Biomechanical behaviour of PEDOT:PSS-based hydrogels as an electrode for stent integrated enzyme biofuel cells

Fueling the Future: The Emergence of Self-Powered Enzymatic Biofuel Cell Biosensors

Self-powered biosensors are innovative devices that can detect and analyze biological or chemical substances without the need for an external power source. These biosensors can convert energy from the surrounding environment or the analyte itself into electrical signals for sensing and data transmission. The self-powered nature of these biosensors offers several advantages, such as portability, autonomy, and reduced waste generation from disposable batteries. They find applications in various fields, including healthcare, environmental monitoring, food safety, and wearable devices. While self-powered biosensors are a promising technology, there are still challenges to address, such as improving energy efficiency, sensitivity, and stability to make them more practical and widely adopted. This review article focuses on exploring the evolving trends in self-powered biosensor design, outlining potential advantages and limitations. With a focal point on enzymatic biofuel cell power generation, this article describes various sensing mechanisms that employ the analyte as substrate or fuel for the biocatalyst's ability to generate current. Technical aspects of biofuel cells are also examined. Research and development in the field of self-powered biosensors is ongoing, and this review describes promising areas for further exploration within the field, identifying underexplored areas that could benefit from further investigation.

Iodonium-based pro-adhesive layers for robust adhesion of PEDOT:PSS to surfaces

Electrochemical grafting of organic molecules to metal surfaces has been well-known as an efficient tool enabling tailored modification of surface at the nanoscale. Among many compounds with the ability to undergo the process of electrografting, iodonium salts belong to less frequently used, especially when compared with the most popular diazonium salts. Meanwhile, due to their increased stability, iodonium salts may be used in situations where the use of diazonium salts is constrained. The aim of this study was to examine the effect of the electrochemical reduction of iodonium salts on the physicochemical properties of Pt electrodes, and the possibility to form pro-adhesive layers facilitating further functionalization purposes. Consequently, we have selected four commercially available iodonium salts (diphenyliodonium chloride, bis(4-tertbutylphenyl)iodonium hexafluorophosphate, (4-nitrophenyl)(2,4,6-trimethylphenyl)iodonium triflate, bis(4-methylphenyl)iodonium hexafluorophosphate), and attached them to the surface of Pt electrodes by means of an electrochemical reduction process. As-formed layers were then extensively characterized in terms of wettability, roughness and charge transfer properties, and used as pro-adhesive coatings prior to the deposition of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate), PEDOT:PSS. Due to the increase in hydrophilicity and roughness, modified electrodes increased the stability of PEDOT:PSS coating while maintaining its high capacitance.

Fabrication of Sodium Trimetaphosphate-Based PEDOT:PSS Conductive Hydrogels

Conductive hydrogels are highly attractive for biomedical applications due to their ability to mimic the electrophysiological environment of biological tissues. Although conducting polymer polythiophene-poly-(3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonate (PSS) alone exhibit high conductivity, the addition of other chemical compositions could further improve the electrical and mechanical properties of PEDOT:PSS, providing a more promising interface with biological tissues. Here we study the effects of incorporating crosslinking additives, such as glycerol and sodium trimetaphosphate (STMP), in developing interpenetrating PEDOT:PSS-based conductive hydrogels. The addition of glycerol at a low concentration maintained the PEDOT:PSS conductivity with enhanced wettability but decreased the mechanical stiffness. Increasing the concentration of STMP allowed sufficient physical crosslinking with PEDOT:PSS, resulting in improved hydrogel conductivity, wettability, and rheological properties without glycerol. The STMP-based PEDOT:PSS conductive hydrogels also exhibited shear-thinning behaviors, which are potentially favorable for extrusion-based 3D bioprinting applications. We demonstrate an interpenetrating conducting polymer hydrogel with tunable electrical and mechanical properties for cellular interactions and future tissue engineering applications.

Biodegradable, Biocompatible, and Implantable Multifunctional Sensing Platform for Cardiac Monitoring

Cardiac monitoring after heart surgeries is crucial for health maintenance and detecting postoperative complications early. However, current methods like rigid implants have limitations, as they require performing second complex surgeries for removal, increasing infection and inflammation risks, thus prompting research for improved sensing monitoring technologies. Herein, we introduce a nanosensor platform that is biodegradable, biocompatible, and integrated with multifunctions, suitable for use as implants for cardiac monitoring. The device has two electrochemical biosensors for sensing lactic acid and pH as well as a pressure sensor and a chemiresistor array for detecting volatile organic compounds. Its biocompatibility with myocytes has been tested in vitro, and its biodegradability and sensing function have been proven with ex vivo experiments using a three-dimensional (3D)-printed heart model and 3D-printed cardiac tissue patches. Moreover, an artificial intelligence-based predictive model was designed to fuse sensor data for more precise health assessment, making it a suitable candidate for clinical use. This sensing platform promises impactful applications in the realm of cardiac patient care, laying the foundation for advanced life-saving developments.

Conductive Polymers and Their Nanocomposites: Application Features in Biosensors and Biofuel Cells

Conductive polymers and their composites are excellent materials for coupling biological materials and electrodes in bioelectrochemical systems. It is assumed that their relevance and introduction to the field of bioelectrochemical devices will only grow due to their tunable conductivity, easy modification, and biocompatibility. This review analyzes the main trends and trends in the development of the methodology for the application of conductive polymers and their use in biosensors and biofuel elements, as well as describes their future prospects. Approaches to the synthesis of such materials and the peculiarities of obtaining their nanocomposites are presented. Special emphasis is placed on the features of the interfaces of such materials with biological objects.

Conductive polymers and composites-based systems: An incipient stride in drug delivery and therapeutics realm

Novel therapies and drug delivery systems (DDS) emphasis on localized, personalized, triggered, and regulated drug administration have heavily implicated electrically responsive DDS. An ideal DDS must deliver drugs to the target region at therapeutically effective concentrations to elicit a pharmacological response, resulting in better prophylaxis of the disease and the treatment. Biodegradable polymers are frequently employed for in-vivo long-term release; however, dose dumping can be anticipated. As a result, current DDSs can be tagged as dubbed "Smart Biomaterials" since they only focus on an on-demand cargo release in response to a trigger or stimulation. These organic materials have been recognized for their metal-like conductivity, as well as their mechanical stability and ease of production. These biomaterials can be programmed to respond to both internal and external stimuli. External pulsed triggers are required for extrinsic stimuli-responsive materials, whereas intrinsic stimuli-responsive materials rely on localized changes in the tissue environment. Furthermore, these materials have the ability to deliver active pharmaceutical agents at a varied concentration levels and across a broad spectrum of action. Drug delivery, biomedical implant technology, biosensor technology, and tissue engineering can be listed as a few prominent applications that have sparked immense interest for conductive polymers-based research and advancements in academia as well as in industry. This review comprehensively covers a cutting-edge collection of electrically conductive polymers and composites, and provide detailed insights of recent trends and advancements allied to conductive polymers for their potential applicability in an array of diverse meadows primarily focusing on drug delivery, biosensing and therapeutics. Furthermore, progressions in their synthesis, structural and functional properties have been presented in conjunction with futuristic directions for the smooth clinical translations.