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.

Recently, there has been a surge of interest in developing new types of photothermal materials driven by the ongoing demand for efficient energy conversion, environmental concerns, and the need for sustainable solutions. However, many existing photothermal materials face limitations such as high production costs or narrow absorption bands, hindering their widespread application. In response to these challenges, researchers have redirected their focus toward harnessing the untapped potential of organic waste-derived and bioderived materials. These materials, with photothermal properties derived from their intrinsic composition or transformative processes, offer a sustainable and cost-effective alternative. This review provides an extended categorization of organic waste-derived and bioderived materials based on their origin. Additionally, we investigate the mechanisms underlying the photothermal properties of these materials. Key findings highlight their high photothermal efficiency and versatility in applications such as water and energy harvesting, desalination, biomedical applications, deicing, waste treatment, and environmental remediation. Through their versatile utilization, they demonstrate immense potential in fostering sustainability and support the transition toward a greener and more resilient future. The authors’ perspective on the challenges and potentials of platforms based on these materials is also included, highlighting their immense potential for real-world implementation.

photothermal materials, organic waste valorization, bioderived materials

Recent advances in the field of skin patches have promoted the development of wearable and implantable bioelectronics for long-term, continuous healthcare management and targeted therapy. However, the design of electronic skin (e-skin) patches with stretchable components is still challenging and requires an in-depth understanding of the skin-attachable substrate layer, functional biomaterials and advanced self-powered electronics. In this comprehensive review, we present the evolution of skin patches from functional nanostructured materials to multi-functional and stimuli-responsive patches towards flexible substrates and emerging biomaterials for e-skin patches, including the material selection, structure design and promising applications. Stretchable sensors and self-powered e-skin patches are also discussed, ranging from electrical stimulation for clinical procedures to continuous health monitoring and integrated systems for comprehensive healthcare management. Moreover, an integrated energy harvester with bioelectronics enables the fabrication of self-powered electronic skin patches, which can effectively solve the energy supply and overcome the drawbacks induced by bulky battery-driven devices. However, to realize the full potential offered by these advancements, several challenges must be addressed for next-generation e-skin patches. Finally, future opportunities and positive outlooks are presented on the future directions of bioelectronics. It is believed that innovative material design, structure engineering, and in-depth study of fundamental principles can foster the rapid evolution of electronic skin patches, and eventually enable self-powered close-looped bioelectronic systems to benefit mankind.

In situ forming injectable hydrogels hold great potential for the treatment of irregular wounds. However, their practical applications were hindered by long gelation time, poor mechanical performance, and a lack of a natural extracellular matrix structure. Herein, amino-modified electrospun poly(lactic-co-glycolic acid) (APLGA) short fibers with uniform distribution were introduced into gelatin methacrylate/oxidized dextran (GM/ODex) hydrogels. In comparison with the fiber aggregation structure in the PLGA fiber-incorporated hydrogels, the hydrogels with APLGA fibers possessed a uniform porous structure. The highly dispersed APLGA short fibers accelerated the sol–gel phase transition of the hydrogel due to the formation of dynamic Schiff-base bonds between the fibers and hydrogels. Furthermore, in combination with UV-assisted crosslinking, a rapid gelation time of 90 s was achieved for the double-crosslinked hydrogels. The addition of APLGA short fibers as fillers and the formation of the double-crosslinking network enhanced the mechanical performance of the hydrogels. Furthermore, the fiber–hydrogel composites exhibited favorable injectability, excellent biocompatibility, and improved cell infiltration. In vivo assessment indicated that the GM/ODex-APLGA hydrogels successfully filled the full-thickness defects and improved wound healing. This work demonstrates a promising solution for the treatment of irregular wounds.

One of the most fascinating areas in the field of smart biopolymers is biomolecule sensing. Accordingly, multifunctional biomimetic, biocompatible, and stimuli-responsive materials based on hydrogels have attracted much interest. Within this framework, the design of nanostructured materials that do not require any external energy source is beneficial for developing a platform for sensing glucose in body fluids. In this article, we report the realization and application of an innovative platform consisting of two outer layers of a nanocomposite plasmonic hydrogel plus one inner layer of electrospun mat fabricated by electrospinning, where the outer layers exploit photoinitiated free radical polymerization, obtaining a compact and stable device. Inspired by the exceptional features of chameleon skin, plasmonic silver nanocubes are embedded into a poly(N-isopropylacrylamide)-based hydrogel network to obtain enhanced thermoresponsive and antibacterial properties. The introduction of an electrospun mat creates a compatible environment for the homogeneous hydrogel coating while imparting excellent mechanical and structural properties to the final system. Chemical, morphological, and optical characterizations were performed to investigate the structure of the layers and the multifunctional platform. The synergetic effect of the nanostructured system’s photothermal responsivity and antibacterial properties was evaluated. The sensing features associated with the optical properties of silver nanocubes revealed that the proposed multifunctional system is a promising candidate for glucose-sensing applications.

Adhesive and stretchable nanofibrous hydrogels have attracted extensive attraction in wound dressings, especially for joint wound treatment. However, adhesive hydrogels tend to display poor stretchable behavior. It is still a significant challenge to integrate excellent adhesiveness and stretchability in a nanofibrous hydrogel. Herein, a highly adhesive, stretchable, and breathable nanofibrous hydrogel was developed via an in situ hybrid cross-linking strategy of electrospun nanofibers comprising dopamine (DA) and gelatin methacryloyl (GelMA). Benefiting from the balance of cohesion and adhesion based on photocross-linking of methacryloyl (MA) groups in GelMA and the chemical/physical reaction between GelMA and DA, the nanofibrous hydrogels exhibited tunable adhesive and mechanical properties through varying MA substitution degrees of GelMA. The optimized GelMA60-DA exhibited 2.0 times larger tensile strength (2.4 MPa) with an elongation of about 200%, 2.3 times greater adhesive strength (9.1 kPa) on porcine skin, and 3.1 times higher water vapor transmission rate (10.9 kg m–2 d–1) compared with gelatin nanofibrous hydrogels. In parallel, the GelMA60-DA nanofibrous hydrogels could facilitate cell growth and accelerate wound healing. This work presented a type of breathable nanofibrous hydrogels with excellent adhesive and stretchable capacities, showing great promise as wound dressings.

nanofibrous hydrogels, hybrid cross-linking, adhesivity, stretchability, breathable capability

The Coronavirus disease 2019 (COVID‐19) emergency has demonstrated that the utilization of face masks plays a critical role in limiting the outbreaks. Healthcare professionals utilize masks all day long without replacing them very frequently, thus representing a source of cross‐infection for patients and themselves. Nanotechnology is a powerful tool with the capability to produce nanomaterials with unique physicochemical and anti‐pathogen properties. Here, we outline how to realize non‐disposable and highly comfortable respirators with light‐triggered self‐disinfection ability by bridging bioactive nanofiber properties and stimuli‐responsive nanomaterials. The visionary road highlighted in this Concept is based on the possibility to develop a new generation of masks based on multifunctional membranes where the presence of nanoclusters and plasmonic nanoparticles arranged in a hierarchical structure enables the realization of a chemically‐driven and on‐demand anti‐pathogen activities. Multilayer electrospun membranes have the ability to dissipate humidity present within the mask, enhancing the wearability and usability. The photo‐thermal disinfected membrane is the core of these 3D printed and reusable masks with moisture pump capability. Personalized face masks with smart nano‐assisted destruction of pathogens will bring enormous advantages to the entire global community, especially for front‐line personnel, and will open up great opportunities for innovative medical applications.

face masks, light-responsive nanomaterials, anti-pathogen, electrospinning, digitally personalized

In recent years, the main quest of science has been the pioneering of the groundbreaking biomedical strategies needed for achieving a personalized medicine. Ribonucleic acids (RNAs) are outstanding bioactive macromolecules identified as pivotal actors in regulating a wide range of biochemical pathways. The ability to intimately control the cell fate and tissue activities makes RNA-based drugs the most fascinating family of bioactive agents. However, achieving a widespread application of RNA therapeutics in humans is still a challenging feat, due to both the instability of naked RNA and the presence of biological barriers aimed at hindering the entrance of RNA into cells. Recently, material scientists’ enormous efforts have led to the development of various classes of nanostructured carriers customized to overcome these limitations. This work systematically reviews the current advances in developing the next generation of drugs based on nanotechnology-assisted RNA delivery. The features of the most used RNA molecules are presented, together with the development strategies and properties of nanostructured vehicles. Also provided is an in-depth overview of various therapeutic applications of the presented systems, including coronavirus disease vaccines and the newest trends in the field. Lastly, emerging challenges and future perspectives for nanotechnology-mediated RNA therapies are discussed.

The poor intrinsic mechanical properties of chitosan hydrogels have greatly hindered their practical applications. Inspired by nature, we proposed a strategy to enhance the mechanical properties of chitosan hydrogels by construction of a nanofibrous and cellular architecture in the hydrogel without toxic chemical crosslinking. To this end, electrospun nanofibers including cellulose acetate, polyacrylonitrile, and SiO2 nanofibers were introduced into chitosan hydrogels by homogenous dispersion and lyophilization. With the addition of 30% cellulose acetate nanofibers, the cellular structure could be maintained even in water without crosslinking, and integration of 60% of the nanofibers could guarantee the free-standing structure of the chitosan hydrogel with a low solid content of 1%. Moreover, the SiO2 nanofiber-reinforced chitosan (SiO2 NF/CS) three-dimensional (3D) matrices exhibit complete shape recovery from 80% compressive strain and excellent injectability. The cellular architecture and nanofibrous structure in the SiO2 NF/CS matrices are beneficial for human mesenchymal stem cell adhesion and stretching. Furthermore, the SiO2 NF/CS matrices can also act as powerful vehicles for drug delivery. As an example, bone morphogenetic protein 2 could be immobilized on SiO2 NF/CS matrices to induce osteogenic differentiation. Together, the electrospun nanofiber-reinforced 3D chitosan matrices exhibited improved mechanical properties and enhanced biofunctionality, showing great potential in tissue engineering.

chitosan hydrogel, electrospun nanofiber, mechanical property, nanofibrous matrix, tissue engineering

Body tissues and organs have complex functions which undergo intrinsic changes during medical treatments. For the development of ideal drug delivery systems, understanding the biological tissue activities is necessary to be able to design materials capable of changing their properties over time, on the basis of the patient's tissue needs. In this study, a nanofibrous thermal‐responsive drug delivery system is developed. The thermo‐responsivity of the system makes it possible to self‐regulate the release of bioactive molecules, while reducing the drug delivery at early stages, thus avoiding high concentrations of drugs which may be toxic for healthy cells. A co‐axial electrospinning technique is used to fabricate core–shell cross‐linked copolymer poly(N‐isopropylacrylamide‐co‐N‐isopropylmethacrylamide) (P(NIPAAm‐co‐NIPMAAm)) hydrogel‐based nanofibers. The obtained nanofibers are made of a core of thermo‐responsive hydrogel containing a drug model, while the outer shell is made of poly‐l‐lactide‐co‐caprolactone (PLCL). The custom‐made electrospinning apparatus enables the in situ cross‐linking of P(NIPAAm‐co‐NIPMAAm) hydrogel into a nanoscale confined space, which improves the electrospun nanofiber drug dosing process, by reducing its provision and allowing a self‐regulated release control. The mechanism of the temperature‐induced release control is studied in depth, and it is shown that the system is a promising candidate as a "smart" drug delivery platform.

biomimetic nanomaterials, electrospun core–shell nanofibers, hierarchical nanostructures, smart drug delivery, thermo‐responsive hydrogels