Gold Nanoparticle-Integrated Scaffolds for Tissue Engineering and Regenerative Medicine

Engineering functional electroconductive hydrogels for targeted therapy in myocardial infarction repair

Myocardial infarction (MI) is characterized by a paucity of cardiomyocyte regeneration, leading to significant morbidity and mortality. Contemporary therapeutic modalities, while mitigating ischemic effects, fail to reconstitute the impaired electromechanical coupling within the infracted myocardium. Emerging evidence supports the utility of electroconductive hydrogels (ECHs) in facilitating post-MI cardiac function recovery by restoring the conductive microenvironment of the infarcted tissue. This comprehensive review delineates the taxonomy of ECHs predicated on their constituent conductive materials. It also encapsulates prevailing research trends in ECH-mediated MI repair, encompassing innovative design paradigms and microenvironment-sensitive strategies. The review also provides a critical appraisal of various implantation techniques, underscored by a thorough examination of the attendant considerations. It elucidates the mechanistic underpinnings by which hydrogels exert salutary effects on myocardial repair, namely by augmenting mechanical and electrical integrity, exerting anti-inflammatory actions, fostering angiogenesis, and curtailing adverse remodeling processes. Furthermore, the review engages with the pressing challenge of optimizing ECH functionality to achieve superior reparative outcomes post-MI. The discourse concludes with an anticipatory perspective on the evolution of ECH scaffolds, advocating for a tailored approach that integrates multifaceted physicochemical properties to cater to the nuances of personalized medicine.

Gold nanoparticles modulate macrophage polarization to promote skeletal muscle regeneration

Skeletal muscle regeneration is a complex process that depends on the interplay between immune responses and muscle stem cell (MuSC) activity. Macrophages play a crucial role in this process, exhibiting distinct polarization states-M1 (pro-inflammatory) and M2 (anti-inflammatory)-that significantly affect tissue repair outcomes. Recent advancements in nanomedicine have positioned gold nanoparticles (Au NPs) as promising tools for modulating macrophage polarization and enhancing muscle regeneration. This review examines the role of Au NPs in influencing macrophage behavior, focusing on their physicochemical properties, biocompatibility, and mechanisms of action. We discuss how Au NPs can promote M2 polarization, facilitating tissue repair through modulation of cytokine production, interaction with cell surface receptors, and activation of intracellular signaling pathways. Additionally, we highlight the benefits of Au NPs on MuSC function, angiogenesis, and extracellular matrix remodeling. Despite the potential of Au NPs in skeletal muscle regeneration, challenges remain in optimizing nanoparticle design, developing targeted delivery systems, and understanding long-term effects. Future directions should focus on personalized medicine approaches and combination therapies to enhance therapeutic efficacy. Ultimately, this review emphasizes the transformative potential of Au NPs in regenerative medicine, offering hope for improved treatments for muscle injuries and diseases.

MXenes in healthcare: transformative applications and challenges in medical diagnostics and therapeutics

MXenes, a novel class of two-dimensional transition metal carbides, exhibit exceptional physicochemical properties that make them highly promising for biomedical applications. Their application has been explored in bioinstrumentation, tissue engineering, and infectious disease management. In bioinstrumentation, MXenes enhance the sensitivity and response time of wearable sensors, including piezoresistive, electrochemical, and electrophysiological sensors. They also function effectively as contrast agents in MRI and CT imaging for cancer diagnostics and therapy. In tissue engineering, MXenes contribute to both hard and soft tissue regeneration, playing a key role in neural, cardiac, skin and bone repair. Additionally, they offer innovative solutions in combating infectious and inflammatory diseases by facilitating antimicrobial surfaces and immune modulation. Despite their potential, several challenges hinder the clinical translation of MXene-based technologies. Issues related to synthesis, scalability, biocompatibility, and long-term safety must be addressed to ensure their practical implementation in medical applications. This review provides a comprehensive overview of MXenes in next-generation medical diagnostics, including the role they play in wearable sensors and imaging contrast agents. It further explores their applications in tissue engineering and infectious disease management, highlighting their antimicrobial and immunomodulatory properties. Finally, we discuss the key barriers to clinical translation and propose strategies for overcoming these limitations. This review aims to bridge current advancements with future opportunities for integration of MXenes in healthcare.

A review of recent progress in alginate-based nanocomposite materials for tissue engineering applications

Integrating nanotechnology with tissue engineering has revolutionized biomedical sciences, enabling the development of advanced therapeutic strategies. Tissue engineering applications widely utilize alginate due to its biocompatibility, mild gelation conditions, and ease of modification. Combining different nanomaterials with alginate matrices enhances the resulting nanocomposites' physicochemical properties, such as mechanical, electrical, and biological properties, as well as their surface area-to-volume ratio, offering significant potential for tissue engineering applications. This review thoroughly overviews various nanomaterials, such as metal and metal oxide nanoparticles, carbon-based nanomaterials, MXenes, and hydroxyapatite, that modify alginate-based nanocomposites. It covers multiple preparation techniques, including layer-by-layer assembly, blending, 3D printing, and in situ synthesis. These techniques apply to tissue engineering applications, including bone tissue engineering, cardiac tissue engineering, neural tissue engineering, wound healing, and skin regeneration. Additionally, it highlights current advancements, challenges, and future perspectives.

Hybrid hydrogels containing gradients in gold nanoparticles for localized delivery of mesenchymal stem cells and enhanced nerve tissues remodeling in vivo

Currently, most peripheral nerve injuries are incurable mainly due to excessive reactive oxygen species (ROS) generation in inflammatory tissues, which can further exacerbate localized tissue injury and cause chronic diseases. Although promising for promoting nerve regeneration, stem cell therapy still suffers from abundant intrinsic limitations, mainly including excessive ROS in lesions and inefficient production of growth factors (GFs). Biomaterials that scavenge endogenous ROS and promote GFs secretion might overcome such limitations and thus are being increasingly investigated. Herein, firstly reported as specific ROS scavenging agents and paracrine stimulators, gold nanoparticles (GNPs) were incorporated in the chitosan/polyvinyl alcohol hydrogel networks. The GNPs/hydrogel composite can support the survival of mesenchymal stem cells (MSCs) with excellent expansion efficiency and protect MSCs in a simulated ROS microenvironment, decreasing the intracellular ROS levels and simultaneously enhancing cell viability. Moreover, biodegradable scaffolds, along with MSCs, were implanted into sciatic nerve defects in a rat model to show good application value in vivo. Our work demonstrated that the GNPs/hydrogel shows great promise in MSCs therapy for peripheral nerve injury with convincing biological evidence.

Biomimetic Versatile Anisotropic, Electroactive Cellulose Hydrogel Scaffolds Tailored from Fern Stem Serving as Nerve Conduit and Cardiac Patch

Peripheral nerve injury (PNI) and myocardial infarction (MI) are the two most clinically common soft excitable tissue injuries. Both nerve and cardiac tissues exhibit structural anisotropy and electrophysiological activity, providing a wide range of biophysical cues for cell and tissue repair. However, balancing microstructural anisotropy, electroactivity, and biocompatibility is challenging. To address this issue, Dicranopteris linearis (D. linearis) is proposed as a low-perceived value fern plant. Moreover, to enhance its usefulness, it can be designed into a tubular structure and a lamellar structure to bridge the damaged tissue. Therefore, a robust yet simple top-down approach is proposed to designing and fabricating the desired biomimetic versatile hydrogels orienting from the D. linearis to customize for different soft excitable tissue repair applications. These anisotropic electroactive hydrogels performed well as nerve guidance conduits (NGC) and engineered cardiac patches (ECP) in the repair of PNI and MI, respectively. Two birds, one stone. Accordingly, the biomimetic strategy of D. linearis to NGC and D. linearis to ECP is first proposed, opening a new horizon for constructing tissue engineering using natural sources.

Microcomputed Tomography for the Microstructure Evaluation of 3D Bioprinted Scaffolds

This study implemented the application of microcomputed tomography (micro-CT) as a characterization technique for the study and investigation of the microstructure of 3D scaffold structures produced via three-dimensional bioprinting (3DBP). The study focused on the preparation, characterization, and cytotoxicity analysis of gold nanoparticles (Au-NPs) incorporated into 3DBP hydrogels for micro-CT evaluation. The Au-NPs were characterized by using various techniques, including UV-vis spectrometry, dynamic light scattering (DLS), zeta potential measurement, and transmission electron microscopy (TEM). The characterization results confirmed the successful coating of the Au-NPs with 2 kDa methoxy-PEG and revealed their spherical shape with a mean core diameter of 66 nm. Cytotoxicity analysis using live-dead fluorescent microscopy indicated that all tested Au-NP solutions were nontoxic to AC16 cardiomyocytes in both 2D and 3D culture conditions. Scanning electron microscopy (SEM) showed distinguishable differences in image contrast and intensity between samples with and without Au-NPs, with high concentrations of Au-NPs displaying nanoparticle aggregates. Micro-CT imaging demonstrated that scaffolds containing Au-NPs depicted enhanced imaging resolution and quality, allowing for visualization of the microstructure. The 3D reconstruction of scaffold structures from micro-CT imaging using Dragonfly software further supported the improved visualization. Mechanical analysis revealed that the addition of Au-NPs enhanced the mechanical properties of acellular scaffolds, including their elastic moduli and complex viscosity, but the presence of cells led to biodegradation and reduced mechanical strength. These findings highlight the successful preparation and characterization of Au-NPs, their nontoxic nature in both 2D and 3D culture conditions, their influence on imaging quality, and the impact on the mechanical properties of 3D-printed hydrogels. These results contribute to the development of functional and biocompatible materials for tissue engineering and regenerative medicine applications.

Sulfhydryl functionalized chitosan-covalent organic framework composites for highly efficient and selective recovery of gold from complex liquids

Developing candidate adsorbents with high capacity and selectivity for adsorption is a critical approach to recover gold from secondary sources such as electronic waste (e-waste). This measure not only contributes to the recycling of valuable resources but also benefits environment protection and mitigates the detriment to the ecosystem. Traditional covalent organic frameworks (COFs) have garnered great potential in various fields owing to their unique structures and innate functional sites. However, the construction of specific functionalized COFs and their application in efficient gold extraction are still in their nascent stages. Herein, inspired by the photo-induced thiol-ene click reaction, a novel chitosan-modified COFs material (DhaTab-V@chitosan-SH) was first demonstrated by choosing a precursor COF (DhaTab-V) abundant with vinyl groups to crosslink with a thiol-functionalized chitosan (chitosan-SH). Significantly, the coexistence of imine, amide, hydroxyl and thioether groups in the skeleton could serve as functional adsorption sites to combine with the Au (III) via electrostatic interaction and coordination, imparting DhaTab-V@chitosan-SH with prominent adsorption potential for swift, selective and efficient gold capture (970.15 mg·g-1). Additionally, DhaTab-V@chitosan-SH exhibited superior reusability, and realized real gold capture from the leaching solution of e-waste.

Multiple applications of metal-organic frameworks (MOFs) in the treatment of orthopedic diseases

Pharmacologic treatment of orthopedic diseases is a common challenge for clinical orthopedic surgeons, and as an important step in the stepwise treatment of orthopedic diseases, it is often difficult to achieve satisfactory results with existing pharmacologic treatments. Therefore, it is increasingly important to find new ways to effectively improve the treatment pattern of orthopedic diseases as well as to enhance the therapeutic efficacy. It has been found that metal-organic frameworks (MOFs) possess the advantages of high specific surface area, high porosity, chemical stability, tunability of structure and biocompatibility. Therefore, MOFs are expected to improve the conventional traditional treatment modality for bone diseases. This manuscript reviewed the applications of MOFs in the treatment of common clinical bone diseases and look forward to its future development.

Superior Single-Entity Electrochemistry Performance of Capping Agent-Free Gold Nanoparticles Compared to Citrate-Capped Gold Nanoparticles

In observing the electrocatalytic current of nanoparticles (NPs) using single-entity electrochemistry (SEE), the surface state of the NPs significantly influences the SEE signal. This study investigates the influence of capping agents on the electrocatalytic properties of gold (Au) NPs using SEE. Two inner-sphere reactions, hydrazine oxidation and glucose oxidation, were chosen to explore the SEE characteristics of Au NPs based on the capping agent presence. The results revealed that "capping agent-free" Au NPs exhibited signal magnitudes and frequencies consistent with theoretical expectations, indicating superior stability and catalytic performance in electrolyte solutions. In contrast, citrate-capped Au NPs showed signals varying depending on the applied potential, with larger magnitudes and lower frequencies than expected, likely due to an aggregation of NPs. This study suggests that capping agents play a crucial role in the catalytic performance and stability of Au NPs in SEE. By demonstrating that minimizing capping agent presence can enhance effectiveness in SEE, it provides insights into the future applications of NPs, particularly highlighting their potential as nanocatalysts in energy conversion reactions and environmental applications.

Fundamental characteristics of ultrasonic green formulations using Avena sativa L. extract-mediated gold nanoparticles and electroconductive nanofibers for cardiovascular nursing care

In the pursuit of novel approaches to address chronic heart failure and enhance cardiovascular nursing care, environmentally sustainable nanomaterials have taken center stage. Recent progress in regenerative medicine has opened doors for the use of biocompatible biomaterials that provide mechanical support to damaged heart tissue and facilitate electrical signaling. This study was dedicated to developing advanced electroconductive nanofibers by incorporating eco-friendly Avena sativa L. extract-mediated gold nanoparticles (AuNPs) into polyaniline to create an intricate cardiac patch. The AuNPs were synthesized through an environmentally friendly chemical process aided by ultrasonic conditions. Comprehensive physicochemical analyses, such as UV-Vis spectroscopy, SEM, TEM, DPPH assay, and XRD, were carried out to characterize the AuNPs. These AuNPs were then blended with a polycaprolactone/gelatin polymeric solution and electrospun to fabricate cardiac patches, which underwent thorough evaluation using various techniques. The resulting cardiac patch demonstrated excellent hemocompatibility, antioxidant properties, and cytocompatibility, offering a promising therapeutic approach for myocardial infarctions and the advancement of cardiovascular nursing care.

Gold-Hydrogel Nanocomposites for High-Resolution Laser-Based 3D Printing of Scaffolds with SERS-Sensing Properties

Although visible light-based stereolithography (SLA) represents an affordable technology for the rapid prototyping of 3D scaffolds for in vitro support of cells, its potential could be limited by the lack of functional photocurable biomaterials that can be SLA-structured at micrometric resolution. Even if innovative photocomposites showing biomimetic, bioactive, or biosensing properties have been engineered by loading inorganic particles into photopolymer matrices, main examples rely on UV-assisted extrusion-based low-resolution processes. Here, SLA-printable composites were obtained by mixing a polyethylene glycol diacrylate (PEGDA) hydrogel with multibranched gold nanoparticles (NPs). NPs were engineered to copolymerize with the PEGDA matrix by implementing a functionalization protocol involving covalent grafting of allylamine molecules that have C═C pendant moieties. The formulations of gold nanocomposites were tailored to achieve high-resolution fast prototyping of composite scaffolds via visible light-based SLA. Furthermore, it was demonstrated that, after mixing with a polymer and after laser structuring, gold NPs still retained their unique plasmonic properties and could be exploited for optical detection of analytes through surface-enhanced Raman spectroscopy (SERS). As a proof of concept, SERS-sensing performances of 3D printed plasmonic scaffolds were successfully demonstrated with a Raman probe molecule (e.g., 4-mercaptobenzoic acid) from the perspective of future extensions to real-time sensing of cell-specific markers released within cultures. Finally, biocompatibility tests preliminarily demonstrated that embedded NPs also played a key role by inducing physiological cell-cytoskeleton rearrangements, further confirming the potentialities of such hybrid nanocomposites as groundbreaking materials in laser-based bioprinting.

From electricity to vitality: the emerging use of piezoelectric materials in tissue regeneration

The unique ability of piezoelectric materials to generate electricity spontaneously has attracted widespread interest in the medical field. In addition to the ability to convert mechanical stress into electrical energy, piezoelectric materials offer the advantages of high sensitivity, stability, accuracy and low power consumption. Because of these characteristics, they are widely applied in devices such as sensors, controllers and actuators. However, piezoelectric materials also show great potential for the medical manufacturing of artificial organs and for tissue regeneration and repair applications. For example, the use of piezoelectric materials in cochlear implants, cardiac pacemakers and other equipment may help to restore body function. Moreover, recent studies have shown that electrical signals play key roles in promoting tissue regeneration. In this context, the application of electrical signals generated by piezoelectric materials in processes such as bone healing, nerve regeneration and skin repair has become a prospective strategy. By mimicking the natural bioelectrical environment, piezoelectric materials can stimulate cell proliferation, differentiation and connection, thereby accelerating the process of self-repair in the body. However, many challenges remain to be overcome before these concepts can be applied in clinical practice, including material selection, biocompatibility and equipment design. On the basis of the principle of electrical signal regulation, this article reviews the definition, mechanism of action, classification, preparation and current biomedical applications of piezoelectric materials and discusses opportunities and challenges for their future clinical translation.

Biomaterials for extrusion-based bioprinting and biomedical applications

Amongst the range of bioprinting technologies currently available, bioprinting by material extrusion is gaining increasing popularity due to accessibility, low cost, and the absence of energy sources, such as lasers, which may significantly damage the cells. New applications of extrusion-based bioprinting are systematically emerging in the biomedical field in relation to tissue and organ fabrication. Extrusion-based bioprinting presents a series of specific challenges in relation to achievable resolutions, accuracy and speed. Resolution and accuracy in particular are of paramount importance for the realization of microstructures (for example, vascularization) within tissues and organs. Another major theme of research is cell survival and functional preservation, as extruded bioinks have cells subjected to considerable shear stresses as they travel through the extrusion apparatus. Here, an overview of the main available extrusion-based printing technologies and related families of bioprinting materials (bioinks) is provided. The main challenges related to achieving resolution and accuracy whilst assuring cell viability and function are discussed in relation to specific application contexts in the field of tissue and organ fabrication.

Gold Recovery from E-Waste by Food-Waste Amyloid Aerogels

Demand for gold recovery from e-waste grows steadily due to its pervasive use in the most diverse technical applications. Current methods of gold recovery are resource-intensive, necessitating the development of more efficient extraction materials. This study explores protein amyloid nanofibrils (AF) derived from whey, a dairy industry side-stream, as a novel adsorbent for gold recovery from e-waste. To do so, AF aerogels are prepared and assessed against gold adsorption capacity and selectivity over other metals present in waste electrical and electronic equipment (e-waste). The results demonstrate that AF aerogel has a remarkable gold adsorption capacity (166.7 mg g-1) and selectivity, making it efficient and an adsorbent for gold recovery. Moreover, AF aerogels are efficient templates to convert gold ions into single crystalline flakes due to Au growth along the (111) plane. When used as templates to recover gold from e-waste solutions obtained by dissolving computer motherboards in suitable solvents, the process yields high-purity gold nuggets, constituted by ≈90.8 wt% gold (21-22 carats), with trace amounts of other metals. Life cycle assessment and techno-economic analysis of the process finally consolidate the potential of protein nanofibril aerogels from food side-streams as an environmentally friendly and economically viable approach for gold recovery from e-waste.

Advances in electroactive bioscaffolds for repairing spinal cord injury

Spinal cord injury (SCI) is a devastating neurological disorder, leading to loss of motor or somatosensory function, which is the most challenging worldwide medical problem. Re-establishment of intact neural circuits is the basis of spinal cord regeneration. Considering the crucial role of electrical signals in the nervous system, electroactive bioscaffolds have been widely developed for SCI repair. They can produce conductive pathways and a pro-regenerative microenvironment at the lesion site similar to that of the natural spinal cord, leading to neuronal regeneration and axonal growth, and functionally reactivating the damaged neural circuits. In this review, we first demonstrate the pathophysiological characteristics induced by SCI. Then, the crucial role of electrical signals in SCI repair is introduced. Based on a comprehensive analysis of these characteristics, recent advances in the electroactive bioscaffolds for SCI repair are summarized, focusing on both the conductive bioscaffolds and piezoelectric bioscaffolds, used independently or in combination with external electronic stimulation. Finally, thoughts on challenges and opportunities that may shape the future of bioscaffolds in SCI repair are concluded.

A comprehensive review on the biomedical frontiers of nanowire applications

This comprehensive review examines the immense capacity of nanowires, nanostructures characterized by unbounded dimensions, to profoundly transform the field of biomedicine. Nanowires, which are created by combining several materials using techniques such as electrospinning and vapor deposition, possess distinct mechanical, optical, and electrical properties. As a result, they are well-suited for use in nanoscale electronic devices, drug delivery systems, chemical sensors, and other applications. The utilization of techniques such as the vapor-liquid-solid (VLS) approach and template-assisted approaches enables the achievement of precision in synthesis. This precision allows for the customization of characteristics, which in turn enables the capability of intracellular sensing and accurate drug administration. Nanowires exhibit potential in biomedical imaging, neural interfacing, and tissue engineering, despite obstacles related to biocompatibility and scalable manufacturing. They possess multifunctional capabilities that have the potential to greatly influence the intersection of nanotechnology and healthcare. Surmounting present obstacles has the potential to unleash the complete capabilities of nanowires, leading to significant improvements in diagnostics, biosensing, regenerative medicine, and next-generation point-of-care medicines.

PDMS nanoparticles-decorated PDMS substrate promotes adhesion, proliferation and differentiation of skin cells

Polydimethylsiloxane (PDMS) is known to be a common substrate for various cell culture-based applications. However, native PDMS is not very conducive for cell culture and hence, surface modification via cell adhesion moieties is generally needed to make it suitable especially for long-term cell culture. To address this issue, we propose to coat PDMS nanoparticles (NPs) on the surface of PDMS film to improve adhesion, proliferation and differentiation of skin cells. The proposed modification strategy introduces necessary nanotopography without altering the surface chemical properties of PDMS. Due to resemblance in the mechanical properties of PDMS with skin, PDMS NPs can recreate the native extracellular nanoenvironment of skin on the PDMS surface and provide anchoring sites for skin cells to adhere and grow. Human keratinocytes, representing 95% of the epidermal skin cells maintained their characteristic well-spread morphology with the formation of interconnected cell-sheets on this coated PDMS surface. Moreover, our in vitro immunofluorescence studies confirmed expression of distinctive epidermal protein markers on the coated surface indicating close resemblance with the native skin epidermis. Conclusively, our findings suggest that introducing nanotopography via PDMS NPs can be an effective strategy for emulating the native cellular functions of keratinocytes on PDMS based cell culture devices.

Chiral nanomaterials in tissue engineering

Addressing significant medical challenges arising from tissue damage and organ failure, the field of tissue engineering has evolved to provide revolutionary approaches for regenerating functional tissues and organs. This involves employing various techniques, including the development and application of novel nanomaterials. Among them, chiral nanomaterials comprising non-superimposable nanostructures with their mirror images have recently emerged as innovative biomaterial candidates to guide tissue regeneration due to their unique characteristics. Chiral nanomaterials including chiral fibre supramolecular hydrogels, polymer-based chiral materials, self-assembling peptides, chiral-patterned surfaces, and the recently developed intrinsically chiroptical nanoparticles have demonstrated remarkable ability to regulate biological processes through routes such as enantioselective catalysis and enhanced antibacterial activity. Despite several recent reviews on chiral nanomaterials, limited attention has been given to the specific potential of these materials in facilitating tissue regeneration processes. Thus, this timely review aims to fill this gap by exploring the fundamental characteristics of chiral nanomaterials, including their chiroptical activities and analytical techniques. Also, the recent advancements in incorporating these materials in tissue engineering applications are highlighted. The review concludes by critically discussing the outlook of utilizing chiral nanomaterials in guiding future strategies for tissue engineering design.

Resorbable conductive materials for optimally interfacing medical devices with the living

Implantable and wearable bioelectronic systems are arising growing interest in the medical field. Linking the microelectronic (electronic conductivity) and biological (ionic conductivity) worlds, the biocompatible conductive materials at the electrode/tissue interface are key components in these systems. We herein focus more particularly on resorbable bioelectronic systems, which can safely degrade in the biological environment once they have completed their purpose, namely, stimulating or sensing biological activity in the tissues. Resorbable conductive materials are also explored in the fields of tissue engineering and 3D cell culture. After a short description of polymer-based substrates and scaffolds, and resorbable electrical conductors, we review how they can be combined to design resorbable conductive materials. Although these materials are still emerging, various medical and biomedical applications are already taking shape that can profoundly modify post-operative and wound healing follow-up. Future challenges and perspectives in the field are proposed.

Nel-like Molecule Type 1 Combined with Gold Nanoparticles Modulates Macrophage Polarization, Osteoclastogenesis, and Oral Microbiota in Periodontitis

The disruption of host-microbe homeostasis and uncontrolled inflammatory response have been considered as vital causes for developing periodontitis, subsequently leading to an imbalance between the bone and immune system and the collapse of bone homeostasis. Consequently, strategies to modulate the immune response and bone metabolization have become a promising approach to prevent and treat periodontitis. In this study, we investigated the cooperative effects of Nel-like molecule type 1 (Nell-1) and gold nanoparticles (AuNPs) on macrophage polarization, osteoclast differentiation, and the corresponding functions in an experimental model of periodontitis in rats. Nell-1-combined AuNPs in in vitro studies were found to reduce the production of inflammatory factors (TNF-α, p < 0.0001; IL-6, p = 0.0012), modulate the ratio of M2/M1 macrophages by inducing macrophage polarization into the M2 phenotype, and inhibit cell fusion, maturation, and activity of osteoclasts. Furthermore, the local application of Nell-1-combined AuNPs in in vivo studies resulted in alleviation of damages to the periodontal and bone tissues, modulation of macrophage polarization and the activity of osteoclasts, and alteration of the periodontal microbiota, in which the relative abundance of the probiotic Bifidobacterium increased (p < 0.05). These findings reveal that Nell-1-combined AuNPs could be a promising drug candidate for the prevention and treatment of periodontitis. However, Nell-1-combined AuNPs did not show organ toxicity or impair the integrity of intestinal epithelium but alter the gut microbiota, leading to the dysbiosis of gut microbiota. The adverse impact of changes in gut microbiota needs to be further investigated. Nonetheless, this study provides a novel perspective and direction for the biological safety assessment of biomaterials in oral clinical applications.

Improving the development of human engineered cardiac tissue by gold nanorods embedded extracellular matrix for long-term viability

A myocardial infarction (MI), commonly called a heart attack, results in the death of cardiomyocytes (CMs) in the heart. Tissue engineering provides a promising strategy for the treatment of MI, but the maturation of human engineered cardiac tissue (hECT) still requires improvement. Conductive polymers and nanomaterials have been incorporated into the extracellular matrix to enhance the mechanical and electrical coupling between cardiac cells. Here we report a simple approach to incorporate gold nanorods (GNRs) into the fibrin hydrogel to form a GNR-fibrin matrix, which is used as the major component of the extracellular matrix for forming a 3D hECT construct suspended between two flexible posts. The hECTs made with GNR-fibrin hydrogel showed markers of maturation such as higher twitch force, synchronous beating activity, sarcomere maturation and alignment, t-tubule network development, and calcium handling improvement. Most importantly, the GNR-hECTs can survive over 9 months. We envision that the hECT with GNRs holds the potential to restore the functionality of the infarcted heart.

Nanomaterials-combined methacrylated gelatin hydrogels (GelMA) for cardiac tissue constructs

Among non-communicable diseases, cardiovascular diseases are the most prevalent, accounting for approximately 17 million deaths per year. Despite conventional treatment, cardiac tissue engineering emerges as a potential alternative for the advancement and treatment of these patients, using biomaterials to replace or repair cardiac tissues. Among these materials, gelatin in its methacrylated form (GelMA) is a biodegradable and biocompatible polymer with adjustable biophysical properties. Furthermore, gelatin has the ability to replace and perform collagen-like functions for cell development in vitro. The interest in using GelMA hydrogels combined with nanomaterials is increasingly growing to promote the responsiveness to external stimuli and improve certain properties of these hydrogels by exploring the incorporation of nanomaterials into these hydrogels to serve as electrical signaling conductive elements. This review highlights the applications of electrically conductive nanomaterials associated with GelMA hydrogels for the development of structures for cardiac tissue engineering, by focusing on studies that report the combination of GelMA with nanomaterials, such as gold and carbon derivatives (carbon nanotubes and graphene), in addition to the possibility of applying these materials in 3D tissue engineering, developing new possibilities for cardiac studies.

Biomolecules based hydrogels and their potential biomedical applications: A comprehensive review

The need for biocompatible drug carriers has been significantly increased from the past few years. Researchers show great interest in the development of more versatile and sophisticated biomaterials based drug carriers. Hydrogels are beneficial drug carriers and easily release the controlled amount of drug at target site due to its tunable structure. The hydrogels made-up of potent biological macromolecules including collagen, gelatin, fibrin, elastin, fibroin, chitosan, starch, alginate, agarose and carrageenan have been proven as versatile biomaterials. These are three-dimensional polymeric networks, synthesized by crosslinking of hydrophilic polymers. The biological macromolecules based hydrogels containing therapeutic substances are used in a wide range of biomedical applications including wound healing, tissue engineering, cosmetics and contact lenses. However, many aspects related to hydrogels such as the mechanism of cross-linking and molecular entanglement are not clear. So, there is a need to do more research and exploration toward the extensive and cost-effective use of hydrogels. The present review article elaborately discusses the biomolecules based hydrogels and their possible biomedical applications in different fields.

Electrospun Nanofiber Scaffolds Loaded with Metal-Based Nanoparticles for Wound Healing

Failures of wound healing have been a focus of research worldwide. With the continuous development of materials science, electrospun nanofiber scaffolds loaded with metal-based nanoparticles provide new ideas and methods for research into new tissue engineering materials due to their excellent antibacterial, anti-inflammatory, and wound healing abilities. In this review, the stages of extracellular matrix and wound healing, electrospun nanofiber scaffolds, metal-based nanoparticles, and metal-based nanoparticles supported by electrospun nanofiber scaffolds are reviewed, and their characteristics and applications are introduced. We discuss in detail the current research on wound healing of metal-based nanoparticles and electrospun nanofiber scaffolds loaded with metal-based nanoparticles, and we highlight the potential mechanisms and promising applications of these scaffolds for promoting wound healing.

Nanomaterials for small diameter vascular grafts: overview and outlook

Small-diameter vascular grafts (SDVGs) cannot meet current clinical demands owing to their suboptimal long-term patency rate. Various materials have been employed to address this issue, including nanomaterials (NMs), which have demonstrated exceptional capabilities and promising application potentials. In this review, the utilization of NMs in different forms, including nanoparticles, nanofibers, and nanofilms, in the SDVG field is discussed, and future perspectives for the development of NM-loading SDVGs are highlighted. It is expected that this review will provide helpful information to scholars in the innovative interdiscipline of cardiovascular disease treatment and NM.

Leveraging 3D Bioprinting and Photon-Counting Computed Tomography to Enable Noninvasive Quantitative Tracking of Multifunctional Tissue Engineered Constructs

3D bioprinting is revolutionizing the fields of personalized and precision medicine by enabling the manufacturing of bioartificial implants that recapitulate the structural and functional characteristics of native tissues. However, the lack of quantitative and noninvasive techniques to longitudinally track the function of implants has hampered clinical applications of bioprinted scaffolds. In this study, multimaterial 3D bioprinting, engineered nanoparticles (NPs), and spectral photon-counting computed tomography (PCCT) technologies are integrated for the aim of developing a new precision medicine approach to custom-engineer scaffolds with traceability. Multiple CT-visible hydrogel-based bioinks, containing distinct molecular (iodine and gadolinium) and NP (iodine-loaded liposome, gold, methacrylated gold (AuMA), and Gd2 O3 ) contrast agents, are used to bioprint scaffolds with varying geometries at adequate fidelity levels. In vitro release studies, together with printing fidelity, mechanical, and biocompatibility tests identified AuMA and Gd2 O3 NPs as optimal reagents to track bioprinted constructs. Spectral PCCT imaging of scaffolds in vitro and subcutaneous implants in mice enabled noninvasive material discrimination and contrast agent quantification. Together, these results establish a novel theranostic platform with high precision, tunability, throughput, and reproducibility and open new prospects for a broad range of applications in the field of precision and personalized regenerative medicine.

Fully Integrated Point-of-Care Platform for the Self-Monitoring of Phenylalanine in Finger-Prick Blood

Development of point-of-care platforms combining reliability and ease of use is a challenge for the evolution of sensing in healthcare technologies. Here, we report the development and testing of a fully integrated enzymatic colorimetric assay for the sensing of phenylalanine in blood samples from phenylketonuria patients. The platform works with a customized mobile app for data acquisition and visualization and comprises an electronic system and a disposable sensor. The sensing approach is based on specific enzymatic phenylalanine recognition, and the optical transduction method is based on in situ gold nanostructure formation. The phenylketonuria (PKU) smart sensor platform is conceived to perform self-monitoring on phenylalanine levels and real-time therapy tuning, thanks to the direct connection with clinicians. Validation of the technologies with a population of patients affected by PKU, together with the concurrent validation of the platform through centralized laboratories, has confirmed the good analytical performances in terms of sensitivity and specificity, robustness, and utility for phenylalanine sensing. The self-monitoring of phenylalanine for the daily identification of abnormal health conditions could facilitate rapid therapy tuning, improving the wellness of PKU patients.

Theoretical study of the saturation and nature of the hydrogen bonds to gold

Traditional hydrogen bonds are well-known to exhibit directionality and saturation. By contrast, gold involved hydrogen bonds (GHBs) have been extensively studied but remain lack of in-depth understanding towards the intrinsic nature and saturation property. This work exemplifies three series of complexes: [L-Au-L]-⋯(HF)n (L = H, CH3, (CH3)3; n = 1-8) containing GHBs to dig into the intrinsic nature with the aid of multiple theoretical analysis methods, finding that the formation of GHB is highly subject to orbital interactions along with steric hindrance. Moreover, the saturation level of GHBs largely depends on the ligand attached to the gold center, since different ligands typically possess varying electron-giving ability and steric volume. This work confirms the coexistence of as many as 6 GHBs for one Au atom and thoroughly studies the saturation level of GHBs, which will provide new insights into GHBs and facilitate future synthesis of more complicated gold complexes.

Recent advances in nano-scaffolds for tissue engineering applications: Toward natural therapeutics

Among the promising methods for repairing or replacing tissue defects in the human body and the hottest research topics in medical science today are regenerative medicine and tissue engineering. On the other hand, nanotechnology has been expanded into different areas of regenerative medicine and tissue engineering due to its essential benefits in improving performance in various fields. Nanotechnology, a helpful strategy in tissue engineering, offers new solutions to unsolved problems. Especially considering the excellent physicochemical properties of nanoscale structures, their application in regenerative medicine has been gradually developed, and a lot of research has been conducted in this field. In this regard, various nanoscale structures, including nanofibers, nanosheets, nanofilms, nano-clays, hollow spheres, and different nanoparticles, have been developed to advance nanotechnology strategies with tissue repair goals. Here, we comprehensively review the application of the mentioned nanostructures in constructing nanocomposite scaffolds for regenerative medicine and tissue engineering. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement Diagnostic Tools > Biosensing.

Cardiac regeneration - Past advancements, current challenges, and future directions

Cardiovascular disease is the leading cause of mortality and morbidity worldwide. Despite improvements in the standard of care for patients with heart diseases, including innovation in pharmacotherapy and surgical interventions, none have yet been proven effective to prevent the progression to heart failure. Cardiac transplantation is the last resort for patients with severe heart failure, but donor shortages remain a roadblock. Cardiac regenerative strategies include cell-based therapeutics, gene therapy, direct reprogramming of non-cardiac cells, acellular biologics, and tissue engineering methods to restore damaged hearts. Significant advancements have been made over the past several decades within each of these fields. This review focuses on the advancements of: 1) cell-based cardiac regenerative therapies, 2) the use of noncoding RNA to induce endogenous cell proliferation, and 3) application of bioengineering methods to promote retention and integration of engrafted cells. Different cell sources have been investigated, including adult stem cells derived from bone marrow and adipose cells, cardiosphere-derived cells, skeletal myoblasts, and pluripotent stem cells. In addition to cell-based transplantation approaches, there have been accumulating interest over the past decade in inducing endogenous CM proliferation for heart regeneration, particularly with the use of noncoding RNAs such as miRNAs and lncRNAs. Bioengineering applications have focused on combining cell-transplantation approaches with fabrication of a porous, vascularized scaffold using biomaterials and advanced bio-fabrication techniques that may offer enhanced retention of transplanted cells, with the hope that these cells would better engraft with host tissue to improve cardiac function. This review summarizes the present status and future challenges of cardiac regenerative therapies.

A Platform for Assessing Cellular Contractile Function Based on Magnetic Manipulation of Magnetoresponsive Hydrogel Films

Despite significant advancements in in vitro cardiac modeling approaches, researchers still lack the capacity to obtain in vitro measurements of a key indicator of cardiac function: contractility, or stroke volume under specific loading conditions-defined as the pressures to which the heart is subjected prior to and during contraction. This work puts forward a platform that creates this capability, by providing a means of dynamically controlling loading conditions in vitro. This dynamic tissue loading platform consists of a thin magnetoresponsive hydrogel cantilever on which 2D engineered myocardial tissue is cultured. Exposing the cantilever to an external magnetic field-generated by positioning magnets at a controlled distance from the cantilever-causes the hydrogel film to stretch, creating tissue load. Next, cell contraction is induced through electrical stimulation, and the force of the contraction is recorded, by measuring the cantilever's deflection. Force-length-based measurements of contractility are then derived, comparable to clinical measurements. In an illustrative application, the platform is used to measure contractility both in untreated myocardial tissue and in tissue exposed to an inotropic agent. Clear differences are observed between conditions, suggesting that the proposed platform has significant potential to provide clinically relevant measurements of contractility.

A Review of Metal Nanoparticles Embedded in Hydrogel Scaffolds for Wound Healing In Vivo

An evolving field, nanotechnology has made its mark in the fields of nanoscience, nanoparticles, nanomaterials, and nanomedicine. Specifically, metal nanoparticles have garnered attention for their diverse use and applicability to dressings for wound healing due to their antimicrobial properties. Given their convenient integration into wound dressings, there has been increasing focus dedicated to investigating the physical, mechanical, and biological characteristics of these nanoparticles as well as their incorporation into biocomposite materials, such as hydrogel scaffolds for use in lieu of antibiotics as well as to accelerate and ameliorate healing. Though rigorously tested and applied in both medical and non-medical applications, further investigations have not been carried out to bring metal nanoparticle-hydrogel composites into clinical practice. In this review, we provide an up-to-date, comprehensive review of advancements in the field, with emphasis on implications on wound healing in in vivo experiments.

Temperature-Derived Purification of Gold Nano-Bipyramids for Colorimetric Detection of Tannic Acid

Gold nanostructures have attracted broad attention. Among various nanostructures, gold nanobipyramids have shown great potential in sensing, biomedicine, environmental protection, chemical catalysis, and optics due to their unique physical and optical properties and ease of chemical functionalization. Compared with other plasmonic nanostructures, gold nanobipyramids possess narrow optical resonances, stronger plasmonic local field enhancement, and size- and shape-dependent surface plasmon resonance. However, the synthesis and purification of homogeneous gold nanobipyramids are very challenging. The gold nanobipyramids synthesized via the commonly used seed-mediated growth method have low yields and are often coproduced with spherical nanoparticles. In this study, we reported a temperature-derived purification method for the isolation of gold bipyramids. In the presence of salt, by altering the temperature of the solution, large gold bipyramids can be separated from small spherical nanoparticles. As a result, a yield of as high as 97% gold nanobipyramids can be achieved through a single round of purification, and correspondingly, the ratio between the longitudinal surface plasmon resonance (LSPR) and transverse SPR intensity significantly increases to as high as 6.7. The purified gold nanobipyramids can be used as a colorimetric probe in the detection of tannic acid with a detection limit of 0.86 μM and a linear detection range from 1.25 to 37.5 μM.

Inorganic/organic combination: Inorganic particles/polymer composites for tissue engineering applications

Biomaterials have ushered the field of tissue engineering and regeneration into a new era with the development of advanced composites. Among these, the composites of inorganic materials with organic polymers present unique structural and biochemical properties equivalent to naturally occurring hybrid systems such as bones, and thus are highly desired. The last decade has witnessed a steady increase in research on such systems with the focus being on mimicking the peculiar properties of inorganic/organic combination composites in nature. In this review, we discuss the recent progress on the use of inorganic particle/polymer composites for tissue engineering and regenerative medicine. We have elaborated the advantages of inorganic particle/polymer composites over their organic particle-based composite counterparts. As the inorganic particles play a crucial role in defining the features and regenerative capacity of such composites, the review puts a special emphasis on the various types of inorganic particles used in inorganic particle/polymer composites. The inorganic particles that are covered in this review are categorised into two broad types (1) solid (e.g., calcium phosphate, hydroxyapatite, etc.) and (2) porous particles (e.g., mesoporous silica, porous silicon etc.), which are elaborated in detail with recent examples. The review also covers other new types of inorganic material (e.g., 2D inorganic materials, clays, etc.) based polymer composites for tissue engineering applications. Lastly, we provide our expert analysis and opinion of the field focusing on the limitations of the currently used inorganic/organic combination composites and the immense potential of new generation of composites that are in development.

Imageable AuNP-ECM Hydrogel Tissue Implants for Regenerative Medicine

In myocardial infarction, a blockage in one of the coronary arteries leads to ischemic conditions in the left ventricle of the myocardium and, therefore, to significant death of contractile cardiac cells. This process leads to the formation of scar tissue, which reduces heart functionality. Cardiac tissue engineering is an interdisciplinary technology that treats the injured myocardium and improves its functionality. However, in many cases, mainly when employing injectable hydrogels, the treatment may be partial because it does not fully cover the diseased area and, therefore, may not be effective and even cause conduction disorders. Here, we report a hybrid nanocomposite material composed of gold nanoparticles and an extracellular matrix-based hydrogel. Such a hybrid hydrogel could support cardiac cell growth and promote cardiac tissue assembly. After injection of the hybrid material into the diseased area of the heart, it could be efficiently imaged by magnetic resonance imaging (MRI). Furthermore, as the scar tissue could also be detected by MRI, a distinction between the diseased area and the treatment could be made, providing information about the ability of the hydrogel to cover the scar. We envision that such a nanocomposite hydrogel may improve the accuracy of tissue engineering treatment.

Theoretical Investigations on the Plasmon-Mediated Dissociation of Small Molecules in the Presence of Silver Atomic Wires

Plasmonic nanoparticles can promote bond activation in adsorbed molecules under relatively benign conditions via excitation of the nanoparticle's plasmon resonance. As the plasmon resonance often falls within the visible light region, plasmonic nanomaterials are a promising class of catalysts. However, the exact mechanisms through which plasmonic nanoparticles activate the bonds of nearby molecules are still unclear. Herein, we evaluate Ag₈-X₂ (X = N, H) model systems via real-time time-dependent density functional theory (RT-TDDFT), linear response time-dependent density functional theory (LR-TDDFT), and Ehrenfest dynamics in order to better understand the bond activation processes of N₂ and H₂ facilitated by the presence of the atomic silver wire under excitation at the plasmon resonance energies. We find that dissociation is possible for both small molecules at high electric field strength. Activation of each adsorbate is symmetry- and electric field-dependent, and H₂ activates at lower electric field strengths than N₂. This work serves as a step toward understanding the complex time-dependent electron and electron-nuclear dynamics between plasmonic nanowires and adsorbed small molecules.

Polycaprolactone-MXene Nanofibrous Scaffolds for Tissue Engineering

New conductive materials for tissue engineering are needed for the development of regenerative strategies for nervous, muscular, and heart tissues. Polycaprolactone (PCL) is used to obtain biocompatible and biodegradable nanofiber scaffolds by electrospinning. MXenes, a large class of biocompatible 2D nanomaterials, can make polymer scaffolds conductive and hydrophilic. However, an understanding of how their physical properties affect potential biomedical applications is still lacking. We immobilized Ti3C2Tx MXene in several layers on the electrospun PCL membranes and used positron annihilation analysis combined with other techniques to elucidate the defect structure and porosity of nanofiber scaffolds. The polymer base was characterized by the presence of nanopores. The MXene surface layers had abundant vacancies at temperatures of 305-355 K, and a voltage resonance at 8 × 104 Hz with the relaxation time of 6.5 × 106 s was found in the 20-355 K temperature interval. The appearance of a long-lived component of the positron lifetime was observed, which was dependent on the annealing temperature. The study of conductivity of the composite scaffolds in a wide temperature range, including its inductive and capacity components, showed the possibility of the use of MXene-coated PCL membranes as conductive biomaterials. The electronic structure of MXene and the defects formed in its layers were correlated with the biological properties of the scaffolds in vitro and in bacterial adhesion tests. Double and triple MXene coatings formed an appropriate environment for cell attachment and proliferation with mild antibacterial effects. A combination of structural, chemical, electrical, and biological properties of the PCL-MXene composite demonstrated its advantage over the existing conductive scaffolds for tissue engineering.

Electrically conductive carbon-based (bio)-nanomaterials for cardiac tissue engineering

A proper self-regenerating capability is lacking in human cardiac tissue which along with the alarming rate of deaths associated with cardiovascular disorders makes tissue engineering critical. Novel approaches are now being investigated in order to speedily overcome the challenges in this path. Tissue engineering has been revolutionized by the advent of nanomaterials, and later by the application of carbon-based nanomaterials because of their exceptional variable functionality, conductivity, and mechanical properties. Electrically conductive biomaterials used as cell bearers provide the tissue with an appropriate microenvironment for the specific seeded cells as substrates for the sake of protecting cells in biological media against attacking mechanisms. Nevertheless, their advantages and shortcoming in view of cellular behavior, toxicity, and targeted delivery depend on the tissue in which they are implanted or being used as a scaffold. This review seeks to address, summarize, classify, conceptualize, and discuss the use of carbon-based nanoparticles in cardiac tissue engineering emphasizing their conductivity. We considered electrical conductivity as a key affecting the regeneration of cells. Correspondingly, we reviewed conductive polymers used in tissue engineering and specifically in cardiac repair as key biomaterials with high efficiency. We comprehensively classified and discussed the advantages of using conductive biomaterials in cardiac tissue engineering. An overall review of the open literature on electroactive substrates including carbon-based biomaterials over the last decade was provided, tabulated, and thoroughly discussed. The most commonly used conductive substrates comprising graphene, graphene oxide, carbon nanotubes, and carbon nanofibers in cardiac repair were studied.

The Use of Metallic Nanoparticles in Wound Healing: New Perspectives

Chronic wounds represent a challenge for the health area, as they directly impact patients' quality of life and represent a threat to public health and the global economy due to their high cost of treatment. Alternative strategies must be developed for cost-effective and targeted treatment. In this scenario, the emerging field of nanobiotechnology may provide an alternative platform to develop new therapeutic agents for the chronic wound healing process. This manuscript aims to demonstrate that the application of metallic nanoparticles (gold, silver, copper, and zinc oxide) opened a new chapter in the treatment of wounds, as they have different properties such as drug delivery, antimicrobial activity, and healing acceleration. Furthermore, metallic nanoparticles (NPs) produced through green synthesis ensure less toxicity in biological tissues, and greater safety of applicability, other than adding the effects of NPs with those of extracts.

Effective treatment of intractable diseases using nanoparticles to interfere with vascular supply and angiogenic process

Angiogenesis is a vital biological process involving blood vessels forming from pre-existing vascular systems. This process contributes to various physiological activities, including embryonic development, hair growth, ovulation, menstruation, and the repair and regeneration of damaged tissue. On the other hand, it is essential in treating a wide range of pathological diseases, such as cardiovascular and ischemic diseases, rheumatoid arthritis, malignancies, ophthalmic and retinal diseases, and other chronic conditions. These diseases and disorders are frequently treated by regulating angiogenesis by utilizing a variety of pro-angiogenic or anti-angiogenic agents or molecules by stimulating or suppressing this complicated process, respectively. Nevertheless, many traditional angiogenic therapy techniques suffer from a lack of ability to achieve the intended therapeutic impact because of various constraints. These disadvantages include limited bioavailability, drug resistance, fast elimination, increased price, nonspecificity, and adverse effects. As a result, it is an excellent time for developing various pro- and anti-angiogenic substances that might circumvent the abovementioned restrictions, followed by their efficient use in treating disorders associated with angiogenesis. In recent years, significant progress has been made in different fields of medicine and biology, including therapeutic angiogenesis. Around the world, a multitude of research groups investigated several inorganic or organic nanoparticles (NPs) that had the potential to effectively modify the angiogenesis processes by either enhancing or suppressing the process. Many studies into the processes behind NP-mediated angiogenesis are well described. In this article, we also cover the application of NPs to encourage tissue vascularization as well as their angiogenic and anti-angiogenic effects in the treatment of several disorders, including bone regeneration, peripheral vascular disease, diabetic retinopathy, ischemic stroke, rheumatoid arthritis, post-ischemic cardiovascular injury, age-related macular degeneration, diabetic retinopathy, gene delivery-based angiogenic therapy, protein delivery-based angiogenic therapy, stem cell angiogenic therapy, and diabetic retinopathy, cancer that may benefit from the behavior of the nanostructures in the vascular system throughout the body. In addition, the accompanying difficulties and potential future applications of NPs in treating angiogenesis-related diseases and antiangiogenic therapies are discussed.

Biomaterial-assisted biotherapy: A brief review of biomaterials used in drug delivery, vaccine development, gene therapy, and stem cell therapy

Biotherapy has recently become a hotspot research topic with encouraging prospects in various fields due to a wide range of treatments applications, as demonstrated in preclinical and clinical studies. However, the broad applications of biotherapy have been limited by critical challenges, including the lack of safe and efficient delivery systems and serious side effects. Due to the unique potentials of biomaterials, such as good biocompatibility and bioactive properties, biomaterial-assisted biotherapy has been demonstrated to be an attractive strategy. The biomaterial-based delivery systems possess sufficient packaging capacity and versatile functions, enabling a sustained and localized release of drugs at the target sites. Furthermore, the biomaterials can provide a niche with specific extracellular conditions for the proliferation, differentiation, attachment, and migration of stem cells, leading to tissue regeneration. In this review, the state-of-the-art studies on the applications of biomaterials in biotherapy, including drug delivery, vaccine development, gene therapy, and stem cell therapy, have been summarized. The challenges and an outlook of biomaterial-assisted biotherapies have also been discussed.

Synthesis and stability of switchable CO2-responsive foaming coupled with nanoparticles

CO₂-responsive foaming has been drawing huge attention due to its unique switching characteristics in academic research and industrial practices, whereas its stability remains questionable for further applications. In this paper, a new CO₂-switchable foam was synthesized by adding the preferably selected hydrophilic nanoparticle N20 into the foaming agent C₁₂A, through a series of analytical experiments. Overall, the synergy between cationic surfactants and nanoparticles with a contact angle of 37.83° is the best. More specifically, after adding 1.5 wt% N20, the half-life of foam is 14 times longer than that of pure C₁₂A foam. What’s more, the C₁₂A-N20 solution is validated to own distinctive CO₂-N₂ switching features because very slight foaming degradations are observed in terms of the foaming volume and half-life time even after three cycles of CO₂-N₂ injections. This study is of paramount importance pertaining to future CO₂ foam research and applications in energy and environmental practices.

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Cationic surfactants have the best synergy with NPs with a contact angle of 37.83°

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The foam stability increased with the increase of NPs concentration

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CO₂/N₂ can control the foaming properties of C₁₂A-N20 solution and are reversible

New Green Approaches in Nanoparticles Synthesis: An Overview

Nanotechnology is constantly expanding, with nanomaterials being more and more used in common commercial products that define our modern life. Among all types of nanomaterials, nanoparticles (NPs) occupy an important place, considering the great amount that is produced nowadays and the diversity of their applications. Conventional techniques applied to synthesize NPs have some issues that impede them from being appreciated as safe for the environment and health. The alternative to these might be the use of living organisms or biological extracts that can be involved in the green approach synthesis of NPs, a process that is free of harmful chemicals, cost-effective and a low energy consumer. Several factors, including biological reducing agent concentration, initial precursor salt concentration, agitation, reaction time, pH, temperature and light, can influence the characteristics of biologically synthesized NPs. The interdependence between these reaction parameters was not explored, being the main impediment in the implementation of the biological method on an industrial scale. Our aim is to present a brief review that focuses on the current knowledge regarding how the aforementioned factors can control the size and shape of green-synthesized NPs. We also provide an overview of the biomolecules that were found to be suitable for NP synthesis. This work is meant to be a support for researchers who intend to develop new green approaches for the synthesis of NPs.

Conductive and Semiconductive Nanocomposite-Based Hydrogels for Cardiac Tissue Engineering

Cardiovascular disease is the leading cause of death worldwide and the most common cause is myocardial infarction. Therefore, appropriate approaches should be used to repair damaged heart tissue. Recently, cardiac tissue engineering approaches have been extensively studied. Since the creation of the nature of cardiovascular tissue engineering, many advances have been made in cellular and scaffolding technologies. Due to the hydrated and porous structures of the hydrogel, they are used as a support matrix to deliver cells to the infarct tissue. In heart tissue regeneration, bioactive and biodegradable hydrogels are required by simulating native tissue microenvironments to support myocardial wall stress in addition to preserving cells. Recently, the use of nanostructured hydrogels has increased the use of nanocomposite hydrogels and has revolutionized the field of cardiac tissue engineering. Therefore, to overcome the limitation of the use of hydrogels due to their mechanical fragility, various nanoparticles of polymers, metal, and carbon are used in tissue engineering and create a new opportunity to provide hydrogels with excellent properties. Here, the types of synthetic and natural polymer hydrogels, nanocarbon-based hydrogels, and other nanoparticle-based materials used for cardiac tissue engineering with emphasis on conductive nanostructured hydrogels are briefly introduced.

Turning gray selenium into a nanoaccelerator of tissue regeneration by PEG modification

Selenium (Se) is an essential trace element involved in nearly all human physiological processes but suffers from a narrow margin between benefit and toxicity. The nanoform of selenium has been proven shown to be more bioavailable and less toxic, yet significant challenges remain regarding the efficient and feasible synthesis of biologically active nanoselenium. In addition, although nanoselenium has shown a variety of biological activities, more interesting nanoselenium features are expected. In this work, hydrosoluble nanoselenium termed Nano-Se in the zero oxidation state was synthesized between gray Se and PEG. A zebrafish screen was carried out in zebrafish larvae cocultured with Nano-Se. Excitingly, Nano-Se promoted the action of the FGFR, Wnt, and VEGF signaling pathways, which play crucial roles in tissue regeneration. As expected, Nano-Se not only achieved the regeneration of zebrafish tail fins and mouse skin but also promoted the repair of skin in diabetic mice while maintaining a profitable safe profile. In brief, the Nano-Se reported here provided an efficient and feasible method for bioactive nanoselenium synthesis and not only expanded the application of nanoselenium to regenerative medicine but also likely reinvigorated efforts for discovering more peculiarunique biofunctions of nanoselenium in a great variety of human diseases.

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It was found that selenium nanoparticles through FGFR、Wnt、VEGFR signal pathway to promote tissue regeneration;

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Development a new water-soluble, bio-compatible, zero oxidation state Nano-Se;

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Development a new efficient and safe nano-biologic agent for promoting tissue regeneration.

Advancing Engineered Heart Muscle Tissue Complexity with Hydrogel Composites

A heart attack results in the permanent loss of heart muscle and can lead to heart disease, which kills more than 7 million people worldwide each year. To date, outside of heart transplantation, current clinical treatments cannot regenerate lost heart muscle or restore full function to the damaged heart. There is a critical need to create engineered heart tissues with structural complexity and functional capacity needed to replace damaged heart muscle. The inextricable link between structure and function suggests that hydrogel composites hold tremendous promise as a biomaterial-guided strategy to advance heart muscle tissue engineering. Such composites provide biophysical cues and functionality as a provisional extracellular matrix that hydrogels cannot on their own. This review describes the latest advances in the characterization of these biomaterial systems and using them for heart muscle tissue engineering. The review integrates results across the field to provide new insights on critical features within hydrogel composites and perspectives on the next steps to harnessing these promising biomaterials to faithfully reproduce the complex structure and function of native heart muscle.

Gold nanoparticles targeting the autophagy-lysosome system to combat the inflammation-compromised osteogenic potential of periodontal ligament stem cells: From mechanism to therapy

Although substantial data indicate that the osteogenic potential of periodontal ligament stem cells (PDLSCs) is compromised under inflammatory conditions, the underlying mechanism remains largely unexplored. In this study, we found that both the autophagy levels and autophagic flux levels were decreased in PDLSCs incubated under inflammatory conditions (I-PDLSCs). Based on the increased expression of LC3 II (at an autophagy level) and decreased accumulation of LC3 II (at an autophagic flux level) in I-PDLSCs, we speculated that the disruption of I-PDLSC autophagy arose from dysfunction of the cellular autophagy-lysosome system. Subsequently, our hypothesis was demonstrated by inhibited autophagosome-lysosome fusion, damaged lysosomal function, and suppressed activation of transcription factor EB (TFEB, a master regulator of the autophagy-lysosome system) in I-PDLSCs and verified by TFEB overexpression in I-PDLSCs. We found that gold nanoparticle (Au NP) treatment rescued the osteogenic potential of I-PDLSCs by restoring the inflammation-compromised autophagy-lysosome system. In this context, Au NP ceased to be effective when TFEB was knocked down in PDLSCs. Our data demonstrate the crucial role of the autophagy-lysosome system in cellular osteogenesis under inflammatory conditions and suggest a new target for rescuing inflammation-induced cell dysfunction using nanomaterials to aid cell biology and tissue regeneration.