Hierarchically Patterned Polydopamine-Containing Membranes for Periodontal Tissue Engineering

Hierarchical Chitin Nanocrystal-Based 3D Printed Dual-Layer Membranes Hydrogels: A Dual Drug Delivery Nano-Platform for Periodontal Tissue Regeneration

Periodontitis, a prevalent chronic inflammatory disease caused by bacteria, poses a significant challenge to current treatments by merely slowing their progression. Herein, we propose an innovative solution in the form of hierarchical nanostructured 3D printed bilayer membranes that serve as dual-drug delivery nanoplatforms and provide scaffold function for the regeneration of periodontal tissue. Nanocomposite hydrogels were prepared by combining lipid nanoparticle-loaded grape seed extract and simvastatin, as well as chitin nanocrystals, which were then 3D printed into a bilayer membrane that possesses antimicrobial properties and multiscale porosity for periodontal tissue regeneration. The constructs exhibited excellent mechanical properties by adding chitin nanocrystals and provided a sustained release of distinct drugs over 24 days. We demonstrated that the bilayer membranes are cytocompatible and have the ability to induce bone-forming markers in human mesenchymal stem cells, while showing potent antibacterial activity against pathogens associated with periodontitis. In vivo studies further confirmed the efficacy of bilayer membranes in enhancing alveolar bone regeneration and reducing inflammation in a periodontal defect model. This approach suggests promising avenues for the development of implantable constructs that not only combat infections, but also promote the regeneration of periodontal tissue, providing valuable insights into advanced periodontitis treatment strategies.

Nanomaterials: innovative approaches for addressing key objectives in periodontitis treatment

Periodontitis is a chronic inflammatory disease primarily caused by dental plaque, which is a significant global public health concern due to its high prevalence and severe impact on oral, and even systemic diseases. The current therapeutic plan focuses on three objectives: pathogenic bacteria inhibition, inflammation control, and osteogenic differentiation induction. Existing treatments still have plenty of drawbacks, thus, there is a pressing need for novel methods to achieve more effective treatment effects. Nanomaterials, as emerging materials, have been proven to exert their inherent biological properties or serve as stable drug delivery platforms, which may offer innovative solutions in periodontitis treatment. Nanomaterials utilized in periodontitis treatment fall into two categories, organic and inorganic nanomaterials. Organic nanomaterials are known for their biocompatibility and their potential to promote tissue regeneration and cell functions, including natural and synthetic polymers. Inorganic nanomaterials, such as metal, oxides, and mesoporous silica nanoparticles, exhibit unique physicochemical properties that make them suitable as antibacterial agents and drug delivery platforms. The inorganic nanosurface provides terrain induction for cell migration and osteogenic regeneration at defect sites by introducing different surface morphologies. Inorganic nanomaterials also play a role in antibacterial photodynamic therapy (aPDT) for eliminating pathogenic bacteria in the oral cavity. In this review, we will introduce multiple forms and applications of nanomaterials in periodontitis treatment and focus on their roles in addressing the key therapeutic objectives, to emphasize their promising future in achieving more effective and patient-friendly approaches toward periodontal tissue regeneration and overall health.

Polydopamine Applications in Biomedicine and Environmental Science

This manuscript explores the multifaceted applications of polydopamine (PDA) across various scientific and industrial domains. It covers the chemical aspects of PDA and its potential in bone tissue engineering, implant enhancements, cancer treatment, and nanotechnology. The manuscript investigates PDA's roles in tissue engineering, cell culture technologies, surface modifications, drug delivery systems, and sensing techniques. Additionally, it highlights PDA's contributions to microfabrication, nanoengineering, and environmental applications. Through detailed testing and assessment, the study identifies limitations in PDA-related research, such as synthesis complexity, incomplete mechanistic understanding, and biocompatibility variability. It also proposes future research directions aimed at improving synthesis techniques, expanding biomedical applications, and enhancing sensing technologies to optimize PDA's efficacy and scalability.

Antibacterial and antioxidant phlorizin-loaded nanofiber film effectively promotes the healing of burn wounds

Burns usually result in damage and loss of skin forming irregular wound wounds. The lack of skin tissue protection makes the wound site highly vulnerable to bacterial infections, hindering the healing process. However, commonly used wound dressings do not readily provide complete coverage of irregular wounds compared to regular wounds. Therefore, there is an urgent need to prepare a wound dressing with high antimicrobial efficacy for the administration of drugs to irregular wounds. In this study, a chitosan (CS)/polyvinylpyrrolidone (PVP) composite nanofiber membrane (CS/PVP/Phlorizin) loaded with root bark glycosides (Phlorizin) was developed using an electrostatic spinning technique. The incorporation of phlorizin, a natural antioxidant, into the fiber membranes notably boosted their antimicrobial and antioxidant capabilities, along with demonstrating excellent hydrophilic characteristics. In vitro cellular experiments showed that CS/PVP/Phlorizin increased Hacat cell viability with the presence of better cytocompatibility. In scald wound healing experiments, Phlorizin-loaded nanofibrous membranes significantly promoted re-epithelialization and angiogenesis at the wound site, and reduced the inflammatory response at the wound site. Therefore, the above results indicate that this nanofiber membrane is expected to be an ideal dressing for burn wounds.

Fabrication of Bioresorbable Barrier Membranes from Gelatin/Poly(4-Hydroxybutyrate) (P4HB)

Dental implant surgery is a procedure that replaces damaged or missing teeth with an artificial implant. During this procedure, guided bone regeneration (GBR) membranes are commonly used to inhibit the migration of epithelium and GBR at the surgical sites. Due to its biodegradability, good biocompatibility, and unique biological properties, gelatin (GT) is considered a suitable candidate for guiding periodontal tissue regeneration. However, GT-based membranes come with limitations, such as poor mechanical strength and mismatched degradation rates. To confront this challenge, a series of GT/poly(4-hydroxybutyrate) (P4HB) composite membranes are fabricated through electrospinning technology. The morphology, composition, wetting properties, mechanical properties, biocompatibility, and in vivo biodegradability of the as-prepared composite membranes are carefully characterized. The results demonstrate that all the membranes present excellent biocompatibility. Moreover, the in vivo degradation rate of the membranes can be manipulated by changing the ratio of GT and P4HB. The results indicate that the optimized GT/P4HB membranes with a high P4HB content (75%) may be suitable for periodontal tissue engineering because of their good mechanical properties and biodegradation rate compatible with tissue growth.

Nanoparticles in Periodontitis Therapy: A Review of the Current Situation

Periodontitis is a disease of inflammation that affects the tissues supporting the periodontium. It is triggered by an immunological reaction of the gums to plaque, which leads to the destruction of periodontal attachment structures. Periodontitis is one of the most commonly recognized dental disorders in the world and a major factor in the loss of adult teeth. Scaling and root planing remain crucial for managing patients with persistent periodontitis. Nevertheless, exclusive reliance on mechanical interventions like periodontal surgery, extractions, and root planning is insufficient to halt the progression of periodontitis. In response to the problem of bacterial resistance, some researchers are committed to finding alternative therapies to antibiotics. In addition, some scholars focus on finding new materials to provide a powerful microenvironment for periodontal tissue regeneration and promote osteogenic repair. Nanoparticles possess distinct therapeutic qualities, including exceptional antibacterial, anti-inflammatory, and antioxidant properties, immunomodulatory capacities, and the promotion of bone regeneration ability, which made them can be used for the treatment of periodontitis. However, there are many problems that limit the clinical translation of nanoparticles, such as toxic accumulation in cells, poor correlation between in vitro and in vivo, and poor animal-to-human transmissibility. In this paper, we review the present researches on nanoparticles in periodontitis treatment from the perspective of three main categories: inorganic nanoparticles, organic nanoparticles, and nanocomposites (including nanofibers, hydrogels, and membranes). The aim of this review is to provide a comprehensive and recent update on nanoparticles-based therapies for periodontitis. The conclusion section summarizes the opportunities and challenges in the design and clinical translation of nanoparticles for the treatment of periodontitis.

Bioinspired core-shell nanofiber drug-delivery system modulates osteogenic and osteoclast activity for bone tissue regeneration

Osteogenic-osteoclast coupling processes play a crucial role in bone regeneration. Recently, strategies that focus on multi-functionalized implant surfaces to enhance the healing of bone defects through the synergistic regulation of osteogenesis and osteoclastogenesis is still a challenging task in the field of bone tissue engineering. The aim of this study was to create a dual-drug release-based core-shell nanofibers with the intent of achieving a time-controlled release to facilitate bone regeneration. We fabricated core-shell P/PCL nanofibers using coaxial electrospinning, where alendronate (ALN) was incorporated into the core layer and hydroxyapatite (HA) into shell. The surface of the nanofiber construct was further modified with mussel-derived polydopamine (PDA) to induce hydrophilicity and enhance cell interactions. Surface characterizations confirmed the successful synthesis of PDA@PHA/PCL-ALN nanofibers endowed with excellent mechanical strength (20.02 ± 0.13 MPa) and hydrophilicity (22.56°), as well as the sustained sequential release of ALN and Ca ions. In vitro experiments demonstrated that PDA-functionalized core-shell PHA/PCL-ALN scaffolds possessed excellent cytocompatibility, enhanced cell adhesion and proliferation, alkaline phosphatase activity and osteogenesis-related genes. In addition to osteogenesis, the engineered scaffolds also significantly reduced osteoclastogenesis, such as tartrate-resistant acid phosphatase activity and osteoclastogenesis-related gene expression. After 12-week of implantation, it was observed that PDA@PHA/PCL-ALN nanofiber scaffolds, in a rat cranial defect model, significantly promoted bone repair and regeneration. Microcomputed tomography, histological examination, and immunohistochemical analysis collectively demonstrated that the PDA-functionalized core-shell PHA/PCL-ALN scaffolds exhibited exceptional osteogenesis-inducing and osteoclastogenesis-inhibiting effects. Finally, it may be concluded from our results that the bio-inspired surface-functionalized multifunctional, biomimetic and controlled release core-shell nanofiber provides a promising strategy to facilitate bone healing.

Functionalizable bacterial cellulose composite membrane for guided tissue regeneration

This research aims to develop guided tissue regeneration (GTR) membranes from bacterial cellulose (BC), a natural polysaccharide-based biopolymer. A double-layered BC composite membrane was prepared by coating the BC membrane with mixed carboxymethyl cellulose/poly(ethylene oxide) (CMC/PEO) fibers via electrospinning. The CMC/PEO-BC membranes were then characterized for their chemical and physical characteristics. The 8 % (wt/v) CMC/PEO (1:1) aqueous solution yielded well-defined electrospun CMC/PEO nanofibers (125 ± 10 nm) without beads. The CMC/PEO-BC membranes exhibited good mechanical and swelling properties as well as good cytocompatibility against human periodontal ligament cells (hPDLs). Its functionalizability via carboxyl entities in CMC was tested using the calcium-binding domain of plant-derived recombinant human osteopontin (p-rhOPN-C122). As evaluated by enzyme-linked immunosorbent assay, a 98-99 % immobilization efficiency was achieved in a concentration-dependent manner over an applied p-rhOPN-C122 concentration range of 7.5-30 ng/mL. The biological function of the membrane was assessed by determining the expression levels of osteogenic-related gene transcripts using quantitative real-time reverse-transcriptase polymerase chain reaction. Mineralization assay indicated that the p-rhOPN-C122 immobilized CMC/PEO-BC membrane promoted hPDLs osteogenic differentiation. These results suggested that the developed membrane could serve as a promising GTR membrane for application in bone tissue regeneration.

The antibacterial and hemostatic curdlan hydrogel-loading epigallocatechin gallate for facilitating the infected wound healing

The infected wounds pose one of the major threats to human health today. To address this issue, it is necessary to develop innovative wound dressings with superior antibacterial activity and other properties. Due to its potent antibacterial, antioxidant, and immune-boosting properties, epigallocatechin gallate (EGCG) has been widely utilized. In this study, a multifunctional curdlan hydrogel loading EGCG (Cur-EGCGH3) was designed. Cur-EGCGH3 exhibited excellent physicochemical properties, good biocompatibility, hemostatic, antibacterial, and antioxidant activities. Also, ELISA data showed that Cur-EGCGH3 stimulated macrophages to secrete pro-inflammatory and pro-regenerative cytokines. Cell scratch results indicated that Cur-EGCGH3 promoted the migration of NIH3T3 and HUVECs. In vivo experiments confirmed that Cur-EGCGH3 could inhibit bacterial infection of the infected wounds, accelerate hemostasis, and promote epithelial regeneration and collagen deposition. These results demonstrated that Cur-EGCGH3 holds promise for promoting healing of the infected wounds.

Nanomedomics

Nanomaterials have attractive physicochemical properties. A variety of nanomaterials such as inorganic, lipid, polymers, and protein nanoparticles have been widely developed for nanomedicine via chemical conjugation or physical encapsulation of bioactive molecules. Superior to traditional drugs, nanomedicines offer high biocompatibility, good water solubility, long blood circulation times, and tumor-targeting properties. Capitalizing on this, several nanoformulations have already been clinically approved and many others are currently being studied in clinical trials. Despite their undoubtful success, the molecular mechanism of action of the vast majority of nanomedicines remains poorly understood. To tackle this limitation, herein, this review critically discusses the strategy of applying multiomics analysis to study the mechanism of action of nanomedicines, named nanomedomics, including advantages, applications, and future directions. A comprehensive understanding of the molecular mechanism could provide valuable insight and therefore foster the development and clinical translation of nanomedicines.

Degradable biomedical elastomers: paving the future of tissue repair and regenerative medicine

Degradable biomedical elastomers (DBE), characterized by controlled biodegradability, excellent biocompatibility, tailored elasticity, and favorable network design and processability, have become indispensable in tissue repair. This review critically examines the recent advances of biodegradable elastomers for tissue repair, focusing mainly on degradation mechanisms and evaluation, synthesis and crosslinking methods, microstructure design, processing techniques, and tissue repair applications. The review explores the material composition and cross-linking methods of elastomers used in tissue repair, addressing chemistry-related challenges and structural design considerations. In addition, this review focuses on the processing methods of two- and three-dimensional structures of elastomers, and systematically discusses the contribution of processing methods such as solvent casting, electrostatic spinning, and three-/four-dimensional printing of DBE. Furthermore, we describe recent advances in tissue repair using DBE, and include advances achieved in regenerating different tissues, including nerves, tendons, muscle, cardiac, and bone, highlighting their efficacy and versatility. The review concludes by discussing the current challenges in material selection, biodegradation, bioactivation, and manufacturing in tissue repair, and suggests future research directions. This concise yet comprehensive analysis aims to provide valuable insights and technical guidance for advances in DBE for tissue engineering.

Wet adhesive hydrogels based on niobium carbide for experimental research of oral mucosal impairment

Oral mucosal impairment is a prevalent oral disease that frequently causes pain for patients. Conventional treatments have limited effectiveness and can cause adverse reactions. Furthermore, the moist and dynamic nature of the oral mucosal environment makes persistent adherence of conventional materials challenging, which can affect treatment efficacy. In this study, we investigated the potential of a NbC/TA-GelMA hydrogel system, where niobium carbide (NbC) and tannic acid (TA) were added to gelatin methacryloyl (GelMA), for repairing oral mucosal impairment. The wet adhesion properties of NbC/TA-GelMA hydrogels were confirmed by the inclusion of TA with a catechol-rich group. In addition, the photothermal effect of NbC/TA-GelMA hydrogel under near-infrared light, synergizing with TA, provided sustained antibacterial action. Furthermore, the NbC/TA-GelMA hydrogel effectively healed damaged oral mucosa of rats.

Programmable Electro-Assembly of Collagen: Constructing Porous Janus Films with Customized Dual Signals for Immunomodulation and Tissue Regeneration in Periodontitis Treatment

Currently available guided bone regeneration (GBR) films lack active immunomodulation and sufficient osteogenic ability- in the treatment of periodontitis, leading to unsatisfactory treatment outcomes. Challenges remain in developing simple, rapid, and programmable manufacturing methods for constructing bioactive GBR films with tailored biofunctional compositions and microstructures. Herein, the controlled electroassembly of collagen under the salt effect is reported, which enables the construction of porous films with precisely tunable porous structures (i.e., porosity and pore size). In particular, bioactive salt species such as the anti-inflammatory drug diclofenac sodium (DS) can induce and customize porous structures while enabling the loading of bioactive salts and their gradual release. Sequential electro-assembly under pre-programmed salt conditions enables the manufacture of a Janus composite film with a dense and DS-containing porous layer capable of multiple functions in periodontitis treatment, which provides mechanical support, guides fibrous tissue growth, and acts as a barrier preventing its penetration into bone defects. The DS-containing porous layer delivers dual bio-signals through its morphology and the released DS, inhibiting inflammation and promoting osteogenesis. Overall, this study demonstrates the potential of electrofabrication as a customized manufacturing platform for the programmable assembly of collagen for tailored functions to adapt to specific needs in regenerative medicine.

Development of a rapid-shaping and user-friendly membrane with long-lasting space maintenance for guided bone regeneration

The success of guided bone regeneration (GBR) surgery depends largely on the use of GBR membranes to maintain space for bone regeneration and prevent soft tissue ingrowth. However, currently available commercial degradable GBR membranes are often limited by poor space maintenance ability and require additional suture or nail for fixation. To overcome these limitations, we developed a rapid-shaping, adhesive, and user-friendly GBR membrane (PLGA film-PGN) with long-lasting space maintenance by immersing an electrospun poly(lactide-co-glycolic acid) film in a photo-crosslinkable hydrogel composed of polyethylene glycol diacrylate, gelatin methacryloyl, and nanosilicate (PGN). The PGN hydrogel significantly improved the mechanical strength of the PLGA film-PGN and endowed it with plasticity and adhesive properties, making it more maneuverable. The maximum bending force that the PLGA film-PGN could withstand was over 55 times higher than that of the HEAL ALL film (a commonly used commercial GBR membrane). PLGA film-PGN also promoted the proliferation and osteogenic differentiation of rBMSCs. According to a critical-size rat calvarial defect model, PLGA film-PGN maintained the space within the defect area and significantly enhanced bone formation 4 weeks after the surgery. To conclude, the study provided a novel perspective on GBR membrane design and the multifunctional PLGA film-PGN membrane demonstrated great potential for bone defect reconstruction.

A multifunctional quercetin/polycaprolactone electrospun fibrous membrane for periodontal bone regeneration

Image 1.

Aptamer Renaissance for Neurochemical Biosensing

Unraveling the complexities of brain function, which is crucial for advancing human health, remains a grand challenge. This endeavor demands precise monitoring of small molecules such as neurotransmitters, the chemical messengers in the brain. In this Perspective, we explore the potential of aptamers, selective synthetic bioreceptors integrated into electronic affinity platforms to address limitations in neurochemical biosensing. We emphasize the importance of characterizing aptamer thermodynamics and target binding to realize functional biosensors in biological systems. We focus on two label-free affinity platforms spanning the micro- to nanoscale: field-effect transistors and nanopores. Integration of well-characterized structure-switching aptamers overcame nonspecific binding, a challenge that has hindered the translation of biosensors from the lab to the clinic. In a transformative era driven by neuroscience breakthroughs, technological innovations, and multidisciplinary collaborations, an aptamer renaissance holds the potential to bridge technological gaps and reshape the landscape of diagnostics and neuroscience.

Bone Scaffold Materials in Periodontal and Tooth-supporting Tissue Regeneration: A Review

BACKGROUND AND OBJECTIVES

Periodontium is an important tooth-supporting tissue composed of both hard (alveolar bone and cementum) and soft (gingival and periodontal ligament) sections. Due to the multi-tissue architecture of periodontium, reconstruction of each part can be influenced by others. This review focuses on the bone section of the periodontium and presents the materials used in tissue engineering scaffolds for its reconstruction.

MATERIALS AND METHODS

The following databases (2015 to 2021) were electronically searched: ProQuest, EMBASE, SciFinder, MRS Online Proceedings Library, Medline, and Compendex. The search was limited to English-language publications and in vivo studies.

RESULTS

Eighty-three articles were found in primary searching. After applying the inclusion criteria, seventeen articles were incorporated into this study.

CONCLUSION

In complex periodontal defects, various types of scaffolds, including multilayered ones, have been used for the functional reconstruction of different parts of periodontium. While there are some multilayered scaffolds designed to regenerate alveolar bone/periodontal ligament/cementum tissues of periodontium in a hierarchically organized construct, no scaffold could so far consider all four tissues involved in a complete periodontal defect. The progress and material considerations in the regeneration of the bony part of periodontium are presented in this work to help investigators develop tissue engineering scaffolds suitable for complete periodontal regeneration.

In Vitro Investigation of Gelatin/Polycaprolactone Nanofibers in Modulating Human Gingival Mesenchymal Stromal Cells

The aesthetic constancy and functional stability of periodontium largely depend on the presence of healthy mucogingival tissue. Soft tissue management is crucial to the success of periodontal surgery. Recently, synthetic substitute materials have been proposed to be used for soft tissue augmentation, but the tissue compatibility of these materials needs to be further investigated. This study aims to assess the in vitro responses of human gingival mesenchymal stromal cells (hG-MSCs) cultured on a Gelatin/Polycaprolactone prototype (GPP) and volume-stable collagen matrix (VSCM). hG-MSCs were cultured onto the GPP, VSCM, or plastic for 3, 7, and 14 days. The proliferation and/or viability were measured by cell counting kit-8 assay and resazurin-based toxicity assay. Cell morphology and adhesion were evaluated by microscopy. The gene expression of collagen type I, alpha1 (COL1A1), α-smooth muscle actin (α-SMA), fibroblast growth factor (FGF-2), vascular endothelial growth factor A (VEGF-A), transforming growth factor beta-1 (TGF-β1), focal adhesion kinase (FAK), integrin beta-1 (ITG-β1), and interleukin 8 (IL-8) was investigated by RT-qPCR. The levels of VEGF-A, TGF-β1, and IL-8 proteins in conditioned media were tested by ELISA. GPP improved both cell proliferation and viability compared to VSCM. The cells grown on GPP exhibited a distinct morphology and attachment performance. COL1A1, α-SMA, VEGF-A, FGF-2, and FAK were positively modulated in hG-MSCs on GPP at different investigation times. GPP increased the gene expression of TGF-β1 but had no effect on protein production. The level of ITG-β1 had no significant changes in cells seeded on GPP at 7 days. At 3 days, notable differences in VEGF-A, TGF-β1, and α-SMA expression levels were observed between cells seeded on GPP and those on VSCM. Meanwhile, GPP showed higher COL1A1 expression compared to VSCM after 14 days, whereas VSCM demonstrated a more significant upregulation in the production of IL-8. Taken together, our data suggest that GPP electrospun nanofibers have great potential as substitutes for soft tissue regeneration in successful periodontal surgery.

Research progress of biomimetic materials in oral medicine

Biomimetic materials are able to mimic the structure and functional properties of native tissues especially natural oral tissues. They have attracted growing attention for their potential to achieve configurable and functional reconstruction in oral medicine. Though tremendous progress has been made regarding biomimetic materials, significant challenges still remain in terms of controversy on the mechanism of tooth tissue regeneration, lack of options for manufacturing such materials and insufficiency of in vivo experimental tests in related fields. In this review, the biomimetic materials used in oral medicine are summarized systematically, including tooth defect, tooth loss, periodontal diseases and maxillofacial bone defect. Various theoretical foundations of biomimetic materials research are reviewed, introducing the current and pertinent results. The benefits and limitations of these materials are summed up at the same time. Finally, challenges and potential of this field are discussed. This review provides the framework and support for further research in addition to giving a generally novel and fundamental basis for the utilization of biomimetic materials in the future.

Synthesis, Characterization, and Induced Osteogenic Differentiation Effect of Collagen Membranes Functionalized by Polydopamine/Graphene Oxide for Bone Tissue Engineering

Collagen is one of the most common natural absorbable polymers, which is widely used as a barrier membrane in biomedical fields due to its many desirable biological properties. However, absorbable membranes such as collagen have their own disadvantages such as unpredictable degradation rates, poor rigidity leading to tissue collapse, and limited osteogenic properties and cell adhesion. In this study, a modified collagen membrane with a polydopamine-graphene oxide (PDA/GO) complex was synthesized to improve the characteristics of collagen for bone tissue engineering. The successful synthesis of PDA/GO on collagen membranes was verified using X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The wettability of PDA/GO-modified collagen membranes was considerably improved based on the characterization by water contact angle compared to the uncoated membranes and surface coatings solely by either PDA or GO. The modified PDA/GO coating also enhanced the mechanical properties such as tensile strength and biodegradation rate of collagen membranes. In addition, the PDA/GO coating effectively enhanced the biocompatibility of collagen membranes as verified by the enhanced proliferation and adhesion of human bone marrow stem cells (hBMSCs). Additionally, the effects of PDA/GO coating on the osteogenic differentiation of hBMSCs on collagen membranes were investigated through alkaline phosphatase (ALP) activity and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The PDA/GO coating on collagen membranes resulted in a significant increase in osteogenic properties compared with the uncoated collagen membranes. According to the results of the current study, the combination of PDA and GO-modified collagen membranes could be used for bone tissue engineering and biomedical applications.

CGRP-Loaded Porous Microspheres Protect BMSCs for Alveolar Bone Regeneration in the Periodontitis Microenvironment

Periodontitis is a prevalent dental disease marked by progressive destruction of tooth-supporting tissues, and the recovery of bone defects after periodontitis remains challenging. Although stem cell-based therapy is a promising treatment for periodontal tissue regeneration, the function of mesenchymal stem cells is constantly impaired by the inflammatory microenvironment, leading to compromised treatment outcomes. Herein, calcitonin gene-related peptide (CGRP)-loaded porous microspheres (PMs) are prepared to protect bone marrow mesenchymal stem cells (BMSCs) against inflammatory mediators in periodontitis. The released CGRP can effectively ameliorate the inflammation-induced dysfunction of BMSCs, which may involve suppressing the ROS (reactive oxygen species)/NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3)/Caspase-1 (CASP1) pathway. Moreover, the porous architecture of PMs provides effective cell-carrying capacity and physical protection for BMSCs during transplantation. In vivo experiments demonstrate that CGRP/BMSC-loaded PMs can effectively inhibit inflammation and improve osteogenic activity, resulting in better periodontal bone regeneration. This study focuses on the protection of stem cell function in the inflammatory microenvironment, which is important for stem cell-mediated tissue regeneration and repair under inflammatory conditions.

Tooth-derived stem cells integrated biomaterials for bone and dental tissue engineering

Recent years have seen the emergence of tissue engineering strategies as a means to overcome some of the limits of conventional medical treatment. A biomaterial with tailored physio-chemical characteristics is used in this sophisticated method to transport stem cells and growth factors/bioactive substances, or to attract local endogenous cells, enabling new tissue formation. Biomaterials might serve as a biomimetic structure inspired by the natural milieu, assisting the cells in establishing their natural relationships. Such a method would benefit from having ready access to an abundant reservoir of stem cells with strong tissue regeneration capacity, in addition to using biological compatible material to promote new tissue creation. Teeth may have a plethora of self-renewing, multipotent mesenchymal stem cell (MSC) populations. Recent advancements and promising directions for cell transplantation and homing techniques using dental MSCs for tissue regeneration are discussed in this review paper. Overall, this research paints a picture of the present landscape of new approaches to using tooth-derived MSCs in conjunction with biomaterials and bioactive substances for tissue regeneration.

Janus functional electrospun polyurethane fibrous membranes for periodontal tissue regeneration

The guided tissue regeneration (GTR) technique with GTR membranes is an efficient method for repairing periodontal defects. Conventional periodontal membranes act as physical barriers that resist the growth of fibroblasts, epithelial cells, and connective tissue. However, they cannot facilitate the regeneration of periodontal tissue. To address this issue, the exploitation of novel GTR membranes with bioactive functions based on therapeutic requirements is critical. Herein, we exploited a biodegradable bilayer polyurethane fibrous membrane by uniaxial electrostatic spinning to construct two sides with Janus properties by integrating the bioactive molecule dopamine (DA) and antimicrobial Gemini quaternary ammonium salt (QAS). The DA-containing side, located inside the injury, can effectively promote cell adhesion and mesenchymal stem cell growth as well as support mineralization and antioxidant properties, which are beneficial for bone regeneration. The QAS-containing side, located on the outer surface of the injury, endows antibacterial properties and limits fibroblast adhesion and growth on its surface owing to its strong hydrophilicity. An in vivo study demonstrates that the Janus polyurethane fibrous membrane can significantly promote the regeneration of periodontal defects in rats. Owing to its superior mechanical properties and biocompatibility, this polyurethane fibrous membrane has potential applications in the field of periodontal regeneration.

Polydopamine-Mediated Immunomodulatory Patch for Diabetic Periodontal Tissue Regeneration Assisted by Metformin-ZIF System

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

Advances and Prospects in Materials for Craniofacial Bone Reconstruction

The craniofacial region is composed of 23 bones, which provide crucial function in keeping the normal position of brain and eyeballs, aesthetics of the craniofacial complex, facial movements, and visual function. Given the complex geometry and architecture, craniofacial bone defects not only affect the normal craniofacial structure but also may result in severe craniofacial dysfunction. Therefore, the exploration of rapid, precise, and effective reconstruction of craniofacial bone defects is urgent. Recently, developments in advanced bone tissue engineering bring new hope for the ideal reconstruction of the craniofacial bone defects. This report, presenting a first-time comprehensive review of recent advances of biomaterials in craniofacial bone tissue engineering, overviews the modification of traditional biomaterials and development of advanced biomaterials applying to craniofacial reconstruction. Challenges and perspectives of biomaterial development in craniofacial fields are discussed in the end.

Nanosilicate-functionalized nanofibrous membrane facilitated periodontal regeneration potential by harnessing periodontal ligament cell-mediated osteogenesis and immunomodulation

Although various new biomaterials have enriched the methods for periodontal regeneration, their efficacy is still controversial, and the regeneration of damaged support tissue in the periodontium remains challenging. Laponite (LAP) nanosilicate is a layered two-dimensional nanoscale, ultrathin nanomaterial with a unique structure and brilliant biocompatibility and bioactivity. This study aimed to investigate the effects of nanosilicate-incorporated PCL (PCL/LAP) nanofibrous membranes on periodontal ligament cells (PDLCs) in vitro and periodontal regeneration in vivo. A PCL/LAP nanofibrous membrane was fabricated by an electrospinning method. The characterization of PCL/LAP nanofibrous membrane were determined by scanning electron microscopy (SEM), energy dispersive spectrum of X-ray (EDS), inductively coupled plasma mass spectrometry (ICP-MS) and tensile test. The proliferation and osteogenic differentiation of PDLCs on the PCL/LAP nanofibrous membrane were evaluated. A PDLCs and macrophage coculture system was used to explore the immunomodulatory effects of the PCL/LAP nanofibrous membrane. PCL/LAP nanofibrous membrane was implanted into rat calvarial and periodontal defects, and the regenerative potential was evaluated by microcomputed topography (micro-CT) and histological analysis. The PCL/LAP nanofibrous membrane showed good biocompatibility and bioactivity. It enhanced the proliferation and osteogenic differentiation of PDLCs. The PCL/LAP nanofibrous membrane also stimulated anti-inflammatory and pro-remodeling N2 neutrophil formation, regulated inflammatory responses and induced M2 macrophage polarization by orchestrating the immunomodulatory effects of PDLCs. The PCL/LAP nanofibrous membrane promoted rat calvarial defect repair and periodontal regeneration in vivo. LAP nanosilicate-incorporated PCL membrane is capable of mediating osteogenesis and immunomodulation of PDLCs in vitro and accelerating periodontal regeneration in vivo. It could be a promising biomaterial for periodontal regeneration therapy.

Poly-Catecholic Functionalization of Biomolecules for Rapid Gelation, Robust Injectable Bioadhesion, and Near-Infrared Responsiveness

Mussel-inspired catechol-functionalization of degradable natural biomaterials has garnered significant interest as an approach to achieve bioadhesion for sutureless wound closure. However, conjugation capacity in standard coupling reactions, such as carbodiimide chemistry, is limited by low yield and lack of abundant conjugation sites. Here, a simple oxidative polymerization step before conjugation of catechol-carrying molecules (i.e., 3,4-dihydroxy-l-phenylalanine, l-DOPA) as a potential approach to amplify catechol function in bioadhesion of natural gelatin biomaterials is proposed. Solutions of gelatin modified with poly(l-DOPA) moieties (GelDOPA) are characterized by faster physical gelation and increased viscosity, providing better wound control on double-curved tissue surfaces compared to those of l-DOPA-conjugated gelatin. Physical hydrogels treated topically with low concentrations of NaIO4 solutions are crosslinked on-demand via through-thickness diffusion. Poly(l-DOPA) conjugates enhance crosslinking density compared to l-DOPA conjugated gelatin, resulting in lower swelling and enhanced cohesion in physiological conditions. Together with cohesion, more robust bioadhesion at body temperature is achieved by poly(l-DOPA) conjugates, exceeding those of commercial sealants. Further, poly(l-DOPA) motifs introduced photothermal responsiveness via near-infrared (NIR) irradiation for controlled drug release and potential applications in photothermal therapy. The above functionalities, along with antibacterial activity, render the proposed approach an effective biomaterial design strategy for wound closure applications.

Mild Photothermal-Stimulation Based on Injectable and Photocurable Hydrogels Orchestrates Immunomodulation and Osteogenesis for High-Performance Bone Regeneration

A photoactivated bone scaffold integrated with minimally invasive implantation and mild thermal-stimulation capability shows great promise in the repair and regeneration of irregularly damaged bone tissues. Developing multifunctional photothermal biomaterials that can simultaneously serve as both controllable thermal stimulators and biodegradable engineering scaffolds for integrated immunomodulation, infection therapy, and impaired bone repair remains an enormous challenge. Herein, an injectable and photocurable hydrogel therapeutic platform (AMAD/MP) based on alginate methacrylate, alginate-graft-dopamine, and polydopamine (PDA)-functionalized Ti3C2 MXene (MXene@PDA) nanosheets is rationally designed for near-infrared (NIR)-mediated bone regeneration synergistic immunomodulation, osteogenesis, and bacterial elimination. The optimized AMAD/MP hydrogel exhibits favorable biocompatibility, osteogenic activity, and immunomodulatory functions in vitro. The proper immune microenvironment provided by AMAD/MP could further modulate the balance of M1/M2 phenotypes of macrophages, thereby suppressing reactive oxygen species-induced inflammatory status. Significantly, this multifunctional hydrogel platform with mild thermal stimulation efficiently attenuates local immune reactions and further promotes new bone formation without the addition of exogenous cells, cytokines, or growth factors. This work highlights the potential application of an advanced multifunctional hydrogel providing photoactivated on-demand thermal cues for bone tissue engineering and regenerative medicine.

Melt Polycondensation Strategy for Amide-Functionalized l-Aspartic Acid Amphiphilic Polyester Nano-assemblies and Enzyme-Responsive Drug Delivery in Cancer Cells

Aliphatic polyesters are intrinsically enzymatic-biodegradable, and there is ever-increasing demand for safe and smart next-generation biomaterials including drug delivery nano-vectors in cancer research. Using bioresource-based biodegradable polyesters is one of the elegant strategies to meet this requirement; here, we report an l-amino acid-based amide-functionalized polyester platform and explore their lysosomal enzymatic biodegradation aspects to administrate anticancer drugs in cancer cells. l-Aspartic acid was chosen and different amide-side chain-functionalized di-ester monomers were tailor-made having aromatic, aliphatic, and bio-source pendant units. Under solvent-free melt polycondensation methodology; these monomers underwent polymerization to yield high molecular weight polyesters with tunable thermal properties. PEGylated l-aspartic monomer was designed to make thermo-responsive amphiphilic polyesters. This amphiphilic polyester was self-assembled into a 140 ± 10 nm-sized spherical nanoparticle in aqueous medium, which exhibited lower critical solution temperature at 40-42 °C. The polyester nano-assemblies showed excellent encapsulation capabilities for anticancer drug doxorubicin (DOX), anti-inflammatory drug curcumin, biomarkers such as rose bengal (RB), and 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt. The amphiphilic polyester NP was found to be very stable under extracellular conditions and underwent degradation upon exposure to horse liver esterase enzyme in phosphate-buffered saline at 37 °C to release 90% of the loaded cargoes. Cytotoxicity studies in breast cancer MCF 7 and wild-type mouse embryonic fibroblasts cell lines revealed that the amphiphilic polyester was non-toxic to cell lines up to 100 μg/mL, while their drug-loaded polyester nanoparticles were able to inhibit the cancerous cell growth. Temperature-dependent cellular uptake studies further confirmed the energy-dependent endocytosis of polymer NPs across the cellular membranes. Confocal laser scanning microscopy assisted time-dependent cellular uptake analysis directly evident for the endocytosis of DOX loaded polymer NP and their internalization for biodegradation. In a nutshell, the present investigation opens up an avenue for the l-amino acid-based biodegradable polyesters from l-aspartic acids, and the proof of concept is demonstrated for drug delivery in the cancer cell line.

Bone tissue engineering for treating osteonecrosis of the femoral head

Osteonecrosis of the femoral head (ONFH) is a devastating and complicated disease with an unclear etiology. Femoral head-preserving surgeries have been devoted to delaying and hindering the collapse of the femoral head since their introduction in the last century. However, the isolated femoral head-preserving surgeries cannot prevent the natural progression of ONFH, and the combination of autogenous or allogeneic bone grafting often leads to many undesired complications. To tackle this dilemma, bone tissue engineering has been widely developed to compensate for the deficiencies of these surgeries. During the last decades, great progress has been made in ingenious bone tissue engineering for ONFH treatment. Herein, we comprehensively summarize the state-of-the-art progress made in bone tissue engineering for ONFH treatment. The definition, classification, etiology, diagnosis, and current treatments of ONFH are first described. Then, the recent progress in the development of various bone-repairing biomaterials, including bioceramics, natural polymers, synthetic polymers, and metals, for treating ONFH is presented. Thereafter, regenerative therapies for ONFH treatment are also discussed. Finally, we give some personal insights on the current challenges of these therapeutic strategies in the clinic and the future development of bone tissue engineering for ONFH treatment.

Engineered cell-overexpression of circular RNA hybrid hydrogels promotes healing of calvarial defects

Craniomaxillofacial bone defects seriously affect the physical and mental health of patients. Bone marrow mesenchymal stem cells (BMSCs) are "gold standard" cells used for bone repair. However, the collection of BMSCs is invasive, and the osteogenic capacity is limited with age. Human umbilical cord mesenchymal stem cells (hUCMSCs) are promising alternative seed cells for bone tissue engineering. Our group previously used high-throughput sequencing technology and bioinformatics methods to detect circ-CTTN (hsa-circ_0003376) molecules, which may play an essential role in the osteogenic differentiation of hUCMSCs. In this study, osteogenic induction in vitro showed that the overexpressing circ-CTTN (OE group) exhibits a more pronounced osteogenic phenotype. The levels of osteogenesis-related genes in the OE group were highly expressed. The gelatin-methacrylate (GelMA) hydrogel possessed excellent biocompatibility and was used to load hUCMSCs. In the rat calvarial defect, the OE group presented a larger bone healing volume and denser bone trabecular distribution than other groups. So far, the overexpression of circ-CTTN could enhance the osteogenic differentiation of hUCMSCs and accelerate bone reconstruction. Our research could provide a new strategy and a strong theoretical basis for promoting hUCMSC clinical application in bone tissue engineering.

Bench-to-bedside: Feasibility of nano-engineered and drug-delivery biomaterials for bone-anchored implants and periodontal applications

Nanotechnology and drug-release biomaterials have been thoroughly explored in the last few years aiming to develop specialized clinical treatments. However, it is rare to find biomaterials associated with drug delivery properties in the current dental market for application in oral bone- and periodontal-related procedures. The gap between basic scientific evidence and translation to a commercial product remains wide. Several challenges have been reported regarding the clinical translation of biomaterials with drug-delivery systems (BDDS) and nanofeatures. Therefore, processes for BDDS development, application in preclinical models, drug delivery doses, sterilization processes, storage protocols and approval requirements were explored in this review, associated with tentative solutions for these issues. The diversity of techniques and compounds/molecules applied to develop BDDS demands a case-by-case approach to manufacturing and validating a commercial biomaterial. Promising outcomes such as accelerated tissue healing and higher antibacterial response have been shown through basic and preclinical studies using BDDS and nano-engineered biomaterials; however, the adequate process for sterilization, storage, cost-effectiveness and possible cytotoxic effects remains unclear for multifunctional biomaterials incorporated with different chemical compounds; then BDDSs are rarely translated into products. The future benefits of BDDS and nano-engineered biomaterials have been reported suggesting personalized clinical treatment and a promising reduction in the use of systemic antibiotics. Finally, the launch of these specialized biomaterials with solid data and controlled traceability onto the market will generate strong specificity for healthcare treatments.

Polycaprolactone-based scaffolds for guided tissue regeneration in periodontal therapy: A systematic review

BACKGROUND

Polycaprolactone (PCL) is a highly recognized synthetic polymer for its biocompatibility, ease of fabrication and mechanical strength in bone tissue engineering. Its applications have extended broadly, including regeneration of oral and maxillofacial lost tissues. Its usefulness has brought attention of researchers to regenerate periodontal lost tissues, including alveolar bone, periodontal ligament and cementum. The aim of this systematic review was to obtain an updated analysis of the contribution of PCL-based scaffolds in the alveolar bone regeneration process.

METHODS

This review adheres to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for systematic reviews. A computerized search of the PubMed, EBSCO, Scielo and Web of Science databases was performed, restricting literature search to published studies in English or Spanish between January 2002 and March 2023. Database search returned 248 studies which were screened based on title, author names and publication dates.

RESULTS

Data from 17 studies were reviewed and tabulated. All studies combined PCL with other biomaterials (such as Alginate, hydroxyapatite, bioactive glass, poly (lactic-co-glycolic acid)), growth factors (BMP-2, rhCEMP1), and/or mesenchymal stromal cells (adipose-derived, bone marrow, periodontal ligament or gingiva mesenchymal stromal cells). PCL scaffolds showed higher cell viability and osteoinductive potential when combined with bioactive agents. Complementary, its degradation rates were affected by the addition or exposure to specific substances, such as: Dopamine, Cerium Oxide, PLGA and hydrogen peroxide.

CONCLUSIONS

PCL is an effective biomaterial for alveolar bone regeneration in periodontally affected teeth. It could be part of a new generation of biomaterials with improved regenerative potential.

Stimuli-Activable Metal-Bearing Nanomaterials and Precise On-Demand Antibacterial Strategies

Bacterial infections remain the leading cause of death worldwide today. The emergence of antibiotic resistance has urged the development of alternative antibacterial technologies to complement or replace traditional antibiotic treatments. In this regard, metal nanomaterials have attracted great attention for their controllable antibacterial functions that are less prone to resistance. This review discusses a particular family of stimuli-activable metal-bearing nanomaterials (denoted as SAMNs) and the associated on-demand antibacterial strategies. The various SAMN-enabled antibacterial strategies stem from basic light and magnet activation, with the addition of bacterial microenvironment responsiveness and/or bacteria-targeting selectivity and therefore offer higher spatiotemporal controllability. The discussion focuses on nanomaterial design principles, antibacterial mechanisms, and antibacterial performance, as well as emerging applications that desire on-demand and selective activation (i.e., medical antibacterial treatments, surface anti-biofilm, water disinfection, and wearable antibacterial materials). The review concludes with the authors' perspectives on the challenges and future directions for developing industrial translatable next-generation antibacterial strategies.

The role of the immune microenvironment in bone, cartilage, and soft tissue regeneration: from mechanism to therapeutic opportunity

Bone, cartilage, and soft tissue regeneration is a complex spatiotemporal process recruiting a variety of cell types, whose activity and interplay must be precisely mediated for effective healing post-injury. Although extensive strides have been made in the understanding of the immune microenvironment processes governing bone, cartilage, and soft tissue regeneration, effective clinical translation of these mechanisms remains a challenge. Regulation of the immune microenvironment is increasingly becoming a favorable target for bone, cartilage, and soft tissue regeneration; therefore, an in-depth understanding of the communication between immune cells and functional tissue cells would be valuable. Herein, we review the regulatory role of the immune microenvironment in the promotion and maintenance of stem cell states in the context of bone, cartilage, and soft tissue repair and regeneration. We discuss the roles of various immune cell subsets in bone, cartilage, and soft tissue repair and regeneration processes and introduce novel strategies, for example, biomaterial-targeting of immune cell activity, aimed at regulating healing. Understanding the mechanisms of the crosstalk between the immune microenvironment and regeneration pathways may shed light on new therapeutic opportunities for enhancing bone, cartilage, and soft tissue regeneration through regulation of the immune microenvironment.

Bioinspired sandwich-like hybrid surface functionalized scaffold capable of regulating osteogenesis, angiogenesis, and osteoclastogenesis for robust bone regeneration

Recently, strategies that focus on biofunctionalized implant surfaces to enhance bone defect healing through the synergistic regulation of osteogenesis, angiogenesis, and osteoclastogenesis have attracted increasing attention in the bone tissue engineering field. Studies have shown that the Wnt/β-catenin signaling pathway has an imperative effect of promoting osteogenesis and angiogenesis while reducing osteoclastogenesis. However, how to prepare biofunctionalized bone implants with balanced osteogenesis, angiogenesis, and osteoclastogenesis by activating the Wnt/β-catenin pathway has seldom been investigated. Herein, through a bioinspired dopamine chemistry and self-assembly method, BML-284 (BML), a potent and highly selective Wnt signaling activator, was loaded on a mussel-inspired polydopamine (PDA) layer that had been immobilized on the porous beta-tricalcium calcium phosphate (β-TCP) scaffold surface and subsequently modified by a biocompatible carboxymethyl chitosan hydrogel to form a sandwich-like hybrid surface. β-TCP provides a biomimetic three-dimensional porous microenvironment similar to that of natural cancellous bone, and the BML-loaded sandwich-like hybrid surface endows the scaffold with multifunctional properties for potential application in bone regeneration. The results show that the sustained release of BML from the sandwich-like hybrid surface significantly facilitates the adhesion, migration, proliferation, spreading, and osteogenic differentiation of MC3T3-E1 cells as well as the angiogenic activity of human umbilical vein endothelial cells. In addition to osteogenesis and angiogenesis, the hybrid surface also exerts critical roles in suppressing osteoclastic activity. Remarkably, in a critical-sized cranial defect model, the biofunctionalized β-TCP scaffold could potentially trigger a chain of biological events: stimulating the polarization of M2 macrophages, recruiting endogenous stem cells and endothelial cells at the injury site to enable a favorable microenvironment for greatly accelerating bone ingrowth and angiogenesis while compromising osteoclastogenesis, thereby promoting bone healing. Therefore, these surface-biofunctionalized β-TCP implants, which regulate the synergies of osteogenesis, angiogenesis, and anti-osteoclastogenesis, indicate strong potential for clinical application as advanced orthopedic implants.

The esterified lentinan bilayer nanofibrous membrane for promoting wound healing

Host reactions following implantation of biomaterials, especially the macrophages' responses could significantly affect the wound healing process. Therefore, it is meaningful to develop immunostimulatory active wound dressing to accelerate wound healing. In this study, lentinan (LNT) was esterified with different carboxylic acids, and the bilayer nanofibrous membrane (BilayerM) based on the esterified LNT was designed. BilayerM exhibited good water absorption, red blood cells (RBC), platelets, and fibronectin adhesion abilities. The ELISA results indicated that BilayerM stimulated macrophages to secrete pro-inflammatory and pro-regenerative cytokines. Moreover, cell migration results showed that BilayerM promoted the migration and proliferation of NIH3T3 and HUVECs. The wound healing efficacy studies demonstrated that BilayerM significantly accelerated the wound healing rate in a full-thickness skin defect model. Therefore, these results indicate that this bioactive dressing is a hopeful candidate for clinical treatment of cutaneous wounds.

Membranes for the life sciences and their future roles in medicine

Since the global outbreak of COVID-19, membrane technology for clinical treatments, including extracorporeal membrane oxygenation (ECMO) and protective masks and clothing, has attracted intense research attention for its irreplaceable abilities. Membrane research and applications are now playing an increasingly important role in various fields of life science. In addition to intrinsic properties such as size sieving, dissolution and diffusion, membranes are often endowed with additional functions as cell scaffolds, catalysts or sensors to satisfy the specific requirements of different clinical applications. In this review, we will introduce and discuss state-of-the-art membranes and their respective functions in four typical areas of life science: artificial organs, tissue engineering, in vitro blood diagnosis and medical support. Emphasis will be given to the description of certain specific functions required of membranes in each field to provide guidance for the selection and fabrication of the membrane material. The advantages and disadvantages of these membranes have been compared to indicate further development directions for different clinical applications. Finally, we propose challenges and outlooks for future development.

Adhesive Gelatin-Catechol Complex Reinforced Poly(Acrylic Acid) Hydrogel with Enhanced Toughness and Cell Affinity for Cartilage Regeneration

The repair of cartilage damage caused by trauma, wear, or degenerative deformation remains a major challenge in modern medicine. Therefore, it is essential to develop a mechanically compatible and bioactive scaffold for cartilage tissue regeneration. In this study, a mussel-inspired, tough, adhesive polydopamine/gelatin-poly(acrylic acid) (PDA/Gel-PAA) composite hydrogel was developed for cartilage regeneration. The hydrogel achieved a high compressive strength of up to 0.67 MPa and a toughness of 420 J/m2 because of the unique chemical-physical cross-linking structure by introducing the PDA/Gel complex into the PAA network. PAA chains with rich carboxyl groups mimic the negatively charged glycosaminoglycans (GAGs) in the natural cartilage extracellular matrix (ECM), leading to strong water retention in the hydrogel. The incorporation of the PDA/Gel complex with catechol groups on PDA and arginine-glycine-aspartic acid (RGD) sequences on gelatin chains provided abundant adhesive motifs to improve the cell affinity and tissue adhesiveness of PAA, thereby facilitating the adhesion and proliferation of bone marrow stromal cells (BMSCs). In addition, transforming growth factor-β3 (TGFβ3) was stably immobilized and released from the PDA/Gel-PAA hydrogel. Thus, adhesive hydrogels can provide a suitable microenvironment to promote cell migration in the defect area and induce chronogenesis for cartilage regeneration.

Nanoparticles incorporated in nanofibers using electrospinning: A novel nano-in-nano delivery system

Nanofibers are cutting-edge drug delivery systems that are being utilised to treat a variety of ailments. Nanofibers are mostly woven by electrospinning techniques that are majorly used in drug delivery, wound dressing, tissue engineering, sensors, etc. They have several limitations that can be addressed by developing nano-in-nano delivery techniques. Nanoparticles are incorporated into nanofibers in these nano-in-nano systems. They offer a lot of benefits over other nanosystems, including the ability to shield drugs from physical deterioration, the ability to provide prolonged drug release, high surface area to volume ratio, increased drug loading capacity and the potential to be employed in critical conditions such as cancer. These nanoparticles can be encapsulated, entrapped, or adsorbed onto nanofibers in a variety of ways. To include nanosystems into nanofibers, a variety of materials and different kinds of nanoparticles can be used. The present review gives an insight to the applications of nano - in - nano drug delivery system for different diseases/disorders. The review also brings forward the current state of these novel delivery systems along with future perspectives.

Polycaprolactone scaffolds as a biomaterial for cementoblast delivery: An in vitro study

OBJECTIVE

To define the potential of polycaprolactone (PCL) scaffold for cementoblast delivery.

BACKGROUND

Dental cementum is critical for tooth attachment and position, and its regenerative capabilities remain unpredictable.

METHODS

PCL scaffolds were manufactured by the electrospinning technique at 10% and 20% (w/v) and seeded with cementoblasts (OCCM-30). Scaffolds were characterized for their morphology and biological performance by scanning electron microscopy (SEM), confocal and conventional histology, cytocompatibility (PrestoBlue assay), gene expression (type I collagen - Col1; bone sialoprotein - Bsp; runt-related transcription factor 2 - Runx-2; alkaline phosphatase - Alpl; osteopontin - Opn; osteocalcin - Ocn, osterix - Osx), and the potential to induce extracellular matrix deposition and mineralization in vitro.

RESULTS

Overall, data analysis showed that PCL scaffolds allowed cell adhesion and proliferation, modulated the expression of key markers of cementoblasts, and led to enhanced extracellular matrix deposition and calcium deposition as compared to the control group.

CONCLUSION

Altogether, our findings allow concluding that PCL scaffolds are a viable tool to culture OCCM-30 cells, leading to an increased potential to promote mineralization in vitro. Further studies should be designed in order to define the clinical relevance of cementoblast-loaded PCL scaffolds to promote new cementum formation.

Various Coated Barrier Membranes for Better Guided Bone Regeneration: A Review

A good barrier membrane is one of the important factors for effective guided bone/tissue regeneration (GBR/GTR) in the case of periodontal bone defects. Several methods are being discussed to overcome and improve the shortcomings of commercially available membranes. One of the methods is to coat the membrane with bioactive materials. In this study, 41 studies related to coated membranes for GBR/GTR published in the last 5 years were reviewed. These studies reported coating the membrane with various bioactive materials through different techniques to improve osteogenesis, antimicrobial properties, and physical/mechanical properties. The reported studies have been classified and discussed based on the purpose of coating. The goal of the most actively studied research on coating or surface modification of membranes is to improve new bone formation. For this purpose, calcium phosphate, bioactive glass, polydopamine, osteoinduced drugs, chitosan, platelet-rich fibrin, enamel matrix derivatives, amelotin, hyaluronic acid, tantalum, and copper were used as membrane coating materials. The paradigm of barrier membranes is changing from only inert (or biocompatible) physical barriers to bioactive osteo-immunomodulatory for effective guided bone and tissue regeneration. However, there is a limitation that there exists only a few clinical studies on humans to date. Efforts are needed to implement the use of coated membranes from the laboratory bench to the dental chair unit. Further clinical studies are needed in the patients’ group for long-term follow-up to confirm the effect of various coating materials.

Mussel-Inspired Polydopamine-Based Multilayered Coatings for Enhanced Bone Formation

Repairing bone defects remains a challenge in clinical practice and the application of artificial scaffolds can enhance local bone formation, but the function of unmodified scaffolds is limited. Considering different application scenarios, the scaffolds should be multifunctionalized to meet specific demands. Inspired by the superior adhesive property of mussels, polydopamine (PDA) has attracted extensive attention due to its universal capacity to assemble on all biomaterials and promote further adsorption of multiple external components to form PDA-based multilayered coatings with multifunctional property, which can induce synergistic enhancement of new bone formation, such as immunomodulation, angiogenesis, antibiosis and antitumor property. This review will summarize mussel-inspired PDA-based multilayered coatings for enhanced bone formation, including formation mechanism and biofunction of PDA coating, as well as different functional components. The synergistic enhancement of multiple functions for better bone formation will also be discussed. This review will inspire the design and fabrication of PDA-based multilayered coatings for different application scenarios and promote deeper understanding of their effect on bone formation, but more efforts should be made to achieve clinical translation. On this basis, we present a critical conclusion, and forecast the prospects of PDA-based multilayered coatings for bone regeneration.

Metal Ion Augmented Mussel Inspired Polydopamine Immobilized 3D Printed Osteoconductive Scaffolds for Accelerated Bone Tissue Regeneration

Critical bone defects with a sluggish rate of auto-osteoconduction and imperfect reconstruction are motivators for the development of an alternate innovative approach for the regeneration of bone. Tissue engineering for bone regeneration signifies an advanced way to overcome this problem by creating an additional bone tissue substitute. Among different fabrication techniques, the 3D printing technique is obviously the most efficient and advanced way to fabricate an osteoconductive scaffold with a controlled porous structure. In the current article, the polycarbonate and polyester diol based polyurethane-urea (P12) was synthesized and 3D porous nanohybrid scaffolds (P12/TP-nHA) were fabricated using the 3D printing technique by incorporating the osteoconductive nanomaterial titanium phosphate adorned nanohydroxyapatite (TP-nHA). To improve the bioactivity, the surface of the fabricated scaffolds was modified with the immobilized biomolecule polydopamine (PDA) at room temperature. XPS study as well as the measurement of surface wettability confirmed the higher amount of PDA immobilization on TP-nHA incorporated nanohybrid scaffolds through the dative bone formation between the vacant d orbital of the incorporated titanium ion and the lone pair electron of the catechol group of dopamine. The incorporated titanium phosphate (TP) increased the tensile strength (53.1%) and elongation at break (96.8%) of the nanohybrid composite as compared to pristine P12. Moreover, the TP incorporated nanohybrid scaffold with calcium and phosphate moieties and a higher amount of immobilized active biomolecule improved the in vitro bioactivity, including the cell viability, cell proliferation, and osteogenic gene expression using hMSCs, of the fabricated nanohybrid scaffolds. A rat tibia defect model depicted that the TP incorporated nanohybrid scaffold with immobilized PDA enhanced the in vivo bone regeneration ability compared to the control sample without revealing any organ toxicity signifying the superior osteogenic bioactivity. Thus, a TP augmented polydopamine immobilized polyurethane-urea based nanohybrid 3D printed scaffold with improved physicochemical properties and osteogenic bioactivity could be utilized as an excellent advanced material for bone regeneration substitute.

Reinforced Blood-Derived Protein Hydrogels Enable Dual-Level Regulation of Bio-Physiochemical Microenvironments for Personalized Bone Regeneration with Remarkable Enhanced Efficacy

Physiological microenvironment engineering has shown great promise in combating a variety of diseases. Herein, we present the rational design of reinforced and injectable blood-derived protein hydrogels (PDA@SiO₂-PRF) composed of platelet-rich fibrin (PRF), polydopamine (PDA), and SiO₂ nanofibers that can act as dual-level regulators to engineer the microenvironment for personalized bone regeneration with high efficacy. From the biophysical level, PDA@SiO₂-PRF with high stiffness can withstand the external loading and maintaining the space for bone regeneration in bone defects. Particularly, the reinforced structure of PDA@SiO₂-PRF provides bone extracellular matrix (ECM)-like functions to stimulate osteoblast differentiation via Yes-associated protein (YAP) signaling pathway. From the biochemical level, the PDA component in PDA@SiO₂-PRF hinders the fast degradation of PRF to release autologous growth factors in a sustained manner, providing sustained osteogenesis capacity. Overall, the present study offers a dual-level strategy for personalized bone regeneration by engineering the biophysiochemical microenvironment to realize enhanced osteogenesis efficacy.

Mussel-inspired multifunctional surface through promoting osteogenesis and inhibiting osteoclastogenesis to facilitate bone regeneration

Osteogenesis and osteoclastogenesis are closely associated during the bone regeneration process. The development of multifunctional bone repair scaffolds with dual therapeutic actions (pro-osteogenesis and anti-osteoclastogenesis) is still a challenging task for bone tissue engineering applications. Herein, through a facile surface coating process, mussel-inspired polydopamine (PDA) is adhered to the surface of a biocompatible porous scaffold followed by the immobilization of a small-molecule activator (LYN-1604 (LYN)) and the subsequent in situ coprecipitation of hydroxyapatite (HA) nanocrystals. PDA, acting as an intermediate bridge, can provide strong LYN immobilization and biomineralization ability, while LYN targets osteoclast precursor cells to inhibit osteoclastic differentiation and functional activity, which endows LYN/HA-coated hybrid scaffolds with robust anti-osteoclastogenesis ability. Due to the synergistic effects of the LYN and HA components, the obtained three-dimensional hybrid scaffolds exhibited the dual effects of osteoclastic inhibition and osteogenic stimulation, thereby promoting bone tissue repair. Systematic characterization experiments confirmed the successful fabrication of LYN/HA-coated hybrid scaffolds, which exhibited an interconnected porous structure with nanoroughened surface topography, favorable hydrophilicity, and improved mechanical properties, as well as the sustained sequential release of LYN and Ca ions. In vitro experiments demonstrated that LYN/HA-coated hybrid scaffolds possessed satisfactory cytocompatibility, effectively promoting cell adhesion, spreading, proliferation, alkaline phosphatase activity, matrix mineralization, and osteogenesis-related gene and protein secretion, as well as stimulating angiogenic differentiation of endothelial cells. In addition to osteogenesis, the engineered scaffolds also significantly reduced osteoclastogenesis, such as tartrate-resistant acid phosphatase activity, F-actin ring staining, and osteoclastogenesis-related gene and protein secretion. More importantly, in a rat calvarial defect model, the newly developed hybrid scaffolds significantly promoted bone repair and regeneration. Microcomputed tomography, histological, and immunohistochemical analyses all revealed that the LYN/HA-coated hybrid scaffolds possessed not only reliable biosafety but also excellent osteogenesis-inducing and osteoclastogenesis-inhibiting effects, resulting in faster and higher-quality bone tissue regeneration. Taken together, this study offers a powerful and promising strategy to construct multifunctional nanocomposite scaffolds by promoting osteo/angiogenesis and suppressing osteoclastogenesis to accelerate bone regeneration.

Two-Dimensional Nanomaterials beyond Graphene for Biomedical Applications

Two-dimensional (2D) nanomaterials (e.g., graphene) have shown to have a high potential in future biomedical applications due to their unique physicochemical properties such as unusual electrical conductivity, high biocompatibility, large surface area, and extraordinary thermal and mechanical properties. Although the potential of graphene as the most common 2D nanomaterials in biomedical applications has been extensively investigated, the practical use of other nanoengineered 2D materials beyond graphene such as transition metal dichalcogenides (TMDs), topological insulators (TIs), phosphorene, antimonene, bismuthene, metal-organic frameworks (MOFs) and MXenes for biomedical applications have not been appreciated so far. This review highlights not only the unique opportunities of 2D nanomaterials beyond graphene in various biomedical research areas such as bioelectronics, imaging, drug delivery, tissue engineering, and regenerative medicine but also addresses the risk factors and challenges ahead from the medical perspective and clinical translation of nanoengineered 2D materials. In conclusion, the perspectives and future roadmap of nanoengineered 2D materials beyond graphene are outlined for biomedical applications.