Minimizing the negative charge of Alginate facilitates the delivery of negatively charged molecules inside cells

Next-Generation Chemiresistive Wearable Breath Sensors for Non-Invasive Healthcare Monitoring: Advances in Composite and Hybrid Materials

Recently wearable breath sensors have received significant attention in personalized healthcare systems by offering new methods for remote, non-invasive, and continuous monitoring of various health indicators from breath samples without disrupting daily routines. The rising demand for rapid, personalized diagnostics has sparked concerns over electronic waste from short-lived silicon-based devices. To address this issue, the development of flexible and wearable sensors for breath sensing applications is a promising approach. Research highlights the development of different flexible, wearable sensors operating with different operating principles, such as chemiresistive sensors to detect specific target analytes due to their simple design, high sensitivity, selectivity, and reliability. Further, focusing on the non-invasive detection of biomarkers through exhaled breath, chemiresistive wearable sensors offer a comprehensive and environmentally friendly solution. This article presents a comprehensive discussion of the recent advancement in chemiresistive wearable breath sensors for the non-invasive detection of breath biomarkers. The article further emphasizes the intricate development and functioning of the sensor, including the selection criteria for both the flexible substrate and advanced functional materials, including their sensing mechanisms. The review then explores the potential applications of wearable gas sensing systems with specific disease detection, with modern challenges associated with non-invasive breath sensors.

Development of a mucoadhesive drug delivery system and its interaction with gastric cells

Drugs that are designed for local treatment of gastric diseases require increased gastric residence time for prolonged action and increased efficacy. In this study, we report a mucoadhesive drug delivery system that was developed to fulfill these requirements. Alginate nanoparticles were synthesized by water-in-oil emulsification followed by external gelation and then coated with the mucoadhesive polymer Eudragit RS100. The formulated nanoparticles had a mean size of 219 nm and positive charge. A peptide, as a model drug, was loaded onto the nanoparticles with an encapsulation efficiency of 58%. The release of the model drug from the delivery system was pH-independent and lasted for 7 days. The periodic acid-Schiff stain assay indicated 69% mucin interaction for the nanoparticles, which were also capable of diffusion through artificial mucus. The nanoparticles were not toxic to gastric epithelial cells and can be internalized by the cells within 4 h. The adsorption of nanoparticles onto mucus-secreting gastric cells was found to be correlated with cell number. The delivery system developed in this study is intended to be loaded with active therapeutic agents and has the potential to be used as an alternative drug delivery strategy for the treatment of gastric related diseases.

Room temperature operated flexible MWCNTs/Nb2O5 hybrid breath sensor for the non-invasive detection of an exhaled diabetes biomarker

Advancements in diabetes management increasingly rely on non-invasive monitoring of biomarkers present in exhaled breath. This study introduces a novel room temperature operated flexible acetone sensing platform, leveraging a hybrid material composed of multi-walled carbon nanotubes (MWCNTs) and niobium oxide (Nb2O5). The platform demonstrates sensitivity and selectivity towards acetone, a prominent biomarker of diabetes, offering promise for real-time health monitoring applications. The sensor exhibited a characteristic feature of fast response (25 s) and recovery times (46 s) at 50 ppm, good selectivity, and stability with a detection limit of 330 ppb. Additionally, the sensor's characteristic features were collected, and four different machine learning (ML) algorithms were applied to visualize and classify the gases with good quantification. Out of all algorithms, the random forest (RF) algorithm demonstrates the best performance. Furthermore, regression modelling was also used to quantitatively predict the gas concentration. In addition, the sensor was shown to distinguish between signals from simulated diabetic and healthy breath samples. These sensing performances indicate that the breath sensor has practical applications that could potentially provide a non-invasive monitoring method for diabetic patients.

Nanomaterials and methods for cancer therapy: 2D materials, biomolecules, and molecular dynamics simulations

This review explores the potential of biomolecule-based nanomaterials, i.e., protein, peptide, nucleic acid, and polysaccharide-based nanomaterials, in cancer nanomedicine. It highlights the wide range of design possibilities for creating multifunctional nanomedicines using these biomolecule-based nanomaterials. This review also analyzes the primary obstacles in cancer nanomedicine that can be resolved through the usage of nanomaterials based on biomolecules. It also examines the unique in vivo characteristics, programmability, and biological functionalities of these biomolecule-based nanomaterials. This summary outlines the most recent advancements in the development of two-dimensional semiconductor-based nanomaterials for cancer theranostic purposes. It focuses on the latest developments in molecular simulations and modelling to provide a clear understanding of important uses, techniques, and concepts of nanomaterials in drug delivery and synthesis processes. Finally, the review addresses the challenges in molecular simulations, and generating, analyzing, and developing biomolecule-based and two-dimensional semiconductor-based nanomaterials, and highlights the barriers that must be overcome to facilitate their application in clinical settings.

Comparison of cation and anion-mediated resolution enhancement of bioprinted hydrogels for membranous tissue fabrication

Fabrication of engineered thin membranous tissues (TMTs) presents a significant challenge to researchers, as these structures are small in scale, but present complex anatomies containing multiple stratified cell layers. While numerous methodologies exist to fabricate such tissues, many are limited by poor mechanical properties, need for post-fabrication, or lack of cytocompatibility. Extrusion bioprinting can address these issues, but lacks the resolution necessary to generate biomimetic, microscale TMT structures. Therefore, our goal was to develop a strategy that enhances bioprinting resolution below its traditional limit of 150 μm and delivers a viable cell population. We have generated a system to effectively shrink printed gels via electrostatic interactions between anionic and cationic polymers. Base hydrogels are composed of gelatin methacrylate type A (cationic), or B (anionic) treated with anionic alginate, and cationic poly-L-lysine, respectively. Through a complex coacervation-like mechanism, the charges attract, causing compaction of the base GelMA network, leading to reduced sample dimensions. In this work, we evaluate the role of both base hydrogel and shrinking polymer charge on effective print resolution and cell viability. The alginate anion-mediated system demonstrated the ability to reach bioprinting resolutions of 70 μm, while maintaining a viable cell population. To our knowledge, this is the first study that has produced such significant enhancement in extrusion bioprinting capabilities, while also remaining cytocompatible.

Biofilm matrix: a multifaceted layer of biomolecules and a defensive barrier against antimicrobials

Bacterial cells often exist in the form of sessile aggregates known as biofilms, which are polymicrobial in nature and can produce slimy Extracellular Polymeric Substances (EPS). EPS is often referred to as a biofilm matrix and is a heterogeneous mixture of various biomolecules such as polysaccharides, proteins, and extracellular DNA/RNA (eDNA/RNA). In addition, bacteriophage (phage) was also found to be an integral component of the matrix and can serve as a protective barrier. In recent years, the roles of proteins, polysaccharides, and phages in the virulence of biofilms have been well studied. However, a mechanistic understanding of the release of such biomolecules and their interactions with antimicrobials requires a thorough review. Therefore, this article critically reviews the various mechanisms of release of matrix polymers. In addition, this article also provides a contemporary understanding of interactions between various biomolecules to protect biofilms against antimicrobials. In summary, this article will provide a thorough understanding of the functions of various biofilm matrix molecules.

Algae polysaccharide-induced transport transformation of nanoplastics in seawater-saturated porous media

This study examined the distinct effects of algae polysaccharides (AP), namely sodium alginate (SA), fucoidan (FU), and laminarin (LA), on the aggregation of nanoplastics (NP) in seawater, as well as their subsequent transport in seawater-saturated sea sand. The pristine 50 nm NP tended to form large aggregates, with an average size of approximately 934.5 ± 11 nm. Recovery of NP from the effluent (Meff) was low, at only 18.2 %, and a ripening effect was observed in the breakthrough curve (BTC). Upon the addition of SA, which contains carboxyl groups, the zeta (ζ)-potential of the NP increased by 2.8 mV. This modest enhancement of electrostatic interaction with NP colloids led to a reduction in the aggregation size of NP to 598.0 ± 27 nm and effectively mitigated the ripening effect observed in the BTC. Furthermore, SA's adherence to the sand surface and the resulting increase in electrostatic repulsion, caused a rise in Meff to 27.5 %. In contrast, the introduction of FU, which contains sulfate ester groups, resulted in a surge in ζ-potential of the NP to -27.7 ± 0.76 mV. The intensified electrostatic repulsion between NP and between NP and sand greatly increased Meff to 45.6 %. Unlike the effects of SA and FU, the addition of LA, a neutral compound, caused a near disappearance of ζ-potential of NP (-3.25 ± 0.68 mV). This change enhanced the steric hindrance effect, resulting in complete stabilization of particles and a blocking effect in the BTC of NP. Quantum chemical simulations supported the significant changes in the electrostatic potential of NP colloids induced by SA, FU and LA. In summary, the presence of AP can induce variability in the mobility of NP in seawater-saturated porous media, depending on the nature of the weak, strong, or non-electrostatic interactions between colloids, which are influenced by the structure and functionalization of the polysaccharides themselves. These findings provide valuable insights into the complex and variable behavior of NP transport in the marine environment.

Bio-Inspired Electrodes with Rational Spatiotemporal Management for Lithium-Ion Batteries

Lithium-ion batteries (LIBs) are currently the predominant energy storage power source. However, the urgent issues of enhancing electrochemical performance, prolonging lifetime, preventing thermal runaway-caused fires, and intelligent application are obstacles to their applications. Herein, bio-inspired electrodes owning spatiotemporal management of self-healing, fast ion transport, fire-extinguishing, thermoresponsive switching, recycling, and flexibility are overviewed comprehensively, showing great promising potentials in practical application due to the significantly enhanced durability and thermal safety of LIBs. Taking advantage of the self-healing core-shell structures, binders, capsules, or liquid metal alloys, these electrodes can maintain the mechanical integrity during the lithiation-delithiation cycling. After the incorporation of fire-extinguishing binders, current collectors, or capsules, flame retardants can be released spatiotemporally during thermal runaway to ensure safety. Thermoresponsive switching electrodes are also constructed though adding thermally responsive components, which can rapidly switch LIB off under abnormal conditions and resume their functions quickly when normal operating conditions return. Finally, the challenges of bio-inspired electrode designs are presented to optimize the spatiotemporal management of LIBs. It is anticipated that the proposed electrodes with spatiotemporal management will not only promote industrial application, but also strengthen the fundamental research of bionics in energy storage.

Fabrication of a poly(N-isopropylacrylamide)-grafted alginate composite aerogel for efficient treatment of emulsified oily wastewater

The treatment of emulsion wastewater poses significant challenges. In this study, a novel porous material, namely esterified bagasse/poly(N, N-dimethylacrylamide)/sodium alginate (SBS/PDMAA/Alg) aerogel, was developed for efficient demulsification and oil recovery. By grafting a poly(N-isopropylacrylamide) (PNIPAM) brush onto the SBS/PDMAA/Alg skeleton through free radical polymerization, the resulting aerogel exhibits both surface charge and a molecular brush structure. The aerogel demonstrates remarkable demulsification efficiency for cationic surfactant-stabilized emulsions at various concentrations, achieving a demulsification efficiency of 95.6% even at an oil content of 100 g L-1. Furthermore, the molecular brush structure extends the application range of the aerogel, enabling a demulsification efficiency of 98.3% for anionic and non-ionic surfactant-stabilized emulsions. The interpenetrating polymer network (IPN) structure formed by SBS, PDMAA, and alginate enhances the mechanical stability of the aerogel, enabling a demulsification efficiency of 91.3% even after 20 repeated cycles. The demulsification ability of the composite aerogel is attributed to its surface charge, high interfacial activity, and unique brush-like structure. A demulsification mechanism based on the synergistic effect of surface charge and molecular brush is proposed to elucidate the efficient demulsification process.

Overcoming colloidal nanoparticle aggregation in biological milieu for cancer therapeutic delivery: Perspectives of materials and particle design

Nanoparticles as cancer therapeutic carrier fail in clinical translation due to complex biological environments in vivo consisting of electrolytes and proteins which render nanoparticle aggregation and unable to reach action site. This review identifies the desirable characteristics of nanoparticles and their constituent materials that prevent aggregation from site of administration (oral, lung, injection) to target site. Oral nanoparticles should ideally be 75-100 nm whereas the size of pulmonary nanoparticles minimally affects their aggregation. Nanoparticles generally should carry excess negative surface charges particularly in fasting state and exert steric hindrance through surface decoration with citrate, anionic surfactants and large polymeric chains (polyethylene glycol and polyvinylpyrrolidone) to prevent aggregation. Anionic as well as cationic nanoparticles are both predisposed to protein corona formation as a function of biological protein isoelectric points. Their nanoparticulate surface composition as such should confer hydrophilicity or steric hindrance to evade protein corona formation or its formation should translate into steric hindrance or surface negative charges to prevent further aggregation. Unexpectedly, smaller and cationic nanoparticles are less prone to aggregation at cancer cell interface favoring endocytosis whereas aggregation is essential to enable nanoparticles retention and subsequent cancer cell uptake in tumor microenvironment. Present studies are largely conducted in vitro with simplified simulated biological media. Future aggregation assessment of nanoparticles in biological fluids that mimic that of patients is imperative to address conflicting materials and designs required as a function of body sites in order to realize the future clinical benefits.

Effects of mechanical properties of carbon-based nanocomposites on scaffolds for tissue engineering applications: a comprehensive review

Mechanical properties, such as elasticity modulus, tensile strength, elongation, hardness, density, creep, toughness, brittleness, durability, stiffness, creep rupture, corrosion and wear, a low coefficient of thermal expansion, and fatigue limit, are some of the most important features of a biomaterial in tissue engineering applications. Furthermore, the scaffolds used in tissue engineering must exhibit mechanical and biological behaviour close to the target tissue. Thus, a variety of materials has been studied for enhancing the mechanical performance of composites. Carbon-based nanostructures, such as graphene oxide (GO), reduced graphene oxide (rGO), carbon nanotubes (CNTs), fibrous carbon nanostructures, and nanodiamonds (NDs), have shown great potential for this purpose. This is owing to their biocompatibility, high chemical and physical stability, ease of functionalization, and numerous surface functional groups with the capability to form covalent bonds and electrostatic interactions with other components in the composite, thus significantly enhancing their mechanical properties. Considering the outstanding capabilities of carbon nanostructures in enhancing the mechanical properties of biocomposites and increasing their applicability in tissue engineering and the lack of comprehensive studies on their biosafety and role in increasing the mechanical behaviour of scaffolds, a comprehensive review on carbon nanostructures is provided in this study.

A simple approach to develop a paper-based biosensor for real-time uric acid detection

The current work reports the development of an inexpensive real-time sensing module for uric acid detection on a simple, disposable paper substrate. Detection is based on a capacitive measurement system using functional ZnO hexagonal rods on pulse-electrodeposited Cu interdigitated electrodes (IDEs) over hydrophobic A4 paper. Both the prepared hydrophobic A4 paper and ZnO hexagonal rods are well characterized using field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), UV-visible spectrophotometry (UV-Vis), Raman spectroscopy, and contact angle measurement. Arduino IDE software is used to configure the Arduino Mega board to evaluate the change in the capacitance value and to display the corresponding uric acid concentration on a liquid crystal display (LCD) screen. The experimental result shows the linear relationship in the range of 0.1 mM-1 mM concentration of uric acid with a high sensitivity of 9.00 μF mM^-1 cm^-2 at 0.1 mM. The results indicate that the developed capacitance measurement unit can be employed for the early screening of uric acid in real samples for clinical applications. The reported proof-of-concept has huge potential towards the development of a disposable and inexpensive biosensor platform.

Facile fabrication of a novel self-healing and flame-retardant hydrogel/MXene coating for wood

To improve flame retardancy of wood, a novel high-water-retention and self-healing polyvinyl alcohol/phytic acid/MXene hydrogel coating was developed through facile one-pot heating and freeze-thaw cycle methods, and then painted on wood surface. The coating exhibit excellent self-healing property and significantly enhanced water-retention property (water content ≥ 90 wt%), due to the increased hydrogen bonds within the coating system with the presence of MXene nanosheets. Compared to pristine wood, the flame retardancy of coated wood is greatly improved, such as passed V0 rating in UL-94 test, increasing time to ignition (TTI, from 32 to 69 s), and decreased heat release rate and total heat release by 41.6% and 36.14%. The cooling effect and large thermal capacity of high-water-retention hydrogel, and physical barrier effects for flammable gas products, heat and oxygen by MXene nanosheets and the compact char layer formed during combustion play key roles in the flame retardancy enhancements of the wood. High thermal stability of MXene nanosheets is another beneficial factor. The detailed flame-retardant and self-healing mechanisms were proposed.

Sodium Alginate-Doping Cationic Nanoparticle As Dual Gene Delivery System for Genetically Bimodal Therapy

Photodynamic therapy occupies an important position in cancer therapy because of its minimal invasiveness and high spatiotemporal precision, and photodynamic/gene combined therapy is a promising strategy for additive therapeutic effects. However, the asynchronism and heterogeneity between traditional chemical photosensitizers and nucleic acid would restrict the feasibility of this strategy. KillerRed protein, as an endogenous photosensitizer, could be directly expressed and take effect in situ by transfecting KillerRed reporter genes into cells. Herein, a simple and easily prepared sodium alginate (SA)-doping cationic nanoparticle SA@GP/DNA was developed for dual gene delivery. The nanoparticles could be formed through electrostatic interaction among sodium alginate, polycation, and plasmid DNA. The title complex SA@GP/DNA showed good biocompatibility and gene transfection efficiency. Mechanism studies revealed that SA doping could facilitate the cellular uptake and DNA release. Furthermore, SA@GP/DNA was applied to the codelivery of p53 and KillerRed reporter genes for the synergistic effect combining p53-mediated apoptosis therapy and KillerRed-mediated photodynamic therapy. The ROS generation, tumor cell growth inhibition, and apoptosis assays proved that the dual-gene transfection could mediate the better effect compared with single therapy. This rationally designed dual gene codelivery nanoparticle provides an effective and promising platform for genetically bimodal therapy.

Electroactive calcium-alginate/polycaprolactone/reduced graphene oxide nanohybrid hydrogels for skeletal muscle tissue engineering

Graphene derivatives such as reduced graphene oxide (rGO) are used as components of novel biomaterials for their unique electrical properties. Electrical conductivity is a crucial factor for muscle cells, which are electrically active. This study reports the development of a new type of semi-interpenetrated polymer network based on two biodegradable FDA-approved biomaterials, sodium alginate (SA) and polycaprolactone (PCL), with Ca²⁺ ions as SA crosslinker. Several drawbacks such as the low cell adhesion of SA and weak structural stability can be improved with the incorporation of PCL. Furthermore, this study demonstrates how this semi-IPN can be engineered with rGO nanosheets (0.5% and 2% wt/wt rGO nanosheets) to produce electroactive nanohybrid composite biomaterials. The study focuses on the microstructure and the enhancement of physical and biological properties of these advanced materials, including water sorption, surface wettability, thermal behavior and thermal degradation, mechanical properties, electrical conductivity, cell adhesion and myogenic differentiation. The results suggest the formation of a complex nano-network with different interactions between the components: bonds between SA chains induced by Ca²⁺ ions (egg-box model), links between rGO nanosheets and SA chains as well as between rGO nanosheets themselves through Ca²⁺ ions, and strong hydrogen bonding between rGO nanosheets and SA chains. The incorporation of rGO significantly increases the electrical conductivity of the nanohybrid hydrogels, with values in the range of muscle tissue. In vitro cultures with C2C12 murine myoblasts revealed that the conductive nanohybrid hydrogels are not cytotoxic and can greatly enhance myoblast adhesion and myogenic differentiation. These results indicate that these novel electroactive nanohybrid hydrogels have great potential for biomedical applications related to the regeneration of electroactive tissues, particularly in skeletal muscle tissue engineering.