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Inflammation and depression are serious complications of diabetes that interact to form a feedback loop and may hinder diabetic wound healing. They share a common pathophysiological basis of abnormal interactions between diabetic wounds and the brain. Here, we propose a strategy combining electroacupuncture (EA) stimulation of the Dazhui acupoint (GV14) with polyphenol-mediated conductive hydrogel microneedles to promote diabetic wound healing and alleviate depression through local wound–brain interactions. The conductive microneedles comprised methacrylated gelatin, dopamine (DA), DA-modified poly(3,4-ethylenedioxythiophene), and Lycium barbarumpolysaccharide. EA at GV14 activated the vagus–adrenal axis to inhibit systemic inflammation while DA coupled electrical signals for long-term inhibition of local wound inflammation. EA at GV14 was also found to elevate 5-hydroxytryptamine levels in rats with diabetic wounds, consequently mitigating depressive-like behaviors. Additionally, the polyphenol-mediated conductive hydrogel microneedles, and coupled with EA stimulation promoted healing of wound tissue and peripheral nerves. This strategy regulated both local and systemic inflammation while alleviating depressive-like behaviors in diabetic rats, providing a new clinical perspective for the treatment of diabetes-related and emotional disorders.

An essential challenge in diabetic periodontal regeneration is achieving the transition from a hyperglycemic inflammatory microenvironment to a regenerative one. Here, we describe a polydopamine (PDA)-mediated ultralong silk microfiber (PDA-mSF) and metformin (Met)-loaded zeolitic imidazolate framework (ZIF) incorporated into a silk fibroin/gelatin (SG) patch to promote periodontal soft and hard tissue regeneration by regulating the immunomodulatory microenvironment. The PDA-mSF endows the patch with a reactive oxygen species (ROS)-scavenging ability and anti-inflammatory activity, reducing the inflammatory response by suppressing M1 macrophage polarization. Moreover, PDA improves periodontal ligament reconstruction via its cell affinity. Sustained release of Met from the Met-ZIF system confers the patch with antiaging and immunomodulatory abilities by activating M2 macrophage polarization to secrete osteogenesis-related cytokines, while release of Zn2+also promotes bone regeneration. Consequently, the Met-ZIF system creates a favorable microenvironment for periodontal tissue regeneration. These features synergistically accelerate diabetic periodontal bone and ligament regeneration. Thus, our findings offer a potential therapeutic strategy for hard and soft tissue regeneration in diabetic periodontitis.

Antibacterial hydrogel wound dressings have attracted considerable attention in recent years. However, bacterial infections can occur at any point during the wound-healing process. There is a demand for hydrogels that possess on-demand antibacterial and excellent wound repair properties. Herein, we report a near-infrared (NIR)-light-responsive indocyanine green (ICG)-loaded polydopamine (PDA)-mediated graphene oxide (PGO) and amorphous calcium phosphate (CaP)-incorporated poly(vinyl alcohol) (PVA) hydrogel using a mussel-inspired approach. PGO was reduced by PDA, which endowed the hydrogel with electroactivity and provided abundant sites for loading ICG. Amorphous CaP was formed in situ in the PVA hydrogel to enhance its mechanical properties and biocompatibility. Taking advantage of the high photothermal and photodynamic efficiency of ICG-PGO, the ICG-PGO-CaP-PVA hydrogel exhibited fascinating on-demand antibacterial activity through NIR light irradiation. Moreover, the thermally induced gel–sol conversion of PVA accelerated the release of Ca ions and allowed the hydrogel to adapt to irregular wounds. Meanwhile, PGO endows the hydrogel with conductivity and cell affinity, which facilitate endogenous electrical signal transfer to control cell behavior. In vitro and in vivo studies demonstrated that the ICG-PGO-CaP-PVA hydrogel exhibited a strong tissue repair activity under NIR light irradiation. This mussel-inspired strategy offers a novel way to design hydrogel dressings for wound healing.

Effective wound sealing is key to prevent postoperative complications arising from gastric endoscopic submucosal dissection (ESD). Accurate delivery of the adhesive to wet and dynamic tissues and rapid action of the adhesive onsite should be considered for endoscopic operation. A hybrid dry powder (HDP) strategy, characterized by decoupling of powder gelation and tissue adhesion, for rapid sealing of wet tissues is presented. HDPs carrying oppositely charged polyelectrolytes become a hydrogel layer over the target tissue by absorbing the surrounding water and forming strong electrostatic interactions between heterogeneous components. Strong adhesion is realized through hydrogen bonding between the adhesive component, poly(acrylic acid), and the tissue. Wet tissue adhesion can be achieved in a few seconds (adhesion strength of ∼30 kPa to porcine skin). Notably, the HDP-assembled hydrogel can maintain a low swelling rate and resist degradation in acidic aqueous environments (pH 1). Furthermore, HDPs can be delivered to target tissues by spraying via an endoscope. The results of in vivo experiments indicate that healing of gastric ESD perforations by sealing with the powder-assembled hydrogel is as effective as that by sealing with clips. This strategy is expected to facilitate the development of fast-acting hydrogel-based adhesives for endoscopic operation.

Hydrogels with robust wet adhesion are desirable for applications in aqueous environments. Wet adhesion arising from synergy between hydrophobic and catechol components in mussel foot proteins has been highlighted. However, optimizing hydrogels with multiple components is challenging because of their complex structure–property relationships. Herein, high-throughput screening of a series of hydrophobic alkyl monomers and adhesive catechol derivatives was used to systematically develop wet adhesive hydrogels. Short alkyl chains promote wet adhesion by repelling water at the adhesive interface, whereas long alkyl chains form strong hydrophobic interactions inside the hydrogel network that impede or dissipate energy for wet adhesion. The optimized wet adhesive hydrogel, containing short alkyl chain, was applied for rapid hemostasis and wound healing because of the synergistic effect of catechol and alkyl groups and its immunomodulation ability, which is revealed through a transcriptomic analysis. Conductive nanocomponents were incorporated into the optimized hydrogel to produce a wearable device, which was used for continuous monitoring human electrocardiogram (ECG) during swimming, and in situ epicardial ECG on a porcine living and beating heart. This study demonstrated an efficient and generalized molecular design strategy for multifunctional wet adhesive hydrogels.

Stretchable and conductive hydrogels are rapidly emerging as new generation candidates for wearable devices. However, the poor electroactivity and bioadhesiveness of traditional conductive hydrogels has limited their applications. Herein, a mussel-inspired strategy is proposed to prepare a specific core–shell redox-active system, consisting of a polydopamine (PDA) modified zeolitic imidazolate framework 71 (ZIF-71) core, and a poly 3,4-ethylenedioxythiopene (PEDOT) shell. Owing to the abundant catechol groups, PEDOT can be assembled on the surface of ZIF-71 to create a redox-active system. The core–shell nanoparticles could act as a redox-active nanofiller to develop a conductive polyacrylamide (PAM) hydrogel with energy-storage properties. The core–shell PEDOT@PZIF-71 system provides a mussel-inspired environment in the hydrogel matrix and endows the hydrogel with stretchability and adhesiveness. The hydrogel can be applied as a functional electrode for both bioelectronics and supercapacitors. Moreover, this hydrogel exhibits favorable biocompatibility and can be implanted in vivofor biosignal measurement without causing inflammation. This redox-active core–shell PEDOT@PZIF-71 system provides a promising strategy for the design of hydrogel-based wearable electronic devices.

Bioadhesive gels with robust adhesion on wet and irregular tissue surfaces are desirable for clinical applications. Assembly of bioadhesive powders is an effective strategy for obtaining gels that adhere to wet and irregular tissue surfaces by absorbing interfacial water. However, current bioadhesive powders lack positive biological functions and are prone to postoperative adhesion. Here, we present a powder strategy based on metal-ligand coordination to create a series of bioadhesive polyacrylic acid (PAA) gels. In the gel network, metal ions (Mn+) are used to coordinate with the carboxy ligands of PAA to form dynamic noncovalent crosslinks. The powders can absorb interfacial water and assemble into gels on wet and irregular tissue surfaces within a few seconds, forming an initial adhesion layer by electrostatic interactions. Furthermore, the polymers can diffuse into the tissue matrix, and metal-ligand coordination is reconstructed to enhance the adhesion. Moreover, with a cationic shield layer, the bioadhesive powders can effectively avoid postoperative adhesion. Importantly, ions endow the gel with customized biological functions. We demonstrate that the hemostatic, antibacterial, peroxidase-like catalytic, and photodetachment abilities of the gels by incorporating different Mn+ions. These advantages make the bioadhesive powder a promising platform for diverse tissue repair applications.

Brain-machine interfaces (BMIs) enable communication between the brain and external machines. However, mechanical and biological mismatches, as well as weak physical adhesion-induced shifts between rigid electronic devices and soft brain tissue, generally trigger a host immune response, affecting signal recording and reducing the lifespan of BMIs in clinics. Herein, we design a bioadhesive ultrasoft BMI based on integration of bioelectronics with a dopamine methacrylate-hybridized poly(3,4-ethylenedioxythiophene) nanoparticle (dPEDOT NP)-incorporated hydrogel with high conductivity. The hydrogel exhibits robust adhesiveness, enabling tight integration with metallic microcircuits and seamless adhesion to the brain tissue. Most importantly, the hydrogel exhibits a brain-level modulus that reduces its mechanical discrepancy with brain tissue. Meanwhile, the hydrogel possesses immune-evasive ability, which actively prevents fibrous tissue encapsulation and neuroinflammation after implantation. Consequently, the immune-evasive, bioadhesive, ultrasoft, and conductive hydrogel-integrated BMI permits long-term and accurate electroencephalographic signal acquisition and communication with minimal foreign body reaction.

Injury to articular cartilage cause certain degree of disability due to poor self-repair ability of cartilage tissue. To promote cartilage regeneration, it is essential to develop a scaffold that properly mimics the native cartilage extracellular matrix (ECM) in the aspect of compositions and functions.

Adhesive hydrogels have broad applications ranging from tissue engineering to bioelectronics; however, fabricating adhesive hydrogels with multiple functions remains a challenge. In this study, a mussel-inspired tannic acid chelated-Ag (TA-Ag) nanozyme with peroxidase (POD)-like activity was designed by the in situreduction of ultrasmall Ag nanoparticles (NPs) with TA. The ultrasmall TA-Ag nanozyme exhibited high catalytic activity to induce hydrogel self-setting without external aid. The nanozyme retained abundant phenolic hydroxyl groups and maintained the dynamic redox balance of phenol-quinone, providing the hydrogels with long-term and repeatable adhesiveness, similar to the adhesion of mussels. The phenolic hydroxyl groups also afforded uniform distribution of the nanozyme in the hydrogel network, thereby improving its mechanical properties and conductivity. Furthermore, the nanozyme endowed the hydrogel with antibacterial activity through synergistic effects of the reactive oxygen species generated via POD-like catalytic reactions and the intrinsic bactericidal activity of Ag. Owing to these advantages, the ultrasmall TA-Ag nanozyme-catalyzed hydrogel could be effectively used as an adhesive, antibacterial, and implantable bioelectrode to detect bio-signals, and as a wound dressing to accelerate tissue regeneration while preventing infection. Therefore, this study provides a promising approach for the fabrication of adhesive hydrogel bioelectronics with multiple functions via mussel-inspired nanozyme catalysis.

Photodynamic bonds are stable in the dark and can reversibly dissociate/form under light irradiation. Photodynamic bonds are promising building blocks for responsive or healable materials, photoactivated drugs, nanocarriers, extracellular matrices, etc. However, reactive intermediates from photodynamic bonds usually lead to side reactions, which limit the use of photodynamic bonds. Here, we report that the Ru–Se coordination bond is a new photodynamic bond that reversibly dissociates under mild visible-light-irradiation conditions. We observed that Ru–Se bonds form via the coordination of a selenoether ligand with [Ru(tpy)(biq)(H2O)]Cl2(tpy = 2,2′:6′,2″-terpyridine, biq = 2,2′-biquinoline) in the dark, while the Ru–Se bond reversibly dissociates under visible-light irradiation. No side reaction is detected in the formation and dissociation of Ru–Se bonds. To demonstrate that the Ru–Se bond is applicable to different operating environments, we prepared photoresponsive amphiphiles, surfaces, and polymer gels using Ru–Se bonds. The amphiphiles with Ru–Se bonds showed reversible morphological transitions between spherical micelles and bowl-shaped assemblies for dark/light irradiation cycles. The surfaces modified with Ru–Se-bond-containing compounds showed photoswitchable wettability. Polymer gels with Ru–Se cross-links underwent photoinduced reversible sol–gel transitions, which can be used for reshaping and healing. Our work demonstrates that the Ru–Se bond is a new type of dynamic bond, which can be used for constructing responsive, reprocessable, switchable, and healable materials that work in a variety of environments.

Tough and conductive hydrogels are the promising materials for various applications. However, fabrication of these hydrogels at room or low temperatures, without external stimuli, is a challenge. Herein, a novel dual self-catalytic system composed of a variety of metal ions and catechol-based molecules was developed to efficiently trigger the free-radical polymerization of tough, conductive, transparent, and self-healing hydrogels at low temperature without any external stimuli. Ferric ions (Fe3+) and dopamine (DA) were chosen as model compounds, which form stable redox pairs that act as a dual self-catalytic system to activate ammonium persulfate to generate free radicals. Consequently, the radicals could rapidly trigger the hydrogel self-gelation at low temperatures (6 °C) within 5 s. The dual self-catalytic system opens up a facile route to synthesize multifunctional hydrogels at mild conditions for a broad range of applications, especially in tissue engineering and wearable electronics.

Graphene oxide (GO) attracts considerable attention for biomedical applications owing to its unique nanostructure and remarkable physicochemical characteristics. However, it is challenging to uniformly deposit GO on chemically inert Ti scaffolds, which have good biocompatibility and wide applications in bone engineering. In this study, a GO-functionalized Ti porous scaffold (GO/Ti scaffold) was prepared by depositing GO onto polydopamine (PDA) modified Ti scaffolds. The mussel-inspired PDA modification facilitated the interaction between GO and Ti surfaces, leading to a uniform coverage of GO on Ti scaffolds. BMP2 and vancomycin (Van) were separately encapsulated into gelatin microspheres (GelMS). Then, drug-containing GelMS were assembled on GO/Ti scaffolds and anchored by the functional groups of GO. The modified scaffold independently delivered multiple biomolecules with different physiochemical properties, without interfering with each other. Thus, the GO/Ti scaffold has the dual functions of inducing bone regeneration and preventing bacterial infection. In summary, this mussel-inspired GO/Ti hybrid scaffold combined the good mechanical properties of Ti scaffolds and the advantages of GO nanosheets. GO nanosheets with their unique nanostructure and functional groups, together with GelMS on Ti scaffolds, are suitable carriers for drug delivery and provide adhesive sites for cell adhesion and create nanostructured environments for bone regeneration.

Polydopamine (PDA) is an important candidate material for the surface modification of biomedical devices because of its good adhesiveness and biocompatibility. However, PDA nanofilms lack osteoinductivity, limiting their applications in bone tissue engineering. Hydroxyapatite nanoparticles (HA-NPs) are the major component of natural bone, which can be used to effectively enhance the osteoinductivity of PDA nanofilms. Herein, we developed a pulse electrochemical driven layer-by-layer (PED-LbL) assembly process to rapidly deposit HA-NPs and PDA (HA-PDA) multilayer nanofilms. In this process, PDA and HA-NPs are in situsynthesized in two sequential oxidative and reductive pulses in each electrochemical deposition cycle and alternately deposited on the substrate surfaces. PDA assists the in situsynthesis of HA-NPs by working as a template, which avoids the noncontrollable HA nucleation and aggregation. The HA-PDA multilayer nanofilms serve as a tunable reservoir to deliver bone morphogenetic protein-2 and exhibit high osteoinductivity both in vitroand in vivo. This PED-LbL assembly process breaks the limitation of traditional LbL assembly, allowing not only the rapid assembly of oppositely charged polyelectrolytes but also the in situsynthesis of organic/inorganic NPs that are uniformly incorporated in the nanofilm. It has broad applications in the preparation of versatile surface coatings on various biomedical devices.

Biomimetic calcium phosphate mineralized graphene oxide/chitosan (GO/CS) scaffolds with hierarchical structures were developed. First, GO/CS scaffolds with large micropores (∼300 μm) showed high mechanical strength due to the electrostatic interaction between the oxygen-containing functional groups of GO and the amine groups of CS. Second, octacalcuim phosphate (OCP) with porous structures (∼1 μm) was biomimetically mineralized on the surfaces of the GO/CS scaffolds (OCP-GO/CS). The hierarchical microporous structures of OCP-GO/CS scaffolds provide a suitable environment for cell adhesion and growth. The scaffolds have exceptional adsorbability of nanoparticles. Bone morphogenetic protein-2 (BMP-2)-encapsulated bovine serum albumin (BSA) nanoparticles and Ag nanoparticles (Ag-NPs) were adsorbed in the scaffolds for enhancement of osteoinductivity and antibacterial properties, respectively. Antibacterial tests showed that the scaffolds exhibited high antibacterial properties against both Escherichia coliand Staphylococcus epidermidis. In vitro and in vivo experiments revealed that the scaffolds have good biocompatibility, enhanced bone marrow stromal cells proliferation and differentiation, and induced bone tissue regeneration. Thus, the biomimetic OCP-GO/CS scaffolds with immobilized growth factors and antibacterial agents might be excellent candidates for bone tissue engineering.

To better understand the Pan-African-early Paleozoic tectonothermal events of the Nyainrong microcontinent and the constraints on its tectonic evolution, here we report the results of zircon LA-ICP-MS U-Pb dating and geochemical features of Amdo gneiss in the Nyainrong microcontinent. The outcrops of Amdo gneiss is about 30 km south of Amdo County in northern Tibet. The field occurrence, mineral composition, textural characteristics, and whole-rock geochemical features of the four gneiss samples indicate the protolith of the gneisses is intermediate-acid intrusive rock. Gneiss zircon trace element tracing and genetic analysis shows that zircon has typical characteristics of magmatic zircon. The 206Pb/238U concordant age of zircon is 505–517 Ma, corresponding to the Middle-Late Cambrian, which is the formation age of the protolith. The samples have characteristics of high silicon, alkali-rich, alkalic rate AR =1.73–3.7, the differentiation index DI = 70.78–90.28; rock aluminum saturation index ranges from 1.02 to 1.05, FeO / MgO ranges from 2.63 to 4.50, 10000 × Ga/Al ranges from 2.12 to 2.41, and P2O5and Al2O3content decreased with SiO2increasing. Th and Y contents have a good positive correlation with Rb content; the genetic type of protolith of the gneiss is the differentiation of subalkaline over aluminum I-type granite. Combined with regional data, the tectonic setting of the Amdo gneiss protolith is closely related to the collision orogenic process. The preliminary view is that the Middle-Late Cambrian magmatic events developed on the microcontinent could be the result of Andean-type orogeny along the Gondwana super-continental margin after the end of the Pan-African orogeny.

Abstract: The high-pressure metamorphic belt (HPMB) of eclogite-blueschist in Central Qiangtang (羌塘) lies in the Longmu Co (龙木错)-Shuanghu (双湖) suture zone. To the west, the HPMB extends 500 km from Hongjishan (红脊山) to Caiduochaka (才多茶卡), east of Shuanghu; to the east it extends to Baqing (巴青) and Jitang (吉塘) in Qamdo (昌都), and then bends southward to Yunnan (云南) Province. Including the Lancangjiang (澜沧江) blueschist belt, the entire HPMB is about 2 000 km long. In Central Qiangtang, the belt is mainly composed of blueschist and eclogite, whereas in West Yunnan it contains only blueschist. The Baqing-Jitang segment is dominated by garnet phengite schist. 40Ar-39Ar dating of glaucophane and phengite from the blueschists yielded plateau ages ranging from 223 to 215 Ma, whereas SHRIMP U-Pb dating of zircon from the eclogites gives metamorphic ages of 243–217 Ma. The calculated metamorphic conditions for the blueschists are 410–460 °C and 0.67–0.75 GPa, and for the eclogites, <500 °C and 1.56–2.35 GPa. The metamorphic ages suggest that the Longmu Co-Shuanghu suture closed in the Late Triassic. The region south of the Longmu Co-Shuanghu-Lancang suture consists of the pan-African basement overlain by Gondwana sedimentary and meta-sedimentary rocks, whereas the region north of the suture is dominated by the Jinning (晋宁) basement and Yangtze sedimentary and metasedimentary rocks. The Qiangtang HPMB marks the closure of the paleo-Tethys Ocean.

Regenerating periodontal bone tissues in the aggravated inflammatory periodontal microenvironment under diabetic conditions is a great challenge. Here, a polydopamine-mediated graphene oxide (PGO) and hydroxyapatite nanoparticle (PHA)-incorporated conductive alginate/gelatin (AG) scaffold is developed to accelerate periodontal bone regeneration by modulating the diabetic inflammatory microenvironment. PHA confers the scaffold with osteoinductivity and PGO provides a conductive pathway for the scaffold. The conductive scaffold promotes bone regeneration by transferring endogenous electrical signals to cells and activating Ca2+channels. Moreover, the scaffold with polydopamine-mediated nanomaterials has a reactive oxygen species (ROS)-scavenging ability and anti-inflammatory activity. It also exhibits an immunomodulatory ability that suppresses M1 macrophage polarization and activates M2 macrophages to secrete osteogenesis-related cytokines by mediating glycolytic and RhoA/ROCK pathways in macrophages. The scaffold induces excellent bone regeneration in periodontal bone defects of diabetic rats because of the synergistic effects of good conductive, ROS-scavenging, anti-inflammatory, and immunomodulatory abilities. This study provides fundamental insights into the synergistical effects of conductivity, osteoinductivity, and immunomodulatory abilities on bone regeneration and offers a novel strategy to design immunomodulatory biomaterials for treatment of immune-related diseases and tissue regeneration.

Conductive polymers (CPs) are generally insoluble, and developing hydrophilic CPs is significant to broaden the applications of CPs. In this work, a mussel-inspired strategy was proposed to construct hydrophilic CP nanoparticles (CP NPs), while endowing the CP NPs with redox activity and biocompatibility. This is a universal strategy applicable for a series of CPs, including polyaniline, polypyrrole, and poly(3,4-ethylenedioxythiophene). The catechol/quinone contained sulfonated lignin (LS) was doped into various CPs to form CP/LS NPs with hydrophilicity, conductivity, and redox activity. These CP/LS NPs were used as versatile nanofillers to prepare the conductive hydrogels with long-term adhesiveness. The CP/LS NPs-incorporated hydrogels have a good conductivity because of the uniform distribution of the hydrophilic NPs in the hydrogel network, forming a well-connected electric path. The hydrogel exhibits long-term adhesiveness, which is attributed to the mussel-inspired dynamic redox balance of catechol/quinone groups on the CP/LS NPs. This conductive and adhesive hydrogel shows good electroactivity and biocompatibility and therefore has broad applications in electrostimulation of tissue regeneration and implantable bioelectronics.

Repairing osteochondral defects is a considerable challenge because it involves the breakdown of articular cartilage and underlying bone. Traditional hydrogels with a homogenized single‐layer structure cannot fully restore the function of osteochondral cartilage tissue. In this study, a mussel‐inspired hydrogel with a bilayer structure is developed to repair osteochondral defects. The hydrogel is synthesized by simultaneously polymerizing two layers using a one‐pot method. The resulting upper and lower gelatin methacryloyl‐polydopamine hydrogel layers are used as cartilage and subchondral bone repair layers, respectively. Polydopamine‐induced hydroxyapatite in situ mineralization takes place in the lower layer to mimic the structure of subchondral bone. The bilayer hydrogel exhibits good mechanical properties for the synergistic effect of covalent and noncovalent bonds, as well as nanoreinforcement of mineralized hydroxyapatite. To improve the tissue‐inducibility of hydrogels, transforming growth factor β3is immobilized in the upper layer to induce cartilage regeneration, while bone morphogenetic protein 2 is immobilized in the lower layer to induce bone regeneration. Bone and cartilage repair performance of the hydrogel is examined by implantation into a full‐thickness cartilage defect of a rabbit knee joint. The bilayer‐structure hydrogel promotes regeneration of osteochondral tissue, thus providing a new option for repair of osteochondral defects. A mussel‐inspired hydrogel with a bilayer structure is prepared to repair osteochondral defects. The upper layer is gelatin methacryloyl‐polydopamine hydrogel, which induces cartilage repair. In the lower layer, polydopamine regulates hydroxyapatite in situ mineralization, which induces subchondral bone repair. The bilayer‐structure hydrogel promotes regeneration of osteochondral tissue.

Electrical therapy has attracted significant attention because it can modulate cell behaviors and accelerate tissue repair. However, the effectiveness of electrical therapy is limited. This work develops electroresponsive and conductive polydopamine-polypyrrole microcapsules (PDA-PPy-MCs) on titanium surfaces using electrochemical deposition. During the electrochemical process, PDA and dexamethasone (DEX) as the anion are doped into a PPy backbone to neutralize its positive charge. PDA-PPy-MCs possess the cell affinity of PDA, the microstructure of MCs and the electroresponsive capability of PPy. The incorporation of PDA promotes the conductivity and adhesive strength of PPy. PDA-PPy-MCs can respond to electrical signals to release DEX on demand because of the redox behavior of PPy. The microstructure and PDA improve the drug-loading capability of PDA-PPy-MCs. A high-throughput bone marrow stromal cell (BMSC) culture system is designed to study the synergistic effects of composition, microstructure and electrical stimulation on cell behavior. The results indicate that PDA and the microporous structure not only enhance the biocompatibility of PDA-PPy-MC but also strengthen the effect of electrical stimulation. In vivo implantation shows that PDA-PPy-MCs have good biocompatibility. The high cell affinity, microstructure, conductivity and ability to control drug delivery using electrical signals make PDA-PPy-MCs a promising candidate for an on-demand drug delivery and electrical therapy system.