Recent advances in regenerative biomaterials

Synergistic effects of silica-enriched bioactive glass and tri-calcium phosphate nanocomposites on BMP2 gene expression for bone repair and regeneration applications

This study focuses on the development of biomaterials for bone regeneration highlighting 59S bioactive glass (59S BG), tri-calcium phosphate (TCP), and their 1:1 composite (59S BG/TCP). The synthesized materials demonstrated excellent properties for bone tissue engineering. Characterization revealed their thermal stability up to 900 °C, as confirmed by thermogravimetric analysis (TGA), while X-ray diffraction (XRD) identified calcium phosphate and silicate phases. Functional groups and chemical bonding were elucidated using Fourier transform infrared spectroscopy (FTIR). The composite exhibited remarkable mechanical properties, with a hardness of 167.87 HV and a strength of 680.52 MPa, indicating its suitability for load-bearing applications. Biological evaluations confirmed promising performance, with in-vitro bioactivity showing apatite formation and reduced XRD peak intensity. Biocompatibility assessments revealed hemolysis below 5 % and a 300 % cell proliferation rate by day three ensuring minimal cytotoxicity and favorable blood compatibility. Protein adsorption studies demonstrated strong interactions with bovine serum albumin (BSA) and lysozyme, supporting protein stability. Additionally, the composite showed enhanced osteogenic potential with elevated BMP2 gene expression indicating its capacity to promote robust bone regeneration. The synergy between 59S BG and TCP underscores the composite's potential as a promising material for effective bone repair and regeneration.

Lockd Enhances Mandibular Mesenchymal Stem Cell Proliferation While Inhibiting Osteogenic Capability via Binding With SUZ12 in the Inflammatory Microenvironment

AIM

To investigate the role of lncRNA Lockd in mandibular mesenchymal stem cell (M-MSC) proliferation and osteogenic capability in the inflammatory microenvironment, focusing on its interaction with SUZ12.

MATERIALS AND METHODS

Using lncR Lockd knockdown/overexpression cell models and a murine periodontitis model, we explored Lockd's effects on M-MSC proliferation and osteogenic capability in the inflammatory microenvironment. Predictions from multiple databases and a series of rescue experiments revealed the regulatory role of the Lockd/SUZ12 signalling axis of M-MSC in the inflammatory microenvironment.

RESULTS

Lockd was found to stimulate M-MSC proliferation but impair osteogenic differentiation. The in vitro studies suggested that the activation of Lockd negatively inhibited the osteogenic differentiation process and may ultimately impact bone formation in periodontitis. Mechanistically, it was elucidated that Lockd interacts with SUZ12, a core component of the polycomb repressive complex 2 (PRC2), and may affect the PRC2 complex's role in osteogenic gene expression.

CONCLUSIONS

Lockd boosts the proliferation of M-MSCs but inhibits their osteogenic differentiation by interacting with SUZ12, potentially inhibiting osteogenic capability in the inflammatory microenvironment.

A sterilization method for human decellularized vaginal matrices

Vaginal reconstruction is necessary for various congenital and acquired conditions, including vaginal aplasia, trauma, tumors, and gender incongruency. Current surgical and non-surgical treatments often result in significant complications. Decellularized vaginal matrices (DVMs) from human tissue offer a promising alternative, but require effective sterilization to ensure safety and functionality. This study aimed to develop a sterilization method for decellularized human vaginal wall scaffolds. Based on our previously implemented decellularization technique with minor modifications, we designed and examined three sterilization methods consisting of (i) chemical decellularization, (ii) decellularization with additional peracetic acid/hydrogen peroxide (PAA/H2O2); (iii) decellularization with antibiotic and antimycotic (AAE) based treatment. Sterilization efficacy was evaluated through controlled contamination with common vaginal microbes and sterility testing subsequent to each sterilization method. The extracellular matrix (ECM) structure was assessed via histological staining. Decellularization alone reduced some added bacterial contaminants but did not achieve complete sterilization. PAA/H2O2-sterilization resulted in severe ECM damage, rendering it unsuitable. The AAE-treatment demonstrated effective sterilization without compromising the ECM structure. Combined decellularization and AAE-based treatment forms a viable sterilization method for human vaginal wall tissue, maintaining ECM integrity and achieving effective micro-organism elimination. This method holds potential for clinical application in vaginal transplantation.

3D-printed Ti3C2/polycaprolactone composite scaffold with a DOPA-SDF1 surface modified for bone repair

Large bone defects are a major clinical challenge in bone reconstructive surgery. 3D printing is a powerful technology that enables the manufacture of custom tissue-engineered scaffolds for bone regeneration. Electrical stimulation (ES) is a treatment method for external bone defects that compensates for damaged internal electrical signals and stimulates cell proliferation and differentiation. In this study, we propose a simple, reliable, and versatile strategy to prepare multifunctional 3D printed scaffold combined with ES for bone defect therapy. Firstly, scaffolds composed of polycaprolactone (PCL) and Ti3C2 were prepared by 3D printing technology, and then a stromal cell derived factor 1 (SDF1) containing DOPA tag was loaded onto the scaffold surface. Ti3C2 was selected as the electrode component because of its excellent electrical conductivity. The selection of DOPA-modified SDF-1(DOPA-SDF1) can improve the material binding ability and exert long-term stem cell recruitment function. The results show that prepared 3D printed scaffold (DOPA-SDF1@PCL#Ti3C2) has good hydrophilicity, electrical conductivity, antibacterial property, biocompatibility and stem cell recruitment ability. Furthermore, the expression of osteogenic specific genes in scaffold surface cells was significantly increased when pulse ES (PES) treatment was applied. The results of tibial plateau defect repair experiment showed that DOPA-SDF1@PCL#Ti3C2 scaffold can significantly promote the formation of new bone and collagen fibres. When the DOPA-SDF1@PCL#Ti3C2 scaffold was used in combination with PES therapy, the bone defect regeneration rate was further improved. This kind of scaffold could provide a new strategy for promoting the healing of large bone injuries and could expand the application of adjuvant therapy such as PES.

Effects of cell shape and nucleus shape on epithelial-mesenchymal transition revealed using chimeric micropatterns

Epithelial-mesenchymal transition (EMT) is a key phenotypic switch in cancer metastasis, leading to fatal consequences for patients. Under geometric constraints, the morphology of cancer cells changes in both cellular and subcellular levels, whose effects on EMT are, however, not fully understood. Herein, we designed and fabricated chimeric micropatterns of polystyrene (PS) with adhesion contrast to reveal the impacts of cell shapes and nuclear shapes on EMT in a decoupled way. Cell elongation was modulated via microwell aspect ratios (ARs), and nuclear deformation was generated through a micropillar array in the microwell. Human non-small cell lung cancer cells (A549) were cultured on the quasi-three dimensional micropatterned surfaces, and transforming growth factor-β1 (TGF-β1) was added to induce EMT. We found that chimeric micropatterns upregulated EMT with an increase of cellular AR and nuclear indentation under given TGF-β1. The subsequent assessment of the contractility and oriented assembly of microfilaments elucidated the key role of mechanotransduction in cell elongation and EMT, as proved by myosin inhibition, while it was obstructed by micropillars in the chimeric micropattern. Hence, the micropillar array possessed a nonmonotonic influence, enhancing the EMT of cells with AR of 1, but hindering the EMT with an impact more significant on microwells with large ARs due to the impeded cytoskeleton assembly. This fundamental research has illustrated the complex of cellular and subcellular geometries on cell behaviors including phenotype transition in cancer metastasis.

Exploring the frontiers: The potential and challenges of bioactive scaffolds in osteosarcoma treatment and bone regeneration

The standard treatment for osteosarcoma combines surgery with chemotherapy, yet it is fraught with challenges such as postoperative tumor recurrence and chemotherapy-induced side effects. Additionally, bone defects after surgery often surpass the body's regenerative ability, affecting patient recovery. Bioengineering offers a novel approach through the use of bioactive scaffolds crafted from metals, ceramics, and hydrogels for bone defect repair. However, these scaffolds are typically devoid of antitumor properties, necessitating the integration of therapeutic agents. The development of a multifunctional therapeutic platform incorporating chemotherapeutic drugs, photothermal agents (PTAs), photosensitizers (PIs), sound sensitizers (SSs), magnetic thermotherapeutic agents (MTAs), and naturally occurring antitumor compounds addresses this limitation. This platform is engineered to target osteosarcoma cells while also facilitating bone tissue repair and regeneration. This review synthesizes recent advancements in integrated bioactive scaffolds (IBSs), underscoring their dual role in combating osteosarcoma and enhancing bone regeneration. We also examine the current limitations of IBSs and propose future research trajectories to overcome these hurdles.

Integrin Subtypes and Lamellipodia Mediate Spatial Sensing of RGD Ligands during Cell Adhesion

Understanding how the spatial distribution of adhesive ligands regulates cell behavior is crucial for designing biomaterials. This study investigates how precisely controlled ligand spacing affects cell spreading and integrin subtype engagement. Using engineered polyacrylamide hydrogels with gold nanoparticle arrays, we explored the impact of RGD ligand spacings (30 and 150 nm) on human mesenchymal stromal cells. Cells exhibited distinct morphological behaviors: smaller spacings promoted larger spreading areas, while larger spacings resulted in elongated shapes with reduced spreading. Mechanistically, we found that the α5β1 integrin, not the αvβ3 integrin, played a central role in mediating these responses, alongside lamellipodia formation. Our findings provide critical insights into the spatial sensing of ligands, highlighting the influence of ligand spacing on cellular mechanotransduction and integrin-specific responses. This work advances the understanding of cell-material interactions and offers potential strategies for designing biomaterials to guide cell behavior in tissue engineering.

Recent Advances in Regenerative Endodontics: A Review of Current Techniques and Future Directions

Regenerative endodontics is a rapidly evolving discipline focused on biologically restoring the pulp-dentin complex to revive vitality in non-vital teeth. Unlike traditional endodontic therapies that rely on inert materials to preserve structure, regenerative techniques aim to re-establish natural structure and function by harnessing advancements in tissue engineering. This narrative review examines recent progress in stem cell applications, scaffold development, signaling molecules, and clinical protocols that contribute to successful regenerative outcomes. Advances in stem cell sources, biomimetic scaffolds, and growth factor delivery systems have shown promising results, though challenges such as variability in outcomes and the need for standardized clinical protocols remain. This review also highlights future directions, including gene therapy and three-dimensional bioprinting, which hold the potential to overcome current limitations and pave the way for effective and reliable biologically restorative dental treatments.

Simultaneous co-assembly of collagen and glycosaminoglycans to build a biomimetic extracellular matrix for bone regeneration

Glycosaminoglycans (GAGs), also known as shape modules, are considered junctions that help define the shape of collagen matrix and further promote mineralization during osteogenesis. Many attempts have been made to immobilize GAGs on assembled collagen to modify the latter's surface state. However, it remains unclear how GAGs spontaneously identify collagen molecules during fibrillogenesis in vivo. Understanding the relationship between GAGs and collagen from both the bone physiology and materials science perspectives is of fundamental interest. Here, we introduced hyaluronic acid (HA, a main member of GAGs) during collagen self-assembly, in a process called modification cooperating with self-assembly (MCS). The molecular docking and morphological studies revealed that HA can help define collagen monomer deposition and thus promote fibrillogenesis through steric hindrance or by directly forming hydrogen bonds. Meanwhile, HA acts as a templating chaperone (TC) to increase the local mineral concentration within intrafibrillar channels but does not initiate nucleation, thus improving the crystallinity of formed apatite. The scaffolds synthesized through MCS model significantly improved the physicochemical stability and mechanical strength of collagen-based scaffolds. The optimized scaffolds promoted in-situ osteogenesis by stimulating the osteogenic differentiation of bone mesenchymal stem cells, either in an osteogenic medium, or after implantation into critical calvarial defects. This study provides novel insights towards evolving engineering scaffolds from inert supports to functional substitutes.

Injectable drug-loaded thermosensitive hydrogel delivery system for protecting retina ganglion cells in traumatic optic neuropathy

Currently, generalized therapy for traumatic optic neuropathy (TON) is lacking. Various strategies have been developed to protect and regenerate retinal ganglion cells (RGCs) after TON. Intravitreal injection of supplements has been approved as a promising approach, although serious concerns, such as low delivery efficacy and pain due to frequent injections, remain. In this study, we tested an injectable thermosensitive hydrogel drug delivery system engineered to deliver ciliary neurotrophic factor (CNTF) and triamcinolone acetonide (TA). The results of rheological studies showed that the prepared drug-loaded hydrogel possessed a suitable mechanical modulus of ∼300 Pa, consistent with that of vitreum. The hydrogel exhibited thermosensitive with sustained drug release performance. In vitro co-culture of the CNTF-loaded hydrogel system with primary RGCs also induced significant axon regeneration, with 38.5% increase in neurite length, indicating the regenerative response of the thermosensitive hydrogel drug delivery system. A Sprague-Dawley rat optic nerve crush model was constructed and applied to determine the neuroprotective and regenerative capacities of the system. The results demonstrated that a single intravitreal injection of the drug-loaded hydrogel (PLGA-PEG-PLGA + TA or PLGA-PEG-PLGA + CNTF) significantly increased RGC survival at both 14 and 28 days. The RGC survival rate was 31.05 ± 1.41% for the drug-loaded hydrogel system (the control group was 16.79 ± 1.50%) at Day 28. These findings suggest that the injectable drug-loaded thermosensitive hydrogel delivery system is a promising therapeutic tool for treating optic nerve degeneration.

Nanomaterials based on hollow gold nanospheres for cancer therapy

Gold nanoparticles have recently been exploited as versatile nanocarriers in diagnostic and therapeutic drug delivery for cancer nanomedicine, owing to their biocompatibility, low biotoxicity, surface modifiability and plasma optical properties. A variety of gold nanoparticles have emerged for drug delivery, mainly including gold nanorods, gold nanocages, gold nanostars, gold solid nanospheres and hollow gold nanospheres (HGNs). Among these, HGNs have widely been studied for their higher photothermal conversion efficiency, wider spectral absorption range and stronger surface-enhanced Raman scattering compared with solid gold nanospheres. Therefore, nowadays, researchers prefer to use HGNs to other metal nanocarriers, which can not only play the role of controlled-release drugs but also act as photothermal agents for tumor therapy and diagnosis, due to their properties of surface modification. Combined with the Au-S bond on the surface of HGNs, the targeted preparation is loaded to achieve precise drug delivery. With the assistance of the photothermal characteristics of HGNs themselves, the efficacy of loaded drugs in HGNs is enhanced. In addition, HGNs also have vital values in the field of bioimaging, which serve as photothermal imaging agents and Raman scattering-guided preparations due to their surface-enhanced Raman scattering properties to assist researchers in achieving the purpose of tumor diagnosis. In this review, we summarize the synthesis methods of HGNs and the recent application of HGNs-based nanomaterials in the field of cancer diagnosis and therapy. In addition, the issues to be addressed were pointed out for a bright prospect of HGNs-based nanomaterials.

Deciphering Immunotoxicity in Animal-Derived Biomaterials: A Genomic and Bioinformatics Approach

Immunotoxicity evaluation has been crucial in preclinical testing for implantable animal-derived biomaterials due to their prolonged contact with the human body, which requires stringent safety assessments. By creating experimental models with varying levels of immunotoxicity, this study reveals the decisive role of decellularization treatment in diminishing the immunogenicity of materials, thus ensuring clinical safety. Employing cutting-edge differential gene expression analysis, the research not only accurately quantifies gene expression alterations in immune responses but also, through pathway enrichment analysis, identifies gene networks associated with oncogenesis. This offers novel insights into the mechanisms of immune responses following biomaterial implantation. Additionally, the study highlights the importance of developing highly sensitive immunotoxicity testing methods and validates the efficacy of high-throughput sequencing and bioinformatics tools in assessing biomaterial safety, providing robust scientific support for future preclinical evaluations.

A facile nanopattern modification of silk fibroin electrospun scaffold and the corresponding impact on cell proliferation and osteogenesis

As a well-known natural protein biomaterial, silk fibroin (SF) has shown broad application prospects in typical biomedical fields. However, the mostly used SF from Bombyx mori silkworm lacks specific cell adhesion sites and other bioactive peptide sequences, and there is still significant room for further improvement of their biological functions. Therefore, it is crucial to develop a facile and effective modification strategy for this widely researched biomaterial. In this study, the SF electrospun scaffold has been chosen as a typical SF biomaterial, and air plasma etching has been adopted as a facile nanopattern modification strategy to promote its biological functions. Results demonstrated that the plasma etching could feasibly and effectively create nano-island-like patterns on the complex surface of SF scaffolds, and the detailed nanopattern features could be easily regulated by adjusting the etching time. In addition, the mesenchymal stem cell responses have illustrated that the nanopattern modification could significantly regulate corresponding cell behaviors. Compared with the non-etched scaffold, the 10 min-etched scaffolds (10E scaffold) significantly promoted stem cell proliferation and osteogenic differentiation. Moreover, 10E scaffold has also been confirmed to effectively accelerate vascularization and ectopic osteogenesis in vivo using a rat subcutaneous implantation model. However, the mentioned promoting effects would be weakened or even counteracted with the increase of etching time. In conclusion, this facile modification strategy demonstrated great application potential for promoting cell proliferation and differentiation. Thus, it provided useful guidance to develop excellent SF-based scaffolds suitable for bone and other tissue engineering.

Recent advances in plant-derived polysaccharide scaffolds in tissue engineering: A review

As a natural three-dimensional biopolymer, decellularized plant-derived scaffolds usually comprise various polysaccharides, mostly cellulose, pectin, and hemicellulose. They are characterized by natural biocompatibility and porous structures. The emergence of decellularized purified polysaccharide scaffolds provides an attractive method to overcome the challenges associated with nutrient delivery and biocompatibility, as they serve as optimal non-immune environments for stem cell adhesion and proliferation. To date, limited corresponding literature is available to systemically summarize the development and potential of these scaffolds in tissue engineering. Therefore, the current review summarized the biomimetic properties of plant-derived polysaccharide scaffolds and the latest progress in tissue engineering applications. This review first discusses the advantages of decellularized plant-derived polysaccharide scaffolds by briefly introducing their features and current limitations in clinical applications. Subsequently, the latest progress in emerging applications of regenerative biomaterials is reviewed, followed by a discussion of the studies on the interactions of biomaterials with cells and tissues. Finally, challenges in obtaining reliable scaffolds and possible future directions are discussed.

Soft material drilling: A thermo-mechanical analysis of polyurethane foam for biomimetic bone scaffolds and optimization of process parameters using Taguchi method

Drilling is a widely employed technique in machining processes, crucial for efficient material removal. However, when applied to living tissues, its invasiveness must be carefully considered. This study investigates drilling processes on polyurethane foam blocks mimicking human bone mechanical properties. Various drill bit types (118° twist, 135° twist, spherical, and conical), drilling speeds (1000-1600 rpm), and feed rates (20-80 mm/min) were examined to assess temperature elevation during drilling. The Taguchi method facilitated systematic experiment design and optimization. Signal-to-noise (S/N) ratio and analysis of variance (ANOVA) identified significant drilling parameters affecting temperature rise. Validation was conducted through confirmation testing. Results indicate that standard twist drill bits with smaller point angles, lower drilling speeds, and higher feed rates effectively minimize temperature elevation during drilling.

Maglev-fabricated long and biodegradable stent for interventional treatment of peripheral vessels

While chronic limb-threatening ischemia is a serious peripheral artery disease, the lack of an appropriate stent significantly limits the potential of interventional treatment. In spite of much progress in coronary stents, little is towards peripheral stents, which are expected to be both long and biodegradable and thus require a breakthrough in core techniques. Herein, we develop a long and biodegradable stent with a length of up to 118 mm based on a metal-polymer composite material. To achieve a well-prepared homogeneous coating on a long stent during ultrasonic spraying, a magnetic levitation is employed. In vivo degradation of the stent is investigated in rabbit abdominal aorta/iliac arteries, and its preclinical safety is evaluated in canine infrapopliteal arteries. First-in-man implantation of the stent is carried out in the below-the-knee artery. The 13 months' follow-ups demonstrate the feasibility of the long and biodegradable stent in clinical applications.

Autophagy inhibition mediated via an injectable and NO-releasing hydrogel for amplifying the antitumor efficacy of mild magnetic hyperthermia

While mild hyperthermia holds great potential in the treatment of solid tumors, the thermal stress-triggered self-repairing autophagy significantly compromises its efficacy. To circumvent this obstacle, an injectable hydrogel (NO-Gel) composed of thermosensitive poly(ethylene glycol)-polypeptide copolymers modified with abundant NO donors on their side chains is developed. Meanwhile, ferrimagnetic Zn0.5Fe2.5O4 magnetic nanoparticles (MNPs) with high magnetic-heat conversion efficiency are synthesized and loaded into NO-Gel to obtain MNPs@NO-Gel. The MNPs@NO-Gel system exhibits a sol-gel transition upon heating, and has the ability to perform multiple magnetic hyperthermia therapy (MHT) after only one administration due to the even distribution and strong immobilization of MNPs in NO-Gel. NO can be continuously liberated from NO-Gel and this process is markedly accelerated by MHT. Additionally, MNPs@NO-Gel maintains its integrity in vivo for over one month and the released MNPs are metabolized by the spleen. After a single administration of MNPs@NO-Gel at the tumor site, three mild MHT treatments with similar effects are fulfilled, and the sufficient supply of NO effectively inhibits MHT-induced autophagic flux via blocking the formation of autophagosomes and synchronously destroying lysosomes, thereby substantially boosting the efficacy of mild MHT. As a consequence, CT-26 colon tumors are completely eliminated without causing severe side-effects.

Enhancing the immunomodulatory osteogenic properties of Ti-Mg alloy by Mg2+-containing nanostructures

Facilitating an appropriate immune response is crucial for promoting bone tissue regeneration upon biomaterial implantation. In this study, the Mg2+-containing nanostructures on the surface of Ti-1.25Mg alloy were prepared by a one-step hydrothermal reaction method via regulating pH value to enhance the immunomodulatory osteogenic properties of Ti-Mg alloys. In neutral (HT7) or alkaline (HT9) hydrothermal treatment (HT) solution, the size of MgTiO3 nanostructures formed on the surface of Ti-1.25Mg alloy is smaller than that in acidic HT solution (HT5), and lamellar Mg(OH)2 nanostructures are found in HT7 and HT9. In addition, the sample surface has a lower roughness and higher wettability with increasing pH value. The Mg2+-containing nanostructures on the Ti-1.25Mg alloy inhibited inflammatory response by promoting the polarization of M2 macrophages, thereby promoting osteogenesis in vitro. The micro-CT and histological assessment proved that the regeneration of bone defect was faster in HT7 than the Ti-1.25Mg in vivo. Mechanically, Mg2+-containing nanostructures can mediate the immune response of macrophages via upregulating integrins α5β1 and inhibiting Toll-like receptors (TLR-4), subsequently inhibiting the NF-κB signaling pathway. Overall, osteoimmunity-regulating Mg2+-containing nanostructures on Ti-1.25Mg present a promising biomaterial for bone repair.

Constructing a highly efficient multifunctional carbon quantum dot platform for the treatment of infectious wounds

Antibiotic resistance poses a huge threat to public health, which has increased the difficulty and transmission of disease treatment, as well as the burden and cost of medical institutions. In response to the current problems and challenges in inflammation control and treatment of bacterial infected wounds, inspired by antibacterial mechanisms based on active elements such as N, S, Cu and tannic acid (TA), a highly efficient multifunctional carbon quantum dot platform was proposed in this study and constructed through their special assembly in a solvothermal reaction system for the treatment of infected wounds. By introducing active elements such as N, S and Cu, this carbon quantum dot platform is endowed with antibacterial properties, while also achieving good angiogenesis promoting performance through the use of ion Cu. Meanwhile, the good antioxidant activity of TA (one of the precursors used) enables this platform to have better immunomodulatory performance in vivo. The research results on the treatment of bacterial infection models indicate that the multifunctional carbon quantum dots obtained can accelerate the healing of infected wounds by inhibiting bacterial infection, regulating immunoreaction, accelerating collagen deposition and promoting angiogenesis. This multifunctional carbon quantum dot platform shows good clinical application prospects in treating bacterial infected wounds. Additionally, the fluorescence characteristics of such carbon dots can be expected to realize visual therapy in the future.

Enhancing tumor photodynamic synergistic therapy efficacy through generation of carbon radicals by Prussian blue nanomedicine

Significant progress has been achieved in tumor therapies utilizing nano-enzymes which could convert hydrogen peroxide into reactive oxygen species (ROS). However, the ROS generated by these enzymes possess a short half-life and exhibit limited diffusion within cells, making it challenging to inflict substantial damage on major organelles for effective tumor therapy. Therefore, it becomes crucial to develop a novel nanoplatform that could extend radicals half-life. Artesunate (ATS) is a Fe (II)-dependent drug, while the limited availability of iron (II), coupled with the poor aqueous solubility of ATS, limits its application. Here, Prussian blue (PB) was selected as a nano-carrier to release Fe (II), thus constructing a hollow Prussian blue/artesunate/methylene blue (HPB/ATS/MB) nanoplatform. HPB degraded and released iron(III), ATS and MB, under the combined effects of NIR irradiation and the unique tumor microenvironment. Moreover, Fe (III) exploited GSH to formation of Fe (II), disturbing the redox homeostasis of tumor cells and Fe (II) reacted with H2O2 and ATS to generate carbon radicals with a long half-life in situ. Furthermore, MB generates 1O2 under laser irradiation conditions. In vitro and in vivo experiments have demonstrated that the HPB/ATS/MB NPs exhibit a synergistic therapeutic effect through photothermal therapy, photodynamic therapy and radical therapy.

Toward Fully Automated Personalized Orthopedic Treatments: Innovations and Interdisciplinary Gaps

Personalized orthopedic devices are increasingly favored for their potential to enhance long-term treatment success. Despite significant advancements across various disciplines, the seamless integration and full automation of personalized orthopedic treatments remain elusive. This paper identifies key interdisciplinary gaps in integrating and automating advanced technologies for personalized orthopedic treatment. It begins by outlining the standard clinical practices in orthopedic treatments and the extent of personalization achievable. The paper then explores recent innovations in artificial intelligence, biomaterials, genomic and proteomic analyses, lab-on-a-chip, medical imaging, image-based biomechanical finite element modeling, biomimicry, 3D printing and bioprinting, and implantable sensors, emphasizing their contributions to personalized treatments. Tentative strategies or solutions are proposed to address the interdisciplinary gaps by utilizing innovative technologies. The key findings highlight the need for the non-invasive quantitative assessment of bone quality, patient-specific biocompatibility, and device designs that address individual biological and mechanical conditions. This comprehensive review underscores the transformative potential of these technologies and the importance of multidisciplinary collaboration to integrate and automate them into a cohesive, intelligent system for personalized orthopedic treatments.

Sustainable Release Selenium Laden with SiO2 Restoring Peripheral Nerve Injury via Modulating PI3K/AKT Pathway Signaling Pathway

Background

Inhibiting ROS overproduction is considered a very effective strategy for the treatment of peripheral nerve injuries, and Se has a remarkable antioxidant effect; however, since the difference between the effective concentration of Se and the toxic dose is not large, we synthesized a nanomaterial that can release Se slowly so that it can be used more effectively.

Methods

Se@SiO2 NPs were synthesized using a mixture of Cu2-x Se nanocrystals, and the mechanism of action of Se@SiO2 NPs was initially explored by performing sequencing, immunofluorescence staining and Western blotting of cellular experiments. The mechanism of action of Se@SiO2 NPs was further determined by performing behavioral assays after animal experiments and by sampling the material for histological staining, immunofluorescence staining, and ELISA. The effects, mechanisms and biocompatibility of Se@SiO2 NPs for peripheral nerve regeneration were determined.

Results

Porous Se@SiO2 was successfully synthesized, had good particle properties, and could release Se slowly. CCK-8 experiments revealed that the optimal experimental doses were 100 μM H2O2 and 200 μg/mL Se@SiO2, and RNA-seq revealed that porous Se@SiO2 was associated with cell proliferation, apoptosis, and the PI3K/AKT pathway. WB showed that porous Se@SiO2 could increase the expression of cell proliferation antigens (PCNA and S100) and antiapoptotic proteins (Bcl-2), decrease the expression of proapoptotic proteins (Bax), and increase the expression of antioxidative stress proteins (Nrf2, HO-1, and SOD2). EdU cell proliferation and ROS fluorescence assays showed that porous Se@SiO2 promoted cell proliferation and reduced ROS levels. The therapeutic effect of LY294002 (a PI3K/AKT pathway inhibitor) was decreased significantly and its effect was lost when it was added simultaneously with porous Se@SiO2. Animal experiments revealed that the regenerated nerve fiber density, myelin thickness, axon area, gastrocnemius muscle wet-to-weight ratio, myofiber area, sciatic nerve function index (SFI), CMAP, apoptotic cell ratio, and levels of antioxidative stress proteins and anti-inflammatory factors were increased following the administration of porous Se@SiO2. The levels of oxidative stress proteins and anti-inflammatory factors were significantly greater in the Se@SiO2 group than in the PNI group, and the effect of LY294002 was decreased significantly and was lost when it was added simultaneously with porous Se@SiO2.

Conclusion

Se@SiO2 NPs are promising, economical and effective Se-releasing nanomaterials that can effectively reduce ROS production, inhibit apoptosis and promote cell proliferation after nerve injury via the PI3K/AKT pathway, ultimately accelerating nerve regeneration. These findings could be used to design new, promising drugs for the treatment of peripheral nerve injury.

Regulatory science promotes the translation of transcatheter tricuspid valve repair/replacement devices

For patients with symptomatic and severe tricuspid regurgitation but inoperable with open surgery, transcatheter tricuspid valve intervention (TTVI) is a procedure of great clinical value. TTVI products include repair and replacement devices. TTVI products are one of the hotspots of investigation now, with different innovative biomaterials and structural designs in trials to satisfy divergent indications and reduce complications. With the emerging biomaterials, the technical difficulty of structural design will be greatly reduced, spurring further product innovation and development. The innovativeness and complexity of TTVI products have brought challenges to academia, industry, and regulatory agencies. Regulatory science provides a bridge to address these difficulties and challenges. This perspective article introduces the latest development of the TTVI products. With traditional methods, regulatory agencies face challenges in evaluating the safety and efficacy of TTVr/TTVR devices given the uncertainty of clinical use and the diversity of innovative structural design. This perspective article analyzes the regulatory challenges and discusses regulatory science that can be developed to assess the safety, efficacy, quality and performance of such products: including new approaches for innovative devices, pre-review path, computer modeling and simulation, accelerated wear testing methods for transcatheter heart valves and evidence-based research. This article reveals for the first time how to apply regulatory science systematically to TTVI products, which is of great relevance to their development and translation.

Dissolvable microneedles loaded ginsenoside Rg3 liposome: a transdermal delivery approach for alopecia treatment

The skin stratum corneum (SC) barrier function will interfere with the absorption of topical treatment and reduce the drug's therapeutic effect on alopecia. Microneedles (MNs) can penetrate the skin barrier and deliver drugs to the dermis. Furthermore, MNs can mechanically stimulate the skin, which promotes hair growth. Thus, we designed a green and dissolvable composite microneedle made of hyaluronic acid (HA) and Bletilla striata polysaccharide (BSP) to encapsulate cholesterol-free ginsenoside Rg3 liposomes (Rg3-LPs) to avoid cholesterol metabolism-producing testosterone to inhibit hair regeneration and minimize the effect of the SC barrier on liposomes absorption. HA and BSP can enhance the mechanical strength of Rg3-MNs to ensure the transport of liposomes to the hair follicle (HF) region while causing minimal skin irritation and guaranteeing cell compatibility. In addition, HA increased hair density and was more conducive to hair regeneration. In telogen effluvium (TE) and testosterone-induced androgenetic alopecia (AGA) animals, Rg3-MNs achieved comparable efficacy to minoxidil with low-frequency treatment and the quality of regenerated hair was higher. Furthermore, quantitative characterization and transcriptome sequencing results showed that Rg3-MNs promoted hair regeneration by promoting the expression of Wnt3a and Wnt10b genes, activating the Wnt/β-catenin pathway. Therefore, Rg3-MNs present broad prospects in the treatment of alopecia.

Electrophoretic Deposition of Chitosan Coatings on the Porous Titanium Substrate

Medicine is looking for solutions to help implant patients recover more smoothly. The porous implants promote osteointegration, thereby providing better stabilization. Introducing porosity into metallic implants enhances their biocompatibility and facilitates osteointegration. The introduction of porosity is also associated with a reduction in Young's modulus, which reduces the risk of tissue outgrowth around the implant. However, the risk of chronic inflammation remains a concern, necessitating the development of coatings to mitigate adverse reactions. An interesting biomaterial for such modifications is chitosan, which has antimicrobial, antifungal, and osteointegration properties. In the present work, a porous titanium biomaterial was obtained by powder metallurgy, and electrophoretic deposition of chitosan coatings was used to modify its surface. This study investigated the influence of ethanol content in the deposition solution on the quality of chitosan coatings. The EPD process facilitates the control of coating thickness and morphology, with higher voltages resulting in thicker coatings and increased pore formation. Ethanol concentration in the solution affects coating quality, with higher concentrations leading to cracking and peeling. Optimal coating conditions (30 min/10 V) yield high-quality coatings, demonstrating excellent cell viability and negligible cytotoxicity. The GIXD and ATR-FTIR analysis confirmed the presence of deposited chitosan coatings on Ti substrates. The microstructure of the chitosan coatings was examined by scanning electron microscopy. Biological tests showed no cytotoxicity of the obtained materials, which allows for further research and the possibility of their use in medicine. In conclusion, EPD offers a viable method for producing chitosan-based coatings with controlled properties for biomedical applications, ensuring enhanced patient outcomes and implant performance.

Fluorinated Organic Polymers for Cancer Drug Delivery

In the realm of cancer therapy, the spotlight is on nanoscale pharmaceutical delivery systems, especially polymer-based nanoparticles, for their enhanced drug dissolution, extended presence in the bloodstream, and precision targeting achieved via surface engineering. Leveraging the amplified permeation and retention phenomenon, these systems concentrate therapeutic agents within tumor tissues. Nonetheless, the hurdles of systemic toxicity, biological barriers, and compatibility with living systems persist. Fluorinated polymers, distinguished by their chemical idiosyncrasies, are poised for extensive biomedical applications, notably in stabilizing drug metabolism, augmenting lipophilicity, and optimizing bioavailability. Material science heralds the advent of fluorinated polymers that, by integrating fluorine atoms, unveil a suite of drug delivery merits: the hydrophobic traits of fluorinated alkyl chains ward off lipid or protein disruption, the carbon-fluorine bond's stability extends the drug's lifecycle in the system, and a lower alkalinity coupled with a diminished ionic charge bolsters the drug's ability to traverse cellular membranes. This comprehensive review delves into the utilization of fluorinated polymers for oncological pharmacotherapy, elucidating their molecular architecture, synthetic pathways, and functional attributes, alongside an exploration of their empirical strengths and the quandaries they encounter in both experimental and clinical settings.

Global Stem Cell Research in Orthopaedics: A Bibliometric Study from 1995 to 2020

Background

The research field of stem cell-based therapies in orthopaedics has witnessed significant growth in the recent past. We aimed to identify and analyze the bibliometric characteristics of the global highly cited papers (HCPs) in stem cell research in orthopaedics.

Methods

This study relied on secondary data extracted from Scopus, Elsevier's abstract and citation database. An advanced search string was employed, for the period from 1995 to 2020. For each paper, the extracted information included the number of citations, title, authors (name, number, authorship position, and country), year of publication, title of the journals, study design, and thematic field. The VOSviewer (1.6.20) was used to uncover relationships between authors, institutions, keywords, and publications.

Results

There were a total of 1427 publications and out of these 186 papers had 100 or more citations (range 100-2644) and were considered as HCPs. The average citation per paper (CPP) was 265.8. Only 4% of the top HCPs contributed 20% of the total citations of all HCPs. All the HCPs were published from high-income countries, and the USA was the leading country in all aspects of publication on stem cell research. Méndez-Ferrer S registered the highest citation (n = 2644), Prockop DJ was the most prolific author (n = 8 papers), and Harvard Medical School, USA emerged as the most prolific organization with 12 HCPs.

Conclusion

Global research in stem cell therapies for orthopaedic problems is making strides, and is an emerging field of research. Stem cell research offers the potential for improved treatment outcomes for various musculoskeletal conditions.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s43465-024-01160-0.

The therapeutic efficacy of different configuration nano-polydopamine drug carrier systems with photothermal synergy against head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignant tumor worldwide. Considering its special anatomical site and the progressive resistance to chemotherapy drugs, the development of more effective, minimally invasive and precise treatment methods is urgently needed. Nanomaterials, given their special properties, can be used as drug carrier systems to improve the therapeutic effect and reduce the adverse effects. The drug carrier systems with photothermal effect can promote the killing of cancer cells and help overcome drug resistance through heat stress. We selected dopamine, a simple raw material, and designed and synthesized three different configurations of nano-polydopamine (nPDA) nanomaterials, including nPDA balls, nPDA plates and porous nPDA balls. In addition to the self-polymerization and self-assembly, nPDA has high photothermal conversion efficiency and can be easily modified. Moreover, we loaded cisplatin into three different configurations of nPDA, creating nPDA-cis (the nano-drug carrier system with cisplatin), and comparatively studied the properties and antitumor effects of all the nPDA and nPDA-cis materials in vitro and nPDA-cis in vivo. We found that the photothermal effect of the nPDA-cis balls drug carrier system had synergistic effect with cisplatin, resulting in excellent antitumor effect and good clinical application prospects. The comparison of the three different configurations of drug carrier systems suggested the importance of optimizing the spatial configuration design and examining the physical and chemical properties in the future development of nano-drug carrier systems. In this study, we also noted the duality and complexity of the influences of heat stress on tumors in vitro and in vivo. The specific mechanisms and the synergy with chemotherapy and immunotherapy will be an important research direction in the future.

Epithelial-Mesenchymal Transition of Cancer Cells on Micropillar Arrays

Epithelial-mesenchymal transition (EMT) is critical for tumor invasion and many other cell-relevant processes. While much progress has been made about EMT, no report concerns the EMT of cells on topological biomaterial interfaces with significant nuclear deformation. Herein, we prepared a poly(lactide-co-glycolide) micropillar array with an appropriate dimension to enable significant deformation of cell nuclei and examined EMT of a human lung cancer epithelial cell (A549). We show that A549 cells undergo serious nuclear deformation on the micropillar array. The cells express more E-cadherin and less vimentin on the micropillar array than on the smooth surface. After transforming growth factor-β1 (TGF-β1) treatment, the expression of E-cadherin as an indicator of the epithelial phenotype is decreased and the expression of vimentin as an indicator of the mesenchymal phenotype is increased for the cells both on smooth surfaces and on micropillar arrays, indicating that EMT occurs even when the cell nuclei are deformed and the culture on the micropillar array more enhances the expression of vimentin. Expression of myosin phosphatase targeting subunit 1 is reduced in the cells on the micropillar array, possibly affecting the turnover of myosin light chain phosphorylation and actin assembly; this makes cells on the micropillar array prefer the epithelial-like phenotype and more sensitive to TGF-β1. Overall, the micropillar array exhibits a promoting effect on the EMT.

β-Cyclodextrin-based nanoassemblies for the treatment of atherosclerosis

Atherosclerosis, a chronic and progressive condition characterized by the accumulation of inflammatory cells and lipids within artery walls, remains a leading cause of cardiovascular diseases globally. Despite considerable advancements in drug therapeutic strategies aimed at managing atherosclerosis, more effective treatment options for atherosclerosis are still warranted. In this pursuit, the emergence of β-cyclodextrin (β-CD) as a promising therapeutic agent offers a novel therapeutic approach to drug delivery targeting atherosclerosis. The hydrophobic cavity of β-CD facilitates its role as a carrier, enabling the encapsulation and delivery of various therapeutic compounds to affected sites within the vasculature. Notably, β-CD-based nanoassemblies possess the ability to reduce cholesterol levels, mitigate inflammation, solubilize hydrophobic drugs and deliver drugs to affected tissues, making these nanocomponents promising candidates for atherosclerosis management. This review focuses on three major classes of β-CD-based nanoassemblies, including β-CD derivatives-based, β-CD/polymer conjugates-based and polymer β-CD-based nanoassemblies, highlighting a variety of formulations and assembly methods to improve drug delivery and therapeutic efficacy. These β-CD-based nanoassemblies exhibit a variety of therapeutic mechanisms for atherosclerosis and offer systematic strategies for overcoming barriers to drug delivery. Finally, we discuss the present obstacles and potential opportunities in the development and application of β-CD-based nanoassemblies as novel therapeutics for managing atherosclerosis and addressing cardiovascular diseases.

Hybrid films loaded with 5-fluorouracil and Reglan for synergistic treatment of colon cancer via asynchronous dual-drug delivery

Combination therapy with oral administration of several active ingredients is a popular clinical treatment for cancer. However, the traditional method has poor convenience, less safety, and low efficiency for patients. The combination of traditional pharmaceutical techniques and advanced material conversion methods can provide new solutions to this issue. In this research, a new kind of hybrid film was created via coaxial electrospraying, followed by a casting process. The films were composed of Reglan and 5-fluorouracil (5-FU)-loaded cellulose acetate (CA) core-shell particles in a polyvinylpyrrolidone (PVP) film matrix. Microscopic observations of these films demonstrated a solid cross section loaded with core-shell particles. X-ray diffraction and Fourier-transform infrared tests verified that the Reglan and 5-FU loaded in the films showed amorphous states and fine compatibilities with the polymeric matrices, i.e., PVP and CA, respectively. In vitro dissolution tests indicated that the films were able to provide the desired asynchronous dual-drug delivery, fast release of Reglan, and sustained release of 5-FU. The controlled release mechanisms were shown to be an erosion mechanism for Reglan and a typical Fickian diffusion mechanism for 5-FU. The protocols reported herein pioneer a new approach for fabricating biomaterials loaded with multiple drugs, each with its own controlled release behavior, for synergistic cancer treatment.

Development of 3D Printed Biodegradable, Entirely X-ray Visible Stents for Rabbit Carotid Artery Implantation

Biodegradable stents are considered a promising strategy for the endovascular treatment of cerebrovascular diseases. The visualization of biodegradable stents is of significance during the implantation and long-term follow-up. Endowing biodegradable stents with X-ray radiopacity can overcome the weakness of intrinsic radioparency of polymers. Hence, this work focuses on the development of an entirely X-ray visible biodegradable stent (PCL-KIO3) composed of polycaprolactone (PCL) and potassium iodate via physical blending and 3D printing. The in vitro results show that the introduction of potassium iodate makes the 3D-printed PCL stents visualizable under X-ray. So far, there is inadequate study about polymeric stent visualization in vivo. Therefore, PCL-KIO3 stents are implanted into the rabbit carotid artery to evaluate the biosafety and visibility performance. During stent deployment, the visualization of the PCL-KIO3 stent effectively helps to understand the position and dilation status of stents. At 6-month follow-up, the PCL-KIO3 stent could still be observed under X-ray and maintains excellent vessel patency. To sum up, this study demonstrates that PCL-KIO3 stent may provide a robust strategy for biodegradable stent visualization.

Electrospun Scaffolds are Not Necessarily Always Made of Nanofibers as Demonstrated by Polymeric Heart Valves for Tissue Engineering

In the last 30 years, there are ≈60 000 publications about electrospun nanofibers, but it is still unclear whether nanoscale fibers are really necessary for electrospun tissue engineering scaffolds. The present report puts forward this argument and reveals that compared with electrospun nanofibers, microfibers with diameter of ≈3 µm (named as "oligo-micro fiber") are more appropriate for tissue engineering scaffolds owing to their better cell infiltration ability caused by larger pores with available nuclear deformation. To further increase pore sizes, electrospun poly(ε-caprolactone) (PCL) scaffolds are fabricated using latticed collectors with meshes. Fiber orientation leads to sufficient mechanical strength albeit increases porosity. The latticed scaffolds exhibit good biocompatibility and improve cell infiltration. Under aortic conditions in vitro, the performances of latticed scaffolds are satisfactory in terms of the acute systolic hemodynamic functionality, except for the higher regurgitation fraction caused by the enlarged pores. This hierarchical electrospun scaffold with sparse fibers in macropores and oligo-micro fibers in filaments provides new insights into the design of tissue engineering scaffolds, and tissue engineering may provide living heart valves with regenerative capabilities for patients with severe valve disease in the future.

Preparation and evaluation of decellularized epineurium as an anti-adhesive biofilm in peripheral nerve repair

Following peripheral nerve anastomosis, the anastomotic site is prone to adhesions with surrounding tissues, consequently impacting the effectiveness of nerve repair. This study explores the development and efficacy of a decellularized epineurium as an anti-adhesive biofilm in peripheral nerve repair. Firstly, the entire epineurium was extracted from fresh porcine sciatic nerves, followed by a decellularization process. The decellularization efficiency was then thoroughly assessed. Subsequently, the decellularized epineurium underwent proteomic analysis to determine the remaining bioactive components. To ensure biosafety, the decellularized epineurium underwent cytotoxicity assays, hemolysis tests, cell affinity assays, and assessments of the immune response following subcutaneous implantation. Finally, the functionality of the biofilm was determined using a sciatic nerve transection and anastomosis model in rats. The result indicated that the decellularization process effectively removed cellular components from the epineurium while preserving a number of bioactive molecules, and this decellularized epineurium was effective in preventing adhesion while promoting nerve repairment and functional recovery. In conclusion, the decellularized epineurium represents a novel and promising anti-adhesion biofilm for enhancing surgical outcomes of peripheral nerve repair.

Application of magnetism in tissue regeneration: recent progress and future prospects

Tissue regeneration is a hot topic in the field of biomedical research in this century. Material composition, surface topology, light, ultrasonic, electric field and magnetic fields (MFs) all have important effects on the regeneration process. Among them, MFs can provide nearly non-invasive signal transmission within biological tissues, and magnetic materials can convert MFs into a series of signals related to biological processes, such as mechanical force, magnetic heat, drug release, etc. By adjusting the MFs and magnetic materials, desired cellular or molecular-level responses can be achieved to promote better tissue regeneration. This review summarizes the definition, classification and latest progress of MFs and magnetic materials in tissue engineering. It also explores the differences and potential applications of MFs in different tissue cells, aiming to connect the applications of magnetism in various subfields of tissue engineering and provide new insights for the use of magnetism in tissue regeneration.

Regulation of mitochondrial network architecture and function in mesenchymal stem cells by micropatterned surfaces

Mitochondrial network architecture, which is closely related to mitochondrial function, is mechanically sensitive and regulated by multiple stimuli. However, the effects of microtopographic cues on mitochondria remain poorly defined. Herein, polycaprolactone (PCL) surfaces were used as models to investigate how micropatterns regulate mitochondrial network architecture and function in rat adipose-derived stem cells (rASCs). It was found that large pit (LP)-induced rASCs to form larger and more complex mitochondrial networks. Consistently, the expression of key genes related to mitochondrial dynamics revealed that mitochondrial fusion (MFN1 and MFN2) and midzone fission (DRP1 and MFF) were increased in rASCs on LP. In contrast, the middle pit (MP)-enhanced mitochondrial biogenesis, as evidenced by the larger mitochondrial area and higher expression of PGC-1. Both LP and MP promoted ATP production in rASCs. It is likely that LP increased ATP levels through modulating mitochondrial network architecture while MP stimulated mitochondria biogenesis to do so. Our study clarified the regulation of micropatterned surfaces on mitochondria, highlighting the potential of LP and MP as a simple platform to stimulate mitochondria and the subsequent cellular function of MSCs.

Development and Evaluation of Alginate- and Carrageenan-Incorporated Scaffold for Bone Regeneration: An In Vitro Study

INTRODUCTION

Periodontitis, a persistent inflammatory condition, results in the deterioration of both the hard and soft tissues in the periodontium, leading to the formation of intrabony defects. Restoring the lost tissues, particularly bone, is possible through tissue engineering techniques utilizing scaffolds made from different polymers. Consequently, this research focuses on creating and assessing a scaffold infused with alginate (Sigma Aldrich, Gillingham, UK) and carrageenan (Sigma Aldrich, Gillingham, UK) for the purpose of bone regeneration.

METHODS

An in vitro investigation was conducted to assess the characteristics of the recently formulated scaffold. Spectroscopic analysis, tensile strength testing, scanning electron microscopy (SEM) analysis, and degradation testing were carried out to evaluate both the physical and biological attributes of the scaffold.

RESULTS

IBM SPSS Statistics for Windows, V. 1.2 (IBM Corp., Armonk, NY, USA) was used for statistical analysis. A one-way ANOVA test was done to determine the significance of tensile strength, and a paired t-test was done to check the significance of the degradation test. The in vitro research unveiled notable distinctions in the physical and biological attributes between the scaffold infused with alginate and carrageenan and the PerioCol® (p<0.05).

CONCLUSION

The scaffold incorporating alginate and carrageenan demonstrated superior outcomes concerning parameters such as tensile stress and strain, degradation rate, percentage bone volume, and object surface density when contrasted with the conventional PerioCol®. Therefore, the scaffold infused with alginate and carrageenan emerges as a promising candidate for bone regeneration.

Engineered shapes using electrohydrodynamic atomization for an improved drug delivery

The shapes of micro- and nano-products have profound influences on their functional performances, which has not received sufficient attention during the past several decades. Electrohydrodynamic atomization (EHDA) techniques, mainly include electrospinning and electrospraying, are facile in manipulate their products' shapes. In this review, the shapes generated using EHDA for modifying drug release profiles are reviewed. These shapes include linear nanofibers, round micro-/nano-particles, and beads-on-a-string hybrids. They can be further divided into different kinds of sub-shapes, and can be explored for providing the desired pulsatile release, sustained release, biphasic release, delayed release, and pH-sensitive release. Additionally, the shapes resulted from the organizations of electrospun nanofibers are discussed for drug delivery, and the shapes and inner structures can be considered together for developing novel drug delivery systems. In future, the shapes and the related shape-performance relationships at nanoscale, besides the size, inner structure and the related structure-performance relationships, would further play their important roles in promoting the further developments of drug delivery field. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Unraveling Endothelial Cell Migration: Insights into Fundamental Forces, Inflammation, Biomaterial Applications, and Tissue Regeneration Strategies

Cell migration is vital for many fundamental biological processes and human pathologies throughout our life. Dynamic molecular changes in the tissue microenvironment determine modifications of cell movement, which can be reflected either individually or collectively. Endothelial cell (EC) migratory adaptation occurs during several events and phenomena, such as endothelial injury, vasculogenesis, and angiogenesis, under both normal and highly inflammatory conditions. Several advantageous processes can be supported by biomaterials. Endothelial cells are used in combination with various types of biomaterials to design scaffolds promoting the formation of mature blood vessels within tissue engineered structures. Appropriate selection, in terms of scaffolding properties, can promote desirable cell behavior to varying degrees. An increasing amount of research could lead to the creation of the perfect biomaterial for regenerative medicine applications. In this review, we summarize the state of knowledge regarding the possible systems by which inflammation may influence endothelial cell migration. We also describe the fundamental forces governing cell motility with a specific focus on ECs. Additionally, we discuss the biomaterials used for EC culture, which serve to enhance the proliferative, proangiogenic, and promigratory potential of cells. Moreover, we introduce the mechanisms of cell movement and highlight the significance of understanding these mechanisms in the context of designing scaffolds that promote tissue regeneration.

Biomaterials for Protein Delivery: Opportunities and Challenges to Clinical Translation

The development of biomaterials for protein delivery is an emerging field that spans materials science, bioengineering, and medicine. In this review, we highlight the immense potential of protein-delivering biomaterials as therapeutic options and discuss the multifaceted challenges inherent to the field. We address current advancements and approaches in protein delivery that leverage stimuli-responsive materials, harness advanced fabrication techniques like 3D printing, and integrate nanotechnologies for greater targeting and improved stability, efficacy, and tolerability profiles. We also discuss the demand for highly complex delivery systems to maintain structural integrity and functionality of the protein payload. Finally, we discuss barriers to clinical translation, such as biocompatibility, immunogenicity, achieving reliable controlled release, efficient and targeted delivery, stability issues, scalability of production, and navigating the regulatory landscape for such materials. Overall, this review summarizes insights from a survey of the current literature and sheds light on the interplay between innovation and the practical implementation of biomaterials for protein delivery.

Wet 3D printing of biodegradable porous scaffolds to enable room-temperature deposition modeling of polymeric solutions for regeneration of articular cartilage

Tissue engineering has emerged as an advanced strategy to regenerate various tissues using different raw materials, and thus it is desired to develop more approaches to fabricate tissue engineering scaffolds to fit specific yet very useful raw materials such as biodegradable aliphatic polyester like poly (lactide-co-glycolide) (PLGA). Herein, a technique of 'wet 3D printing' was developed based on a pneumatic extrusion three-dimensional (3D) printer after we introduced a solidification bath into a 3D printing system to fabricate porous scaffolds. The room-temperature deposition modeling of polymeric solutions enabled by our wet 3D printing method is particularly meaningful for aliphatic polyester, which otherwise degrades at high temperature in classic fuse deposition modeling. As demonstration, we fabricated a bilayered porous scaffold consisted of PLGA and its mixture with hydroxyapatite for regeneration of articular cartilage and subchondral bone. Long-termin vitroandin vivodegradation tests of the scaffolds were carried out up to 36 weeks, which support the three-stage degradation process of the polyester porous scaffold and suggest faster degradationin vivothanin vitro. Animal experiments in a rabbit model of articular cartilage injury were conducted. The efficacy of the scaffolds in cartilage regeneration was verified through histological analysis, micro-computed tomography (CT) and biomechanical tests, and the influence of scaffold structures (bilayerversussingle layer) onin vivotissue regeneration was examined. This study has illustrated that the wet 3D printing is an alternative approach to biofabricate tissue engineering porous scaffolds based on biodegradable polymers.

A Double-Expanded Polytetrafluoroethylene Fabrication Method for Increased Mechanical Compliance in Tubular Vascular Graft Applications

A novel manufacturing technique has been developed to enhance the compliance of expanded polytetrafluoroethylene (ePTFE) for vascular graft applications. This new method involves modifying the existing processing procedures by introducing an additional expansion step while using a lower temperature during the first expansion stage. The new process results in the production of highly compliant ePTFE grafts without the need for supplementary additives or inherent material alterations. Tensile testing in both the longitudinal and circumferential directions as well as cyclical tensile testing were conducted to characterize the mechanical properties of double-expanded ePTFE grafts prepared using varying expansion ratios. The double-expanded ePTFE grafts consistently outperformed the prevailing, single-expanded counterparts in both tensile stress tests and cyclical assessments of its elastic compliance. Notably, the double-expanded ePTFE samples exhibited the desirable, biomimetic "toe-region" and an elastic strain capacity of up to 50%, comparable to native vascular materials. Scanning electron microscopy (SEM) imaging was used to examine the morphological characteristics of the wavy fibers within the double-expanded PTFE samples, which contributed to the enhanced compliance that is needed for vascular graft applications.

In vitro and in vivo degradation, biocompatibility and bone repair performance of strontium-doped montmorillonite coating on Mg-Ca alloy

Poor bone growth remains a challenge for degradable bone implants. Montmorillonite and strontium were selected as the carrier and bone growth promoting elements to prepare strontium-doped montmorillonite coating on Mg-Ca alloy. The surface morphology and composition were characterized by SEM, EDS, XPS, FT-IR and XRD. The hydrogen evolution experiment and electrochemical test results showed that the Mg-Ca alloy coated with Sr-MMT coating possessed optimal corrosion resistance performance. Furthermore, in vitro studies on cell activity, ALP activity, and cell morphology confirmed that Sr-MMT coating had satisfactory biocompatibility, which can significantly avail the proliferation, differentiation, and adhesion of osteoblasts. Moreover, the results of the 90-day implantation experiment in rats indicated that, the preparation of Sr-MMT coating effectively advanced the biocompatibility and bone repair performance of Mg-Ca alloy. In addition, The Osteogenic ability of Sr-MMT coating may be due to the combined effect of the precipitation of Si4+ and Sr2+ in Sr-MMT coating and the dissolution of Mg2+ and Ca2+ during the degradation of Mg-Ca alloy. By using coating technology, this study provides a late-model strategy for biodegradable Mg alloys with good corrosion resistance, biocompatibility. This new material will bring more possibilities in bone repair.

Adaptation process of decellularized vascular grafts as hemodialysis access in vivo

Arteriovenous grafts (AVGs) have emerged as the preferred option for constructing hemodialysis access in numerous patients. Clinical trials have demonstrated that decellularized vascular graft exhibits superior patency and excellent biocompatibility compared to polymer materials; however, it still faces challenges such as intimal hyperplasia and luminal dilation. The absence of suitable animal models hinders our ability to describe and explain the pathological phenomena above and in vivo adaptation process of decellularized vascular graft at the molecular level. In this study, we first collected clinical samples from patients who underwent the construction of dialysis access using allogeneic decellularized vascular graft, and evaluated their histological features and immune cell infiltration status 5 years post-transplantation. Prior to the surgery, we assessed the patency and intimal hyperplasia of the decellularized vascular graft using non-invasive ultrasound. Subsequently, in order to investigate the in vivo adaptation of decellularized vascular grafts in an animal model, we attempted to construct an AVG model using decellularized vascular grafts in a small animal model. We employed a physical-chemical-biological approach to decellularize the rat carotid artery, and histological evaluation demonstrated the successful removal of cellular and antigenic components while preserving extracellular matrix constituents such as elastic fibers and collagen fibers. Based on these results, we designed and constructed the first allogeneic decellularized rat carotid artery AVG model, which exhibited excellent patency and closely resembled clinical characteristics. Using this animal model, we provided a preliminary description of the histological features and partial immune cell infiltration in decellularized vascular grafts at various time points, including Day 7, Day 21, Day 42, and up to one-year post-implantation. These findings establish a foundation for further investigation into the in vivo adaptation process of decellularized vascular grafts in small animal model.

Research on triamcinolone-loaded thermosensitive chitosan hydrogels for preventing esophageal stricture induced by endoscopic submucosal dissection

Early-stage esophageal cancer is primarily treated by endoscopic submucosal dissection (ESD). However, extensive mucosal dissection creates a significant risk of postoperative esophageal stricture. Clinically, postoperative stricture can be prevented by glucocorticoids; however, there are drawbacks to both systemic and local administration of glucocorticoids, and improving drug administration methods is crucial. In this study, we developed a chitosan-based thermosensitive hydrogel for triamcinolone (TA) delivery. Our results indicated that the hydrogel remains liquid at low temperatures and can be injected into the esophageal wound site through an endoscopic biopsy channel. Upon reaching body temperature, the hydrogel undergoes spontaneous gelation and firmly adheres to the wound surface. The liquid phase enables convenient and precise delivery, while the gel phase achieves remarkable adhesion, tensile strength, and resistance to degradation. Moreover, the hydrogel exhibited an extended release duration of >10 days when loaded with a 10 mg dose. In vitro studies revealed that the hydrogel suppresses the proliferation and fibrogenesis of human scar fibroblasts (HKF). In a rat skin dermal defect model, the hydrogel attenuated keloid formation during the healing process. Consequently, the chitosan-based thermosensitive hydrogel developed in this study for triamcinolone delivery may be an effective tool for preventing post-ESD esophageal stricture.

Efficacy and safety of a submucosal injection solution of sodium alginate for endoscopic resection in a porcine model

Endoscopic resection techniques require the use of submucosal injection. Normal saline and sodium hyaluronate solutions are mainly used for this purpose, but an ideal solution has not yet been developed. The aim of this study was to assess a new solution, MC-003-a novel submucosal injection solution developed with sodium alginate as the main ingredient. Normal saline, a commercial sodium hyaluronate solution (Endo-Ease), and MC-003 were examined. A total of 18 gastric submucosal cushions were created in the stomachs of six pigs. The height of mucosal elevation was measured sequentially using endoscopic sonography. After euthanizing the animals either 2 h or 5 days after the procedure, pathologic examination was performed for each injection site. Although not statistically significant over the entire study period, MC-003 showed a superior result to normal saline and an equivalent result to Endo-Ease in the submucosal cushion height and its rate of decrease. There were no adverse outcomes after injection of the three solutions and there was no pathologically identified detrimental change in the resected specimens. MC-003 creates a sufficient submucosal fluid cushion without apparent tissue damage. It can be considered as an effective submucosal injection material.

Cancer cell response to extrinsic and intrinsic mechanical cue: opportunities for tumor apoptosis strategies

Increasing studies have revealed the importance of mechanical cues in tumor progression, invasiveness and drug resistance. During malignant transformation, changes manifest in either the mechanical properties of the tissue or the cellular ability to sense and respond to mechanical signals. The major focus of the review is the subtle correlation between mechanical cues and apoptosis in tumor cells from a mechanobiology perspective. To begin, we focus on the intracellular force, examining the mechanical properties of the cell interior, and outlining the role that the cytoskeleton and intracellular organelle-mediated intracellular forces play in tumor cell apoptosis. This article also elucidates the mechanisms by which extracellular forces guide tumor cell mechanosensing, ultimately triggering the activation of the mechanotransduction pathway and impacting tumor cell apoptosis. Finally, a comprehensive examination of the present status of the design and development of anti-cancer materials targeting mechanotransduction is presented, emphasizing the underlying design principles. Furthermore, the article underscores the need to address several unresolved inquiries to enhance our comprehension of cancer therapeutics that target mechanotransduction.

Application of metal-organic frameworks-based functional composite scaffolds in tissue engineering

With the rapid development of materials science and tissue engineering, a variety of biomaterials have been used to construct tissue engineering scaffolds. Due to the performance limitations of single materials, functional composite biomaterials have attracted great attention as tools to improve the effectiveness of biological scaffolds for tissue repair. In recent years, metal-organic frameworks (MOFs) have shown great promise for application in tissue engineering because of their high specific surface area, high porosity, high biocompatibility, appropriate environmental sensitivities and other advantages. This review introduces methods for the construction of MOFs-based functional composite scaffolds and describes the specific functions and mechanisms of MOFs in repairing damaged tissue. The latest MOFs-based functional composites and their applications in different tissues are discussed. Finally, the challenges and future prospects of using MOFs-based composites in tissue engineering are summarized. The aim of this review is to show the great potential of MOFs-based functional composite materials in the field of tissue engineering and to stimulate further innovation in this promising area.

Advances in functional coatings on biliary stents

Biliary stenting is an important interventional method for the prevention and treatment of biliary tract diseases. However, complications, such as postoperative biliary infection and restenosis, frequently occur due to the extensive scope of the biliary system and the complex composition of bile. The combination of coating technology and biliary stents is expected to bring new approaches to the solution of these problems. The cutting-edge advance on functional coatings on biliary stents is reviewed from seven perspectives: anticorrosion, -bacterial, -tumor, stone-dissolving, X-ray visibility, antistent migration and functional composite coatings. The development trend is also discussed. Overall, the performance of the numerous functional coatings for various purposes is generally up to expectations, but the balance between the medications' effectiveness and their safety needs to be further adjusted. Many contemporary investigations have advanced to the level of animal experiments, offering crucial fundamental assurance for broader human studies. The combination of biliary stents and functional coatings is an innovative idea with great potential for future development.

Fe-Zn alloy, a new biodegradable material capable of reducing ROS and inhibiting oxidative stress

Fe-based biodegradable materials have attracted significant attention due to their exceptional mechanical properties and favorable biocompatibility. Currently, research on Fe-based materials mainly focuses on regulating the degradation rate. However, excessive release of Fe ions during material degradation will induce the generation of reactive oxygen species (ROS), leading to oxidative stress and ferroptosis. Therefore, the control of ROS release and the improvement of biocompatibility for Fe-based materials are very important. In this study, new Fe-Zn alloys were prepared by electrodeposition with the intention of using Zn as an antioxidant to reduce oxidative damage during alloy degradation. Initially, the impact of three potential degradation ions (Fe2+, Fe3+, Zn2+) from the Fe-Zn alloy on human endothelial cell (EC) activity and migration ability was investigated. Subsequently, cell adhesion, cell activity, ROS production and DNA damage were assessed at various locations surrounding the alloy. Finally, the influence of different concentrations of Zn2+ in the medium on cell viability and ROS production was evaluated. High levels of ROS exhibited evident toxic effects on ECs and promoted DNA damage. As an antioxidant, Zn2+ effectively reduced ROS production around Fe and improved the cell viability on its surface at a concentration of 0.04 mmol/l. These findings demonstrate that Fe-Zn alloy can attenuate the ROS generated from Fe degradation thereby enhancing cytocompatibility.