Institute of Fundamental Technological Research

Hydrogels with multifunctional properties activated at specific times have gained significant attention in the biomedical field. As bacterial infections can cause severe complications that negatively impact wound repair, herein, we present the development of a stimuli-responsive, injectable, and in situ-forming hydrogel with antibacterial, self-healing, and drug-delivery properties. In this study, we prepared a Pluronic F-127 (PF127) and sodium alginate (SA)-based hydrogel that can be targeted to a specific tissue via injection. The PF127/SA hydrogel was incorporated with polymeric short-filaments (SFs) containing an anti-inflammatory drug – ketoprofen, and stimuli-responsive polydopamine (PDA) particles. The hydrogel, after injection, could be in situ gelated at the body temperature, showing great in vitro stability and self-healing ability after 4 h of incubation. The SFs and PDA improved the hydrogel injectability and compressive strength. The introduction of PDA significantly accelerated the KET release under near-infrared light exposure and extended its release validity period. The excellent composites’ photo-thermal performance led to antibacterial activity against representative Gram-positive and Gram-negative bacteria, resulting in 99.9% E. coli and S. aureus eradication after 10 min of NIR light irradiation. In vitro, fibroblast L929 cell studies confirmed the materials’ biocompatibility and paved the way toward further in vivo and clinical application of the system for chronic wound treatments.

The shortage of face masks and the lack of antipathogenic functions has been significant since the recent pandemic's inception. Moreover, the disposal of an enormous number of contaminated face masks not only carries a significant environmental impact but also escalates the risk of cross-contamination. This study proposes a strategy to upgrade available surgical masks into antibacterial masks with enhanced particle and bacterial filtration. Plasmonic nanoparticles can provide photodynamic and photothermal functionalities for surgical masks. For this purpose, gold nanorods act as on-demand agents to eliminate pathogens on the surface of the masks upon near-infrared light irradiation. Additionally, the modified masks are furnished with polymer electrospun nanofibrous layers. These electrospun layers can enhance the particle and bacterial filtration efficiency, not at the cost of the pressure drop of the mask. Consequently, fabricating these prototype masks could be a practical approach to upgrading the available masks to alleviate the environmental toll of disposable face masks.

Hierarchical nanostructures fabricate by electrospinning in combination with light-responsive agents offer promising scenarios for developing novel activable antibacterial interfaces. This study introduces an innovative antibacterial face mask developed from poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanofibers integrated with indocyanine green (ICG), targeting the urgent need for effective antimicrobial protection for community health workers. The research focuses on fabricating and characterizing this nanofibrous material, evaluating the mask's mechanical and chemical properties, investigating its particle filtration, and assessing antibacterial efficacy under photothermal conditions for reactive oxygen species (ROS) generation. The PHBV/ICG nanofibers are produced using an electrospinning process, and the nanofibrous construct's morphology, structure, and photothermal response are investigated. The antibacterial efficacy of the nanofibers is tested, and substantial bacterial inactivation under both near-infrared (NIR) and solar irradiation is demonstrated due to the photothermal response of the nanofibers. The material's photothermal response is further analyzed under cyclic irradiation to simulate real-world conditions, confirming its durability and consistency. This study highlights the synergistic impact of PHBV and ICG in enhancing antibacterial activity, presenting a biocompatible and environmentally friendly solution. These findings offer a promising path for developing innovative face masks that contribute significantly to the field of antibacterial materials and solve critical public health challenges.

In neuroscience, the acquisition of neural signals from the brain cortex is crucial to analyze brain processes, detect neurological disorders, and offer therapeutic brain–computer interfaces. The design of neural interfaces conformable to the brain tissue is one of today’s major challenges since the insufficient biocompatibility of those systems provokes a fibrotic encapsulation response, leading to an inaccurate signal recording and tissue damage precluding long-term/permanent implants. The design and production of a novel soft neural biointerface made of polyacrylamide hydrogels loaded with plasmonic silver nanocubes are reported herein. Hydrogels are surrounded by a silicon-based template as a supporting element for guaranteeing an intimate neural-hydrogel contact while making possible stable recordings from specific sites in the brain cortex. The nanostructured hydrogels show superior electroconductivity while mimicking the mechanical characteristics of the brain tissue. Furthermore, in vitro biological tests performed by culturing neural progenitor cells demonstrate the biocompatibility of hydrogels along with neuronal differentiation. In vivo chronic neuroinflammation tests on a mouse model show no adverse immune response toward the nanostructured hydrogel-based neural interface. Additionally, electrocorticography acquisitions indicate that the proposed platform permits long-term efficient recordings of neural signals, revealing the suitability of the system as a chronic neural biointerface.

brain−machine interface,conductive hydrogels,nanostructured biomaterials,in vitro and in vivo biocompatibility,long-term neural recording

Current treatments of degenerated intervertebral discs often provide only temporary relief or address specific causes, necessitating the exploration of alternative therapies. Cell-based regenerative approaches showed promise in many clinical trials, but
limitations such as cell death during injection and a harsh disk environment hinder their effectiveness. Injectable microscaffolds offer a solution by providing a supportive microenvironment for cell delivery and enhancing bioactivity. This study evaluated the
safety and feasibility of electrospun nanofibrous microscaffolds modified with chitosan (CH) and chondroitin sulfate (CS) for treating degenerated NP tissue in a large animal model. The microscaffolds facilitated cell attachment and acted as an effective delivery system, preventing cell leakage under a high disc pressure. Combining microscaffolds with bone marrow-derived mesenchymal stromal cells demonstrated no cytotoxic effects and proliferation over the entire microscaffolds. The administration of cells attached to microscaffolds into the NP positively influenced the regeneration process of the intervertebral disc. Injectable poly(L-lactide-co-glycolide) and poly(L-lactide) microscaffolds enriched with CH or CS, having a fibrous structure, showed the potential to promote intervertebral disc regeneration. These features collectively address critical challenges in the fields of tissue engineering and regenerative medicine, particularly in the context of intervertebral disc degeneration.

microscaffolds,cell carriers,injectable biomaterials,intervertebral disc,laser micromachining,electrospinning

The emergence of portable electronics in miniaturized and intelligent devices demands high-performance supercapacitors (SC) and batteries as power sources. For the fabrication of such energy storage devices, conducting polymers (CPs) have significant advantages due to their high theoretical capacitive performance and conductivity. In this work, we developed two CPs including polyaniline and polythiophene through a low-cost chemically synthesized approach and the film-by-spin coating method. The structural and morphological properties of the CPs are analyzed using Fourier-transform infrared spectroscopy (FTIR), contact angle measurement, and scanning electron microscopy (SEM). Based on these CPs, novel pristine polyaniline and polythiophene-based SCs (PASC and PTSC) are developed. The prepared CPs contribute to high electrochemical performances due to their high conductive nature of the electrode and conjugated polymer materials reaction. Hence both electrochemical double-layer formation and pseudocapacitance contributed to the energy-storing performances of the device. Electrochemical impedance spectroscopic analysis (0.1 Hz to 100 kHz) demonstrates faster ionic exchange and high capacitance of the PASC electrode as compared to PTSC in H3PO4 electrolyte. The PASC devices exhibit specific capacitance of 13.22 mF·cm−2 with energy and power densities of 1.175 μW·h·cm−2 and 4.99 μW·cm−2 at a current of 50 μA. Compared to PTSC (specific capacitance 3.30 mF·cm−2) the PASC shows four times higher specific capacitance due to its improved surface, structural and electrical properties. The electrochemical performance reveals the superior SC performance for this type of CP electrode.

Conductive polymers, Spin coating, Polyaniline, Polythiophene, Supercapacitor, Electrochemical performances

Over the last few years, traditional drug delivery systems (DDSs) have been transformed into smart DDSs. Recent advancements in biomedical nanotech-nology resulted in introducing stimuli-responsiveness to drug vehicles. Nano-
platforms can enhance drug release efficacy while reducing the side effects of drugs by taking advantage of the responses to specific internal or external stim-uli. In this study, we developed an electrospun nanofibrous photo-responsive DDSs. The photo-responsivity of the platform enables on-demand elevated drug release. Furthermore, it can provide a sustained release profile and pre-vent burst release and high concentrations of drugs. A coaxial electrospinning setup paired with an electrospraying technique is used to fabricate core-shell PVA-PLGA nanofibers decorated with plasmonic nanoparticles. The fabricated
nanofibers have a hydrophilic PVA and Rhodamine-B (RhB) core, while the shell is hydrophobic PLGA decorated with gold nanorods (Au NRs). The presence of plasmonic nanoparticles enables the platform to twice the amount of drug release besides exhibiting a long-term release. Investigations into the photo-responsive release mechanism demonstrate the system's potential as a “smart” drug delivery platform.

electrospun core-shell nanofibers,NIR-light activation,on-demand drug release,plasmonic nanoparticles,stimuli-responsive nanomaterials

In recent times, the use of personal protective equipment, such as face masks or respirators, is becoming more and more critically important because of common pollution; furthermore, face masks have become a necessary element in the global fight against the COVID-19 pandemic. For this reason, the main mission of scientists has become the development of face masks with exceptional properties that will enhance their performance. The versatility of electrospun polymer nanofibers has determined their suitability as a material for constructing “smart” filter media. This paper provides an overview of the research carried out on nanofibrous filters obtained by electrospinning. The progressive development of the next generation of face masks whose unique properties can be activated in response to a specific external stimulus is highlighted. Thanks to additional components incorporated into the fiber structure, filters can, for example, acquire antibacterial or antiviral properties, self-sterilize the structure, and store the energy generated by users. Despite the discovery of several fascinating possibilities, some of them remain unexplored. Stimuli-responsive filters have the potential to become products of large-scale availability and great importance to society as a whole.

nanostructured face masks, stimuli-responsive nanomaterials, electrospun nanofibers, active filtration, smart filters, COVID-19, antipathogen

Over the last decade, nanotechnology and nanomaterials have attracted enormous interest due to the rising number of their applications in solar cells. A fascinating strategy to increase the efficiency of organic solar cells is the use of tailor-designed buffer layers to improve the charge transport process. High-efficiency bulk heterojunction (BHJ) solar cells have been obtained by introducing hollow core polyaniline (PANI) nanofibers as a buffer layer. An improved power conversion efficiency in polymer solar cells (PSCs) was demonstrated through the incorporation of electrospun hollow core PANI nanofibers positioned between the active layer and the electrode. PANI hollow nanofibers improved buffer layer structural properties, enhanced optical absorption, and induced a more balanced charge transfer process. Solar cell photovoltaic parameters also showed higher open-circuit voltage (+ 40.3%) and higher power conversion efficiency (+ 48.5%) than conventional architecture BHJ solar cells. Furthermore, the photovoltaic cell developed achieved the highest reported efficiency value ever reached for an electrospun fiber-based solar cell (PCE = 6.85%). Our results indicated that PANI hollow core nanostructures may be considered an effective material for high-performance PSCs and potentially applicable to other fields, such as fuel cells and sensors.

The influence of reduction temperature on the electromechanical properties and actuation behavior of polydimethylsiloxane (PDMS) dielectric elastomer containing the thermally reduced graphene oxide (rGO) with different surface chemistry has been systematically investigated. A set of rGO nanosheets was prepared by thermal reduction of graphene oxide (GO) at four temperatures (150, 200, 300, and 400 °C). The dielectric permittivity, dielectric loss, and elastic modulus of PDMS composites were increased, while the electrical breakdown strength of composites was decreased with an increase of the reduction temperature of GO. A thermodynamic model applied for studying the electromechanical deformation and stability of PDMS/GO(rGO-x) dielectric elastomer composites showed that the optimum value of the break-point was observed in PDMS/rGO-300. It is shown for the first time that the variation of electromechanical instability and recovery behavior are attributed to the surface chemistry of rGOs. A critical reduction temperature is observed at 300 °C which can be considered as proper rGO nanosheets for electromechanical applications. By employing an equivalent circuit on impedance spectroscopy, the interfacial polarization is recognized as the dominant mechanism rather than the intrinsic polarization of the matrix and nanosheets. Noteworthy, PDMS composites containing rGO, reduced at higher temperatures, have more interfacial polarized charges at the interface.

Dielectric Elastomer ,Polymer Composite ,Graphene Oxide (GO),Thermally Reduced Graphene Oxide (rGO) ,Electromechanical Properties,Actuation Behavior,Electromechanical Instability

In recent years, novel strategies and approaches to develop antimicrobial biomaterials have attracted increasing attention, targeting multi-functional systems to eliminate bacteria from membranes, surfaces, medical devices, infected sites, contact lenses, etc. More specifically, eradicating bacteria (both resident and exogenous) at the wound site is crucial to guarantee fast and effective wound healing without complications, while sterilization of personal protective equipment (e.g., face masks) makes it possible the safe re-use.[1,2] In this frame, photothermal therapy holds great potential since it can kill pathogenic bacteria with minimal invasiveness.[3]

In this study, plasmonic nanoparticles have been combined with biopolymers to provide the system with bactericide functions. More in detail, plasmonic gold nanorods (AuNRs) are encapsulated into electrospun matrices made of poly(lactic-co-glycolic acid) or polyacrylonitrile by loading into the polymeric solution prior to electrospinning or spraying on the already spun material to obtain the final composites (Figure 1A). The photo-thermal properties of the incorporated AuNRs are exploited to activate the near infrared (NIR)-mediated temperature response upon exposure to NIR light. By reaching a temperature > 55°C, the eradication of 99.5% of bacteria is achieved (Figure 1B), while the stability of the composite materials is maintained. Additionally, in vitro biocompatibility tests performed by culturing fibroblast cells onto the proposed systems show suitable biological properties with no toxic or inflammatory reactions. Taking into account the results, the biocompatible photothermal-responsive nanocomposites reveal their potential in photothermal therapy as a wound dressing and face mask coating.