scholarly journals Hydrogel–mesh composite for wound closure

2021 ◽  
Vol 118 (28) ◽  
pp. e2103457118
Author(s):  
Yang Gao ◽  
Xiuyuan Han ◽  
Jiaojiao Chen ◽  
Yudong Pan ◽  
Meng Yang ◽  
...  
Keyword(s):  
Surgical Mesh ◽  
Wound Closure ◽  
Polymer Network ◽  
Large Area ◽  
Covalent Bonds ◽  
Chitosan Hydrogel ◽  
Living Tissues ◽  
High Mechanical Stress ◽  
Tissue Form

During operations, surgical mesh is commonly fixed on tissues through fasteners such as sutures and staples. Attributes of surgical mesh include biocompatibility, flexibility, strength, and permeability, but sutures and staples may cause stress concentration and tissue damage. Here, we show that the functions of surgical mesh can be significantly broadened by developing a family of materials called hydrogel–mesh composites (HMCs). The HMCs retain all the attributes of surgical mesh and add one more: adhesion to tissues. We fabricate an HMC by soaking a surgical mesh with a precursor, and upon cure, the precursor forms a polymer network of a hydrogel, in macrotopological entanglement with the fibers of the surgical mesh. In a surgery, the HMC is pressed onto a tissue, and the polymers in the hydrogel form covalent bonds with the tissue. To demonstrate the concept, we use a poly(N-isopropylacrylamide) (PNIPAAm)/chitosan hydrogel and a polyethylene terephthalate (PET) surgical mesh. In the presence a bioconjugation agent, the chitosan and the tissue form covalent bonds, and the adhesion energy reaches above 100 J⋅m−2. At body temperature, PNIPAAm becomes hydrophobic, so that the hydrogel does not swell and the adhesion is stable. Compared with sutured surgical mesh, the HMC distributes force over a large area. In vitro experiments are conducted to study the application of HMCs to wound closure, especially on tissues under high mechanical stress. The performance of HMCs on dynamic living tissues is further investigated in the surgery of a sheep.

Neurotoxicity of Pesticides: The Roadmap for the Cubic Mode of Action

2020 ◽  
Vol 27 (1) ◽  
pp. 54-77 ◽  
Author(s):  
Bogdan Bumbăcilă ◽  
Mihai V. Putz
Keyword(s):  
Biological Activity ◽  
Wiener Index ◽  
Laboratory Animals ◽  
Covalent Bonds ◽  
Organophosphate Compounds ◽  
Sar Studies ◽  
Structure Activity ◽  
Cubic Structure

Pesticides are used today on a planetary-wide scale. The rising need for substances with this biological activity due to an increasing consumption of agricultural and animal products and to the development of urban areas makes the chemical industry to constantly investigate new molecules or to improve the physicochemical characteristics, increase the biological activities and improve the toxicity profiles of the already known ones. Molecular databases are increasingly accessible for in vitro and in vivo bioavailability studies. In this context, structure-activity studies, by their in silico - in cerebro methods, are used to precede in vitro and in vivo studies in plants and experimental animals because they can indicate trends by statistical methods or biological activity models expressed as mathematical equations or graphical correlations, so a direction of study can be developed or another can be abandoned, saving financial resources, time and laboratory animals. Following this line of research the present paper reviews the Structure-Activity Relationship (SAR) studies and proposes a correlation between a topological connectivity index and the biological activity or toxicity made as a result of a study performed on 11 molecules of organophosphate compounds, randomly chosen, with a basic structure including a Phosphorus atom double bounded to an Oxygen atom or to a Sulfur one and having three other simple covalent bonds with two alkoxy (-methoxy or -ethoxy) groups and to another functional group different from the alkoxy groups. The molecules were packed on a cubic structure consisting of three adjacent cubes, respecting a principle of topological efficiency, that of occupying a minimal space in that cubic structure, a method that was called the Clef Method. The central topological index selected for correlation was the Wiener index, since it was possible this way to discuss different adjacencies between the nodes in the graphs corresponding to the organophosphate compounds molecules packed on the cubic structure; accordingly, "three dimensional" variants of these connectivity indices could be considered and further used for studying the qualitative-quantitative relationships for the specific molecule-enzyme interaction complexes, including correlation between the Wiener weights (nodal specific contributions to the total Wiener index of the molecular graph) and the biochemical reactivity of some of the atoms. Finally, when passing from SAR to Q(uantitative)-SAR studies, especially by the present advanced method of the cubic molecule (Clef Method) and its good assessment of the (neuro)toxicity of the studied molecules and of their inhibitory effect on the target enzyme - acetylcholinesterase, it can be seen that a predictability of the toxicity and activity of different analogue compounds can be ensured, facilitating the in vivo experiments or improving the usage of pesticides.

scholarly journals Overexpression of the Oral Mucosa-Specific microRNA-31 Promotes Skin Wound Closure

2019 ◽  
Vol 20 (15) ◽  
pp. 3679 ◽  
Author(s):  
Lin Chen ◽  
Alyne Simões ◽  
Zujian Chen ◽  
Yan Zhao ◽  
Xinming Wu ◽  
...  
Keyword(s):  
Wound Healing ◽  
Oral Mucosa ◽  
Wound Closure ◽  
Expression Patterns ◽  
Skin Wound ◽  
Skin Wound Healing ◽  
Specific Expression ◽  
Keratinocyte Proliferation

Wounds within the oral mucosa are known to heal more rapidly than skin wounds. Recent studies suggest that differences in the microRNAome profiles may underlie the exceptional healing that occurs in oral mucosa. Here, we test whether skin wound-healing can be accelerating by increasing the levels of oral mucosa-specific microRNAs. A panel of 57 differentially expressed high expresser microRNAs were identified based on our previously published miR-seq dataset of paired skin and oral mucosal wound-healing [Sci. Rep. (2019) 9:7160]. These microRNAs were further grouped into 5 clusters based on their expression patterns, and their differential expression was confirmed by TaqMan-based quantification of LCM-captured epithelial cells from the wound edges. Of these 5 clusters, Cluster IV (consisting of 8 microRNAs, including miR-31) is most intriguing due to its tissue-specific expression pattern and temporal changes during wound-healing. The in vitro functional assays show that ectopic transfection of miR-31 consistently enhanced keratinocyte proliferation and migration. In vivo, miR-31 mimic treatment led to a statistically significant acceleration of wound closure. Our results demonstrate that wound-healing can be enhanced in skin through the overexpression of microRNAs that are highly expressed in the privileged healing response of the oral mucosa.

scholarly journals Facile sonochemical-assisted synthesis of orthorhombic phase black phosphorus/rGO hybrids for effective photothermal therapy

Nanophotonics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 3023-3034
Author(s):  
Weiyuan Liang ◽  
Dou Wang ◽  
Xiaohui Ren ◽  
Chenchen Ge ◽  
Hanyue Wang ◽  
...  
Keyword(s):  
Electrode Materials ◽  
Orthorhombic Phase ◽  
Cost Effective ◽  
Black Phosphorus ◽  
Antitumor Effects ◽  
Covalent Bonds ◽  
Preparation Conditions ◽  
Reduced Graphene

AbstractTwo-dimensional black phosphorus (BP) has been demonstrated to be promising in photoelectronic devices, electrode materials, and biomedicine owing to its outstanding properties. However, the application of BP has been hindered by harsh preparation conditions, high costs, and easy degradation in ambient condition. Herein, we report a facile and cost-effective strategy for synthesis of orthorhombic phase BP and a kind of BP-reduced graphene oxide (BP/rGO) hybrids in which BP remains stable for more than 4 weeks ascribed to the formation of phosphorus-carbon covalent bonds between BP and rGO as well as the protection effect of the unique wrinkle morphology of rGO nanosheets. Surface modification BP/rGO hybrids (PEGylated BP/rGO) exhibit excellent photothermal performance with photothermal conversion efficiency as high as 57.79% at 808 nm. The BP/rGO hybrids exhibit enhanced antitumor effects both in vitro and in vivo, showing promising perspectives in biomedicine.

scholarly journals Survival and Proliferation under Severely Hypoxic Microenvironments Using Cell-Laden Oxygenating Hydrogels

2021 ◽  
Vol 12 (2) ◽  
pp. 30
Author(s):  
Shabir Hassan ◽  
Berivan Cecen ◽  
Ramon Peña-Garcia ◽  
Fernanda Roberta Marciano ◽  
Amir K. Miri ◽  
...  
Keyword(s):  
Prolonged Release ◽  
Therapeutic Approaches ◽  
Encapsulated Cells ◽  
Hypoxic Conditions ◽  
Skeletal Myoblasts ◽  
Artificial Tissue ◽  
Delivery Platform ◽  
Living Tissues

Different strategies have been employed to provide adequate nutrients for engineered living tissues. These have mainly revolved around providing oxygen to alleviate the effects of chronic hypoxia or anoxia that result in necrosis or weak neovascularization, leading to failure of artificial tissue implants and hence poor clinical outcome. While different biomaterials have been used as oxygen generators for in vitro as well as in vivo applications, certain problems have hampered their wide application. Among these are the generation and the rate at which oxygen is produced together with the production of the reaction intermediates in the form of reactive oxygen species (ROS). Both these factors can be detrimental for cell survival and can severely affect the outcome of such studies. Here we present calcium peroxide (CPO) encapsulated in polycaprolactone as oxygen releasing microparticles (OMPs). While CPO releases oxygen upon hydrolysis, PCL encapsulation ensures that hydrolysis takes place slowly, thereby sustaining prolonged release of oxygen without the stress the bulk release can endow on the encapsulated cells. We used gelatin methacryloyl (GelMA) hydrogels containing these OMPs to stimulate survival and proliferation of encapsulated skeletal myoblasts and optimized the OMP concentration for sustained oxygen delivery over more than a week. The oxygen releasing and delivery platform described in this study opens up opportunities for cell-based therapeutic approaches to treat diseases resulting from ischemic conditions and enhance survival of implants under severe hypoxic conditions for successful clinical translation.

scholarly journals Is a diluted seawater-based solution safe and effective on human nasal epithelium?

2021 ◽  
Author(s):  
Song Huang ◽  
Samuel Constant ◽  
Barbara De Servi ◽  
Marisa Meloni ◽  
Amina Saaid ◽  
...  
Keyword(s):  
Wound Repair ◽  
Wound Closure ◽  
Isotonic Saline ◽  
Nasal Epithelium ◽  
Mucin Secretion ◽  
Nasal Irrigation ◽  
Tissue Integrity ◽  
Human Nasal Epithelium ◽  
Pre Treatment

Abstract Purpose Nasal irrigation is an effective method for alleviating several nasal symptoms and regular seawater-based nasal irrigation is useful for maintaining nasal hygiene which is essential for appropriate functioning of the nose and for preventing airborne particles including some pollutants, pathogens, and allergens from moving further in the respiratory system. However, safety studies on seawater-based nasal irrigation are scarce. In this study, the safety and efficacy of a diluted isotonic seawater solution (Stérimar Nasal Hygiene, SNH) in maintaining nasal homeostasis were evaluated in vitro. Methods Safety was assessed by measuring tissue integrity via transepithelial electrical resistance (TEER). Efficacy was measured by mucociliary clearance (MCC), mucin secretion, and tissue re-epithelization (wound repair) assays. All assays were performed using a 3D reconstituted human nasal epithelium model. Results In SNH-treated tissues, TEER values were statistically significantly lower than the untreated tissues; however, the values were above the tissue integrity limit. SNH treatment significantly increased MCC (88 vs. 36 µm/s, p < 0.001) and mucin secretion (1717 vs. 1280 µg/ml, p < 0.001) as compared to untreated cultures. Faster wound closure profile was noted upon pre-SNH treatment as compared to classical isotonic saline solution pre-treatment (90.5 vs. 50.7% wound closure 22 h after wound generation). Conclusion SNH did not compromise the integrity of the nasal epithelium in vitro. Furthermore, SNH was effective for removal of foreign particles through MCC increase and for enhancing wound repair on nasal mucosa.

Fabrication of gelatin/sodium alginate-poly (3-hydroxybutyric acid) bilayer electrospun biosheet as wound healing material in nursing care on pediatric fracture surgery

2020 ◽  
pp. 152808372097634
Author(s):  
Daiqi Jiang ◽  
Zaiju Tong ◽  
Lingjun Peng ◽  
Lingzhi Zhang ◽  
Qianzi Ruan ◽  
...  
Keyword(s):  
Wound Healing ◽  
Sodium Alginate ◽  
Wound Closure ◽  
Skin Wound ◽  
Tissue Formation ◽  
Hydroxybutyric Acid ◽  
Physiochemical Properties ◽  
Pediatric Fracture ◽  
Fracture Surgery

Novel the bilayered electrospun biosheet with rapid cell mimiciking and proliferative efficacy will be suitable for wound healing application. The optimized concentration of gelatin (G) and sodium alginate (A) biosheet with nanofibrous Poly (3-hydroxybutyric acid) (P) as a bilayered elctrospun matrix through electrospinning. The engineered GAP bilayered biosheet involves tissue formation at extra cellular matrix (ECM) which further characterized its function in vitro and invivo. Here we fabricated GAP which exhibit better physiochemical properties, biological and mechanical properties with superior prosomes it enhance air passable at skin wounds. The Bilayered biosheet matrix possess better biocompatibility, cell adherence, fructuous and cell to cell interactions evaluated using cell lines. Furthermore, GAP bilayered matrix regulates growth factors to attain maximum wound closure efficiency during invivo. Thus, the fabricated GAP electrospun biosheet would be a possible wound dressing for skin wound applications.

Transforming growth factor-alpha enhances alveolar epithelial cell repair in a new in vitro model

1994 ◽  
Vol 267 (6) ◽  
pp. L728-L738 ◽  
Author(s):  
F. Kheradmand ◽  
H. G. Folkesson ◽  
L. Shum ◽  
R. Derynk ◽  
R. Pytela ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epithelial Cell ◽  
Wound Repair ◽  
Wound Closure ◽  
Transforming Growth Factor ◽  
Alveolar Epithelial Cell ◽  
Alveolar Epithelial ◽  
Factor Alpha ◽  
Vitro Model

Alveolar epithelial type II cells are essential for regenerating an intact alveolar barrier after destruction of type I cells in vivo. The first objective of these experimental studies was to develop an in vitro model to quantify alveolar epithelial cell wound repair. The second objective was to investigate mechanisms of alveolar epithelial cell wound healing by studying the effects of serum and transforming growth factor-alpha (TGF-alpha) on wound closure. Primary cultures of rat alveolar type II cells were prepared by standard methods and grown to form confluent monolayers in 48 h. Then a wound was made by denuding an area (mean initial area of 2.1 +/- 0.6 mm2) of the monolayer. Re-epithelialization of the denuded area over time in the presence or absence of serum was measured using quantitative measurements from time-lapse video microscopy. The half time of wound healing was significantly enhanced in the presence of serum compared with serum-free conditions (2.4 +/- 0.2 vs. 17.4 +/- 0.8 h, P < 0.001). We then tested the hypothesis that TGF-alpha is an important growth factor for stimulating wound repair of alveolar epithelial cells. Exogenous addition of TGF-alpha in serum-free medium resulted in a significantly more rapid wound closure, and, furthermore, the addition of a monoclonal antibody to TGF-alpha in the presence of serum significantly decreased fourfold the rate of wound closure. Measurement of internuclear cell distance confirmed that both cell motility and cell spreading were responsible for closure of the wound. These data demonstrate that 1) the mechanisms of alveolar cell repair can be studied in vitro and that 2) TGF-alpha is a potent growth factor that enhances in vitro alveolar epithelial cell wound closure.

scholarly journals Yb3+-containing chitosan hydrogels induce B-16 melanoma cell anoikis via a Fak-dependent pathway

2019 ◽  
Vol 8 (1) ◽  
pp. 645-660 ◽  
Author(s):  
Yu Miao ◽  
Jiawei Lu ◽  
Junhui Yin ◽  
Changchun Zhou ◽  
Yaping Guo ◽  
...  
Keyword(s):  
Acetic Acid Solution ◽  
Tumor Model ◽  
In Vivo Studies ◽  
High Recurrence Rate ◽  
Mixed Solution ◽  
Chitosan Hydrogel ◽  
Chitosan Hydrogels ◽  
Dermal Cells

AbstractMelanoma is the most lethal dermal tumor, and a high recurrence rate and skin defects are two main serious problems. An antimelanoma material,which effectively inhibits tumor recurrence and possesses excellent biocompatibility, is urgently needed to treat melanoma. In this study, we developed a novel antitumor Yb3+ [Yb(NO3)3]containing chitosan hydrogel (Yb-CS hydrogel) by dissolving Yb(NO3)3 and chitosan in acetic acid solution and forming composite hydrogels by a freeze-drying process after adding NaOH to the mixed solution. In vitro studies demonstrated that the Yb3+ produces effect of inducing cell death in Yb-CS hydrogel. Moreover, we found that the Yb-CS hydrogel inhibited a focal adhesion kinase (FAK)-dependent signaling pathway and induced B-16 cell anoikis. However, the Yb-CS hydrogel was less effective on L929 normal mouse dermal cells. In vivo studies showed that the Yb-CS hydrogel inhibited the recurrence of melanoma in a mouse bare xenograft tumor model. We concluded that the Yb-CS hydrogel could potentially be used in the antimelanoma field, especially in the inhibition of melanoma recurrence.

scholarly journals Continuous Delivery of Stromal Cell-Derived Factor-1 from Alginate Scaffolds Accelerates Wound Healing

2010 ◽  
Vol 19 (4) ◽  
pp. 399-408 ◽  
Author(s):  
Sina Y. Rabbany ◽  
Joseph Pastore ◽  
Masaya Yamamoto ◽  
Tim Miller ◽  
Shahin Rafii ◽  
...  
Keyword(s):  
Wound Healing ◽  
Stromal Cell ◽  
Wound Closure ◽  
Tissue Injury ◽  
Unmet Need ◽  
Novel Therapy ◽  
Yorkshire Pigs ◽  
Stromal Cell Derived Factor

Proper wound diagnosis and management is an increasingly important clinical challenge and is a large and growing unmet need. Pressure ulcers, hard-to-heal wounds, and problematic surgical incisions are emerging at increasing frequencies. At present, the wound-healing industry is experiencing a paradigm shift towards innovative treatments that exploit nanotechnology, biomaterials, and biologics. Our study utilized an alginate hydrogel patch to deliver stromal cell-derived factor-1 (SDF-1), a naturally occurring chemokine that is rapidly overexpressed in response to tissue injury, to assess the potential effects SDF-1 therapy on wound closure rates and scar formation. Alginate patches were loaded with either purified recombinant human SDF-1 protein or plasmid expressing SDF-1 and the kinetics of SDF-1 release were measured both in vitro and in vivo in mice. Our studies demonstrate that although SDF-1 plasmid- and protein-loaded patches were able to release therapeutic product over hours to days, SDF-1 protein was released faster (in vivo Kd 0.55 days) than SDF-1 plasmid (in vivo Kd 3.67 days). We hypothesized that chronic SDF-1 delivery would be more effective in accelerating the rate of dermal wound closure in Yorkshire pigs with acute surgical wounds, a model that closely mimics human wound healing. Wounds treated with SDF-1 protein ( n = 10) and plasmid ( n = 6) loaded patches healed faster than sham ( n = 4) or control ( n = 4). At day 9, SDF-1-treated wounds significantly accelerated wound closure (55.0 ± 14.3% healed) compared to nontreated controls (8.2 ± 6.0%, p < 0.05). Furthermore, 38% of SDF-1-treated wounds were fully healed at day 9 (vs. none in controls) with very little evidence of scarring. These data suggest that patch-mediated SDF-1 delivery may ultimately provide a novel therapy for accelerating healing and reducing scarring in clinical wounds.

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