Multi-engineered Graphene Extended-Gate Field-Effect Transistor for Peroxynitrite Sensing in Alzheimer's Disease.

The expression of ß-amyloid peptides (Aß), a pathological indicator of Alzheimer's disease (AD), was reported to be inapparent in the early stage of AD. While peroxynitrite (ONOO-) is produced excessively and emerges earlier than Aß plaques in the progression of AD, it is thus significant to sensitively detect ONOO- for early diagnosis of AD and its pathological research. Herein, we unveiled an integrated sensor for monitoring ONOO-, which consisted of a commercially available field-effect transistor (FET) and a high-performance multi-engineered graphene extended-gate (EG) electrode. In the configuration of the presented EG electrode, laser-induced graphene (LIG) intercalated with MnO2 nanoparticles (MnO2/LIG) can improve the electrical properties of LIG and the sensitivity of the sensor, and graphene oxide (GO)-MnO2/Hemin nanozyme with ONOO- isomerase activity can selectively trigger the isomerization of ONOO- to NO3-. With this synergistic effect, our EG-FET sensor can respond to the ONOO- with high sensitivity and selectivity. Moreover, taking advantage of our EG-FET sensor, we modularly assembled a portable sensing platform for wireless tracking ONOO- levels in the brain tissue of AD transgenic mice at earlier stages before massive Aß plaques appeared, and we systematically explored the complex role of ONOO- in the occurrence and development of AD.

Tailoring Food Biopolymers into Biogels for Regenerative Wound Healing and Versatile Skin Bioelectronics.

An increasing utilization of wound-related therapeutic materials and skin bioelectronics urges the development of multifunctional biogels for personal therapy and health management. Nevertheless, conventional dressings and skin bioelectronics with single function, mechanical mismatches, and impracticality severely limit their widespread applications in clinical. Herein, we explore a gelling mechanism, fabrication method, and functionalization for broadly applicable food biopolymers-based biogels that unite the challenging needs of elastic yet injectable wound dressing and skin bioelectronics in a single system. We combine our biogels with functional nanomaterials, such as cuttlefish ink nanoparticles and silver nanowires, to endow the biogels with reactive oxygen species scavenging capacity and electrical conductivity, and finally realized the improvement in diabetic wound microenvironment and the monitoring of electrophysiological signals on skin. This line of research work sheds light on preparing food biopolymers-based biogels with multifunctional integration of wound treatment and smart medical treatment.

Debonding-On-Demand Polymeric Wound Patches for Minimal Adhesion and Clinical Communication.

Herein, a multifunctional bilayer wound patch is developed by integrating a debonding-on-demand polymeric tissue adhesive (DDPTA) with an ionic conducting elastomer (ICE). As a skin adhesive layer, the DDPTA is soft and adherent at skin temperature but hard and non-tacky when cooled, so it provides unique temperature-triggered quick adhesion and non-forced detachment from the skin. During use, the dense surface of the DDPTA prevents blood infiltration and reduces unnecessary blood loss with gentle pressing. Moreover, its hydrophobic matrix helps to repel blood and prevents the formation of clots, thus precluding wound tearing during its removal. This unique feature enables the DDPTA to avoid the severe deficiencies of hydrophilic adhesives, providing a reliable solution for a wide range of secondary wound injuries. The DDPTA is versatile in that it can be covered with ICE to configure a DDPTA@ICE patch for initiating non-verbal communication systems by the fingers, leading toward sign language recognition and a remote clinical alarm system. This multifunctional wound patch with debonding-on-demand can promote a new style of tissue sealant for convenient clinical communication.

Wound Dressing: From Nanomaterials to Diagnostic Dressings and Healing Evaluations.

Wound dressings based on nanomaterials play a crucial role in wound treatment and are widely used in a whole range of medical settings, from minor to life-threatening tissue injuries. This article presents an educational review on the accumulating knowledge in this multidisciplinary area to lay out the challenges and opportunities that lie ahead and ignite the further and faster development of clinically valuable technologies. The review analyzes the functional advantages of nanomaterial-based gauzes and hydrogels as well as hybrid structures thereof. On this basis, the review presents state-of-the-art advances to transfer the (semi)blind approaches to the evaluation of a wound state to smart wound dressings that enable real-time monitoring and diagnostic functions that could help in wound evaluation during healing. This review explores the translation of nanomaterial-based wound dressings and related medical aspects into real-world use. The ongoing challenges and future opportunities associated with nanomaterial-based wound dressings and related clinical decisions are presented and reviewed.

Polydopamine nanoparticle-dotted food gum hydrogel with excellent antibacterial activity and rapid shape adaptability for accelerated bacteria-infected wound healing.

Most commonly used wound dressings have severe problems, such as an inability to adapt to wound shape or a lack of antibacterial capacity, affecting their ability to meet the requirements of clinical applications. Here, a nanocomposite hydrogel (XKP) is developed by introducing polydopamine nanoparticles (PDA NPs) into a food gum matrix (XK, consisting of xanthan gum and konjac glucomannan, both FDA-approved food thickening agents) for skin wound healing. In this system, the embedded PDA NPs not only interact with the food gum matrix to form a hydrogel with excellent mechanical strength, but also act as photothermal transduction agents to convert near-infrared laser radiation to heat, thereby triggering bacterial death. Moreover, the XKP hydrogel has high elasticity and tunable water content, enabling it to adapt to the shape of the wound and insulate it, providing a moist environment suitable for healing. In-vivo skin wound healing results clearly demonstrate that XKP can significantly accelerate the healing of wounds by reducing the inflammatory response and promoting vascular reconstruction. In summary, this strategy provides a simple and practical method to overcome the drawbacks of traditional wound dressings, and provides further options when choosing suitable wound healing materials for clinical applications.

Mussel-inspired agarose hydrogel scaffolds for skin tissue engineering.

Polysaccharide hydrogels are widely used in tissue engineering because of their superior biocompatibility and low immunogenicity. However, many of these hydrogels are unrealistic for practical applications as the cost of raw materials is high, and the fabrication steps are tedious. This study focuses on the facile fabrication and optimization of agarose-polydopamine hydrogel (APG) scaffolds for skin wound healing. The first study objective was to evaluate the effects of polydopamine (PDA) on the mechanical properties, water holding capacity and cell adhesiveness of APG. We observed that APG showed decreased rigidity and increased water content with the addition of PDA. Most importantly, decreased rigidity translated into significant increase in cell adhesiveness. Next, the slow biodegradability and high biocompatibility of APG with the highest PDA content (APG3) was confirmed. In addition, APG3 promoted full-thickness skin defect healing by accelerating collagen deposition and promoting angiogenesis. Altogether, we have developed a straightforward and efficient strategy to construct functional APG scaffold for skin tissue engineering, which has translation potentials in clinical practice.

Polydopamine/montmorillonite-embedded pullulan hydrogels as efficient adsorbents for removing crystal violet.

Both secondary pollution and the low mechanical strength of adsorbents have severely impeded the practical application of adsorption methods in the dye wastewater treatment. In this work, we innovatively synthesized a composite hydrogel adsorbent by incorporating polydopamine (PDA) and montmorillonite (MMT) into the pullulan hydrogel matrix for dye adsorption. First, the successful formation of the resultant adsorbents was verified by Fourier-transform infrared spectroscopy and scanning electron microscope elemental mapping analysis. Then, several physicochemical properties (such as thermal and swelling properties, microarchitecture, and mechanical strength) of the five prepared adsorbents (PM1-PM5) were investigated. These results demonstrated the adsorbents had tunable properties, which can be achieved by adjusting the PDA/MMT mass ratio. Next, the dye adsorption performance was systematically explored. The resultant adsorbent (PM3) had a maximum adsorption capacity of 112.45 mg/g and its adsorption data was best described by a Langmuir isotherm and pseudo-second-order kinetic. Finally, the adsorption mechanisms and potential commercial practicability of the adsorbent were studied. Altogether, the designed adsorbent could effectively avoid generating the secondary pollution typical of adsorbents and it displayed excellent mechanical strength, thus opening up a new horizon in mitigating environmental pollution from textile industries.

Polydopamine-incorporated dextran hydrogel drug carrier with tailorable structure for wound healing.

Effective methods to treat bacterial infections are highly desired as the abuse of antibiotics has caused multidrug-resistant. Polysaccharide hydrogel-based drug delivery systems possessing inherent large surface area and biocompatibility attributes provide a promising strategy for effective use of antibiotics. Here, we presented an effective method for fabricating macroporous polysaccharide hydrogels composed of dextran (DP) and polydopamine (PDA) for controlled release of antibiotics. The physicochemical properties of resulting DP hydrogels were systematically evaluated by measuring their swelling, viscoelasticity, morphology, sorption and thermal stability, and we could control these properties through simply changing the PDA concentration in a pre-gel solution. The low cytotoxicity of DP hydrogels was demonstrated through a co-culture with mouse fibroblast cells. Moreover, in vitro/vivo antibacterial properties of the drug-loading DP hydrogels were evaluated, and they exhibited good antibacterial and healing performances. We believe that the proposed strategy for facilitation and optimization of polysaccharide hydrogels could offer more hydrogel dressings when choosing suitable carriers for sustained release of antibiotics.

Sustainable, flexible and biocompatible hydrogels derived from microbial polysaccharides with tailorable structures for tissue engineering.

Polysaccharides derived from microorganisms have received considerable attention in designing hydrogel materials. However, most microbial polysaccharide-constructed hydrogels evaluated in preclinical trials are not favorable candidates for biomedical applications owing to concerns regarding poor mechanical strength and complicated fabrication process. Herein, we describe a new polysaccharide hydrogel scaffold containing salecan together with gellan gum network as the polymeric matrix. Properly controlling the physical and chemical properties including swelling, water release, thermal stability, viscoelasticity and morphology of the resulting gel are easily achieved by simply changing the salecan/gellan gum ratios. Notably, these salecan/gellan gum scaffolds friendly support cell survival and proliferation. More significantly, we have systematically evaluated these developed hydrogels for the biocompatible experiments in vitro and in vivo and results indicated the products are non-toxic. Taken together, such hydrogels derived from microbial polysaccharides and readily synthesized through a one-step mixing protocol have translational potentials in the clinic serving as cell devices for tissue engineering.

Macroporous Hydrogel Scaffolds with Tunable Physicochemical Properties for Tissue Engineering Constructed Using Renewable Polysaccharides.

Polysaccharides have recently attracted increasing attention in the construction of hydrogel devices for biomedical applications. However, polysaccharide-based hydrogels are not suitable for most preclinical applications because of their limited mechanical properties and poor tunability. In this study, we employed a simple and eco-friendly approach to producing a macroporous polysaccharide hydrogel composed of salecan and κ-carrageenan without the use of toxic chemicals. We evaluated the physicochemical properties of the obtained salecan/κ-carrageenan hydrogel and found that its viscoelasticity, morphology, swelling, and thermal stability could be simply controlled by changing the polysaccharide dose in the pre-gel solution. The co-incubation of the fabricated hydrogel with mouse fibroblast cells demonstrated that the hydrogel can support cell adhesion, migration, and growth. Moreover, the hydrogel exhibited good biocompatibility in vivo. Overall, the findings provide a new strategy for the fabrication and optimization of polysaccharide-based hydrogel scaffolds for application in tissue engineering.

Biocompatible Hydrogels Based on Food Gums with Tunable Physicochemical Properties as Scaffolds for Cell Culture.

Hydrogels composed of food gums have gained attention for future biomedical applications, such as targeted delivery and tissue engineering. For their translation to clinical utilization, reliable biocompatibility, sufficient mechanical performance, and tunable structure of polysaccharide hydrogels are required aspects. In this work, we report a unique hybrid polysaccharide hydrogel composed of salecan and curdlan, in which the former is a thickening agent and the latter serves as a network matrix. The physicochemical properties, such as mechanical strength, thermal stability, swelling, and morphology, of the developed composite hydrogel can be accurately modulated by varying the polysaccharide content. Importantly, cytotoxicity assays show the non-toxicity of this hybrid hydrogel. Furthermore, this hydrogel system can support cell proliferation, migration, and function. Altogether, our work proposes a new strategy to build a polysaccharide-constructed hydrogel scaffold, which holds much promise for tissue engineering in terms of cell engraftment, survival, proliferation, and function.

Efficient decontamination of heavy metals from aqueous solution using pullulan/polydopamine hydrogels.

Designing a new adsorbent with recyclability, high efficiency and biodegradability is important for treating heavy metals contamination but remains a severe challenge. In this work, a novel type of hydrogel biosorbents based on pullulan and polydopamine were designed for heavy metal ions removal from aqueous solution. The physicochemical properties of the prepared pullulan/polydopamine (Pu/PDA) hydrogels were fully characterized by thermal gravimetric analysis, Fourier transform infrared spectroscopy, rheology, scanning electron microscopy, swelling and compression tests. We observed that their mechanical strength, pore size, water absorption and retention properties could be nicely controlled by adjusting the PDA concentration in the pre-gel solution. Subsequently, the adsorption ability of designed Pu/PDA hydrogels to Cu2+, Co2+ and Ni2+ was investigated in detail. These hydrogels presented excellent adsorption capability for heavy metal ions and matched well with the pseudo-second-order kinetic model and Freundlich isotherm model. Overall, having tunable physicochemical properties coupled with the high absorption ability for heavy metal ions, these Pu/PDA hydrogels may be a promising strategy for removal of pollutants from aqueous solution.

Facile formation of salecan/agarose hydrogels with tunable structural properties for cell culture.

Salecan polysaccharide produced by Agrobacterium sp. ZX09 is an attractive biopolymer to construct hydrogel scaffolds for cell culture. However, some limitations such as poor mechanical performance, complicated fabrication process and slow gelation times still exist in the biomedical applications of microbial-based salecan polysaccharide hydrogels. Here, a series of polysaccharide hydrogels composed of salecan and agarose with adjustable structural properties are designed. The resultant hybrid salecan/agarose hydrogels exhibit controllable physical and chemical properties including thermal stability, water uptake, mechanical strength and microarchitecture, which can be readily realized with minimum change of the polysaccharide content. Furthermore, cytotoxicity assays reveal that the designed composite hydrogels are non-toxic. More importantly, these hydrogels support cell survival, proliferation, and migration. Together, this work opens up a new avenue to build polysaccharide hydrogel platforms for tissue engineering.

Highly efficient dye decontamination via microbial salecan polysaccharide-based gels.

Wastewater treatment materials that combine high decontamination performance, ease of use and economic production are highly desirable for practical applications. Herein, we fabricated a low-cost and recyclable bio-adsorbent based on a microbial polysaccharide (salecan) for efficient removal of methyl violet (MV) from wastewater. The success fabrication and the properties (such as thermal stability, microarchitecture, mechanical strength and water uptake) of the adsorbent had been investigated, and the hydrogels were found to have tunable properties by simple adjusting the salecan dose in hydrogel composition. Adsorption data displayed that the adsorption of MV followed the pseudo second-order kinetic model (R2 = 0.99015) and Freundlich isotherm model (R2 = 0.99221) with a maximum adsorption capacity of 178.9 mg/g. Moreover, salecan-based hydrogels showed a good reversibility in adsorption-desorption cycles. These features indicate that salecan-based bio-adsorbent may be a promising device for dye removal from dyeing waste water.

Construction of macroporous salecan polysaccharide-based adsorbents for wastewater remediation.

Adsorbents fabricated with biopolymer are extremely fascinating from the material design aspect, with numerous advantages like excellent biocompatibility, good biodegradability and availability at low cost. In this paper, a novel salecan polysaccharide-based biosorbent was designed for removal of Cd2+ ions from aqueous solutions. The resulting adsorbent was characterized by FTIR, XRD, TGA, SEM, rheology and swelling measurements. Adsorption of Cd2+ onto the salecan biosorbent was evaluated taking into account salecan amount, sorbent dosage, solution pH, initial Cd2+ concentration and contact time. Pseudo-second-order kinetic model and Weber-Morris intra-particle diffusion model well fitted the kinetic results, suggesting chemisorption and intra-particle diffusion as the most probable adsorption mechanism. Meanwhile, the equilibrium adsorption data was nicely described by Langmuir isotherm model with a maximum adsorption capacity of 170.1 mg Cd2+ per gram of sample. Finally, the salecan biosorbent exhibited an excellent reusability and 89.2% of the original sorption ability remained after 6 cycles. The present findings suggest that salecan-based biosorbents have potential for application as a wastewater remediation device.

Removal of copper ions from water using polysaccharide-constructed hydrogels.

Polysaccharides are an important class of materials that are often exploited in the fields of food, agriculture, biomedical engineering and wastewater treatment owing to their unique and tunable properties. In this work, we utilize an inexpensive and sustainable extracellular polysaccharide salecan (EPS), which is produced by bacterium Agrobacterium sp. ZX09, as a hydrogel matrix, poly(3-sulfopropyl methacrylate potassium salt) (PSM) as side chains to fabricate EPS-grafted-PSM adsorbents through a simple one-pot approach. Scanning electron microscope, X-ray diffraction, Fourier transformed infrared spectroscopy, rheometry and thermogravimetry were conducted to characterize the physicochemical properties of resultant adsorbents. We noticed that EPS not only served as the host chains of network to adjust the water uptake ability of adsorbents, but also endued them with tunable polarity. Further, the adsorption behaviors of developed adsorbents to copper ions (Cu2+) were explored: these gels present high absorption ability for Cu2+ through a chemical adsorption process which well described by Freundlich isotherm and pseudo-second-order kinetic models. In summary, the approach exhibited in this work opens a new avenue to design polysaccharide-based materials for Cu2+ adsorption.