. Methods: Atomic force microscopy (AFM) and transmission electron microscopy (TEM) determined their size, shape and topographical structures. The C-AuNPs with UV-Vis spectrophotometer produced a maximum absorption within 530–535 nm wavelengths. Their Fourier transform IR stretching frequencies, from 450 to 4000 cm-1, have inferred HAuCl4 reduction to Au. Results: The 512 and 600 μgml-1 C-AuNP MICs were expressed on antimicrobial strains Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumoniae, respectively. Conclusion: The chosen plant extracts have reduced the Au3+ to Au0 with simultaneous in situ capping with bacteria inhibiting activities. Green routes for C-AuNP synthesis could be an asset for several other biomedical and bioengineering applications. Lay abstract Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumoniae are pathogenic bacteria that can be very dangerous for humans. Their growth is inhibited by gold nanoparticles (AuNPs) capped with chemical agents from the flowers and leaves of Ocimum tenuiflorum, leaves of Azadirachta indica and Mentha spicata and peel of Citrus sinensis. Capped AuNPs expressed higher antibacterial activities as compared with Ag, Cu and Se metallic nanoparticles obtained by chemical reductions contrary to green routes. Capped AuNPs synthesized through green routes could also be an asset for several other biomedical applications.