[Extracellular Matrix Stiffness Induces Mitochondrial Morphological Heterogeneity via AMPK Activation]. / 细胞外基质硬度通过AMPK调控干细胞线粒体的形态异质性.

Objective: To investigate the mechanical responses of mitochondrial morphology to extracellular matrix stiffness in human mesenchymal stem cells (hMSCs) and the role of AMP-activated protein kinase (AMPK) in the regulation of mitochondrial mechanoresponses. Methods: Two polyacrylamide (PAAm) hydrogels, a soft one with a Young's modulus of 1 kPa and a stiff one of 20 kPa, were prepared by changing the monomer concentrations of acrylamide and bis-acrylamide. Then, hMSCs were cultured on the soft and stiff PAAm hydrogels and changes in mitochondrial morphology were observed using a laser confocal microscope. Western blot was performed to determine the expression and activation of AMPK, a protein associated with mitochondrial homeostasis. Furthermore, the activation of AMPK was regulated on the soft and stiff matrixes by AMPK activator A-769662 and the inhibitor Compound C, respectively, to observe the morphological changes of mitochondria. Results: The morphology of the mitochondria in hMSCs showed heterogeneity when there was a change in gel stiffness. On the 1 kPa soft matrix, 74% mitochondria exhibited a dense, elongated filamentous network structure, while on the 20 kPa stiff matrix, up to 63.3% mitochondria were fragmented or punctate and were sparsely distributed. Western blot results revealed that the phosphorylated AMPK (p-AMPK)/AMPK ratio on the stiff matrix was 1.6 times as high as that on the soft one. Immunofluorescence assay results revealed that the expression of p-AMPK was elevated on the hard matrix and showed nuclear localization, which indicated that the activation of intracellular AMPK increased continuously along with the increase in extracellular matrix stiffness. When the hMSCs on the soft matrix were treated with A-769662, an AMPK activator, the mitochondria transitioned from a filamentous network morphology to a fragmented morphology, with the ratio of filamentous network decreasing from 74% to 9.5%. Additionally, AMPK inhibition with Compound C promoted mitochondrial fusion on the stiff matrix and significantly reduced the generation of punctate mitochondria. Conclusion: Extracellular matrix stiffness regulates mitochondrial morphology in hMSCs through the activation of AMPK. Stiff matrix promotes the AMPK activation, resulting in mitochondrial fission and the subsequent fragmentation of mitochondria. The impact of matrix stiffness on mitochondrial morphology can be reversed by altering the level of AMPK phosphorylation.

3D in vitro hydrogel models to study the human lung extracellular matrix and fibroblast function.

The pulmonary extracellular matrix (ECM) is a macromolecular structure that provides mechanical support, stability and elastic recoil for different pulmonary cells including the lung fibroblasts. The ECM plays an important role in lung development, remodeling, repair, and the maintenance of tissue homeostasis. Biomechanical and biochemical signals produced by the ECM regulate the phenotype and function of various cells including fibroblasts in the lungs. Fibroblasts are important lung structural cells responsible for the production and repair of different ECM proteins (e.g., collagen and fibronectin). During lung injury and in chronic lung diseases such as asthma, idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD), an abnormal feedback between fibroblasts and the altered ECM disrupts tissue homeostasis and leads to a vicious cycle of fibrotic changes resulting in tissue remodeling. In line with this, using 3D hydrogel culture models with embedded lung fibroblasts have enabled the assessment of the various mechanisms involved in driving defective (fibrotic) fibroblast function in the lung's 3D ECM environment. In this review, we provide a summary of various studies that used these 3D hydrogel models to assess the regulation of the ECM on lung fibroblast phenotype and function in altered lung ECM homeostasis in health and in chronic respiratory disease.

Evaluation of osteogenic potential of demineralized dentin matrix hydrogel for bone formation.

OBJECTIVES: Dentin, the bulk material of the tooth, resemble the bone's chemical composition and is considered a valuable bone substitute. In the current study, we assessed the cytotoxicity and osteogenic potential of demineralized dentin matrix (DDM) in comparison to HA nanoparticles (n-HA) on bone marrow mesenchymal stem cells (BMMSCs) using a hydrogel formulation. MATERIALS AND METHODS: Human extracted teeth were minced into particles and treated via chemical demineralization using ethylene diamine tetra-acetic acid solution (EDTA) to produce DDM particles. DDM and n-HA particles were added to the sodium alginate then, the combination was dripped into a 5% (w/v) calcium chloride solution to obtain DDM hydrogel (DDMH) or nano-hydroxyapatite hydrogel (NHH). The particles were evaluated by dynamic light scattering (DLS) and the hydrogels were evaluated via scanning electron microscope (SEM). BMMSCs were treated with different hydrogel concentrations (25%, 50%, 75% and neat/100%) and cell viability was evaluated using MTT assay after 72 h of culture. Collagen-I (COL-I) gene expression was studied with real-time quantitative polymerase chain reaction (RT-qPCR) after 3 weeks of culture and alkaline phosphatase (ALP) activity was assessed using enzyme-linked immune sorbent assay (ELISA) over 7th, 10th, 14th and 21st days of culture. BMMSCs seeded in a complete culture medium were used as controls. One-way ANOVA was utilized to measure the significant differences in the tested groups. RESULTS: DLS measurements revealed that DDM and n-HA particles had negative values of zeta potential. SEM micrographs showed a porous microstructure of the tested hydrogels. The viability results revealed that 100% concentrations of either DDMH or NHH were cytotoxic to BMMSCs after 72 h of culture. However, the cytotoxicity of 25% and 50% concentrations of DDMH were not statistically significant compared to the control group. RT-qPCR showed that COL-I gene expression was significantly upregulated in BMMSCs cultured with 50% DDMH compared to all other treated or control groups (P < 0.01). ELISA analysis revealed that ALP level was significantly increased in the groups treated with 50% DDMH compared to 50% NHH after 21 days in culture (P < 0.001). CONCLUSION: The injectable hydrogel containing demineralized dentin matrix was successfully formulated. DDMH has a porous structure and has been shown to provide a supporting matrix for the viability and differentiation of BMMSCs. A 50% concentration of DDMH was revealed to be not cytotoxic to BMMSCs and may have a great potential to promote bone formation ability.

Locust bean gum hydrogels are bioadhesive and improve indole-3-carbinol cutaneous permeation: influence of the polysaccharide concentration

Abstract The locust bean gum (LBG) is a polysaccharide with thickening, stabilizing and gelling properties and it has been used in the preparation of pharmaceutical formulations. Hydrogels (HGs) are obtained from natural or synthetic materials that present interesting properties for skin application. This study aimed to develop HGs from LBG using indole-3-carbinol (I3C) as an asset model for cutaneous application. HGs were prepared by dispersing LBG (2%, 3% and 4% w/v) directly in cold water. The formulations showed content close to 0.5 mg/g (HPLC) and pH ranging from 7.25 to 7.41 (potentiometry). The spreadability factor (parallel plate method) was inversely proportional to LBG concentration. The rheological evaluation (rotational viscometer) demonstrated a non-Newtonian pseudoplastic flow behavior (Ostwald De Weale model), which is interesting for cutaneous application. The HET-CAM evaluation showed the non-irritating characteristic of the formulations. The bioadhesive potential demonstrated bioadhesion in a concentration-dependent manner. Permeation in human skin using Franz cells showed that the highest LBG concentration improved the skin distribution profile with greater I3C amounts in the viable skin layers. The present study demonstrated the feasibility of preparing HGs with LBG and the formulation with the highest polymer concentration was the most promising to transport active ingredients through the skin.

Development and clinical application of hydrogel formulations containing papain and urea for wound healing

Abstract Hydrogels are used for wound treatment, as they may contain one or more active components and protect the wound bed. Papain is one of the active substances that have been used with this purpose, alongside urea. In this paper, carboxypolymethylene hydrogels containing papain (2% and 10% concentrations) and urea (5% concentration) were produced. Physical-chemical stability was performed at 0, 7, 15 and 30 days at 2-8ºC, 25ºC and 40ºC, as well as the rheological aspects and proteolytic activity of papain by gel electrophoresis. Clinical efficacy of the formulations in patients with lower limb ulcers was also evaluated in a prospective, single-center, randomized, double-blind and comparative clinical trial. The results showed 7-day stability for the formulations under 25ºC, in addition to approximately 100% and 15% of protein activity for 10% and 2% papain hydrogel, respectively. The rheological profile was non-Newtonian for the 10% papain hydrogel tested. There were no significant differences regarding the mean time for healing of the lesions, although 10% papain presented a better approach to be used in all types of tissue present in the wound bed.

Tunable PEG Hydrogels for Discerning Differential Tumor Cell Response to Biomechanical Cues.

Increased extracellular matrix (ECM) density in the tumor microenvironment has been shown to influence aspects of tumor progression such as proliferation and invasion. Increased matrix density means cells experience not only increased mechanical properties, but also a higher density of bioactive sites. Traditional in vitro ECM models like Matrigel and collagen do not allow these properties to be investigated independently. In this work, a poly(ethylene glycol)-based scaffold is used which modifies with integrin-binding sites for cell attachment and matrix metalloproteinase 2 and 9 sensitive sites for enzyme-mediated degradation. The polymer backbone density and binding site concentration are independently tuned and the effect each of these properties and their interaction have on the proliferation, invasion, and focal complex formation of two different tumor cell lines is evaluated. It is seen that the cell line of epithelial origin (Hs 578T, triple negative breast cancer) proliferates more, invades less, and forms more mature focal complexes in response to an increase in matrix adhesion sites. Conversely, the cell line of mesenchymal origin (HT1080, fibrosarcoma) proliferates more in 2D culture but less in 3D culture, invades less, and forms more mature focal complexes in response to an increase in matrix stiffness.

Biophysical properties of hydrogels for mimicking tumor extracellular matrix.

The extracellular matrix (ECM) is an essential component of the tumor microenvironment. It plays a critical role in regulating cell-cell and cell-matrix interactions. However, there is lack of systematic and comparative studies on different widely-used ECM mimicking hydrogels and their properties, making the selection of suitable hydrogels for mimicking different in vivo conditions quite random. This study systematically evaluates the biophysical attributes of three widely used natural hydrogels (Matrigel, collagen gel and agarose gel) including complex modulus, loss tangent, diffusive permeability and pore size. A new and facile method was developed combining Critical Point Drying, Scanning Electron Microscopy imaging and a MATLAB image processing program (CSM method) for the characterization of hydrogel microstructures. This CSM method allows accurate measurement of the hydrogel pore size down to nanometer resolution. Furthermore, a microfluidic device was implemented to measure the hydrogel permeability (Pd) as a function of particle size and gel concentration. Among the three gels, collagen gel has the lowest complex modulus, medium pore size, and the highest loss tangent. Agarose gel exhibits the highest complex modulus, the lowest loss tangent and the smallest pore size. Collagen gel and Matrigel produced complex moduli close to that estimated for cancer ECM. The Pd of these hydrogels decreases significantly with the increase of particle size. By assessing different hydrogels' biophysical characteristics, this study provides valuable insights for tailoring their properties for various three-dimensional cancer models.

Construction of in vitro 3-D model for lung cancer-cell metastasis study.

BACKGROUND: Cancer metastasis is the main cause of mortality in cancer patients. However, the drugs targeting metastasis processes are still lacking, which is partially due to the short of effective in vitro model for cell invasion studies. The traditional 2-D culture method cannot reveal the interaction between cells and the surrounding extracellular matrix during invasion process, while the animal models usually are too complex to explain mechanisms in detail. Therefore, a precise and efficient 3-D in vitro model is highly desirable for cell invasion studies and drug screening tests. METHODS: Precise micro-fabrication techniques are developed and integrated with soft hydrogels for constructing of 3-D lung-cancer micro-environment, mimicking the pulmonary gland or alveoli as in vivo. RESULTS: A 3-D in vitro model for cancer cell culture and metastasis studies is developed with advanced micro-fabrication technique, combining microfluidic system with soft hydrogel. The constructed microfluidic platform can provide nutrition and bio-chemical factors in a continuous transportation mode and has the potential to form stable chemical gradient for cancer invasion research. Hundreds of micro-chamber arrays are constructed within the collagen gel, ensuring that all surrounding substrates for tumor cells are composed of natural collagen hydrogel, like the in vivo micro-environment. The 3-D in vitro model can also provide a fully transparent platform for the visual observation of the cell morphology, proliferation, invasion, cell-assembly, and even the protein expression by immune-fluorescent tests if needed. The lung-cancer cells A549 and normal lung epithelial cells (HPAEpiCs) have been seeded into the 3-D system. It is found out that cells can normally proliferate in the microwells for a long period. Moreover, although the cancer cells A549 and alveolar epithelial cells HPAEpiCs have the similar morphology on 2-D solid substrate, in the 3-D system the cancer cells A549 distributed sparsely as single round cells on the extracellular matrix (ECM) when they attached to the substrate, while the normal lung epithelial cells can form cell aggregates, like the structure of normal tissue. Importantly, cancer cells cultured in the 3-D in vitro model can exhibit the interaction between cells and extracellular matrix. As shown in the confocal microscope images, the A549 cells present round and isolated morphology without much invasion into ECM, while starting from around Day 5, cells changed their shape to be spindle-like, as in mesenchymal morphology, and then started to destroy the surrounding ECM and invade out of the micro-chambers. CONCLUSIONS: A 3-D in vitro model is constructed for cancer cell invasion studies, combining the microfluidic system and micro-chamber structures within hydrogel. To show the invasion process of lung cancer cells, the cell morphology, proliferation, and invasion process are all analyzed. The results confirmed that the micro-environment in the 3-D model is vital for revealing the lung cancer cell invasion as in vivo.

Keratose hydrogel for tissue regeneration and drug delivery.

Keratin (KRT), a natural fibrous structural protein, can be classified into two categories: "soft" cytosolic KRT that is primarily found in the epithelia tissues (e.g., skin, the inner lining of digestive tract) and "hard" KRT that is mainly found in the protective tissues (e.g., hair, horn). The latter is the predominant form of KRT widely used in biomedical research. The oxidized form of extracted KRT is exclusively denoted as keratose (KOS) while the reduced form of KRT is termed as kerateine (KRTN). KOS can be processed into various forms (e.g., hydrogel, films, fibers, and coatings) for different biomedical applications. KRT/KOS offers numerous advantages over other types of biomaterials, such as bioactivity, biocompatibility, degradability, immune/inflammatory privileges, mechanical resilience, chemical manipulability, and easy accessibility. As a result, KRT/KOS has attracted considerable attention and led to a large number of publications associated with this biomaterial over the past few decades; however, most (if not all) of the published review articles focus on KRT regarding its molecular structure, biochemical/biophysical properties, bioactivity, biocompatibility, drug/cell delivery, and in vivo transplantation, as well as its applications in biotechnical products and medical devices. Current progress that is directly associated with KOS applications in tissue regeneration and drug delivery appears an important topic that merits a commentary. To this end, the present review aims to summarize the current progress of KOS-associated biomedical applications, especially focusing on the in vitro and in vivo effects of KOS hydrogel on cultured cells and tissue regeneration following skin injury, skeletal muscle loss, peripheral nerve injury, and cardiac infarction.

Synthesis and characterization of chitosan-PVA hydrogel containing PEGylated recombinant epidermal growth factor on cell culture for wound healing substitute

Abstract The aim of the current study was to assess the physicochemical characteristics and wound healing activity of chitosan-polyvinyl alcohol (PVA) crosslinked hydrogel containing recombinant human epidermal growth factor (rh-EGF) or recombinant mouse epidermal growth factor (rm-EGF). The hydrogels were prepared and analyses were made of the morphological properties, viscosity, water absorption capacity, mechanical and bio-adhesive properties. The viscosity of the formulations varied between 14.400 - 48.500 cPs, with the greatest viscosity values determined in K2 formulation. F2 formulation showed the highest water absorption capacity. According to the studies of the mechanical properties, H2 formulation (0.153±0.018 N.mm) showed the greatest adhesiveness and E2 (0.245±0.001 mj/cm2) formulation, the highest bio-adhesion values. Hydrogels were cytocompatible considering in vitro cell viability values of over 76% on human keratinocyte cells (HaCaT, CVCL-0038) and of over 84% on human fibroblast cells (NIH 3T3, CRL-1658) used as a model cell line. According to the BrdU cell proliferation results, B1 (197.82±2.48%) formulation showed the greatest NIH 3T3 and C1 (167.43±5.89%) formulation exhibited the highest HaCaT cell proliferation ability. In addition, the scratch closure assay was performed to assess the wound healing efficiency of formulation and the results obtained in the study showed that F2 formulation including PEGylated rh-EGF had a highly effective role.

Development and Evaluation of a Hydrogel containing Momordica cochinchinensis Spreng Extract for Topical Applications

Abstract The purpose of this research was to develop a hydrogel containing the extract of Gac fruit (Momordica cochinchinensis Spreng) with appropriate physicochemical properties and good dermatological efficacy. The Gac aril fruit was extracted by maceration in dichloromethane, and its antioxidant activity was determined through a DPPH assay. The very low water-solubility of the Gac extract is responsible for its incompatibility with the hydrogel. To overcome this drawback, LabrafacTM PG and Tween 60 were used to develop the hydrogel due to their potent potential for solubilizing the Gac extract. The prepared hydrogels displayed good physical properties, a homogenous orange gel, appropriate pH, and viscosity. After storage in an accelerated condition for six months, the hydrogels of the Gac extract had physical stability and high remaining amounts of beta-carotene and lycopene within the range of 90.25 - 94.61%. The skin efficacy of hydrogel containing the Gac fruit extract was found using 14 healthy female volunteers over a 30-day period of daily application. Topical application of the hydrogel containing the Gac fruit extract, which contains antioxidants, significantly moisturizes the skin and enhanced its elasticity (p ≤ 0.05; ANOVA). This makes it suitable for use as a skin care product

Development and Characterization of a Hydrogel Containing Silver Sulfadiazine for Antimicrobial Topical Applications. Part II: Stability, Cytotoxicity and Silver Release Patterns

Abstract Hydrogels are interesting for use in the treatment of topical wounds due to their virtually zero toxicity, and capacity for extended release of pharmaceuticals. Silver sulfadiazine (SSDZ) is the drug of choice in the treatment of skin burns. The aim of the study was to determine cytotoxicity, antimicrobial activity and stability of a PVA hydrogel with integrated silver sulfadiazine. SSDZ-hydrogels were prepared using 10% (w/w) PVA (either 89% or 99% hydrolyzed) and 1% (w/w) silver sulfadiazine. Cellular viability was assessed via MTS assays, antimicrobial activity via disk-diffusion and accelerated stability tests were carried out with analysis at 0, 30, 60, 90 and 180 days of storage at 40 ± 2 °C and a relative humidity of 75 ± 5%. The parameters evaluated included organoleptic characteristics, moisture, swelling ability, mechanical strength, FTIR, XRD, TGA and DSC, and silver release patterns via XRD and potentiometry. Cell viability tests indicated some cytotoxicity, although within acceptable levels. After 90 days of storage, SSDZ hydrogel samples exhibited a brown coloration, probably due to the formation of Ag or Ag2O nanoparticles. The SSDZ-loaded hydrogels suffered visual and physical changes; however, these changes did not compromise its use as occlusive wound dressings or its antimicrobial properties.

Preparation of liquid-core hydrogel beads using antioxidant-rich Syzygium caryophyllatum fruit pulp as a healthy snack.

Reverse spherification is a common technique used in molecular gastronomy to produce innovative products with an improved texture by shaping a liquid into an edible semisolid sphere that gives a burst in the mouth sensation. In this study, liquid-core hydrogel beads (LHBs) were prepared using Syzygium caryophyllatum fruit pulp adapting reverse-phase molecular gastronomy as a minimal processing technique to promote it as a healthy snack. Three types of hydrogel beads were formulated while considering the stability of LHBs. Long-term hardening of fruit juice in sodium alginate solution and the addition of plasticizer was used as two methods to increase the textural stability of LHBs. Results revealed that the addition of the plasticizer imparted to improve all the physical and textural properties of beads; however, it affects the transparency of the hydrogel membrane as well. Although the plasticizer increased the textural stability of LHBs, prolong inlaying them in it (the plasticizer) contribute to occur adverse consequences on the quality. Hence, the inlaying of LHBs in glycerol for 2 min was selected as the best treatment (HBP1). Since HBP1 had a low hardness (125.00 g) and high resilience (0.21), it imparted a chewing gum-like texture to LHBs. Hence, it (HBP1) can be used as a healthy snack. While HBP1 was capable of retained 90% antioxidant activity of fresh fruit of S. caryophyllatum, total polyphenolic content, 2,2-diphenyl-2-picryl-hydrazyl scavenging activity %, and ferric reducing antioxidant power value of this formulation were 59.50 GAE/g of dried LHBs, 68.96% and 139.69 TE/g of dried LHBs, respectively.

Self-Healing Metallo-Supramolecular Hydrogel Based on Specific Ni2+ Coordination Interactions of Poly(ethylene glycol) with Bistriazole Pyridine Ligands in the Main Chain.

In this study, a supramolecular hydrogel formed by incorporating the 2,6-bis(1,2,3-triazol-4-yl)-pyridine (btp) ligand in the backbone of a polymer prepared by copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) "click" polyaddition reaction of 2,6-diethynylpyridine and diazido-poly(ethylene glycol) is reported. The hydrogelation is selectively triggered by the addition of Ni2+ ions to aqueous copolymer solutions. The gelation and rheological properties could be tuned by the change of metal to ligand ratio and polymer concentration. Interestingly, the hydrogel exhibits a fast (within 2 min) and excellent repeatable autonomic healing capacity without external stimuli. This self-healing behavior may find potential applications for the repairing of metal coatings, in the future.

Safe-by-design development of a topical patch for drug delivery

Few topical products have been developed specifically to treat acute and chronic arthritis and inflammation, using non-steroidal anti-inflammatory drugs (NSAIDs). The lack of dosing accuracy commonly found in locally applied semisolid products for cutaneous use is a critical issue that leads to treatment failure. The aim of the present work is to develop a differentiated and innovative topical patch based on a monolithic hydrogel for ibuprofen skin delivery, in order to provide a safer and accurate way of drug administration along with improved treatment compliance. Topical patches based on hydroxypropylmethylcellulose (HPMC) were optimized in composition, in terms of enhancer and adhesive, supported on a systematic assessment of in vitro release and permeation behavior and adhesion properties. Several mathematical models were used to scrutinize the release mechanisms from the patches. In vitro release kinetics was shown to be mainly driven by diffusion. However, other mechanisms seemed to be also present, supporting the feasibility of using patches for sustained drug delivery. PEG 200 provided the best permeation rate, with a permeation enhancement ratio of ca. 3 times higher, than the commercial reference. The addition of Eudragit L30D 55 to the formulation led to the best adhesion profile, thus achieving a successful development based on a safe-by-design concept.

Growth factor-mediated augmentation of long bones: evaluation of a BMP-7 loaded thermoresponsive hydrogel in a murine femoral intramedullary injection model.

BACKGROUND: Due to our aging population, an increase in proximal femur fractures can be expected, which is associated with impaired activities of daily living and a high risk of mortality. These patients are also at a high risk to suffer a secondary osteoporosis-related fracture on the contralateral hip. In this context, growth factors could open the field for regenerative approaches, as it is known that, i.e., the growth factor BMP-7 (bone morphogenetic protein 7) is a potent stimulator of osteogenesis. Local prophylactic augmentation of the proximal femur with a BMP-7 loaded thermoresponsive hydrogel during index surgery of an osteoporotic fracture could be suitable to reduce the risk of further osteoporosis-associated secondary fractures. The present study therefore aims to test the hypothesis if a BMP-7 augmented hydrogel is an applicable carrier for the augmentation of non-fractured proximal femurs. Furthermore, it needs to be shown that the minimally invasive injection of a hydrogel into the mouse femur is technically feasible. METHODS: In this study, male C57BL/6 mice (n = 36) received a unilateral femoral intramedullary injection of either 100 µl saline, 100 µl 1,4 Butan-Diisocyanat (BDI)-hydrogel, or 100 µl hydrogel loaded with 1 µg of bone morphogenetic protein 7. Mice were sacrificed 4 and 12 weeks later. The femora were submitted to high-resolution X-ray tomography and subsequent histological examination. RESULTS: Analysis of normalized CtBMD (Cortical bone mineral density) as obtained by X-ray micro-computed tomography analysis revealed significant differences depending on the duration of treatment (4 vs 12 weeks; p < 0.05). Furthermore, within different anatomically defined regions of interest, significant associations between normalized TbN (trabecular number) and BV/TV (percent bone volume) were noted. Histology indicated no signs of inflammation and no signs of necrosis and there were no cartilage damages, no new bone formations, or new cartilage tissues, while BMP-7 was readily detectable in all of the samples. CONCLUSIONS: In conclusion, the murine femoral intramedullary injection model appears to be feasible and worth to be used in subsequent studies that are directed to examine the therapeutic potential of BMP-7 loaded BDI-hydrogel. Although we were unable to detect any significant osseous effects arising from the mode or duration of treatment in the present trial, the effect of different concentrations and duration of treatment in an osteoporotic model appears of interest for further experiments to reach translation into clinic and open new strategies of growth factor-mediated augmentation.

Characterization and quantitation of PVP content in a silicone hydrogel contact lens produced by dual-phase polymerization processing.

Polyvinylpyrrolidone (PVP) has been incorporated over the years into numerous hydrogel contact lenses as both a primary matrix component and an internal wetting agent to increase lens wettability. In this study, complementary analytical techniques were used to characterize the PVP wetting agent component of senofilcon A and samfilcon A contact lenses, both in terms of chemical composition and amount present. Photo-differential scanning calorimetry (photo-DSC), gas chromatography with a flame ionization detector (GC-FID), and high-resolution/accurate mass (HR/AM) liquid chromatography-mass spectrometry (LC-MS) techniques confirmed dual phase reaction and curing of the samfilcon A silicone hydrogel material. Gel permeation chromatography (GPC) demonstrated that high molecular weight (HMW) polymer was present in isopropanol (IPA) extracts of both lenses. High-performance liquid chromatography (HPLC) effectively separated hydrophilic PVP from the hydrophobic silicone polymers present in the extracts. Collectively, atmospheric solids analysis probe mass spectrometry (ASAP MS), Fourier transform infrared (FTIR) spectroscopy, 1 H nuclear magnetic resonance (NMR) spectroscopy, GC-FID, and LC-MS analyses of the lens extracts indicated that the majority of NVP is consumed during the second reaction phase of samfilcon A lens polymerization and exists as HMW PVP, similar to the PVP present in senofilcon A. GC-FID analysis of pyrolyzed samfilcon A and senofilcon A indicates fourfold greater PVP in samfilcon A compared with senofilcon A. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1064-1072, 2018.

Appraisal of acute oral toxicity of glucuronoxylan hydrogel from Mimosa pudica seeds

Glucuronoxylan hydrogel (GXH) isolated from M. pudica seeds was assessed for acute toxicology in albino mice that were alienated into four groups. Three groups, i.e., II, III and IV received GXH at a dose of 1, 2 and 5 g/kg, respectively while group I was retained untreated and provided routine diet. After administering GXH, mice were examined for vomiting, diarrhea, allergy and tremors for 8 h. All animals were carefully observed for food and water consumption at 1, 2, 3, 7 and 14 day after administering GXH. At the end of studies, blood samples were drawn for investigation of hematological and biochemical parameters. All animals were sacrificed, relative body weight of vital organs was calculated and their histopathology was studied. It was concluded that there was insignificant difference in body weight, behavioral pattern, food and water intake among treated and control groups. Haematology and biochemistry of blood samples from all groups were found analogous. Histopathological evaluation of vital body organs exhibited no lesions in all groups. Ocular, cardiac and dermal safety of GXH was also established on albino rabbits.

Strain rate dependent hyperelastic stress-stretch behavior of a silica nanoparticle reinforced poly (ethylene glycol) diacrylate nanocomposite hydrogel.

Poly (ethylene glycol) diacrylate (PEGDA) derivatives are important biomedical materials. PEGDA based hydrogels have emerged as one of the popular regenerative orthopedic materials. This work aims to study the mechanical behavior of a PEGDA based silica nanoparticle (NP) reinforced nanocomposite (NC) hydrogel at physiological strain rates. The work combines materials fabrication, mechanical experiments, mathematical modeling and structural analysis. The strain rate dependent stress-stretch behaviors were observed, analyzed and quantified. Visco-hyperelasticity was identified as the deformation mechanism of the nano-silica/PEGDA NC hydrogel. NPs showed significant effect on both initial shear modulus and viscoelastic materials properties. A structure-based quasi-linear viscoelastic (QLV) model was constructed and capable to describe the visco-hyperelastic stress-stretch behavior of the NC hydrogel. A group of unified material parameters was extracted by the model from the stress-stretch curves obtained at different strain rates. Visco-hyperelastic behavior of NP/polymer interphase was not only identified but also quantified. The work could provide guidance to the structural design of next-generation NC hydrogel.

Avaliação da peroxidação lipídica no plasma de ratos submetidos à lesão tecidual e tratados com hidrogel de poliamido de mandioca / Evaluación de la peroxidación de lípidos en plasma de ratas sometidas a lesión tisular y tratadas con hidrogel de poliamida de yuca / Evaluación de la peroxidación de lípidos en plasma de ratas sometidas a lesión tisular y tratadas con hidrogel de poliamida de yuca

As espécies reativas ao oxigênio (EROS) são produzidas como mecanismo de defesa celular, participando dos processos de cicatrização celular. Entretanto, altos níveis de EROS podem causar danos como a peroxidação lipídica (PL). O presente estudo teve como objetivo, verificar os níveis de PL por meio da determinação das substâncias reativas ao ácido tiobarbitúrico (TBARS) no plasma de ratos com lesão tecidual induzida. Foram utilizados 32 ratos machos, Rattus norvegicus albinus da linhagem Wistar, os quais foram pesados e da média ± 10% do peso foram distribuídos em quatro grupos: A ­ controle negativo; B - Vetaglós®; C ­ hidrogel de poliamido de mandioca+ Vetaglós®; D ­ Hidrogel de poliamido de mandioca. Após 21 dias, todos os animais foram anestesiados com isoflurano e foi feita a coleta de sangue por punção cardíaca, e os plasmas foram obtidos após centrifugação, na sequência por superdosagem do anestésico foi realizada a eutanásia. Os níveis de PL nos plasmas dos ratos foram determinados pelo método do TBARS. Não houve diferença significativa entre os grupos em relação à PL, indicando um equilíbrio entre as defesas antioxidantes celulares e os níveis de EROS produzidos durante o processo de cicatrização celular. Essa ausência nos diferentes grupos experimentais, em relação à PL, deixa claro a importância de se contemplar estudos de parâmetros de bioindicadores de estresse oxidativo em protocolos experimentais.

Reactive oxygen species (ROS) are produced as a cellular defense mechanism, participating in the processes of cellular healing. However, high levels of ROS can cause damages such as lipid peroxidation (LPO). This study aimed to verify the levels of LPO through the determination of reactive substances to thiobarbituric acid (TBARS) in rat plasma with induced tissue injury. A total of 32 Rattus norvegicus albinus Wistar were used, with a mean weight ± 10%. They were divided into four groups: A ­ negative control; B - Vetaglós®; C - Polyamide cassava; D - Polyamide cassava + Vetaglós®. After 21 days, all animals were anesthetized with isoflurane and blood was collected by cardiac puncture. Plasma was obtained after centrifugation. Euthanasia was performed with administration of an overdose of inhalational anesthetic previously used. The LPO levels in rat plasma were determined using the TBARS method. There was no significant difference between the groups in relation to LPO, indicating a balance between antioxidant defenses and cellular levels of ROS produced during the cellular healing process. This absence in the different experimental groups in relation to LPO emphasizes the importance of further studies related to the bio-indicator parameters for oxidative stress in experimental protocols.

Las especies reactivas al oxígeno (EROS) se producen como mecanismo de defensa celular, que participan en los procesos de curación celulares. Sin embargo, los altos niveles de EROS pueden causar daños como la peroxidación lipídica (PL). Este estudio tuvo como objetivo verificar los niveles de peroxidación lipídica por sustancias reactivas al ácido tiobarbitúrico (TBARS) en el plasma de ratas con lesión tisular inducida. Se han utilizado 32 ratas machos, Rattus norvegicus albinus de linaje Wistar, que se pesaron y la media ± 10% en peso, y se dividieron en cuatro grupos: A ­ control negativo; B - Vetaglós®; C ­ hidrogel de poliamida de yuca + Vetaglós®; D ­ Hidrogel de poliamida de yuca. Después de 21 días, todos los animales fueron anestesiados con isoflurano y se hizo la extracción de sangre por punción cardiaca, y se obtuvieron los plasmas después de la centrifugación, enseguida con sobredosis de anestésico se realizó la eutanasia. Los niveles de PL en los plasmas de las ratas se determinaron por el método de TBARS. No hubo diferencia significativa entre los grupos en relación a la peroxidación lipídica, lo que indica un equilibrio entre las defensas antioxidantes celulares y los niveles de EROS producidos durante el proceso de curación celular. Esa ausencia en los diferentes grupos experimentales, en relación a la PL, pone de manifiesto la importancia de contemplarse estudios de parámetros de bioindicadores de estrés oxidativo en los protocolos experimentales.