Facile Size Tunable Skin-Adaptive Patch for Accelerating Wound Healing.

Owing to the moist and curved interfaces of skin wounds, enhancing the adhesiveness while maintaining delivery efficacy of biomolecules has drawn significant attention in advanced wound dressings. Despite tremendous trials to load biomolecules with sound adhesiveness, the complicated fabricating processes and abnormal allergic responses that are attributed to chemical moiety-based adhesives remain as major problems. To this end, in this study a one-step fabrication process is developed to manufacture microstructures with both a therapeutic (cylindrical structure for embossed structure human adipose-derived stem cell sheet, ESS) and an adhesive part (octopi-inspired structure of adhesive, OIA), which ESOIA is called. OIA showed the highest adhesion strength in both dry (1.48 N cm-2) and wet pig skin conditions (0.81 N cm-2), maintaining the adhesive properties after repeated attach-detach trials. ESS from the therapeutic part of ESOIA also showed an enhanced angiogenic effect compared with the ones that are normally cultured in vitro. ESS also showed improved in vivo wound healing outcomes following enhanced cell engraftment compared to the cell injection group by means of intact cell-extracellular matrix interactions.

Photocuring 3D printing technology as an advanced tool for promoting angiogenesis in hypoxia-related diseases.

Three-dimensional (3D) bioprinting has emerged as a promising strategy for fabricating complex tissue analogs with intricate architectures, such as vascular networks. Achieving this necessitates bioink formulations that possess highly printable properties and provide a cell-friendly microenvironment mimicking the native extracellular matrix. Rapid advancements in printing techniques continue to expand the capabilities of researchers, enabling them to overcome existing biological barriers. This review offers a comprehensive examination of ultraviolet-based 3D bioprinting, renowned for its exceptional precision compared to other techniques, and explores its applications in inducing angiogenesis across diverse tissue models related to hypoxia. The high-precision and rapid photocuring capabilities of 3D bioprinting are essential for accurately replicating the intricate complexity of vascular networks and extending the diffusion limits for nutrients and gases. Addressing the lack of vascular structure is crucial in hypoxia-related diseases, as it can significantly improve oxygen delivery and overall tissue health. Consequently, high-resolution 3D bioprinting facilitates the creation of vascular structures within three-dimensional engineered tissues, offering a potential solution for addressing hypoxia-related diseases. Emphasis is placed on fundamental components essential for successful 3D bioprinting, including cell types, bioink compositions, and growth factors highlighted in recent studies. The insights provided in this review underscore the promising prospects of leveraging 3D printing technologies for addressing hypoxia-related diseases through the stimulation of angiogenesis, complementing the therapeutic efficacy of cell therapy.

A biospecies-derived genomic DNA hybrid gel electrolyte for electrochemical energy storage.

Intrinsic impediments, namely weak mechanical strength, low ionic conductivity, low electrochemical performance, and stability have largely inhibited beyond practical applications of hydrogels in electronic devices and remains as a significant challenge in the scientific world. Here, we report a biospecies-derived genomic DNA hybrid gel electrolyte with many synergistic effects, including robust mechanical properties (mechanical strength and elongation of 6.98 MPa and 997.42%, respectively) and ion migration channels, which consequently demonstrated high ionic conductivity (73.27 mS/cm) and superior electrochemical stability (1.64 V). Notably, when applied to a supercapacitor the hybrid gel-based devices exhibit a specific capacitance of 425 F/g. Furthermore, it maintained rapid charging/discharging with a capacitance retention rate of 93.8% after ∼200,000 cycles while exhibiting a maximum energy density of 35.07 Wh/kg and a maximum power density of 193.9 kW/kg. This represents the best value among the current supercapacitors and can be immediately applied to minicars, solar cells, and LED lightning. The widespread use of DNA gel electrolytes will revolutionize human efforts to industrialize high-performance green energy.

Analysis of current technology status for the industrialization of cultured meat.

Cultured meat is expected to become an important material for future food production; however, contrary to initial expectations, the full-scale industrialization of cultured meat is slow and the actual level and opened technology amount is very limited. This study reviews the publicly available technologies of cultured meat and suggests future developmental directions and research agenda. As a result of analyzing papers, patents, and press releases published over the past 10 years, it was found that cultured meat production technology is still at the prototype production level. This is because most papers published are about culture medium and scaffold development, culture conditions, and there is almost no research on finished cultured meat products. Worldwide, most of the filed patents are for producing cultured meat principles; most of them do not use food-grade materials and are not economically feasible for industrialization. Therefore, future research on the industrialization of cultured meat should focus on effective acquisition technologies for satellite cells; cell lineage and undifferentiated state maintenance technologies; the development of serum-free media and culture devices; the prevention of genetic modification, safety verification, and mass production. Furthermore, basic research on mechanisms and influencing factors related to cultured meat production is warranted.

Transplantation of Stem Cell Spheroid-Laden 3-Dimensional Patches with Bioadhesives for the Treatment of Myocardial Infarction.

Myocardial infarction (MI) is treated with stem cell transplantation using various biomaterials and methods, such as stem cell/spheroid injections, cell sheets, and cardiac patches. However, current treatment methods have some limitations, including low stem cell engraftment and poor therapeutic effects. Furthermore, these methods cause secondary damage to heart due to injection and suturing to immobilize them in the heart, inducing side effects. In this study, we developed stem cell spheroid-laden 3-dimensional (3D) patches (S_3DP) with biosealant to treat MI. This 3D patch has dual modules, such as open pockets to directly deliver the spheroids with their paracrine effects and closed pockets to improve the engraft rate by protecting the spheroid from harsh microenvironments. The spheroids formed within S_3DP showed increased viability and expression of angiogenic factors compared to 2-dimensional cultured cells. We also fabricated gelatin-based tissue adhesive biosealants via a thiol-ene reaction and disulfide bond formation. This biosealant showed stronger tissue adhesiveness than commercial fibrin glue. Furthermore, we successfully applied S_3DP using a biosealant in a rat MI model without suturing in vivo, thereby improving cardiac function and reducing heart fibrosis. In summary, S_3DP and biosealant have excellent potential as advanced stem cell therapies with a sutureless approach to MI treatment.

Fibroblast function recovery through rejuvenation effect of nanovesicles extracted from human adipose-derived stem cells irradiated with red light.

Fibroblasts (hDFs) are widely employed for skin regeneration and the treatment of various skin disorders, yet research were rarely investigated about restoration of diminished therapeutic efficacy due to cell senescence. The application of stem cell and stem cell-derived materials, exosomes, were drawn attention for the restoration functionality of fibroblasts, but still have limitation for unintended side effect or low yield. To advance, stem cell-derived nanovesicle (NV) have developed for effective therapeutic reagents with high yield and low risk. In this study, we have developed a method using red light irradiated human adipose-derived stem cells (hADSCs) derived NV (R-NVs) for enhancing the therapeutic efficacy and rejuvenating hDFs. Through red light irradiation, we were able to significantly increase the content of stemness factors and angiogenic biomolecules in R-NVs. Treatment with these R-NVs was found to enhance the migration ability and leading to rejuvenation of old hDFs to levels similar to those of young hDFs. In subsequent in vivo experiments, the treatment of old hDFs with R-NVs demonstrated a superior skin wound healing effect, surpassing that of young hDFs. In summary, this study successfully induced rejuvenation and leading to increased therapeutic efficacy to R-NVs treated old hDFs previously considered as biowaste.

Enhancing viability and angiogenic efficacy of mesenchymal stem cells via HSP90α and HSP27 regulation based on ROS stimulation for wound healing.

Light-based therapy has been reported as a potential preconditioning strategy to induce intracellular reactive oxygen species (ROS) signaling and improve the angiogenic properties of various types of cells. However, bio-stimulation mechanisms of light therapy in terms of ROS-heat shock proteins (HSPs) mediated anti-apoptotic and angiogenic pathways in human adult stem cells have not been fully delineated yet. Commonly used light sources such as light-emitting diode (LED) and laser are accompanied by drawbacks, such as phototoxicity, thermal damage, and excessive ROS induction, so the role and clinical implications of light-induced HSPs need to be investigated using a heat-independent light source. Here, we introduced organic LED (OLED) at 610 nm wavelength as a new light source to prevent thermal effects from interfering with the expression of HSPs. Our results showed that light therapy using OLED significantly upregulated anti-apoptotic and angiogenic factors in human bone marrow mesenchymal stem cells (hMSCs) at both gene and protein levels via the activation of HSP90α and HSP27, which were stimulated by ROS. In a mouse wound-closing model, rapid recovery and improved re-epithelization were observed in the light-treated hMSCs transplant group. This study demonstrates that the upregulation of Akt (protein kinase B)-nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling, caused by HSP90α and HSP27 expression, is the mechanism behind the anti-apoptotic and angiogenic effects of OLED treatment on stem cells.

Various Three-Dimensional Culture Methods and Cell Types for Exosome Production.

Cell-based therapies have been used as promising treatments for several untreatable diseases. However, cell-based therapies have side effects such as tumorigenesis and immune responses. To overcome these side effects, therapeutic effects of exosomes have been researched as replacements for cell-based therapies. In addition, exosomes reduced the risk that can be induced by cell-based therapies. Exosomes contain biomolecules such as proteins, lipids, and nucleic acids that play an essential role in cell-cell and cell-matrix interactions during biological processes. Since the introduction of exosomes, those have been proven perpetually as one of the most effective and therapeutic methods for incurable diseases. Much research has been conducted to enhance the properties of exosomes, including immune regulation, tissue repair, and regeneration. However, yield rate of exosomes is the critical obstacle that should be overcome for practical cell-free therapy. Three-dimensional (3D) culture methods are introduced as a breakthrough to get higher production yields of exosomes. For example, hanging drop and microwell were well known 3D culture methods and easy to use without invasiveness. However, these methods have limitation in mass production of exosomes. Therefore, a scaffold, spinner flask, and fiber bioreactor were introduced for mass production of exosomes isolated from various cell types. Furthermore, exosomes treatments derived from 3D cultured cells showed enhanced cell proliferation, angiogenesis, and immunosuppressive properties. This review provides therapeutic applications of exosomes using 3D culture methods.

Subaqueous 3D stem cell spheroid levitation culture using anti-gravity bioreactor based on sound wave superposition.

BACKGROUND: Recently, various studies have revealed that 3D cell spheroids have several advantages over 2D cells in stem cell culture. However, conventional 3D spheroid culture methods have some disadvantages and limitations such as time required for spheroid formation and complexity of the experimental process. Here, we used acoustic levitation as cell culture platform to overcome the limitation of conventional 3D culture methods. METHODS: In our anti-gravity bioreactor, continuous standing sonic waves created pressure field for 3D culture of human mesenchymal stem cells (hMSCs). hMSCs were trapped and aggerated in pressure field and consequently formed spheroids. The structure, viability, gene and protein expression of spheroids formed in the anti-gravity bioreactor were analyzed by electron microscope, immunostaining, polymerase chain reaction, and western blot. We injected hMSC spheroids fabricated by anti-gravity bioreactor into the mouse hindlimb ischemia model. Limb salvage was quantified to evaluate therapeutic efficacy of hMSC spheroids. RESULTS: The acoustic levitation in anti-gravity bioreactor made spheroids faster and more compact compared to the conventional hanging drop method, which resulted in the upregulation of angiogenic paracrine factors of hMSCs, such as vascular endothelial growth factor and angiopoietin 2. Injected hMSCs spheroids cultured in the anti-gravity bioreactor exhibited improved therapeutic efficacy, including the degree of limb salvage, capillary formation, and attenuation of fibrosis and inflammation, for mouse hindlimb ischemia model compared to spheroids formed by the conventional hanging drop method. CONCLUSION: Our stem cell culture system using acoustic levitation will be proposed as a new platform for the future 3D cell culture system.

Fortifying angiogenic efficacy of conditioned media using phototoxic-free blue light for wound healing.

We used a blue organic light-emitting diode (bOLED) to increase the paracrine factors secreted from human adipose-derived stem cells (hADSCs) for producing conditioned medium (CM). Our results showed that while the bOLED irradiation promotes a mild-dose reactive oxygen generation that enhances the angiogenic paracrine secretion of hADSCs, it does not induce phototoxicity. The bOLED enhances paracrine factors via a cell-signaling mechanism involving hypoxia-inducible factor 1 alpha. This study demonstrated that the CM resulting from bOLED treatment shows improved therapeutic effects on mouse wound-healing models. This method contributes to overcoming the barriers to stem-cell therapies, including the toxicity and low yields from other methods such as nanoparticles, synthetic polymers, and even cell-derived vesicles.

Suppressing cancer by damaging cancer cell DNA using LED irradiation.

BACKGROUND: High-energy irradiation eliminates cancer cells by destroying their genetic components. However, there are several side effects from doing this, such as fatigue, dermatitis, and hair loss, which remain obstacles to this treatment. Here, we propose a moderate method that uses low-energy white light from a light-emitting diode (LED) to selectively inhibit cancer cell proliferation without affecting normal cells. METHODS: The association between LED irradiation and cancer cell growth arrest was evaluated based on cell proliferation, viability, and apoptotic activity. Immunofluorescence, polymerase chain reaction, and western blotting were performed in vitro and in vivo to identify the metabolism related to the inhibition of HeLa cell proliferation. RESULTS: LED irradiation aggravated the defective p53 signaling pathway and induced cell growth arrest in cancer cells. Consequently, cancer cell apoptosis was induced by the increased DNA damage. Additionally, LED irradiation inhibited the proliferation of cancer cells by suppressing the MAPK pathway. Furthermore, the suppression of cancer growth by the regulation of p53 and MAPK was observed in cancer-bearing mice irradiated with LED. CONCLUSIONS: Our findings suggest that LED irradiation can suppress cancer cell activity and may contribute to preventing the proliferation of cancer cells after medical surgery without causing side effects.

Subaqueous free-standing 3D cell culture system for ultrafast cell compaction, mechano-inductive immune control, and improving therapeutic angiogenesis.

Conventional 3D cell culture methods require a comprehensive complement in labor-intensive and time-consuming processes along with in vivo circumstantial mimicking. Here, we describe a subaqueous free-standing 3D cell culture (FS) device that can induce the omnidirectional environment and generate ultrafast human adipose-derived stem cells (hADSCs) that efficiently aggregate with compaction using acoustic pressure. The cell culture conditions were optimized using the FS device and identified the underlying molecular mechanisms. Unique phenomena in cell aggregation have led to extraordinary cellular behavior that can upregulate cell compaction, mechanosensitive immune control, and therapeutic angiogenesis. Therefore, we designated the resulting cell aggregates as "pressuroid." Notably, external acoustic stimulation produced by the FS device affected the pressuroids. Furthermore, the pressuroids exhibited upregulation in mechanosensitive genes and proteins, PIEZO1/2. CyclinD1 and PCNA, which are strongly associated with cell adhesion and proliferation, were elevated by PIEZO1/2. In addition, we found that pressuroids significantly increase angiogenic paracrine factor secretion, promote cell adhesion molecule expression, and enhance M2 immune modulation of Thp1 cells. Altogether, we have concluded that our pressuroid would suggest a more effective therapy method for future cell therapy than the conventional one.

Fibronectin-Enriched Interface Using a Spheroid-Converged Cell Sheet for Effective Wound Healing.

Cell sheets and spheroids are cell aggregates with excellent tissue-healing effects. However, their therapeutic outcomes are limited by low cell-loading efficacy and low extracellular matrix (ECM). Preconditioning cells with light illumination has been widely accepted to enhance reactive oxygen species (ROS)-mediated ECM expression and angiogenic factor secretion. However, there are difficulties in controlling the amount of ROS required to induce therapeutic cell signaling. Here, we develop a microstructure (MS) patch that can culture a unique human mesenchymal stem cell complex (hMSCcx), spheroid-attached cell sheets. The spheroid-converged cell sheet structure of hMSCcx shows high ROS tolerance compared to hMSC cell sheets owing to its high antioxidant capacity. The therapeutic angiogenic efficacy of hMSCcx is reinforced by regulating ROS levels without cytotoxicity using light (610 nm wavelength) illumination. The reinforced angiogenic efficacy of illuminated hMSCcx is based on the increased gap junctional interaction by enhanced fibronectin. hMSCcx engraftment is significantly improved in our novel MS patch by means of ROS tolerative structure of hMSCcx, leading to robust wound-healing outcomes in a mouse wound model. This study provides a new method to overcome the limitations of conventional cell sheets and spheroid therapy.

Ceria Nanoparticles as Copper Chaperones that Activate SOD1 for Synergistic Antioxidant Therapy to Treat Ischemic Vascular Diseases.

All exogenous nanomaterials undergo rapid biotransformation once injected into the body and fall short of executing the intended purpose. Here, it is reported that copper-deposited ceria nanoparticles (CuCe NPs) exhibit enhanced antioxidant effects over pristine ceria nanoparticles, as the released copper buffers the depletion of glutathione while providing the bioavailable copper as a cofactor for the antioxidant enzyme, superoxide dismutase 1. The upregulated intracellular antioxidants along with the ceria nanoparticles synergistically scavenge reactive oxygen species and promote anti-inflammation and M2 polarization of macrophages by modulating signal transducer and activator of transcription 1 and 6 (STAT1 and STAT6). The therapeutic effect of CuCe NPs is demonstrated in ischemic vascular diseases (i.e., murine models of hindlimb ischemia and myocardial infarction) in which the copper-deposition affords increased perfusion and alleviation in tissue damage. The results provide rationale that metal oxide nanomaterials can be designed in a way to induce the upregulation of specific biological factors for optimal therapeutic performance.

Development of Hetero-Cell Type Spheroids Via Core-Shell Strategy for Enhanced Wound Healing Effect of Human Adipose-Derived Stem Cells.

BACKGROUND: Stem cell-based therapies have been developed to treat various types of wounds. Human adipose-derived stem cells (hADSCs) are used to treat skin wounds owing to their outstanding angiogenic potential. Although recent studies have suggested that stem cell spheroids may help wound healing, their cell viability and retention rate in the wound area require improvement to enhance their therapeutic efficacy. METHODS: We developed a core-shell structured spheroid with hADSCs in the core and human dermal fibroblasts (hDFs) in the outer part of the spheroid. The core-shell structure was formed by continuous centrifugation and spheroid incubation. After optimizing the method for inducing uniform-sized core-shell spheroids, cell viability, cell proliferation, migration, and therapeutic efficacy were evaluated and compared to those of conventional spheroids. RESULTS: Cell proliferation, migration, and involucrin expression were evaluated in keratinocytes. Tubular assays in human umbilical vein endothelial cells were used to confirm the improved skin regeneration and angiogenic efficacy of core-shell spheroids. Core-shell spheroids exhibited exceptional cell viability under hypoxic cell culture conditions that mimicked the microenvironment of the wound area. CONCLUSION: The improvement in retention rate, survival rate, and angiogenic growth factors secretion from core-shell spheroids may contribute to the increased therapeutic efficacy of stem cell treatment for skin wounds.

Silica-Based Advanced Nanoparticles For Treating Ischemic Disease.

Recently, various attempts have been made to apply diverse types of nanoparticles in biotechnology. Silica nanoparticles (SNPs) have been highlighted and studied for their selective accumulation in diseased parts, strong physical and chemical stability, and low cytotoxicity. SNPs, in particular, are very suitable for use in drug delivery and bioimaging, and have been sought as a treatment for ischemic diseases. In addition, mesoporous silica nanoparticles have been confirmed to efficiently deliver various types of drugs owing to their porous structure. Moreover, there have been innovative attempts to treat ischemic diseases using SNPs, which utilize the effects of Si ions on cells to improve cell viability, migration enhancement, and phenotype modulation. Recently, external stimulus-responsive treatments that control the movement of magnetic SNPs using external magnetic fields have been studied. This review addresses several original attempts to treat ischemic diseases using SNPs, including particle synthesis methods, and presents perspectives on future research directions.

Phototoxicity-free blue light for enhancing therapeutic angiogenic efficacy of stem cells.

Low-level light therapy (LLLT) is a safe and noninvasive technique that has drawn attention as a new therapeutic method to treat various diseases. However, little is known so far about the effect of blue light for LLLT due to the generation of reactive oxygen species (ROS) that can cause cell damage. We introduced a blue organic light-emitting diode (bOLED) as a safe and effective light source that could generate a low amount of heat and luminance compared to conventional light sources (e.g., light-emitting diodes). We compared phototoxicity of bOLED light with different light fluences to human adipose-derived stem cells (hADSC). We further explored molecular mechanisms involved in the therapeutic efficacy of bOLED for enhancing angiogenic properties of hADSC, including intracellular ROS control in hADSCs. Using optimum conditions of bOLED light proposed in this study, photobiomodulation and angiogenic properties of hADSCs were enhanced. These findings might open new methods for using blue light in LLLT. Such methods can be implemented in future treatments for ischemic disease.

Facile and scalable fabrication of exosome-mimicking nanovesicles through PEGylated lipid detergent-aided cell extrusion.

We report a scalable fabrication method to generate exosome-mimicking nanovesicles (ENVs) by using a biocompatible, cell-binding lipid detergent during cell extrusion. A PEGylated mannosylerythritol lipid (MELPEG) detergent was rationally engineered to strongly associate with phospholipid membranes to increase cell membrane deformability and the corresponding friction force during extrusion and to enhance the dispersibility of ENVs. Compared to cell extrusion without detergent, cell extrusion in the presence of MELPEG increased the ENV production yield by approximately 20 times and cellular protein content per MELPEG-functionalized ENV by approximately 2-fold relative to that of unmodified ENVs. We verified that MELPEG strongly binds to ENV membranes and increases membrane deformability via expansion/swelling while preserving the integrity of the phospholipid bilayer structure. The results highlight that the MELPEG-aided cell extrusion process broadly applies to various cell lines; hence, it could be helpful in the production of ENVs for tissue regeneration, drug delivery, and cancer nanomedicine.

Increasing angiogenic efficacy of conditioned medium using light stimulation of human adipose-derived stem cells.

Conditioned medium (CM) contains various therapeutic molecules produced by cells. However, the low concentration of therapeutic molecules in CM is a major challenge for successful tissue regeneration. Here, we aim to develop a CM enriched in angiogenic paracrine factors for the treatment of ischemic diseases. Combining spheroidal culture and light irradiation significantly upregulates the angiogenic factor expression in human adipose-derived stem cells (hADSCs). Spheroids of light-irradiated hADSCs (SR group) show significantly enhanced expression of angiogenic paracrine factors compared with spheroids without light stimulation. Enhanced viability, migration, and angiogenesis are observed in cells treated with CM derived from the SR group. Furthermore, we performed in vivo experiments using a mouse hindlimb ischemia model; the results demonstrate that CM derived from densely cultured spheroids of light-irradiated hADSCs induced increased angiogenesis in vivo. In conclusion, our proposed approach of using light to stimulate stem cells may overcome the major drawbacks of CM-based therapies.

Silica-Capped and Gold-Decorated Silica Nanoparticles for Enhancing Effect of Gold Nanoparticle-Based Photothermal Therapy.

BACKGROUND: Various methods based on gold nanoparticles (AuNPs) have been applied to enhance the photothermal effect. Among these methods, combining gold nanoparticles and stem cells has been suggested as a new technique for elevating the efficiency of photothermal therapy (PT) in terms of enhancing tumor targeting effect. However, to elicit the efficiency of PT using gold nanoparticles and stem cells, delivering large amounts of AuNPs into stem cells without loss should be considered. METHODS: AuNPs, AuNPs-decorated silica nanoparticles, and silica-capped and AuNPs-decorated silica nanoparticles (SGSs) were synthesized and used to treat human mesenchymal stem cells (hMSCs). After evaluating physical properties of each nanoparticle, the concentration of each nanoparticle was estimated based on its cytotoxicity to hMSCs. The amount of AuNPs loss from each nanoparticle by exogenous physical stress was evaluated after exposing particles to a gentle shaking. After these experiments, in vitro and in vivo photothermal effects were then evaluated. RESULTS: SGS showed no cytotoxicity when it was used to treat hMSCs at concentration up to 20 µg/mL. After intravenous injection to tumor-bearing mice, SGS-laden hMSCs group showed significantly higher heat generation than other groups following laser irradiation. Furthermore, in vivo photothermal effect in the hMSC-SGS group was significantly enhanced than those in other groups in terms of tumor volume decrement and histological outcome. CONCLUSION: Our results suggest that additional silica layer in SGSs could protect AuNPs from physical stress induced AuNPs loss. The strategy applied in SGS may offer a prospective method to improve PT.