Fabrication of soft piezoelectric nanomaterials is essential for the development of wearable and implantable biomedical devices. However, a big challenge in this soft functional material development ...is to achieve a high piezoelectric property with long‐term stability in a biological environment. Here, a one‐step strategy for fabricating core/shell poly(vinylidene difluoride) (PVDF)/dopamine (DA) nanofibers (NFs) with a very high β‐phase content and self‐aligned polarization is reported. The self‐assembled core/shell structure is believed essential for the formation and alignment of β‐phase PVDF, where strong intermolecular interaction between the NH2 groups on DA and the CF2 groups on PVDF is responsible for aligning the PVDF chains and promoting β‐phase nucleation. The as‐received PVDF/DA NFs exhibit significantly enhanced piezoelectric performance and excellent stability and biocompatibility. An all‐fiber‐based soft sensor is fabricated and tested on human skin and in vivo in mice. The devices show a high sensitivity and accuracy for detecting weak physiological mechanical stimulation from diaphragm motions and blood pulsation. This sensing capability offers great diagnostic potential for the early assessment and prevention of cardiovascular diseases and respiratory disorders.
High‐performance poly(vinylidene difluoride)/dopamine core/shell piezoelectric nanofibers with excellent stability are successfully fabricated by one‐step electrospinning in large scale and quantity, offering an extraordinary building block for developing self‐powered sensor devices to detect weak absolute pressure change from soft tissues in vivo. This sensing capability offers great diagnostic potential for the early assessment and prevention of cardiovascular diseases and respiratory disorders.
The long‐segment peripheral nerve injury (PNI) represents a global medical challenge, leading to incomplete nerve tissue recovery and unsatisfactory functional reconstruction. However, the current ...electrical stimulation (ES) apparatuses fail perfect nerve repair due to their inability of the variable synchronous self‐regulated function with physiological states. It is urgent to develop an implantable ES platform with physiologically adaptive function to provide instantaneous and nerve‐preferred ES. Here, a physiologically self‐regulated electrical signal is generated by integrating a novel tribo/piezoelectric hybrid nanogenerator with a nanoporous nerve guide conduit to construct a fully implantable neural electrical stimulation (FI‐NES) system. The optimal neural ES parameters completely originate from the body itself and are highly self‐responsive to different physiological states. The morphological evaluation, representative protein expression level, and functional reconstruction of the regenerated nerves are conducted to assess the PNI recovery process. Evidence shows that the recovery effect of 15 mm length nerve defects under the guidance of the FI‐NES system is significantly close to the autograft. The designed FI‐NES system provides an effective method for long‐term accelerating the recovery of PNI in vivo and is also appropriate for other tissue injury or neurodegenerative diseases.
A physiologically self‐regulated, fully implantable, battery‐free neural electrical stimulation system is successfully constructed to produce physiologically electrical signals for the acceleration of regeneration and functional recovery of peripheral nerve injury.
Peripheral nerve injury (PNI) remains an intractable challenge in regenerative medicine. Recently, physical cue‐based strategies (e.g., electrical neurostimulation, acoustic radiation, ...electromagnetic bioregulation, as well as directional fiber guiding, etc.) have drawn increasing attention not only as a stimulator for cell functions modulation and fate determination, but also as a morphology‐index for modulating cell phenotype, proliferation, and differentiation, especially for nerve cells. More importantly, the advanced percutaneous power transmission technology, self‐power nanotechnology that leverages piezoelectrical/triboelectricity materials, and focused ultrasound and pulsed electromagnetic field technology exhibit the appealing practice potential for achieving low‐invasive, wireless, and battery‐free neuromodulation. In this review, recent advances of physical cue‐based strategies including electrical, acoustic, magnetic, and morphology for PNI are systematically overviewed, and the open challenges for realizing scalable clinical/commercial transformation and future perspectives of these strategies for PNI are concluded.
In this review, the physical cue‐based strategies, including electrical, acoustic, magnetic, and morphology, to the pathological improvement and regenerative licensing following peripheral nerve injury is systematically outlined. The typical studies are comprehensively summarized and dissected with an emphasis on their strategy conception and realization modalities and envision its prospects in the future.
Despite the boom in the water‐triggered electric power generation technologies, few attempts have been made with a broader horizonyielding the electricity from sweat, which is of great value for ...low‐power‐consumption wearable electronics. Here, an electromechanical coupling and humidity‐actuated two‐in‐one humidity actuator‐driven piezoelectric generator (HAPG) are reported, that can yield continuous electric power from fluctuations in the ambient humidity. It is composed of polyvinyl alcohol (PVA)‐wrapped highly aligned dopamine (DA)/polyvinylidene fluoride (PVDF) shell/core nanofibers (PVA@DA/PVDF NFs). As‐received PVA@DA/PVDF NFs can exchange water with the ambient humidity to perform expansion and contraction and convert them into electric power. An all‐fiber‐based portable HAPG is fabricated and tested on human palm skin. The devices show high sensitivity and accuracy for converting the mental sweating‐derived continuous moisture fluctuations into electric power. This electric power can be stored in capacitors, which is expected to power micro‐ and nano‐electronic devices or be used in electrotherapy such as electrical stimulation to promote wound healing. Beyond this, the obtained voltage profiles exhibit unique features that can reflect the typical sweat damping oscillation curve features.
The electromechanical coupling and humidity‐actuated two‐in‐one polyvinyl alcohol‐wrapped highly aligned polyvinylidene fluoride/dopamine nanofibers are successfully fabricated, which shows high sensitivity and accuracy for sensing fluctuations in the ambient humidity and continuously convert them into electric power. The electrical energy can be stored in capacitors, which are expected to power wearable micro‐ and nano‐electronic devices.
Electrical stimulation (ES) is widely used in physiological and medical sciences, while its application to treat inflammatory skin diseases (ISDs) remains a challenge owing to their natural ...pathological cuticle barrier and lack of an effective combination with chemotherapy to achieve specific immunomodulation. Here, a wearable, battery‐free, multi‐component drug‐loaded electronic microneedle (mD‐eMN) system is developed by integrating remodeled metal microneedles loaded with multi‐component chemical drugs and flexible triboelectric nanogenerators (TENGs). The system can rapidly release drugs into the site of ISDs and then realize an efficient penetration into cell body and specific immunomodulation under the synergism of pulsed electrons originating from the TENG. Also, the pulsed electrons can promote skin tissue homeostasis reconstruction to alleviate the inflammatory process of ISDs. Sufficient evidence shows that a significant skin inflammation regression of psoriasis (a typical ISDs model) is achieved using the mD‐eMN system compared to traditional ES or chemotherapy alone. This innovative wearable mD‐eMN system provides an effective flexible electronic and chemical drug joint technological platform for the treatment of ISDs, which is not only suitable for the treatment of psoriasis in this study but also maybe for other ISDs such as diabetic ulcers and skin tumors.
Electrical stimulation is widely used in physiological and medical sciences, but its application to treat inflammatory skin diseases (ISDs) remains a challenge. Here, a wearable, battery‐free, multi‐component drug‐loaded electronic microneedle system is developed. The system can rapidly release drugs into the site of ISDs and then realize specific immunomodulation under the synergism of pulsed electrons originating from the triboelectric nanogenerators.
Nitrogen (N)-doped graphene (N-substituted or nitrogenated graphene) (NG) has become a new class of graphene material due to its modified properties such as the tunable work function, n-type ...semiconductivity, increasing biocompatibility, and, in particular, the synergistic function with various functional materials. However, the preparation of NG by a simple and effective method is still lacking. The modification of NG mainly depends on the N species and the N content. Thus, we focus on the recent progress in preparing methods of 2D NG and the respective key modulating parameters to modulate the N species and the N content. Furthermore, many effective charactering techniques are covered to accurately analyze the properties of N species, and the distribution and topography of N atoms. Also, we review the effect of N species on graphene, especially, the optical and electronic properties. Since constructing 3D structure is considered a promising strategy to prevent the restacking of 2D NG, the summary for preparing 3D NG is made on the basis of methodology of 2D NG. In a word, this review provides a reference for preparing 2D or 3D NG, modulating and characterizing N species, which are greatly contributed to the NG application.
Blending has been applied to combine the advantages of individual fibers, but the flame retardancy of a blended fiber depends on the interaction of the components. In this work, polyamide (PA) fibers ...were blended with alginate fibers to obtain a blended non-woven fabric and the flame retardancy of the natural/synthetic blended fabric was highlighted. Inspiringly, the two fibers mixed uniformly by the easy-to-handle blending, and the blend’s components did not affect each other’s thermal decomposition. With the addition of 50 wt% alginate fibers, the blended fabrics achieved self-extinguishing without any melt dripping in the vertical flame test, because the melted PA was limited in the area of the charred alginate fibers in the shape of films and bladders; besides, they showed strong decreases in peak heat release rate (56%), total heat release (59%), and total smoke release (66%) compared with PA fibers in the cone calorimeter test. Alginate fibers exhibited both vapor- and condensed-phase flame-retardant activities in the blended system, which was further confirmed by thermogravimetric analysis and thermogravimetry/infrared spectrometry.
Zwitterionic materials are an important class of antifouling biomaterials for various applications. Despite such desirable antifouling properties, molecular-level understanding of the ...structure-property relationship associated with surface chemistry/topology/hydration and antifouling performance still remains to be elucidated. In this work, we computationally studied the packing structure, surface hydration, and antifouling property of three zwitterionic polymer brushes of poly(carboxybetaine methacrylate) (pCBMA), poly(sulfobetaine methacrylate) (pSBMA), and poly((2-(methacryloyloxy)ethyl)phosporylcoline) (pMPC) brushes and a hydrophilic PEG brush using a combination of molecular mechanics (MM), Monte Carlo (MC), molecular dynamics (MD), and steered MD (SMD) simulations. We for the first time determined the optimal packing structures of all polymer brushes from a wide variety of unit cells and chain orientations in a complex energy landscape. Under the optimal packing structures, MD simulations were further conducted to study the structure, dynamics, and orientation of water molecules and protein adsorption on the four polymer brushes, while SMD simulations to study the surface resistance of the polymer brushes to a protein. The collective results consistently revealed that the three zwitterionic brushes exhibited stronger interactions with water molecules and higher surface resistance to a protein than the PEG brush. It was concluded that both the carbon space length between zwitterionic groups and the nature of the anionic groups have a distinct effect on the antifouling performance, leading to the following antifouling ranking of pCBMA > pMPC > pSBMA. This work hopefully provides some structural insights into the design of new antifouling materials beyond traditional PEG-based antifouling materials.
•PAN/GO nanofibers with 5–200 nm pores were fabricated for efficient Cr(VI) removal.•BET specific surface area of the porous nanofibers was 164.2 ± 10.8 m2g−1.•Maximum experimental adsorption ...capacity of Cr(VI) was up to 382.5 ± 6.2 mg/g.•Reusability of the porous nanofibers was at least 20 times cycles.•Simple, low cost, green of one-step electrospinning had great industrial potential.
Development of efficient adsorbent with low cost, simple and green production process, and zero secondary pollution for Cr(VI) removal in industrial applications is a great challenge for modern chemical and materials engineering. Here, we developed a new strategy for preparation of porous polyacrylonitrile (PAN)/graphene oxide (GO) nanofibers by simple one-step electrospinning of PAN/GO solution in N,N-dimethylformamide (DMF)/H2O mixed solvent. The resultant porous PAN/GO nanofibers possessed abundant nanopores (5–200 nm) and thus huge Brunauer-Emmett-Teller (BET) specific surface area (164.2 ± 10.8 m2g−1) and excellent interfacial compatibility. The porous structure maximized the adsorption function of the doped GO nanosheets for Cr(VI) ions, an unprecedented experimental Cr(VI) ions adsorption capacity of 382.5 ± 6.2 mg/g was achieved. And the porous PAN/GO nanofibers also exhibited excellent regeneration, after 20 times adsorption–desorption test, the desorption efficiency of the Cr(VI) ions stably maintained more than 75%. More importantly, compared to the current complex chemical synthesis and material structure design methods of Cr(VI) ions adsorbent, the simple one-step electrospinning fully showed great technical advantages for industrial applications including efficient (100% raw material utilization), green (no any harmful chemical by-products), low cost (only PAN and 1.98 wt% GO). Therefore, we suggested that the porous PAN/GO nanofibers will be a promising candidate in industrial applications as a solid adsorbent for Cr(VI) ions adsorption.
