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1.
J Biomed Mater Res A ; 2024 Jun 17.
Article in English | MEDLINE | ID: mdl-38884299

ABSTRACT

Despite the significant recent advances in manufacturing materials supporting advanced dental therapies, peri-implantitis still represents a severe complication in dental implantology. Herein, a sol-gel process is proposed to easily deposit antibacterial zirconia coatings onto bulk zirconia, material, which is becoming very popular for the manufacturing of abutments. The coatings' physicochemical properties were analyzed through x-ray diffraction and scanning electron microscopy-energy-dispersive x-ray spectroscopy investigations, while their stability and wettability were assessed by microscratch testing and static contact angle measurements. Uniform gallium-doped tetragonal zirconia coatings were obtained, featuring optimal mechanical stability and a hydrophilic behavior. The biological investigations pointed out that gallium-doped zirconia coatings: (i) displayed full cytocompatibility toward human gingival fibroblasts; (ii) exhibited significant antimicrobial activity against the Aggregatibacter actinomycetemcomitans pathogen; (iii) were able to preserve the commensal Streptococcus salivarius. Furthermore, the proteomic analyses revealed that the presence of Ga did not impair the normal oral microbiota. Still, interestingly, it decreased by 17% the presence of Fusobacterium nucleatum, a gram-negative, strictly anaerobic bacteria that is naturally present in the gastrointestinal tract. Therefore, this work can provide a valuable starting point for the development of coatings aimed at easily improving zirconia dental implants' performance.

2.
Mater Today Bio ; 26: 101072, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38757057

ABSTRACT

Osteoarthritis (OA) is a highly disabling pathology, characterized by synovial inflammation and cartilage degeneration. Orthobiologics have shown promising results in OA treatment thanks to their ability to influence articular cells and modulate the inflammatory OA environment. Considering their complex mechanism of action, the development of reliable and relevant joint models appears as crucial to select the best orthobiologics for each patient. The aim of this study was to establish a microfluidic OA model to test therapies in a personalized human setting. The joint-on-a-chip model included cartilage and synovial compartments, containing hydrogel-embedded chondrocytes and synovial fibroblasts, separated by a channel for synovial fluid. For the cartilage compartment, a Hyaluronic Acid-based matrix was selected to preserve chondrocyte phenotype. Adding OA synovial fluid induced the production of inflammatory cytokines and degradative enzymes, generating an OA microenvironment. Personalized models were generated using patient-matched cells and synovial fluid to test the efficacy of mesenchymal stem cells on OA signatures. The patient-specific models allowed monitoring changes induced by cell injection, highlighting different individual responses to the treatment. Altogether, these results support the use of this joint-on-a-chip model as a prognostic tool to screen the patient-specific efficacy of orthobiologics.

3.
Environ Sci Ecotechnol ; 21: 100397, 2024 Sep.
Article in English | MEDLINE | ID: mdl-38434491

ABSTRACT

Recovering extracellular polymeric substances (EPS) from waste granular sludge offers a cost-effective and sustainable approach for transforming wastewater resources into industrially valuable products. Yet, the application potential of these EPS in real-world scenarios, particularly in paper manufacturing, remains underexplored. Here we show the feasibility of EPS-based biomaterials, derived from anaerobic granular sludges, as novel coating agents in paper production. We systematically characterised the rheological properties of various EPS-based suspensions. When applied as surface sizing agents, these EPS-based biomaterials formed a distinct, ultra-thin layer on paper, as evidenced by scanning electron microscopy. A comprehensive evaluation of water and oil penetration, along with barrier properties, revealed that EPS-enhanced coatings markedly diminished water absorption while significantly bolstering oil and grease resistance. Optimal performance was observed in EPS variants with elevated protein and hydrophobic contents, correlating with their superior rheological characteristics. The enhanced water-barrier and grease resistance of EPS-coated paper can be attributed to its non-porous, fine surface structure and the functional groups in EPS, particularly the high protein content and hydrophobic humic-like substances. This research marks the first demonstration of utilizing EPS from anaerobic granular sludge as paper-coating biomaterials, bridging a critical knowledge gap in the sustainable use of biopolymers in industrial applications.

4.
Carbohydr Polym ; 331: 121842, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38388050

ABSTRACT

Chitosan has been extensively explored in food coatings. Still, its practical application is largely hampered by its conventional wet processing in acetic acid, whose residuals negatively impact food quality and safety. Here, we propose a new method to formulate chitosan coatings for food applications by avoiding organic acid processing and validate them on a cheese model. The procedure entails modifying a previously reported process based on HCl chitosan treatment and neutralising the resulting gel. The obtained chitosan is solubilised in water using carbonic acid that forms in situ by dissolving carbon dioxide gas. The reversibility of water carbonation allows for easy removal of carbonic acid residues, resulting in acid-free chitosan films and coatings. The performance of the coating was tested against state-of-the-art chitosan-based and polymeric coatings. We preliminarily characterised the films' properties (water stability, barrier, and optical properties). Then, we assessed the performance of the coating on Provolone cheese as a food model (mass transfer and texture profiles over 14 days). The work demonstrated the advantage of the proposed approach in solving some main issues of food quality and safety, paving the way for an effective application of chitosan in future food contact applications.


Subject(s)
Cheese , Chitosan , Chitosan/chemistry , Food Preservation/methods , Carbonic Acid , Water , Food Packaging/methods
5.
Soft Matter ; 19(41): 7869-7884, 2023 Oct 25.
Article in English | MEDLINE | ID: mdl-37817578

ABSTRACT

Methylcellulose (MC) hydrogels are ideal materials for the design of thermo-responsive platforms capable of exploiting the environment temperature as a driving force to activate their smart transition. However, MC hydrogels usually show reduced stability in an aqueous environment and low mechanical properties, limiting their applications' breadth. A possible approach intended to overcome these limitations is chemical crosslinking, which represents a simple yet effective strategy to modify the MC hydrogels' properties (e.g., physicochemical, mechanical, and biological). In this regard, understanding the selected crosslinking method's role in modulating the MC hydrogels' properties is a key factor in their design. This review offers a perspective on the main MC chemical crosslinking approaches reported in the literature. Three main categories can be distinguished: (i) small molecule crosslinkers, (ii) crosslinking by high-energy radiation, and (iii) crosslinking via MC chemical modification. The advantages and limitations of each approach are elucidated, and special consideration is paid to the thermo-responsive properties after crosslinking towards the development of MC hydrogels with enhanced physical stability and mechanical performance, preserving the thermo-responsive behavior.

6.
J Mater Sci Mater Med ; 34(1): 3, 2022 Dec 31.
Article in English | MEDLINE | ID: mdl-36586059

ABSTRACT

Cell microencapsulation has been utilized for years as a means of cell shielding from the external environment while facilitating the transport of gases, general metabolites, and secretory bioactive molecules at once. In this light, hydrogels may support the structural integrity and functionality of encapsulated biologics whereas ensuring cell viability and function and releasing potential therapeutic factors once in situ. In this work, we describe a straightforward strategy to fabricate silk fibroin (SF) microgels (µgels) and encapsulate cells into them. SF µgels (size ≈ 200 µm) were obtained through ultrasonication-induced gelation of SF in a water-oil emulsion phase. A thorough physicochemical (SEM analysis, and FT-IR) and mechanical (microindentation tests) characterization of SF µgels were carried out to assess their nanostructure, porosity, and stiffness. SF µgels were used to encapsulate and culture L929 and primary myoblasts. Interestingly, SF µgels showed a selective release of relatively small proteins (e.g., VEGF, molecular weight, MW = 40 kDa) by the encapsulated primary myoblasts, while bigger (macro)molecules (MW = 160 kDa) were hampered to diffusing through the µgels. This article provided the groundwork to expand the use of SF hydrogels into a versatile platform for encapsulating relevant cells able to release paracrine factors potentially regulating tissue and/or organ functions, thus promoting their regeneration.


Subject(s)
Fibroins , Microgels , Fibroins/chemistry , Cell Encapsulation , Spectroscopy, Fourier Transform Infrared , Hydrogels/chemistry , Silk
7.
Gels ; 8(5)2022 May 12.
Article in English | MEDLINE | ID: mdl-35621596

ABSTRACT

Infection is a severe complication in chronic wounds, often leading to morbidity or mortality. Current treatments rely on dressings, which frequently contain silver as a broad-spectrum antibacterial agent, although improper dosing can result in severe side effects. This work proposes a novel methylcellulose (MC)-based hydrogel designed for the topical release of silver nanoparticles (AgNPs) via an intelligent mechanism activated by the pH variations in infected wounds. A preliminary optimization of the physicochemical and rheological properties of MC hydrogels allowed defining the optimal processing conditions in terms of crosslinker (citric acid) concentration, crosslinking time, and temperature. MC/AgNPs nanocomposite hydrogels were obtained via an in situ synthesis process, exploiting MC both as a capping and reducing agent. AgNPs with a 12.2 ± 2.8 nm diameter were obtained. MC hydrogels showed a dependence of the swelling and degradation behavior on both pH and temperature and a noteworthy pH-triggered release of AgNPs (release ~10 times higher at pH 12 than pH 4). 1H-NMR analysis revealed the role of alkaline hydrolysis of the ester bonds (i.e., crosslinks) in governing the pH-responsive behavior. Overall, MC/AgNPs hydrogels represent an innovative platform for the pH-triggered release of AgNPs in an alkaline milieu.

8.
Gels ; 7(3)2021 Sep 14.
Article in English | MEDLINE | ID: mdl-34563027

ABSTRACT

Methylcellulose (MC) hydrogels have been successfully proposed in the field of cell sheet engineering (CSE), allowing cell detachment from their surface by lowering the temperature below their transition temperature (Tt). Among the main limitations of pristine MC hydrogels, low physical stability and mechanical performances limit the breadth of their potential applications. In this study, a crosslinking strategy based on citric acid (CA) was used to prepare thermoresponsive MC hydrogels, with different degrees of crosslinking, to exploit their possible use as substrates in CSE. The investigated amounts of CA did not cause any cytotoxic effect while improving the mechanical performance of the hydrogels (+11-fold increase in E, compared to control MC). The possibility to obtain cell sheets (CSs) was then demonstrated using murine fibroblast cell line (L929 cells). Cells adhered on crosslinked MC hydrogels' surface in standard culture conditions and then were harvested at selected time points as single CSs. CS detachment was achieved simply by lowering the external temperature below the Tt of MC. The detached CSs displayed adhesive and proliferative activity when transferred to new plastic culture surfaces, indicating a high potential for regenerative purposes.

9.
Soft Matter ; 17(21): 5284-5302, 2021 Jun 02.
Article in English | MEDLINE | ID: mdl-34075927

ABSTRACT

Given the intertwined physicochemical effects exerted in vivo by both natural and synthetic (e.g., biomaterial) interfaces on adhering cells, the evaluation of structure-function relationships governing cellular response to micro-engineered surfaces for applications in neuronal tissue engineering requires the use of in vitro testing platforms which consist of a clinically translatable material with tunable physiochemical properties. In this work, we micro-engineered chitosan substrates with arrays of parallel channels with variable width (20 and 60 µm). A citric acid (CA)-based crosslinking approach was used to provide an additional level of synergistic cueing on adhering cells by regulating the chitosan substrate's stiffness. Morphological and physicochemical characterization was conducted to unveil the structure-function relationships which govern the activity of rat dorsal root ganglion neurons (DRGs) and human mesenchymal stem cells (hMSCs), ultimately singling out the key role of microtopography, roughness and substrate's stiffness. While substrate's stiffness predominantly affected hMSC spreading, the modulation of the channels' design affected the neuronal architecture's complexity and guided the morphological transition of hMSCs. Finally, the combined analysis of tubulin expression and cell morphology allowed us to cast new light on the predominant role of the microtopography over substrate's stiffness in the process of hMSCs neurogenic differentiation.


Subject(s)
Chitosan , Mesenchymal Stem Cells , Animals , Cell Differentiation , Cells, Cultured , Ganglia, Spinal , Humans , Neurons , Rats
10.
Langmuir ; 37(14): 4072-4081, 2021 Apr 13.
Article in English | MEDLINE | ID: mdl-33797907

ABSTRACT

The achievement of a homogeneous dispersion of nanoparticles is of paramount importance in supporting their technological application. In wet processing, stable dispersions were largely obtained via surfactant or surface functionalization: although effective, the use of dispersant can alter, or even impair, the functional properties of the resulting nanostructured systems. Herein, we report a novel integrated modeling and experimental approach to obtain stable ZrO2 nanoparticle (NP) dispersions at native dimensions (about 5 nm) in homogeneous ternary mixtures of solvents (i.e., water, ethanol, and 1,2-dichlorobenzene) without any further surface functionalization. A miscibility ternary diagram was computed exploiting the universal quasi-chemical functional-group activity coefficient (UNIFAC) model, which was then experimentally validated. Dynamic light scattering (DLS) on these mixtures highlights that nanometric structures, resembling nanoemulsion droplets, form close to the mixture two-phase boundary, with a size that depends on the ternary mixture composition. ZrO2-NPs were then synthesized following a classic sol-gel approach and characterized by XRD and Raman spectroscopy. ZrO2-NPs were dispersed in HCl and mixed with different mixtures of ethanol and 1,2-dichlorobenzene (DCB), obtaining homogeneous and stable dispersions. These dispersions were then studied by means of DLS as a function of DCB concentration, observing that the nanoparticles can be dispersed at their native dimensions when the mass fraction of DCB was lower than 60%, whereas the increase of the hydrophobic solvent leads to the NPs' agglomeration and sedimentation. The proposed approach not only offers specific guidelines for the design of ZrO2-NPs dispersions in a ternary solvent mixture but can also be extended to other complex solvent mixtures in order to achieve stable dispersions of nanoparticles with no functionalization.

11.
Biomed Mater ; 16(4)2021 04 30.
Article in English | MEDLINE | ID: mdl-33857927

ABSTRACT

Cytocompatible bioactive surface treatments conferring antibacterial properties to osseointegrated dental implants are highly requested to prevent bacteria-related peri-implantitis. Here we focus on a newly designed family of mesoporous coatings based on zirconia (ZrO2) microstructure doped with gallium (Ga), exploiting its antibacterial and pro-osseo-integrative properties. The ZrO2films were obtained via sol-gel synthesis route using Pluronic F127 as templating agent, while Ga doping was gained by introducing gallium nitrate hydrate. Chemical characterization by means of x-ray photoelectron spectroscopy and glow discharge optical emission spectroscopy confirmed the effective incorporation of Ga. Then, coatings morphological and structural analysis were carried out by transmission electron microscopy and selected area electron diffraction unveiling an effective stabilization of both the mesoporous structure and the tetragonal ZrO2phase. Specimens' cytocompatibility was confirmed towards gingival fibroblast and osteoblasts progenitors cultivated directly onto the coatings showing comparable metabolic activity and morphology in respect to controls cultivated on polystyrene. The presence of Ga significantly reduced the metabolic activity of the adhered oral pathogensPorphyromonas gingivalisandAggregatibacter actinomycetemcomitansin comparison to untreated bulk zirconia (p< 0.05); on the opposite, Ga ions did not significantly reduce the metabolism of the oral commensalStreptococcus salivarius(p> 0.05) thus suggesting for a selective anti-pathogens activity. Finally, the coatings' ability to preserve cells from bacterial infection was proved in a co-culture method where cells and bacteria were cultivated in the same environment: the presence of Ga determined a significant reduction of the bacteria viability while allowing at the same time for cells proliferation. In conclusion, the here developed coatings not only demonstrated to satisfy the requested antibacterial and cytocompatibility properties, but also being promising candidates for the improvement of implantable devices in the field of implant dentistry.


Subject(s)
Anti-Bacterial Agents , Biofilms/drug effects , Coated Materials, Biocompatible , Dental Implants , Zirconium , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Bacteria/drug effects , Cells, Cultured , Coated Materials, Biocompatible/chemistry , Coated Materials, Biocompatible/pharmacology , Coculture Techniques , Fibroblasts/cytology , Gallium , Gingiva/cytology , Humans , Osteoblasts/cytology , Surface Properties , Zirconium/chemistry , Zirconium/pharmacology
12.
Tissue Eng Part B Rev ; 27(5): 486-513, 2021 10.
Article in English | MEDLINE | ID: mdl-33115329

ABSTRACT

Methylcellulose (MC) is an attractive material used to produce thermo-responsive hydrogels. They undergo sol-gel transition when a critical temperature is reached, thus modifying their properties (e.g., physicochemical and mechanical) in response to temperature changes. This behavior is particularly attractive when the body temperature acts as a trigger to modulate the thermo-responsive behavior of MC hydrogels. In this regard, exciting advances have been achieved in the field of cell and drug delivery, tissue engineering, and regenerative medicine, making MC a very attractive and versatile biomaterial. This review aims to present MC hydrogels, examining their preparation, physical properties, and tunability of thermal response, lastly moving to a comprehensive depiction of both their conventional and innovative applications for tissue regeneration purposes. In particular, three main families of applications are introduced: (1) in situ gelling systems, which undergo sol-gel transition upon delivery into a target site (e.g., tissue or organ), assisting the regeneration of the latter both in the presence or absence of loading components (e.g., cells, biomolecules, and inorganic materials); (2) three-dimensional (3D) (bio)printing, where the sol-gel transition is induced by heating MC-based (bio)inks after printing, obtaining 3D tissue-engineered substitutes with defined geometries and high shape fidelity; (3) smart culture surfaces, where the hydrophilic/hydrophobic transition of MC is exploited to reach a selective attachment/detachment of cells, offering the possibility to obtain cell sheets and cell bodies for tissue reconstruction without the need of any proteolytic enzyme. The main limitations of MC hydrogels will be then examined, together with current solutions to overcome them. Moreover, an overview of the future directions in the field of MC smart hydrogels will be given, with particular focus on the design of multiresponsive systems capable to respond to multiple stimuli (e.g., chemical and biological stimuli), toward the development of more patient-specific treatments. Finally, an overview of the patents and clinical trials describing the use of MC will be given, retracing the abovementioned families of application.


Subject(s)
Hydrogels , Methylcellulose , Biocompatible Materials , Humans
13.
J Mater Sci Mater Med ; 31(5): 43, 2020 May 01.
Article in English | MEDLINE | ID: mdl-32358696

ABSTRACT

Bioactive glasses (BGs), due to their ability to influence osteogenic cell functions, have become attractive materials to improve loaded and unloaded bone regeneration. BG systems can be easily doped with several metallic ions (e.g., Ag, Sr, Cu, Nb) in order to confer antibacterial properties. In particular, Nb, when compared with other metal ions, has been reported to be less cytotoxic and possess the ability to enhance mineralization process in human osteoblast populations. In this study, we co-deposited, through one-pot electrophoretic deposition (EPD), chitosan (CS), gelatin (GE) and a modified BG containing Nb to obtain substrates with antibacterial activity for unloaded bone regeneration. Self-standing composite scaffolds, with a defined porosity (15-90 µm) and homogeneous dispersion of BGs were obtained. TGA analysis revealed a BG loading of about 10% in the obtained scaffolds. The apatite formation ability of the scaffolds was evaluated in vitro in simulated body fluid (SBF). SEM observations, XRD and FT-IR spectra showed a slow (21-28 days) yet effective nucleation of CaP species on BGs. In particular, FT-IR peak around 603 cm-1 and XRD peak at 2θ = 32°, denoted the formation of a mineral phase after SBF immersion. In vitro biological investigation revealed that the release of Nb from composite scaffolds had no cytotoxic effects. Interestingly, BG-doped Nb scaffolds displayed antibacterial properties, reducing S. lutea and E. coli growth of ≈60% and ≈50%, respectively. Altogether, the obtained results disclose the produced composite scaffolds as promising materials with inherent antibacterial activity for bone tissue engineering applications.


Subject(s)
Bone Regeneration/physiology , Ceramics/chemistry , Chitosan/chemistry , Glass/chemistry , Niobium/chemistry , Biocompatible Materials , Cell Line, Tumor , Electrophoresis , Gelatin , Humans , Hydrogen-Ion Concentration , Materials Testing , Microscopy, Electron, Scanning , Osteosarcoma , Spectroscopy, Fourier Transform Infrared , Tissue Scaffolds
14.
Soft Matter ; 16(24): 5577-5587, 2020 Jun 24.
Article in English | MEDLINE | ID: mdl-32406462

ABSTRACT

Methylcellulose (MC) hydrogels, undergoing sol-gel reversible transition upon temperature changes, lend themselves to smart system applications. However, their reduced stability in aqueous environment and unsatisfactory mechanical properties limit the breadth of their possible applications. Here, a crosslinking strategy based on citric acid (CA) was developed: exploiting three crosslinking parameters (CA concentration, crosslinking time, and crosslinking temperature) by a design of experiment approach, optimized crosslinked MC hydrogels (MC-L, MC-M, MC-H) were obtained and characterized. Swelling tests in water revealed the effectiveness of CA crosslinking in modulating the water uptake of MC hydrogels. Both theoretical and experimental analyses showed an increase in the crosslinking density by the rationale selection of process parameters. The extent of sol-gel transition was assessed by swelling tests, Raman spectroscopy and rheological analyses. MC-M samples demonstrated to preserve their thermo-responsive behavior around their lower critical solution temperature (LCST), while showing increased stability and enhanced mechanical properties when compared to pristine MC hydrogels.

15.
Materials (Basel) ; 12(9)2019 May 07.
Article in English | MEDLINE | ID: mdl-31067821

ABSTRACT

Bioactive glasses (BG) possess significant bone-bonding and osteogenic properties that support their use for bone defects repair in orthopaedic and dental procedures. Recent advancement enables the manufacturing of BG-based scaffolds providing structural support during bone regeneration. Despite the wide number of studies on BG and BG-based materials, little information on their aging mechanisms and shelf life is available in the literature. In this study, the evolution of chemical species on BG-based foams was investigated via accelerated tests in the presence of CO2 and humidity. The aging process led to the formation of carbonates (Na2CO3 and CaCO3) and hydrocarbonates (NaHCO3). The amount and composition of nucleated species evolved with time, affecting the structure, properties, and bioactivity of the scaffolds. This study provides a first structured report of aging effects on the structure and chemico-physical properties of bioactive glass-based scaffolds, offering an insight about the importance of their storage and packaging.

16.
J Mater Sci Mater Med ; 30(4): 40, 2019 Mar 27.
Article in English | MEDLINE | ID: mdl-30919137

ABSTRACT

Clobetasol propionate (CP) is a high-potency corticosteroid, representing the standard of care for the symptomatic treatment of different skin disorders as well as oral mucosal diseases. Several topical delivery systems are available for treating oral lesions, but the ideal one is still lacking. In this work, we propose a novel class of chitosan (CS) patches, loaded with CP, for the topical treatment of inflammatory chronic oral diseases. Chitosan patches have been fabricated via electrophoretic deposition (EPD), by using a one-pot approach in order to load controlled quantity of CP. Optimized structures showed a water uptake in the range of 200-360% and mechanical properties that allow the design of flexible patches in wet state (E = 0.6 MPa and σbr = 0.55 MPa). Ultraviolet-visible (UV-Vis) spectroscopy was used for the evaluation of both loading and release profile of CP in CS patches. The CP loading has been tuned by adjusting CP concentration in deposition bath-in the range 0.002-0.12 mg cm-2-while releasing curves show an in vitro CP burst of about 80% in the first two hours. Overall, the obtained properties paved the way for the application of this new class of patches for the local oral release of CP.


Subject(s)
Chitosan/chemistry , Chitosan/pharmacokinetics , Clobetasol/administration & dosage , Drug Delivery Systems , Electrophoresis , Transdermal Patch , Administration, Topical , Clobetasol/pharmacokinetics , Delayed-Action Preparations , Drug Carriers , Drug Compounding/methods , Drug Liberation , Electrophoresis/methods , Equipment Design/methods , Ethanol/pharmacokinetics , Humans , Skin/drug effects , Skin/metabolism , Skin Diseases/drug therapy , Water/metabolism , Wettability
17.
J Biomed Mater Res A ; 107(7): 1455-1465, 2019 07.
Article in English | MEDLINE | ID: mdl-30786159

ABSTRACT

One of the main challenges in the design of scaffolds for cortical bone regeneration is mimicking the highly oriented, hierarchical structure of the native tissue in an efficient, simple, and consistent way. As a possible solution to this challenge, positive replica based on electrophoretic deposition (EPD) was here evaluated as a technique to produce organic/inorganic scaffolds with oriented micro-porosities mimicking Haversian canals diameter and spacing. Two different sizes of 45S5 bioactive glass (BG) powders were chosen as inclusions and loaded in a chitosan matrix via EPD on micro-patterned cathodes. Self-standing chitosan scaffolds, with a homogeneous dispersion of BG particles and regularly-oriented micro-channels (ϕ = 380 ± 50 µm, inter-channel spacing = 600 ± 40 µm), were obtained. In vitro analysis in simulated body fluid (SBF) revealed the ability to induce a deposition of a homogenous layer of hydroxyapatite (HA), with Ca/P nucleation reactions appearing kinetically favored by smaller BG particles. Cell interaction with hybrid scaffolds was evaluated in vitro with bone osteosarcoma cells (SAOS-2). The osteoconductive potential of EPD structures was assessed by evaluating cells proliferation, viability and scaffold colonization. Results indicate that EPD is a simple yet extremely effective technique to prepare composite micro-patterned structures and can represent a platform for the development of a new generation of bone scaffolds. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2019.


Subject(s)
Ceramics/chemistry , Chitosan/chemistry , Glass/chemistry , Tissue Scaffolds/chemistry , Body Fluids/chemistry , Cell Line, Tumor , Cell Survival , DNA/metabolism , Electrophoresis , Humans , Thermogravimetry , X-Ray Diffraction
18.
Int J Artif Organs ; 41(6): 337-359, 2018 Jun.
Article in English | MEDLINE | ID: mdl-29614899

ABSTRACT

Advances in regenerative medicine and in modern biomedical therapies are fast evolving and set goals causing an upheaval in the field of materials science. This review discusses recent developments involving the use of biopolymers as smart materials, in terms of material properties and stimulus-responsive behavior, in the presence of environmental physico-chemical changes. An overview on the transformations that can be triggered in natural-based polymeric systems (sol-gel transition, polymer relaxation, cross-linking, and swelling) is presented, with specific focus on the benefits these materials can provide in biomedical applications.


Subject(s)
Artificial Organs , Biopolymers , Equipment Design , Humans , Regenerative Medicine
19.
Biomed Mater ; 11(2): 025018, 2016 Apr 21.
Article in English | MEDLINE | ID: mdl-27099204

ABSTRACT

Neo-vascularization is a key factor in tissue regeneration within porous scaffolds. Here, we tested the hypothesis that micro-patterned scaffolds, with precisely-designed, open micro-channels, might help endothelial cells to produce intra-scaffold vascular networks. Three series of micro-patterned scaffolds were produced via electrochemical replica-deposition of chitosan and cross-linking. All had regularly-oriented micro-channels (ϕ 500 µm), which differed for the inter-channel spacing, at 600, 700, or 900 µm, respectively. Random-pore scaffolds, using the same technique, were taken as controls. Physical-mechanical characterization revealed high water uptake and favorable elastic mechanical behavior for all scaffolds, slightly reduced in the presence of cross-linking and enhanced with the 700 µm-spaced micro-pattern. At MTT assay, mouse endothelial cell viability was >90% at day 1, 3 and 7, confirmed by visual examination with scanning electron microscopy (SEM). Intra-scaffold cell density, at fluorescence analysis, was higher for the 600 µm-spaced and the 700 µm-spaced micro-patterns over the others. The 700 µm-spaced scaffold was selected for the in vivo testing, to be compared to the random-pore one. Neither type produced an inflammatory reaction; both showed excellent tissue ingrowth. Micro-patterned scaffolds enhanced neo-vascularization, demonstrated by immunofluorescent, semi-quantitative analyses. These findings support the use of micro-patterned porous scaffolds, with adequately spaced micro-channels, to promote neo-vascularization.


Subject(s)
Neovascularization, Physiologic , Tissue Scaffolds/chemistry , Animals , Biocompatible Materials/adverse effects , Biocompatible Materials/chemistry , Cell Count , Cell Proliferation , Cell Survival , Chitosan/adverse effects , Chitosan/chemistry , Chitosan/immunology , Cross-Linking Reagents , Electrochemical Techniques/methods , Endothelial Cells/cytology , Endothelial Cells/physiology , Female , Male , Materials Testing , Mice , Mice, Inbred C57BL , Microscopy, Electron, Scanning , Microtechnology/methods , Porosity , Regeneration/physiology , Tissue Scaffolds/adverse effects
20.
Biomed Mater ; 11(1): 015005, 2016 Feb 02.
Article in English | MEDLINE | ID: mdl-26836444

ABSTRACT

Large bone defects are challenging to heal, and often require an osteoconductive and stable support to help the repair of damaged tissue. Bioglass-based scaffolds are particularly promising for this purpose due to their ability to stimulate bone regeneration. However, processing technologies adopted so far do not allow for the synthesis of scaffolds with suitable mechanical properties. Also, conventional sintering processes result in glass de-vitrification, which generates concerns about bioactivity. In this work, we studied the bioactivity and the mechanical properties of Bioglass(®) based scaffolds, produced via a powder technology inspired process. The scaffolds showed compressive strengths in the range of 5-40 MPa, i.e. in the upper range of values reported so far for these materials, had tunable porosity, in the range between 55 and 77%, and pore sizes that are optimal for bone tissue regeneration (100-500 µm). We immersed the scaffolds in simulated body fluid (SBF) for 28 d and analyzed the evolution of the scaffold mechanical properties and microstructure. Even if, after sintering, partial de-vitrification occurred, immersion in SBF caused ion release and the formation of a Ca-P coating within 2 d, which reached a thickness of 10-15 µm after 28 d. This coating contained both hydroxyapatite and an amorphous background, indicating microstructural amorphization of the base material. Scaffolds retained a good compressive strength and structural integrity also after 28 d of immersion (6 MPa compressive strength). The decrease in mechanical properties was mainly related to the increase in porosity, caused by its dissolution, rather than to the amorphization process and the formation of a Ca-P coating. These results suggest that Bioglass(®) based scaffolds produced via powder metallurgy-inspired technique are excellent candidates for bone regeneration applications.


Subject(s)
Bone Substitutes/chemical synthesis , Ceramics/chemistry , Glass/chemistry , Tissue Scaffolds , Compressive Strength , Elastic Modulus , Equipment Design , Equipment Failure Analysis , Hardness , Heating/methods , Materials Testing , Metallurgy/methods , Powders , Stress, Mechanical , Tensile Strength
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