Risk assessment of selected pharmaceuticals on wildlife with nanomaterials based aptasensors.

Pharmaceuticals have improved human and veterinary health tremendously over the years. But the implications of the presence of pharmaceuticals in the environment on terrestrial, avian, and aquatic organisms are still not fully comprehended. The bioaccumulation and biomagnifications of these chemicals through the food chain have long-term effects on the wildlife. The detection and quantification of such pharmaceutical residues in the environment is a tedious process and quicker methods are needed. Aptasensors are one such quick and reliable method for the identification of pharmaceutical residues in the wildlife. Aptasensors are a class of biosensors that work on the principles of biological recognition of elements. The aptamers are unique biological recognition elements with high specificity and affinity to various targets. Their efficiency makes them a very promising candidate for such sensitive research. In this review, the pharmaceutical threats to wildlife and their detection techniques using aptasensors have been discussed.

Chitosan functionalized Halloysite Nanotubes as a receptive surface for laccase and copper to perform degradation of chlorpyrifos in aqueous environment.

Chitosan (CTS) functionalized Halloysite Nanotubes (HNT) have been used as receptive nano-supports for the grafting of copper (Cu) and laccase (Lac) for the degradation of chlorpyrifos. The developed nanocomposite Lac@Cu-CTS-HNT showed 83.4% Lac immobilization which was further characterized by TEM, SEM-EDX, FTIR, XRD, DSC and TGA. The chlorpyrifos degradation studies were performed under constant stirring for 24 h with both free enzyme and Lac@Cu-CTS-HNT and were analysed through HPLC. Percentage degradation of chlorpyrifos with the nanocomposite went as high as 97% for 50 µg/mL chlorpyrifos at neutral pH and room temperature. Variable pesticide and nanocomposite concentration, pH, and temperature studies for pesticide degradation were also performed, followed by reusability studies. The nanocomposite maintained its degradation ability at ~97% even at variable temperature and pH conditions. Reusability study was performed 5 times wherein the degradation percentage remained the same after 5 cycles (~<95%). Degradation kinetics were also performed for the nanocomposite in the presence and absence of the immobilized enzyme. Through this study, it is suggested that Lac@Cu-CTS-HNT can be a potential nano-catalyst for the degradation of chlorpyrifos in aqueous environment.

Nano-interfacial decoration of Halloysite Nanotubes for the development of antimicrobial nanocomposites.

In recent times, incorporation of Halloysite Nanotubes (HNTs) with various antimicrobial agents as interfacial materials between these nanotubes and pathogenic microorganisms, for the development of antimicrobial nanocomposites with enhanced antimicrobial activities has gained researcher's interest. The main benefits given by HNT to these nanocomposites include enhanced thermal and mechanical stability of the antimicrobial nanocomposites and also prolong durability and release of the antimicrobial agents in a sustained manner. The exceptional structure of these aluminosilicate minerals based nanotubes (hollow tubular lumen with huge surface area) and oppositely charged surface molecules assist in attaching various molecules on both, the internal surface as well as on the outer surface of these nanotubes. Other advantages of these clay-based minerals are their biocompatibility, non-toxicity, eco-friendly nature and their natural availability with affordable price, which also contribute in selecting them as supporting material for biological applications. Therefore, these clay-based nanotubes have been recently used for developing various antimicrobial nanocomposites. In this review, various antimicrobial nanocomposites developed through incorporation of HNT with myriad antimicrobial agents such as nanoparticles, metal ions, antibiotics, essential oils, biopolymers, phenolic compounds, surfactants and food preservatives as an interface between these nanotubes and microorganisms have been discussed. These antimicrobial nanocomposites could be synthesized in different forms (powder, film, nanocapsule and adhesive) which can be applicable in various fields such as food packaging, water decontamination, waste water management, healing of wounds, antimicrobial agents for surfaces, orthopedics and for the treatment of microbial infections.

Halloysite nanotubes as a nature's boon for biomedical applications.

The arena of biomedical science has long been in quest of innovative mediums for diagnostic and therapeutic applications. The latest being the use of nanomaterials for such applications, thereby giving rise to the branch of nanomedicine. Halloysite nanotubes (HNTs) are naturally occurring tubular clay nanomaterials, made of aluminosilicate kaolin sheets rolled several times. The aluminol and siloxane groups on the surface of HNT facilitate the formation of hydrogen bonding with the biomaterials onto its surface. These properties render HNT pivotal in diverse range of applications, such as in environmental sciences, waste-water treatment, dye removal, nanoelectronics and fabrication of nanocomposites, catalytic studies, as glass coatings or anticorrosive coatings, in cosmetics, as flame retardants, stimuli response, and forensic sciences. The specific properties of HNT also lead to numerous applications in biomedicine and nanomedicine, namely drug delivery, gene delivery, tissue engineering, cancer and stem cells isolation, and bioimaging. In this review, recent developments in the use of HNT for various nanomedicinal applications have been discussed.

Surface modified halloysite nanotubes: A flexible interface for biological, environmental and catalytic applications.

Halloysite Nanotubes (HNTs) are clay minerals that possess unique chemical composition and a tubular structure due to which, they have recently emerged as a potential nanomaterial for umpteen applications. Over the years, the myriad applications of HNT have been realized through the surface modification of HNT, which involves the modification of nanotube's inner lumen and the outer surface with different functional compounds. The presence of aluminum and silica groups on the inner and outer surface of HNT enhance the interfacial relationship of the nanotube with different functional agents. Compounds such as alkalis, organosilanes, polymers, compounds of biological origin, surfactants and nanomaterials have been used for the modification of the inner lumen and the outer surface of HNT. The strategies change the constitution of HNT's surface either through micro-disintegration of the surface or by introducing additional functional groups on the surface, which further enhances their potential to be used as a flexible interface for different applications. In this review, the different surface modification strategies of the outer surface and the inner lumen that have been employed over the years have been discussed. The biological, environmental and catalytic applications of these surface modified HNTs with such versatile interface in the past two years have been elaborately discussed as well.

Fabrication routes for one-dimensional nanostructures via block copolymers.

Nanotechnology is the field which deals with fabrication of materials with dimensions in the nanometer range by manipulating atoms and molecules. Various synthesis routes exist for the one, two and three dimensional nanostructures. Recent advancements in nanotechnology have enabled the usage of block copolymers for the synthesis of such nanostructures. Block copolymers are versatile polymers with unique properties and come in many types and shapes. Their properties are highly dependent on the blocks of the copolymers, thus allowing easy tunability of its properties. This review briefly focusses on the use of block copolymers for synthesizing one-dimensional nanostructures especially nanowires, nanorods, nanoribbons and nanofibers. Template based, lithographic, and solution based approaches are common approaches in the synthesis of nanowires, nanorods, nanoribbons, and nanofibers. Synthesis of metal, metal oxides, metal oxalates, polymer, and graphene one dimensional nanostructures using block copolymers have been discussed as well.

Multifarious applications of atomic force microscopy in forensic science investigations.

Forensic science is a wide field comprising of several subspecialties and uses methods derived from natural sciences for finding criminals and other evidence valid in a legal court. A relatively new area; Nano-forensics brings a new era of investigation in forensic science in which instantaneous results can be produced that determine various agents such as explosive gasses, biological agents and residues in different crime scenes and terrorist activity investigations. This can be achieved by applying Nanotechnology and its associated characterization techniques in forensic sciences. Several characterization techniques exist in Nanotechnology and nano-analysis is one such technique that is used in forensic science which includes Electron microscopes (EM) like Transmission (TEM) and Scanning (SEM), Raman microscopy (Micro -Raman) and Scanning Probe Microscopes (SPMs) like Atomic Force Microscope (AFM). Atomic force microscopy enables surface characterization of different materials by examining their morphology and mechanical properties. Materials that are immeasurable such as hair, body fluids, textile fibers, documents, polymers, pressure sensitive adhesives (PSAs), etc. are often encountered during forensic investigations. This review article will mainly focus on the use of AFM in the examination of different evidence such as blood stains, forged documents, human hair samples, ammunitions, explosives, and other such applications in the field of Forensic Science.