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Hydrogels hold great promise in the field of flexible electronics. Attempts in this area tend to the microstructure design of hydrogels, giving them specific adhesion and multi‐sensing functions. Here, a novel phase separation‐derived anisotropic adhesive structural color hydrogel film is presented for visually flexible electronics. The hydrogel film is generated by template replicating colloidal crystal by using phase separation emulsions of hydrophilic monomer (acrylic acid, AA), hydrophobic monomer (lauryl methacrylate, LMA), co‐monomer ([2‐(methacryloyloxy) ethyl] dimethyl‐(3‐sulfopropyl) ammonium hydroxide (SBMA)), surfactants (hexadecyl trimethyl ammonium bromide, CTAB) and initiator (ammonium persulphate (APS)). The appearance of phase separation results in asymmetric morphologies of hydrogel film, imparting them with anisotropic adhesive performance. Attributed to the formation of inverse opal scaffold structure, the hydrogel film is featured with vivid structural color, showing superior capability in self‐reporting mechanical behavior. Additionally, benefitting from the presence of abundant ions, the hydrogel film exhibits great conductivity. Thus, the resultant hydrogel film is demonstrated with stable dual‐signal sensing properties involving color‐changing and conductivity feedback ability to respond to human activities. These features make the proposed anisotropic adhesive structural color hydrogel film highly potential in the flexible electronic field. [ABSTRACT FROM AUTHOR]

Bioartificial livers have showcased significant value in the treatment of acute liver failure (ALF). Current efforts are directed toward overcoming challenges in the development of microcarriers, with a specific emphasis on integrating higher‐density liver cells to enhance detoxification capabilities. Here, inspired by the radial filtration model in hepatic lobules, ion‐specific silk fibroin microcarriers are proposed with biomimetic niches for cultivating functional liver cells at high density. These biomimetic microcarriers are generated by capillary microfluidic device with controllable adjustments of ion type or concentration within the aqueous phase. When cultivating human induced pluripotent stem cell ‐differentiated mature liver cells on these recrystallized microcarriers, notably enhanced cell proliferation activity, as well as increased metabolic and secretory functionality is observed. Based on these features, the microcarrier‐integrated bioreactor can effectively reduce hepatic transaminase levels and significantly improve urea, albumin production, and survival rate in rabbit ALF models is demonstrated. Thus, it is believed that the biomimetic microcarriers and their derived bioreactor may hold potential for clinical applications in managing ALF and other liver diseases. [ABSTRACT FROM AUTHOR]

Osteoarthritis has been regarded as a complex and serious degenerative disease. Attempts in this area are focused on improving the curative effect of stem cell‐based therapies. In this work, we present a novel inverse opal microcarriers‐based cytokines delivery system to induce autologous stem cell homing for osteoarthritis treatment. Considering their important role in stem cell recruitment and chondrogenic differentiation respectively, platelet‐derived growth factor BB (PDGF‐BB) and transforming growth factor β3 (TGF‐β3) are loaded into inverse opal microcarriers as model cytokines. Since cytokine release induces the corresponding variations in characteristic reflection spectra and structural colors, the inverse opal microcarriers possess the optical self‐reporting capacity to monitor the release process. In vitro cell experiments reveal that inverse opal microcarriers could successfully recruit the gathering of mesenchymal stem cells through the release of loaded cytokines. Based on these features, we have demonstrated the enhanced therapeutic effect of PDGF‐BB and TGF‐β3 loaded inverse opal microcarriers in the treatment of rat osteoarthritis models. These results indicate that the multifunctional inverse opal microcarriers‐based cytokines delivery system would find broad prospects in osteoarthritis treatment and other biomedical fields. [ABSTRACT FROM AUTHOR]

Diabetic wound healing is a serious, complex, and chronic process; one current promising and focusing technology in this area is stem cell treatment. Here, novel porous microneedle (MN) arrays is fabricated, which can highly mimetic stem cell niches, through template filling, and particle etching method. The human adipose‐derived stem cells (ADSCs) are encapsulated in Matrigel then loaded into the porous MN arrays by post‐perfusion. Because of the extracellular matrix‐mimicking, the biocompatible Matrigel offers a bionic microenvironment of stem cell nest suitable for growth. Benefiting from the numerous pore structures of MNs, the loaded ADSCs have enough space to fully absorb nutrients, proliferate greatly and exhibit prompted function. In addition, the cell‐loaded MN arrays have enough mechanical strength to penetrate the skin, allowing the ADSCs to get into the deep wound areas. Based on these features, the performance of the resultant MN arrays in promoting tissue regeneration is demonstrated, collagen deposition and angiogenesis in diabetes wounds of rat models. Thus, it is believe that the bioinspired porous MNs can act as excellent stem cell scaffolds and will find many practical values in clinic wound healing. [ABSTRACT FROM AUTHOR]

Localized chemotherapy is emerging as a potential strategy for cancer treatment due to its low systemic toxicity. However, the immune evasion of tumor cells and the lack of an intelligent design of the delivery system limit its clinical application. Herein, photothermal responsive microcarriers are designed by microfluidic electrospray for colorectal tumor treatment. The microcarriers loaded with Cangrelor, 5‐FU and MXene (G‐M@F/C+NIR) show sustained delivery of antiplatelet drug Cangrelor, thus inhibiting the activity of platelets, interactions of platelet‐tumor cell, as well as the tumor cells invasion and epithelial‐mesenchymal transition (EMT). In addition, the sustained delivery of chemotherapeutics 5‐FU and the photothermal effect provided by MXene enable the microcarriers to inhibit tumor cells proliferation and migration. In vivo studies validate that the G‐M@F/C+NIR microcarriers significantly inhibites tumor growth, decreased the expression of Ki‐67 in tumor cells and vascular endothelial growth factor (VEGF) in the tumor microenvironment, while increased the expression of E‐cadherin. It is believe that by means of the proposed photothermal responsive microcarriers, the synergistic strategy of platelet inhibition, chemotherapy, and photothermal therapy can find practical applications in cancer treatment. [ABSTRACT FROM AUTHOR]

Anticoagulation is vital to maintain blood fluidic status and physiological functions in the field of clinical blood‐related procedures. Here, novel biomimetic anticoagulated porous inverse opal hydrogel particles is presented as anticoagulant bearing dynamic screening capability. The inverse opal hydrogel particles possess abundant sulfonic and carboxyl groups, which serve as binding sites with multiple coagulation factors and inhibit the blood coagulation process. Owing to the variations of refractive index and pore sizes during the binding process, the particles appeared corresponding structure color variations, which can be adopted as sensory index of anticoagulation. Based on these features, a sensor containing these diverse structure color particle units is constructed for pattern recognition of coagulation factors level in clinical plasma samples. By analyzing the sensory information of the unit, the colorimetric "fingerprint" for each target can be obtained and summarized as a database. Besides, a portable test‐strip integrating sensory units is developed to distinguish the sample regarding abnormal coagulation factors‐derived diseases via multivariate data analysis. It is believed that such biomimetic anticoagulated structural color particles and their derived sensor will open new avenue for clinical detection and disease diagnosis. [ABSTRACT FROM AUTHOR]

Biomedical patches offer significant potential for keratitis treatment. Building on advances in multifunctionality and biomimicry, an innovative, multifunctional hydrogel patch with high therapeutic efficacy, inspired by the native architecture and functions of the cornea, is introduced. By engineering a composite patch comprising recombinant human collagen (RHC) hydrogel, near‐field electrospinning (NFES) microfibers, and gold‐nanoparticle‐decorated tetragonal barium titanates (BTO@Au), structural mimicry, mechanical reinforcement, tissue‐specific adhesion, and bacterial inhibition are achieved. The RHC hydrogel recreates a three‐dimensional (3D) microenvironment that emulates the natural structure of the corneal tissue, demonstrating excellent tissue adhesion. Integrated within this hydrogel, the NFES microfibers, designed to emulate the orthogonal arrangement of native corneal stroma, not only reinforce the mechanical strength of the RHC hydrogel but also act as scaffolds to guide the aligned growth of human keratocytes. A unique aspect of this advanced patch is the incorporation of BTO@Au nanoparticles, which generate reactive oxygen species for effective bacterial eradication when subjected to ultrasound stimulation. Through in vivo studies on rat models with infected corneal wounds, this hydrogel patch exhibits superior therapeutic efficacy compared to the current treatment. It is posited that these cornea‐inspired ultrasound‐responsive adhesive hydrogel patches represent a significant scientific advancement with high potential for clinical applications. [ABSTRACT FROM AUTHOR]

Human organoid models potentially offer a physiologically relevant platform to replace traditional monolayer cultures and animal models. In particular, the rapid development of engineered strategies including microfluidics, hydrogel, 3D printing and others, which have enormous advantages in comparison to conventional methods, is expected to further advance organoid technology. Up to now, many studies have demonstrated the engineered organoid models with complex cell composition, controlled structure, enhanced maturation, reduced heterogeneity, and so on. These engineered organoids are high promising for studies in development, disease, tissue repair, precision medicine and drug screening. In this review, a comprehensive summary of the engineered organoid model systems is provided based on microfluidics, hydrogel, 3D printing and so on. Then, the biomedical applications of these models are highlighted, which have displayed the great power in organoid field. Finally, the key bottlenecks and future development of organoid models are discussed about from an engineering perspective. [ABSTRACT FROM AUTHOR]

Many hydrogel patches are developed to solve the pervasive and severe challenge of complex wound healing, while most of them still lack satisfactory controllability and comprehensive functionality. Herein, inspired by multiple creatures, including octopuses and snails, a novel muti‐functional hydrogel patch is presented with controlled adhesion, antibacterial, drug release features, and multiple monitoring functions for intelligent wound healing management. The patch with micro suction‐cup actuator array and a tensile backing layer is composed of tannin grafted gelatin, Ag‐tannin nanoparticles, polyacrylamide (PAAm) and poly(N‐isopropylacrylamide) (PNIPAm). In virtue of the photothermal gel‐sol transition of tannin grafted gelatin and Ag‐tannin nanoparticles, the patches exert a dual anti‐microbial effect and temperature‐sensitive snail mucus‐like features. In addition, as the "suction‐cups" consisting of thermal responsive PNIPAm can undergo a contract‐relax transformation, the medical patches can adhere to the objects reversibly and responsively, and release their loaded vascular endothelial growth factor (VEGF) controllably for wound healing. More attractively, benefiting from their fatigue resistance, self‐healing ability of the tensile double network hydrogel, and electrical conductivity of Ag‐tannin nanoparticles, the proposed patches can report multiple wound physiology parameters sensitively and continuously. Thus, it is believed that this multi‐bioinspired patch has immense potential for future wound healing management. [ABSTRACT FROM AUTHOR]

Hydrogel patches have outstanding values in wound treatment; challenges in this field are concentrated on developing functional and intelligent hydrogel patches with new antibacterial strategies for improving healing process. Herein, a novel melanin‐integrated structural color hybrid hydrogel patches for wound healing is presented. Such hybrid hydrogel patches are fabricated by infusing asiatic acid (AA)‐loaded low melting‐point agarose (AG) pregel into the melanin nanoparticles (MNPs)‐integrated fish gelatin inverse opal film. In this system, MNPs not only impart the hybrid hydrogels with properties of photothermal antibacterial and antioxidant, but also improve the visibility of structural colors by providing an inherent dark background. Besides, the photothermal effect of MNPs under near‐infrared irradiation can also trigger liquid transformation of AG component in hybrid patch, resulting in the controllable release of its loaded proangiogenic AA. Attracting, this drug release induced refractive index variations in the patch can be detected as visible structural color shifting, which can be used to monitor their delivery processes. Benefiting from these features, the hybrid hydrogel patches are demonstrated to achieve excellent therapeutic effects for in vivo wound treatment. Thus, it is believed that the proposed melanin‐integrated structural color hybrid hydrogels are valuable as multifunctional patches for clinical applications. [ABSTRACT FROM AUTHOR]

Fibrous scaffolds have shown their advantages in tissue engineering, such as peripheral nerve regeneration, while most of the existing fiber‐shaped scaffolds are with simple structures, and the in vitro performance for nerve regeneration lacks systematic analysis. Here, novel nerve‐on‐a‐chip derived biomimicking microfibers for peripheral nerve regeneration are presented. The microfibers with controllable core–shell structures and functionalities are generated through capillary microfluidic devices. By integrating these microfibers into a multitrack‐architectured chip, and coculturing them with nerve cells as well as gradient bioactive elements, the nerve‐on‐a‐chip with the capabilities of systematically assessing the performances of nerve fiber formation in the hollow microfibers at in vitro level is constructed. Based on a rat sciatic nerve injury model, the rapid promotion ability is demonstrated of optimized microfibers in nerve regeneration and function recovery in vivo, which implies the credibility of the nerve‐on‐a‐chip on biomimicking microfibers evaluation for peripheral nerve regeneration. Thus, it is convinced that the organ‐on‐a‐chip will undoubtedly open up a new chapter in evaluating biological scaffolds for in vivo tissue engineering. [ABSTRACT FROM AUTHOR]

Hard‐healing diabetic wound brings burgeoning physical and mental burdens to patients. Current treatment strategies tend to achieve multistage promotion and real‐time reporting to facilitate wound management. Herein, a biomimetic enzyme cascade inverse opal microparticles system for wound healing, which is intergated with glucose oxidase (GOD) and copper peroxide (CP). Such microparticles are composed of biofriendly hyaluronic acid methacryloyl (HAMA) and pH‐responsive acrylic acid (AA), which provided abundant binding sites and spaces for chemical immobilizing and physical doping of enzymes and metal bioinorganics. When the cascade catalytic system is applied on wound sites, hyperglycemia environment would serve as a hydrogen peroxide (H2O2) generator through GOD catalysis, while acidic environment triggers the decomposition of CP, further catalyzing H2O2 to generate reactive oxygen species (ROS). Additionally, the distinctive structural color of the microparticles can visually reflect the wound pH and intelligently estimate the healing state. It is demonstrated that such microparticle systems exhibit excellent broad‐spectrum antibacterial and angiogenesis‐promoting properties, as well as significant real‐time reporting ability for wound healing. These features indicate that enzyme cascade structural color microparticles possess valuable potential in wound healing and related field. [ABSTRACT FROM AUTHOR]

Chemotherapy is an essential postoperative treatment for pancreatic cancer, while due to the lack of effective drug evaluation platforms, the therapeutic outcomes are hampered by tumor heterogeneity among individuals. Here, a novel microfluidic encapsulated and integrated primary pancreatic cancer cells platform is proposed for biomimetic tumor 3D cultivation and clinical drug evaluation. These primary cells are encapsulated into hydrogel microcapsules of carboxymethyl cellulose cores and alginate shells based on a microfluidic electrospray technique. Benefiting from the good monodispersity, stability, and precise dimensional controllability of the technology, the encapsulated cells can proliferate rapidly and spontaneously form 3D tumor spheroids with highly uniform size and good cell viability. By integrating these encapsulated tumor spheroids into a microfluidic chip with concentration gradient channels and culture chambers, dynamic and high‐throughput drug evaluation of different chemotherapy regimens could be realized. It is demonstrated that different patient‐derived tumor spheroids show different drug sensitivity on‐chip, which is significantly consistent with the clinical follow‐up study after the operation. The results demonstrate that the microfluidic encapsulated and integrated tumor spheroids platform has great application potential in clinical drug evaluation. [ABSTRACT FROM AUTHOR]

Due to their intrinsic anti‐inflammatory and immunomodulatory properties, adipose‐derived stem cells (ADSCs) are explored as a promising alternative in treating rheumatoid arthritis (RA). To address the poor survival and function loss of directly injected stem cells, efforts in this area are focus on the generation of efficient cell delivery vehicles. Herein, a novel extracellular matrix (ECM)‐inspired injectable hydrogel for ADSCs encapsulation and RA treatment is proposed. The hydrogel with dendritic polylysine and polysaccharide components is formed through the reversible Schiff base crosslinking. It possesses self‐healing capability, superior mechanical properties, minimal toxicity, and immunomodulatory ability. When encapsulated with ADSCs, the hydrogel could recover chronic inflammation by directly reversing the dominant macrophage phenotype from M1 to M2 and inhibiting the migration of fibroblast‐like synoviocytes. Through a collagen‐induced arthritis rat model, the tremendous therapeutic outcomes of this ADSCs‐laden hydrogel, including inflammation attenuation, cartilage protection, and bone mineral density promotion are demonstrated. These results make the ECM‐inspired hydrogel laden with ADSCs an ideal candidate for treating RA and other autoimmune disorders. [ABSTRACT FROM AUTHOR]

Erythrocytes are the most abundant cells in the blood. As the results of long‐term natural selection, their specific biconcave discoid morphology and cellular composition are responsible for gaining excellent biological performance. Inspired by the intrinsic features of erythrocytes, various artificial biomaterials emerge and find broad prospects in biomedical applications such as therapeutic delivery, bioimaging, and tissue engineering. Here, a comprehensive review from the fabrication to the applications of erythrocyte‐inspired functional materials is given. After summarizing the biomaterials mimicking the biological functions of erythrocytes, the synthesis strategies of particles with erythrocyte‐inspired morphologies are presented. The emphasis is on practical biomedical applications of these bioinspired functional materials. The perspectives for the future possibilities of the advanced erythrocyte‐inspired biomaterials are also discussed. It is hoped that the summary of existing studies can inspire researchers to develop novel biomaterials; thus, accelerating the progress of these biomaterials toward clinical biomedical applications. [ABSTRACT FROM AUTHOR]

Heart‐on‐a‐chip plays an important role in revealing the biological mechanism and developing new drugs for cardiomyopathy. Tremendous efforts have been devoted to developing heart‐on‐a‐chip systems featuring simplified fabrication, accurate imitation and microphysiological visuality. In this paper, the authors present a novel electroconductive and anisotropic structural color hydrogel by simply polymerizing non‐close‐packed colloidal arrays on super aligned carbon nanotube sheets (SACNTs) for visualized and accurate heart‐on‐a‐chip construction. The generated anisotropic hydrogel consists of a colloidal array‐locked hydrogel layer with brilliant structural color on one surface and a conductive methacrylated gelatin (GelMA)/SACNTs film on the other surface. It is demonstrated that the anisotropic morphology of the SACNTs could effectively induce the alignment of cardiomyocytes, and the conductivity of SACNTs could contribute to the synchronous beating of cardiomyocytes. Such consistent beating rhythm caused the deformation of the hydrogel substrates and dynamic shifts in structural color and reflection spectra of the whole hybrid hydrogels. More attractively, with the integration of such cardiomyocyte‐driven living structural color hydrogels and microfluidics, a visualized heart‐on‐a‐chip system with more consistent beating frequency has been established for dynamic cardiomyocyte sensing and drug screening. The results indicate that the electroconductive and anisotropic structural color hydrogels are potential for various biomedical applications. [ABSTRACT FROM AUTHOR]

Wound dressing with the capacities of antioxidation, antiinflammation, and efficient angiogenesis induction is expected for effectively promoting wound healing. Herein, a novel core‐shell hyaluronic acid (HA) microneedle (MN) patch with ferrum‐mesenchymal stem cell‐derived artificial nanovesicles (Fe‐MSC‐NVs) and polydopamine nanoparticles (PDA NPs) encapsulated in the needle tips is presented for wound healing. Fe‐MSC‐NVs containing multifunctional therapeutic cytokines are encapsulated in the inner HA core of the MN tips for accelerating angiogenesis. The PDA NPs are encapsulated in the outer methacrylated hyaluronic acid (HAMA) shell of the MN tips to overcome the adverse impacts from reactive oxygen species (ROS)‐derived oxidative stress. With the gradual degradation of HAMA patch tips in the skin, the PDA NPs are sustainably released at the lesion to suppress the ROS‐induced inflammation reaction, while the Fe‐MSC‐NVs significantly increase the migration, proliferation, and tube formation of human umbilical vein endothelial cells (HUVEC). More attractively, the combination of PDA NPs and Fe‐MSC‐NVs further promotes M2 macrophage polarization, thereby suppressing wound inflammation. Through in vivo experiment, the Fe‐MSC‐NVs/PDA MN patch shows an excellent effect for diabetic wound healing. These features of antioxidation, antiinflammation, and pro‐angiogenesis indicate the proposed composite core‐shell MN patch is valuable for clinical wound healing applications. [ABSTRACT FROM AUTHOR]

Micromotors have opened novel avenues for drug delivery due to their capacity for self‐propelling. Attempts in this field trend towards ameliorating their functions to promote their clinical applications. In this paper, an ingenious suction‐cup‐inspired micromotor is presented with adhesive properties for drug delivery in the stomach. The micromotors are fabricated by using hydrogel replicating the structure of suction‐cup‐like microparticles, which derive from self‐assembly of colloidal crystals under rapid solvent extraction, followed by loading magnesium (Mg) in the bottom spherical surface. The Mg‐loaded micromotors can realize spontaneous movement due to the continual generation of hydrogen bubbles in gastric juice. The combination of unique suction‐cup‐like structure with excellent motion performance makes the micromotor an ideal carrier for drug delivery as they can efficiently adhere to the tissue. Moreover, benefiting from the porous structure, the hydrogel micromotors exhibit a high volume‐surface ratio, which enables efficient drug loading. It is demonstrated that the suction‐cup‐inspired micromotors can adhere efficiently to the ulcer‐region in the stomach and release drugs due to their distinctive architecture and spontaneous motion, exhibiting desirable curative effect of gastric ulcer. Thus, the suction‐cup‐inspired micromotors with adhesive properties are expected to advance the development of micromotor in clinical applications. [ABSTRACT FROM AUTHOR]

Electronic skins have received increasing attention in biomedical areas. Current efforts about electronic skins are focused on the development of multifunctional materials to improve their performance. Here, the authors propose a novel natural‐synthetic polymers composite structural color hydrogel film with high stretchability, flexibility, conductivity, and superior self‐reporting ability to construct ideal multiple‐signal bionic electronic skins. The composite hydrogel film is prepared by using the mixture of polyacrylamide (PAM), silk fibroin (SF), poly(3,4‐ethylenedioxythiophene):poly (4‐styrene sulfonate) (PEDOT:PSS, PP), and graphene oxide (GO) to replicate colloidal crystal templates and construct inverse opal scaffolds, followed by subsequent acid treatment. Due to these specific structures and components, the resultant film is imparted with vivid structural color and high conductivity while retaining the composite hydrogel's original stretchability and flexibility. The authors demonstrate that the composite hydrogel film has obvious color variation and electromechanical properties during the stretching and bending process, which could thus be utilized as a multi‐signal response electronic skin to realize real‐time color sensing and electrical response during human motions. These features indicate that the proposed composite structural color hydrogel film can widen the practical value of bionic electronic skins. [ABSTRACT FROM AUTHOR]

Microneedles are regarded as an emerging and promising transdermal drug delivery strategy. Great efforts are devoted to getting rid of their material restrictions and imparting them with abilities to carry various drugs. Here, inspired by ice formation in nature and based on characteristics of different frozen materials, the authors present novel ice microneedles made from versatile soft materials using a simple freezing template‐based fabrication stratagem for effective transdermal delivery of diverse actives. Their strategy can convert microneedles with almost all water‐containing components from softness into hardness for guaranteeing satisfactory penetration, thus removing their material component limitations. As all fabrication procedures are mild and actives can maintain activity during these processes, the ice microneedles can carry and deliver various actives from small molecules and macromolecules to even living organisms. They have demonstrated that these ice microneedles can easily penetrate mouse and swine skins using a microneedle injector, with their active‐carried tips left inside after their ice base melts. Thus, by loading heparin, erythropoietin, or biosafe Bacillus subtilis (B. subtilis) inside the ice microneedles to treat mouse models, the practical values of these microneedles are well displayed, indicating their bright prospects in universal drug delivery systems. [ABSTRACT FROM AUTHOR]

As a common chronic inflammatory skin disease, atopic dermatitis (AD) troubles many people, while its effective therapy is a challenge. Here, we present novel polydopamine (PDA) nanoenzyme integrated near-infrared ray (NIR)-responsive microneedles (MNs) with antioxidant capacity for AD treatment. Such MNs are composed of a hyaluronic acid (HA) backing layer and hyaluronic acid methacrylate (HAMA) tips that are loaded with PDA nanoenzyme. Owing to the photo-thermal conversion capability of PDA nanoenzyme, the MNs can enhance local microcirculatory blood flow, inhibit bacterial growth, and consequently alleviate inflammation and facilitate lesion repair. Besides, the antioxidant properties of PDA nanoparticles could markedly reduce the ROS production in HaCaT cells under conditions of elevated oxidative stress. Based on these features, we have demonstrated that the MNs could effectively realize remission in AD mouse models. Thus, we believe that the proposed NIR-responsive PDA nanoenzyme MNs could serve as a promising therapeutic approach for the treatment and management of clinic AD. [Display omitted] • Polydopamine nanoenzyme microneedles are developed for atopic dermatitis (AD) therapy. • The photo-responsive microneedles enhance microcirculation and inhibit bacteria. • Polydopamine nanoenzymes show ROS scavenge and cytoprotective capacities in AD. • Hyaluronic acid backing layer acts as skin barrier repairing emollient. • The PDA nanoenzyme microneedles decrease Th2 inflammation in the AD mouse model. [ABSTRACT FROM AUTHOR]

Wearable electronics that can convert various external stimuli into electrical signals hold great potential for diverse applications. Efforts in this area are focused on developing functional hydrogels to improve the values of these flexible electronics. Herein, we present a novel carbon nanotube (CNT)-based hydrogel with the synergistic features of good mechanical strength, high sensitivity, self-healing capability, and on-demand removability for wearable electronics. The hydrogel was fabricated by mixing dopamine-modified oxidized hyaluronic acid (OHA-DA), cyanoacetate group-functionalized dextran (DEX-CA), and carbon nanotubes (CNTs) in the presence of histidine. The catechol and aldehyde groups on OHA-DA impart the hydrogel with high tissue adhesiveness. Owing to the existence of CNTs, the hydrogel exhibited outstanding conductivity and could respond to different human motions and convert these stimuli as resistance signals. Notably, because of the photothermal conversion property of CNTs and thermally reversible performance of the generated C=C double bonds between aldehyde groups and cyanoacetate groups, the hydrogel was imparted with intriguing on-demand dissolution ability under near-infrared (NIR) irradiation and could be facilely removed from tissues whenever necessary. We believe that such hydrogel will open up new opportunities for the design and construction of next-generation wearable electronics. [Display omitted] • Conductive carbon nanotube (CNT) hydrogels with high sensitivity and on-demand dissolution ability were prepared. • The CNT hydrogel demonstrates the ability to detect various human motions and convert them into resistance signals. • By applying near-infrared irradiation, the hydrogel sensor can be facilely removed from tissues after use. • This research will facilitate novel applications of hydrogels in wearable electronic skin. [ABSTRACT FROM AUTHOR]

Microneedle patches (MNs) have demonstrated potentials in transdermal drug delivery for skin disease therapy. Effort is mainly focused on the improvement of MNs' materials, structures and functions to realize intelligent drug delivery. Here, we propose a novel black phosphorus (BP)-loaded hydrogel inverse opal MNs with photothermal responsive capacity and vivid structural color screening for psoriasis treatment. The MNs, composed of a BP-loaded N-isopropyl acrylamide (NIPAM)/poly(ethylene glycol) diacrylate (PEGDA) inverse opal hydrogel scaffold and the drug-carrying gelatin/agarose filler inside the scaffold pores, are fabricated through combined approaches of nanoparticle assembly, reversed-phase replication and micro-molding. Due to the photothermal conversion of BP, temperature-responsive shrinkage of NIPAM, and heat-sensitive gelatin, the resulting MNs obtain the ability of good hydrophobic drug loading and photothermal controllable drug release. In addition, profiting from the inverse opal structure with optical properties, the MNs exhibit a bright structural color and can generate characteristic wavelength shift during drug release, providing a real-time monitoring and feedback for drug delivery. Based on these features, the MNs show excellent in vivo drug administration and efficient psoriasis treatment in mice, indicating their potential as intelligent drug delivery vehicles for practical applications. [Display omitted] • Microneedle patches (MNs) have demonstrated potentials in transdermal drug delivery for skin disease therapy. • A novel black phosphorus (BP)-loaded hydrogel inverse opal MNs with photothermal responsive capacity and vivid structural color screening was proposed for psoriasis treatment. • Due to the photothermal conversion of BP, temperature-responsive shrinkage of NIPAM, and heat-sensitive gelatin, the resulting MNs obtain the ability of good hydrophobic drug loading and photothermal controllable drug release. • Profiting from the inverse opal structure with optical properties, the MNs exhibit a bright structural color and can generate characteristic wavelength shift during drug release, providing a real-time monitoring and feedback for drug delivery. • The MNs show excellent in vivo drug administration and efficient psoriasis treatment in mice, indicating their potential as intelligent drug delivery vehicles for practical applications. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Severe intrauterine adhesions (IUAs) have a great negative impact on women's psychological and reproductive health. It remains a significant challenge to prevent postoperative IUAs because of the complications of various clinical preventive measures and incompatibility of uterine cavity morphology. Herein, we present a new drug-loaded porous scaffold based on a microfluidic droplet template, which combines the characteristics of the artificial biocompatible material GelMA and the natural polysaccharide material Na-alginate. By changing the containers that collect the microfluidic droplets, the porous scaffold conforming to the shape of the uterine cavity could be obtained. The porous structure, mechanical property, and flexibility impart the scaffold with compressibility and send it to the uterus through the vagina. In addition, the external–internal connected open structures could load and control the release of drugs to repair the damaged region continuously in vivo. To verify the antiadhesion and repair of drug-loaded porous scaffolds, we tested the system in the rat model of IUAs, and it was demonstrated that the system had the ability to improve neovascularization, cellularize the damaged tissue, and repair the endometrium. These features provide the drug-loaded porous scaffolds with new options for the improvement of postoperative IUAs. Statement of Significance Intrauterine adhesions are caused by various causes of damage to the endometrial basal layer, thus leading to part or entire adhesions in the cervical or uterine cavity. Clinically, various preventive measures reach the barrier effect through the physical barrier, which are difficult to further promote the repair of the damaged endometrium, and most of them have apparent side effects. This study aims to prepare compressible and biodegradable three-dimensional porous drug-loading biological scaffolds. GelMA and Na-alginate have desirable biocompatibility. The interconnect porous scaffolds, which were prepared through the combination of biomaterials and single emulsion microfluidics, not only have compressibility but also provide space for drug delivery and release. This system can further promote the repair of the endometrium while preventing adhesion. [ABSTRACT FROM AUTHOR]

Developing a potential alternative with safe, minimally invasive, and highly effective antimicrobial properties is significant for treating bacterial keratitis. In this paper, we present novel nanozyme-loaded frozen reinforced microneedles (FR-MNs) with the ability to deliver the nanozyme controllably inside the cornea to treat keratitis. The nanozymes constructed by the iron ion, tannic acid (TA), and poly (vinylpyrrolidone; PVP) (FeTAP) are incorporated within the MNs tips. The freezing process could greatly enhance the mechanical strength of the tips. Taking advantage of the pH-dependent peroxidase-mimetic activities of FeTAP, the FeTAP integrated MNs can catalyze hydrogen peroxide (H 2 O 2) to produce much more oxidative hydroxyl (•OH) in acidic condition to kill bacteria. Meanwhile, the excellent photothermal efficiency of FeTAP can further enhance the ability of bacterial killing under near-infrared (NIR) irradiation. In addition, the photothermal action can rapidly increase the temperature of the frozen microneedles and subsequently soften the MNs after penetration, which can result in better adaptation of MNs to soft tissues. Based on the nanozyme-loaded FR-MNs, we have demonstrated that this formulation exhibited superior therapeutic potential in the rat eye infection model compared with conventional eye drops. These features impart the proposed nanozyme-loaded FR-MNs with great scientific value and promising clinical applications. [Display omitted] • A frozen reinforced microneedles (FR-MNs) based on recombinant human collagen was fabricate. • The peroxidase-like and photothermal performance of the nanozyme endowed the MNs with superior antibacterial ability. • The proposed nanozyme-loaded FR-MNs exhibited superior therapeutic potential in the rat eye infection model. [ABSTRACT FROM AUTHOR]

This review focus on the current advances of freezing-derived functional materials, involving the design rationale (freezing stratagems and curing methods) of material fabrication and various applications, including mechanical, thermal, energy, environmental, and biomedical applications. The emphasis is put on the correlations among multiscale structures, extraordinary properties and multifarious applications. Promising research directions and challenges about the freezing processing tools are also presented. [Display omitted] Ice-templating, also known as freeze-casting, has emerged as a novel and versatile processing technology in various applications such as strong and tough structured materials, thermal management, energy storage and conversion, biomedical engineering, and so on. By replicating the fractal ice crystal structure, both multiscale hierarchical architectures (from macroscale to micrometer-, and nanometer-scales) and corresponding unique structure-derived functions can be achieved. This review focus on the current advances of freezing-derived functional materials, involving the design rationale (freezing strategies and curing methods) of material fabrication and various applications, including mechanical, thermal, energy, environmental, and biomedical applications. Opportunities (promising research directions and new application scenarios) and challenges about the ice-templating tools are also presented. [ABSTRACT FROM AUTHOR]

[Display omitted] Heart-on-chips have emerged as a powerful tool to promote the paradigm innovation in cardiac pathological research and drug development. Attempts are focused on improving microphysiological visuals, enhancing bionic characteristics, as well as expanding their biomedical applications. Herein, inspired by the bright feathers of peacock, we present a novel optical and electrical dual-responsive heart-on-a-chip based on cardiomyocytes hybrid bright MXene structural color hydrogels for hormone toxicity evaluation. Such hydrogels with inverse opal nanostructure are generated by using pregel to replicate MXene-decorated colloidal photonic crystal (PhC) array templates. The attendant MXene in the hydrogels could not only enhance the saturation of structural color, but also ensure the composite hydrogel with excellent electroconductivity to facilitate the synergetic beating of their surface cultured cardiomyocytes. In this case, the hydrogels would undergo a synchronous deformation and generate shift in corresponding photonic band gap and structural color, which could be employed as visual signal for self-reporting of the cardiomyocyte mechanics. Based on these features, we demonstrated the practical value of the optical and electrical dual-responsive structural color MXene hydrogels constructed heart-on-a-chip in hormone toxicity testing. These results indicated that the proposed heart-on-a-chip might find broad prospects in drug screening, biological research, and so on. [ABSTRACT FROM AUTHOR]

• By introducing air bubbles into microfluidic channels, the length of microfiber fragments can easily be adjusted through flow rate of inner phase (air). • With encapsulation of borax and gelatin, hydrogel microfiber fragments exhibited good biocompatibility and self-healing property, making them desirable carriers for BMSCs. • Our dressing materials are with multi-components, elaborated structure for cell proliferation, and favorable porosity for material exchange of stem cells. Mesenchymal stem cells (MSCs) loaded hydrogels have shown positive therapeutic effects in skin wound treatment, while their application is still impractical on the wound bed. Here, we propose novel MSCs-loaded self-healing hydrogel microfiber fragments from microfluidic bubbles interrupted spinning for wound healing. The hydrogel microfibers are composed of sodium alginate, gelatin, polyvinyl alcohol, and borax, vesting them with good biocompatibility and self-healing ability. Their fragments with adjustable length are generated by introducing bubbles into microfluidic channels. We have demonstrated that the self-healing microfibers can promote the proliferation of MSCs, which are seeded alongside fragments' surfaces to further facilitate the wound healing process. In addition, these MSCs laden self-healing hydrogel microfibers (MSG-fibers) showed obvious healing effect in rat wound model, which significantly promoted granulation tissue formation, collagen deposition and vascular construction at the wound site. Thus, we believe that our proposed MSC-laden microfiber fragments are valuable in promoting wound healing and have promising prospect in becoming new options for wound management. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dual-functional core–shell microneedle patches are successfully fabricated from gelatin methyl methacrylate (GelMA) and hyaluronic acid (HA). • A two-layer drug delivery system is developed for the treatment of oral ulcers, with excellent mechanical ability and sustained release ability. • Dual-functional core–shell microneedle patches promoted wound healing and reduced inflammation in the oral ulcer model. Microneedle patches have been widely used in transdermal drug delivery due to their painless and enhanced drug delivery. Despite their established success, their application within the oral cavity, characterized by a dense distribution of nociceptor, remains largely unexplored. Here, we introduce a well-designed dual-functional core–shell microneedle patches to address oral ulcers. The outer shell of the microneedle tips is crafted from hyaluronic acid (HA) and loaded with lidocaine, while the inner core, composed of gelatin methyl methacrylate (GelMA) encapsulates dexamethasone. The HA shell rapidly dissolves upon application, facilitating the immediate release of lidocaine to induce anesthesia at the ulcer site, thereby alleviating the associated painful sensations. Simultaneously, GelMA imparts mechanical strength and ensured the sustained release of dexamethasone. In vivo experiments further demonstrated that the Dex@MN group exhibiting the most rapid healing rate also displayed the highest levels of collagen deposition and the lowest concentrations of inflammatory factors. This collective evidence underscores the considerable potential of dual-functional core–shell microneedle patches in the treatment of oral diseases. [ABSTRACT FROM AUTHOR]

[Display omitted] Wound healing has invariably been a fundamental health concern, demanding manpower and materials and causing financial burdens. In this research, inspired by the hemostatic function of platelets, we proposed a novel bionic hydrogel by covalent amidation crosslinking natural platelet and alginate for wound healing. With the natural functional groups, the platelet-derived hydrogel exhibited outstanding biocompatibility and blood compatibility. By changing the addition ratio of platelets to alginates, the mechanical properties of the achieved hydrogel were variable to cater to different wound environments. Furthermore, silver nanoparticles could be loaded into the void space of the hydrogel which endowed the composites with superior anti-infective properties. We have demonstrated that the bio-inspired platelet hydrogel could promote hemostasis of acute tissue damage, prevent bacterial proliferation, and promote angiogenesis, collagen deposition, and granulation tissue formation in wound healing. These features signify the potential values of the bio-inspired platelet hydrogel in clinical applications. [ABSTRACT FROM AUTHOR]

• Composite hydrogel patches containing natural multi-actives (GP + PU@Gel) were synthesized. • GP + PU@Gel patches were formulated by incorporating freeze-dried grape peel, oligomeric proanthocyanidins (OPC), and puerarin through spontaneous physical crosslinking. • The GP + PU@Gel patches exhibited antibacterial, antioxidant, anti-inflammatory, and angiogenic properties. • GP + PU@Gel patches demonstrate promising prospects for the treatment of diabetic wounds. Biomedical patches have garnered recognition for their efficacy in diabetic wound management. Current research efforts are focused on developing natural and efficient hydrogel patches in order to reduce inherent side effects and enhance therapeutic outcomes. In this study, we present natural multi-actives composited hydrogel patches for diabetic wound management. The novel medical patch was fabricated using freeze-dried grape peel, oligomeric proanthocyanidins (OPC) and puerarin based on spontaneous physical crosslinking. With the incorporation of OPC, the natural patch exhibited favorable photothermal antibacterial properties, effectively inhibiting S. aureus and E. coli under 808 nm near-infrared irradiation. In addition, the grape peel could induce M2 macrophage polarization and scavenge reactive oxygen species, showcasing immunomodulatory effects. Moreover, the puerarin component in the patches was discovered to promote endothelial cell proliferation and migration, thereby facilitating angiogenesis in vitro. Based on these features, we have demonstrated the antibacterial, antioxidant, anti-inflammatory, and angiogenic effects of the patches in vivo. Thus, we believe that the natural multi-actives composite patch holds significant promise for diabetic wound treatment and broader biomedical applications. [ABSTRACT FROM AUTHOR]

• A Chinese herb hydrogel patch with bilayer structure is presented. • The patches realize programmed drug delivery efficacy and therapeutic effect. • The drug release condition is visually reflected by structural color change. • The patch could accelerate infected wound healing process. Chinese herb hydrogel has outstanding values in wound treatment. Tremendous effort is dedicated to developing functional and intelligent Chinese herb hydrogels for accelerating healing process. Herein, a novel multifunctional bilayer Chinese herb hydrogel patch for wound healing is presented. The patches are composed of a Ginsenoside compound K (GCK)-integrated chitosan inverse opal scaffold layer and a Bletilla striata polysaccharide (BP) hydrogel filler layer. As the photothermal conversion capacity of BP can trigger faster degradation of its hydrogel layer under near-infrared (NIR) light, the encapsulated BP can be controllably released to wound area and exhibit photothermal antibacterial and antioxidant effects. Besides, the inverse opal scaffold layer shows great mechanical property and moisturizing performance, and its released GCK can promote angiogenesis for long term therapeutic effects. Attractively, due to responsive structural color, the patch is endowed with self-reporting performance, which can real-time visually monitor the drug release degree. Taking advantages of these properties, the patches have been demonstrated to achieve satisfying therapeutic effects for in vivo wound treatment. Therefore, we believe that the proposed Chinese herb hydrogel patches are valuable as multifunctional patches for clinical treatment. [ABSTRACT FROM AUTHOR]

Recurrence of malignant tumor after surgical resection is the main reason of cancer treatment failure. Here, a novel kind of silk inverse opal particles (SIOPs) for post-surgical tumor treatment is presented, and it is derived from colloid crystal bead templates by negatively replicating. Because of their abundant uniform nanopores, interconnected nanochannels and excellent biocompatibility, SIOPs could not only carry great amount of anti-tumor drugs for tumor therapy, but also could provide support for cell adhesion, proliferation and differentiation as the 3D spherical scaffolds which is beneficial to the tissue repair at resection sites. It is demonstrated that the antibody drugs could maintain their high biological activity without any influences during the preparation of SIOPs and these particles were able to enhance the therapeutic efficacy and promote tissue regeneration after surgical resection with their multifunctional features. These prominent properties indicate the great potentials of SIOPs as a promising strategy for efficient postoperative cancer therapy. [ABSTRACT FROM AUTHOR]

In this work, we present a simple droplet microfluidic approach for generating graphene oxide (GO) hydrogel composite particles for oil decontamination. By stepwise solvent exchanges, the resulted hydrophilic GO hydrogel composite particles were transferred into organic media without any chemical modifications. As the GOs were locked tightly in hydrogel network, they were hardly changed during the processes of solvent exchanges. Thus, their polar surfaces remained in direct contact with the exchanged organic media, which indicated that the transferred GO particles were capable of effectively adsorbing polar impurities. Attractively, by encapsulating hollow cores and additional magnetic nanoparticles into the emulsion templates during the fabrication, the GO hydrogel composite particles were imparted with hierarchical porous structures and controllable movement capability, both of which could improve their efficiency of impurities adsorbing. These features make the GO hydrogel composite particles described here ideal for oil decontamination. [ABSTRACT FROM AUTHOR]

Barcodes-based suspension array have for demonstrated values in multiplex assay of tumor markers. Photonic barcodes which are encoded by their characteristic reflection peaks are the important supports for suspension array due to their stable code, low fluorescent background and high surface-volume ratio. Attempts to develop this technology tend to improve the function of the photonic barcodes. Here, we present a new type of hybrid hydrogel photonic barcodes for efficient multiplex assays. This photonic barcodes are hybrid inverse opal hydrogel composed of poly(ethylene glycol) diacrylate (PEG-DA) and agarose. The polymerized PEG-DA hydrogel could guarantee the stabilities of the inverse opal structure and its resultant code, while the agarose could offer active chemical groups for the probe immobilization and homogeneous water surrounding for the bioassay. In addition, the interconnected pores inverse opal structure could provide channels for biomolecules diffusing and reaction into the voids of barcodes. These features imparted the hybrid hydrogel photonic barcodes with limits of detection (LOD) of 0.78 ng/mL for carcinoembryonic antigen (CEA) and 0.21 ng/mL for α-fetoprotein (AFP), respectively. It was also demonstrated that the proposed barcodes showed acceptable accuracy and detection reproducibility, and the results were in acceptable agreement with those from common clinic method for the detections of practical clinical samples. Thus, our technique provides a new platform for simultaneous multiplex immunoassay. [ABSTRACT FROM AUTHOR]

• A multifunctional microneedle patch with aligned CNT sheet basement is presented. • The microneedle patch has photo-thermal and electro-thermal conversion capacity. • The microneedle patch could induce the orientation of fibroblasts. • The multifunctional patch loaded with VEGF could promote wound healing. Wound healing has become a health concern and economic burden worldwide for its high incidence and complexity. Attempts to improve wound treatment tend to develop biomedical patches with delicate structure design and functionality. In this paper, we present novel multifunctional microneedle patches with aligned carbon nanotube (CNT) sheet basement for promoting wound healing. Because of the outstanding biocompatibility, biodegradability and non-immunogenicity, hyaluronic acid (HA) is utilized to construct the CNT-integrated microneedle patch with vascular endothelial growth factor (VEGF) encapsulation. It was found that the aligned CNT layer basement could not only impart the composite microneedle patch with orientation morphology, but also endow the patch with controllable release performance, due to its photo-thermal or electro-thermal conversion capacity. Based on these features, we have demonstrated that the highly ordered microstructure of CNT could effectively induce the orientation of fibroblasts; while VEGF release could facilitate tubular formation of endothelial cells. Thus, the aligned CNT and VEGF-loaded multifunctional patch is beneficial to the wound repair process in a typical animal experiment. These results indicate that the proposed microneedle patch is potentially promising for regeneration medicine. [ABSTRACT FROM AUTHOR]

• Coordination polymer nanozymes show pH-dependent peroxidase-like property. • The FNDs achieve high antibacterial activity against E. coli , S. aureus and MRSA. • Developing a novel FNDs-integrated colorimetric microneedle patch. • The FNDs-MNs can recognize normal wounds and bacteria infected wounds. • The FNDs-MNs can efficiently treat MRSA infected wounds. Biomedical patches are playing an indispensable role in wound infection management. Current efforts have focused on designing smart patches with both treating and sensing abilities to recognize wound infections and kill bacteria efficiently. Here, we present intelligent colorimetric microneedle patches (MNs) integrated with Fe ion-gallic acid coordination polymer nanodots (FNDs) for on-demand treatment and real-time report of infected wounds. Such FNDs are fabricated by coordination reactions among polyvinylpyrrolidone (PVP), gallic acid, and Fe ion, and are loaded inside the MNs using a template replication method (FNDs-MNs). Benefitting from the pH-dependent peroxidase mimic activity of the FNDs, the integrated MNs can catalyze H 2 O 2 to generate much more OH at the acidic condition for bacteria killing. Besides, these FNDs-MNs also possess pH and H 2 O 2 dependent color changes, and thus can timely reflect the wound repair and infection states. During the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infected wounds in mice, the FNDs-MNs exhibit obvious color changes at infected stages and achieve on-demand therapeutic effects. Thus, it is believed that such FNDs-MNs have great potentials for efficient wound infection management and will find wide applications in wound care. [ABSTRACT FROM AUTHOR]

Highlights: [•] Anisotropic colloidal crystal particles (CCPs) were generating by microfluidics. [•] The CCPs in different sizes, structural colors and shapes were generated. [•] Angle-independent rod-like CCPs were used for biological multiplexed assays. [Copyright &y& Elsevier]

• The microfluidic system produced homogeneous porous particles for 3D cell culture. • The microcarriers sustained cell survival and functioning. • The microcarriers responded to stimulations and release insulin. • Transplantation of microcarriers relieved hyperglycemia of diabetic mice. Type 1 diabetes mellitus (T1DM) are characterized by hyperglycemia with pancreatic β cells deficiency, leading to subsequent acute and chronic complications. Effects in recent decades are the trend to develop advanced techniques for β cell culture, of which three-dimensional (3D) cell culture showed promising potentials. Herein, we generate the unique porous microcarriers with pancreatic β cell aggregates loading taking advantages of microfluidic double emulsion techniques. The microcarriers are made of the commixture of poly ethylene glycol diacrylate (PEGDA) and gelatin methacryloyl (GelMA), in which GelMA could promote the biocompatibility of hybrid hydrogel effectively. Since the PEGDA refrain from cell adhesion due to its physical property and the filled biopolymer in the core could function as an extracellular matrix (ECM), cells are able to aggregate in the cores of microcarriers suffused with the biopolymer. Besides, the prompted efficiency of metabolic exchanges on account of the external/interconnected structure of microcarriers is proven to accelerate the accumulation of pancreatic β cell aggregates. It is demonstrated that the fabricated microcarriers with β cells loading provide improvements in the pancreatic function of insulin secretion. These features enable the application of the resultant microcarriers for islet organoid researches, offering an attractive treatment option for diabetes therapies. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bioinspired hemostatic microneedles with pagoda-like structures and DCS coating. • Facile step-by-step mold replication is used to prepare the microneedles. • The hierarchical structure provides physical interlock, enabling tissue adhesion. • The DCS coating ensures swift blood cell coagulation and active hemostasis. • The hemostatic microneedles are effective for acute tissue bleeding of rabbits. Efficient hemostasis is of great significance in clinical and medical fields. Herein, inspired by the hierarchical microstructure of feet or stings of insects, we present a dodecyl-modified chitosan (DCS)-coated pagoda-like multilayer microneedle patch for tissue fixation and rapid hemostasis. Such a microneedle patch is fabricated by a step-by-step mold replication, which is easy-to-operate, flexible, and highly adjustable. The multilayer structure enables the microneedle patch to strongly fix onto diverse tissues via physical interlocking and is not affected by large blood loss or other conditions; while the DCS coating can anchor onto the cell membrane, bring about blood cell coagulation, and thus actively promote hemostasis. It was demonstrated from in-vivo rabbit experiments that acute tissue injuries including liver bleeding, spleen bleeding, and kidney bleeding can be repaired immediately by employing these DCS-coated multilayer microneedle patches. These distinctive features indicate that the presented microneedle patches can find applications in hemostasis and many other biomedical fields. [ABSTRACT FROM AUTHOR]