Bioactive fibrous scaffolds with programmable release of polypeptides regulate inflammation and extracellular matrix remodeling

Novel Gel Formulation and Deep Injection Techniques for Lifting Effects in Cosmetic Dermatology

INTRODUCTION

In recent years, the field of aesthetic dermatology has witnessed a surge in demand for minimally invasive procedures aimed at rejuvenating aging skin. This study aims to address this demand by evaluating the effectiveness of the injectable gel in rejuvenating aging skin, particularly by targeting collagen regeneration and lifting effect.

MATERIALS AND METHODS

The study involved 43 participants who underwent three monthly injection sessions targeting retaining ligaments. The injections were administered deeply to ensure proper targeting. Follow-up assessments were conducted after each treatment session and three months after the final injection. Evaluation methods included subjective assessments by both patients and investigators using the Global Aesthetic Improvement Scale (GAIS), as well as objective assessments using a 3D photosystem to measure wrinkle conditions and vectors of traction.

RESULTS

All participants completed the study, with no significant adverse effects observed apart from mild swelling at the injection sites. Despite the high viscosity of HA necessitating the use of a 27 G needle, the injection process was generally comfortable and minimally painful. Subjective evaluations revealed consistent improvements in skin appearance from the first application, which continued to increase throughout the study and remained high even 3 months post-treatment. Objective evaluations demonstrated significant improvements in wrinkle conditions and lifting effects, with a substantial increase in the standard deviation score for wrinkle conditions and the average traction vector length measuring 1.6 mm.

CONCLUSION

The study findings confirm the safety and efficacy of the injectable formula, with high patient satisfaction, noticeable lifting effects, and significant improvements in wrinkle conditions. These results support the use of the injectable as a promising option for non-invasive skin rejuvenation treatments.

Programmable biomaterials for bone regeneration

Programmable biomaterials are distinguished by their ability to adjust properties and functions on demand, in a periodic, reversible, or sequential manner. This contrasts with traditional biomaterials, which undergo irreversible, uncontrolled changes. This review synthesizes key advances in programmable biomaterials, examining their design principles, functionalities and applications in bone regeneration. It charts the transition from traditional to programmable biomaterials, emphasizing their enhanced precision, safety and control, which are critical from clinical and biosafety standpoints. We then classify programmable biomaterials into six types: dynamic nucleic acid-based biomaterials, electrically responsive biomaterials, bioactive scaffolds with programmable properties, nanomaterials for targeted bone regeneration, surface-engineered implants for sequential regeneration and stimuli-responsive release materials. Each category is analyzed for its structural properties and its impact on bone tissue engineering. Finally, the review further concludes by highlighting the challenges faced by programmable biomaterials and suggests integrating artificial intelligence and precision medicine to enhance their application in bone regeneration and other biomedical fields.

Therapeutic Properties of M2 Macrophages in Chronic Wounds: An Innovative Area of Biomaterial-Assisted M2 Macrophage Targeted Therapy

Wound healing is a dynamic, multi-stage process essential for restoring skin integrity. Dysregulated wound healing is often linked to impaired macrophage function, particularly in individuals with chronic underlying conditions. Macrophages, as key regulators of wound healing, exhibit significant phenotypic diversity, ranging from the pro-healing M2 phenotype to the pro-inflammatory M1 phenotype. Imbalances in the M1/M2 ratio or hyperactivation of the M1 phenotype can delay the normal healing. Consequently, strategies aimed at suppressing the M1 phenotype or promoting the shift of local skin macrophages toward the M2 phenotype can potentially treat chronic non-healing wounds. This manuscript provides an overview of macrophages' role in normal and pathological wound-healing processes. It examines various therapeutic approaches targeting M2 macrophages, such as ex vivo-activated macrophage therapy, immunopharmacological strategies, and biomaterial-directed macrophage polarization. However, it also highlights that M2 macrophage therapies and immunopharmacological interventions may have drawbacks, including rapid phenotypic changes, adverse effects on other skin cells, biotoxicity, and concerns related to biocompatibility, stability, and drug degradation. Therefore, there is a need for more targeted macrophage-based therapies that ensure optimal biosafety, allowing for effective reprogramming of dysregulated macrophages and improved therapeutic outcomes. Recent advances in nano-biomaterials have demonstrated promising regenerative potential compared to traditional treatments. This review discusses the progress of biomaterial-assisted macrophage targeting in chronic wound repair and addresses the challenges faced in its clinical application. Additionally, it explores novel design concepts for combinational therapies, such as incorporating regenerative particles like exosomes into dressing materials or encapsulating them in microneedling systems to enhance wound healing rates.

Injectable drug-loaded thermosensitive hydrogel delivery system for protecting retina ganglion cells in traumatic optic neuropathy

Currently, generalized therapy for traumatic optic neuropathy (TON) is lacking. Various strategies have been developed to protect and regenerate retinal ganglion cells (RGCs) after TON. Intravitreal injection of supplements has been approved as a promising approach, although serious concerns, such as low delivery efficacy and pain due to frequent injections, remain. In this study, we tested an injectable thermosensitive hydrogel drug delivery system engineered to deliver ciliary neurotrophic factor (CNTF) and triamcinolone acetonide (TA). The results of rheological studies showed that the prepared drug-loaded hydrogel possessed a suitable mechanical modulus of ∼300 Pa, consistent with that of vitreum. The hydrogel exhibited thermosensitive with sustained drug release performance. In vitro co-culture of the CNTF-loaded hydrogel system with primary RGCs also induced significant axon regeneration, with 38.5% increase in neurite length, indicating the regenerative response of the thermosensitive hydrogel drug delivery system. A Sprague-Dawley rat optic nerve crush model was constructed and applied to determine the neuroprotective and regenerative capacities of the system. The results demonstrated that a single intravitreal injection of the drug-loaded hydrogel (PLGA-PEG-PLGA + TA or PLGA-PEG-PLGA + CNTF) significantly increased RGC survival at both 14 and 28 days. The RGC survival rate was 31.05 ± 1.41% for the drug-loaded hydrogel system (the control group was 16.79 ± 1.50%) at Day 28. These findings suggest that the injectable drug-loaded thermosensitive hydrogel delivery system is a promising therapeutic tool for treating optic nerve degeneration.

L-arginine loading porous PEEK promotes percutaneous tissue repair through macrophage orchestration

Infection and poor tissue repair are the key causes of percutaneous implantation failure. However, there is a lack of effective strategies to cope with due to its high requirements of sterilization, soft tissue healing, and osseointegration. In this work, l-arginine (L-Arg) was loaded onto a sulfonated polyetheretherketone (PEEK) surface to solve this issue. Under the infection condition, nitric oxide (NO) and reactive oxygen species (ROS) are produced through catalyzing L-Arg by inducible nitric oxide synthase (iNOS) and thus play a role in bacteria sterilization. Under the tissue repair condition, L-Arg is catalyzed to ornithine by Arginase-1 (Arg-1), which promotes the proliferation and collagen secretion of L929 and rBMSCs. Notably, L-Arg loading samples could polarize macrophages to M1 and M2 in infection and tissue repair conditions, respectively. The results in vivo show that the L-Arg loading samples could enhance infected soft tissue sealing and bone regeneration. In summary, L-Arg loading sulfonated PEEK could polarize macrophage through metabolic reprogramming, providing multi-functions of antibacterial abilities, soft tissue repair, and bone regeneration, which gives a new idea to design percutaneous implantation materials.

Polyethylenimine-modified graphene quantum dots promote endothelial cell proliferation

Endothelial cell proliferation plays an important role in angiogenesis and treatment of related diseases. The aim of this study was to evaluate the effect of polyethylenimine (PEI)-modified graphene quantum dots (GQDs) gene vectors on endothelial cell proliferation. The GQDs-cationic polymer gene vectors were synthesized by amidation reaction, and used to deliver pZNF580 gene to Human umbilical vein endothelial cells (HUVECs) for promoting their proliferation. The chemical modification of GQDs can adjust gene vectors' surface properties and charge distribution, thereby enhancing their interaction with gene molecules, which could effectively compress the pZNF580 gene. The CCK-8 assay showed that the cell viability was higher than 80% at higher vector concentration (40 μg/mL), demonstrating that the GQDs-cationic polymer gene vectors and their gene complex nanoparticles (NPs) having low cytotoxicity. The results of the live/dead cell double staining assay were consistent with those of the CCK-8 assay, in which the cell viability of the A-GQDs/pZNF580 (94.38 ± 6.39%), C-GQDs-PEI- polylactic acid-co-polyacetic acid (PLGA)/pZNF580 (98.65 ± 6.60%) and N-GQDs-PEI-PLGA/pZNF580 (90.08 ± 1.60%) groups was significantly higher than that of the Lipofectamine 2000/pZNF580 (71.98 ± 3.53%) positive treatment group. The results of transfection and western blot experiments showed that the vector significantly enhanced the delivery of plasmid to HUVECs and increased the expression of pZNF580 in HUVECs. In addition, the gene NPs better promote endothelial cell migration and proliferation. The cell migration rate and proliferation ability of C-GQDs-PEI-PLGA/pZNF580 and N-GQDs-PEI-PLGA/pZNF580 treatment groups were higher than those of Lipofectamine 2000/pDNA treatment group. Modified GQDs possess the potential to serve as efficient gene carriers. They tightly bind gene molecules through charge and other non-covalent interactions, significantly improving the efficiency of gene delivery and ensuring the smooth release of genes within the cell. This innovative strategy provides a powerful means to promote endothelial cell proliferation.

Enhancing cartilage regeneration and repair through bioactive and biomechanical modification of 3D acellular dermal matrix

Acellular dermal matrix (ADM) shows promise for cartilage regeneration and repair. However, an effective decellularization technique that removes cellular components while preserving the extracellular matrix, the transformation of 2D-ADM into a suitable 3D scaffold with porosity and the enhancement of bioactive and biomechanical properties in the 3D-ADM scaffold are yet to be fully addressed. In this study, we present an innovative decellularization method involving 0.125% trypsin and 0.5% SDS and a 1% Triton X-100 solution for preparing ADM and converting 2D-ADM into 3D-ADM scaffolds. These scaffolds exhibit favorable physicochemical properties, exceptional biocompatibility and significant potential for driving cartilage regeneration in vitro and in vivo. To further enhance the cartilage regeneration potential of 3D-ADM scaffolds, we incorporated porcine-derived small intestinal submucosa (SIS) for bioactivity and calcium sulfate hemihydrate (CSH) for biomechanical reinforcement. The resulting 3D-ADM+SIS scaffolds displayed heightened biological activity, while the 3D-ADM+CSH scaffolds notably bolstered biomechanical strength. Both scaffold types showed promise for cartilage regeneration and repair in vitro and in vivo, with considerable improvements observed in repairing cartilage defects within a rabbit articular cartilage model. In summary, this research introduces a versatile 3D-ADM scaffold with customizable bioactive and biomechanical properties, poised to revolutionize the field of cartilage regeneration.

Bioinspired Platelet-Anchored Electrospun Meshes for Tight Inflammation Manipulation and Chronic Diabetic Wound Healing

Tight manipulation of the initial leukocytes infiltration and macrophages plasticity toward the M2 phenotype remain a challenge for diabetic wound healing. Inspired by the platelet function and platelet-macrophage interaction, a platelet-anchored polylactic acid-b-polyethylene glycol-b-polylactic acid (PLA-PEG-PLA) electrospun dressing is developed for inflammatory modulation and diabetic wounds healing acceleration. PLA-PEG-PLA electrospun meshes encapsulated with thymosin β4 (Tβ4) and CaCl2 is fabricated with electrospinning, followed by immersion of electrospun mesh in platelet-rich plasma to firmly anchor the platelets. It is demonstrated that the anchored platelets on electrospun mesh can enhance the initial macrophage recruitment and control the Tβ4 release from electrospun meshes to facilitate the macrophages polarization to the M2 phenotype. The inflammatory regulation promotes the expression of vascular endothelial growth factor and the migration of vascular endothelial cells for angiogenesis, resulting in accelerated diabetic wounds healing. Therefore, this work paved a new way to design platelet-inspired electrospun meshes for inflammation manipulation and diabetic wound healing.

Actin polymerization and depolymerization in developing vertebrates

Development is a complex process that occurs throughout the life cycle. F-actin, a major component of the cytoskeleton, is essential for the morphogenesis of tissues and organs during development. F-actin is formed by the polymerization of G-actin, and the dynamic balance of polymerization and depolymerization ensures proper cellular function. Disruption of this balance results in various abnormalities and defects or even embryonic lethality. Here, we reviewed recent findings on the structure of G-actin and F-actin and the polymerization of G-actin to F-actin. We also focused on the functions of actin isoforms and the underlying mechanisms of actin polymerization/depolymerization in cellular and organic morphogenesis during development. This information will extend our understanding of the role of actin polymerization in the physiologic or pathologic processes during development and may open new avenues for developing therapeutics for embryonic developmental abnormalities or tissue regeneration.

Emergent Peptides of the Antifibrotic Arsenal: Taking Aim at Myofibroblast Promoting Pathways

Myofibroblasts are the principal effector cells driving fibrosis, and their accumulation in tissues is a fundamental feature of fibrosis. Essential pathways have been identified as being central to promoting myofibroblast differentiation, revealing multiple targets for intervention. Compared with large proteins and antibodies, peptide-based therapies have transpired to serve as biocompatible and cost-effective solutions to exert biomimicry, agonistic, and antagonistic activities with a high degree of targeting specificity and selectivity. In this review, we summarize emergent antifibrotic peptides and their utilization for the targeted prevention of myofibroblasts. We then highlight recent studies on peptide inhibitors of upstream pathogenic processes that drive the formation of profibrotic cell phenotypes. We also briefly discuss peptides from non-mammalian origins that show promise as antifibrotic therapeutics. Finally, we discuss the future perspectives of peptide design and development in targeting myofibroblasts to mitigate fibrosis.