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Early osteoimmune microenvironment disorder at the interface between bone and implant can lead to implant loosening, which prolongs patient convalescence, exacerbates postoperative complications, and potentially results in implant failure. The timely regulation of macrophages primarily orchestrates the entire long‐term regeneration process. Here, it is proposed to precisely direct macrophage polarization using localized photoelectrical signals generated by an excitable surface in response to remote stimulation via near‐infrared light (NIR). The photocurrent generated from the n–n heterojunction between calcium titanate (CaTiO3) and defective titanium dioxide (TiO2‐Vo) on the excitable surface can accurately direct macrophage polarization, suppressing acute inflammation at the early stage of post‐implantation and establishing a favorable osteoimmune microenvironment that promotes bone‐to‐implant integration. Mechanistic study reveals that photoelectric signals initiate increased calcium influx via voltage‐gated calcium ion channels, subsequently modulating calcium/calmodulin‐dependent protein kinase kinase 2 (Camkk2) and calcium/calmodulin‐dependent protein kinase I (Camk1) expression to regulate macrophage polarization. This optimization of the osteoimmune microenvironment results in enhanced mesenchymal stem cells (MSCs) recruitment and osteogenesis, ultimately accelerating bone‐to‐implant integration within 14 days post‐implantation. This research presents a novel method for adjusting in vivo spatiotemporal immune responses through the use of noninvasive and externally‐controlled targeted stimulations. [ABSTRACT FROM AUTHOR]

Deep burns lead to extensive damage to the dermal layer, necessitating a longer treatment duration than typical skin injuries. Such burn wounds become more susceptible to drug‐resistant bacterial infections, thereby complicating and prolonging the therapeutic process. In this study, a unique spray composed of covalent metal hybrid‐linked organic frameworks (HLOF) material is developed that effectively eradicates methicillin‐resistant Staphylococcus aureus (MRSA) within 20 min by disrupting MRSA's surface electrons, destroying its cell membrane structure, and ultimately causing its demise with an impressive antibacterial rate of 96.7%. This HLOF material exhibited exceptional biological activity and stability. During the wound recovery procedure, HLOF promoted the expression of Vascular endothelial growthfactor(VEGF) to stimulate angiogenesis while inhibiting the proinflammatory factor Tumor necrosis factor alpha (TNF‐α) expression to eliminate inflammation and further enhance wound repair. This study presents an innovative approach for achieving outstanding antibacterial properties and improved biocompatibility through modifications made to common metal organic frameworks (MOFs), thus expanding their potential applications. [ABSTRACT FROM AUTHOR]

Intelligent control of the immune response is essential for obtaining percutaneous implants with good sterilization and tissue repair abilities. In this study, polypyrrole (Ppy) nanoparticles enveloping a 3D frame of sulfonated polyether ether ketone (SP) surface are constructed, which enhance the surface modulus and hardness of the sulfonated layer by forming a cooperative structure of simulated reinforced concrete and exhibit a superior photothermal effect. Ppy‐coated SP could quickly accumulate heat on the surface by responding to 808 nm near‐infrared (NIR) light, thereby killing bacteria, and destroying biofilms. Under NIR stimulation, the phagocytosis and M1 activation of macrophages cultured on Ppy‐coated SP are enhanced by activating complement 3 and its receptor, CD11b. Phagocytosis and M1 activation are impaired along with abolishment of NIR stimulation in the Ppy‐coated SP group, which is favorable for tissue repair. Ppy‐coated SP promotes Collagen‐I, vascular endothelial growth factor, connective tissue growth factor, and α‐actin (Acta2) expression by inducing M2 polarization owing to its higher surface modulus. Overall, Ppy‐coated SP with enhanced mechanical properties could be a good candidate for clinical percutaneous implants through on‐off phagocytosis and switchable macrophage activation stimulated with NIR. [ABSTRACT FROM AUTHOR]

The most critical factor determining the success of biodegradable bone implants is the host tissue response, which greatly depends on their degradation behaviors. Here, a new magnesium‐based implant, namely magnesium–silicon–calcium (Mg–0.2Si–1.0Ca) alloy, that coordinates its biodegradation along with the bone regenerative process via a self‐assembled, multilayered bone–implant interface is designed. At first, its rapid biocorrosion contributes to a burst release of Mg2+, leading to a pro‐osteogenic immune microenvironment in bone. Meanwhile, with the simultaneous intervention of Ca and Si in the secondary phases of the new alloy, a hierarchical layered calcified matrix is rapidly formed at the degrading interface that favored the subsequent bone mineralization. In contrast, pure Mg or Mg–0.2Si alloy without the development of this interface at the beginning will unavoidably induce detrimental bone loss. Hence, it is believed this biomimicking interface justifies its bioadaptability in which it can modulate its degradation in vivo and accelerate bone mineralization. [ABSTRACT FROM AUTHOR]

Some infectious or malignant diseases such as cancers are seriously threatening the health of human beings all over the world. The commonly used antibiotic therapy cannot effectively treat these diseases within a short time, and also bring about adverse effects such as drug resistance and immune system damage during long-term systemic treatment. Phototherapy is an emerging antibiotic-free strategy to treat these diseases. Upon light irradiation, phototherapeutic agents can generate cytotoxic reactive oxygen species (ROS) or induce a temperature increase, which leads to the death of targeted cells. These two kinds of killing strategies are referred to as photodynamic therapy (PDT) and photothermal therapy (PTT), respectively. So far, many photo-responsive agents have been developed. Among them, the metal–organic framework (MOF) is becoming one of the most promising photo-responsive materials because its structure and chemical compositions can be easily modulated to achieve specific functions. MOFs can have intrinsic photodynamic or photothermal ability under the rational design of MOF construction, or serve as the carrier of therapeutic agents, owing to its tunable porosity. MOFs also provide feasibility for various combined therapies and targeting methods, which improves the efficiency of phototherapy. In this review, we firstly investigated the principles of phototherapy, and comprehensively summarized recent advances of MOF in PDT, PTT and synergistic therapy, from construction to modification. We expect that our demonstration will shed light on the future development of this field, and bring it one step closer to clinical trials. [ABSTRACT FROM AUTHOR]

Long pulse, high frequency quasi-direct-current (dc) oxygen plasma immersion ion implantation (PIII) is utilized to create a superhydrophobic polytetrafluoroethylene (PTFE) surface with a water contact angle of over 150°. This technique allows the use of a high duty cycle without deleterious effects such as extensive sample heating encountered in conventional PIII. Scanning electron microscopy images review submicrometer-nanometer structures on the PTFE surface after long pulse, high frequency PIII indicative of ion implantation. On the other hand, plasma modification is the dominant effect in short pulse, low frequency PIII. Quasi-dc PIII is demonstrated to offer adjustable synergistic plasma and ion beam effects. [ABSTRACT FROM AUTHOR]

Prevention of implant-associated infections and insufficient bone tissue integration is critical to exploit the immunomodulatory properties and antibacterial effects of implant materials, which have attracted considerable attention. Modulation of the functions of immune cells in different environments is crucial for managing infection and inferior bone integration via immunomodulation. In this work, sodium butyrate, a fermentation product of gut microbiota, was loaded onto 3D porous sulfonated polyetheretherketone (SP) to modulate the immune responses of cells in different environments. Evaluation of in vitro antibacterial effects showed that sodium butyrate-loaded SP exhibited superior antibacterial activity, especially in the samples containing high concentrations of sodium butyrate. Under bacterial stimulation, the phagocytic activity of macrophages increased with an increase in the sodium butyrate concentration via the production of reactive oxygen species (ROS), which favoured bactericidal activity in the implant-associated infection stage. For bacterial elimination, sodium butyrate-containing SP could polarize macrophages to the M2 phenotype and subsequently stimulate anti-inflammatory cytokine secretion, which is considered beneficial for bone regeneration in the tissue repair stage. In vitro osteogenesis was evaluated and the results demonstrated that treatment with sodium butyrate-containing SP increased the expression of osteogenic genes and proteins. An in vivo rat osteomyelitis model was used to evaluate the protective effect of the SP-loaded with sodium butyrate on bone destruction and osteolysis under infection conditions. To study osteogenesis in vivo, a rat femoral model without infection was used. The results indicated that the SP-B2 group exhibited superior anti-infection capacity and induced new bone formation around the implant in vivo. Treatment with sodium butyrate-containing porous SP modulated the macrophage response under different stimuli, thereby serving as a new approach for the design of smart implant materials with superior antibacterial and bone repair properties. [ABSTRACT FROM AUTHOR]

Implant failures still happen because of bacterial infections and inferior osteogenic properties. Graphene oxide (GO) could induce osteogenic differentiation as well as exhibit superior antibacterial activity which may provide an answer for this issue. In this work, GO films loaded with minocycline hydrochloride (MH) were fabricated on titanium implant surfaces, and the antibacterial activity and osteogenic properties were studied in the presence of S. aureus and rat bone mesenchymal stem cells (rBMSCs) in in vitro and in vivo environments, respectively. The results indicated that the MH loaded GO films on titanium surfaces (MH&GO@Ti) exhibited enhanced osteogenic activity in vitro with improved alkaline phosphatase (ALP) activity and enhanced osteogenic related gene expressions including ALP, collagen-I, osteocalcin, and osteopontin. The in vitro results of the co-culture of rBMSCs and S. aureus indicated that the rBMSCs grew well on the MH&GO@Ti sample with a higher coverage of cells and the bacteria were almost unobservable on the surface. In the in vivo experiments, the MH&GO@Ti exhibited excellent antibacterial and osteogenic activities in the presence of bacteria. No inflammatory cells for example neutrophils were found and superior bone–implant integration was obtained. This study offers a new proposal for the clinical application of drug-loaded graphene coating. [ABSTRACT FROM AUTHOR]

The rapidly intensifying process of ocean acidification (OA) due to anthropogenic CO2 is not only depleting carbonate ions necessary for calcification but also causing acidosis and disrupting internal pH homeostasis in several marine organisms. These negative consequences of OA on marine calcifiers, i.e. oyster species, have been very well documented in recent studies, however, the consequences of reduced or impaired calcification on the end-product, shells or skeletons, still remain one of the major research gaps. Shells produced by marine organisms under OA are expected to show signs of dissolution, disorganized microstructure and reduced mechanical properties. To bridge this knowledge gap and to test the above hypothesis, we investigated the effect of OA on juvenile shells of the commercially important oyster species, Magallana angulata, at ecologically and climatically relevant OA levels (using pH 8.1, 7.8, 7.5, 7.2). In lower pH conditions, a drop of shell hardness and stiffness was revealed by nanoindentation tests, while an evident porous internal microstructure was detected by scanning electron microscopy. Crystallographic orientation, on the other hand, showed no significant difference with decreasing pH using electron back-scattered diffraction (EBSD). These results indicate the porous internal microstructure may be the cause of the reduction in shell hardness and stiffness. The overall decrease of shell density observed from micro-computed tomography analysis indicates the porous internal microstructure may run through the shell, thus inevitably limiting the effectiveness of the shell's defensive function. This study shows the potential deterioration of oyster shells induced by OA, especially in their early life stage. This knowledge is critical to estimate the survival and production of edible oysters in the future ocean. [ABSTRACT FROM AUTHOR]

The rapidly intensifying process of ocean acidification (OA) in coastal areas due to anthropogenic CO2 is not only depleting carbonate ions necessary for calcification but also causing acidosis and disrupting internal pH homeostasis in several marine organisms. These negative consequences of OA on marine communities, particularly to shellfish oyster species, has been very well documented in recent studies, however, the consequences of these reduced or impaired calcification processes on the end-product, shells or skeletons, still remains one of the major research gaps. Shells produced by marine organisms under OA are expected to be corroded with disorganized or impaired crystal orientation or microstructures with reduced mechanical property. To bridge this knowledge gap and to test the above hypothesis, we investigated the effect of OA on shell of the commercially important oyster species (Crassostrea angulata) at ecologically and climatically relevant OA levels (using pH 8.1, 7.8, 7.5, 7.2 as proxies). In decreased pH conditions, a drop of shell hardness and stiffness was revealed by nanoindentation tests, while an evident loosened internal microstructure was detected by scanning electron microscopy (SEM). In contrary, the crystallographic orientation of oyster shell showed no significant difference with decreasing pH by Electron Back Scattered Diffraction (EBSD) analyses. These results indicate the loosened internal microstructure may be the cause of the OA induced reduction in shell hardness and stiffness. Micro-computed tomography analysis (Micro-CT) indicated that an overall "down-shifting" of mineral density in the shell with decreasing pH, which implied the loosened internal microstructure may run through the shell, thus inevitably limiting the effectiveness of the shell defensive function. This study surfaces potential bottom-up deterioration induced by OA on oyster shells, especially in their early juvenile life stage. This knowledge is critical to forecast the survival and production of edible oysters in future ocean. [ABSTRACT FROM AUTHOR]

Abstract: Understanding cell–biomaterial interactions is critical for the control of cell fate for tissue engineering and regenerative medicine. Here, cerium oxide nanoparticles (CeONPs) are applied at different Ce4+/Ce3+ ratios (i.e., 0.46, 1.23, and 3.23) to titanium substrate surfaces by magnetron sputtering and vacuum annealing. Evaluation of the cytotoxicity of the modified surface to cultured rat bone marrow mesenchymal stem cells (BMSCs) reveals that the cytocompatibility and cell proliferation are proportional to the increases in Ce4+/Ce3+ ratio on titanium surface. The bone formation capability induced by these surface modified titanium alloys is evaluated by implanting various CeONP samples into the intramedullary cavity of rat femur for 8 weeks. New bone formation adjacent to the implant shows a close relationship to the surface Ce4+/Ce3+ ratio; higher Ce4+/Ce3+ ratio achieves better osseointegration. The mechanism of this in vivo outcome is explored by culturing rat BMSCs and RAW264.7 murine macrophages on CeONP samples for different durations. The improvement in osteogenic differentiation capability of BMSCs is directly proportional to the increased Ce4+/Ce3+ ratio on the titanium surface. Increases in the Ce4+/Ce3+ ratio also elevate the polarization of the M2 phenotype of RAW264.7 murine macrophages, particularly with respect to the healing‐associated M2 percentage and anti‐inflammatory cytokine secretion. The manipulation of valence states of CeONPs appears to provide an effective modulation of the osteogenic capability of stem cells and the M2 polarization of macrophages, resulting in favorable outcomes of new bone formation and osseointegration. [ABSTRACT FROM AUTHOR]

Nanocomposite hydrogels consist of a polymer matrix embedded with nanoparticles (NPs), which provide the hydrogels with unique bioactivities and mechanical properties. Incorporation of NPs via in situ precipitation in the polymer matrix further enhances these desirable hydrogel properties. However, the noncytocompatible pH, osmolality, and lengthy duration typically required for such in situ precipitation strategies preclude cell encapsulation in the resultant hydrogels. Bisphosphonate (BP) exhibits a variety of specific bioactivities and excellent binding affinity to multivalent cations such as magnesium ions (Mg2+). Here, the preparation of nanocomposite hydrogels via self-assembly driven by bisphosphonate-Mg2+ coordination is described. Upon mixing solutions of polymer bearing BPs, BP monomer (Ac-BP), and Mg2+, this effective and dynamic coordination leads to the rapid self-assembly of Ac-BP-Mg NPs which function as multivalent crosslinkers stabilize the resultant hydrogel structure at physiological pH. The obtained nanocomposite hydrogels are self-healing and exhibit improved mechanical properties compared to hydrogels prepared by blending prefabricated NPs. Importantly, the hydrogels in this study allow the encapsulation of cells and subsequent injection without compromising the viability of seeded cells. Furthermore, the acrylate groups on the surface of Ac-BP-Mg NPs enable facile temporal control over the stiffness and crosslinking density of hydrogels via UV-induced secondary crosslinking, and it is found that the delayed introduction of this secondary crosslinking enhances cell spreading and osteogenesis. [ABSTRACT FROM AUTHOR]

Cartilage loss is a leading cause of disability among adults, and effective therapy remains elusive. Human mesenchymal stem cells (hMSCs), which have demonstrated self-renewal and multipotential differentiation, are a promising cell source for cartilage repair. However, the hypertrophic differentiation of the chondrogenically induced MSCs and resulting tissue calcification hinders the clinical translation of MSCs for cartilage repair. Here, a multifunctional nanocarrier based on quantum dots (QDs) is developed to enhance chondrogenic differentiation and suppress hypertrophy of hMSCs simultaneously. Briefly, the QDs are modified with β-cyclodextrin (β-CD) and RGD peptide. The resulting nanocarrier is capable of carrying hydrophobic small molecules such as kartogenin in the hydrophobic pockets of conjugated β-CD to induce chondrogenic differentiation of hMSCs. Meanwhile, via electrostatic interaction the conjugated RGD peptides bind the cargo siRNA targeting Runx2, which is a key regulator of hMSC hypertrophy. Furthermore, due to the excellent photostability of QDs, hMSCs labeled with the nanocarrier can be tracked for up to 14 d after implantation in nude mice. Overall, this work demonstrates the potential of our nanocarrier for inducing and maintaining the chondrogenic phenotype and tracking hMSCs in vivo. [ABSTRACT FROM AUTHOR]

Calcium phosphate cements (CPCs) have long been used as osteoconductive bone substitutes in the treatment of bone defects. However, the degradation rate of CPC is typically too slow to match the new bone growth rate. It is known that strontium increases the solubility of hydroxyapatite as well as exerts both anabolic and anticatabolic effects on bone. Therefore, we hypothesized that the incorporation of strontium would accelerate the degradation rate and enhance the osteoconductivity of CPC. In this study, Three groups, CPC (0% Sr-CPC), 5% Sr-CPC, and 10% Sr-CPC, were prepared, with the total molar ratio for Sr/(Sr+Ca) in the cement powder phase being 0, 5, and 10%, respectively. In the immersion test, less residual weight was observed in both 5% Sr-CPC and 10% Sr-CPC groups than CPC group. In addition, a higher osteoblastic cell proliferation rate and alkaline phosphatase activity were obtained in the strontium groups. In a rat femur bone defect model comparing CPC with 10% Sr-CPC, at 2 weeks postoperation, early endochondral ossification was found in the 10% Sr-CPC group, whereas only fibrous tissue was observed in control group; at 4-16 weeks postoperation, progressive osteoconduction toward the cement was observed in both groups. At 32 weeks, a higher peri-cement bone area and reduced cement area were noted in the 10% Sr-CPC group. In conclusion, in the 10% Sr-CPC group, strontium exerts dual effects on CPC: accelerating degradation rate and enhancing osteoconductivity, as shown here both in vitro and in vivo. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 1613-1621, 2015. [ABSTRACT FROM AUTHOR]

Background: In vitro experiments on the functional roles of extracellular matrix (ECM) components usually involve the culture of cells on surfaces coated with purified ECM components. These experiments can seldom recuperate the spatial arrangement of ECM found in vivo. In this study, we have overcome this obstacle by using histological sections of bovine Achilles tendon as cell culture substrates. Results: We found that tendon sections can be viewed as a pre-formed block of ECM in which the collagen fibrils exhibited a spatial regularity unraveled in any artificially constructed scaffold. By carving the tendon at different angles relative to its main axis, we created different surfaces with distinct spatial arrangements of collagen fibrils. To assess the cellular responses to these surfaces, human mesenchymal stem cells (MSCs) were directly cultured on these sections, hence exposed to the collagen with different spatial orientations. Cells seeded on longitudinal tendon sections adopted a highly elongated and aligned morphology, and expressed an increased level of tenomodulin, suggesting that the collagen fibrils present in this section provide a microenvironment that facilitates cell morphogenesis and differentiation. However, MSC elongation, alignment and induction of tenomodulin diminished dramatically even as the sectioned angle changed slightly. Conclusion: Our results suggest that cell functions are influenced not only by the type or concentration of ECM components, but also by the precise spatial arrangements of these molecules. The method developed in this study offers a simple and robust way for the studying of cell-ECM interactions, and opens many research avenues in the field of matrix biology. [ABSTRACT FROM AUTHOR]

A series of co-polyimide/attapulgite (co-PI/AT) nanocomposites have been successfully fabricated from anhydride-terminated polyimide (PI) and γ-aminopropyltriethoxysilane (APTES)-modified fibrous attapulgite (AT). Co-PI was prepared from 4,4′-diaminodiphenyl ether (ODA), 4,4′-oxydiphthalic anhydride (ODPA), and 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA) by using the method of chemical imidization. Different amount of AT (0, 1, 3, 5, 7 wt%) were introduced into co-PI via strong covalent interactions between terminal anhydride and amino groups. The properties of co-PI/AT nanocomposites such as morphology, thermal stability, mechanical properties, and UV transparency were investigated to illustrate the contribution of the introduction of AT into the PI matrix. FTIR spectra and SEM images revealed that network structures between co-PI and AT are formed, which endowed the nanocomposites with outstanding thermal and mechanical properties. The co-PI/AT nanocomposites exhibited excellent thermal and thermo-oxidative stabilities with the onset decomposition temperature and 10% weight loss temperature increasing to the ranges of 502-510°C and 555-562°C from 480°C to 526°C for the pristine co-PI, respectively. The glass transition temperatures of these co-PI/AT nanocomposites increased to the range of 231-238°C from 222°C for pure co-PI. The co-PI/AT nanocomposites films were found to be transparent, flexible, and tough. By incorporating 5 wt% AT into the co-PI matrix, the tensile strength, elongation at break, and Young's modulus of the co-PI/AT nanocomposites reached 110.7 MPa, 14.5%, and 1.2 GPa, respectively, which are 50%, 120%, and 80% increased compared with the values of pristine PI. POLYM. COMPOS., 35:86-96, 2014. © 2013 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

ABSTRACT Novel pyridine-containing hyperbranched polyimides (HBPIs) were synthesized by using a new triamine 2,4,6-tris[3-(4-aminophenoxy)phenyl]pyridine with prolonged chain segments, ether linkage and meta-linked units as a BB′2-like monomer, various commercial aromatic dianhydrides as A2 monomers. Most of the obtained HBPIs were readily soluble in common organic solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, m-Cresol, and so forth. Meanwhile, they also had good thermal stability with the glass transition temperatures ( Tgs) all above 210 °C, the temperature at 10% weight loss of 537.1-574.4 °C in nitrogen atmosphere. Strong and flexible HBPI films were obtained, which had good mechanical properties with tensile strengths of 83.3-95.8 MPa, tensile modulus of 1.82-2.43 GPa and elongations at break of 4.84-6.98%. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2425-2437 [ABSTRACT FROM AUTHOR]

A novel fluorinated pyridine-containing aromatic diamine monomer, 4-phenyl-2,6-bis[2-(4-amino-2-trifluoromethyphenoxy)phenyl]pyridine (o, p-6FPAPP), was prepared in a three-step synthetic route. This aromatic diamine was then employed to synthesize a series of fluorinated pyridine-containing polyimides (PIs) by polycondensation with various aromatic dianhydrides via the conventional two-step method. The inherent viscosities of the resulting poly(amic acid)s (PAAs) and PIs were in the range of 0.71–0.89 and 0.62–0.84 dL/g; all the PIs obtained by chemical imidization were readily soluble in common organic solvents such as N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF) and so on. Meanwhile, transparent, strong and flexible PI films were obtained, which had good thermal stability, with the glass transition temperature (Tg) of 195.2°C–232.7°C, the temperature at 10% weight loss of 530.2°C–546.0°C in nitrogen atmosphere, and good optical transparency with the cutoff wavelengths of 354–382 nm, as well as outstanding mechanical properties with tensile strengths of 96.4–105.8 MPa, tensile modulus of 1.57–1.88 GPa and elongations at break of 9.5%–13.4%. The PI films were also found to possess low water uptake of 0.52%–0.67%. [ABSTRACT FROM PUBLISHER]

A novel pyridine-containing aromatic diamine monomer, 4-(4-trifluoromethylphenyl)-2,6-bis[3-(4-aminophenoxy)phenyl]pyridine (m,p-3FPAPP), was successfully synthesized by a modified Chichibabin reaction of 4-trifluoromethylbenzaldehyde and a substituted acetophenone, 3-(4-nitrophenoxy)acetophenone (m,p-NPAP), followed by a reduction of the resulting dinitro compound 4-(4-trifluoromethylphenyl)-2,6bis[3-(4-nitrophenoxy)phenyl] pyridine (m,p-3FPNPP) with Pd/C and hydrazine monohydrate. The aromatic diamine was employed to synthesize a series of pyridine-containing polyimides by polycondensation with various aromatic dianhydrides in N,N-dimethylformamide (DMF) via the conventional two-step method, and further thermal or chemical imidization forming polyimides. The inherent viscosities of the resulting poly(amic acid)s and polyimides were 0.62-0.89 and 0.58-0.69 dl/g, and most of the polyimides obtained by chemical imidization were readily soluble in common organic solvents such as DMF, N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP) and tetrahydrofuran (THF). Meanwhile, strong and flexible polyimide films were obtained, which had good thermal stability, with a glass transition temperature (Tg) of 234.4-246.6°C and the temperature at 10% weight loss of 561.4-600.6°C in nitrogen atmosphere, and good optical transparency with the cut-off wavelengths of 369-378 nm, as well as outstanding mechanical properties with tensile strengths of 89.5-96.4 MPa, a tensile modulus of 1.52-1.63 GPa and elongation-at-break of 7.2-8.7%. The polyimide films also were found to possess low water uptake (0.61-0.79%). [ABSTRACT FROM AUTHOR]

A biomaterials surface enabling the induction of tumor cell death is particularly desirable for implantable biomedical devices that directly contact tumor tissues. However, this specific antitumor feature is rarely found. Consequently, an antitumor‐cell nanocoating comprised of vanadium dioxide (VO2) prepared by customized reactive magnetron sputtering has been proposed, and its antitumor‐growth capability has been demonstrated using human cholangiocarcinoma cells. The results reveal that the VO2 nanocoating is able to interrupt the mitochondrial electron transport chain and then elevate the intracellular reactive oxygen species levels, leading to the collapse of the mitochondrial membrane potential and the destruction of cell redox homeostasis. Indeed, this chain reaction can effectively trigger oxidative damage in the cholangiocarcinoma cells. Additionally, this study has provided new insights into designing a tumor‐cell‐inhibited biomaterial surface, which is modulated by the mechanism of mitochondria‐targeting tumor cell death. Vanadium dioxide (VO2) nanocoating with tunable film thickness is deposited on quartz glass surface by reactive magnetron sputtering. The VO2 nanocoating can impose significant anticancer effects on human tumor cells by releasing vanadate ions to interact with mitochondria and thereby trigger tumor cell apoptosis, demonstrating the promise of VO2 nanocoating for antitumor surface design of biomaterials for cancer treatments. [ABSTRACT FROM AUTHOR]

The cytokines released by immune cells are considered important factors to induce bone tissue regeneration. However, the pathway of those bone‐targeting macrophage cytokines induced by biomaterial surface under tissue microenvironment is rarely reported. In this study, the immunomodulatory capability of zinc ions on macrophage polarization and its effects on osteogenic differentiation are investigated. Hence, a layer of zinc ions are incorporated on sulfonated polyetheretherketone (SPEEK) biomaterials by using a customized magnetron sputtering technique. The results reveal that the microenvironment on Zn‐coated SPEEK can modulate nonactivated macrophage polarization to an anti‐inflammatory phenotype and induce the secretion of anti‐inflammatory and osteogenic cytokines. The osteogenic differentiation capability of bone marrow stromal cells (BMSCs) is therefore enhanced, leading to improved osteointegration between the zinc‐coated SPEEK and bone tissue. This study verifies that zinc ion is a promising additive in the osteoimmunomodulation process and provides knowledge that may pave the way to develop the next generation of immunomodulatory biomaterials. Zinc‐modified sulfonated polyetheretherketone (SPEEK) is fabricated by sulfonation and magnetron sputtering. The immunomodulatory Zn‐coated SPEEK can induce macrophage polarization to the M2 phenotype. Then, the M2 macrophages secrete anti‐inflammatory and osteogenic cytokines to improve osteogenesis both in vitro and in vivo. [ABSTRACT FROM AUTHOR]

The study also demonstrates the presence of zinc ions to promote fibroblast proliferation and support acne recovery. Sodium hyaluronate was used as a raw material for the microneedles, and the zinc porphyrin-based MOF and zinc oxide were synthesized and loaded into the microneedles. The ultrasound responsive materials can produce reactive oxygen species under ultrasound excitation, and the interface effect between the composite materials can greatly improve the sonocatalytic performance.

Despite many investigations on the corrosion behavior of NiTi shape memory alloys (SMAs) in various simulated physiological solutions by electrochemical measurements, few have reported detailed information on the corrosion products. In the present study, the structure and composition of the corrosion products on NiTi SMAs immersed in a 0.9% NaCl physiological solution are systematically investigated by scanning electron microscopy (SEM), x-ray energy dispersion spectroscopy (EDS), and x-ray photoelectron spectroscopy (XPS). It is found that attack by Cl- results in nickel being released into the solution and decrease in the local nickel concentration at the pitting sites. The remaining Ti reacts with dissolved oxygen from the solution to form titanium oxides. After long-term immersion, the corrosion product layer expands over the entire surface and XPS reveals that the layer is composed of TiO2, Ti2O3, and TiO with relatively depleted Ni. The growth rate of the corrosion product layer decreases with immersion time, and the corrosion product layer is believed to impede further corrosion and improve the biocompatibility of NiTi alloy in a physiological environment. It is found that the release rate of nickel is related to the surface structure of the corrosion product layer and immersion time. A corrosion mechanism is proposed to explain the observed results. [ABSTRACT FROM AUTHOR]

Achieving bacterial killing and osteogenic formation on an implant surface rarely occurs. In this study, a novel surface design-a palladium hydride (PdH x ) film that enables these two distinct features to coexist is introduced. The PdH x lattice captures protons in the extracellular microenvironment of bacteria, disrupting their normal metabolic activities, such as ATP synthesis, nutrient co-transport, and oxidative stress. This disruption leads to significant bacterial death, as evidenced by RNA sequence analysis. Additionally, the unique enzymatic activity and hydrogen-loading properties of PdH x activate the human antioxidant system, resulting in the rapid clearance of reactive oxygen species. This process reshapes the osteogenic immune microenvironment, promoting accelerated osteogenesis. These findings reveal that the downregulation of the NOD-like receptor signaling pathway is critical for activating immune cells toward M2 phenotype polarization. This novel surface design provides new strategies for modifying implant coatings to simultaneously prevent bacterial infection, reduce inflammation, and enhance tissue regeneration, making it a noteworthy contribution to the field of advanced materials., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)

Infection and poor tissue repair are the key causes of percutaneous implantation failure. However, there is a lack of effective strategies to cope with due to its high requirements of sterilization, soft tissue healing, and osseointegration. In this work, l-arginine (L-Arg) was loaded onto a sulfonated polyetheretherketone (PEEK) surface to solve this issue. Under the infection condition, nitric oxide (NO) and reactive oxygen species (ROS) are produced through catalyzing L-Arg by inducible nitric oxide synthase (iNOS) and thus play a role in bacteria sterilization. Under the tissue repair condition, L-Arg is catalyzed to ornithine by Arginase-1 (Arg-1), which promotes the proliferation and collagen secretion of L929 and rBMSCs. Notably, L-Arg loading samples could polarize macrophages to M1 and M2 in infection and tissue repair conditions, respectively. The results in vivo show that the L-Arg loading samples could enhance infected soft tissue sealing and bone regeneration. In summary, L-Arg loading sulfonated PEEK could polarize macrophage through metabolic reprogramming, providing multi-functions of antibacterial abilities, soft tissue repair, and bone regeneration, which gives a new idea to design percutaneous implantation materials., Competing Interests: Kelvin W. K. Yeung is an associate editor for Bioactive Materials and was not involved in the editorial review or the decision to publish this article. Xuanyong Liu is an editorial board member for Bioactive Materials and was not involved in the editorial review or the decision to publish this article. All authors declare that there are no competing interests., (© 2024 The Authors.)