Nanoconjugated materials as sensors in point-of-care diagnostic tools: Detection of small molecules and viruses

Diagnostic point of care (POC) tools have seen important advances through the many materials introduced to enhance and validate their wide range applications. One of the most used POC tools are paper-based colorimetric formats. These POC are generally based on the use of antibody-antigen pairs interaction for the detection. However, small molecules can be a challenge for these formats and drastically reduce the sensitivity of POC. Therefore, novel conjugated materials using nanoparticles, polymers, and other composites have been developed which helped to tackle the sensitivity issues and, by using these materials, the portable sensors became more trustworthy for the detection of small molecules. These materials can be sculpted into various nanostructures and networks such as nanovesicles and nanogels with high biocompatibility and tunability. These are regarded as promising tools in the current and future lab-on-chip devices due to their accessibility and ease to manufacturing. In addition, the application of portable biosensing devices is of great importance in large-scale screenings of viruses including the coronavirus SARS-CoV-2 (responsible for the COVID-19 pandemic) or road control (i.e., substance of abuse). These approaches were made more accessible using smartphone-assisted analyses allowing for the decentralization of diagnosis. In this chapter, we present the latest findings in the development of polymeric-based materials and biosensors aimed for the detection of viruses and small molecules of drug abuse through simplified approaches including colorimetric paper-based assays and electrochemical sensors. The use of nano-scaled bioconjugated materials became an integral component in sensing applications due to their various structural advantages in producing highly sensitive tools that rival bench-top instruments. New developments in material design opened the door for decentralized dispensation of medicines and public protection that allows effective onsite and point-of-care diagnostics. © 2023 Elsevier B.V.

Potential of siRNA in COVID-19 therapy: Emphasis on in silico design and nanoparticles based delivery.

Small interfering RNA (siRNA)-mediated mRNA degradation approach have imparted its eminence against several difficult-to-treat genetic disorders and other allied diseases. Viral outbreaks and resulting pandemics have repeatedly threatened public health and questioned human preparedness at the forefront of drug design and biomedical readiness. During the recent pandemic caused by the SARS-CoV-2, mRNA-based vaccination strategies have paved the way for a new era of RNA therapeutics. RNA Interference (RNAi) based approach using small interfering RNA may complement clinical management of the COVID-19. RNA Interference approach will primarily work by restricting the synthesis of the proteins required for viral replication, thereby hampering viral cellular entry and trafficking by targeting host as well as protein factors. Despite promising benefits, the stability of small interfering RNA in the physiological environment is of grave concern as well as site-directed targeted delivery and evasion of the immune system require immediate attention. In this regard, nanotechnology offers viable solutions for these challenges. The review highlights the potential of small interfering RNAs targeted toward specific regions of the viral genome and the features of nanoformulations necessary for the entrapment and delivery of small interfering RNAs. In silico design of small interfering RNA for different variants of SARS-CoV-2 has been discussed. Various nanoparticles as promising carriers of small interfering RNAs along with their salient properties, including surface functionalization, are summarized. This review will help tackle the real-world challenges encountered by the in vivo delivery of small interfering RNAs, ensuring a safe, stable, and readily available drug candidate for efficient management of SARS-CoV-2 in the future.

A comparative performance of antibacterial effectiveness of copper and silver coated textiles

During current COVID-19 crises, the antimicrobial textiles primarily those utilized in hospital by doctors and paramedical staff have become increasingly important. Thus, there is an unmet requirement to develop antimicrobial textiles for infection control and hygiene practices. Metallic nanoparticles exhibit great effectiveness towards resistant microbial species making them a potential solution to the increasing antibiotic resistance. Due to this, nanoparticles particularly copper and silver have become most prevalent forms of antibacterial finishing agents for the development of antimicrobial textiles. This review is mainly focused on the significance of copper and silver nanoparticles for the development of antimicrobial textiles. The comparative analysis of the antibacterial effectiveness of copper and silver nanoparticles as well as the possible physical and chemical interactions responsible for their antibacterial action are explained. The negative impact of pathogenic microbes on textiles and possible interactions of antimicrobial agents with microbes have also been highlighted. The significance of nanotechnology for the development of antimicrobial textiles and their applications in medical textiles domain have also been discussed. Various green synthesis and chemical methods used for the synthesis of Ag and Cu nanoparticles and their application on textile substrates to impart antimicrobial functionality have also been discussed. The various qualitative and quantitative standard testing protocols utilised for the antimicrobial characterization of textiles have also discussed in this review. The developed Cu and Ag coated textiles could be effectively applied in the field of hospital textiles for the preparation of antibacterial scrub suits, surgical gowns, panel covers, protective clothing, bedding textiles, coveralls, wound dressings, table covers, curtains, and chair covers etc. © The Author(s) 2022.

Functionalizing Gold Nanostars with Ninhydrin as Vehicle Molecule for Biomedical Applications

In recent years, there has been an explosion in Gold NanoParticle (GNP) research, with a rapid increase in publications in diverse fields, including imaging, bioengineering, and molecular biology. GNPs exhibit unique physicochemical properties, including surface plasmon resonance (SPR) and bind amine and thiol groups, allowing surface modification and use in biomedical applications. Nanoparticle functionalization is the subject of intense research, with rapid progress being made towards developing biocompatible, multi-functional particles. In the present study, the photochemical method has been done to functionalize various-shaped GNPs like nanostars by the molecules like ninhydrin. Ninhydrin is bactericidal, virucidal, fungicidal, antigen-antibody reactive, and used in fingerprint technology in forensics. The GNPs functionalized with ninhydrin efficiently will bind to the amino acids on the target protein, which is of eminent importance during the pandemic, especially where long-term treatments of COVID-19 bring many side effects of the drugs. The photochemical method is adopted as it provides low thermal load, selective reactivity, selective activation, and controlled radiation in time, space, and energy. © 2022, Avestia Publishing. All rights reserved.

MXene-Based Nanomaterials for Biomedical Applications: Healthier Substitute Materials for the Future

MXene-based nanomaterial is a revolution 2D material achieving outstanding scientific attention owing to its universal characteristics for different applications (such as electronic appliances, power production, sensors, drug transfer, and biomedical). Although, the cytotoxic consequences of MXene have a considerable circumstance. Thus, rigorous investigation of the biocompatibility of MXene is a crucial prerequisite, formerly the preface to the human biological approach. Literature reveals functional outcomes wherever MXenes are used in vitro and in vivo cancer representatives. It affects drug transfer methods, sensoring electrodes, and assisting mechanisms for photothermal treatment and hyperthermy techniques. In this review, the synthesis process (such as top-down and bottom-up approaches) and properties (such as mechanical, electrical, optical, oxidative/thermal stability, and magnetic) of MXene-based nanomaterials (NMs) are discussed. In addition, the different applications (such as tissue engineering, cancer theranostic, and other biomedical [such as drug delivery biosensors and surface-enhanced Raman spectroscopy substrates for biomedical applications], antiviral, and immunomodulatory properties against SARS-CoV-2) of MXene-based NMs are discussed in detail. Finally, the conclusion, existing challenges, and future outlooks are highlighted for more scope in this field.

siRNA Functionalized Lipid Nanoparticles (LNPs) in Management of Diseases.

RNAi (RNA interference)-based technology is emerging as a versatile tool which has been widely utilized in the treatment of various diseases. siRNA can alter gene expression by binding to the target mRNA and thereby inhibiting its translation. This remarkable potential of siRNA makes it a useful candidate, and it has been successively used in the treatment of diseases, including cancer. However, certain properties of siRNA such as its large size and susceptibility to degradation by RNases are major drawbacks of using this technology at the broader scale. To overcome these challenges, there is a requirement for versatile tools for safe and efficient delivery of siRNA to its target site. Lipid nanoparticles (LNPs) have been extensively explored to this end, and this paper reviews different types of LNPs, namely liposomes, solid lipid NPs, nanostructured lipid carriers, and nanoemulsions, to highlight this delivery mode. The materials and methods of preparation of the LNPs have been described here, and pertinent physicochemical properties such as particle size, surface charge, surface modifications, and PEGylation in enhancing the delivery performance (stability and specificity) have been summarized. We have discussed in detail various challenges facing LNPs and various strategies to overcome biological barriers to undertake the safe delivery of siRNA to a target site. We additionally highlighted representative therapeutic applications of LNP formulations with siRNA that may offer unique therapeutic benefits in such wide areas as acute myeloid leukaemia, breast cancer, liver disease, hepatitis B and COVID-19 as recent examples.

Advances on virucidal textile coatings

The COVID-19 pandemic has prompted an immediate response from scientists towards creating new technologies to mitigate the spread of coronavirus. Antimicrobial surfaces that repel or inactivate microorganisms stood out as a strategy to prevent viral transmission, leading to increased global demand for antiviral materials. Despite the advances in antimicrobial coatings, antiviral materials were little investigated until recently, demanding a systematic assessment of the state-of-the-art technologies in this field. This chapter assesses the advances in antiviral textiles, focusing on the interplay between the pathogen features and antiviral technologies. The main pathogenic viruses and their contamination mechanisms are briefly described, followed by a survey of the main antiviral agents, including nanoparticles, small organic molecules, and synthetic and natural polymers. Advances on finishing application are discussed in detail, highlighting the up-to-date antiviral fabric technologies. Finally, challenges to viral-inactivation agents on textiles are described, reinforcing the need for safe, scalable materials to protect people from biological threats. © 2022 Elsevier Ltd. All rights reserved.

A novel antibacterial and antifouling nanocomposite coated endotracheal tube to prevent ventilator-associated pneumonia.

BACKGROUND: The endotracheal tube (ETT) is an essential medical device to secure the airway patency in patients undergoing mechanical ventilation or general anesthesia. However, long-term intubation eventually leads to complete occlusion, ETTs potentiate biofilm-related infections, such as ventilator-associated pneumonia. ETTs are mainly composed of medical polyvinyl chloride (PVC), which adheres to microorganisms to form biofilms. Thus, a simple and efficient method was developed to fabricate CS-AgNPs@PAAm-Gelatin nanocomposite coating to achieve dual antibacterial and antifouling effects. RESULTS: The PAAm-Gelatin (PAAm = polyacrylamide) molecular chain gel has an interpenetrating network with a good hydrophilicity and formed strong covalent bonds with PVC-ETTs, wherein silver nanoparticles were used as antibacterial agents. The CS-AgNPs@PAAm-Gelatin coating showed great resistance and antibacterial effects against Staphylococcus aureus and Pseudomonas aeruginosa. Its antifouling ability was tested using cell, protein, and platelet adhesion assays. Additionally, both properties were comprehensively evaluated using an artificial broncho-lung model in vitro and a porcine mechanical ventilation model in vivo. These remarkable results were further confirmed that the CS-AgNPs@PAAm-Gelatin coating exhibited an excellent antibacterial capacity, an excellent stain resistance, and a good biocompatibility. CONCLUSIONS: The CS-AgNPs@PAAm-Gelatin nanocomposite coating effectively prevents the occlusion and biofilm-related infection of PVC-ETTs by enhancing the antibacterial and antifouling properties, and so has great potential for future clinical applications.

Biosensor Development

Research and development of biosensors has become the focus of many research disciplines due to the COVID-19 pandemic. The existence of biosensors has had a huge positive impact towards users due to their simple, rapid, cost effective, highly selective, and sensitive nature. The technology advancement has contributed to the improvement of healthcare systems and medicine. This chapter overviews the evolution of biosensors from the beginning until now. Three generations of biosensors with their commercialized products are highlighted. Besides that, a list of advance biomaterials which are bioresorbable and flexible are itemized. Then, the standard protocol of bio-sensing is emphasized.

Functionalized Self-Assembled Monolayers: Versatile Strategies to Combat Bacterial Biofilm Formation.

Bacterial infections due to biofilms account for up to 80% of bacterial infections in humans. With the increased use of antibiotic treatments, indwelling medical devices, disinfectants, and longer hospital stays, antibiotic resistant infections are sharply increasing. Annual deaths are predicted to outpace cancer and diabetes combined by 2050. In the past two decades, both chemical and physical strategies have arisen to combat biofilm formation on surfaces. One such promising chemical strategy is the formation of a self-assembled monolayer (SAM), due to its small layer thickness, strong covalent bonds, typically facile synthesis, and versatility. With the goal of combating biofilm formation, the SAM could be used to tether an antibacterial agent such as a small-molecule antibiotic, nanoparticle, peptide, or polymer to the surface, and limit the agent's release into its environment. This review focuses on the use of SAMs to inhibit biofilm formation, both on their own and by covalent grafting of a biocidal agent, with the potential to be used in indwelling medical devices. We conclude with our perspectives on ongoing challenges and future directions for this field.

Dual-Comb Biosensing for Rapid Detection of SARS-CoV-2

We demonstrated rapid detection of SARS-CoV-2 nucleocapsid protein antigen by dual-comb biosensing with surface modification of its corresponding antibody. A sensitivity close to that of RT-PCR was achieved, thanks to the use of active-dummy temperature compensation. © Optica Publishing Group 2022, © 2022 The Author(s)

Network polymers incorporating lipid-bilayer disrupting polymers: towards antiviral functionality

Designing a surface that can disinfect itself can reduce labor-intensive cleanings and harmful waste, and mitigate spread of surface borne diseases. Additionally, since COVID-19 is an airborne pathogen, surface modification of masks and filters could assist with infection control. Styrene-maleic acid (SMA) copolymers and their derivatives were shown to have lipid-bilayer disrupting properties, making them candidates as anti-viral materials. A series of network polymers with styrene-maleic acid-based polymers and control over polymer chain-length and composition were synthesized. All the polymers formed mechanically robust structures, with tunable Young's moduli on the order of MPa, and tunable swelling capability in water. The SMA-based bulk materials, containing a zwitterionic polar unit, showed excellent lipid disrupting properties, being up to 2 times more efficient than a 10% Triton solution. The highest performance was observed for materials with lower crosslink densities or shorter chain-lengths, with lipid disruption capability correlating with swelling ratio. Additionally, the material can capture the spike protein of SARS-CoV-2, with up to 90% efficiency. Both the lipid disrupting and spike protein capture ability could be repeated for multiple cycles. Finally, the materials are shown to modify various porous and non-porous substrates including surgical and KN95 masks. Functional network modified masks had up to 6 times higher bilayer disruption ability than the unmodified masks without inhibiting airflow. © 2022 The Royal Society of Chemistry.

Latest developments in the upconversion nanotechnology for the rapid detection of food safety: A review

Food safety has become a topic of global concern in the recent decades. The significant food safety incidents occur from time to time around the world, seriously threatening the public health and causing extensive economic losses. In particular, the occurrence of COVID-19 highlights the importance of the food safety for the public health. Therefore, there is an urgent need to establish a fast, simple, sensitive, and efficient method for the detection of food safety. In recent years, the upconversion (UC) nanotechnology has been widely used in the field of food detection. The UC fluorescence analysis technology possesses the advantages of ultra-sensitivity detection, non-invasiveness, light stability, etc., and has broad application prospects in the field of food safety. After cladding and surface modification, it can be combined with other substances through a variety of mechanisms, such as electrostatic interaction, thereby expanding its application in the food safety detection. Thus, overall, there is a vital need to evaluate and utilize the potential of UC nanoparticles in the field of rapid detection of food safety.

Use of Polymer Micropillar Arrays as Templates for Solid-Phase Immunoassays

We investigate the use of periodic micropillar arrays produced by high-fidelity microfabrication with cyclic olefin polymers for solid-phase immunoassays. These three-dimensional (3D) templates offer higher surface-to-volume ratios than two-dimensional substrates, making it possible to attach more antibodies and so increase the signal obtained by the assay. Micropillar arrays also provide the capacity to induce wicking, which is used to distribute and confine antibodies on the surface with spatial control. Micropillar array substrates are modified by using oxygen plasma treatment, followed by grafting of (3-aminopropyl)triethoxysilane for binding proteins covalently using glutaraldehyde as a cross-linker. The relationship between microstructure and fluorescence signal was investigated through variation of pitch (10-50 μm), pillar diameter (5-40 μm), and pillar height (5-57 μm). Our findings suggest that signal intensity scales proportionally with the 3D surface area available for performing solid-phase immunoassays. A linear relationship between fluorescence intensity and microscale structure can be maintained even when the aspect ratio and pillar density both become very high, opening the possibility of tuning assay response by design such that desired signal intensity is obtained over a wide dynamic range compatible with different assays, analyte concentrations, and readout instruments. We demonstrate the versatility of the approach by performing the most common immunoassay formats-direct, indirect, and sandwich-in a qualitative fashion by using colorimetric and fluorescence-based detection for a number of clinically relevant protein markers, such as tumor necrosis factor alpha, interferon gamma (IFN-γ), and spike protein of severe acute respiratory syndrome coronavirus 2. We also show quantitative detection of IFN-γin serum using a fluorescence-based sandwich immunoassay and calibrated samples with spike-in concentrations ranging from 50 pg/mL to 5 μg/mL, yielding an estimated limit of detection of ∼1 pg/mL for arrays with high micropillar density (11561 per mm2) and aspect ratio (1:11.35). © 2022. Published by American Chemical Society.

Recent Advances in Mucoadhesive Interface Materials, Mucoadhesion Characterization, and Technologies

Mucoadhesion is an extremely important field of adhesion science and the comprehensive understanding and modulation of mucoadhesion can lead to lifesaving materials and technologies. For instance, deadly cases of COVID-19 (SARS-CoV-2) cytokine storm are associated with viral adhesion and overproduction of mucus, which obstructs the airways. Mucin is the key polymeric compound that is known as a family of high molecular weight, heavily glycosylated proteins in epithelial tissues. Mucoadhesion can occur in many different ways such as receptor specific and charge interactions, covalent or noncovalent bonds. New mucin-mimic polymers that replicate its beneficial traits can prevent biofilm formation and biofouling not only in biotechnology but also in membrane technologies. This review addresses the latest understandings related to mucin's role in wet adhesion considering different physiological conditions and shows how this translates into interfacial polymer adhesion. Advances in mucoadhesion measurement techniques including the rheological aspects of polymer-mucin adhesive interactions are presented. Specific mucoadhesive systems are discussed such as hydrogel mucoadhesion, catechol/dopamine functionalization, and polymeric nanoparticles. This overview may expand the current understanding of mucoadhesion between soft materials but also contributes to elastocapillary phenomena in soft materials design and applications such as new membranes, drugs, pharmaceutical devices, and lubricated surfaces.

Generation of zinc ion-rich surface via in situ growth of ZIF-8 particle: Microorganism immobilization onto fabric surface for prohibit hospital-acquired infection.

Viruses/bacteria outbreaks have motivated us to develop a fabric that will inhibit their transmission with high potency and long-term stability. By creating a metal-ion-rich surface onto polyester (PET) fabric, a method is found to inhibit hospital-acquired infections by immobilizing microorganisms on its surface. ZIF-8 and APTES are utilized to overcome the limitations associated with non-uniform distribution, weak biomolecule interaction, and ion leaching on surfaces. Modified surfaces employing APTES enhance ZIF-8 nucleation by generating a monolayer of self-assembled amine molecules. An in-situ growth approach is then used to produce evenly distributed ZIF-8 throughout it. In comparison with pristine fabric, this large amount of zinc obtained from the modification of the fabric has a higher affinity for interacting with membranes of microorganisms, leading to a 4.55-fold increase in coronavirus spike-glycoprotein immobilization. A series of binding ability stability tests on the surface demonstrate high efficiency of immobilization, >90%, of viruses and model proteins. The immobilization capacity of the modification fabric stayed unchanged after durability testing, demonstrating its durability and stability. It has also been found that this fabric surface modification approach has maintained air/vapor transmittance and air permeability levels comparable to pristine fabrics. These results strongly advocate this developed fabric has the potential for use as an outer layer of face masks or as a medical gown to prevent hospital-acquired infections.

Surface Modification of Lipid-Based Nanoparticles.

There is a growing interest in the development of lipid-based nanocarriers for multiple purposes, including the recent increase of these nanocarriers as vaccine components during the COVID-19 pandemic. The number of studies that involve the surface modification of nanocarriers to improve their performance (increase the delivery of a therapeutic to its target site with less off-site accumulation) is enormous. The present review aims to provide an overview of various methods associated with lipid nanoparticle grafting, including techniques used to separate grafted nanoparticles from unbound ligands or to characterize grafted nanoparticles. We also provide a critical perspective on the usefulness and true impact of these modifications on overcoming different biological barriers, with our prediction on what to expect in the near future in this field.

Applications of Metal-Organic Frameworks as Drug Delivery Systems.

In the last decade, metal organic frameworks (MOFs) have shown great prospective as new drug delivery systems (DDSs) due to their unique properties: these materials exhibit fascinating architectures, surfaces, composition, and a rich chemistry of these compounds. The DSSs allow the release of the active pharmaceutical ingredient to accomplish a desired therapeutic response. Over the past few decades, there has been exponential growth of many new classes of coordination polymers, and MOFs have gained popularity over other identified systems due to their higher biocompatibility and versatile loading capabilities. This review presents and assesses the most recent research, findings, and challenges associated with the use of MOFs as DDSs. Among the most commonly used MOFs for investigated-purpose MOFs, coordination polymers and metal complexes based on synthetic and natural polymers, are well known. Specific attention is given to the stimuli- and multistimuli-responsive MOFs-based DDSs. Of great interest in the COVID-19 pandemic is the use of MOFs for combination therapy and multimodal systems.

Applications of electrospraying in biosensing, diagnostics, and beyond

Worldwide, diseases have rapidly grown as challenging problems that require the development and innovation of biosensing and diagnostic systems. In response to the current COVID-19 crisis, the needs for massive testing are being pushed harder than ever, urging scientists and engineers to search for diagnostic tools that can quickly and effectively detect and prevent the spread of the coronavirus. One technical candidate, electrospray (E-spray), appears to be promising for aiding these efforts mainly by its simple, flexible setup, environmentally friendly process, as well as low cost. Moreover, E-spray process enables activity retention of biomolecules and high-throughput productions of several functional and sensitive micro-/nanoscale structures that can significantly improve biosensor performance. Herein, we provide up-to-date developments of E-spray in biosensing and diagnostics, starting with a short introduction about E-spray and biosensor, followed by the uses of E-spray in biochips fabrications, in tailoring of biosensor surfaces, as well as in productions of sensory particles and other biosensing systems. Then, we discuss limitations, challenges of the technique, and eventually end this chapter with conclusion and outlook. © 2021 Elsevier Inc.

Specific Chemical Modification of Nanohole Edges in Membrane Graphene for Protein Binding

The vital role of biosensors in our lives is steadily increasing due to their wide range of applications. As part of our striving efforts to develop affordable and highly sensitive biosensing technologies, we present here the successful chemical modification of-and biological molecule attachment to-holes' edges formed in a sheet of graphene, named nanomembrane graphene (NMG). This work complements our previous work, which showed that NMG could be used as a mid-IR biosensor, in which it becomes essential to overcome the challenge of the specific chemical modification of the holes' edges. In this work, we formed the NMG on reduced graphene oxide (rGO) layer using Au nanoparticles (Au NPs) and nano-islands (Au NIs). The formation methods were optimized by applying a matrix of variable concentration, size, and deposition time, as well as by chemical modification of substrate. The optimum scenarios were defined as having an extremely thin rGO layer, Au NPs, or NIs with size and center-to-center distance of 20-35 and 40-60 nm, respectively, and to have weak interaction between the metal and the substrate to allow etching leading to the formation of holes. The chemical groups at the edges were investigated to define the best method to attach biological molecules to them. Finally, we demonstrated the successful measurement of the binding between SARS-CoV-2 spike protein and its antibody (ACE2);real-time binding measurements revealed an affinity constant of 0.93 × 109 M-1. We consider these results important as they demonstrate a new route to a low-cost and high-sensitivity biosensor. © 2022 American Chemical Society.