Amperometric hydrogen peroxide biosensor based on the immobilization of heme proteins on gold nanoparticles–bacteria cellulose nanofibers nanocomposite

Catalytic and biomedical applications of nanocelluloses: A review of recent developments

Nanocelluloses exhibit immense potential in catalytic and biomedical applications. Their unique properties, biocompatibility, and versatility make them valuable in various industries, contributing to advancements in environmental sustainability, catalysis, energy conversion, drug delivery, tissue engineering, biosensing/imaging, and wound healing/dressings. Nanocellulose-based catalysts can efficiently remove pollutants from contaminated environments, contributing to sustainable and cleaner ecosystems. These materials can also be utilized as drug carriers, enabling targeted and controlled drug release. Their high surface area allows for efficient loading of therapeutic agents, while their biodegradability ensures safer and gradual release within the body. These targeted drug delivery systems enhance the efficacy of treatments and minimizes side effects. Moreover, nanocelluloses can serve as scaffolds in tissue engineering due to their structural integrity and biocompatibility. They provide a three-dimensional framework for cell growth and tissue regeneration, promoting the development of functional and biologically relevant tissues. Nanocellulose-based dressings have shown great promise in wound healing and dressings. Their ability to absorb exudates, maintain a moist environment, and promote cell proliferation and migration accelerates the wound healing process. Herein, the recent advancements pertaining to the catalytic and biomedical applications of nanocelluloses and their composites are deliberated, focusing on important challenges, advantages, limitations, and future prospects.

Zwitterionic hydrogel for preserving stability and activity of oxidase enzyme for electrochemical biosensor

Enzymatic electrochemical biosensor is the most common analytical platform for medical diagnosis. To mimic the biological environment of the enzyme for maintaining the function of biosensor, zwitterionic hydrogels have been recognized as effective matrices for enzymatic immobilization. Herein, a zwitterionic hydrogel derived from a copolymer, poly[2-methacryloyloxyethyl phosphorylcholine (MPC)-co-N-methacryloyloxyethyl tyrosine methylester (MAT)] (PMM) was firstly applied as versatile coating to preserve stability and activity of oxidase enzymes, glucose oxidase (GOx) and lactate oxidase (LOx) for enzymatic electrochemical sensor. A screen-printed carbon electrode (SPCE) was sequentially coated with nitrogen-doped graphene (NDG), oxidase enzyme, and PMM mixed with Ru(II)bpy32+ and (NH4)2S2O8 followed by visible light irradiation for 3 min to induce PMM gelation. Electrochemical detection of glucose and lactate using the modified SPCE was performed via amperometry in the presence of hydrogen peroxide. The activity of both GOx and LOx immobilized on the modified SPCE was well maintained for 49 days at 87 and 80 %, respectively. Additionally, two different electrodes, a screen-printed graphene electrode (SPGE), and a screen-printed silver electrode (SPAgE), similarly modified gave the same satisfactory detection of spiked glucose and lactate in human plasma and sweat with 93-118 % recovery. This indicates the potential of the PMM hydrogel as a universal platform for preservation of enzymes which can be easily fabricated without the need for specific chemical modification of the electrode.

A comprehensive review on nanocomposite biomaterials based on gelatin for bone tissue engineering

The creation of a suitable scaffold is a crucial step in the process of bone tissue engineering (BTE). The scaffold, acting as an artificial extracellular matrix, plays a significant role in determining the fate of cells by affecting their proliferation and differentiation in BTE. Therefore, careful consideration should be given to the fabrication approach and materials used for scaffold preparation. Natural polypeptides such as gelatin and collagen have been widely used for this purpose. The unique properties of nanoparticles, which vary depending on their size, charge, and physicochemical properties, have demonstrated potential in solving various challenges encountered in BTE. Therefore, nanocomposite biomaterials consisting of polymers and nanoparticles have been extensively used for BTE. Gelatin has also been utilized in combination with other nanomaterials to apply for this purpose. Composites of gelatin with various types of nanoparticles are particularly promising for creating scaffolds with superior biological and physicochemical properties. This review explores the use of nanocomposite biomaterials based on gelatin and various types of nanoparticles together for applications in bone tissue engineering.

Opportunities for bacterial nanocellulose in biomedical applications: Review on biosynthesis, modification and challenges

Bacterial nanocellulose (BNC) is a natural polysaccharide produced as extracellular material by bacterial strains and has favorable intrinsic properties for primary use in biomedical applications. In this review, an update on state-of-the art and challenges in BNC production, surface modification and biomedical application is given. Recent insights in biosynthesis allowed for better understanding of governing parameters improving production efficiency. In particular, introduction of different carbon/nitrogen sources from alternative feedstock and industrial upscaling of various production methods is challenging. It is important to have control on the morphology, porosity and forms of BNC depending on biosynthesis conditions, depending on selection of bacterial strains, reactor design, additives and culture conditions. The BNC is intrinsically characterized by high water absorption capacity, good thermal and mechanical stability, biocompatibility and biodegradability to certain extent. However, additional chemical and/or physical surface modifications are required to improve cell compatibility, protein interaction and antimicrobial properties. The novel trends in synthesis include the in-situ culturing of hybrid BNC nanocomposites in combination with organic material, inorganic material or extracellular components. In parallel with toxicity studies, the applications of BNC in wound care, tissue engineering, medical implants, drug delivery systems or carriers for bioactive compounds, and platforms for biosensors are highlighted.

Recent Developments in Chemical Derivatization of Microcrystalline Cellulose (MCC): Pre-Treatments, Functionalization, and Applications

Microcrystalline Cellulose (MCC) is an isolated, colloidal crystalline portion of cellulose fibers, and it is a valuable alternative to non-renewable fossil-based materials. It is used for a large plethora of different fields, such as composites, food applications, pharmaceutical and medical developments, and cosmetic and material industries. The interest of MCC has also been driven by its economic value. In the last decade, particular attention has been driven to the functionalization of its hydroxyl groups to expand the field of applications of such biopolymer. Herein, we report and describe several pre-treatment methods that have been developed to increase the accessibility of MCC by breaking its dense structure allowing further functionalization. This review also collects the results that have appeared in the literature during the last two decades on the utilization of functionalized MCC as adsorbents (dyes, heavy metals, and carbon dioxide), flame retardants, reinforcing agents, energetic materials, such as azide- and azidodeoxy-modified, and nitrate-based cellulose and biomedical applications.

Review of Bacterial Nanocellulose-Based Electrochemical Biosensors: Functionalization, Challenges, and Future Perspectives

Electrochemical biosensing devices are known for their simple operational procedures, low fabrication cost, and suitable real-time detection. Despite these advantages, they have shown some limitations in the immobilization of biochemicals. The development of alternative materials to overcome these drawbacks has attracted significant attention. Nanocellulose-based materials have revealed valuable features due to their capacity for the immobilization of biomolecules, structural flexibility, and biocompatibility. Bacterial nanocellulose (BNC) has gained a promising role as an alternative to antifouling surfaces. To widen its applicability as a biosensing device, BNC may form part of the supports for the immobilization of specific materials. The possibilities of modification methods and in situ and ex situ functionalization enable new BNC properties. With the new insights into nanoscale studies, we expect that many biosensors currently based on plastic, glass, or paper platforms will rely on renewable platforms, especially BNC ones. Moreover, substrates based on BNC seem to have paved the way for the development of sensing platforms with minimally invasive approaches, such as wearable devices, due to their mechanical flexibility and biocompatibility.

Bacterial Cellulose-Based Polymer Nanocomposites: A Review

Bacterial cellulose (BC) is currently one of the most popular environmentally friendly materials with unique structural and physicochemical properties for obtaining various functional materials for a wide range of applications. In this regard, the literature reporting on bacterial nanocellulose has increased exponentially in the past decade. Currently, extensive investigations aim at promoting the manufacturing of BC-based nanocomposites with other components such as nanoparticles, polymers, and biomolecules, and that will enable to develop of a wide range of materials with advanced and novel functionalities. However, the commercial production of such materials is limited by the high cost and low yield of BC, and the lack of highly efficient industrial production technologies as well. Therefore, the present review aimed at studying the current literature data in the field of highly efficient BC production for the purpose of its further usage to obtain polymer nanocomposites. The review highlights the progress in synthesizing BC-based nanocomposites and their applications in biomedical fields, such as wound healing, drug delivery, tissue engineering. Bacterial nanocellulose-based biosensors and adsorbents were introduced herein.

A Review on the Modification of Cellulose and Its Applications

The latest advancements in cellulose and its derivatives are the subject of this study. We summarize the characteristics, modifications, applications, and properties of cellulose. Here, we discuss new breakthroughs in modified cellulose that allow for enhanced control. In addition to standard approaches, improvements in different techniques employed for cellulose and its derivatives are the subject of this review. The various strategies for synthetic polymers are also discussed. The recent advancements in polymer production allow for more precise control, and make it possible to make functional celluloses with better physical qualities. For sustainability and environmental preservation, the development of cellulose green processing is the most abundant renewable substance in nature. The discovery of cellulose disintegration opens up new possibilities for sustainable techniques. Based on the review of recent scientific literature, we believe that additional chemical units of cellulose solubility should be used. This evaluation will evaluate the sustainability of biomass and processing the greenness for the long term. It appears not only crucial to dissolution, but also to the greenness of any process.

Recent Development and Environmental Applications of Nanocellulose-Based Membranes

Extensive research and development in the production of nanocellulose production, a green, bio-based, and renewable biomaterial has paved the way for the development of advanced functional materials for a multitude of applications. From a membrane technology perspective, the exceptional mechanical strength, high crystallinity, tunable surface chemistry, and anti-fouling behavior of nanocellulose, manifested from its structural and nanodimensional properties are particularly attractive. Thus, an opportunity has emerged to exploit these features to develop nanocellulose-based membranes for environmental applications. This review provides insights into the prospect of nanocellulose as a matrix or as an additive to enhance membrane performance in water filtration, environmental remediation, and the development of pollutant sensors and energy devices, focusing on the most recent progress from 2017 to 2022. A brief overview of the strategies to tailor the nanocellulose surface chemistry for the effective removal of specific pollutants and nanocellulose-based membrane fabrication approaches are also presented. The major challenges and future directions associated with the environmental applications of nanocellulose-based membranes are put into perspective, with primary emphasis on advanced multifunctional membranes.

Nanobioengineered Sensing Technologies Based on Cellulose Matrices for Detection of Small Molecules, Macromolecules, and Cells

Recent advancement has been accomplished in the field of biosensors through the modification of cellulose as a nano-engineered matrix material. To date, various techniques have been reported to develop cellulose-based matrices for fabricating different types of biosensors. Trends of involving cellulosic materials in paper-based multiplexing devices and microfluidic analytical technologies have increased because of their disposable, portable, biodegradable properties and cost-effectiveness. Cellulose also has potential in the development of cytosensors because of its various unique properties including biocompatibility. Such cellulose-based sensing devices are also being commercialized for various biomedical diagnostics in recent years and have also been considered as a method of choice in clinical laboratories and personalized diagnosis. In this paper, we have discussed the engineering aspects of cellulose-based sensors that have been reported where such matrices have been used to develop various analytical modules for the detection of small molecules, metal ions, macromolecules, and cells present in a diverse range of samples. Additionally, the developed cellulose-based biosensors and related analytical devices have been comprehensively described in tables with details of the sensing molecule, readout system, sensor configuration, response time, real sample, and their analytical performances.

Monofunctional pyrenes at carbon nanotube electrodes for direct electron transfer H2O2 reduction with HRP and HRP-bacterial nanocellulose

The non-covalent modification of carbon nanotube electrodes with pyrene derivatives is a versatile approach to enhance the electrical wiring of enzymes for biosensors and biofuel cells. We report here a comparative study of five pyrene derivatives adsorbed at multi-walled carbon nanotube electrodes to shed light on their ability to promote direct electron transfer with horseradish peroxidase (HRP) for H₂O₂ reduction. In all cases, pyrene-modified electrodes enhanced catalytic reduction compared to the unmodified electrodes. The pyrene N-hydroxysuccinimide (NHS) ester derivative provided access to the highest catalytic current of 1.4 mA cm^-2 at 6 mmol L^-1 H₂O₂, high onset potential of 0.61 V vs. Ag/AgCl, insensitivity to parasitic H₂O₂ oxidation, and a large linear dynamic range that benefits from insensitivity to HRP "suicide inactivation" at 4-6 mmol L^-1 H₂O₂. Pyrene-aliphatic carboxylic acid groups offer better sensor sensitivity and higher catalytic currents at ≤ 1 mmol L^-1 H₂O₂ concentrations. The butyric acid and NHS ester derivatives gave high analytical sensitivities of 5.63 A M^-1 cm^-2 and 2.96 A M^-1 cm^-2, respectively, over a wide range (0.25-4 mmol^-1) compared to existing carbon-based HRP biosensor electrodes. A bacterial nanocellulose pyrene-NHS HRP bioelectrode was subsequently elaborated via "one-pot" and "layer-by-layer" strategies. The optimised bioelectrode exhibited slightly weaker voltage output, further enhanced catalytic currents, and a major enhancement in 1-week stability with 67% activity remaining compared to 39% at the equivalent electrode without nanocellulose, thus offering excellent prospects for biosensing and biofuel cell applications.

Gold Nanoparticles Synthesis and Antimicrobial Effect on Fibrous Materials

Depositing nanoparticles in textiles have been a promising strategy to achieve multifunctional materials. Particularly, antimicrobial properties are highly valuable due to the emergence of new pathogens and the spread of existing ones. Several methods have been used to functionalize textile materials with gold nanoparticles (AuNPs). Therefore, this review highlighted the most used methods for AuNPs preparation and the current studies on the topic in order to obtain AuNPs with suitable properties for antimicrobial applications and minimize the environmental concerns in their production. Reporting the detailed information on the functionalization of fabrics, yarns, and fibers with AuNPs by different methods to improve the antimicrobial properties was the central objective. The studies combining AuNPs and textile materials have opened valuable opportunities to develop antimicrobial materials for health and hygiene products, as infection control and barrier material, with improved properties. Future studies are needed to amplify the antimicrobial effect of AuNPs onto textiles and minimize the concerns related to the synthesis.

Solution Blowing Spinning Technology towards Green Development of Urea Sensor Nanofibers Immobilized with Hydrazone Probe

Cellulose has been one of the most widespread materials due to its renewability, excellent mechanical properties, biodegradability, high absorption ability, biocompatibility and cheapness. Novel, simple and green colorimetric fibrous film sensor was developed by immobilization of urease enzyme (U) and tricyanofuran hydrazone (TCFH) molecular probe onto cellulose nanofibers (CNF). Cellulose acetate nanofibers (CANF) were firstly prepared from cellulose acetate using the simple, green and low cost solution blowing spinning technology. The produced CANF was exposed to deacetylation to introduce CNF, which was then treated with a mixture of TCFH and urease enzyme to introduce CNF-TCFH-U nanofibrous biosensor. CNF were reinforced with tricyanofuran hyrazone molecular probe and urease enzyme was encapsulated into calcium alginate biopolymer to establish a biocomposite film. This CNF-TCFH-U naked-eye sensor can be applied as a disposable urea detector. CNF demonstrated a large surface area and was utilized as a carrier for TCFH, which is the spectroscopic probe and urease is a catalyst. The biochromic CNF-TCFH-U nanofibrous biosensor responds to an aqueous medium of urea via a visible color signal changing from off-white to dark pink. The morphology of the generated CNF and CNF-TCFH-U nanofibrous films were characterized by different analytical tools, including energy-dispersive X-ray patterns (EDX), polarizing optical microscope (POM), Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM). SEM images of CNF-TCFH-U nanofibers demonstrated diameters between 800 nm and 2.5 μm forming a nonwoven fabric with a homogeneous distribution of TCFH/urease-containing calcium alginate nanoparticles on the surface of CNF. The morphology of the cross-linked calcium alginate nanoparticles was also explored using transmission electron microscopy (TEM) to indicate an average diameter of 56-66 nm. The photophysical performance of the prepared CNF-TCFH-U was also studied by CIE Lab coloration parameters. The nanofibrous film biosensor displayed a relatively rapid response time (5-10 min) and a limit of detection as low as 200 ppm and as high as 1400 ppm. Tricyanofuran hydrazone is a pH-responsive disperse dye comprising a hydrazone detection group. Determination of urea occurs through a proton transfer from the hydrazone group to the generated ammonia from the reaction of urea with urease.

Surface-Modified Nanocellulose for Application in Biomedical Engineering and Nanomedicine: A Review

Presently, a plenty of concerns related to the environment are due to the overuse of petroleum-based chemicals and products; the synthesis of functional materials, starting from the natural sources, is the current trend in research. The interest for nanocellulose has recently increased in a huge range of fields, from the material science to the biomedical engineering. Nanocellulose gained this leading role because of several reasons: its natural abundance on this planet, the excellent mechanical and optical features, the good biocompatibility and the attractive capability of undergoing surface chemical modifications. Nanocellulose surface tuning techniques are adopted by the high reactivity of the hydroxyl groups available; the chemical modifications are mainly performed to introduce either charged or hydrophobic moieties that include amination, esterification, oxidation, silylation, carboxymethylation, epoxidation, sulfonation, thiol- and azido-functional capability. Despite the several already published papers regarding nanocellulose, the aim of this review involves discussing the surface chemical functional capability of nanocellulose and the subsequent applications in the main areas of nanocellulose research, such as drug delivery, biosensing/bioimaging, tissue regeneration and bioprinting, according to these modifications. The final goal of this review is to provide a novel and unusual overview on this topic that is continuously under expansion for its intrinsic sophisticated properties.

Cellulose-based Biosensor for Bio-molecules Detection in Medical Diagnosis: A Mini-Review

Background::

Biosensors are widely applied for the detection of bio-molecules in blood glucose , cholesterol, and gene. Cellulose as the most dominating natural polymer has attracted more and more interest, especially in the field of medicine such as advanced medical diagnosis. Cellulose could endow biosensors with improved biocompatibility, biodegradability and nontoxicity, which could help in medical diagnosis. This mini-review summarizes the current development of cellulose-based biosensors as well as their applications in medical diagnosis in recent years.

Methods:

After reviewing recent years’ publications we can say that, there are several kinds of cellulose used in biosensors including different cellulose derivatives, bacterial cellulose and nanocellulose. Different types of cellulose-based biosensors, such as membrane, nano-cellulose and others were briefly described in addition to the detection principle. Cellulose-based biosensors were summarized as in the previous papers. The description of various methods used for preparing cellulose-based biosensors was also provided.

Results:

Cellulose and its derivatives with their unique chemical structure proved to be versatile materials providing a good platform for achieving immobilizing bioactive molecules in biosensors. These cellulose-based biosensors possess various desirable properties such as accuracy, sensitivity, convenience, low cost and fast response. Among them, cellulose paper-based biosensors have the advantages of low cost and easy operation. Nano-cellulose has unique properties such as a large aspect ratio, good dispersing ability and high absorption capacity.

Conclusion:

Cellulose displays a promising application in biosensors which could be used to detect different bio-molecules such as glucose, lactate, urea, gene, cell, amino acid, cholesterol, protein and hydroquinone. In future, the attention will be focused on designing miniaturized, multifunctional, intelligent and integrated biosensors. Creation of low cost and environmentally friendly biosensors is also very important.

A Review on Plant Cellulose Nanofibre-Based Aerogels for Biomedical Applications

Cellulose nanomaterials from plant fibre provide various potential applications (i.e., biomedical, automotive, packaging, etc.). The biomedical application of nanocellulose isolated from plant fibre, which is a carbohydrate-based source, is very viable in the 21st century. The essential characteristics of plant fibre-based nanocellulose, which include its molecular, tensile and mechanical properties, as well as its biodegradability potential, have been widely explored for functional materials in the preparation of aerogel. Plant cellulose nano fibre (CNF)-based aerogels are novel functional materials that have attracted remarkable interest. In recent years, CNF aerogel has been extensively used in the biomedical field due to its biocompatibility, renewability and biodegradability. The effective surface area of CNFs influences broad applications in biological and medical studies such as sustainable antibiotic delivery for wound healing, the preparation of scaffolds for tissue cultures, the development of drug delivery systems, biosensing and an antimicrobial film for wound healing. Many researchers have a growing interest in using CNF-based aerogels in the mentioned applications. The application of cellulose-based materials is widely reported in the literature. However, only a few studies discuss the potential of cellulose nanofibre aerogel in detail. The potential applications of CNF aerogel include composites, organic-inorganic hybrids, gels, foams, aerogels/xerogels, coatings and nano-paper, bioactive and wound dressing materials and bioconversion. The potential applications of CNF have rarely been a subject of extensive review. Thus, extensive studies to develop materials with cheaper and better properties, high prospects and effectiveness for many applications are the focus of the present work. The present review focuses on the evolution of aerogels via characterisation studies on the isolation of CNF-based aerogels. The study concludes with a description of the potential and challenges of developing sustainable materials for biomedical applications.

Nanocellulose, a Versatile Green Platform: From Biosources to Materials and Their Applications

With increasing environmental and ecological concerns due to the use of petroleum-based chemicals and products, the synthesis of fine chemicals and functional materials from natural resources is of great public value. Nanocellulose may prove to be one of the most promising green materials of modern times due to its intrinsic properties, renewability, and abundance. In this review, we present nanocellulose-based materials from sourcing, synthesis, and surface modification of nanocellulose, to materials formation and applications. Nanocellulose can be sourced from biomass, plants, or bacteria, relying on fairly simple, scalable, and efficient isolation techniques. Mechanical, chemical, and enzymatic treatments, or a combination of these, can be used to extract nanocellulose from natural sources. The properties of nanocellulose are dependent on the source, the isolation technique, and potential subsequent surface transformations. Nanocellulose surface modification techniques are typically used to introduce either charged or hydrophobic moieties, and include amidation, esterification, etherification, silylation, polymerization, urethanization, sulfonation, and phosphorylation. Nanocellulose has excellent strength, high Young's modulus, biocompatibility, and tunable self-assembly, thixotropic, and photonic properties, which are essential for the applications of this material. Nanocellulose participates in the fabrication of a large range of nanomaterials and nanocomposites, including those based on polymers, metals, metal oxides, and carbon. In particular, nanocellulose complements organic-based materials, where it imparts its mechanical properties to the composite. Nanocellulose is a promising material whenever material strength, flexibility, and/or specific nanostructuration are required. Applications include functional paper, optoelectronics, and antibacterial coatings, packaging, mechanically reinforced polymer composites, tissue scaffolds, drug delivery, biosensors, energy storage, catalysis, environmental remediation, and electrochemically controlled separation. Phosphorylated nanocellulose is a particularly interesting material, spanning a surprising set of applications in various dimensions including bone scaffolds, adsorbents, and flame retardants and as a support for the heterogenization of homogeneous catalysts.

Hydrothermal synthesis of bacterial cellulose-copper oxide nanocomposites and evaluation of their antimicrobial activity

In this work, for the first time bacterial cellulose (BC) hydrogel membranes were used for the fabrication of antimicrobial cellulosic nanocomposites by hydrothermal deposition of Cu derivative nanoparticles (i.e.Cu(0) and CuxOy species). BC-Cu nanocomposites were characterized by FTIR, SEM, AFM, XRD and TGA, to study the effect of hydrothermal processing time on the final physicochemical properties of final products. XRD result show that depending on heating time (3-48h), different CuxOy phases were achieved. SEM and AFM analyses unveil the presence of the Cu(0) and copper CuxOy nanoparticles over BC fibrils while the surface of 3D network became more compact and smother for longer heating times. Furthermore, the increase of heating time placed deleterious effect on the structure of BC network leading to decrease of BC crystallinity as well as of the on-set degradation temperature. Notwithstanding, BC-Cu nanocomposites showed excellent antimicrobial activity against E. coli, S. aureus and Salmonella bacteria suggesting potential applications as bactericidal films.

Production and Status of Bacterial Cellulose in Biomedical Engineering

Bacterial cellulose (BC) is a highly pure and crystalline material generated by aerobic bacteria, which has received significant interest due to its unique physiochemical characteristics in comparison with plant cellulose. BC, alone or in combination with different components (e.g., biopolymers and nanoparticles), can be used for a wide range of applications, such as medical products, electrical instruments, and food ingredients. In recent years, biomedical devices have gained important attention due to the increase in medical engineering products for wound care, regeneration of organs, diagnosis of diseases, and drug transportation. Bacterial cellulose has potential applications across several medical sectors and permits the development of innovative materials. This paper reviews the progress of related research, including overall information about bacterial cellulose, production by microorganisms, mechanisms as well as BC cultivation and its nanocomposites. The latest use of BC in the biomedical field is thoroughly discussed with its applications in both a pure and composite form. This paper concludes the further investigations of BC in the future that are required to make it marketable in vital biomaterials.

Intellectual modifying a bare glassy carbon electrode to fabricate a novel and ultrasensitive electrochemical biosensor: Application to determination of acrylamide in food samples

Acrylamide (AA) is a neurotoxin and carcinogen which is mainly formed in foods containing large quantities of starch processed at high temperatures and its determination is very important to control the quality of foods. In this work, a novel electrochemical biosensor based on hemoglobin-dimethyldioctadecylammonium bromide (HG-DDAB)/platinum-gold-palladium three metallic alloy nanoparticles (PtAuPd NPs)/chitosan-1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (Ch-IL)/multiwalled carbon nanotubes-IL (MWCNTs-IL)/glassy carbon electrode (GCE) is proposed for ultrasensitive determination of AA in food samples. Development of the biosensor is based on forming an adduct by the reaction of AA with α-NH₂ group of N-terminal valine of HG which decreases the peak current of HG-Fe⁺³ reduction. The modifications were characterized by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), energy dispersive X-ray spectroscopic (EDS) and scanning electron microscopy (SEM). Under optimized conditions, the biosensor detected AA by square wave voltammetry (SWV) in two linear concentration ranges of 0.03-39.0nM and 39.0-150.0nM with a limit of detection (LOD) of 0.01nM. The biosensor was able to selective detection of AA even in the presence of high concentrations of common interferents which confirmed that the biosensor is highly selective. Also, the results obtained from further studies confirmed that the proposed biosensor has a short response time (less than 8s), good sensitivity, long term stability, repeatability, and reproducibility. Finally, the proposed biosensor was successfully applied to determine AA in potato chips and its results were comparable to those obtained by gas chromatography-mass spectrometry (GC-MS) as reference method.

Cellulose-gold nanoparticle hybrid materials

Cellulose and gold nanoparticles have exciting characteristics and new combinations of both materials may lead to promising functional nanocomposites with unique properties. We have reviewed current research on cellulose-gold nanoparticle composite materials, and we present an overview of the preparation methods of cellulose-gold composite materials and discuss their applications. We start with the nanocomposite fabrication methods, covering in situ gold reduction, blending, and dip-coating methods to prepare gold-cellulose nanocomposite hybrids. We then move on to a discussion of the ensuing properties where the combination of gold nanoparticles with cellulose results in functional materials with specific catalytic, antimicrobial, sensing, antioxidant and Surface Enhanced Raman Scattering (SERS) performance. Studies have also been carried out on orientationally ordered composite materials and on the chiral nematic phase behaviour of these nanocomposites. To exert even more control over the structure formation and the resultant properties of these functional materials, fundamental studies on the physico-chemical interactions of cellulose and gold are necessary to understand better the driving forces and limitations towards structuring of gold-cellulose hybrid materials.

Catalase-Based Modified Graphite Electrode for Hydrogen Peroxide Detection in Different Beverages

A catalase-based (NAF/MWCNTs) nanocomposite film modified glassy carbon electrode for hydrogen peroxide (H2O2) detection was developed. The developed biosensor was characterized in terms of its bioelectrochemical properties. Cyclic voltammetry (CV) technique was employed to study the redox features of the enzyme in the absence and in the presence of nanomaterials dispersed in Nafion® polymeric solution. The electron transfer coefficient, α, and the electron transfer rate constant, ks , were found to be 0.42 and 1.71 s-1, at pH 7.0, respectively. Subsequently, the same modification steps were applied to mesoporous graphite screen-printed electrodes. Also, these electrodes were characterized in terms of their main electrochemical and kinetic parameters. The biosensor performances improved considerably after modification with nanomaterials. Moreover, the association of Nafion with carbon nanotubes retained the biological activity of the redox protein. The enzyme electrode response was linear in the range 2.5-1150 μmol L-1, with LOD of 0.83 μmol L-1. From the experimental data, we can assess the possibility of using the modified biosensor as a useful tool for H2O2 determination in packaged beverages.

Do bacterial cellulose membranes have potential in drug-delivery systems?

INTRODUCTION

Bacterial cellulose (BC) is an extremely pure form of cellulose, which, due to its unique properties, such as high purity, water-holding capacity, three-dimensional nanofibrilar network, mechanical strength, biodegradability and biocompatibility, shows a high potential as nanomaterial in a wide range of high-tech domains including biomedical applications, and most notably in controlled drug-delivery systems.

AREAS COVERED

This appraisal is intended to cover the major characteristics of BC, followed by the key aspects of BC production both in static and agitated conditions, and a glance of the major applications of BC, giving some emphasis to biomedical applications. Finally, a detailed discussion of the different applications of BC in controlled drug-delivery systems will be put forward, with focus on topical and oral drug-delivery systems, using either native BC or composite materials thereof.

EXPERT OPINION

The limited number of studies carried out so far demonstrated that BC, or materials prepared from it, are interesting materials for drug-delivery systems. There is, however, a large field of systematic research ahead to develop new and more selectively responsive materials and eventually to conjugate them with other biomedical applications of BC under development.

Functionalized bacterial cellulose derivatives and nanocomposites

Bacterial cellulose (BC) is a fascinating and renewable natural nanomaterial characterized by favorable properties such as remarkable mechanical properties, porosity, water absorbency, moldability, biodegradability and excellent biological affinity. Intensive research and exploration in the past few decades on BC nanomaterials mainly focused on their biosynthetic process to achieve the low-cost preparation and application in medical, food, advanced acoustic diaphragms, and other fields. These investigations have led to the emergence of more diverse potential applications exploiting the functionality of BC nanomaterials. This review gives a summary of construction strategies including biosynthetic modification, chemical modification, and different in situ and ex situ patterns of functionalization for the preparation of advanced BC-based functional nanomaterials. The major studies being directed toward elaborate designs of highly functionalized material systems for many-faceted prospective applications. Simple biosynthetic or chemical modification on BC surface can improve its compatibility with different matrix and expand its utilization in nano-related applications. Moreover, based on the construction strategies of functional nanomaterial system, different guest substrates including small molecules, inorganic nanoparticles or nanowires, and polymers can be incorporated onto the surfaces of BC nanofibers to prepare various functional nanocomposites with outstanding properties, or significantly improved physicochemical, catalytic, optoelectronic, as well as magnetic properties. We focus on the preparation methods, formation mechanisms, and unique performances of the different BC derivatives or BC-based nanocomposites. The special applications of the advanced BC-based functional nanomaterials, such as sensors, photocatalytic nanomaterials, optoelectronic devices, and magnetically responsive membranes are also critically and comprehensively reviewed.