Piezo-enhanced near infrared photocatalytic nanoheterojunction integrated injectable biopolymer hydrogel for anti-osteosarcoma and osteogenesis combination therapy

Preventing local tumor recurrence while promoting bone tissue regeneration is an urgent need for osteosarcoma treatment. However, the therapeutic efficacy of traditional photosensitizers is limited, and they lack the ability to regenerate bone. Here, a piezo-photo nanoheterostructure is developed based on ultrasmall bismuth/strontium titanate nanocubes (denoted as Bi/SrTiO3), which achieve piezoelectric field-driven fast charge separation coupling with surface plasmon resonance to efficiently generate reactive oxygen species. These hybrid nanotherapeutics are integrated into injectable biopolymer hydrogels, which exhibit outstanding anticancer effects under the combined irradiation of NIR and ultrasound. In vivo studies using patient-derived xenograft models and tibial osteosarcoma models demonstrate that the hydrogels achieve tumor suppression with efficacy rates of 98.6 % and 67.6 % in the respective models. Furthermore, the hydrogel had good filling and retention capabilities in the bone defect region, which exerted bone repair therapeutic efficacy by polarizing and conveying electrical stimuli to the cells under mild ultrasound radiation. This study provides a comprehensive and clinically feasible strategy for the overall treatment and tissue regeneration of osteosarcoma.

Localized Surface Plasmon Resonance-Enhanced Photocatalytic Antibacterial of In-situ Sprayed 0D/2D Heterojunction Composite Hydrogel for Treating Diabetic Wound

Chronic diabetic wounds pose significant challenges due to uncontrolled bacterial infections, prolonged inflammation, and impaired angiogenesis. The rapid advancement of photo-responsive antibacterial therapy showed promise in addressing these complex issues, particularly utilizing 2D heterojunction materials, which offer unique properties. Herein, we designed an in situ sprayed Bi/BiOCl 0D/2D heterojunction composite fibrin gel with the characteristics of rapid formation and effective near-infrared activation for the treatment of non-healing diabetes-infected wounds. The sprayed composite gel can provide protective shielding for skin tissues and promote endothelial cell proliferation, vascularization, and angiogenesis. The Bi/BiOCl 0D/2D heterojunction, with its localized surface plasmon resonance (LSPR), can overcome the wide bandgap limitation of BiOCl, enhancing the generation of local heat and reactive oxygen species under near-infrared irradiation. This facilitated bacterial elimination and reduced inflammation, supporting the accelerated healing of diabetes-infected wounds. Our study underscores the potential of LSPR-enhanced heterojunctions as advanced wound therapies for chronic diabetic wounds. This article is protected by copyright. All rights reserved.

NIR-responsive micropatterned nanocomposite functionalized implant for sequential antibacterial and osteogenesis

The long-term durability of the implant is influenced by two significant clinical challenges, namely bacterial infection and fixation loosening. Conventional implant materials have failed to meet the demands of the dynamic process of infectious bone repair, which necessitates early-stage bacterial sterilization and a conducive environment for late-stage osteogenesis. Consequently, there is an urgent requirement for an implant material that can sequentially regulate antibacterial properties and promote osteogenesis. The study aimed to develop a micropatterned graphene oxide nanocomposite on titanium implant (M-NTO/GO) for the sequential management of bacterial infection and osteogenic promotion. M-NTO/GO exhibited a micropattern nanostructure surface and demonstrated responsiveness to near-infrared (NIR) light. Upon NIR light irradiation, M-NTO/GO exhibited effective antibacterial properties, achieving antibacterial rates of 96.9% and 98.6% against E. coli and S. aureus, respectively. Under no-light condition, the micropatterned topography of M-NTO/GO exhibited the ability to induce directed cell growth, enhance cell adhesion and spreading, and facilitate osteogenic differentiation. These findings suggest the successful development of a functionalized micropatterned nanocomposite implant capable of sequentially regulating antibacterial and osteogenesis activity. Consequently, this highly effective strategy holds promise for expanding the potential applications of orthopedic implants.

Injectable ultrasound-powered bone-adhesive nanocomposite hydrogel for electrically accelerated irregular bone defect healing

The treatment of critical-size bone defects with irregular shapes remains a major challenge in the field of orthopedics. Bone implants with adaptability to complex morphological bone defects, bone-adhesive properties, and potent osteogenic capacity are necessary. Here, a shape-adaptive, highly bone-adhesive, and ultrasound-powered injectable nanocomposite hydrogel is developed via dynamic covalent crosslinking of amine-modified piezoelectric nanoparticles and biopolymer hydrogel networks for electrically accelerated bone healing. Depending on the inorganic-organic interaction between the amino-modified piezoelectric nanoparticles and the bio-adhesive hydrogel network, the bone adhesive strength of the prepared hydrogel exhibited an approximately 3-fold increase. In response to ultrasound radiation, the nanocomposite hydrogel could generate a controllable electrical output (-41.16 to 61.82 mV) to enhance the osteogenic effect in vitro and in vivo significantly. Rat critical-size calvarial defect repair validates accelerated bone healing. In addition, bioinformatics analysis reveals that the ultrasound-responsive nanocomposite hydrogel enhanced the osteogenic differentiation of bone mesenchymal stem cells by increasing calcium ion influx and up-regulating the PI3K/AKT and MEK/ERK signaling pathways. Overall, the present work reveals a novel wireless ultrasound-powered bone-adhesive nanocomposite hydrogel that broadens the therapeutic horizons for irregular bone defects.

Tough, Antifreezing, and Piezoelectric Organohydrogel as a Flexible Wearable Sensor for Human-Machine Interaction

Piezoelectric hydrogel sensors are becoming increasingly popular for wearable sensing applications due to their high sensitivity, self-powered performance, and simple preparation process. However, conventional piezoelectric hydrogels lack antifreezing properties and are thus confronted with the liability of rupture in low temperatures owing to the use of water as the dispersion medium. Herein, a kind of piezoelectric organohydrogel that integrates piezoelectricity, low-temperature tolerance, mechanical robustness, and stable electrical performance is reported by using poly(vinylidene fluoride) (PVDF), acrylonitrile (AN), acrylamide (AAm), p-styrenesulfonate (NaSS), glycerol, and zinc chloride. In detail, the dipolar interaction of the PVDF chain with the PAN chain facilitates the crystal phase transition of PVDF from the α to β phase, which endows the organohydrogels with a high piezoelectric constant d33 of 35 pC/N. In addition, the organohydrogels are highly ductile and can withstand significant tensile and compressive forces through the synergy of the dipolar interaction and amide hydrogen bonding. Besides, by incorporating glycerol and zinc chloride, the growth of ice crystals is inhibited, allowing the organohydrogels to maintain stable flexibility and sensitivity even at -20 °C. The real-time monitoring of the pulse signal for up to 2 min indicates that the gel sensor has stable sensitivity. It is believed that our organohydrogels will have good prospects in future wearable electronics.

Electro-mechanical coupling directs endothelial activities through intracellular calcium ion deployment

Conversion between mechanical and electrical cues is usually considered unidirectional in cells with cardiomyocytes being an exception. Here, we discover a material-induced external electric field (Eex) triggers an electro-mechanical coupling feedback loop in cells other than cardiomyocytes, human umbilical vein endothelial cells (HUVECs), by opening their mechanosensitive Piezo1 channels. When HUVECs are cultured on patterned piezoelectric materials, the materials generate Eex (confined at the cellular scale) to polarize intracellular calcium ions ([Ca2+]i), forming a built-in electric field (Ein) opposing Eex. Furthermore, the [Ca2+]i polarization stimulates HUVECs to shrink their cytoskeletons, activating Piezo1 channels to induce influx of extracellular Ca2+ that gradually increases Ein to balance Eex. Such an electro-mechanical coupling feedback loop directs pre-angiogenic activities such as alignment, elongation, and migration of HUVECs. Activated calcium dynamics during the coupling further modulate the downstream angiogenesis-inducing eNOS/NO pathway. These findings lay a foundation for developing new ways of electrical stimulation-based disease treatment.

All-Polymer Piezoelectric Elastomer with High Stretchability, Low Hysteresis, Self-Adhesion, and UV-Blocking as Flexible Sensor

All-polymer piezoelectric elastomers that integrate self-powered, soft, and elastic performance are attractive in the fields of flexible wearable electronics and human-machine interfaces. However, a lack of adhesion and UV-blocking performances greatly hinders the potential applications of elastomers in these emerging fields. Here, a high-performance piezoelectric elastomer with piezoelectricity, mechanical robustness, self-adhesion, and UV-resistance was developed by using poly(vinylidene fluoride) (PVDF), acrylonitrile (AN), acrylamide (AAm), and oxidized tannic acid (OTA) (named PPO). In this design, the dipole-dipole interactions between the PVDF and PAN chains promoted the content of β-PVDF, endowing high piezoelectric coefficient (d33, 58 pC/N). Besides, high stretchability (∼500%), supercompressibility (∼98%), low Young's modulus (∼0.02 MPa), and remarkable elasticity (∼13.8% hysteresis ratio) were achieved simultaneously for the elastomers. Inspired by the mussel adhesion chemistry, the OTA containing abundant catechol and quinone groups provided high adhesion (93.26 kPa to wood) and an exceptional UV-blocking property (∼99.9%). In addition, the elastomers can produce a reliable electric signal output (Vocmax = 237 mV) and show a fast response (24 ms) when subjected to external force. Furthermore, the elastomer can be easily assembled as a wearable sensor for human physiological (body pulse and speech identification) monitoring and communication.

Flexible, Breathable, and Self-Powered Patch Assembled of Electrospun Polymer Triboelectric Layers and Polypyrrole-Coated Electrode for Infected Chronic Wound Healing

Chronic wound healing is often impaired by bacterial infection and weak trans-epithelial potential. Patches with electrical stimulation and bactericidal activity may solve this problem. However, inconvenient power and resistant antibiotics limit their application. Here, we proposed a self-powered and intrinsic bactericidal patch based on a triboelectric nanogenerator (TENG). Electrospun polymer tribo-layers and a chemical vapor-deposited polypyrrole electrode are assembled as the TENG, offering the patch excellent flexibility, breathability, and wettability. Electrical stimulations by harvesting mechanical motions and positive charges on the polypyrrole surface kill over 96% of bacteria due to their synergistic effects on cell membrane disruption. Moreover, the TENG patch promotes infected diabetic rat skin wounds to heal within 2 weeks. Cell culture and animal tests suggest that electrical stimulation enhances gene expression of growth factors for accelerated wound healing. This work provides new insights into the design of wearable and multifunctional electrotherapy devices for chronic wound treatment.

Piezoelectric Bioactive Glasses Composite Promotes Angiogenesis by the Synergistic Effect of Wireless Electrical Stimulation and Active Ions

Insufficient angiogenesis frequently occurs after the implantation of orthopedic materials, which greatly increases the risk of bone defect reconstruction failure. Therefore, the development of bone implant with improved angiogenic properties is of great importance. Mimicking the extracellular matrix clues provides a more direct and effective strategy to modulate angiogenesis. Herein, inspired by the bioelectrical characteristics of the bone microenvironment, a piezoelectric bioactive glasses composite (P-KNN/BG) based on the incorporation of polarized potassium sodium niobate is constructed, which could effectively promote angiogenesis. It is found that P-KNN/BG has exceptional wireless electrical stimulation performance and sustained active ions release. In vitro cell experiments reveal that P-KNN/BG enhances endothelial cell adhesion, migration, and differentiation via activating the eNOS/NO signaling pathway, which might be contributed to cell membrane hyperpolarization induced by wireless electrical stimulation increase the influx of active ions into the cells. In vivo chick chorioallantoic membrane experiment demonstrates that P-KNN/BG shows excellent pro-angiogenic capacity and biocompatibility. This work broadens the current understanding of bioactive materials with bionic electrical properties, which brings new insights into the clinical treatment of bone defect repair.

Injectable Intrinsic Photothermal Hydrogel Bioadhesive with On-Demand Removability for Wound Closure and MRSA-Infected Wound Healing

Photothermal hydrogel adhesives have yielded promising results for wound closure and infected wound treatment in recent years. However, photothermal hydrogel bioadhesives with on-demand removability without additional nanomaterials-based photothermal agents have rarely been reported in the literature. In this work, an injectable intrinsic photothermal hydrogel bioadhesive with an on-demand removal trait is developed through dynamic cross-linking of gelatin (Gel), tannic acid (TA) quinone, and borax for closing skin incisions and accelerating methicillin-resistant Staphylococcus aureus (MRSA) infected wound healing. The TA quinone containing polyphenol and quinone groups with multifunctional adhesiveness and intrinsic photothermal performance confer the hydrogel adhesive with near-infrared (NIR) responsive antibacterial activity. The cross-linking of pH-sensitive boronic ester (polyphenol-B) and Schiff base bonds endow the hydrogel with great self-healing capacity and on-demand removability. Moreover, the hydrogel possesses good biocompatibility, injectability, and hemostasis. The in vivo experiment in a rat cutaneous incision model and full-thickness MRSA-infected wound model indicate that the smart hydrogel can close wounds efficiently and treat infected ones, demonstrating its superiority in noninvasive treatment of cutaneous incisions and enhancing infected full-thickness wound healing.

Soft, Super-Elastic, All-Polymer Piezoelectric Elastomer for Artificial Electronic Skin

Piezoelectric sensors are widely used in wearable devices to mimic the functions of human skin. However, it is considerably challenging to develop soft piezoelectric materials that can exhibit high sensitivity, stretchability, super elasticity, and suitable modulus. In this study, a soft skin-like piezoelectric polymer elastomer composed of poly(vinylidene fluoride) (PVDF) and a novel elastic substrate polyacrylonitrile is prepared by combining the radical polymerization and freeze-drying processes. Dipole-dipole interaction results in the phase transition of PVDF (α phase to β phase), which enhances the electrical and mechanical performances. Thus, we achieve a high piezoelectric coefficient (d_33max = 63 pC/N), good stretchability (211.3-259.3%), super compressibility (subjected to 99% compression strain without cracking), and super elasticity (100% recovery after extreme compression) simultaneously for the elastomer. The soft composite elastomer produces excellent electrical signal output (V_ocmax = 253 mV) and responds rapidly (15 ms) to stress-induced polarization effects. In addition, the elastomer-based sensor accurately detects various physiological signals such as gestures, throat vibrations, and pulse waves. The developed elastomers exhibit excellent mechanical properties and high sensitivity, which helps facilitate their application as artificial electronic skin to sense subtle external pressure in real time.

Light-Programmable Nanocomposite Hydrogel for State-Switchable Wound Healing Promotion and Bacterial Infection Elimination

Developing an ideal wound dressing that not only accelerates wound healing but also eliminates potential bacterial infections remains a difficult balancing act. This work reports the design of a light-programmable sodium alginate nanocomposite hydrogel loaded with BiOCl/polypyrrole (BOC/PPy) nanosheets for state-switchable wound healing promotion and bacterial infection elimination remotely. The nanocomposite hydrogel possesses programmable photoelectric or photothermal conversion due to the expanded light absorption range, optimized electron transmission interface, promoted photo-generated charge separation, and transfer of the BOC/PPy nanosheets. Under white light irradiation state, the nanocomposite hydrogel induces human umbilical vein endothelial cells migration and angiogenesis, and accelerates the healing efficiency of mouse skin in vivo. Under near-infrared light irradiation state, the nanocomposite hydrogel presents superior antibacterial capability in vitro, and reaches an antibacterial rate of 99.1% for Staphylococcus aureus infected skin wound in vivo. This light-programmable nanocomposite hydrogel provides an on-demand resolution of biological state-switching to balance wound healing and elimination of bacterial infection.

One-Dimensional Ferroelectric Nanoarrays with Wireless Switchable Static and Dynamic Electrical Stimulation for Selective Regulating Osteogenesis and Antiosteosarcoma

Preventing local tumor recurrence and simultaneously improving bone-tissue regeneration are in great demand for osteosarcoma therapy. However, the current therapeutic implants fail to selectively suppress tumor growth and enhance osteogenesis, and antitumor therapy may compromise osseointegration of the bone implant. Here, based on the different responses of bone tumor cells and osteoblasts to different electric stimulations, we constructed ferroelectric BaTiO₃ nanorod arrays (NBTO) on the surface of titanium implants with switchable dynamic and static electrical stimulation for selective bone-tumor therapy and bone tissue regeneration. Polarized NBTO (PNBTO) generated a sustained dynamic electrical stimulus in response to wireless ultrasonic irradiation ("switch-on"), which disrupted the orientation of the spindle filaments of the tumor cell, blocked the G2/M phase of mitosis, and ultimately led to tumor cell death, whereas it had almost no cytotoxic effect on normal bone cells. Under the switch-off state, PNBTO with a high surface potential provided static electrical stimulation, accelerating osteogenic differentiation of mesenchymal stem cells and enhancing the quality of bone regeneration both in vitro and in vivo. This study broadens the biomedical potential of electrical stimulation therapy and provides a comprehensive and clinically feasible strategy for the overall treatment and tissue regeneration in osteosarcoma.

Strong Biopolymer-Based Nanocomposite Hydrogel Adhesives with Removability and Reusability for Damaged Tissue Closure and Healing

Bioadhesives are widely used in a variety of medical settings due to their ease of use and efficient wound closure and repair. However, achieving both strong adhesion and removability/reusability is highly needed but challenging. Here, we reported an injectable mesoporous bioactive glass nanoparticle (MBGN)-incorporated biopolymer hydrogel bioadhesive that demonstrates a strong adhesion strength (up to 107.55 kPa) at physiological temperatures that is also removable and reusable. The incorporation of MBGNs in the biopolymer hydrogel significantly enhances the tissue adhesive strength due to an increased cohesive and adhesive property compared to the hydrogel adhesive alone. The detachment of bioadhesive results from temperature-induced weakening of interfacial adhesive strength. Moreover, the bioadhesive displays injectability, self-healing, and excellent biocompatibility. We demonstrate potential applications of the bioadhesive in vitro, ex vivo, and in vivo for hemostasis and intestinal leakage closure and accelerated skin wound healing compared to surgical wound closures. This work provides a novel design of strong and removable bioadhesives.

Wireless electrical stimulation at the nanoscale interface induces tumor vascular normalization

Pathological angiogenesis frequently occurs in tumor tissue, limiting the efficiency of chemotherapeutic drug delivery and accelerating tumor progression. However, traditional vascular normalization strategies are not fully effective and limited by the development of resistance. Herein, inspired by the intervention of endogenous bioelectricity in vessel formation, we propose a wireless electrical stimulation therapeutic strategy, capable of breaking bioelectric homeostasis within cells, to achieve tumor vascular normalization. Polarized barium titanate nanoparticles with high mechano-electrical conversion performance were developed, which could generate pulsed open-circuit voltage under low-intensity pulsed ultrasound. We demonstrated that wireless electrical stimulation significantly inhibited endothelial cell migration and differentiation in vitro. Interestingly, we found that the angiogenesis-related eNOS/NO pathway was inhibited, which could be attributed to the destruction of the intracellular calcium ion gradient by wireless electrical stimulation. In vivo tumor-bearing mouse model indicated that wireless electrical stimulation normalized tumor vasculature by optimizing vascular structure, enhancing blood perfusion, reducing vascular leakage, and restoring local oxygenation. Ultimately, the anti-tumor efficacy of combination treatment was 1.8 times that of the single chemotherapeutic drug doxorubicin group. This work provides a wireless electrical stimulation strategy based on the mechano-electrical conversion performance of piezoelectric nanoparticles, which is expected to achieve safe and effective clinical adjuvant treatment of malignant tumors.

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Wireless electrical stimulation was proposed for tumor vascular normalization.

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Polarized ferroelectric nanoparticles were developed for wireless stimulation.

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Wireless stimulation inhibited endothelial cell migration and differentiation.

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The intracellular Ca²⁺ gradient and eNOS/NO pathway of cells were disturbed.

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In vivo vascular normalization and anti-tumor efficacy were significantly enhanced.

Janus electro-microenvironment membrane with surface-selective osteogenesis/gingival healing ability for guided bone regeneration

Guided bone regeneration is widely applied in clinical practice to treat alveolar bone defects. However, the rate of healing of severe alveolar bone defects is slow, and there is a high incidence of soft tissue wound dehiscence. In this study, we propose a barrier membrane with a Janus electro-microenvironment (JEM) to achieve side-selective bone regeneration and soft tissue healing. The JEM membrane was constructed using a polarized polyvinylidene fluoride ferroelectric membrane with different surface potentials on either side. It promoted osteogenic differentiation and bone regeneration on the negatively polarized side (JEM-) and soft tissue regeneration on the positively polarized side (JEM+). Further investigation revealed that the JEM-mediated promotion of bone formation was related to mitochondrial autophagy, as indicated by depolarization of the mitochondrial membrane potential and the expression of LC3, Pink I, and Parkin. Moreover, the gingival healing promoted by JEM+ was related to oxidative phosphorylation in mitochondria, as indicated by the upregulation of mitochondrial complexes I–V and an increase in ATP generation. The design concept of the JEM provides a new avenue for regulating tissue regeneration between different tissue interfaces.

Internal Wireless Electrical Stimulation from Piezoelectric Barium Titanate Nanoparticles as a New Strategy for the Treatment of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is an aggressive BC subtype with a higher metastatic rate and a worse 5-year survival ratio than the other BC. It is an urgent need to develop a noninvasive treatment with high efficiency to resist TNBC cell proliferation and invasion. Internal wireless electric stimulation (ES) based on piezoelectric materials is an emerging noninvasive strategy, with adjustable ES intensity and excellent biosafety. In this study, three different barium titanate nanoparticles (BTNPs) with different crystal phases and piezoelectric properties were studied. Varying intensities of internal ES were generated from the three BTNPs (i.e., BTO, U-BTO, P-BTO). In vitro tests revealed that the internal ES from BTNPs was efficient at reducing the proliferative potential of cancer cells, particularly BC cells. In vitro experiments on MDA-MB-231, a typical TNBC cell line, further revealed that the internal wireless ES from BTNPs significantly inhibited cell growth and migration up to about 82% and 60%, respectively. In vivo evaluation of MDA-MB-231 tumor-bearing mice indicated that internal ES not only resisted almost 70% tumor growth but also significantly inhibited lung metastasis. More importantly, in vitro and in vivo studies demonstrated a favorable correlation between the anticancer impact and the intensities of ES. The underlying mechanism of MDA-MB-231 cell proliferation and metastasis inhibition caused by internal ES was also investigated. In summary, our results revealed the effect and mechanism of internal ES from piezoelectric nanoparticles on TNBC cell proliferation and migration regulation and proposed a promising noninvasive therapeutic strategy for TNBC with minimal side effects while exhibiting good therapeutic efficiency.

Plasmon-Enhanced Electrocatalysis of Conductive Polymer-Based Nano-Heterojunction for Small Molecule Metabolites Diagnostics

Conductive polymers are promising electrode candidates in the nonenzymatic catalytic detection of small molecule metabolites, due to the tunable electronic conductivity and versatile modifiability. However, the complex catalytic reaction pathway of conductive polymers results in lower detection sensitivity and a narrower linear range compared with clinical metal-based and carbon-based electrodes. Localized surface plasmon resonance (LSPR), characterized by deep strong light-matter coupling, has great potential in driving surface catalytic reactions at an ultrafast rate. Here, we constructed a salix argyracea-like polypyrrole nanowires/silver nanoparticles (PPy/AgNPs) heterojunction electrode using polydopamine as a dopant and chelator. Through cyclic voltammetry, the Mott-Schottky curve, and COMSOL simulation, we demonstrated that the LSPR-excited photocarriers enhanced PPy/AgNPs electrode electrocatalysis. Thus, the detection current response and linear range were significantly improved under the LSPR excitation when taking glucose and hydrogen peroxide as models of small molecule metabolites. Furthermore, we discussed the LSPR-enhanced detection mechanism of PPy/AgNPs electrode from the aspects of the Tafel slope, the apparent electron diffusion coefficient, and the charge transfer resistance. This strategy opens a new avenue toward the design of LSPR-enhanced conductive polymer electrodes.

Space-Confined Synthesis of Thin Polypyrrole Nanosheets in Layered Bismuth Oxychloride for a Photoresponse Antibacterial within the Near-Infrared Window and Accelerated Wound Healing

Bacterial infection greatly affects the rate of wound healing. Both photothermal and photodynamic antibacterial therapies activated by near-infrared (NIR) light with semiconductor nanomedicine are two effective approaches to address bacterial infections, but they cannot coexist synergistically to kill bacteria more efficiently because of the limitation of the band structure. Here, inspired by the natural core-shell structure and photosynthesis simultaneously, polypyrrole (PPy) is synthesized in the two-dimensional restricted area of the layered bismuth oxychloride (BiOCl) nanosheets through the in situ ultrasonic recombination method. The atomic-level interface contact and bonding formed in the PPy-BiOCl intercalated nanosheets not only improve the light-to-heat conversion capabilities of PPy but also promote the transmission of PPy photogenerated charge carriers to the BiOCl semiconductor. The nanocomposites take advantage of the deeper tissue penetration under NIR light irradiation and exhibit excellent photothermal and photodynamic synergistic antibacterial activity. In addition, PPy-BiOCl intercalated nanosheets have good biocompatibility and accelerate wound healing through their antimicrobial activity and skin repair function. The space-confined synthesis of thin PPy nanosheets in layered structures offers an efficient NIR photoresponsive nanomedicine for the treatment of pathogen infection, with promising applications in infected wound healing.

Piezoelectric Hydrogel for Prophylaxis and Early Treatment of Pressure Injuries/Pressure Ulcers

Pressure injuries/pressure ulcers (PIs/PUs) are a critical global healthcare issue and represent a considerable burden on healthcare resources. Prevention of PIs/PUs is the least costly approach and minimizes the patient suffering compared with treatment. Besides, sustained tissue load alleviation and microenvironment management are the most crucial properties for dressings in PI/PU prevention. Hydrogel dressings have attracted a lot of attention to prevent PIs/PUs because of their unique mechanical properties and ability to manage the microenvironment of skin. However, auxiliary prophylaxis and early treatment of PIs/PUs remain a challenge and an acute clinical demand. Here, we report on an electroactive hydrogel with large stretchability (∼380%) and skinlike ductility, and Young's modulus (0.48 ± 0.03 MPa) matches that of human skin (0.5-1.95 MPa). The hydrogel displayed piezoelectric properties and mechanical-electric response stability and sensitivity. Our results indicated that the hydrogel was able to promote in vitro angiogenesis under piezoelectric stimulation and exhibited biocompatibility, which has the potential for forming fine vessels at the damaged sites of PIs/PUs. Furthermore, finite element analysis and pressure dispersion experiments demonstrated that the hydrogel was suitable for preventing PIs/PUs by redistributing force, reducing tissue distortion, and maintaining the microenvironment for skin. This work offers a new strategy for designing and evaluating the dressing for prophylaxis and the early treatment of PIs/PUs.

In Situ Construction of Black Titanium Oxide with a Multilevel Structure on a Titanium Alloy for Photothermal Antibacterial Therapy

Postsurgical infection of orthopedic fixation materials is considered to be the main cause of fixation failure. To address the problem, clinical treatment often relies on long-term antibiotics, secondary surgery, and so forth, which cause pain and suffering to patients. Constructing a light-responsive surface structure on the implant has attracted widespread attention for the management of postsurgical infections because of its noninvasiveness and controllability. Nevertheless, the application of light-responsive structures on implants is still limited by their unsafety and instability. In this work, a black titanium oxide layer with a multilevel structure and lattice defects was in situ constructed on a titanium alloy through pulsed laser ablation treatment. Under the synergistic effect of the multilevel structure and crystal defects, the surface of the titanium alloy exhibited good near-infrared light-responsive photothermal ability. The black titanium oxide multilevel structure reached high antibacterial efficiencies of about 99.37 and 99.29% against Staphylococcus aureus and Escherichia coli under 10 min near-infrared light irradiation. Furthermore, the black titanium oxide layer possessed similar biocompatibility compared with the titanium alloy. This near-infrared light-responsive photothermal therapy based on the construction of a multilevel structure and introduction of lattice defects provides an effective strategy for clinical postsurgical infections of orthopedic fixation.

Tough and Highly Efficient Underwater Self-Repairing Hydrogels for Soft Electronics

The vulnerability of hydrogel electronic materials to mechanical damage due to their soft nature has necessitated the development of self-repairing hydrogel electronics. However, the development of such material with underwater self-repairing capability as well as excellent mechanical properties for application in aquatic environments is highly challenging and has not yet been fully realized. This study designs a tough and highly efficient underwater self-repairing supramolecular hydrogel by synergistically combining weak hydrogen bonds (H-bonds) and strong dipole-dipole interactions. The resultant hydrogel has high stretchability (up to 700%) and toughness (4.45 MJ m^-3 ), and an almost 100% fast strain self-recovery (10 min). The underwater healing process is rapid and autonomous (98% self-repair efficiency after 1 h of healing). Supramolecular hydrogels can be developed as soft electronic sensors for physiological signal detection (gestures, breathing, microexpression, and vocalization) and real-time underwater communication (Morse code). Importantly, the hydrogel sensor can function underwater after mechanical damage because of its highly efficient underwater self-repairing capability.

Exosomes-Loaded Electroconductive Hydrogel Synergistically Promotes Tissue Repair after Spinal Cord Injury via Immunoregulation and Enhancement of Myelinated Axon Growth

Electroconductive hydrogels are very attractive candidates for accelerated spinal cord injury (SCI) repair because they match the electrical and mechanical properties of neural tissue. However, electroconductive hydrogel implantation can potentially aggravate inflammation, and hinder its repair efficacy. Bone marrow stem cell-derived exosomes (BMSC-exosomes) have shown immunomodulatory and tissue regeneration effects, therefore, neural tissue-like electroconductive hydrogels loaded with BMSC-exosomes are developed for the synergistic treatment of SCI. These exosomes-loaded electroconductive hydrogels modulate microglial M2 polarization via the NF-κB pathway, and synergistically enhance neuronal and oligodendrocyte differentiation of neural stem cells (NSCs) while inhibiting astrocyte differentiation, and also increase axon outgrowth via the PTEN/PI3K/AKT/mTOR pathway. Furthermore, exosomes combined electroconductive hydrogels significantly decrease the number of CD68-positive microglia, enhance local NSCs recruitment, and promote neuronal and axonal regeneration, resulting in significant functional recovery at the early stage in an SCI mouse model. Hence, the findings of this study demonstrate that the combination of electroconductive hydrogels and BMSC-exosomes is a promising therapeutic strategy for SCI repair.

An injectable, self-healing, electroconductive extracellular matrix-based hydrogel for enhancing tissue repair after traumatic spinal cord injury

Injectable biomaterial-based treatment is a promising strategy to enhance tissue repair after traumatic spinal cord injury (SCI) by bridging cavity spaces. However, there are limited reports of injectable, electroconductive hydrogels with self-healing properties being employed for the treatment of traumatic SCI. Hence, a natural extracellular matrix (ECM) biopolymer (chondroitin sulphate and gelatin)-based hydrogel containing polypyrrole, which imparted electroconductive properties, is developed for traumatic SCI repair. The resulting hydrogels showed mechanical (~928 Pa) and conductive properties (4.49 mS/cm) similar to natural spinal cord tissues. Moreover, the hydrogels exhibited shear-thinning and self-healing abilities, which allows it to be effectively injected into the injury site and to fill the lesion cavity to accelerate the tissue repair of traumatic SCI. In vitro, electroconductive ECM hydrogels promoted neuronal differentiation, enhanced axon outgrowth, and inhibited astrocyte differentiation. The electroconductive ECM hydrogel activated endogenous neural stem cell neurogenesis in vivo (n = 6), and induced myelinated axon regeneration into the lesion site via activation of the PI3K/AKT and MEK/ERK pathways, thereby achieving significant locomotor function restoration in rats with spinal cord injury (p < 0.001, compared to SCI group). Overall, the injectable self-healing electroconductive ECM-based hydrogels developed in this study are ideal biomaterials for treatment of traumatic SCI.

Extracellular Matrix-Based Conductive Interpenetrating Network Hydrogels with Enhanced Neurovascular Regeneration Properties for Diabetic Wounds Repair

The critical effects that impair diabetic wound healing are characterized by poor vascularization and severe peripheral neuropathy. Current management strategies for diabetic wound healing are unsatisfactory, due to the paucity of neurovascular regeneration at the wound site. Importantly, conductivity in skin tissue is reported to be essential for modulating myriad biological processes especially vascular and nerve regeneration. Herein, an extracellular matrix (ECM)-based conductive dressing is synthesized from an interpenetrating polymer network hydrogel composed of gelatin methacryloyl, oxidized chondroitin sulfate (OCS), and OCS-polypyrrole conductive nanoparticles that can promote diabetic wound repairing by enhancing local neurovascular regeneration. The conductive hydrogels combine the advantageous features of water-swollen hydrogels with conductive polymers (CPs) to provide tissue-matching electrical conductivity and mechanical properties for neurovascular regeneration. In vitro and in vivo studies show that the conductive hydrogel can promote neurovascular regeneration by increasing intracellular Ca²⁺ concentration, which subsequently promotes phosphorylation of proteins in the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) and mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) pathways. Furthermore, the conductive hydrogel stimulates full-thickness diabetic wound repair on day 14 by promoting local neurovascular regeneration and collagen deposition. These findings corroborate that the ECM-based conductive interpenetrating network hydrogel dressing significantly promotes wound repairing due to its neurovascular regeneration properties, suggesting that they are suitable candidates for diabetic wound repair.

[Characteristics of genotype of monogenic nephrolithiasis in Chinese pediatric patients with nephrolithiasis]

Objective: To analyze the genotype characteristics of children with monogenic nephrolithiasis. Methods: The clinical data and genetic test results of 56 children with monogenic nephrolithiasis diagnosed and treated in Beijing Friendship Hospital, Capital Medical University from January 2016 to December 2020 were analyzed retrospectively. All pediatric patients were diagnosed by whole exome sequencing, and the genotype characteristics of the children were analyzed. Results: Among 56 children with monogenic nephrolithiasis, there were 39 males and 17 females, with an average age of 4 years (range, 5 months to 14 years). A total of 11 genes were found to have mutations, including 7 autosomal recessive genes, 1 X-linked recessive gene, and 3 genes with both recessive and dominant, of which HOGA1 gene mutation was the most common (16 cases, 28.6%), followed by AGXT gene (15 cases, 26.8%), SLC3A1 gene (6 cases, 10.7%), SLC7A9 gene (5 cases, 8.9%) and GRHPR gene (5 cases, 8.9%). The mutation types included nonsense mutations, frameshift mutations and splicing mutations, with 14 novel mutations. Genes such as AGXT, GRHPR and HOGA1 have hotspot mutations or hotspot mutation regions, which are c. 815-816 insGA and c. 33dupC mutation, c.864-865delTG mutation and c. 834-834+1 mutation region; SLC3A1 and SLC7A9 genes had 9 novel mutations, but no hotspot mutation or hotspot regions were found. Conclusion: Monogenic nephrolithiasis is rare and mostly autosomal recessive in Chinese children, with mutations in the causative genes HOGA1, AGXT, SLC3A1,SLC7A9 and GRHPR. AGXT, GRHPR and HOGA1 genes have hotspot mutations or hotspot mutation regions, and mutations may have ethnic differences.

One-step construction of a food-grade expression system based on the URA3 gene in Kluyveromyces lactis

Proteins from food-grade expression systems can be used in food products and medical applications. Herein, we describe a one-step method of constructing an expression vector in Kluyveromyces lactis by combining a URA3-deficient strain and a plasmid vector with no drug-resistant selection. Adjacent DNA elements of the vector were assembled in a targeted manner through a reaction with a special recombinase to form a plasmid vector using a one-step reaction. The unnecessary fragments containing the pUC origin and the ampicillin resistance gene were removed, and the vector was isolated and purified before transformation. A single transformation of the vector can produce a URA3-deficient strain. PCR assay, sequencing, and western blot analysis all indicated that the method of vector construction and target protein expression (mCherry and human serum albumin) were successful. This method may potentially be applied to any species containing the URA3 gene; this system has the potential to become a safe and powerful tool for promoting protein expression in food-safe species.

Self-curling electroconductive nerve dressing for enhancing peripheral nerve regeneration in diabetic rats

Conductive scaffolds have been shown to exert a therapeutic effect on patients suffering from peripheral nerve injuries (PNIs). However, conventional conductive conduits are made of rigid structures and have limited applications for impaired diabetic patients due to their mechanical mismatch with neural tissues and poor plasticity. We propose the development of biocompatible electroconductive hydrogels (ECHs) that are identical to a surgical dressing in this study. Based on excellent adhesive and self-healing properties, the thin film-like dressing can be easily attached to the injured nerve fibers, automatically warps a tubular structure without requiring any invasive techniques. The ECH offers an intimate and stable electrical bridge coupling with the electrogenic nerve tissues. The in vitro experiments indicated that the ECH promoted the migration and adhesion of the Schwann cells. Furthermore, the ECH facilitated axonal regeneration and remyelination in vitro and in vivo through the MEK/ERK pathway, thus preventing muscle denervation atrophy while retaining functional recovery. The results of this study are likely to facilitate the development of non-invasive treatment techniques for PNIs in diabetic patients utilizing electroconductive hydrogels.

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Conventional conductive conduits are made of rigid structures and have limited applications for diabetic patients.

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Self-curling electroconductive hydrogel with porous, highly conductive, and adhesive properties were identical to a surgical dressing.

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Electroconductive hydrogel facilitates axonal regeneration and remyelination via MEK/ERK pathway.

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ECH dressing prevent muscle denervation atrophy and retain functional recovery in diabetic rats.

Biomimetic Ti-6Al-4V alloy/gelatin methacrylate hybrid scaffold with enhanced osteogenic and angiogenic capabilities for large bone defect restoration

Titanium-based scaffolds are widely used implant materials for bone defect treatment. However, the unmatched biomechanics and poor bioactivities of conventional titanium-based implants usually lead to insufficient bone integration. To tackle these challenges, it is critical to develop novel titanium-based scaffolds that meet the bioadaptive requirements for load-bearing critical bone defects. Herein, inspired by the microstructure and mechanical properties of natural bone tissue, we developed a Ti–6Al–4V alloy (TC4)/gelatin methacrylate (GelMA) hybrid scaffold with dual bionic features (GMPT) for bone defect repair. GMPT is composed of a hard 3D-printed porous TC4 metal scaffold (PT) backbone, which mimics the microstructure and mechanical properties of natural cancellous bone, and a soft GelMA hydrogel matrix infiltrated into the pores of PT that mimics the microenvironment of the extracellular matrix. Ascribed to the unique dual bionic design, the resultant GMPT demonstrates better osteogenic and angiogenic capabilities than PT, as confirmed by the in vitro and rabbit radius bone defect experimental results. Moreover, controlling the concentration of GelMA (10%) in GMPT can further improve the osteogenesis and angiogenesis of GMPT. The fundamental mechanisms were revealed by RNA-Seq analysis, which showed that the concentration of GelMA significantly influenced the expression of osteogenesis- and angiogenesis-related genes via the Pi3K/Akt/mTOR pathway. The results of this work indicate that our dual bionic implant design represents a promising strategy for the restoration of large bone defects.

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A novel TC4/GelMA hybrid scaffold (GMPT) was designed to mimic natural bone microstructure and mechanical property.

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The GMPT with 10 wt% of GelMA showed best capability for promoting osteogenesis and angiogenesis.

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A bioactive soft surface with suitable stiffness can activate focal adhesion pathway and the downstream PI3K/AKT pathway.

Exosome-functionalized polyetheretherketone-based implant with immunomodulatory property for enhancing osseointegration

The host immune response effecting on biomaterials is critical to determine implant fates and bone regeneration property. Bone marrow stem cells (BMSCs) derived exosomes (Exos) contain multiple biosignal molecules and have been demonstrated to exhibit immunomodulatory functions. Herein, we develop a BMSC-derived Exos-functionalized implant to accelerate bone integration by immunoregulation. BMSC-derived Exos were reversibly incorporated on tannic acid (TA) modified sulfonated polyetheretherketone (SPEEK) via the strong interaction of TA with biomacromolecules. The slowly released Exos from SPEEK can be phagocytosed by co-cultured cells, which could efficiently improve the biocompatibilities of SPEEK. In vitro results showed the Exos loaded SPEEK promoted macrophage M2 polarization via the NF-κB pathway to enhance BMSCs osteogenic differentiation. Further in vivo rat air-pouch model and rat femoral drilling model assessment of Exos loaded SPEEK revealed efficient macrophage M2 polarization, desirable new bone formation, and satisfactory osseointegration. Thus, BMSC-derived Exos-functionalized implant exerted osteoimmunomodulation effect to promote osteogenesis.

Spiral Donor Design Strategy for Blue Thermally Activated Delayed Fluorescence Emitters

Thermally activated delayed fluorescence (TADF) emitters with a spiral donor show tremendous potential toward high-level efficient blue organic light-emitting diodes (OLEDs). However, the underlying design strategy of the spiral donor used for blue TADF emitters remains unclear. As a consequence, researchers often do "try and error" work in the development of new functional spiral donor fragments, making it slow and inefficient. Herein, we demonstrate that the energy level relationships between the spiral donor and the luminophore lead to a significant effect on the photoluminescent quantum yields (PLQYs) of the target materials. In addition, a method involving quantum chemistry simulations that can accurately predict the aforementioned energy level relationships by simulating the spin density distributions of the triplet excited states of the spiral donor and corresponding TADF emitters and the triplet excited natural transition orbitals of the TADF emitters is established. Moreover, it also revealed that the steric hindrance in this series of molecules can form a nearly unchanged singlet (S₁) state geometry, leading to a reduced nonradiative decay and high PLQY, while a moderated donor-acceptor (D-A) torsion in the triplet (T₁) state can induce a strong vibronic coupling between the charge-transfer triplet (³CT) state and the local triplet (³LE) state, achieving an effective reverse intersystem crossing (RISC) process. Furthermore, an electric-magnetic coupling is formed between the high-lying ³LE state and the charge-transfer singlet (¹CT) state, which may open another RISC channel. Remarkably, in company with the optimized molecular structure and energy alignment, the pivotal TADF emitter DspiroS-TRZ achieved 99.9% PLQY, an external quantum efficiency (EQE) of 38.4%, which is the highest among all blue TADF emitters reported to date.

Differences in hypertension and prehypertension among people living with and without HIV in China: role of HIV infection and antiretroviral therapy

OBJECTIVES

Hypertension is a growing health concern in people living with HIV (PLWH). However, association between HIV infection and hypertension is equivocal.

METHODS

In all, 1472 PLWH and 2944 HIV-negative individuals frequency-matched by age and sex were derived from the baseline survey of Comparative HIV and Aging Research in Taizhou (CHART), China. Prehypertension was defined as systolic blood pressure (BP) of 120-139 mmHg and/or diastolic blood pressure of 80-89 mmHg.

RESULTS

Despite the fact that prevalence of hypertension was overall lower among PLWH than among HIV-negative people (21.1% vs. 29.1%, P < 0.001), it was similar at ages 18-29 (7.6% vs. 8.5%) and 30-44 years (17.1% vs. 18.5%) but significantly lower in PLWH at ages 45-59 (26.1% vs. 40.7%) and 60-75 years (37.1% vs. 57.3%). Prehypertension prevalence was consistently higher in PLWH across all age groups. In the model adjusting for traditional risk factors, HIV infection was associated with hypertension (adjusted odds ratio [aOR] = 1.27, 95% confidence interval: 1.04-1.55) and prehypertension (aOR = 1.77, 95% CI: 1.51-2.08), and attenuated after additional adjustment for abdominal obesity. Age-stratified analysis showed that these associations of HIV with hypertension were observed at ages 18-29 and 30-44 years and associations with prehypertension were observed at ages 18-29, 30-44 and 45-59 years only. Years since HIV diagnosis and stavudine use were the HIV-specific factors independently associated with hypertension or/and prehypertension.

CONCLUSIONS

HIV infection is independently associated with prehypertension and hypertension especially at younger ages, and this risk may increase as treatment becomes prolonged. Our findings reinforce the urgent necessity for active BP screening and control strategies be adopted for PLWH in China.

Wireless Electrochemotherapy by Selenium-Doped Piezoelectric Biomaterials to Enhance Cancer Cell Apoptosis

Cancer residues around the surgical site remain a significant cause of treatment failure with cancer recurrence. To prevent cancer recurrence and simultaneously repair surgery-caused defects, it is urgent to develop implantable biomaterials with anticancer ability and good biological activity. In this work, a functionalized implant is successfully fabricated by doping the effective anticancer element selenium (Se) into the potassium-sodium niobate piezoceramic, which realizes the wireless combination of electrotherapy and chemotherapy. Herein, we demonstrate that the Se-doped piezoelectric implant can cause mitochondrial damage by increasing intracellular reactive oxygen species levels and then trigger the caspase-3 pathway to significantly promote apoptosis of osteosarcoma cells in vitro. Meanwhile, its good biocompatibility has been verified. These results are of great importance for future deployment of wireless electro- and chemostimulation to modulate biological process around the defective tissue.

Ultrafast and On-Demand Oil/Water Separation Membrane System Based on Conducting Polymer Nanotip Arrays

Ultrafast oil/water separation based on tunable superwettability switch remains a big challenge. Here, inspired by the ultrafast water transport mechanism in sarracenia, we develop a micro/nanostructured porous membrane with conducting polymer nanotip arrays through the surface-initiated polymerizations. By modulating the height (ranging from 49-529 nm) and redox states of nanotips, a smart reversible superwettability switch is facile to obtain with contact angles of water/oil arranging from 161° to about 0°. Besides, liquid transport speed was accelerated more than 1.5 times by increasing the nanotip length. The water flux could reach up to 50326 L m^-2 h^-1 (1000 times that of a typical industrial ultrafiltration membrane). This is attributed to the stable and continuous water film along the nanotips, which provide a lubrication layer, leading to an increase of permeability. This work provides significant insights into macro/nanostructured membrane design for smart separation, blood lipid filtration, and smart nanoreactors with high permeability.

J-Aggregation Enhances the Electroluminescence Performance of a Sky-Blue Thermally Activated Delayed-Fluorescence Emitter in Nondoped Organic Light-Emitting Diodes

A pivotal thermally activated delayed-fluorescence (TADF) emitter, DspiroAc-TRZ, was developed, and it exhibits greatly enhanced electroluminescence performance in nondoped organic light-emitting diodes (OLEDs) owing to the concurrent manipulation of aggregation behavior and monomolecular structure. The delicate non-planar packing pattern in the DspiroAc-TRZ crystal can not only lead to highly efficient solid-state luminescence but also form a loose intermolecular packing pattern, greatly decreasing the HOMO or LUMO overlaps in dimers and shortening the triplet exciton diffusion length. In addition, the rigid donor and acceptor moieties in DspiroAc-TRZ can rigidify the molecular backbone, resulting in a tiny geometric vibrational relaxation in the excited state. Impressively, high photoluminescent quantum yields of 78.5 and 83.7% were achieved for the DspiroAc-TRZ single crystal and nondoped film. A high external quantum efficiency (EQE) of 25.7% was achieved in a nondoped sky-blue TADF OLED, which is higher than any reported EQE value of nondoped sky-blue TADF OLEDs so far.

Latest research progress of marine microbiological corrosion and bio-fouling, and new approaches of marine anti-corrosion and anti-fouling

Marine resources and industry have become one of the most important pillars in economic development all over the world. However, corrosion of materials is always the most serious problem to the infrastructure and equipment served in marine environment. Researchers have found that microbiologically influenced corrosion (MIC) and marine bio-fouling are two main mechanisms of marine corrosions due to the complicated marine environment and marine organisms. This article summarized the latest research progress about these two mechanisms and indicated that both MIC and marine bio-fouling are closely related to the biofilms on material surfaces formed by the marine microorganisms and their metabolites. As a result, to prevent the occurrence of MIC and bio-fouling, it is important to control the microorganisms in biofilms or prevent the adhesion and formation of biofilms. The traditional method of using chemical bactericide or antifoulant faces the problems of pollution and microorganism resistance. This article introduced four research approaches about the new tendency of applying new materials and technologies to cooperate with traditional chemicals to achieve better and longer effects with lower environment pollution through synergistic actions. Finally, some future research tendencies were proposed for whole marine anti-corrosion and anti-fouling areas.

Inhibition of astrocytic differentiation of transplanted neural stem cells by chondroitin sulfate methacrylate hydrogels for the repair of injured spinal cord

Neural stem cell (NSC) transplantation exerts a therapeutic effect on spinal cord injury (SCI) but is limited to an unregulated differentiation pattern by which NSCs preferentially differentiate into astrocytes, with relatively few neurons. It is well established that the increased NSC-derived astrocytes exhibit aberrant axonal sprouting associated with allodynia-like symptoms of the forepaws. Some strategies have been used to overcome this issue, such as regulation of major pathways, ex vivo gene transfer, and genetic overexpression. However, lack of efficiency, viral vector safety issues and the risk of tumorigenesis have hindered the clinical application of these treatments. Here, we show that astrocytic differentiation of NSCs in vitro and in vivo can be inhibited by encapsulation of cells in a three-dimensional chondroitin sulfate methacrylate (CSMA) hydrogel. When CSMA hydrogels were used to transplant NSCs, the combinatory implant promoted functional recovery and attenuated the hypersensitivity responses of the forepaws. Further analysis showed that transplantation of NSCs within CSMA hydrogels reduced injured cavity areas and promoted neurogenesis rather than fibroglial formation after graft implantation. Furthermore, the treatment prevented allodynia-related CGRP/GAP43-positive nociception due to fibers sprouting into inappropriate lamina regions. Taken together, these findings show that CSMA/NSCs combined transplantation helps prevent adverse side effects of NSCs treatment and promotes recovery of SCI.

Polypyrrole Nanocones and Dynamic Piezoelectric Stimulation-Induced Stem Cell Osteogenic Differentiation

Imitating the physiological microenvironment of living cell and tissues opens new avenues of research into the application of electricity to medical therapies. In this study, dynamic piezoelectric stimulation is generated in a dynamic culture because of the piezoelectric effect of the poly(vinylidene fluoride)-polypyrrole (PVDF-PPy) electroactive composite. Combined with PPy nanocones, dynamic piezoelectric signals are effectively and continuously provided to cells. In the presence of dynamic piezoelectric stimulation and PPy nanocones, PPy-PVDF NS samples show promoted bone mesenchymal stem cell (BMSCs) adhesion, spreadin, and osteogenic differentiation. On the basis of the results of this study, PPy nanocones and dynamic piezoelectric stimulation can be administered to modulate cell behavior, paving the way for the exploration of cellular responses to dynamic electrical stimulation.

A spatially varying charge model for regulating site-selective protein adsorption and cell behaviors

Implanted materials that enter the body first interact with proteins in body fluids, and cells then perceive and respond to the foreign implant through this layer of adsorbed proteins. Thus, spatially specific regulation of protein adsorption on an implant surface is pivotal for mediating subsequent cellular behaviors. Unlike the surface modulation strategy for traditional biomaterials, in this research, materials with a nonuniform spatial distribution of surface charges were designed to achieve site-selective protein adsorption and further influence cell behavior by charge regulation. Spatially varying microdomains with different levels of piezoelectricity were generated via a focus laser beam-induced phase transition. In addition, after polarization, the zones with different levels of piezoelectricity showed significant differences in surface charge density. The results of scanning Kelvin probe force microscopy (SKPM) showed that the surface charge on the material exhibits a nonuniform spatial distribution after laser irradiation and polarization. Site-specific charge-mediated selective protein adsorption was demonstrated through a protein adsorption experiment. Cell behavior analysis showed that the increase in charge density was conducive to promoting cell adhesion and the formation of filopodia while the nonuniform spatial distribution of charge promoted an oriented arrangement of cells; both features accelerated cell migration. This study provides a new method for spatially regulating protein adsorption through surface charges to further influence cell behaviors.

An odorant receptor mediates the attractiveness of cis-jasmone to Campoletis chlorideae, the endoparasitoid of Helicoverpa armigera

Parasitic wasps rely on olfaction to locate their hosts in complex chemical environments. Odorant receptors (ORs) function together with well-conserved odorant coreceptors (ORcos) to determine the sensitivity and specificity of olfactory reception. Campoletis chlorideae (Hymenoptera: Ichneunmonidae) is a solitary larval endoparasitoid of the cotton bollworm, Helicoverpa armigera, and some other noctuid species. To understand the molecular basis of C. chlorideae's olfactory reception, we sequenced the transcriptome of adult male and female heads (including antennae) and identified 211 OR transcripts, with 95 being putatively full length. The tissue expression profiles, as assessed by reverse-transcription PCR, showed that seven ORs were expressed only or more highly in female antennae. Their functions were analysed using the Xenopu slaevis oocyte expression system and two-electrode voltage-clamp recordings. CchlOR62 was tuned to cis-jasmone, which was attractive to female C. chlorideae adults and H. armigera larvae in the subsequent behavioural assays. Further bioassays using caged plants showed that the parasitism rate of H. armigera larvae by C. chlorideae on cis-jasmone-treated tobacco plants was higher than on the control plants. Thus, cis-jasmone appears to be an important infochemical involved in the interactions of plants, H. armigera and C. chlorideae, and CchlOR62 mediates the attractiveness of cis-jasmone to C. chlorideae.

Elastomeric conductive hybrid hydrogels with continuous conductive networks

The DA–PPy–GP ECHs with continuous conductive networks show high force and strain sensitivity.

Nanomaterials as photothermal therapeutic agents

Curing cancer has been one of the greatest conundrums in the modern medical field. To reduce side-effects associated with the traditional cancer therapy such as radiotherapy and chemotherapy, photothermal therapy (PTT) has been recognized as one of the most promising treatments for cancer over recent years. PTT relies on ablation agents such as nanomaterials with a photothermal effect, for converting light into heat. In this way, elevated temperature could kill cancer cells while avoiding significant side effects on normal cells. This theory works because normal cells have a higher heat tolerance than cancer cells. Thus, nanomaterials with photothermal effects have attracted enormous attention due to their selectivity and non-invasive attributes. This review article summarizes the current status of employing nanomaterials with photothermal effects for anti-cancer treatment. Mechanisms of the photothermal effect and various factors affecting photothermal performance will be discussed. Efficient and selective PTT is believed to play an increasingly prominent role in cancer treatment. Moreover, merging PTT with other methods of cancer therapies is also discussed as a future trend.

Soft Conducting Polymer Hydrogels Cross-Linked and Doped by Tannic Acid for Spinal Cord Injury Repair

Mimicking soft tissue mechanical properties and the high conductivity required for electrical transmission in the native spinal cord is critical in nerve tissue regeneration scaffold designs. However, fabricating scaffolds of high conductivity, tissue-like mechanical properties, and excellent biocompatibility simultaneously remains a great challenge. Here, a soft, highly conductive, biocompatible conducting polymer hydrogel (CPH) based on a plant-derived polyphenol, tannic acid (TA), cross-linking and doping conducting polypyrrole (PPy) chains is developed to explore its therapeutic efficacy after a spinal cord injury (SCI). The developed hydrogels exhibit an excellent electronic conductivity (0.05-0.18 S/cm) and appropriate mechanical properties (0.3-2.2 kPa), which can be achieved by controlling TA concentration. In vitro, a CPH with a higher conductivity accelerated the differentiation of neural stem cells (NSCs) into neurons while suppressing the development of astrocytes. In vivo, with relatively high conductivity, the CPH can activate endogenous NSC neurogenesis in the lesion area, resulting in significant recovery of locomotor function. Overall, our findings evidence that the CPHs without being combined with any other therapeutic agents have stimulated tissue repair following an SCI and thus have important implications for future biomaterial designs for SCI therapy.

Integrated analysis of long noncoding RNA and mRNA expression profiles reveals the potential role of long noncoding RNA in different bovine lactation stages

Long noncoding RNA (lncRNA) play a critical role in mammary development and breast cancer biology. Despite their important role in the mammary gland, little is known of the roles of lncRNA in bovine lactation, particularly regarding the molecular processes underlying it. To characterize the role of lncRNA in bovine lactation, 4 samples of Holstein cow mammary gland tissue at peak and late lactation stages were examined after biopsy. We then profiled the transcriptome of the mammary gland using RNA sequencing technology. Further, functional lncRNA-mRNA coexpression pairs were constructed to infer the function of lncRNA using a generalized linear model, followed by gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. More than 1,000 putative lncRNA were identified, 117 of which were differentially expressed between peak and late lactation stages. Bovine lncRNA were shorter, with fewer exon numbers, and expressed at significantly lower levels than protein-coding genes. Seventy-two differentially expressed (DE) lncRNA were coexpressed with 340 different protein-coding genes. The KEGG pathway analysis showed that target mRNA for DE lncRNA were mainly related to lipid and glucose metabolism, including the peroxisome proliferator-activated receptors and 5' adenosine monophosphate-activated protein kinase signaling pathways. Further bioinformatics and integrative analyses revealed that 12 DE lncRNA potentially played important roles in bovine lactation. Our findings provide a valuable resource for future bovine transcriptome studies, facilitate the understanding of bovine lactation biology, and offer functional information for cattle lactation.