Formulation and Characterization of a Novel Oxidized Alginate-Gelatin-Silk Fibroin Bioink with the Aim of Skin Regeneration.

Background: In the present study, a novel bioink was suggested based on the oxidized alginate (OAlg), gelatin (GL), and silk fibroin (SF) hydrogels. Methods: The composition of the bioink was optimized by the rheological and printability measurements, and the extrusion-based 3D bioprinting process was performed by applying the optimum OAlg-based bioink. Results: The results demonstrated that the viscosity of bioink was continuously decreased by increasing the SF/GL ratio, and the bioink displayed a maximum achievable printability (92 ± 2%) at 2% (w/v) of SF and 4% (w/v) of GL. Moreover, the cellular behavior of the scaffolds investigated by MTT assay and live/dead staining confirmed the biocompatibility of the prepared bioink. Conclusion: The bioprinted OAlg-GL-SF scaffold could have the potential for using in skin tissue engineering applications, which needs further exploration.

In-vitro Comparison of Occluding Effect of Fluoride Varnish and Diode Laser Irradiation with Fluoride Varnish and Er,Cr:YSGG Laser Irradiation on Dentinal Tubules of the Cervical Root Area of the Tooth.

Background and purpose:Dentin hypersensitivity (DH) is a sharp, short dental pain which originates from exposed dentin surfaces in response to thermal, evaporative, tactile, osmotic, chemical or electrical stimuli. Research showed that dentin tubule occlusion can lead to pain remission. Our goal was to evaluate the dentinal tubules in the cervical area of root teeth that are occluded by fluoride varnish, diode laser irradiation, and erbium laser irradiation. Materials and methods: This is an in vitro single-blind study. Twenty-four samples of extracted third molars were divided into four groups: control (A), fluoride varnish (B), fluoride varnish and diode laser (C) and fluoride varnish and Er,Cr:YSGG laser (D). After applying varnish and different lasers, the tubule diameter and number of open tubules were examined by SEM. Data were analyzed by SPSS 23 software. Results:In this research, there was no significant difference between groups C and D (ñ=0.999), although there were substantially more open tubules in the control group than groups C (ñ=0.004) and D (ñ=0.003). The mean diameter of tubules in the four groups was statistically different (ñ <0.001), and the descending order of tubule diameter was A > B > C > D. Conclusion:Using diode and erbium laser in combination with sodium fluoride varnish had a significant effect on the reduction of dentinal tubule diameter and their occlusion; thus, these therapies can be used to treat dentin hypersensitivity.

Effects of probiotic supplementation with weight reducing intervention on anthropometric measures, body composition, eating behavior, and related hormone levels in patients with food addiction and weight regain after bariatric surgery: a study protocol for a randomized clinical trial.

BACKGROUND: One of the unfortunate events after bariatric surgery is the weight regain, which occurs in some patients. Food addiction is an eating disorder related to the brain-intestinal axis and can be effective in weight regain after bariatric surgery. In addition, the gut microbiome plays a vital role in eating behaviors, including food addiction. So, this study will aim to evaluate the effects of probiotic supplementation with a weight-reducing diet and cognitive behavioral therapy on anthropometric measures, body composition, eating behavior, and related hormone levels, leptin, oxytocin, and serotonin, in patients with food addiction and weight regain after bariatric surgery. METHODS: We will carry out a triple-blinded randomized clinical trial for 12 weeks to evaluate the effect of probiotic supplementation with a weight-reducing diet and cognitive behavioral therapy on anthropometric measures, body composition, eating behavior, and related hormone levels including leptin, oxytocin, and serotonin, in patients with food addiction and weight regain after bariatric surgery. DISCUSSION: Based on the available evidence, probiotic supplementation by modifying the intestinal microbiome can improve food addiction and subsequent weight loss. TRIAL REGISTRATION: Iranian Registry of Clinical Trials IRCT20220406054437N1 Registered on 2022-06-01.

The association of dietary approach to stop hypertension (DASH) diet with hospitalization risk in patients with COVID-19.

Background and aim: Given the importance of dietary habits in the immune system, the current study aimed at investigating the association between Dietary Approach to Stop Hypertension (DASH) diet and risk of hospitalization due to COVID-19. Methods: Dietary data of 141 patients with COVID-19 were collected using 147-item food frequency questionnaire. DASH score in this cross-sectional study was calculated based on eight components, including fruits, vegetables, legumes and nuts and seeds, whole grains, low-fat dairy, red or processed meats, sweetened beverages, and sodium. Multivariable logistic regression models were applied to estimate the OR and 95% CI for hospitalization due to COVID-19 in each tertile of DASH score. Results: Mean ± SD of DASH score in inpatients (n=74) and outpatients (n= 87) was 22.5 ± 4.57 and 25.34 ± 4.23, respectively. The risk of hospitalization in the highest tertile of DASH score was 81% lower than the lowest tertile (OR=0.19, 95%CI: 0.07-0.55, P trend = 0.001 after adjustment for age, sex, BMI, energy intake). Also, more intake of fruits, vegetables and low-fat dairy products and less intake of sodium, red and processed meat were each significantly associated with reduced risk of hospitalization due to COVID-19. Conclusions: Our data provide evidence that adherence to DASH-style diet was associated with lower risk of hospitalization due to COVID-19.

Sustained release of sulforaphane by bioactive extracellular vesicles for neuroprotective effect on chick model.

Novel studies have shown neurological treatment possibilities with extracellular vesicles (EVs) as natural particles with a special composition that are produced by different cell types. Their stability, natural structure, composition, and bioavailability make them good candidates as drug vehicles. Here, EVs were isolated from amniotic fluid (AF) through differential centrifugation, and characterized for size (<200 nm), structure, and composition, their effectiveness on the human PC12 cell line, and brain of chick embryos exposed to sodium valproate (animal autistic model). Sulforaphane (SFN) was employed as a bioactive compound and then encapsulated into Evs using three methods including passive (incubation), active (sonication), and active-passive (sonication-incubation). Further, the loading and in vitro releases of SFN fitted the Korsmeyer-Peppas (R2  = 0.99) kinetic model by non-Fickian diffusion case II (n = 0.44, passive loading) and Fickian diffusion case I (n = 0.41, active and active-passive loading). SFN-loaded EVs (SFN@EVs; 11 µM: 103 nM) stimulated hPC-12 cell proliferation. The gene expression analysis revealed that SFN@EVs could upregulate Nrf2 and reduce IL-6 expression. Eventually, histopathological results of the coronal cross-section of the chick embryos brain showed treatment with SFN@EVs. This treatment illustrated normality in the gray and white matter and the orientation of the bipolar neurons. Our findings showed EVs' potentially acting as a gene expression regulator in autism spectrum disorder.

Preparation and characterization of injectable gelatin/alginate/chondroitin sulfate/α-calcium sulfate hemihydrate composite paste for bone repair application.

In this study, a group of injectable composite pastes with a novel formulation consisting of two inorganic components: α-calcium sulfate hemihydrate (α-CSH, P/L = 1.8-2.1 g/ml) and calcium-deficient hydroxyapatite (CDHA, P/L = 0.1 g/ml) nanoparticles; and three biopolymers: gelatin (2, 4 wt. %), alginate (1, 1.5 wt. %), and chondroitin sulfate (0.5 wt. %) were carefully prepared and thoroughly characterized with commensurate characterizations. The composite sample composed of gelatin (2 wt. %), alginate (1.5 wt. %), chondroitin sulfate (0.5 wt. %), and also CDHA nanoparticles and α-CSH with P/L ratios of 0.1 and 2.1 g/ml, respectively, exhibited optimal properties in terms of injectability, anti-washout performance, and rheological characteristics. After 14 days of immersion of the chosen sample in the simulated body fluid medium, a dense layer of apatite was formed on the surface of the composite paste. The cellular in vitro tests, such as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay (MTT), alkaline phosphatase assay, 4',6-diamidino-2-phenylindole staining, and cellular attachment, revealed the desirable response of MG-63 cells to the composite paste. The chondroitin sulfate significantly improved the injectability, anti-washout performance, and cellular response of the samples. Considering the promising features of the composite paste prepared in this research work, it could be considered as an alternative injectable bioactive material for bone repair applications.[Formula: see text].

3D Bioprinting of Polycaprolactone-Based Scaffolds for Pulp-Dentin Regeneration: Investigation of Physicochemical and Biological Behavior.

In this study, two structurally different scaffolds, a polycaprolactone (PCL)/45S5 Bioglass (BG) composite and PCL/hyaluronic acid (HyA) were fabricated by 3D printing technology and were evaluated for the regeneration of dentin and pulp tissues, respectively. Their physicochemical characterization was performed by field emission scanning electron microscopy (FESEM) equipped with energy dispersive spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), atomic force microscopy (AFM), contact angle, and compressive strength tests. The results indicated that the presence of BG in the PCL/BG scaffolds promoted the mechanical properties, surface roughness, and bioactivity. Besides, a surface treatment of the PCL scaffold with HyA considerably increased the hydrophilicity of the scaffolds which led to an enhancement in cell adhesion. Furthermore, the gene expression results showed a significant increase in expression of odontogenic markers, e.g., dentin sialophosphoprotein (DSPP), osteocalcin (OCN), and dentin matrix protein 1 (DMP-1) in the presence of both PCL/BG and PCL/HyA scaffolds. Moreover, to examine the feasibility of the idea for pulp-dentin complex regeneration, a bilayer PCL/BG-PCL/HyA scaffold was successfully fabricated and characterized by FESEM. Based on these results, it can be concluded that PCL/BG and PCL/HyA scaffolds have great potential for promoting hDPSC adhesion and odontogenic differentiation.

Tuning the biomimetic behavior of hybrid scaffolds for bone tissue engineering through surface modifications and drug immobilization.

Bone defects arising from injury and/or disease are a common and debilitating clinical lesion. While the development of tissue microenvironments utilizing biomimetic constructs is an emerging approach for bone tissue engineering. In this context, bioactive glass nanoparticles (BGNPs) were embedded within polycaprolactone (PCL) scaffolds. The scaffolds exhibit an engineered unidirectional pore structure which are surface activated via oxygen plasma to allow immobilization of simvastatin (SIM) on the pore surface. Microscopic observation indicated the surface modification did not disturb the lamellar orientation of the pores improving the biomimetic formation of hydroxyapatite. Mathematically modelled release profiles reveal that the oxygen plasma pre-treatment can be utilized to modulate the release profile of SIM from the scaffolds. With the release mechanism controlled by the balance between the diffusion and erosion mechanisms. Computational modelling shows that Human Serum Albumin and Human α2-macroglobulin can be utilized to increase SIM bioavailability for cells via a molecular docking mechanism. Cellular studies show positive MG-63 cell attachment and viability on optimized scaffolds with alkaline phosphatase activity enhanced along with enhanced expression of osteocalcoin biomarker.

The potential impact of polyethylenimine on biological behavior of 3D-printed alginate scaffolds.

Three-dimensional (3D) printing using biocompatible materials is a novel technology having a great potential for fabricating precise 3D scaffolds for tissue engineering. Alginate hydrogel undergoes unstable swelling and degradation properties as well as suffers from poor cell adhesion due to the lack of cell binding domains. These limit its applications in tissue engineering. In this study, 3D-printed alginate scaffolds were coated by branch polyethylenimine (PEI) to overcome the limitation of alginate because the branch PEI is a cationic polymer with a large number of active N-H groups. The results indicated that surface modification of 3D-printed alginate scaffolds using an appropriate concentration of PEI potentially promoted the fibroblast cells functions in 3D-printed alginate scaffolds, increased cell adhesion, cell proliferation and cell spreading through providing a large amount of N-H groups and increasing hydrophilicity of the surface. The degradation rate of alginate was degraded by interaction between N-H groups in PEI and -COO- groups in alginate structure and followed by the formation strong barrier layer in the interface of alginate and PEI. Therefore, ALG-PEI scaffolds can be a good candidate for tissue engineering and wound dressing applications.

Mussel-inspired polydopamine induced the osteoinductivity to ice-templating PLGA-gelatin matrix for bone tissue engineering application.

In this study, poly(lactic-co-glycolic acid) (PLGA)-gelatin scaffolds were fabricated using the freeze-casting technique. Polydopamine (PDA) coating was applied on the surface of scaffolds to enhance the hydrophilicity, bioactivity, and cellular behavior of the composite constructs. Further, the synergistic effect of PDA coating and lamellar microstructure of scaffolds was evaluated on the promotion of properties. Based on morphological observations, freeze-casting constructs showed lamellar pore channels while the uniformity and pore size were slightly affected by deposition of PDA. The hydrophilicity and swelling capacity of the scaffolds were assessed using contact angle measurement and phosphate buffered saline absorption ratio. The results indicated a significant increment in water-matrix interactions following surface modification. The evaluation of the biodegradation ratio revealed the higher degree of degradation in PDA-coated samples owing to the presence of hydrophilic functional groups in the chemical structure of PDA. On the other hand, the bioactivity potential of PDA in the simulated body fluid solution confirmed the possibility of using coated constructs as a bone reconstructive substitute. The improvement of cellular attachment and filopodia formation in PDA-contained matrixes was the other benefit of the coating process. Furthermore, cellular proliferation and ALP activity were enhanced after PDA coating. The suggested PDA-coated PLGA-gelatin scaffolds can be applied in bone tissue regeneration.

Preparation and characterization of nano MnO-CaLs as a green catalyst for oxidation of styrene.

Hydrophilic nano MnO is shown to have significant stability in aqueous media for oxidation of styrene. Different catalysts have been used to synthesis styrene oxide, but MnO-CaL is considered the efficient and selective catalyst to produce styrene oxide. In general, this paper reported especial strategy for synthesis of novel nano MnO that stabilized with oleic acid in chloroform and changing nature of its stabilizer by exchanging oleic acid with lignosulfunate and displays its catalytic activity towards selective oxidation of styrene. The catalyst has shown good selectivity in oxidation of styrene by changing temperature. Finding the optimal conditions for reaction and determining the best time and temperature for achieving the ideal product and reducing the side products are among the issues discussed in this article. MnO-CaLs leads to selective oxidation of styrene to styrene epoxide at low temperature. By increasing the temperatures, benzaldehyde and partially 2-phenyl acetaldehyde are also produced as by-products. Furthermore, the nano catalyst could be recycled several times without any clear changing in activity, which makes nano catalyst economic and environmentally friendly.

Increasing the effectiveness of oxaliplatin using colloidal immunoglobulin G nanoparticles: Synthesis, cytotoxicity, interaction, and release studies.

A novel biomacromolecule was prepared for a stabilizer sustained anticancer drug release system. Colloidal immunoglobulin G (IgG) nanoparticles (IgGNP) were synthesized and then characterized using FT-IR, SEM, zeta sizer, and AFM. Moreover, the formation of spherical shape IgGNP with an appropriate average size (144.56 ± 2 nm) and a narrow distribution for the drug release was confirmed. Also, the conjugation of oxaliplatin (OX) to IgGNP (OX@IgGNP) was demonstrated via the combination of spectroscopy and physical analyses. In this regard, the interaction was spantaneous with static quenching mechanism. OX caused well dispersity with no agglomeration on IgGNP with an average size of 142.31 ± 4 nm. Furthermore, the encapsulation efficiency (%EE) and drug loading (%DL) percentages were determined. Accordingly, the release behavior indicated that OX was sustained from IgGNP more than IgG (approximately 150 h) and the highest release amount of OX (100 %) was obtained at acidic medium (pH 5.5). Notably, the kinetic model was zero order and release mechanism followed by diffusion and Fick's model at neutral medium and combination of diffusion and swelling controlled and non-Fickian model at acidic medium. In addition, the anticancer effect of OX@IgGNP was evaluated on the human breast cancer cell lines, MCF-7 using MTT assay and DAPI staining that showed a remarkable efficacy, while the cytotoxicity in human fibroblast cell lines, HFFF2 has decreased. In this study, gene expression was investigated using real time PCR, which verified IgGNP induced programmed cell death in MCF-7 breast cancer cell more effectively than free OX. Subsequently, a novel nano scale biological macromolecule can be introduced as a sustained and prolonged anticancer drug release.

Decoration of electrical conductive polyurethane-polyaniline/polyvinyl alcohol matrixes with mussel-inspired polydopamine for bone tissue engineering.

Electrospinning is a versatile technology for the fabrication of nanofibrous matrixes to regenerate defects. This study aims to develop a functionalized and electroconductive polymeric matrix to improve rat bone marrow mesenchymal stem cell adhesion, proliferation, and differentiation. Herein, the influence of the chemical composition of the substrate on homogeneous modification of the surface with mussel-inspired polydopamine (PDA) is focused. Accordingly, the deposition of PDA on the surface was proved by Fourier transform infrared spectroscopy. Morphologies of the scaffolds demonstrated homogeneous decoration of the polyvinyl alcohol (PVA)/polyurethane (PU)-polyaniline (PANI) matrixes with PDA, while a lower density of mussel-inspired polymer was observed in bare PU-PANI constructs. Although uniform and dense precipitation of PDA reduced conductivity of scaffolds 1.2 times compared with the samples with a low density of the PDA, 1.1 and 1.2 times enhancement in tensile strength and Young's modulus, respectively, were the strength of the applied process, especially in bone tissue engineering area. Contact angle measurements demonstrated about two times reduction in measured values, which shows improvement in hydrophilicity of PDA-modified PVA/PU-PANI fibers compared with PDA-coated PU-PANI ones. Swelling ratio and mass loss ratio calculations revealed enhancement in measured values as a function of homogeneous and dense coating, which arise from hydrophilicity of the polymeric substrate. The bioactivity test indicated that a dense layer of PDA strongly supports formations of hydroxyapatite-like crystals. Moreover, homogeneous decoration of conductive matrixes with PDA showed suitable cell viability, adhesion, and spreading while cell-scaffolds interactions improved under electrical stimulation. Higher expression of alkaline phosphatase and secretion of Collagen I under the electrical field proved the applicability of modified electroconductive scaffolds for further preclinical and clinical studies to introduce as a reconstructive bone substitute.

Bioactive and biostable hyaluronic acid-pullulan dermal hydrogels incorporated with biomimetic hydroxyapatite spheres.

In this study, hyaluronic acid-pullulan injectable hydrogels were incorporated with biomimetic hydroxyapatite spheres and were modified using silane coupling agents in order to improve the physicochemical, mechanical, and biological performance of hydrogels. So the biomimetic hydroxyapatite spheres were synthesized through immersion of gelatin-siloxane microspheres in the simulated body fluid. The results of field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction spectra confirmed the formation of hydroxyapatite on the surface of hybrid spheres. The morphology observation of the prepared hydrogels confirmed the uniform distribution of hydroxyapatite spheres in gel structure. The chemical characterization proved the possible interactions between the polymers and the created complex with a silane coupling agent to provide more durability. Improvement of storage modulus and viscosity indicated the positive role of hydroxyapatite spheres on the stability and long-lasting durability of hydrogels. A slight reduction was observed in the absorption capacity and water retention in hybrid hydrogels; even though, the great resistance to enzymatic biodegradation led to higher durability of hydroxyapatite-contained gels. Improvement in L-929 fibroblast cell adhesion and spreading especially around the biomimetic hydroxyapatite spheres along with higher cell viability demonstrated the initial potential of hydrogels for further pre-clinical and clinical studies in order to recommend the gels for dermal rejuvenation applications.

Synthesis and characterization of timolol maleate-loaded quaternized chitosan-based thermosensitive hydrogel: A transparent topical ocular delivery system for the treatment of glaucoma.

The chitosan-based thermosensitive hydrogel is one of the attractive in situ forming drug delivery systems that are suggested for ophthalmic applications. However, the use of this thermogel has been limited by non-transparency, relatively low solubility and prolonged gelation time. In this study, a convenient approach has been reported to develop transparent thermosensitive hydrogel with suitable cytocompatibility and gelation properties for glaucoma treatment. After obtaining the optimum quaternization conditions, the developed in-situ gelling formulation of quaternized chitosan was achieved by mixing sodium hydrogen carbonate with ß-glycerophosphate as a gelling agent. The formulation was a solution below or at room temperature and turned to a transparent hydrogel around ocular surface temperature within several minutes. The results of thermal and rheological evaluations demonstrated that adding sodium hydrogen carbonate has a synergic effect in enhancing the thermosensitivity of the hydrogel. Also, the prepared hydrogels based on quaternized chitosan presented obvious porous architectures, good swelling, and degradability. Hemolysis and cytotoxicity evaluations suggested that the developed hydrogels indicated good biocompatibility as a drug carrier. Finally, the in vitro release profile of timolol maleate as an anti-glaucoma model drug showed the initial burst release in the early hours and a steady linear release of drug from the hydrogel over 1 week. The obtained results confirmed that the developed hydrogel can be considered as an efficient drug delivery candidate for glaucoma therapy.

Serum and Salivary Level of Nitric Oxide (NOx) and CRP in Oral Lichen Planus (OLP) Patients.

STATEMENT OF THE PROBLEM: Oral lichen planus (OLP) is a chronic inflammatory oral mucosal disease with unclear etiology while a few cases of disease become malignant. PURPOSE: This study aimed to evaluate the level of nitric oxide (NOx) and C-reactive protein (CRP) as oxidative stress and inflammation status in sample of OLP patients. MATERIALS AND METHOD: In this case-control study, serum and salivary NOx and CRP levels were evaluated in twenty two OLP patients as the case group confirmed by clinical and histopathological diagnosis, and twenty two healthy control groups collected from Tooba Oral Pathology Laboratory in Sari in 2016. The data were analyzed by using independent-samples t-test, Mann-Whitney U-test and Chi-square by using SPSS version 21. The statistical significant level was considered at p< 0.05. RESULTS: Salivary and serum NOx levels in case group showed statistically significantly higher than healthy control group (p= 0.035 and p= 0.001, respectively). CRP values were significantly higher both in serum (p= 0.001) and in saliva (p= 0.035). A significant correlation was found between CRP and NOx values in serum (r= 0.521, p= 0.0001) and saliva (r= 0.427, p= 0.045). CONCLUSION: Oxidative stress causes damage to organs in the human body. Correct understanding of oxidative stress and its association with free radicals and inflammatory markers related to oral disease are important for effective treatments. The results of the study advocate the effects of NOx and CRP levels in pathogenesis of OLP. Therefore, antioxidant drugs might probably be considered in the treatment of OLP.

A bioinspired 3D shape olibanum-collagen-gelatin scaffolds with tunable porous microstructure for efficient neural tissue regeneration.

There are a number of procedures for regeneration of injured nerves; however, tissue engineering scaffolds seems to be a promising approach for recovery of the functionality of the injured nerves. Consequently, in this study, olibanum-collagen-gelatin scaffolds were fabricated by freeze-cast technology. For this purpose, the olibanum and collagen were extracted from natural sources. The effect of solidification gradient on microstructure and properties of scaffolds was investigated. Scanning electron microscopy micrographs showed the formation of lamellar-type microstructure in which the average pore size reduced with an increase in freezing rate. According to the results, the prepared scaffolds at lower freezing rate showed a slight reduction in mechanical strength while the swelling and biodegradation ratio were increased due to the presence of larger pores and unidirectional channels. The composition of scaffolds and oriented microstructure improved cellular interaction. In addition, scaffolds with lower freezing rate exhibited promising results in terms of adhesion, spreading, and proliferation. In brief, the synthesized scaffolds at lower solidification rate have the potential for more in vitro and in vivo analyses to regeneration of neural defects.

Additively manufactured small-diameter vascular grafts with improved tissue healing using a novel SNAP impregnation method.

The vascular network has a complex architecture such as branches, curvatures, and bifurcations which is even more complicated in view of individual patients' defect anatomy requiring custom-specifically designed vascular implants. In this work, 3D printing is used to overcome these challenges and a new shorter impregnation method was developed to incorporate S-nitroso-N-acetyl-d-penicillamine (SNAP) as a nitric oxide (NO) donor to printed grafts. The 3D-printed small-diameter vascular grafts (SDVGs) were impregnated with SNAP solution during SNAP synthesis (S1) or with SNAP dissolved in methanol (S2). The advantage of the newly developed S1 impregnation method is the elimination of the synthesis step by direct impregnation inside the S1 solution. Scanning electron microscopy imaging reveals the successful crystal formation in both methods. The results demonstrate that both S1- and S2-impregnated grafts, after covering with polycaprolactone topcoat, can release NO in a controlled manner and in the physiological range (0.5-4.0 × 10-10 mol cm-2 min-1 ) over a 15 days period. The created grafts with a NO-releasing surface have also shown bactericidal effect while the healing properties of the implant were improved by promoting migration and proliferation of endothelial cells (ECs). These results suggest that incorporation of 3D printing technology with the newly developed S1 impregnation of SNAP can optimize and shorten the manufacturing process of the next generation of patient-based antibacterial SDVGs with a higher attraction for ECs.

Mussel-inspired polydopamine-mediated surface modification of freeze-cast poly (ε-caprolactone) scaffolds for bone tissue engineering applications.

There are many methods used to fabricate the scaffolds for tissue regeneration, among which freeze casting has attracted a great deal of attention due to the capability to create a unidirectional structure. In this study, polycaprolactone (PCL) scaffolds were fabricated by freeze-casting technology in order to create porous microstructure with oriented open-pore channels. To induce biomineralization, and to improve hydrophilicity and cell interactions, mussel-inspired polydopamine (PDA) was coated on the surface of the freeze-cast PCL constructs. Then, the synergistic effects of oriented microstructure and deposited layer on efficient reconstruction of injured bone were studied. Microscopic observations demonstrated that, the coated layer did not show any special change in lamellar microstructure of the scaffolds. Water-scaffold interactions were evaluated by contact angle measurements, and they demonstrated strong enhancement in the hydrophilicity of the polymeric scaffolds after PDA coating. Biodegradation ratio and water uptake evaluation confirmed an increase in the measured values after PDA precipitation. The biomineralization of the PDA-coated scaffolds was characterized by field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD). Obtained results confirmed biomineralization of the constructs after a 28-day immersion in a simulated body fluid (SBF) solution. Mechanical analysis demonstrated higher compressive strength after PDA coating. L929 fibroblast cell viability and attachment illustrated that PDA-coated PCL scaffolds are able to support cell adhesion and proliferation. The increased secretion of alkaline phosphatase (ALP) after culturing osteosarcoma cell lines (MG-63) revealed the initial capability of scaffolds to induce bone regeneration. Therefore, the PDA-coated scaffolds introduce a promising approach for bone tissue engineering application.

Fabrication and characterisation of super-paramagnetic responsive PLGA-gelatine-magnetite scaffolds with the unidirectional porous structure: a physicochemical, mechanical, and in vitro evaluation.

Architecture and composition of Scaffolds are influential factors in the regeneration of defects. Herein, synthesised iron oxide (magnetite) nanoparticles (MNPs) by co-precipitation technique were evenly distributed in polylactic-co-glycolic acid (PLGA)-gelatine Scaffolds. Hybrid structures were fabricated by freeze-casting method to the creation of a matrix with tunable pores. The synthesised MNPs were characterised by transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, and vibrating sample magnetometer analysis. Scanning electron microscopy micrographs of porous Scaffolds confirmed the formation of unidirectional microstructure, so that pore size measurement indicated the orientation of pores in the direction of solvent solidification. The addition of MNPs to the PLGA-gelatine Scaffolds had no particular effect on the morphology of the pores, but reduced slightly pore size distribution. The MNPs contained constructs demonstrated increased mechanical strength, but a reduced absorption capacity and biodegradation ratio. Stability of the MNPs and lack of iron release was the point of strength in this investigation and were determined by atomic absorption spectroscopy. The evolution of rat bone marrow mesenchymal stem cells performance on the hybrid structure under a static magnetic field indicated the potential of super-paramagnetic constructs for further pre-clinical and clinical studies in the field of neural regeneration.