Degradation In PBS Research Articles

Evaluation of the effects of decellularized extracellular matrix nanoparticles incorporation on the polyhydroxybutyrate/nano chitosan electrospun scaffold for cartilage tissue engineering

Recent research focuses on fabricating scaffolds imitating the extracellular matrix (ECM) in texture, composition, and functionality. Moreover, specific nano-bio-particles can enhance cell differentiation. Decellularized ECM nanoparticles possess all of the mentioned properties. In this research, cartilage ECM, extracted from the cow's femur condyle, was decellularized, and ECM nanoparticles were synthesized. Finally, nanocomposite electrospun fibers containing polyhydroxybutyrate (PHB), chitosan (Cs) nanoparticles, and ECM nanoparticles were fabricated and characterized. TEM and DLS results revealed ECM nanoparticle sizes of 17.51 and 21.6 nm, respectively. Optimal performance was observed in the scaffold with 0.75 wt% ECM nanoparticles (PHB-Cs/0.75E). By adding 0.75 wt% ECM, the ultimate tensile strength and elongation at break increased by about 29 % and 21 %, respectively, while the water contact angle and crystallinity decreased by about 36° and 2 %, respectively. Uneven and rougher surfaces of the PHB-Cs/0.75E were determined by FESEM and AFM images, respectively. TEM images verified the uniform dispersion of nanoparticles within the fibers. After 70 days of degradation in PBS, the PHB-Cs/0.75E and PHB-Cs scaffolds demonstrated insignificant weight loss differences. Eventually, enhanced viability, attachment, and proliferation of the human costal chondrocytes on the PHB-Cs/0.75E scaffold, concluded from MTT, SEM, and DAPI staining, confirmed its potential for cartilage tissue engineering.

Hydrolytic degradation of polylactide/polybutylene succinate blends with bioactive glass

Polylactides (PLAs) have been vastly studied for biomedical engineering applications, but their rigidness limits their use. Blending them with more flexible polymers, such as polybutylene succinate (PBSu), results in softer materials, expanding the range of possible applications. However, the biopolymers lack bioactivity, which can be overcome by adding bioactive glass. Combining the inorganic phase with the organic phase (especially with blends) results in a complex material. Therefore, understanding the hydrolytic degradation of each component is crucial. In this context, we report on processing polylactide and polybutylene succinate (PLA/PBSu) blends and their composites (30 wt% of bioactive glass 13‐93, BaG). The impact of blending and compounding with BaG on the final product's molecular weight and mechanical properties and the BaG dispersion in the polymer matrices was assessed. In addition, in vitro degradation in PBS was studied. While the degradation of the polymer was assessed by GPC, the BaG dissolution was quantified by ICP-OES. Blending decreased the initial mechanical properties and molecular weight, and compounding with BaG further decreased the initial mechanical properties. During the immersion in PBS, blending accelerated the loss of mechanical properties and molecular weight, while BaG accelerated the degradation of PLA-containing materials but had little effect on PBSu. Blending and compounding with BaG enabled us to produce materials with a wide range of mechanical properties: bending strength of 34–125 MPa, shear strength of 22–47 MPa and bending modulus of 1.1–3.9 GPa. The selection of tailorable properties of these polymer/BaG composites enables their application for tissue engineering of bone to soft tissue.

Evaluation of the effects of zein incorporation on physical, mechanical, and biological properties of polyhydroxybutyrate electrospun scaffold for bone tissue engineering applications

Materials and fabrication methods significantly influence the scaffold's final features in tissue engineering. This study aimed to blend zein with polyhydroxybutyrate (PHB) at 5, 10, and 15 wt%, fabricate scaffolds using electrospinning, and then characterize them. SEM and mechanical analyses identified the scaffold with 10 wt% zein (PHB-10Z) as the optimal sample. Incorporating 10 wt% zein reduced fiber diameter from 894 ± 122 to 531 ± 42 nm while increasing ultimate tensile strength and elongation at break by approximately 53 % and 70 %, respectively. FTIR proved zein's presence in the scaffolds and possible hydrogen bonding with PHB. TGA confirmed the miscibility of polymers. DSC and XRD analyses indicated lower crystallinity for the PHB-10Z than for PHB. AFM evaluation indicated a rougher surface for the PHB-10Z in comparison to PHB. The PHB-10Z demonstrated a more hydrophobic surface and less weight loss after 100 days of degradation in PBS than PHB. The free radical scavenging assay exhibited antioxidant activity for the zein-containing scaffold. Eventually, enhanced cell attachment, viability, and differentiation in the PHB-10Z scaffold drawn from SEM, MTT, ALP activity, and Alizarin red staining of MG-63 cells confirmed that PHB-zein electrospun scaffold is a potent candidate for bone tissue engineering applications.

2D Collagen Membranes from Marine Demosponge Chondrosia reniformis (Nardo, 1847) for Skin-Regenerative Medicine Applications: An In Vitro Evaluation.

Research in tissue engineering and regenerative medicine has an ever-increasing need for innovative biomaterials suitable for the production of wound-dressing devices and artificial skin-like substitutes. Marine collagen is one of the most promising biomaterials for the production of such devices. In this study, for the first time, 2D collagen membranes (2D-CMs) created from the extracellular matrix extract of the marine demosponge Chondrosia reniformis have been evaluated in vitro as possible tools for wound healing. Fibrillar collagen was extracted from a pool of fresh animals and used for the creation of 2D-CMs, in which permeability to water, proteins, and bacteria, and cellular response in the L929 fibroblast cell line were evaluated. The biodegradability of the 2D-CMs was also assessed by following their degradation in PBS and collagenase solutions for up to 21 days. Results showed that C. reniformis-derived membranes avoided liquid and protein loss in the regeneration region and also functioned as a strong barrier against bacteria infiltration into a wound. Gene expression analyses on fibroblasts stated that their interaction with 2D-CMs is able to improve fibronectin production without interfering with the regular extracellular matrix remodeling processes. These findings, combined with the high extraction yield of fibrillar collagen obtained from C. reniformis with a solvent-free approach, underline how important further studies on the aquaculture of this sponge could be for the sustainable production and biotechnological exploitation of this potentially promising and peculiar biopolymer of marine origin.

Partial sulfation of gellan gum produces cytocompatible, body temperature-responsive hydrogels

Gellan gum (GG) is a biodegradable polysaccharide and forms thermosensitive hydrogels by a helix-mediated mechanism. Unfortunately, the wide use of GG in tissue engineering has been restricted due to its dramatically higher gelation temperature than normal body temperature. Here, we show that partial sulfation of GG affords a cytocompatible body temperature-responsive hydrogel with an interesting thermoreversibility at 42 °C. The partial sulfation of GG was confirmed by FTIR, EDX and elemental analyses. The sulfated GGs (SGGs) had a higher swelling ratio and degradation in PBS compared to the neat GG. Based on the results of rheometry analysis, the SGG with a degree of sulfation of 0.27 (H3 sample) showed a gelation temperature close to the physiological temperature. In addition, the drop in mechanical properties of SGGs was compensated by a further calcium-mediated ionic crosslinking, where Young's modulus of H3 increased from 10.6 ± 1.9 kPa up to 38.4 ± 5.5 kPa. Finally, we showed that the partial sulfation reaction of GG is a simple and mild strategy to modify chemical structure of GG, and to produce a cytocompatible, body temperature-responsive hydrogel compared to other modifying reactions such as oxidation reaction.

A Tribological Investigation of the Titanium Oxide and Calcium Phosphate Coating Electrochemical Deposited on Titanium

Titanium (Ti) and its alloys are widely used in biomedical applications due to their excellent mechanical properties and biocompatibility. However, they are a concern due to the possibility of cytotoxic effects coming from the degradation products. This degradation occurs by the combined action of corrosion and mechanical wear of these materials, which are released in the biological environment by the biomaterial implanted. The present article aims to investigate a new route to improve electrochemical and tribological performance with surface modification. Regarding the deposition of a protective layer on the surface, it consists of titanium oxide (TiO2) and calcium phosphate (CaP). Both coatings were performed by chronoamperometric methods with titanium oxidation at 1 V and calcium phosphate reduction at −1.5 V. The corrosion and tribocorrosion tests demonstrated the effective combination of TiO2 and CaP layer to protect the Ti substrate. Furthermore, this coating combination reduced corrosion degradation and mechanical wear in PBS, simulating a physiological environment. Additionally, it was observed that this combination of coating decreased the dissipated energy, and consequently, the wear decreased during sliding tests. All these findings indicate the protective behavior of the TiO2 and CaP layer during the tribocorrosion tests.

Electrospun Magnetic Composite Poly-3-hydroxybutyrate/Magnetite Scaffolds for Biomedical Applications: Composition, Structure, Magnetic Properties, and Biological Performance.

Magnetically responsive composite polymer scaffolds have good potential for a variety of biomedical applications. In this work, electrospun composite scaffolds made of polyhydroxybutyrate (PHB) and magnetite (Fe3O4) particles (MPs) were studied before and after degradation in either PBS or a lipase solution. MPs of different sizes with high saturation magnetization were synthesized by the coprecipitation method followed by coating with citric acid (CA). Nanosized MPs were prone to magnetite-maghemite phase transformation during scaffold fabrication, as revealed by Raman spectroscopy; however, for CA-functionalized nanoparticles, the main phase was found to be magnetite, with some traces of maghemite. Submicron MPs were resistant to the magnetite-maghemite phase transformation. MPs did not significantly affect the morphology and diameter of PHB fibers. The scaffolds containing CA-coated MPs lost 0.3 or 0.2% of mass in the lipase solution and PBS, respectively, whereas scaffolds doped with unmodified MPs showed no mass changes after 1 month of incubation in either medium. In all electrospun scaffolds, no alterations of the fiber morphology were observed. Possible mechanisms of the crystalline-lamellar-structure changes in hybrid PHB/Fe3O4 scaffolds during hydrolytic and enzymatic degradation are proposed. It was revealed that particle size and particle surface functionalization affect the mechanical properties of the hybrid scaffolds. The addition of unmodified MPs increased scaffolds' ultimate strength but reduced elongation at break after the biodegradation, whereas simultaneous increases in both parameters were observed for composite scaffolds doped with CA-coated MPs. The highest saturation magnetization─higher than that published in the literature─was registered for composite PHB scaffolds doped with submicron MPs. All PHB scaffolds proved to be biocompatible, and the ones doped with nanosized MPs yielded faster proliferation of rat mesenchymal stem cells. In addition, all electrospun scaffolds were able to support angiogenesis in vivo at 30 days after implantation in Wistar rats.

An investigation of the hydrophilicity, biocompatibility and biodegradability properties of BT/HA/PHBV micro-nanofibers composite film

BT/HA composite nanoparticles with particle size of about 50–100 nm were fabricated by hydrothermal process at 160 °C for 12 h, and BT/HA/PHBV micro-nanofibers film with nanofibers diameter about 500 nm–1 μm were prepared by electrospinning method. The micro-nanofibers film infiltrate and spread quickly, with a wetting angle of 0°, which showed good hydrophilicity. The micro-nanofibers film has good biological activity, osteogenic ability in SBF, and obvious degradation in PBS. Moreover, the biotoxicity of composites shows that the BT/HA/PHBV micro-nanofibers film is non-toxic to the MSCs cells. In summary, the BT/HA/PHBV micro-nanofibers film prepared in this paper has excellent bioactivity and biodegradability, which is a good choice for bone tissue engineering scaffold materials and broad application in biomaterials prospects.

A Carbodiimide Cross‐Linked Silk Fibroin/Sodium Alginate Composite Hydrogel with Tunable Properties for Sustained Drug Delivery

AbstractCarbodiimide cross‐linked silk fibroin (SF)/sodium alginate (SA) composite hydrogels with superior stability and tunable properties are developed by varying preparation parameters. SF/SA blend ratio modulation allows to achieve composite hydrogel gelation times of 18–65 min, and rheological analysis shows that the speed of gel formation, the hydrogel network's density, and the hydrogels’ compressive properties are closely related to the blend ratio. The G′ of different hydrogels varies substantially from 28 to 413 Pa, and the hydrogel with higher SF content has a greater stiffness. The composite hydrogels present appropriate porosity of 76.63–85.09% and pore size of 316–603 µm. Hydrogel stability improves significantly after cross‐linking, and substantial swelling occurs due to the hydrophilicity of SA. The 7/3 and 6/4 SF/SA hydrogels are more resistant to degradation in PBS, and cytotoxicity testing confirmed their biocompatibility. For release studies in vitro, two model compounds are used as drug models, tetracycline hydrochloride, and bovine serum albumin (BSA). Different ratios of SF/SA have a greater influence on the release of BSA. This study provides a practical preparation method for flexible SF/SA composite hydrogels, which can help design hydrogels with specific physicochemical properties for different applications, especially drug delivery.

Investigation and comparison of new galactosylation methods on PCL/chitosan scaffolds for enhanced liver tissue engineering

In liver tissue engineering, improving the ability of the scaffold to increase the tendency of cells to grow and proliferate is very important. In this study, new methods for modifying the surface of Polycaprolactone (PCL)/Chitosan (Cs) nanofiber for use in liver tissue engineering have been proposed. Galactosylation of chitosan was performed in three ways. According to the FE-SEM, FTIR, NMR and DSC analysis, presence of galactose in uniform nanofibers confirmed and led to a decrease in crystallinity. The hydrophobicity of the scaffolds by contact angle showed that the scaffold with galactosylated after electrospinning, had the highest contact angle of 82.22 ± 2° compared to raw scaffold with 98.52 ± 4°. According to the results of degradation in PBS, the highest rate of degradation was observed in scaffolds that were galactosylated after electrospinning. By culturing HepG2 cells on and based on the results of SEM and MTT analysis, found that the presence of galactose in the scaffolds significantly increased cell growth and proliferation without any toxicity. The immersion method shows a greater ability to improve the growth of liver cells. Also, using in-situ way due to the roughness created in this method may lead to better results especially for in-vivo tests.

Regenerated cellulose nanofibers from cellulose acetate: Incorporating hydroxyapatite (HAp) and silver (Ag) nanoparticles (NPs), as a scaffold for tissue engineering applications

Cellulose nanofibers, which are troublesome to spin into fibers, can be easily fabricated by post-regeneration of its acetate-derived threads. Cellulose is a natural polymer; it enjoys better biocompatibility, cellular mimicking, and hydrophilic properties than its proportionate analog. Herein, we regenerated acetate-free nanofibers by alkaline de-acetylation of as-spun nanofibers. The resultant cellulose nanofibers previously loaded with hydroxyapatite (HAp) were immobilized using silver (Ag) nanoparticles (NPs) by reduction of adsorbed Ag ions on using sodium borohydride. These amalgamated nanofibers were characterized for SEM, EDX, TEM, FTIR, and hydrophilicity tests revealing the existence of both HAp and Ag NPs in/on the nanofiber scaffolds. The de-acetylation of composite nanofibers resulted in spontaneous hydrophilicity. These nanofibers were cytocompatible, as resolved by MTT assay conducted on chicken embryo fibroblasts. The SEM of the samples after cell culture revealed that these composites allowed a proliferation of the fibroblasts over and within the nanofiber network, and increased concentration of HAp levitated the excessive of apatite formation as well as increased cell growth. The antimicrobial activity of these nanofibers was assessed on E. coli (BL21) and S. aureus, suggesting the potential of de-acetylated nanofibers to restrain bacterial growth. The degradation study for 10, 30, and 60 days indicated degradation of the fibers much is faster in enzymes as compared to degradation in PBS. The results certify that these nanofibers possess enormous potential for soft and hard tissue engineering besides their antimicrobial properties.

A comparative study on agarose acetate and PDLLA scaffold for rabbit femur defect regeneration

The development of degradable polymer scaffolds is a key issue in bone regeneration. Poly(D, L-lactide) (PDLLA) and its derivatives have usually been applied to the construction of degradable scaffolds, but these scaffolds had problems with acidic degradation products and quick loss of mechanic strength during the later degradation, which usually led to scaffold collapse and cavity formation because of the slower rate of bone regeneration. In the present paper, a polysaccharide derivative, agarose acetate (AGA), was synthesized and a novel porous AGA scaffold was successfully developed through a salt-leaching process. The AGA scaffold had over 90% porosity without swelling in water, and compared to collapse and acidic products of PDLLA scaffold during degradation, the AGA scaffold maintained a stable morphology and a nearly neutral pH value over 18 months’ degradation in PBS. A bone mesenchymal stem cells (BMSCs) adhesion and proliferation experiment showed that more cells adhered to the AGA scaffold than to the PDLLA scaffold. A subcutaneous implant test showed that the AGA scaffold slowly degraded and did not cause an inflammatory response surrounding the implantation lesion site. AGA scaffold was implanted into femur defects in New Zealand white rabbits to test its in vivo performance. Results indicated that the AGA scaffold accelerated the process of bone regeneration compared to the PDLLA group and, with time, new bone was formed from the margin toward the center of the scaffolds, and the scaffold left in place retained its porous structure without collapsing. Meanwhile, the AGA scaffold showed a low degradation rate and kept its shape during the in vivo degradation compared to the PDLLA scaffold. This performance could have the benefit of integrated regenerative bone being formed instead of cavities due to the quickly degraded scaffold disappearing. These results demonstrate that the AGA scaffold has significant potential in bone regeneration applications.

Study of release kinetics and degradation thermodynamics of ferric citrate liposomes

Ferric citrate liposome (FAC-Lip) with good sustained-released property was prepared by the rotary-evaporated film-ultrasonic method, and characterized by TEM, DLS, zeta potential and encapsulation efficiency (EE%). The effects of membrane material ratios (mPC: mchol = 8:1, 10:1 and 12:1) and drug lipid ratios (mFAC: mPC = 1:4, 1:6.5 and 1:8) on the release of FAC-Lip were examined. The in vitro release kinetic models and mechanisms of FAC-Lip in artificial gastric juice (SGF) and artificial intestinal juice (SIF) compared with free-FAC were determined. The thermal degradation in PBS was also determined. The results showed that FAC-Lip with membrane material ratio (10:1) and drug lipid ratio (1:6.5) had the optimal sustained-released property, unilamellar vesicles with uniform size (178 ± 2.12 nm), negative charge (−56 ± 3.51 mV) and high encapsulation efficiency (72.77 ± 0.42%). The in vitro release kinetic models of FAC-Lip were two-phase kinetics model and the release mechanisms were non-Fick diffusion both in SGF and SIF. The thermal degradation of FAC-Lip was an endothermic and spontaneous reaction. The results may be helpful in optimizing drug-liposome design, application in food and medicine industries, and furthermore, predicting and guiding medication in vivo.

Icariin-loaded porous scaffolds for bone regeneration through the regulation of the coupling process of osteogenesis and osteoclastic activity.

ObjectiveIcariin (IC) promotes osteogenic differentiation, and it may be a potential small molecule drug for local application in bone regeneration. Icariin-loaded hydroxyapatite/alginate (IC/HAA) porous composite scaffolds were designed in this study for the potential application of the sustainable release of icariin and subsequent bone regeneration.MethodsAn icariin-loaded hydroxyapatite/alginate porous composite scaffold was prepared and characterized by SEM and HPLC for morphology and release behavior, respectively. The mechanical properties, degradation in PBS and cytotoxicity on BMSCs were also evaluated by MTT assay, compression strength and calculation of weight remaining ratio, respectively. Rabbit BMSCs were cocultured with IC/HAA scaffolds, and ALP activity and Alizarin Red staining were performed to evaluate osteogenic differentiation induction. The mRNA and protein expression level of an osteogenic gene was detected by RT-PCR and Western blotting, respectively. In vivo animal models of critical bone defects in the radius of rabbit were used. Four and 12 weeks after the implantation of IC/HAA scaffolds in the bone defect, radiographic images of the radius were obtained and scored by using the Lane and Sandhu X-ray scoring system. Tissue samples were also evaluated using H&E and Masson staining, and an osteogenic gene and Wnt signaling pathway genes were detected.ResultsA hydroxyapatite/alginate (HAA) porous composite scaffold-loaded icariin was fabricated using a freeze-drying method. Our data indicated that the icariin was loaded in alginate scaffold without compromising the macro/microstructure or mechanical properties of the scaffold. Notably, the IC/HAA promoted the proliferation of rBMSCs without exerting cytotoxicity on rBMSCs. In vivo, rabbit radius bone defect experiments demonstrated that the IC/HAA scaffold exhibited better capacity for bone regeneration than HAA, and IC/HAA upregulated the relative expression levels of an osteogenic gene and the Wnt signaling pathway genes. Most notably, the IC/HAA scaffold also inhibited osteoclast activity in vivo.ConclusionOur data suggests a promising application for the use of HAA scaffolds to load icariin and promote bone regeneration in situ through mediation of the coupling processes of osteogenesis induction and osteoclast activity inhibition.

Synergistic effects of carbohydrate polymers on the performance of hybrid injectable bone pastes

During the past few years, invasive surgery operations using injectable systems, have been applied for the treatment of osteoporosis bone defects. In this research, different injectable pastes made from natural polymer such as gelatin (Ge), carboxymethyl cellulose (CMC), alginate (Alg) and inorganic materials containing hydroxyapatite (HA) and biphasic calcium phosphate (BCP) were studied. BCP was fabricated via solid state reaction. Evaluation of BCP crystalline structure confirmed the presence of tricalcium phosphate (TCP) and HA phases. The morphology of calcium phosphate powders and the paste showed fine particles and homogeneous distribution, respectively. Consistency, injectability, washout and the rheology behavior of pastes were evaluated too. According to the results, the pastes consisted of considerable values of calcium phosphate content (about 65%) and injectability of 84% and 91% with acceptable degradation in PBS, were found for Gel/0.4% CMC and Gel/1.2% Alg pastes, respectively. It could be concluded that the addition of carbohydrate polymers (CMC and Alg) to the formulation of samples could be an effective way to adjust the final performance of the hybrid injectable bone pastes.

Synthesis of amphiphilic block copolymer of PLGA-b-(PEI-co-PEG) and characterization of the self-assembled cationic micelles

To synthesize a biodegradable and minimally cytotoxic amphiphilic block copolymer of PLGA-b-(PEI-co- PEG) and study its micellization behavior. PLGA was synthesized by ring-opening polymerization. The cross-linked copolymer of PEI-co-PEG was synthesized from the low-molecular-weight polyethyleneimine (PEI, 1800 D) and hydrophilic poly(ethylene glycol) (PEG, 2000 D). PLGA-b-(PEI-co-PEG) was synthesized by dehydration condensation reaction of PLGA and water soluble PEI-co-PEG. The biodegradability of PEI-co-PEG was evaluated according to the molecular weight change after incubation at 37 ℃ for different time. The cytotoxicity of PLGA- b-(PEI-co-PEG) and PEI-co-PEG in MCF-7 cells was determined by MTT assay. The cationic PLGA-b-(PEI-co-PEG) micelles were prepared by standard dialysis method. The particle size and Zeta potential of the micelles were measured by a Malvern laser particle size analyzer. Micelle/insulin complexes were prepared by simple mixing method and their morphology were characterized by transmission electron microscopy (TEM). The fluorescence quenching method was used to determine the stability of the micelle/insulin complexes at different salt concentrations. Amphiphilic block copolymer of PLGA-b-(PEI-co-PEG) was successfully synthesized. The half-life of PEI-co-PEG degradation in PBS at 37 ℃ was about 48 h. The 50% cell inhibiting concentration (IC50) of PLGA-b-(PEIco- PEG) and PEI-co-PEG in MCF-7 cells were 1375.7 μg/mL and 425.1 μg/mL, respectively. The micelles of PLGA-b-(PEI-co- PEG) (particle size: 99.5±2.61 nm, Zeta potential: 52.9±2.38 mV) were complexed with insulin via electrostatic interaction and formed nanoscale micelle/insulin complexes. The dissociation rate of micelle/insulin complexes in 150 mmol/L NaCl solution was 27.6%. The synthesized PEI-co-PEG shows good degradability in vitro. The cytotoxicity of PLGA-b-(PEI-co- PEG) is significantly lower than PEI-co-PEG, and PLGA-b-(PEI-co-PEG) micelle/insulin complexes have good salt- resistant stability in physiological condition.

In vitro evaluation of electrospun PLGA/PLLA/PDLLA blend fibers loaded with naringin for guided bone regeneration.

The present study was to evaluate fiber mesh loaded with naringin via electrospinning to guide bone regeneration in vitro. The naringin-loaded fiber mesh was prepared via elctrospinning of PLGA, PLLA, PDLLA blending solution with naringin. SEM showed that naringin decreased the fiber's diameter according to the concentration of naringin. After 20 days' degradation in PBS, the drug-loaded fiber meshes still kept their stability with about 10% decrease in tensile strength. In vitro release experiments showed a sustained and steady naringin releasing profile with little initial burst releasing. Compared to the mats without naringin, the fiber mats loaded with naringin showed the most pronounced enhancement of cell growth when MC3T3-E1 cells were cultured on the fiber mats. The blend fiber loaded with naringin has optimized physical properties and sustained release profile in vitro. The study presents a promising fibrous mesh material for guided bone regeneration therapy.

An Injectable Oxidized Carboxymethyl Cellulose/Polyacryloyl Hydrazide Hydrogel via Schiff Base Reaction

A series of injectable hydrogels was prepared by cross-linking oxidized carboxymethyl cellulose (oxi-CMC) with polyacryloyl hydrazide (PAH) via a Schiff base reaction under physiological conditions. The hydrogels exhibited superior performance such as appropriate rheology properties, high swelling ratio, and low degradation rate. In phosphate buffer solution (PBS, pH 7.4) at 37°C, the swelling ratio of the hydrogels ranged from 19 to 28 after 7 h, the degradation percentage of the oxi-CMC6/PAH3 hydrogel was ~47 % after 20 days. Using bovine serum albumin (BSA) as a model protein drug, the results of in vitro drug release studies demonstrated that the sustained release of BSA could be cooperatively controlled through drug diffusion and hydrogel degradation in PBS (pH 7.4) at 37°C, and the cumulative release percentage of BSA from a drug-loaded oxi-CMC6/PAH3 hydrogel was ~88 % after 8 days. The results signified that oxi-CMC6/PAH3 hydrogel could be potentially applied in the fields of drug delivery vehicles, tissue engineering, and cell encapsulation materials.

Sol-gel derived terbium-containing mesoporous bioactive glasses nanospheres: In vitro hydroxyapatite formation and drug delivery

Terbium (Tb) doped mesoporous bioactive glasses (Tb/MBG) nanospheres were successfully synthesized by a facile sol-gel method using cetyl trimethyl ammonium bromide (CTAB) as the template. Results indicated that Tb/MBG had spherical morphology (100–200nm), higher specific surface area (250–350m2/g) and narrow mesopore size distribution (2–3nm). In order to investigate the effects of Tb on the in vitro bioactivity, prepared Tb/MBG nanospheres were soaking in simulated body fluid (SBF) for 3 days, and results indicated incorporation Tb ions in the MBG nanospheres could improve the hydroxyapatite formation ability. In addition, Tb/MBG nanospheres showed controlled release property of anti-cancer drugs (DOX) and distinct degradation in PBS with different pH values. Their release mechanism can be explained by Fickian diffusion according the Higuchi model, and the delivery of DOX from Tb/MBG nanospheres can be dominated by changing the doping concentration of Tb and the values of pH. In addition, the cytotoxicity of Tb/MBG nanospheres was assessed using a cell counting kit-8 (CCK-8), and results showed that the synthesized Tb/MBG nanospheres at low concentration had no significant cytotoxicity in MC3T3 cells. These all note that this material is a promising candidate for the therapy of bone tissue regeneration.

Polyurethanes from modified castor oil and chitosan

Polyurethanes (PUs) from castor oil (CO), modified CO (MCO) by transesterification reaction, isophorone diisocyanate (IPDI) in an NCO/OH ratio equal to 1, and chitosan (CS) were synthesized to assess their potential as biomaterials. PUs were characterized by Fourier transform infrared spectroscopy, hydroxyl value (ASTM D1957), thermogravimetric analysis, Shore A hardness (ASTM D2240), and scanning electronic microscopy (SEM). Also, contact angle, water retention and in vitro degradation in PBS, and cell viability on fibroblast were performed. The hydroxyl value confirms CO modification, and IR analysis confirms urethane bond formation. The thermal assay does not show new degradation stages and polyol with a high functionality had better hardness performance due to the increase in cross-linking. The micrograph shows micro-phase separation of both polymers. The contact angle shows the hydrophobic surface with an angle over 65°, and the CS and polyol type do not affect swelling and in vitro degradation due to phase separation between both polymers. The cell viability was over 70% in all cases, and solid polymers and degradation products involve non-cytotoxic effects on the samples. The results suggest a potential for these formulations in the biomedical field.