Propolis-Based Nanofiber Patches to Repair Corneal Microbial Keratitis.

In this research, polyvinyl-alcohol (PVA)/gelatin (GEL)/propolis (Ps) biocompatible nanofiber patches were fabricated via electrospinning technique. The controlled release of Propolis, surface wettability behaviors, antimicrobial activities against the S. aureus and P. aeruginosa, and biocompatibility properties with the mesenchymal stem cells (MSCs) were investigated in detail. By adding 0.5, 1, and 3 wt.% GEL into the 13 wt.% PVA, the morphological and mechanical results suggested that 13 wt.% PVA/0.5 wt.% GEL patch can be an ideal matrix for 3 and 5 wt.% propolis addition. Morphological results revealed that the diameters of the electrospun nanofiber patches were increased with GEL (from 290 nm to 400 nm) and Ps addition and crosslinking process cause the formation of thicker nanofibers. The tensile strength and elongation at break enhancement were also determined for 13 wt.% PVA/0.5 wt.% GEL/3 wt.% Ps patch. Propolis was released quickly in the first hour and arrived at a plateau. Cell culture and contact angle results confirmed that the 3 wt.% addition of propolis reinforced mesenchymal stem cell proliferation and wettability properties of the patches. The antimicrobial activity demonstrated that propolis loaded patches had antibacterial activity against the S. aureus, but for P. aeruginosa, more studies should be performed.

3D Propolis-Sodium Alginate Scaffolds: Influence on Structural Parameters, Release Mechanisms, Cell Cytotoxicity and Antibacterial Activity.

In this study, the main aim was to fabricate propolis (Ps)-containing wound dressing patches using 3D printing technology. Different combinations and structures of propolis (Ps)-incorporated sodium alginate (SA) scaffolds were developed. The morphological studies showed that the porosity of developed scaffolds was optimized when 20% (v/v) of Ps was added to the solution. The pore sizes decreased by increasing Ps concentration up to a certain level due to its adhesive properties. The mechanical, swelling-degradation (weight loss) behaviors, and Ps release kinetics were highlighted for the scaffold stability. An antimicrobial assay was employed to test and screen antimicrobial behavior of Ps against Escherichia coli and Staphylococcus aureus strains. The results show that the Ps-added scaffolds have an excellent antibacterial activity because of Ps compounds. An in vitro cytotoxicity test was also applied on the scaffold by using the extract method on the human dermal fibroblasts (HFFF2) cell line. The 3D-printed SA-Ps scaffolds are very useful structures for wound dressing applications.

A new strategy for the treatment of middle ear infection using ciprofloxacin/amoxicillin-loaded ethyl cellulose/polyhydroxybutyrate nanofibers.

A middle ear infection occurs due to the presence of several microorganisms behind the eardrum (tympanic membrane) and is very challenging to treat due to its unique location and requires a well-designed treatment. If not treated properly, the infection can result in severe symptoms and unavoidable side effects. In this study, excellent biocompatible ethyl cellulose (EC) and biodegradable polyhydroxybutyrate (PHB) biopolymer were used to fabricate drug-loaded nanofiber scaffolds using an electrospinning technique to overcome antibiotic overdose and insufficient efficacy of drug release during treatment. PHB polymer was produced from Halomonas sp., and the purity of PHB was found to around be 90 %. Additionally, ciprofloxacin (CIP) and amoxicillin (AMX) are highly preferable since both drugs are highly effective against gram-negative and gram-positive bacteria to treat several infections. Obtained smooth nanofibers were between 116.24 and 171.82 nm in diameter and the addition of PHB polymer and antibiotics improved the morphology of the nanofiber scaffolds. Thermal properties of the nanofiber scaffolds were tested and the highest Tg temperature resulted at 229 °C. The mechanical properties of the scaffolds were tested, and the highest tensile strength resulted in 4.65 ± 6.33 MPa. Also, drug-loaded scaffolds were treated against the most common microorganisms that cause the infection, such as S.aureus, E.coli, and P.aeruginosa, and resulted in inhibition zones between 10 and 21 mm. MTT assay was performed by culturing human adipose-derived mesenchymal stem cells (hAD MSCs) on the scaffolds. The morphology of the hAD MSCs' attachment was tested with SEM analysis and hAD MSCs were able to attach, spread, and live on each scaffold even on the day of 7. The cumulative drug release kinetics of CIP and AMX from drug-loaded scaffolds were analysed in phosphate-buffered saline (pH: 7.4) within different time intervals of up to 14 days using a UV spectrophotometer. Furthermore, the drug release showed that the First-Order and Korsmeyer-Peppas models were the most suitable kinetic models. Animal testing was performed on SD rats, matrix and collagen deposition occurred on days 5 and 10, which were observed using Hematoxylin-eosin and Masson's trichrome staining. At the highest drug concentration, a better repair effect was observed. Results were promising and showed potential for novel treatment.

Advanced Applications of Silk-Based Hydrogels for Tissue Engineering: A Short Review.

Silk has been consistently popular throughout human history due to its enigmatic properties. Today, it continues to be widely utilized as a polymer, having first been introduced to the textile industry. Furthermore, the health sector has also integrated silk. The Bombyx mori silk fibroin (SF) holds the record for being the most sustainable, functional, biocompatible, and easily produced type among all available SF sources. SF is a biopolymer approved by the FDA due to its high biocompatibility. It is versatile and can be used in various fields, as it is non-toxic and has no allergenic effects. Additionally, it enhances cell adhesion, adaptation, and proliferation. The use of SF has increased due to the rapid advancement in tissue engineering. This review comprises an introduction to SF and an assessment of the relevant literature using various methods and techniques to enhance the tissue engineering of SF-based hydrogels. Consequently, the function of SF in skin tissue engineering, wound repair, bone tissue engineering, cartilage tissue engineering, and drug delivery systems is therefore analysed. The potential future applications of this functional biopolymer for biomedical engineering are also explored.

Biocompatible polyvinyl alcohol nanofibers loaded with amoxicillin and salicylic acid to prevent wound infections.

Diabetic wounds are one of the most challenging clinical conditions in diabetes, necessitating the development of new treatments to foster healing and prevent microbial contamination. In this study, polyvinyl alcohol was used as a matrix polymer, and amoxicillin (AMX) and salicylic acid (SA) were selected as bioactive compounds with antimicrobial (with AMX) and anti-inflammatory action (with SA) to obtain innovative drug-loaded electrospun nanofiber patches for the management of diabetic wounds. Scanning electron microscope images revealed the uniform and beadless structure of the nanofiber patches. Mechanical tests indicated that AMX minimally increased the tensile strength, while SA significantly reduced it. The patches demonstrated effective antibacterial activity against both gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) strains. The potential of these patches in the development of novel wound dressings is highlighted by the excellent biocompatibility with fibroblast cells maintained for up to 7 d.

A Novel Approach for the Fabrication of 3D-Printed Dental Membrane Scaffolds including Antimicrobial Pomegranate Extract.

In this study, a dental membrane scaffold was fabricated using a 3D printing technique, and the antimicrobial effect of pomegranate seed and peel extract were investigated. For the production of the dental membrane scaffold, a combination of polyvinyl alcohol, starch, and pomegranate seed and peel extracts was used. The aim of the scaffold was to cover the damaged area and aid in the healing process. This can be achieved due to the high antimicrobial and antioxidant content of pomegranate seed and peel extracts (PPE: PSE). Moreover, the addition of starch and PPE: PSE improved the biocompatibility of the scaffold, and their biocompatibility was tested using human gingival fibroblast (HGF) cells. The addition of PPE: PSE into the scaffolds resulted in a significant antimicrobial effect on S. aureus and E. faecalis bacteria. Moreover, different concentrations of starch (1%, 2%, 3% w/v) and pomegranate peel and seed extract (3%, 5%, 7%, 9%, and 11% PE v/v) were analyzed to obtain the ideal dental membrane structure. The optimum starch concentration was chosen as 2% w/v due to it giving the scaffold the highest mechanical tensile strength (23.8607 ± 4.0796 MPa). The pore sizes of each scaffold were studied by SEM analysis, and pore sizes were arranged between 155.86 and 280.96 µm without any plugging problems. Pomegranate seed and peel extracts were obtained by applying the standard extraction method. High-performance liquid chromatography was performed using the diode-array detection (HPLC-DAD) technique to analyze the phenolic content of the pomegranate seed and peel extracts. Two phenolic components of the pomegranate seed and peel extracts were investigated in the following amounts: fumaric acid (17.56 µg analyte/mg extract) and quinic acid (18.79 µg analyte/mg extract) in pomegranate seed extract and fumaric acid (26.95 µg analyte/mg extract) and quinic acid (33.79 µg analyte/mg extract) in pomegranate peel extract.

Fabrication of ethosuximide loaded alginate/polyethylene oxide scaffolds for epilepsy research using 3D-printing method.

Epilepsy is a medical condition that causes seizures and impairs the mental and physical activities of patients. Unfortunately, over one-third of patients do not receive adequate relief from oral Antiepileptic Drugs (AEDs) and continue to experience seizures. In addition to that, long term usage of Antiepileptic Drugs can cause a range of side effects. To overcome this problem, the precision of 3D printing technology is combined with the controlled release capabilities of biodegradable polymers, allowing for tailored and localized AED delivery to specific seizure sites. As a result of this novel technique, therapeutic outcomes can be enhanced, side effects of AEDs are minimized, and patient-specific dosage forms can be created. This study focused on the use of ethosuximide, an antiepileptic drug, at different concentrations (10, 13, and 15 mg) loaded into 3D-printed sodium alginate and polyethylene oxide scaffolds. The scaffolds contained varying concentrations (0.25%, 0.50%, and 0.75% w/v) and had varying pores created by 3D patterning sizes from 159.86 ± 19.9 µm to 240.29 ± 10.7 µm to optimize the releasing system for an intracranial administration. The addition of PEO changed the Tg and Tm temperatures from 65°C to 69°C and from 262°C to 267°C, respectively. Cytotoxicity assays using the human neuroblastoma cell line (SH-SY5Y) showed that cell metabolic activity reached 130% after 168 h, allowing the cells to develop into mature neural cells. In vitro testing demonstrated sustained ethosuximide release lasting 2 hours despite crosslinking with 3% CaCl2. The workpaves the way for the use of ethosuximide -loaded scaffolds for treating epilepsy.

Electrically Triggered Quercetin Release from Polycaprolactone/Bismuth Ferrite Microfibrous Scaffold for Skeletal Muscle Tissue.

Skeletal muscle tissue engineering presents a promising avenue to address the limitations pertaining to the regenerative potential of stem cells in case of injury or damage. The objective of this research was to evaluate the effects of utilizing novel microfibrous scaffolds, containing the compound quercetin (Q), on skeletal muscle regeneration. Morphological test results showed us that the combination of bismuth ferrite (BFO), polycaprolactone (PCL), and Q were bonded and well-ordered with each other, and a uniform microfibrous structure was obtained. Antimicrobial susceptibility testing of PCL/BFO/Q was conducted, and microbial reduction was found to be over 90% in the highest concentration of Q-loaded microfibrous scaffolds with the most inhibitory effect on S. aureus strains. Further, biocompatibility was investigated by performing MTT testing, fluorescence testing, and SEM imaging on mesenchymal stem cells (MSCs) to determine whether they could act as suitable microfibrous scaffolds for skeletal muscle tissue engineering. Incremental changes in the concentration of Q led to increased strength and strain, allowing muscles to withstand stretching during the healing process. In addition, electrically conductive microfibrous scaffolds enhanced the drug release capability by revealing that Q can be released significantly more quickly by applying the appropriate electric field, compared with conventional drug-release techniques. These findings suggest a possible use for PCL/BFO/Q microfibrous scaffolds in skeletal muscle regeneration by demonstrating that the combined action of both guidance biomaterials was more successful than Q itself acting alone.

Development of gallic acid-loaded ethylcellulose fibers as a potential wound dressing material.

In this study, novel fibers were designed based on ethylcellulose (EC), loaded with different concentrations of gallic acid (GA) using the electrospinning technique, in order to investigate the potential of these materials as wound dressings. The chemical structure and morphology, along with the antimicrobial and biocompatibility tests of the EC_GA fibers were investigated. To observe the chemical interactions between the components, fourier transform infrared spectroscopy (FTIR) was used. The morphological analyzes were performed using scanning electron microscope (SEM). The uniaxial tensile test machine was used to obtain mechanical performance of the fibers. MTT assay was applied to get the biocompatibility properties of the fibers and antimicrobial test was applied to obtain the antimicrobial activity of the fibers. Based on the obtained results, the highest viability value of 67.4 % was obtained for 10%EC_100GA on the third day of incubation, demonstrating that with the addition of a higher concentration of GA, the cell viability increases. The antimicrobial tests, evaluated against Staphylococcus (S.) aureus, Escherichia (E.) coli, Pseudomonas (Ps.) aeruginosa and Candida (C.) albicans, showed a >90 % microbial reduction capacity correlated with a logarithmic reduction ranging from 0.63 to 1, for 10%EC_100 GA. In vitro release tests of GA from the fibers showed that GA was totally released from 10%EC_100 GA fibers after 2880 min, demonstrating a controlled release profile. These findings demonstrated that EC_GA fibers may be suitable for application in biomedical fields such as wound dressing materials. However, further studies should be performed to increase the biocompatibility properties of the fibers.

Fucoidan-loaded electrospun Polyvinyl-alcohol/Chitosan nanofibers with enhanced antibacterial activity for skin tissue engineering.

The polymeric nanofiber may interact and control certain regeneration processes at the molecular level to repair damaged tissues. This research focuses on the development of characterization and antibacterial capabilities of polyvinyl alcohol (PVA)/chitosan (CS) nanofibres containing fucoidan (FUC) for tissue engineering as a skin tissue substitute. A control group consisting of 13% PVA/(0.1)% CS nanofiber was prepared. To confer antibacterial properties to the nanofiber, 10, 20, and 30 mg of FUC were incorporated into this control group. The scanning electron microscope (SEM) proved the homogeneous and beadless structures of the nanofibers. The antibacterial activity of the 13% PVA/(0.1)% CS/(10, 20, 30) FUC was tested against the S.aureus and E.coli and the results showed that with FUC addition, the antibacterial activities of the nanofibers increased. The biocompatibility test was performed with a fibroblast cell line for 1, 3, and 7 days of incubation and the results demonstrated that FUC addition enhanced the bioactivity of the 13% PVA/(0.1)% CS nanofibers. In addition, the biocompatibility results showed that 13% PVA/(0.1)% CS/10 FUC had the highest viability value for all incubation periods compared to the others. In addition, the tensile test results showed that; the maximum tensile strength value was observed for 13% PVA/(0.1)% CS/10 FUC nanofibers.

Evaluation of Diced Cartilage Grafts Shaped with Three-Dimensionally-Printed Bioresorbable Polycaprolactone Molds.

BACKGROUND: The main problem with the use of diced cartilage grafts is related to the difficulties encountered in shaping the graft and unpredictible graft resorption. The aim of this study was to evaluate the permanence and viability of diced cartilage grafts shaped with the help of biodegradable, three-dimensionally-printed polycaprolactone molds. METHODS: Three groups were studied in each of the eight rabbits: block cartilage (group 1), diced cartilage (group 2), and diced cartilage shaped with polycaprolactone molds (group 3). A total of 24 cartilage grafts were obtained at the end of the 12-week follow-up period, and 10 different histopathologic parameters were analyzed in each cartilage graft. RESULTS: Diced cartilages shaped with a three-dimensionally-printed polycaprolactone mold showed increased regeneration potential of chondrocytes, vascularization, and collagen production. Use of polycaprolactone molds did not cause any additional risk of inflammation, fibrosis, or metaplastic bone formation. CONCLUSIONS: In this study, it has been shown that three-dimensionally-printed polycaprolactone molds can be used safely in shaping diced cartilage grafts. In light of this study, it will be possible to produce hybrid grafts that can be used safely in many operations such as nasal reconstruction, rhinoplasty, auricle reconstruction, and repair of orbital floor fractures with the help of molds produced in more complex ways. CLINICAL RELEVANCE STATEMENT: Three-dimensionally-printed polycaprolactone molds can be used to shape diced cartilages in the areas of both aesthetic and reconstructive surgery.

3D-Printed PCL Scaffolds Combined with Juglone for Skin Tissue Engineering.

Skin diseases are commonly treated with antihistamines, antibiotics, laser therapy, topical medications, local vitamins, or steroids. Since conventional treatments for wound healing (skin allografts, amnion, xenografts, etc.) have disadvantages such as antigenicity of the donor tissue, risk of infection, or lack of basement membrane, skin tissue engineering has become a popular new approach. The current study presents the design and fabrication of a new wound-dressing material by the addition of Juglone (5-hydroxy-1,4-naphthoquinone) to a 25% Polycaprolactone (PCL) scaffold. Juglone (J) is a significant allelochemical found in walnut trees and, in this study is used as a bioactive material. The effects of different amounts of J (1.25, 2.5, 5, 7.5, and 10 mg) on the biocompatibility, mechanical, chemical, thermal, morphological, and antimicrobial properties of the 3D-printed 25% PCL scaffolds were investigated. The addition of J increased the pore diameter of the 25% PCL scaffold. The maximum pore size (290.72 ± 14 µm) was observed for the highest amount of J (10 mg). The biocompatibility tests on the scaffolds demonstrated biocompatible behavior from the first day of incubation, the 25% PCL/7.5 J scaffold having the highest viability value (118%) among all of the J-loaded scaffolds. Drug release of J into phosphate buffered saline (PBS) at pH 7.4 showed that J was completely released from all 25% PCL/J scaffolds within 7 days of incubation.

Fabrication of Electrospun Juglans regia (Juglone) Loaded Poly(lactic acid) Scaffolds as a Potential Wound Dressing Material.

Juglone (5-hydroxy-1,4-naphthoquinone) (J) is a naphthoquinone structured allelochemical that is mostly found in the roots, leaves, nut-hulls, bark, and wood of walnut (Juglans regia). In this study, the biocompatibility, mechanical, thermal, chemical, morphological, and antimicrobial properties of the poly(lactic acid) (PLA) (w/v)/J (10, 20, 30 mg) electrospun scaffolds were investigated. Based on the results of the study, it was shown that juglone addition increased the antimicrobial properties of the scaffolds against the Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), compared to the neat PLA film after 24 h of contact time. According to the tensile test results, the addition of J made the scaffolds more flexible but decreased the mechanical strength. The cytotoxicity properties of the J-added scaffolds demonstrated a toxic behavior on the first day of incubation. However, with an increase in the J ratio, the fibroblast cell metabolic activity increased for all incubation periods.

Investigation of 3D-Printed Polycaprolactone-/Polyvinylpyrrolidone-Based Constructs.

The aim of this study is to evaluate the mechanical and biological performance of cartilage-like constructs produced by 3D printing. During the investigation, poly(ε-caprolactone) (PCL) and polyvinylpyrrolidone (PVP) were used as a matrix polymer and low-molecular-weight chitosan (CS), hyaluronic acid (HA), and alginic acid sodium salt (SA) were integrated separately with the polymer matrix to fabricate the constructs. Thermal, mechanical, morphology, and chemical properties and swelling, degradation, and biocompatibility behaviors were evaluated in detail. With the addition of 3 fillers, the melting temperature of the matrix increased with the addition of fillers, and PCL/3wt.%PVP/1wt.%HA had the highest melting temperature value. Mechanical characterization results demonstrated that the printed PCL/3wt.%PVP/1wt.%CS displayed the highest compressive strength of around 9.51 MPa. The compressive strength difference between the PCL/3wt.%PVP and PCL/3wt.%PVP/1wt.%CS was 5.38 MPa. Biocompatibility properties of the constructs were tested by mitochondrial dehydrogenase activity, and in vitro studies showed that the PCL/3wt.%PVP/1wt.%HA composite construct had more cell viability than the other constructs by making use of the mesenchymal stem cell line.

Chitosan/Gold Hybrid Nanoparticles Enriched Electrospun PVA Nanofibrous Mats for the Topical Delivery of Punica granatum L. Extract: Synthesis, Characterization, Biocompatibility and Antibacterial Properties.

PURPOSE: Intending to obtain Punica granatum L. extract (PE)-loaded drug delivery system of better impact and biomedical applicability, the current study reports the use of crosslinked PVA nanofibers (NFs) as platforms incorporating different amounts of biosynthesized PE-CS-gold nanoparticles (PE-CS-Au NPs). METHODS: PE-conjugated CS-Au nanoparticles (PE-CS-Au NPs) were synthesized via green chemistry approach. The formation of PE-CS-Au NPs was confirmed by UV spectroscopy, DLS, SEM and STEM. PE-CS-Au NPs were then dispersed into polyvinyl alcohol (PVA) solution at different ratios, where the optimized ratios were selected for electrospinning and further studies. Crosslinking of PE-CS-Au NPs loaded PVA nanofibers (NFs) was performed via glutaraldehyde vapor. The morphology, chemical compositions, thermal stability and mechanical properties of PE-CS-Au NPs loaded NFs were evaluated by SEM, FTIR and DSC. Swelling capacity, biodegradability, PE release profiles, release kinetics, antibacterial and cell biocompatibility were also demonstrated. RESULTS: By incorporating PE-CS-Au NPs at 0.6% and 0.9%, the diameters of the nanofibers decreased from 295.7±83.1 nm in neat PVA to 165.6±43.4 and 147.8±42.7 nm, respectively. It is worth noting that crosslinking and incorporation of PE-CS-Au NPs improved thermal stability and mechanical properties of the obtained NFs. The release of PE from NFs was controlled by a Fickian diffusion mechanism (n value ˂0.5), whereas Higuchi was the mathematical model which could describe this release. The antibacterial activity was found to be directly proportional to the amount of the incorporated PE-CS-Au NPs. The human fibroblasts (HFF-1) showed the highest viability (123%) by seeding over the PVA NFs mats containing 0.9% PE-CS-Au NPs. CONCLUSION: The obtained results suggest that the electrospun PVA NFs composites containing 0.9% PE-CS-Au NPs can be used as antibacterial agents against antibiotic-resistant bacteria, and as suitable scaffolds for cell adhesion, growth and proliferation of fibroblast populations.

Development and In Vitro Evaluation of Biocompatible PLA-Based Trilayer Nanofibrous Membranes for the Delivery of Nanoceria: A Novel Approach for Diabetic Wound Healing.

The attempts to explore and optimize the efficiency of diabetic wound healing's promotors are still in progress. Incorporation of cerium oxide nanoparticles (nCeO2) in appropriate nanofibers (NFs) can prolong and maximize their promoting effect for the healing of diabetic wounds, through their sustained releases, as well as the nanofibers role in mimicking of the extra cellular matrix (ECM). The as-prepared nCeO2 were analyzed by using UV-Vis spectroscopy, XRD, SEM-EDX, TEM and FTIR, where TEM and SEM images of both aqueous suspension and powder showed spherical/ovoid-shaped particles. Biodegradable trilayer NFs with cytobiocompatibility were developed to sandwich nCeO2 in PVA NFs as a middle layer where PLA NFs were electrospun as outer bilayer. The nCeO2-loaded trilayer NFs were characterized by SEM, XRD, FTIR and DSC. A two-stage release behavior was observed when the nanoceria was released from the trilayer-based nanofibers; an initial burst release took place, and then it was followed by a sustained release pattern. The mouse embryo fibroblasts, i.e., 3T3 cells, were seeded over the nCeO2-loaded NFs mats to investigate their cyto-biocompatibility. The presence and sustained release of nCeO2 efficiently enhance the adhesion, growth and proliferation of the fibroblasts' populations. Moreover, the incorporation of nCeO2 with a higher amount into the designed trilayer NFs demonstrated a significant improvement in morphological, mechanical, thermal and cyto-biocompatibility properties than lower doses. Overall, the obtained results suggest that designated trilayer nanofibrous membranes would offer a specific approach for the treatment of diabetic wounds through an effective controlled release of nCeO2.

Fabrication of tissue-engineered tympanic membrane patches using 3D-Printing technology.

In recent years, scaffolds produced in 3D printing technology have become more widespread tool due to providing more advantages than traditional methods in tissue engineering applications. In this research, it was aimed to produce patches for the treatment of tympanic membrane perforations which caused significant hearing loss by using 3D printing method. Polylactic acid(PLA) scaffolds with Chitosan(CS) and Sodium Alginate(SA) added in various ratios were prepared for artificial eardrum patches. Different amounts of chitosan and sodium alginate added to PLA increased the biocompatibility of the produced scaffolds. The created patches were designed by mimicking the thickness of the natural tympanic membrane thanks to the precision provided by the 3D printed method. The produced scaffolds were analyzed separately for chemical, morphological, mechanical and biocompatibility properties. Scanning electron microscope (SEM), Fourier-transform infrared (FT-IR) spectroscopy was performed to observe the surface morphology and chemical structure of the scaffolds. Mechanical, thermal and physical properties, swelling and degradation behaviors were examined to fully analyze whole characteristic features of the samples. Cell culture study was also performed to demonstrate the biocompatibility properties of the fabricated scaffolds with human adipose tissue-derived mesenchymal stem cells (hAD-MSCs). 15 wt % PLA was selected as the control group and among all concentrations of CS and SA, groups containing 3 wt% CS and 3 wt% SA showed significantly superior and favorable features in printing quality. The research continued with these two scaffolds (3 wt% CS, and 3 wt% SA), which showed improved print quality when added to PLA. Overall, these results show that PLA/CS and PLA/SA 3D printed artificial patches have the potential to tissue engineering solutions to repair tympanic membrane perforation for people with hearing loss.

Electrically Triggered Drug Delivery from Novel Electrospun Poly(Lactic Acid)/Graphene Oxide/Quercetin Fibrous Scaffolds for Wound Dressing Applications.

The novel controlled and localized delivery of drug molecules to target tissues using an external electric stimulus makes electro-responsive drug delivery systems both feasible and desirable, as well as entailing a reduction in the side effects. Novel micro-scaffold matrices were designed based on poly(lactic acid) (PLA) and graphene oxide (GO) via electrospinning. Quercetin (Q), a natural flavonoid, was loaded into the fiber matrices in order to investigate the potential as a model drug for wound dressing applications. The physico-chemical properties, electrical triggering capacity, antimicrobial assay and biocompatibility were also investigated. The newly fabricated PLA/GO/Q scaffolds showed uniform and smooth surface morphologies, without any beads, and with diameters ranging from 1107 nm (10%PLA/0.1GO/Q) to 1243 nm (10%PLA). The in vitro release tests of Q from the scaffolds showed that Q can be released much faster (up to 8640 times) when an appropriate electric field is applied compared to traditional drug-release approaches. For instance, 10 s of electric stimulation is enough to ensure the full delivery of the loaded Q from the 10%PLA/1%GO/Q microfiber scaffold at both 10 Hz and at 50 Hz. The antimicrobial tests showed the inhibition of bacterial film growth. Certainly, these materials could be loaded with more potent agents for anti-cancer, anti-infection, and anti-osteoporotic therapies. The L929 fibroblast cells cultured on these scaffolds were distributed homogeneously on the scaffolds, and the highest viability value of 82.3% was obtained for the 10%PLA/0.5%GO/Q microfiber scaffold. Moreover, the addition of Q in the PLA/GO matrix stimulated the production of IL-6 at 24 h, which could be linked to an acute inflammatory response in the exposed fibroblast cells, as a potential effect of wound healing. As a general conclusion, these results demonstrate the possibility of developing graphene oxide-based supports for the electrically triggered delivery of biological active agents, with the delivery rate being externally controlled in order to ensure personalized release.

3D bioprinting applications in neural tissue engineering for spinal cord injury repair.

Spinal cord injury (SCI) is a disease of the central nervous system (CNS) that has not yet been treated successfully. In the United States, almost 450,000 people suffer from SCI. Despite the development of many clinical treatments, therapeutics are still at an early stage for a successful bridging of damaged nerve spaces and complete recovery of nerve functions. Biomimetic 3D scaffolds have been an effective option in repairing the damaged nervous system. 3D scaffolds allow improved host tissue engraftment and new tissue development by supplying physical support to ease cell function. Recently, 3D bioprinting techniques that may easily regulate the dimension and shape of the 3D tissue scaffold and are capable of producing scaffolds with cells have attracted attention. Production of biologically more complex microstructures can be achieved by using 3D bioprinting technology. Particularly in vitro modeling of CNS tissues for in vivo transplantation is critical in the treatment of SCI. Considering the potential impact of 3D bioprinting technology on neural studies, this review focus on 3D bioprinting methods, bio-inks, and cells widely used in neural tissue engineering and the latest technological applications of bioprinting of nerve tissues for the repair of SCI are discussed.