Application of metal-organic framework materials in regenerative medicine

In the past few decades, scaffolds manufactured from composite or hybrid biomaterials of natural or synthetic origin have made great strides in enhancing wound healing and repairing fractures and pathological bone loss. However, the prevailing use of such scaffolds in tissue engineering is accompanied by numerous constraints, including low mechanical stability, poor biological activity, and impaired cell proliferation and differentiation. The performance of scaffolds in wound and bone tissue engineering may be enhanced by some modifications in the synthesis of nanoscale metal-organic framework (nano-MOF) scaffolds. Nano-MOFs have attracted researchers' attention in recent years due to their distinctive features, which include tenability, biocompatibility, good mechanical stability, and ultrahigh surface area. The biological properties of scaffolds are enhanced and tissue regeneration is facilitated by the introduction of nano-MOFs. Moreover, the physicochemical characteristics, drug loading, and ion release capacities of the scaffolds are improved by the nanoscale structure and topological features of nano-MOFs, which also control stem cell differentiation, proliferation, and attachment. This review provides further comprehensive detail about the most recent uses of nano-MOFs in tissue engineering. The distinct characteristics of nano-MOFs are explored in enhancing tissue repair, wound healing, osteoinduction, and bone conductivity. Significant attributes include high antibacterial activity, substantial drug-loading capacity, and the ability to regulate drug release. Finally, this discussion addresses the obstacles, clinical impediments, and considerations encountered in the application of these nanomaterials to diverse scaffolds, tissue-mimicking structures, dressings, fillers, and implants for bone tissue repair and wound healing.

Study on chitosan/gelatin hydrogels containing ceria nanoparticles for promoting the healing of diabetic wound

Chronic inflammation at diabetic wound sites results in the uncontrolled accumulation of pro-inflammatory factors and reactive oxygen species (ROS), which impedes cell proliferation and delays wound healing. To promote the healing of diabetic wounds, chitosan/gelatin hydrogels containing ceria nanoparticles (CNPs) of various sizes were created in the current study. CNPs' efficacy in removingO 2 • - , •OH, and H2O2 was demonstrated, and the scavenging ability of CNPs of varying sizes was compared. The in vitro experiments demonstrated that hydrogels containing CNPs could effectively protect cells from ROS-induced damage and facilitate mouse fibroblast migration. Furthermore, during the treatment of diabetic wounds in vivo, hydrogels containing CNPs exhibited anti-inflammatory activity and could reduce the expression of the pro-inflammatory factors TNF-α (above 30%), IL-6 (above 90%), and IL-1β (above 80%), and effectively promote wound closure (above 80%) by inducing re-epithelialization, collagen deposition, and angiogenesis. In addition, the biological properties and therapeutic effects of hydrogels containing CNPs of various sizes were compared and discussed. The finding revealed that hydrogels with 4 nm CNPs exhibited more significant biological properties and had implications for diabetic wound treatment.

Nanomaterial strategies in wound healing: A comprehensive review of nanoparticles, nanofibres and nanosheets

Wound healing is a complex process that orchestrates the coordinated action of various cells, cytokines and growth factors. Nanotechnology offers exciting new possibilities for enhancing the healing process by providing novel materials and approaches to deliver bioactive molecules to the wound site. This article elucidates recent advancements in utilizing nanoparticles, nanofibres and nanosheets for wound healing. It comprehensively discusses the advantages and limitations of each of these materials, as well as their potential applications in various types of wounds. Each of these materials, despite sharing common properties, can exhibit distinct practical characteristics that render them particularly valuable for healing various types of wounds. In this review, our primary focus is to provide a comprehensive overview of the current state-of-the-art in applying nanoparticles, nanofibres, nanosheets and their combinations to wound healing, serving as a valuable resource to guide researchers in their appropriate utilization of these nanomaterials in wound-healing research. Further studies are necessary to gain insight into the application of this type of nanomaterials in clinical settings.

Recent advances in reactive oxygen species scavenging nanomaterials for wound healing

Reactive oxygen species play a crucial role in cell signaling pathways during wound healing phases. Treatment strategies to balance the redox level in the deep wound tissue are emerging for wound management. In recent years, reactive oxygen species scavenging agents including natural antioxidants, reactive oxygen species (ROS) scavenging nanozymes, and antioxidant delivery systems have been widely employed to inhibit oxidative stress and promote skin regeneration. Here, the importance of reactive oxygen species in different wound healing phases is critically analyzed. Various cutting-edge bioactive ROS nanoscavengers and antioxidant delivery platforms are discussed. This review also highlights the future directions for wound therapies via reactive oxygen species scavenging. This comprehensive review offers a map of the research on ROS scavengers with redox balancing mechanisms of action in the wound healing process, which benefits development and clinical applications of next-generation ROS scavenging-based nanomaterials in skin regeneration.

Ipomoea pes-tigridis L. extract accelerates wound healing in Wistar albino rats in excision and incision models

ETHNOPHARMACOLOGICAL RELEVANCE

An annual herb, Ipomoea pes-tigridis L. (Convolvulaceae) is widely used for its anti-inflammatory and anti-spasmodic properties in traditional medicine. As well as treating wounds, fever, skin disorders, and other ailments, it is also used for other purposes.

AIM OF THE STUDY

This study investigated polyphenolic content, antioxidant activity, RP-HPLC, wound healing, and antioxidant enzyme activity. In terms of I. pes-tigridis potential for healing wounds, there is no scientific data available. Hence this study is designed to use animal models to investigate the ethnopharmacological report.

MATERIALS METHODS

The crude extracts of stem and leaf were subjected to phytochemicals, TPC, TTC, TFC, and free radical scavenging assays (DPPH, ABTS, etc). Excision and incision models were used to assess wound healing using the screened extracts (IPLEA, IPLM, IPSEA, and IPSM). Various tissue parameters (hydroxyproline, hexosamine, hexuronic acid content), as well as antioxidant enzyme activity (SOD, Catalase, GPX, LPO), were also examined.

RESULTS

The maximum amount of polyphenolic content was found in IPLM (TPC- 118.86 ± 5.94 mg GAE/g, TTC - 75.25 ± 2.64 mg TAE/g, and TFC-25.73 ± 0.99 mg GAE/g) with significant IC50 value of 1.65 ± 0.87 μg/mL among all the extracts. Coumaric acid was reported high (92.86 mg/g) in RP-HPLC analysis of crude extract in IPLEA. The in vivo excision wound healing model revealed that 1% IPLM had better healing property with the maximum wound healing area (0.098 ± 0.03 cm) and wound concentration (95.56 ± 1.95%) was reported with the significance level of ***P < 0.001, **P < 0.01, *P < 0.05. In the incision model, IPLM represented maximum tensile strength (27500 gf). A significant functional effect of the granulation tissue parameters and enzyme antioxidants on the wound-healed area of dry tissue was also observed. Finally, the histopathological analysis showed enhanced re-epithelialization, fibroblast proliferation, and collagen synthesis in wound-treated animal tissue in both models.

CONCLUSION

According to the present study, antioxidant-rich I. pes-tigridis promotes healthy cell regeneration while reducing inflammation and oxidative stress for wound healing. Additionally, it also enhances circulation and promotes healing.

Reactive oxygen species (ROS) scavenging biomaterials for anti-inflammatory diseases: from mechanism to therapy

Inflammation is a fundamental defensive response to harmful stimuli, but the overactivation of inflammatory responses is associated with most human diseases. Reactive oxygen species (ROS) are a class of chemicals that are generated after the incomplete reduction of molecular oxygen. At moderate levels, ROS function as critical signaling molecules in the modulation of various physiological functions, including inflammatory responses. However, at excessive levels, ROS exert toxic effects and directly oxidize biological macromolecules, such as proteins, nucleic acids and lipids, further exacerbating the development of inflammatory responses and causing various inflammatory diseases. Therefore, designing and manufacturing biomaterials that scavenge ROS has emerged an important approach for restoring ROS homeostasis, limiting inflammatory responses and protecting the host against damage. This review systematically outlines the dynamic balance of ROS production and clearance under physiological conditions. We focus on the mechanisms by which ROS regulate cell signaling proteins and how these cell signaling proteins further affect inflammation. Furthermore, we discuss the use of potential and currently available-biomaterials that scavenge ROS, including agents that were engineered to reduce ROS levels by blocking ROS generation, directly chemically reacting with ROS, or catalytically accelerating ROS clearance, in the treatment of inflammatory diseases. Finally, we evaluate the challenges and prospects for the controlled production and material design of ROS scavenging biomaterials.

In vitro and in vivo evaluation of alginate hydrogel-based wound dressing loaded with green chemistry cerium oxide nanoparticles

Interactive wound dressings have displayed promising outcomes in enhancing the wound healing process. This study focuses on creating a nanocomposite wound dressing with interactive and bioactive properties, showcasing potent antioxidant effects. To achieve this, we developed cerium oxide nanoparticles utilizing curcumin as both the reducing and capping agent. Characterization techniques such as SEM, EDX, DLS, Zetasizer, FTIR, and XRD were utilized to analyze the cerium oxide nanoparticles synthesized through a green approach. The image analysis on the obtained TEM images showed that the curcumin-assisted biosynthesized CeO2NPs have a size of 18.8 ± 4.1 nm. The peaks located at 28.1, 32.7, 47.1, 56.0, 58.7, 69.0, and 76.4 correspond to (111), (200), (220), (311), (222), (400), and (331) crystallographic planes. We applied the Debye-Scherrer equation and observed that the approximate crystallite size of the biosynthesized NPs is around 8.2 nm based on the most intensive broad Bragg peak at 28.1°. The cerium oxide nanoparticles synthesized were integrated into an alginate hydrogel matrix, and the microstructure, porosity, and swelling behavior of the resulting wound dressing were assessed. The characterization analyses provided insights into the physical and chemical properties of the green-synthesized cerium oxide nanoparticles and the alginate hydrogel-based wound dressing. In vitro studies demonstrated that the wound dressing based on alginate hydrogel exhibited favorable antioxidant properties and displayed hemocompatibility and biocompatibility. Animal studies conducted on a rat full-thickness skin wound model showed that the alginate hydrogel-based wound dressing effectively accelerated the wound healing process. Overall, these findings suggest that the alginate hydrogel-based wound dressing holds promise as a highly effective material for wound healing applications.

Recent Advances on Cerium Oxide-Based Biomaterials: Toward the Next Generation of Intelligent Theranostics Platforms

Disease or organ damage due to unhealthy living habits, or accidents, is inevitable. Discovering an efficient strategy to address these problems is urgently needed in the clinic. In recent years, the biological applications of nanotechnology have received extensive attention. Among them, as a widely used rare earth oxide, cerium oxide (CeO2 ) has shown good application prospects in biomedical fields due to its attractive physical and chemical properties. Here, the enzyme-like mechanism of CeO2 is elucidated, and the latest research progress in the biomedical field is reviewed. At the nanoscale, Ce ions in CeO2 can be reversibly converted between +3 and +4. The conversion process is accompanied by the generation and elimination of oxygen vacancies, which give CeO2 the performance of dual redox properties. This property facilitates nano-CeO2 to catalyze the scavenging of excess free radicals in organisms, hence providing a possibility for the treatment of oxidative stress diseases such as diabetic foot, arthritis, degenerative neurological diseases, and cancer. In addition, relying on its excellent catalytic properties, customizable life-signaling factor detectors based on electrochemical techniques are developed. At the end of this review, an outlook on the opportunities and challenges of CeO2 in various fields is provided.

Photothermal effective CeO2NPs combined in thermosensitive hydrogels with enhanced antibacterial, antioxidant and vascularization performance to accelerate infected diabetic wound healing

Chronic diabetic wound healing remains a formidable challenge due to susceptibility to bacterial infection, excessive oxidative stress, and poor angiogenesis. To address these issues, a sodium alginate (SA) based photothermal hydrogel dressing with multifunction was fabricated to facilitate wound treatment. Ceria nanoparticles (CeO2NPs) was synthesized, and their antibacterial performance by near-infrared light triggered photothermal effects was first studied and verified in this work. In addition, to release CeO2NPs to achieve antioxidation and pro-vascularization, thermosensitive gelatin (Gel) was utilized to embed the nanoparticles in advance and then composited in SA hydrogel networks. SA network was finally strengthened by acid soaking to form partially crystalline regions to act as natural crosslinkers. Results showed that the Gel/SA/CeO2 hydrogel displayed temperature-responsive release of CeO2NPs, significant antibacterial and antioxidative activity, as well as the ability to remove without injury and promote infected diabetic wound healing with low cytotoxicity, according to antibacterial investigations, cell studies, and in vivo animal studies. This research offers not only a successful method for quickening the healing of diabetic wounds but also a fresh approach to the general use of CeO2NPs.

Structural and functional insights in polysaccharides coated cerium oxide nanoparticles and their potential biomedical applications: A review

Cerium oxide nanoparticles have now significant presence in biomedical fields due to their wide applications; however, challenges regarding their safety and biocompatibility persist. Polysaccharides based biopolymers have inherent hydroxyl and carboxyl groups, enabling them to govern the surface functionalization of cerium oxide nanoparticles, hence their chemical and physical characteristics. Because of this, polysaccharides such as dextran, alginate, pullulan, chitosan, polylactic acid, starch, and pectin are practical substitutes for the conventional coatings used to synthesize cerium oxide nanoparticles. This review discusses the effect of biopolymer coatings on the properties of cerium oxide nanoparticles, such as size, stability, aggregation, and biocompatibility. Additionally, it also summarises various biomedical applications of polysaccharides coated cerium oxide nanoparticles, such as in bone tissue regeneration, liver inflammation, wound healing, and antibacterial and anticancer activities. Biocompatible cerium oxide nanoparticles will surely improve their applications in the biomedical field.

Anti-oxidant anti-inflammatory and antibacterial tannin-crosslinked citrate-based mussel-inspired bioadhesives facilitate scarless wound healing

The revolutionary role of tissue adhesives in wound closure, tissue sealing, and bleeding control necessitates the development of multifunctional materials capable of effective and scarless healing. In contrast to the use of traditionally utilized toxic oxidative crosslinking initiators (exemplified by sodium periodate and silver nitrate), herein, the natural polyphenolic compound tannic acid (TA) was used to achieve near instantaneous (<25s), hydrogen bond mediated gelation of citrate-based mussel-inspired bioadhesives combining anti-oxidant, anti-inflammatory, and antimicrobial activities (3A-TCMBAs). The resulting materials were self-healing and possessed low swelling ratios (<60%) as well as considerable mechanical strength (up to ∼1.0 MPa), elasticity (elongation ∼2700%), and adhesion (up to 40 kPa). The 3A-TCMBAs showed strong in vitro and in vivo anti-oxidant ability, favorable cytocompatibility and cell migration, as well as photothermal antimicrobial activity against both Staphylococcus aureus and Escherichia coli (>90% bacterial death upon near-infrared (NIR) irradiation). In vivo evaluation in both an infected full-thickness skin wound model and a rat skin incision model demonstrated that 3A-TCMBAs + NIR treatment could promote wound closure and collagen deposition and improve the collagen I/III ratio on wound sites while simultaneously inhibiting the expression of pro-inflammatory cytokines. Further, phased angiogenesis was observed via promotion in the early wound closure phases followed by inhibition and triggering of degradation & remodeling of the extracellular matrix (ECM) in the late stage (supported by phased CD31 (platelet endothelial cell adhesion molecule-1) PDGF (platelet-derived growth factor) and VEGF (vascular endothelial growth factor) expression as well as elevated matrix metalloprotein-9 (MMP-9) expression on day 21), resulting in scarless wound healing. The significant convergence of material and bioactive properties elucidated above warrant further exploration of 3A-TCMBAs as a significant, new class of bioadhesive.

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Citrate-based mussel-inspired bioadhesive prepolymers were crosslinked with tannic acid via hydrogen bonding (3A-TCMBAs).

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3A-TCMBAs showed good tissue adhesiveness, self-healing and elastic properties.

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3A-TCMBAs exhibited photothermal antibacterial, antioxidant and anti-inflammatory efficiency.

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3A-TCMBAs could promote scarless wound healing by enabling phased angiogenesis.

Microenvironment-Based Diabetic Foot Ulcer Nanomedicine

Diabetic foot ulcers (DFU), one of the most serious complications of diabetes, are essentially chronic, nonhealing wounds caused by diabetic neuropathy, vascular disease, and bacterial infection. Given its pathogenesis, the DFU microenvironment is rather complicated and characterized by hyperglycemia, ischemia, hypoxia, hyperinflammation, and persistent infection. However, the current clinical therapies for DFU are dissatisfactory, which drives researchers to turn attention to advanced nanotechnology to address DFU therapeutic bottlenecks. In the last decade, a large number of multifunctional nanosystems based on the microenvironment of DFU have been developed with positive effects in DFU therapy, forming a novel concept of "DFU nanomedicine". However, a systematic overview of DFU nanomedicine is still unavailable in the literature. This review summarizes the microenvironmental characteristics of DFU, presents the main progress of wound healing, and summaries the state-of-the-art therapeutic strategies for DFU. Furthermore, the main challenges and future perspectives in this field are discussed and prospected, aiming to fuel and foster the development of DFU nanomedicines successfully.

Ceria Nanoenzyme-Based Hydrogel with Antiglycative and Antioxidative Performance for Infected Diabetic Wound Healing

Diabetic wound healing still faces a dilemma because of the hostile hyperglycemic, oxidative, and easily-infected wound microenvironment. In addition, advanced glycation end products (AGEs) further impede wound repair by altering the immunological balance. Herein, ceria nanorods with distinctive antiglycative and excellent antioxidative capacities are innovatively introduced into a self-healing and erasable hydrogel, which could reshape the wound microenvironment by expediting hemostasis, inhibiting infection, reducing AGEs, and continuously depleting reactive oxygen species. The remitted oxidative stress and glycosylation synergistically regulate inflammatory responses, and promote revascularization and extracellular matrix deposition, resulting in accelerated diabetic wound repair. This study provides a highly efficient strategy for constructing nanoenzyme-reinforced antiglycative hydrogel that regulates every wound healing stage for diabetic wound management.

Emerging ROS-Modulating Technologies for Augmentation of the Wound Healing Process

Reactive oxygen species (ROS) is considered a double-edged sword. The slightly elevated level of ROS helps in wound healing by inhibiting microbial infection. In contrast, excessive ROS levels in the wound site show deleterious effects on wound healing by extending the inflammation phase. Understanding the ROS-mediated molecular and biomolecular mechanisms and their effect on cellular homeostasis and inflammation thus substantially improves the possibility of exogenously augmenting and manipulating wound healing with the emerging antioxidant therapeutics. This review comprehensively delves into the relationship between ROS and critical phases of wound healing and the processes underpinning antioxidant therapies. The manuscript also discusses cutting-edge antioxidant therapeutics that act via ROS scavenging to enhance chronic wound healing.

Self-assembled hydrogel nanocube for stimuli responsive drug delivery and tumor ablation by phototherapy against breast cancer

The shape and responsiveness of nanoengineered delivery carriers are crucial characteristics for the rapid and efficient delivery of therapeutics. We report on a novel type of micrometer-sized hydrogel particles of controlled shape with dual pH and redox sensitivity for intracellular delivery of anticancer drugs and phototherapy. The cubical HA-DOP-CS-PEG networks with disulfide links are obtained by cross-linking HA-DOP-CS-PEG with cystamine. The pH-triggered hydrogel swelling/shrinkage was not only affords effective doxorubicin release. It also actively provides the endosomal/lysosomal escape, redox-triggered drug release. The hydrogels degrade rapidly to low molecular weight chains in the presence of the typical intracellular concentration of glutathione. Drug-loaded cube particles found to be 12% more cytotoxic. ICG and DOX-loaded hydrogel cubes demonstrate 90% cytotoxicity when incubated with MCF-7 cancer cells for 24 and 48 h, respectively. This approach integrates the advantages of pH sensitivity, enzymatic degradation, and shape-regulated internalization for novel types of "intelligent" three-dimensional networks with programmable behavior for controlled delivery of therapeutics.

Nanomaterials-based drug delivery approaches for wound healing

Abstract:

Wound healing is a complex and dynamic process that requires intricate synchronization between multiple cell types within appropriate extracellular microenvironment. Wound healing process involves four overlapping phases in a precisely regulated manner, consisting of hemostasis, inflammation, proliferation, and maturation. For an effective wound healing all four phases must follow in a sequential pattern within a time frame. Several factors might interfere with one or more of these phases in healing process, thus causing improper or impaired wound healing resulting in non-healing chronic wounds. The complications associated with chronic non-healing wounds, along with the limitations of existing wound therapies, have led to the development and emergence of novel and innovative therapeutic interventions. Nanotechnology presents unique and alternative approaches to accelerate the healing of chronic wounds by the interaction of nanomaterials during different phases of wound healing. This review focuses on recent innovative nanotechnology-based strategies for wound healing and tissue regeneration based on nanomaterials, including nanoparticles, nanocomposites and scaffolds. The efficacy of the intrinsic therapeutic potential of nanomaterials (including silver, gold, zinc oxide, copper, cerium oxide, etc.) and the ability of nanomaterials as carriers (liposomes, hydrogels, polymeric nanomaterials, nanofibers) as therapeutic agents associated with wound-healing applications have also been addressed. The significance of these nanomaterial-based therapeutic interventions for wound healing needs to be highlighted to engage researchers and clinicians towards this new and exciting area of bio-nanoscience. We believe that these recent developments will offer researchers an updated source on the use of nanomaterials as an advanced approach to improve wound healing.

Bioactive Chitosan-Based Organometallic Scaffolds for Tissue Engineering and Regeneration

Captivating achievements in developing advanced hybrid biostructures through integrating natural biopolymers with inorganic materials (e.g., metals and metalloids) have paved the way towards the application of bioactive organometallic scaffolds (OMSs) in tissue engineering and regenerative medicine (TERM). Of various biopolymers, chitosan (CS) has been used widely for the development of bioactive OMSs, in large part due to its unique characteristics (e.g., biocompatibility, biodegradability, surface chemistry, and functionalization potential). In integration with inorganic elements, CS has been used to engineer advanced biomimetic matrices to accommodate both embedded cells and drug molecules and serve as scaffolds in TERM. The use of the CS-based OMSs is envisioned to provide a new pragmatic potential in TERM and even in precision medicine. In this review, we aim to elaborate on recent achievements in a variety of CS/metal, CS/metalloid hybrid scaffolds, and discuss their applications in TERM. We also provide comprehensive insights into the formulation, surface modification, characterization, biocompatibility, and cytotoxicity of different types of CS-based OMSs.

Rhein incorporated silk fibroin hydrogels with antibacterial and anti-inflammatory efficacy to promote healing of bacteria-infected burn wounds

Advanced dressings that can simultaneously prevent bacterial colonization/infection and reduce inflammation are highly desired. A simple strategy was developed to incorporate an anti-inflammatory and antibacterial drug rhein into the structure of silk fibroin (SF) matrix to fabricate a hydrogel dressing. The SF/Rhein hydrogels showed fibrous network nanostructure, high water content (~90%), high water adsorption ability (>2 folds of its own weight), acceptable mechanical strength, biocompatibility and antibacterial properties, suitable as dressings for the treatment of bacterial infected wounds. The SF/Rhein hydrogels enhanced the healing rate of burn wounds by reducing inflammation, expediting angiogenesis, and promoting skin appendages formation, being a promising candidate as wound dressings.

Local anesthetic lidocaine-encapsulated polymyxin-chitosan nanoparticles delivery for wound healing: in vitro and in vivo tissue regeneration

In relieving local pains, lidocaine, one of ester-type local anesthetics, has been used. To develop the lidocaine membranes of enhanced local anesthetic effects, we have designed to establish the composition of wound dressings based on lidocaine chloride (LCH) (anesthetic drug)-loaded chitosan (CS)/polymyxin B sulfate (PMB). The LCH membranes (LCH-CS/PMB) was fabricated by the LCH oxide solutions within the CS/PMB matrix. The influences of different experimental limitations on CS/PMB membrane formations were examined. The double membrane particle sizes were evaluated by scanning electron microscopy (HR-SEM). Additionally, antibacterial efficacy was developed for gram-positive and negative microorganisms. Moreover, we examined in vivo healing of skin wounds formed in mouse models over 16 days. In contrast to the untreated wounds, rapid healing was perceived in the LCH-CS/PMB-treated wound with less damaging. These findings indicate that LCH-CS/PMB-based bandaging materials could be a potential innovative biomaterial for tissue repair and regeneration for wound healing applications in an animal model.

Dendrimer-Functionalized Metal Oxide Nanoparticle-Mediated Self-Assembled Collagen Scaffold for Skin Regenerative Application: Function of Metal in Metal Oxides

Functionalized metal oxide nanoparticles cross-linked collagen scaffolds are widely used in skin regenerative applications because of their enhanced physicochemical and biocompatibility properties. From the safety clinical trials point of view, there are no reports that have compared the effects of functionalized metal oxide nanoparticles mediated collagen scaffolds for in vivo skin regenerative applications. In this work, triethoxysilane-poly (amido amine) dendrimer generation 3 (TES-PAMAM-G₃ or G₃)-functionalized spherical shape metal oxide nanoparticles (MO NPs: ZnO, TiO₂, Fe₃O₄, CeO₂, and SiO₂, size: 12-25 nm) cross-linked collagen scaffolds were prepared by using a self-assembly method. Triple helical conformation, pore size, mechanical strength, and in vitro cell viability of MO-TES-PAMAM-G₃-collagen scaffolds were studied through different methods. The in vivo skin regenerative proficiency of MO-TES-PAMAM-G₃-collagen scaffolds was analyzed by implanting the scaffold on wounds in Wistar albino rats. The results demonstrated that MO-TES-PAMAM-G₃-collagen scaffold showed superior skin regeneration properties than other scaffolds. The skin regenerative efficiency of MO NPs followed the order ZnO > TiO₂ > CeO₂ > SiO₂ > Fe₃O₄ NPs. This result can be attributed to higher mechanical strength, cell viability, and better antibacterial activity of ZnO-TES-PAMAM-G₃-collagen scaffold that leads to accelerate the skin regenerative properties in comparison to other metal oxide based collagen scaffolds.

Photoenhanced Dual-Functional Nanomedicine for Promoting Wound Healing: Shifting Focus from Bacteria Eradication to Host Microenvironment Modulation

Pathogenic bacterial infection has become a serious medical threat to global public health. Once the skin has serious defects, bacterial invasion and the following chain reactions will be a thorny clinical conundrum, which takes a long time to heal. Although various strategies have been used to eradicate bacteria, the treatment which can simultaneously disinfect and regulate the infection-related host responses is rarely reported. Herein, inspired by the host microenvironment, a photoenhanced dual-functional nanomedicine is constructed (Hemin@Phmg-TA-MSN) for localized bacterial ablation and host microenvironment modulation. The "NIR-triggered local microthermal therapy" and positively charged surface endow the nanomedicine with excellent bacterial capture and killing activities. Meanwhile, the nanomedicine exhibits broad-spectrum reactive oxygen species (ROS) scavenging activity via the synergistic effect of hemin and tannic acid with photoenhanced electron and hydrogen transfers. Furthermore, the in vivo experiments demonstrate that the dual-functional nanomedicine not only presents robust bacterial eradication capability, but also triggers the oxidative stress and inflammatory microenvironment regulation. The work not only shows a facile and effective way for infected wound management but also provides a new horizon for designing novel and efficient anti-infection therapy shifting focus from bacteria treatment to host microenvironment modulation.

A Smart Nanoplatform with Photothermal Antibacterial Capability and Antioxidant Activity for Chronic Wound Healing

Chronic wounds, such as the diabetic ulcer wounds have serious effect on people's lives, and can even lead to death. Diabetic ulcer wounds are different from normal wounds and much easier to be infected and induce oxidative stress due to the special surrounding microenvironment, which makes it necessary to prepare materials with antibacterial property and antioxidant activity simultaneously. The molybdenum disulfide-ceria (MoS₂ -CeO₂ ) nanocomposite possesses both the photo-thermal therapy (PTT) antibacterial capability of polyethylene glycol modified molybdenum disulfide nanosheets and the antioxidant activity of cerium dioxide nanoparticles (CeO₂ NPs). By combining the inherent antibacterial activity of CeO₂ NPs, the MoS₂ -CeO₂ nanocomposite exhibits excellent PTT antibacterial capability against both gram-positive and gram-negative bacteria through 808 nm laser treatment, thereby reducing the risk of wound infection. Owing to the abundant oxygen vacancies in CeO₂ NPs, Ce³⁺ and Ce⁴⁺ can transform reversibly which endows MoS₂ -CeO₂ nanocomposite with remarkable antioxidant ability to clear away the excessive reactive oxygen species around the diabetic ulcer wounds and promote wound healing. The results demonstrate that MoS₂ -CeO₂ nanocomposite is a promising class for the clinical treatment of chronic wounds especially the diabetic ulcer wounds, and 808 nm laser can be used as a PTT antibacterial switch.

Application of Polymer Drugs with Cerium Dioxide Nanomolecules and Mesenchymal Stem Cells for the Treatment of Skin Wounds in Aged Rats

The urgency of the problem of wound healing is not in doubt, given the global trend of an increase in the number of operations and injuries with skin damage, as well as the lack of universal means of treating wounds.

STUDY OBJECTIVE

To compare the effectiveness of the developed drugs, smart polymeric nano-drug with cerium oxide nanoparticles (SPN), and smart polymeric nano-drug in combination with mesenchymal stem cells (SPN + SC) on the healing process of skin wounds.

MATERIAL AND METHODS

An experimental study was carried out using Wistar rats of post-reproductive age, which had dermis and epidermis removed on their backs. There were four groups of wounds in total: control, treatment with mesenchymal stem cells (SC), SPN, and SPN + SC.

RESULTS

A positive therapeutic effect of polymeric drugs on the dynamics of wound area reduction was established, which was most typical for wounds of the SPN group and, particularly, the SPN + SC group. On the third day, an anti-inflammatory effect was revealed in the SC and the SPN + SC groups in particular, which was expressed in a reduced leukocyte infiltration and an increase in the level of microcirculation during this period. The fastest transition from the phase of exudation to proliferation was recorded in the SPN and SPN + SC groups. Histologically, these groups showed faster regeneration, including the epithelialization of wounds.

CONCLUSION

The results obtained in the course of the study open up possibilities for the development of fundamentally new, highly effective wound healing agents.

CeO2 Nanoparticle-Containing Polymers for Biomedical Applications: A Review

The development of advanced composite biomaterials combining the versatility and biodegradability of polymers and the unique characteristics of metal oxide nanoparticles unveils new horizons in emerging biomedical applications, including tissue regeneration, drug delivery and gene therapy, theranostics and medical imaging. Nanocrystalline cerium(IV) oxide, or nanoceria, stands out from a crowd of other metal oxides as being a truly unique material, showing great potential in biomedicine due to its low systemic toxicity and numerous beneficial effects on living systems. The combination of nanoceria with new generations of biomedical polymers, such as PolyHEMA (poly(2-hydroxyethyl methacrylate)-based hydrogels, electrospun nanofibrous polycaprolactone or natural-based chitosan or cellulose, helps to expand the prospective area of applications by facilitating their bioavailability and averting potential negative effects. This review describes recent advances in biomedical polymeric material practices, highlights up-to-the-minute cerium oxide nanoparticle applications, as well as polymer-nanoceria composites, and aims to address the question: how can nanoceria enhance the biomedical potential of modern polymeric materials?

In vitro genotoxicity assessment and comparison of cerium (IV) oxide micro- and nanoparticles

Cerium (IV) oxide (CeO₂), which is used as a biomaterial, has wide application in areas such as the biomedical, glass polishing, electronic, automotive, and pharmacology industries. Comparing with the literature, in this study, the genotoxic effects of cerium (IV) oxide microparticles (COMPs) and cerium (IV) oxide nanoparticles (CONPs) were investigated for the first time in human peripheral blood cultures at concentrations of 0.78, 1.56, 3.125, 6.25, 12.5, 25, and 50 ppm for 72 h under in vitro conditions. Particle sizes of COMPs and CONPs were determined using scanning electron microscopic analysis. Micronucleus and chromosome aberration tests were used to determine the genotoxicity of COMPs and CONPs. The average particle sizes of COMPs and CONPs were approximately 148.25 and 25.30 nm, respectively. It was determined that CeO₂ particles in both micro and nano sizes were toxic at all concentrations compared to the negative control group (distilled water). Importantly, COMPs and CONPs were genotoxic even at the lowest concentration (0.78 ppm). Comparing particle sizes, the data indicated that COMPs were more toxic than CONPs. The results suggest that genotoxicity of COMPs and CONPs may be a function of applied concentrations and particle sizes.

Cerium Oxide Nanoparticles (Nanoceria): Hopes in Soft Tissue Engineering

Several biocompatible materials have been applied for managing soft tissue lesions; cerium oxide nanoparticles (CNPs, or nanoceria) are among the most promising candidates due to their outstanding properties, including antioxidant, anti-inflammatory, antibacterial, and angiogenic activities. Much attention should be paid to the physical properties of nanoceria, since most of its biological characteristics are directly determined by some of these relevant parameters, including the particle size and shape. Nanoceria, either in bare or functionalized forms, showed the excellent capability of accelerating the healing process of both acute and chronic wounds. The skin, heart, nervous system, and ophthalmic tissues are the main targets of nanoceria-based therapies, and the other soft tissues may also be evaluated in upcoming experimental studies. For the repair and regeneration of soft tissue damage and defects, nanoceria-incorporated film, hydrogel, and nanofibrous scaffolds have been proven to be highly suitable replacements with satisfactory outcomes. Still, some concerns have remained regarding the long-term effects of nanoceria administration for human tissues and organs, such as its clearance from the vital organs. Moreover, looking at the future, it seems necessary to design and develop three-dimensional (3D) printed scaffolds containing nanoceria for possible use in the concepts of personalized medicine.

Nanosystems for the Encapsulation of Natural Products: The Case of Chitosan Biopolymer as a Matrix

Chitosan is a cationic natural polysaccharide, which has emerged as an increasingly interesting biomaterialover the past few years. It constitutes a novel perspective in drug delivery systems and nanocarriers' formulations due to its beneficial properties, including biocompatibility, biodegradability and low toxicity. The potentiality of chemical or enzymatic modifications of the biopolymer, as well as its complementary use with other polymers, further attract the scientific community, offering improved and combined properties in the final materials. As a result, chitosan has been extensively used as a matrix for the encapsulation of several valuable compounds. In this review article, the advantageous character of chitosan as a matrix for nanosystemsis presented, focusing on the encapsulation of natural products. A five-year literature review is attempted covering the use of chitosan and modified chitosan as matrices and coatings for the encapsulation of natural extracts, essential oils or pure naturally occurring bioactive compounds are discussed.

Microporous Frameworks as Promising Platforms for Antibacterial Strategies Against Oral Diseases

Nowadays, the heavy burden of oral diseases such as dental caries, periodontitis, endodontic infections, etc., and their consequences on the patients' quality of life indicate a strong need for developing effective therapies. Bacterial infections played an important role in the field of oral diseases, in-depth insight of such oral diseases have given rise to the demand for antibacterial therapeutic strategies. Recently, microporous frameworks have attracted tremendous interest in antibacterial application due to their well-defined porous structures for drug delivery. In addition, intensive efforts have been made to enhance the antibacterial performance of microporous frameworks, such as ion doping, photosensitizer incorporation as building blocks, and surface modifications. This review article aims on the major recent developments of microporous frameworks for antibacterial applications against oral diseases. The first part of this paper puts concentration on the cutting-edge researches on the versatile antibacterial strategies of microporous materials via drug delivery, inherent activity, and structural modification. The second part discusses the antibacterial applications of microporous frameworks against oral diseases. The applications of microporous frameworks not only have promising therapeutic potential to inhibit bacterial plaque-initiated oral infectious diseases, but also have a wide applicability to other biomedical applications.

Nanomedicine in Healing Chronic Wounds: Opportunities and Challenges

The poor healing associated with chronic wounds affects millions of people worldwide through high mortality rates and associated costs. Chronic wounds present three main problems: First, the absence of a suitable environment to facilitate cell migration, proliferation, and angiogenesis; second, bacterial infection; and third, unbalanced and prolonged inflammation. Unfortunately, current therapeutic approaches have not been able to overcome these main issues and, therefore, have limited clinical success. Over the past decade, incorporating the unique advantages of nanomedicine into wound healing approaches has yielded promising outcomes. Nanomedicine is capable of stimulating various cellular and molecular mechanisms involved in the wound microenvironment via antibacterial, anti-inflammatory, and angiogenetic effects, potentially reversing the wound microenvironment from nonhealing to healing. This review briefly discusses wound healing mechanisms and pathophysiology and then highlights recent findings regarding the opportunities and challenges of using nanomedicine in chronic wound management.

Efficacy of A Novel Smart Polymeric Nanodrug in the Treatment of Experimental Wounds in Rats

High-quality and aesthetic wound healing, as well as effective medical support of this process, continue to be relevant. This study aims to evaluate the medical efficacy of a novel smart polymeric nanodrug (SPN) on the rate and mechanism of wound healing in experimental animals. The study was carried out in male Wistar rats (aged 8-9 months). In these animals, identical square wounds down to the fascia were made in non-sterile conditions on the back on both sides of the vertebra. SPN was used for the treatment of one wound, and the other wound was left without treatment (control group). Biocompatible citrate-stabilized cerium oxide nanoparticles integrated into a polysaccharide hydrogel matrix containing natural and synthetic polysaccharide polymers (pectin, alginate, chitosan, agar-agar, water-soluble cellulose derivatives) were used as the therapeutic agent. Changes in the wound sizes (area, volume) over time and wound temperature were assessed on Days 0, 1, 3, 5, 7, and 14. Histological examination of the wounds was performed on Days 3, 7, and 14. The study showed that the use of SPN accelerated wound healing in comparison with control wounds by inhibiting the inflammatory response, which was measured by a decreased number of white blood cells in SPN-treated wounds. It also accelerated the development of fibroblasts, with an early onset of new collagen synthesis, which eventually led to the formation of more tender postoperative scars. Thus, the study demonstrated that the use of SPN for the treatment of wounds was effective and promising.

Cerium- and Iron-Oxide-Based Nanozymes in Tissue Engineering and Regenerative Medicine

Nanoparticulate materials displaying enzyme-like properties, so-called nanozymes, are explored as substitutes for natural enzymes in several industrial, energy-related, and biomedical applications. Outstanding high stability, enhanced catalytic activities, low cost, and availability at industrial scale are some of the fascinating features of nanozymes. Furthermore, nanozymes can also be equipped with the unique attributes of nanomaterials such as magnetic or optical properties. Due to the impressive development of nanozymes during the last decade, their potential in the context of tissue engineering and regenerative medicine also started to be explored. To highlight the progress, in this review, we discuss the two most representative nanozymes, namely, cerium- and iron-oxide nanomaterials, since they are the most widely studied. Special focus is placed on their applications ranging from cardioprotection to therapeutic angiogenesis, bone tissue engineering, and wound healing. Finally, current challenges and future directions are discussed.

Novel nanoparticles of cerium-doped zeolitic imidazolate frameworks with dual benefits of antibacterial and anti-inflammatory functions against periodontitis

Novel ZIF-8:Ce nanoparticles provide a unique insight into effective anti-inflammatory and antibacterial platforms for periodontitis treatment.

Biopolymers: Applications in wound healing and skin tissue engineering

Wound is a growing healthcare challenge affecting several million worldwide. Lifestyle disorders such as diabetes increases the risk of wound complications. Effective management of wound is often difficult due to the complexity in the healing process. Addition to the conventional wound care practices, the bioactive polymers are gaining increased importance in wound care. Biopolymers are naturally occurring biomolecules synthesized by microbes, plants and animals with highest degree of biocompatibility. The bioactive properties such as antimicrobial, immune-modulatory, cell proliferative and angiogenic of the polymers create a microenvironment favorable for the healing process. The versatile properties of the biopolymers such as cellulose, alginate, hyaluronic acid, collagen, chitosan etc have been exploited in the current wound care market. With the technological advances in material science, regenerative medicine, nanotechnology, and bioengineering; the functional and structural characteristics of biopolymers can be improved to suit the current wound care demands such as tissue repair, restoration of lost tissue integrity and scarless healing. In this review we highlight on the sources, mechanism of action and bioengineering approaches adapted for commercial exploitation.