Recent Progress and Prospect of Metal-Organic Framework-Based Nanozymes in Biomedical Application.

A nanozyme is a nanoscale material having enzyme-like properties. It exhibits several superior properties, including low preparation cost, robust catalytic activity, and long-term storage at ambient temperatures. Moreover, high stability enables repetitive use in multiple catalytic reactions. Hence, it is considered a potential replacement for natural enzymes. Enormous research interest in nanozymes in the past two decades has made it imperative to look for better enzyme-mimicking materials for biomedical applications. Given this, research on metal-organic frameworks (MOFs) as a potential nanozyme material has gained momentum. MOFs are advanced hybrid materials made of inorganic metal ions and organic ligands. Their distinct composition, adaptable pore size, structural diversity, and ease in the tunability of physicochemical properties enable MOFs to mimic enzyme-like activities and act as promising nanozyme candidates. This review aims to discuss recent advances in the development of MOF-based nanozymes (MOF-NZs) and highlight their applications in the field of biomedicine. Firstly, different enzyme-mimetic activities exhibited by MOFs are discussed, and insights are given into various strategies to achieve them. Modification and functionalization strategies are deliberated to obtain MOF-NZs with enhanced catalytic activity. Subsequently, applications of MOF-NZs in the biosensing and therapeutics domain are discussed. Finally, the review is concluded by giving insights into the challenges encountered with MOF-NZs and possible directions to overcome them in the future. With this review, we aim to encourage consolidated efforts across enzyme engineering, nanotechnology, materials science, and biomedicine disciplines to inspire exciting innovations in this emerging yet promising field.

Clinical implications and electrochemical biosensing of monoamine neurotransmitters in body fluids, in vitro, in vivo, and ex vivo models.

Monoamine neurotransmitters (MNTs) belong to one of the most important groups of neurotransmitters in the central nervous system. They play crucial role in functioning of cardiovascular, renal, and hormonal systems along with establishing human brain-body integration. Abnormal level of MNT is associated with numerous psychotic (schizophrenia, depression, dementia, etc.) and neurodegenerative diseases (Alzheimer's, Parkinson's, Huntington's disease, etc.), therefore their sensitive and robust detection is of great clinical significance. Electrochemical detection (ECD) techniques have been paving the path in this direction, for more than four decades now. Keeping the immense importance of MNTs in mind, this review has been formulated to describe fundamentals of MNTs followed by their clinical significance in neuroscience. Herein, we have emphasized on the ECD of MNTs, in various matrices reported till date. In order to provide information on ECD of MNTs in clinically comparable systems, we have included a comprehensive discussion on sensor design and its analytical performance towards analyzing MNTs in the in vitro, in vivo, and ex vivo models. An extensive table is also incorporated to provide better understanding of the role of MNTs in various clinical conditions. Furthermore, this review briefly discusses the challenges faced with EC sensing techniques and loopholes present in current research works. Apart from this, three extended tables are also included in this review, to provide an insight into the amount of work done in ECD of MNTs in last ten years (2008-2018). These tables comprehensively discuss sensor fabrication strategies for determining MNTs in various matrices and models along with their mode of detection and analytical performance.

Evolving trends in bio/chemical sensor fabrication incorporating bimetallic nanoparticles.

Biosensor designing took a giant leap in its path of evolution after its merger with a wing of nanotechnology. Dramatic properties like high surface area to volume ratio, enhanced chemical and optical properties of nanoscale materials have revolutionized sensor technology in terms of their analytical performance. Many metallic nanoparticles (MeNPs) like gold, silver, platinum, palladium nanoparticles, etc. have been tremendously exploited for improving sensor performance. Over the years, there has been slow but steady shift in nanoscience research with an aim to explore composite MeNPs like bimetallic, trimetallic nanoparticles, etc. So far, these engineered nanoparticles are shown to possess multifunctional properties which are providing several advantages over monometallic nanoparticles (mono-NPs). As a result of these properties, composite MeNPs, particularly bimetallic nanoparticles (BNPs), have sought the attention of sensor engineers and since then there has been rapid rise in the number of reports of sensors incorporating BNPs within a brief period of time. Keeping this pivotal fact in consideration, we have complied this review to give readers a clear insight in the possible ways BNPs can be synthesized that would render them to possess crucial characteristics desired for bio/chemical sensor fabrication and their applications. We have also discussed different characterization techniques that have been applied to investigate various properties of the BNPs along with a table that gives information on how each technique is different and in what ways they complement each other. Moreover, a comprehensive report on the incorporation of different BNPs in sensor fabrication for detection of hydrogen peroxide (H2O2), glucose, pesticides, nucleic acids, proteins, cancerous and bacterial cells has been described. The comparison of analytical performance of the biosensor design incorporating mono-NPs and BNPs, in terms of linear range (LR), limit of detection (LOD), sensitivity, and specificity, has also been discussed to show the importance of BNPs in sensing matrix.

Design of commercially comparable nanotherapeutic agent against human disease-causing parasite, Leishmania.

Nanotherapeutic agents (NTA) play a crucial role in clinical medicine, if their unique properties are well understood and well exploited. In this direction, we report synthesis and characterization of highly potent phytofabricated silver nanoparticles (AgNPs) using Sechium edule, which served the purpose of both reducing and capping agent. The designed AgNPs were characterized using UV-Vis spectroscopy, XRD, FTIR, HR-TEM, and TGA techniques. The formation of AgNPs was also confirmed using electrochemistry, which to the best of our knowledge has never been reported before for biosynthesized nanoparticles. The antileishmanial potential of AgNPs was examined on the clinical isolates of Leishmania donovani promastigote cells in an in vitro experimental setting. A dose dependent killing activity of the AgNP was observed with an IC50 value of 51.88 ± 3.51 µg/ml. These results were also compared using commercially available drug, miltefosine. Furthermore, the clinical applicability of AgNP, as antileishmanial agent was proven by testing them against normal mammalian monocyte cell line (U937). The results were statistically analyzed and no significant toxicity of AgNPs on the normal mammalian cells was observed.

Prospects of Nanostructure Materials and Their Composites as Antimicrobial Agents.

Nanostructured materials (NSMs) have increasingly been used as a substitute for antibiotics and additives in various products to impart microbicidal effect. In particular, use of silver nanoparticles (AgNPs) has garnered huge researchers' attention as potent bactericidal agent due to the inherent antimicrobial property of the silver metal. Moreover, other nanomaterials (carbon nanotubes, fullerenes, graphene, chitosan, etc.) have also been studied for their antimicrobial effects in order ensure their application in widespread domains. The present review exclusively emphasizes on materials that possess antimicrobial activity in nanoscale range and describes their various modes of antimicrobial action. It also entails broad classification of NSMs along with their application in various fields. For instance, use of AgNPs in consumer products, gold nanoparticles (AuNPs) in drug delivery. Likewise, use of zinc oxide nanoparticles (ZnO-NPs) and titanium dioxide nanoparticles (TiO2-NPs) as additives in consumer merchandises and nanoscale chitosan (NCH) in medical products and wastewater treatment. Furthermore, this review briefly discusses the current scenario of antimicrobial nanostructured materials (aNSMs), limitations of current research and their future prospects. To put various perceptive insights on the recent advancements of such antimicrobials, an extended table is incorporated, which describes effect of NSMs of different dimensions on test microorganisms along with their potential widespread applications.

Chitosan: An undisputed bio-fabrication material for tissue engineering and bio-sensing applications.

Biopolymers have been serving the mankind in various ways since long. Over the last few years, these polymers have found great demand in various domains which includes bio medicine, tissue engineering, bio sensor fabrications etc. because of their excellent bio compatibility. In this context, chitosan has found global attention due to its environmentally benign nature, biocompatibility, biodegradability, and ease of availability. In last one decade or so, extensive research in active biomaterials, like chitosan has led to the development of novel delivery systems for drugs, genes, and biomolecules; and regenerative medicine. Additionally, chitosan has also witnessed its usage in functionalization of biocompatible materials, nanoparticle (NP) synthesis, and immobilization of various bio-recognition elements (BREs) to form active bio-surfaces with great ease. Keeping these aspects in mind, we have written a comprehensive review which aims to acquaint its readers with the exceptional properties of chitosan and its usage in the domain of biomedicine, tissue engineering, and biosensor fabrication. Herein, we have briefly explained various aspects of direct utilization of chitosan and then presented vivid strategies towards formulation of chitosan based nanocomposites for biomedicine, tissue engineering, and biosensing applications.