Nanostructured polymer scaffold decorated with cerium oxide nanoparticles toward engineering an antioxidant and anti-hypertrophic cardiac patch

Protective Role of Nanoceria-Infused Nanofibrous Scaffold toward Bone Tissue Regeneration with Senescent Cells

The presence of oxidative stress in bone defects leads to delayed regeneration, especially in the aged population and patients receiving cancer treatment. This delay is attributed to the increased levels of reactive oxygen species (ROS) in these populations due to the accumulation of senescent cells. Tissue-engineered scaffolds are emerging as an alternative method to treat bone defects. In this study, we engineered tissue scaffolds tailored to modulate the adverse effects of oxidative stress and promote bone regeneration. We used polycaprolactone to fabricate nanofibrous mats by using electrospinning. We exploited the ROS-scavenging properties of cerium oxide nanoparticles to alleviate the high oxidative stress microenvironment caused by the presence of senescent cells. We characterized the nanofibers for their physical and mechanical properties and utilized an ionization-radiation-based model to induce senescence in bone cells. We demonstrate that the presence of ceria can modulate ROS levels, thereby reducing the level of senescence and promoting osteogenesis. Overall, this study demonstrates that ceria-infused nanofibrous scaffolds can be used for augmenting the osteogenic activity of senescent progenitor cells, which has important implications for engineering bone tissue scaffolds for patients with low regeneration capabilities.

Biosafe cerium oxide nanozymes protect human pluripotent stem cells and cardiomyocytes from oxidative stress

BACKGROUND

Cardiovascular diseases (CVDs) have the highest mortality worldwide. Human pluripotent stem cells (hPSCs) and their cardiomyocyte derivatives (hPSC-CMs) offer a valuable resource for disease modeling, pharmacological screening, and regenerative therapy. While most CVDs are linked to significant over-production of reactive oxygen species (ROS), the effects of current antioxidants targeting excessive ROS are limited. Nanotechnology is a powerful tool to develop antioxidants with improved selectivity, solubility, and bioavailability to prevent or treat various diseases related to oxidative stress. Cerium oxide nanozymes (CeONZs) can effectively scavenge excessive ROS by mimicking the activity of endogenous antioxidant enzymes. This study aimed to assess the nanotoxicity of CeONZs and their potential antioxidant benefits in stressed human embryonic stem cells (hESCs) and their derived cardiomyocytes (hESC-CMs).

RESULTS

CeONZs demonstrated reliable nanosafety and biocompatibility in hESCs and hESC-CMs within a broad range of concentrations. CeONZs exhibited protective effects on the cell viability of hESCs and hESC-CMs by alleviating excessive ROS-induced oxidative stress. Moreover, CeONZs protected hESC-CMs from doxorubicin (DOX)-induced cardiotoxicity and partially ameliorated the insults from DOX in neonatal rat cardiomyocytes (NRCMs). Furthermore, during hESCs culture, CeONZs were found to reduce ROS, decrease apoptosis, and enhance cell survival without affecting their self-renewal and differentiation potential.

CONCLUSIONS

CeONZs displayed good safety and biocompatibility, as well as enhanced the cell viability of hESCs and hESC-CMs by shielding them from oxidative damage. These promising results suggest that CeONZs may be crucial, as a safe nanoantioxidant, to potentially improve the therapeutic efficacy of CVDs and be incorporated into regenerative medicine.

Ceria-Based Therapeutic Antioxidants for Biomedical Applications

The growing interest in nanomedicine over the last 20 years has carved out a research field called "nanocatalytic therapy," where catalytic reactions mediated by nanomaterials are employed to intervene in disease-critical biomolecular processes. Among many kinds of catalytic/enzyme-mimetic nanomaterials investigated thus far, ceria nanoparticles stand out from others owing to their unique scavenging properties against biologically noxious free radicals, including reactive oxygen species (ROS) and reactive nitrogen species (RNS), by exerting enzyme mimicry and nonenzymatic activities. Much effort has been made to utilize ceria nanoparticles as self-regenerating antioxidative and anti-inflammatory agents for various kinds of diseases, given the detrimental effects of ROS and RNS therein that need alleviation. In this context, this review is intended to provide an overview as to what makes ceria nanoparticles merit attention in disease therapy. The introductory part describes the characteristics of ceria nanoparticles as an oxygen-deficient metal oxide. The pathophysiological roles of ROS and RNS are then presented, as well as their scavenging mechanisms by ceria nanoparticles. Representative examples of recent ceria-nanoparticle-based therapeutics are summarized by categorization into organ and disease types, followed by the discussion on the remaining challenges and future research directions.

Essential Role of Anisotropy in Bioengineered Cardiac Tissue Models

As regulatory bodies encourage alternatives to animal testing, there is renewed interest in engineering disease models, particularly for cardiac tissues. The aligned organization of cells in the mammalian heart controls the electrical and ionic currents and its ability to efficiently circulate blood to the body. Although the development of engineered cardiac systems is rising, insights into the topographical aspects, in particular, the necessity to design in vitro cardiac models incorporating cues for unidirectional cell growth, is lacking. This review first summarizes the widely used methods to organize cardiomyocytes (CMs) unidirectionally and the ways to quantify the resulting cellular alignment. The behavior of CMs in response to alignment is described, with emphasis on their functions and underlying mechanisms. Lastly, the limitations of state-of-the-art techniques to modulate CM alignment in vitro and opportunities for further development in the future to improve the cardiac tissue models that more faithfully mimic the pathophysiological hallmarks are outlined. This review serves as a call to action for bioengineers to delve deeper into the in vivo role of cellular organization in cardiac muscle tissue and draw inspiration to effectively mimic in vitro for engineering reliable disease models.

Hydrogels for the Treatment of Myocardial Infarction: Design and Therapeutic Strategies

Cardiovascular diseases (CVDs) have become the leading global burden of diseases in recent years and are the primary cause of human mortality and loss of healthy life expectancy. Myocardial infarction (MI) is the top cause of CVDs-related deaths, and its incidence is increasing worldwide every year. Recently, hydrogels have garnered great interest from researchers as a promising therapeutic option for cardiac tissue repair after MI. This is due to their excellent properties, including biocompatibility, mechanical properties, injectable properties, anti-inflammatory properties, antioxidant properties, angiogenic properties, and conductive properties. This review discusses the advantages of hydrogels as a novel treatment for cardiac tissue repair after MI. The design strategies of various hydrogels in MI treatment are then summarized, and the latest research progress in the field is classified. Finally, the future perspectives of this booming field are also discussed at the end of this review.

Metal-Based Nanoparticles for Cardiovascular Diseases

Globally, cardiovascular diseases (CVDs) are the leading cause of death and disability. While there are many therapeutic alternatives available for the management of CVDs, the majority of classic therapeutic strategies were found to be ineffective at stopping or significantly/additionally slowing the progression of these diseases, or they had unfavorable side effects. Numerous metal-based nanoparticles (NPs) have been created to overcome these limitations, demonstrating encouraging possibilities in the treatment of CVDs due to advancements in nanotechnology. Metallic nanomaterials, including gold, silver, and iron, come in various shapes, sizes, and geometries. Metallic NPs are generally smaller and have more specialized physical, chemical, and biological properties. Metal-based NPs may come in various forms, such as nanoshells, nanorods, and nanospheres, and they have been studied the most. Massive potential applications for these metal nanomaterial structures include supporting molecular imaging, serving as drug delivery systems, enhancing radiation-based anticancer therapy, supplying photothermal transforming effects for thermal therapy, and being compounds with bactericidal, fungicidal, and antiviral qualities that may be helpful for cardiovascular diseases. In this context, the present paper aims to review the applications of relevant metal and metal oxide nanoparticles in CVDs, creating an up-to-date framework that aids researchers in developing more efficient treatment strategies.

Nanoparticle Polymers Influence on Cardiac Health: Good or Bad for Cardiac Physiology?

Cardiovascular diseases (CVD) are one of the leading causes of death and morbidity worldwide. Lifestyle modifications, medications, and addressing epidemiological factors have long been at the forefront of targeting therapeutics for CVD. Treatments can be further complicated given the intersection of gender, age, unique comorbidities, and healthcare access, among many other factors. Therefore, expanding treatment and diagnostic modalities for CVD is absolutely necessary. Nanoparticles and nanomaterials are increasingly being used as therapeutic and diagnostic modalities in various disciplines of biomedicine. Nanoparticles have multiple ways of interacting with the cardiovascular system. Some of them alter cardiac physiology by impacting ion channels, whereas others influence ions directly or indirectly, improving cellular death via decreasing oxidative stress.  While embedding nanoparticles into therapeutics can help enhance healthy cardiovascular function in other scenarios, they can also impair physiology by increasing reactive oxidative species and leading to cardiotoxicity. This review explores different types of nanoparticles, their effects, and the applicable dosages to create a better foundation for understanding the current research findings.

Nanotechnology in coronary heart disease

Coronary heart disease (CHD) is one of the major causes of death and disability worldwide, especially in low- and middle-income countries and among older populations. Conventional diagnostic and therapeutic approaches have limitations such as low sensitivity, high cost and side effects. Nanotechnology offers promising alternative strategies for the diagnosis and treatment of CHD by exploiting the unique properties of nanomaterials. In this review, we use bibliometric analysis to identify research hotspots in the application of nanotechnology in CHD and provide a comprehensive overview of the current state of the art. Nanomaterials with enhanced imaging and biosensing capabilities can improve the early detection of CHD through advanced contrast agents and high-resolution imaging techniques. Moreover, nanomaterials can facilitate targeted drug delivery, tissue engineering and modulation of inflammation and oxidative stress, thus addressing multiple aspects of CHD pathophysiology. We discuss the application of nanotechnology in CHD diagnosis (imaging and sensors) and treatment (regulation of macrophages, cardiac repair, anti-oxidative stress), and provide insights into future research directions and clinical translation. This review serves as a valuable resource for researchers and clinicians seeking to harness the potential of nanotechnology in the management of CHD. STATEMENT OF SIGNIFICANCE: Coronary heart disease (CHD) is the one of leading cause of death and disability worldwide. Nanotechnology offers new strategies for diagnosing and treating CHD by exploiting the unique properties of nanomaterials. This review uses bibliometric analysis to uncover research trends in the use of nanotechnology for CHD. We discuss the potential of nanomaterials for early CHD detection through advanced imaging and biosensing, targeted drug delivery, tissue engineering, and modulation of inflammation and oxidative stress. We also offer insights into future research directions and potential clinical applications. This work aims to guide researchers and clinicians in leveraging nanotechnology to improve CHD patient outcomes and quality of life.

Ceria Nanozyme Coordination with Curcumin for Treatment of Sepsis-induced Cardiac Injury by Inhibiting Ferroptosis and Inflammation

INTRODUCTION

Sepsis-induced cardiac injury is the leading cause of death in patients. Recent studies have reported that reactive oxygen species (ROS)-mediated ferroptosis and macrophage-induced inflammation are the two main key roles in the process of cardiac injury. The combination of ferroptosis and inflammation inhibition is a feasible strategy in the treatment of sepsis-induced cardiac injury.

OBJECTIVES

In the present study, ceria nanozyme coordination with curcumin (CeCH) was designed by a self-assembled method with human serum albumin (HSA) to inhibit ferroptosis and inflammation of sepsis-induced cardiac injury.

METHODS AND RESULTS

The formed CeCH obtained the superoxide dismutase (SOD)-like and catalase (CAT)-like activities from ceria nanozyme to scavenge ROS, which showed a protective effect on cardiomyocytes in vitro. Furthermore, it also showed ferroptosis inhibition to reverse cell death from RSL3-induced cardiomyocytes, denoted from curcumin. Due to the combination therapy of ceria nanozyme and curcumin, the formed CeCH NPs could also promote M2 macrophage polarization to reduce inflammation in vitro. In the lipopolysaccharide (LPS)-induced sepsis model, the CeCH NPs could effectively inhibit ferroptosis, reverse inflammation, and reduce the release of pro-inflammatory factors, which markedly alleviated the myocardial injury and recover the cardiac function.

CONCLUSION

Overall, the simple self-assembled strategy with ceria nanozyme and curcumin showed a promising clinical application for sepsis-induced cardiac injury by inhibiting ferroptosis and inflammation.

Acknowledgments

This study was supported by grants of the National Natural Science Foundation of China (82100398); the Nanjing Medical Science and Technique Development Foundation (YKK21068); Clinical Trials from the Affiliated Drum Tower Hospital, Medical School of Nanjing University (2023-LCYJ-PY-24); the Jiangsu Research Hospital Association for Precision Medication (JY202120); the Jiangsu Pharmaceutical Association for Jinpeiying Project (J2021001); China Postdoctoral Science Foundation (2022M721576).

Stem cell-derived hepatocyte therapy using versatile biomimetic nanozyme incorporated nanofiber-reinforced decellularized extracellular matrix hydrogels for the treatment of acute liver failure

Reactive oxygen species (ROS)-associated oxidative stress, inflammation storm, and massive hepatocyte necrosis are the typical manifestations of acute liver failure (ALF), therefore specific therapeutic interventions are essential for the devastating disease. Here, we developed a platform consisting of versatile biomimetic copper oxide nanozymes (Cu NZs)-loaded PLGA nanofibers (Cu NZs@PLGA nanofibers) and decellularized extracellular matrix (dECM) hydrogels for delivery of human adipose-derived mesenchymal stem/stromal cells-derived hepatocyte-like cells (hADMSCs-derived HLCs) (HLCs/Cu NZs@fiber/dECM). Cu NZs@PLGA nanofibers could conspicuously scavenge excessive ROS at the early stage of ALF, and reduce the massive accumulation of pro-inflammatory cytokines, herein efficiently preventing the deterioration of hepatocytes necrosis. Moreover, Cu NZs@PLGA nanofibers also exhibited a cytoprotection effect on the transplanted HLCs. Meanwhile, HLCs with hepatic-specific biofunctions and anti-inflammatory activity acted as a promising alternative cell source for ALF therapy. The dECM hydrogels further provided the desirable 3D environment and favorably improved the hepatic functions of HLCs. In addition, the pro-angiogenesis activity of Cu NZs@PLGA nanofibers also facilitated the integration of the whole implant with the host liver. Hence, HLCs/Cu NZs@fiber/dECM performed excellent synergistic therapeutic efficacy on ALF mice. This strategy using Cu NZs@PLGA nanofiber-reinforced dECM hydrogels for HLCs in situ delivery is a promising approach for ALF therapy and shows great potential for clinical translation.

Recent theranostic applications of hydrogen peroxide-responsive nanomaterials for multiple diseases

It is well established that hydrogen peroxide (H2O2) is associated with the initiation and progression of many diseases. With the rapid development of nanotechnology, the diagnosis and treatment of those diseases could be realized through a variety of H2O2-responsive nanomaterials. In order to broaden the application prospects of H2O2-responsive nanomaterials and promote their development, understanding and summarizing the design and application fields of such materials has attracted much attention. This review provides a comprehensive summary of the types of H2O2-responsive nanomaterials including organic, inorganic and organic-inorganic hybrids in recent years, and focused on their specific design and applications. Based on the type of disease, such as tumors, bacteria, dental diseases, inflammation, cardiovascular diseases, bone injury and so on, key examples for above disease imaging diagnosis and therapy strategies are introduced. In addition, current challenges and the outlook of H2O2-responsive nanomaterials are also discussed. This review aims to stimulate the potential of H2O2-responsive nanomaterials and provide new application ideas for various functional nanomaterials related to H2O2.

Sustained Delivery of Methylsulfonylmethane from Biodegradable Scaffolds Enhances Efficient Bone Regeneration

Introduction

As a popular dietary supplement containing sulfur compound, methylsulfonylmethane (MSM) has been widely used as an alternative oral medicine to relieve joint pain, reduce inflammation and promote collagen protein synthesis. However, it is rarely used in developing bioactive scaffolds in bone tissue engineering.

Methods

Three-dimensional (3D) hydroxyapatite/poly (lactide-co-glycolide) (HA/PLGA) porous scaffolds with different doping levels of MSM were prepared using the phase separation method. MSM loading efficiency, in vitro drug release as well as the biological activity of MSM-loaded scaffolds were investigated by incubating mouse pre-osteoblasts (MC3T3-E1) in the uniform and interconnected porous scaffolds.

Results

Sustained release of MSM from the scaffolds was observed, and the total MSM release from 1% and 10% MSM/HA/PLGA scaffolds within 16 days was up to 64.9% and 68.2%, respectively. Cell viability, proliferation, and alkaline phosphatase (ALP) activity were significantly promoted by incorporating 0.1% of MSM in the scaffolds. In vivo bone formation ability was significantly enhanced for 1% MSM/HA/PLGA scaffolds indicated by the repair of rabbit radius defects which might be affected by a stimulated release of MSM by enzyme systems in vivo.

Discussion

Finding from this study revealed that the incorporation of MSM would be effective in improving the osteogenesis activity of the HA/PLGA porous scaffolds.

Preparation, Characterization and Multiple Biological Properties of Peptide-Modified Cerium Oxide Nanoparticles

Although cerium oxide nanoparticles are attracting much attention in the biomedical field due to their unique physicochemical and biological functions, the cerium oxide nanoparticles greatly suffer from several unmet physicochemical challenges, including loss of enzymatic activity during the storage, non-specific cellular uptake, off-target toxicities, etc. Herein, in order to improve the targeting property of cerium oxide nanoparticles, we first modified cerium oxide nanoparticles (CeO₂) with polyacrylic acid (PAA) and then conjugated with an endothelium-targeting peptide glycine-arginine-aspartic acid (cRGD) to construct CeO₂@PAA@RGD. The physiochemical characterization results showed that the surface modifications did not impact the intrinsic enzymatic properties of CeO₂, including catalase-like (CAT) and superoxide dismutase-like (SOD) activities. Moreover, the cellular assay data showed that CeO₂@PAA@RGD exhibited a good biocompatibility and a higher cellular uptake due to the presence of RGD targeting peptide on its surface. CeO₂@PAA@RGD effectively scavenged reactive oxygen species (ROS) to protect cells from oxidative-stress-induced damage. Additionally, it was found that the CeO₂@PAA@RGD converted the phenotype of macrophages from proinflammatory (M1) to anti-inflammatory (M2) phenotype, inhibiting the occurrence of inflammation. Furthermore, the CeO₂@PAA@RGD also promoted endothelial cell-mediated migration and angiogenesis. Collectively, our results successfully demonstrate the promising application of CeO₂@PAA@RGD in the future biomedical field.

Myocardial infarction from a tissue engineering and regenerative medicine point of view: A comprehensive review on models and treatments

In the modern world, myocardial infarction is one of the most common cardiovascular diseases, which are responsible for around 18 million deaths every year or almost 32% of all deaths. Due to the detrimental effects of COVID-19 on the cardiovascular system, this rate is expected to increase in the coming years. Although there has been some progress in myocardial infarction treatment, translating pre-clinical findings to the clinic remains a major challenge. One reason for this is the lack of reliable and human representative healthy and fibrotic cardiac tissue models that can be used to understand the fundamentals of ischemic/reperfusion injury caused by myocardial infarction and to test new drugs and therapeutic strategies. In this review, we first present an overview of the anatomy of the heart and the pathophysiology of myocardial infarction, and then discuss the recent developments on pre-clinical infarct models, focusing mainly on the engineered three-dimensional cardiac ischemic/reperfusion injury and fibrosis models developed using different engineering methods such as organoids, microfluidic devices, and bioprinted constructs. We also present the benefits and limitations of emerging and promising regenerative therapy treatments for myocardial infarction such as cell therapies, extracellular vesicles, and cardiac patches. This review aims to overview recent advances in three-dimensional engineered infarct models and current regenerative therapeutic options, which can be used as a guide for developing new models and treatment strategies.

Photocatalytic effect-assisted antimicrobial activities of acrylic resin incorporating zinc oxide nanoflakes

To overcome the deficiency of the antimicrobial effect of polymer, zinc oxide nanoparticles have been widely utilized as advanced nanofillers due to their antimicrobial and photocatalytic activity. However, the underlying antimicrobial mechanism has not been fully understood apart from topological and physical characteristics. In this study, we prepared zinc oxide nanoparticles-based acrylic resin to explore its antimicrobial mechanism under controlled mechanophysical conditions by using silane-treated zinc oxide nanoflakes (S-ZnNFs). S-ZnNFs incorporated acrylic resin (poly(methyl methacrylate), PMMA) composites up to 2 wt% were selected based on comparable mechanophysical properties (e.g., roughness, wettability, strength and hardness), possibly affecting antimicrobial properties beyond the zinc oxide nanoparticle effect, to bare PMMA. Antimicrobial adhesion results were still observed in 2 wt% S-ZnNFs incorporated PMMA using Candida albicans (C. albicans), one of the fungal infection species. In order to confirm the antimicrobial effects by photocatalysis, we pre-exposed the UV light on 2 wt% S-ZnNF composites before cell seeding, revealing synergetic antimicrobial effect via additional reactive oxygen species (ROS) generation to C. albicans over zinc oxide nanoparticle-induced one. RNA-seq analysis revealed distinguished cellular responses between zinc oxide nanoparticles and UV-mediated photocatalytic effect, but both linked to generation of intracellular ROS. Thus, the above data suggest that induction of high intracellular ROS of C. albicans was the main antimicrobial mechanism under controlled mechanophysical parameters and synergetic ROS accumulation can be induced by photocatalysis, recapitulating a promising use of a S-ZnNFs or possibly zinc oxide nanoparticles as intracellular-ROS-generating antimicrobial nanofillers in acrylic composite for biomedical applications.

Cationized silica ceria nanocomposites to target biofilms in chronic wounds

Altered wound healing is a major challenge faced by both developed and developing nations. Biofilm formation has been identified as one of the causative factors for the progression of chronic wounds. The spread of biofilm is controlled by inhibiting the biofilm formation or disrupting the mature biofilm. Functional nanomaterials/enzymes with antimicrobial effects, such as metal oxides, rare earth metals, and carbon nanoparticles have been investigated to treat biofilm and overcome the drawbacks associated with the antibiotic therapy. Cerium oxide nanoparticles (CNPs) have drawn significant attention as a promising antimicrobial agent owing to their antibacterial, enzyme-mimetic, and crystalline properties but they suffer from poor colloidal stability and dispersity in an aqueous environment and size-dependent function. In this work, we have developed a functionalized silica ceria nanocomposite (FSC), as an antibiotic-free system, to treat biofilms. The FSC possesses a high surface area of mesoporous silica nanoparticles (MSNs) combined with the intrinsic antibacterial activity of cerium oxide for biofilm inhibition. The nanocomposite was fabricated using silica and ceria precursors, and it exhibited a high surface area of 436 m²/g and an average particle size of around 450 nm. The physical and chemical properties of nanocomposite were characterized using FTIR, XRD, UV-Vis, BET, EDX, and XPS analysis. It exhibited a potent antioxidant activity (86%), positive haloperoxidase mimetic property, and broad-spectrum antibacterial activities. It showed 99.9% inhibition against S. aureus (Gram-positive) and 81% inhibition against E. coli (Gram-negative) within 12 and 24 h along with the significant inhibition of biofilm formation (80%) as well as the disruptive effect against the established biofilm (77%) of S. aureus. Cell viability assays indicated the proliferative nature of composite in normal basal conditions and increased cell viability (97%) in the presence of oxidative stress. Despite being a cationic nanomaterial, it showed a good hemocompatibility against human blood and caused complete wound closure in mouse fibroblast cell line within 24 h. The functionalized silica ceria nanocomposite developed has a strong potential in chronic wound healing applications.

Modular configurations of living biomaterials incorporating nano-based artificial mediators and synthetic biology to improve bioelectrocatalytic performance: A review

Currently, the industrial application of bioelectrochemical systems (BESs) that are incubated with natural electrochemically active microbes (EABs) is limited due to inefficient extracellular electron transfer (EET) by natural EABs. Notably, recent studies have identified several novel living biomaterials comprising highly efficient electron transfer systems allowing unparalleled proficiency of energy conversion. Introduction of these biomaterials into BESs could fundamentally increase their utilization for a wide range of applications. This review provides a comprehensive assessment of recent advancements in the design of living biomaterials that can be exploited to enhance bioelectrocatalytic performance. Further, modular configurations of abiotic and biotic components promise a powerful enhancement through integration of nano-based artificial mediators and synthetic biology. Herein, recent advancements in BESs are synthesized and assessed, including heterojunctions between conductive nanomaterials and EABs, in-situ hybrid self-assembly of EABs and nano-sized semiconductors, cytoprotection in biohybrids, synthetic biological modifications of EABs and electroactive biofilms. Since living biomaterials comprise a broad range of disciplines, such as molecular biology, electrochemistry and material sciences, full integration of technological advances applied in an interdisciplinary framework will greatly enhance/advance the utility and novelty of BESs. Overall, emerging fundamental knowledge concerning living biomaterials provides a powerful opportunity to markedly boost EET efficiency and facilitate the industrial application of BESs to meet global sustainability challenges/goals.

Current Applications of Polycaprolactone as a Scaffold Material for Heart Regeneration

Despite numerous advances in treatments for cardiovascular disease, heart failure (HF) remains the leading cause of death worldwide. A significant factor contributing to the progression of cardiovascular diseases into HF is the loss of functioning cardiomyocytes. The recent growth in the field of cardiac tissue engineering has the potential to not only reduce the downstream effects of injured tissues on heart function and longevity but also re-engineer cardiac function through regeneration of contractile tissue. One leading strategy to accomplish this is via a cellularized patch that can be surgically implanted onto a diseased heart. A key area of this field is the use of tissue scaffolds to recapitulate the mechanical and structural environment of the native heart and thus promote engineered myocardium contractility and function. While the strong mechanical properties and anisotropic structural organization of the native heart can be largely attributed to a robust extracellular matrix, similar strength and organization has proven to be difficult to achieve in cultured tissues. Polycaprolactone (PCL) is an emerging contender to fill these gaps in fabricating scaffolds that mimic the mechanics and structure of the native heart. In the field of cardiovascular engineering, PCL has recently begun to be studied as a scaffold for regenerating the myocardium due to its facile fabrication, desirable mechanical, chemical, and biocompatible properties, and perhaps most importantly, biodegradability, which make it suitable for regenerating and re-engineering function to the heart after disease or injury. This review focuses on the application of PCL as a scaffold specifically in myocardium repair and regeneration and outlines current fabrication approaches, properties, and possibilities of PCL incorporation into engineered myocardium, as well as provides suggestions for future directions and a roadmap toward clinical translation of this technology.

Nanoparticles Targeting the Molecular Pathways of Heart Remodeling and Regeneration

Cardiovascular diseases are the main cause of death worldwide, a trend that will continue to grow over the next decade. The heart consists of a complex cellular network based mainly on cardiomyocytes, but also on endothelial cells, smooth muscle cells, fibroblasts, and pericytes, which closely communicate through paracrine factors and direct contact. These interactions serve as valuable targets in understanding the phenomenon of heart remodeling and regeneration. The advances in nanomedicine in the controlled delivery of active pharmacological agents are remarkable and may provide substantial contribution to the treatment of heart diseases. This review aims to summarize the main mechanisms involved in cardiac remodeling and regeneration and how they have been applied in nanomedicine.

Surface-Engineered Hybrid Gelatin Methacryloyl with Nanoceria as Reactive Oxygen Species Responsive Matrixes for Bone Therapeutics

Designing various transplantable biomaterials, especially nanoscale matrixes for bone regeneration, involves precise tuning of topographical features. The cellular fate on such engineered surfaces is highly influenced by many factors imparted by the surface modification (hydrophilicity, stiffness, porosity, roughness, ROS responsiveness). Herein, hybrid matrixes of gelatin methacryloyl (GelMA) decorated with uniform layers of nanoceria (nCe), called Ce@GelMA, were developed without direct incorporation of nCe into the scaffolds. The fabrication involves a simple base-mediated in situ deposition in which uniform nCe coatings were first made on GelMA hydrogels and then nCe layered GelMA scaffolds were made by cryodesiccation. In this hybrid platform, degradable GelMA biopolymer provides the porous microstructure and nCe provides the nanoscaled biointerface. The surface morphology and elemental composition of the matrixes analyzed by field emission scanning electron microscopy (FE-SEM) and energy-dispersive spectroscopy (EDS) show uniform nCe distribution. The surface nanoroughness and chemistry of the matrixes were also characterized using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The presence of nCe on GelMA enhanced its mechanical properties as confirmed by compressive modulus analysis. Substantial bonelike nanoscale hydroxyapatite formation was observed on scaffolds after simulated body fluid (SBF) immersion, which was confirmed by SEM, X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy. Moreover, the developed scaffolds could also be used as an antioxidant matrix owing to the reactive oxygen species (ROS) scavenging property of nCe as assessed by 3,3',5,5'-tetramethylbenzidine (TMB) assay. The enhanced proliferation and viability of rat bone marrow mesenchymal stem cells (rMSCs) on the scaffold surface after 3 days of culture ensures the biocompatibility of the proposed material. Considering all, it is proposed that the micro/nanoscaled matrix could mimic the composition and function of hard tissues and could be utilized as degradable scaffolds in engineering bones.

Reactive Oxygen Species-Based Biomaterials for Regenerative Medicine and Tissue Engineering Applications

Reactive oxygen species (ROS), acting as essential mediators in biological system, play important roles in the physiologic and pathologic processes, including cellular signal transductions and cell homeostasis interference. Aberrant expression of ROS in tissue microenvironment can be caused by the internal/external stimuli and tissue injury, which may leads to an elevated level of oxidative stress, inflammatory response, and cellular damage as well as disruption in the tissue repair process. To prevent the formation of excess ROS around the injury site, advanced biomaterials can be remodeled or instructed to release their payloads in an injury microenvironment-responsive fashion to regulate the elevated levels of the ROS, which may also help downregulate the oxidative stress and promote tissue regeneration. A multitude of scaffolds and bioactive cues have been reported to promote the regeneration of damaged tissues based on the scavenging of free radicals and reactive species that confer high protection to the cellular activity and tissue function. In this review, we outline the underlying mechanism of ROS generation in the tissue microenvironment and present a comprehensive review of ROS-scavenging biomaterials for regenerative medicine and tissue engineering applications, including soft tissues regeneration, bone and cartilage repair as well as wound healing. Additionally, we highlight the strategies for the regulation of ROS by scaffold design and processing technology. Taken together, developing ROS-based biomaterials may not only help develop advanced platforms for improving injury microenvironment but also accelerate tissue regeneration.

Tunable Biomaterials for Myocardial Tissue Regeneration: Promising New Strategies for Advanced Biointerface Control and Improved Therapeutic Outcomes

Following myocardial infarction (MI) and the natural healing process, the cardiac mechanostructure changes significantly leading to reduced contractile ability and putting additional pressure on the heart muscle thereby increasing the...

Surface Decoration of Redox-Modulating Nanoceria on 3D-Printed Tissue Scaffolds Promotes Stem Cell Osteogenesis and Attenuates Bacterial Colonization

Oxidative stress at the bone defect site delays the bone regeneration process. Increased level of reactive oxygen species (ROS) is the primary cause of oxidative stress at the damaged site. Bone tissue scaffolds that scavenge ROS offer a potential and yet unexplored route for faster bone healing. Cerium oxide (ceria) is known for its redox-modulating behavior. Three-dimensional (3D)-printed porous scaffolds fabricated from degradable polymers provide a physical microenvironment but lack the bioactivity for tissue regeneration. In this work, porous poly(lactic acid) (PLA) scaffolds were prepared by 3D printing and modified with poly(ethylene imine) and citric acid to decorate with ceria nanoparticles. Scanning electron micrographs revealed a macroporous architecture decorated with ceria particles. The compressive modulus of 27 MPa makes them suitable for trabecular bone. The scaffolds supported human mesenchymal stem cell growth, confirming cytocompatibility. The ability to scavenge ROS confirmed that surface functionalization with ceria could reduce oxidative stress levels in the cells. Stem cell osteogenesis was enhanced after ceria decoration of the PLA scaffolds. Transcriptional profiling studied by sequencing revealed changes in the expression of genes associated with inflammation and cell-material interactions. The ceria-functionalized scaffolds show enhanced antibacterial activity against both Gram-negative and Gram-positive bacterial strains. These results demonstrate that surface decoration with nanoceria offers a viable route for enhancing the bioactivity of 3D-printed PLA scaffolds for bone tissue regeneration with ROS scavenging and antibacterial capability.

Zinc and cerium synergistically enhance the mechanical properties, corrosion resistance, and osteogenic activity of magnesium as resorbable biomaterials

Magnesium and its alloys have the potential to serve as a revolutionary class of biodegradable materials, specifically in the field of degradable implants for orthopedics. However, the corrosion rate of commercially pure magnesium is high and does not match the rate of regeneration of bone tissues. In this work, magnesium alloys containing zinc and cerium, either alone or in combination, were investigated and compared with commercially-pure magnesium as biomaterials. The microstructure, mechanical properties, corrosion resistance, and response of osteoblastsin vitrowere systematically assessed. Results reveal that alloying with Ce results in grain refinement and weakening of texture. The tensile test revealed that the ternary alloy offered the best combination of elastic modulus (41.1 ± 0.5 GPa), tensile strength (234.5 ± 4.5 MPa), and elongation to break (17.1 ± 0.4%). The ternary alloy was also the most resistant to corrosion (current of 0.85 ± 0.05 × 10^-4A cm^-2) in simulated body fluid than the other alloys. The response of MC3T3-E1 cellsin vitrorevealed that the ternary alloy imparts minimal cytotoxicity. Interestingly, the ternary alloy was highly efficient in supporting osteogenic differentiation, as revealed by the expression of alkaline phosphatase and calcium deposition. In summary, the extruded Mg alloy containing both Zn and Ce exhibits a combination of mechanical properties, corrosion resistance, and cell response that is highly attractive for engineering biodegradable orthopedic implants.

Self-Adhesion Conductive Sub-micron Fiber Cardiac Patch from Shape Memory Polymers to Promote Electrical Signal Transduction Function

Myocardial infarction (MI) constitutes the first cause of morbidity and mortality in our life, so using highly conductive and elastic materials to produce an engineered cardiac patch is an effective way to improve the myocardium infarction area function. Here, shape memory polymers of the polyurethane/polyaniline/silicon oxide (PU/PANI/SiO₂) electrospinning sub-micron fiber patch were precisely produced in the case of the hydrogen bonding effect and interaction between the carboxyl groups to provide compatibility, phase mixing/miscibility, and stability. The sub-micron fiber patch prepared by our group has some remarkable characteristics, such as sub-micron fibers, 3D porous structure, special thickness to simulate the extracellular matrix (ECM), elastic deformation, good properties in conducting weak electrical signals, stability to maintain the whole structure, and self-adhesion. This sub-micron fiber material has been proven to be effective, easy, and reliable. Through precise design of the material system, structure regulation, and performance optimization, the aim is to produce a sub-micron fiber cardiac patch to simulate the myocardium ECM and improve conductive signal transduction for potential MI therapy.

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?

Engineering next-generation bioinks with nanoparticles: moving from reinforcement fillers to multifunctional nanoelements

The application of additive manufacturing in the biomedical field has become a hot topic in the last decade owing to its potential to provide personalized solutions for patients. Different bioinks have been designed trying to obtain a unique concoction that addresses all the needs for tissue engineering and drug delivery purposes, among others. Despite the remarkable progress made, the development of suitable bioinks which combine printability, cytocompatibility, and biofunctionality is still a challenge. In this sense, the well-established synthetic and functionalization routes to prepare nanoparticles with different functionalities make them excellent candidates to be combined with polymeric systems in order to generate suitable multi-functional bioinks. In this review, we briefly discuss the most recent advances in the design of functional nanocomposite hydrogels considering their already evaluated or potential use as bioinks. The scientific development over the last few years is reviewed, focusing the discussion on the wide range of functionalities that can be incorporated into 3D bioprinted constructs through the addition of multifunctional nanoparticles in order to increase their regenerative potential in the field of tissue engineering.

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.