Degradation Rate Of Scaffolds Research Articles

3D printing of bioglass-reinforced β-TCP porous bioceramic scaffolds

The use of bioglass (BG) has been proved to be an effective strategy for reducing the sintering temperature and improving the degradability of bioceramics. In this work, a Na2O–CaO–MgO–P2O5 bioglass with a low melting temperature and an average particle size of 1.3 μm and crystalline β-tricalcium phosphate (β-TCP) with an average particle size of 600 nm were first prepared separately. 3D printing was then used to fabricate the β-TCP/BG composite porous ceramic scaffolds. The Na2O–CaO–MgO–P2O5 bioglass-reinforced β-TCP porous ceramic scaffolds demonstrated a significant enhancement in their mechanical properties, degradability and biocompatibility compared with pure β-TCP ceramics. The results showed that the compressive strength and elastic modulus of the reinforced β-TCP ceramic scaffold were 8.34 MPa and 208.5 MPa, respectively, and the degradation rate of the β-TCP porous ceramic scaffolds increased by a factor of 2.99. In addition, the optimized scaffold distinctly promoted MC3T3-E1 osteoblast cell proliferation. Na2O–CaO–MgO–P2O5 bioglass-reinforced β-TCP porous ceramic scaffold has great potential for application in bone regeneration.

Effect of mechanical stimulation on the degradation of poly(lactic acid) scaffolds with different designed structures

Biodegradability is one of the required scaffold functions for bone tissue engineering, and it is influenced by the mechanical micro-environment after scaffold implantation into body. This paper aimed to develop a mathematical model to numerically study the mechanical impact on the degradation of poly (lactic acid) (PLA) scaffolds with different designed structures. In addition, the diffusion-governed autocatalysis on the scaffold degradation was also included, and the scaffold collapse time by an author-developed algorithm was determined. The results showed that an increase in mechanical stimulation led to an increase in the scaffold degradation rate. Moreover, different structures with a similar porosity shared a degradation tendency but had different collapse times, which was very sensitive to the diffusion coefficient of the scaffold. The present study could be helpful to understand the dynamic degradation process of PLA scaffolds, and guide the design of PLA material and scaffold structure. It may be also used as a tool for the evaluation of the in vitro and in vivo degradation performance of scaffolds.

Biocompatibility and biodegradation properties of polycaprolactone/polydioxanone composite scaffolds prepared by blend or co-electrospinning

Electrospun polymer scaffolds are regarded as an ideal tissue engineering scaffold due to similar morphological properties with the native extracellular matrix. Among these, polycaprolactone is widely used to fabricate electrospun fibrous scaffolds due to its excellent biocompatibility, good mechanical properties, and ease of manufacture. However, its low biodegradation rate has a negative influence on its application in tissue engineering scaffold. To address this issue, this study prepared hybrid scaffolds composed of polycaprolactone and polydioxanone (a fast-degrading polyether-ester) via either the blend or co-electrospinning. Subsequently, the structural characteristics, mechanical strength, in vitro/vivo degradation, cellularization, and vascularization of two kinds of hybrid scaffolds were evaluated to decide which method is more suitable for producing tissue engineering scaffolds. The incorporation of polydioxanone increased the mechanical strength of both composite scaffolds. Moreover, co-electrospun scaffolds exhibited improved hydrophilicity compared to blend scaffolds. The results of in vitro and in vivo degradation studies showed that the degradation rate of both composite scaffolds was faster than that of neat polycaprolactone scaffolds due to the incorporated polydioxanone component. Especially in co-electrospun scaffolds, the fast degradation of polydioxanone fiber gave rise to larger pore size, thus leading to faster cellularization and better vascularization compared to blend scaffolds. Therefore, co-electrospinning was demonstrated to be superior to blend electrospinning for the preparation of composite scaffolds. Co-electrospun polycaprolactone–polydioxanone scaffolds may be promising candidates for tissue engineering.

The Application of Multi-Walled Carbon Nanotubes in Bone Tissue Repair Hybrid Scaffolds and the Effect on Cell Growth In Vitro.

In this study, composite scaffolds with different multi-walled carbon nanotubes (MWCNTs) content were prepared by freeze-drying. These scaffolds were characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), porosity, hydrophilicity, mechanical strength, and degradation. The MWCNTs scaffolds were structurally sound and had porous structures that offered ample space for adherence, proliferation, and differentiation of MC3T3-E1 cells, and also supported the transport of nutrients and metabolic waste. CS/Gel/nHAp/0.3%MWCNTs scaffolds provided the best outcomes in terms of scaffold porosity, hydrophilicity, and degradation rate. However, CS/Gel/nHAp/0.6%MWCNTs scaffolds were found to support the optimal growth, homogenous distribution, and biological activity of MC3T3-E1 cells. The excellent properties of CS/Gel/nHAp/0.6%MWCNTs scaffolds for the adhesion, proliferation, and osteogenesis differentiation of MC3T3-E1 cells in vitro highlights the potential applications of this scaffold in bone tissue regeneration.

Synthesis and characterization of conductive neural tissue engineering scaffolds based on urethane-polycaprolactone

Polymeric biomaterials play a key role in enhancement of lengthy nerve regeneration and various types of scaffolds were used to pave the way for nerve regeneration. Electrospun fibrous scaffolds have special potential applicability in controlling the cell behaviors such as adhesion, growth, proliferation and function. This study attempted to design a conductive and porous fibrous scaffold containing polycaprolactone (PCL) and polyaniline (PANI) with controllable degradation rate by adding urethane groups in scaffold structures. FTIR and NMR analysis was used to characterize the chemical bonds. Morphology, porosity, conductivity and degradation rate of scaffolds were also evaluated. To assess the cell–scaffold interaction, PC-12 cell line was cultured on the scaffolds. Results showed that the degradation rate of composite samples significantly increased in 50 time period. It seems that these results suggest that the composite fibrous scaffolds having proportions of UPCL/PCL/PANI45:20:35 exhibit the most balanced properties that meet all of the required specifications for neural cells and possess a potential application in neural tissue engineering.

Characterization of the Kinetics and Mechanism of Degradation of Human Mesenchymal Stem Cell-Laden Poly(ethylene glycol) Hydrogels.

Human mesenchymal stem cells (hMSCs) are motile cells that migrate from their native niche to wounded sites where they regulate inflammation during healing. New materials are being developed as hMSC delivery platforms to enhance wound healing. To act as an effective wound healing material, the hydrogel must degrade at the same rate as tissue regeneration, while maintaining a high cell viability. This work determines the kinetics and mechanism of cell-mediated degradation in hMSC-laden poly(ethylene glycol) (PEG) hydrogels. We use a well-established hydrogel scaffold that is composed of a backbone of four-arm star PEG functionalized with norbornene that is cross-linked with a matrix metalloproteinase (MMP) degradable peptide. This peptide sequence is cleaved by cell-secreted MMPs, which allow hMSCs to actively degrade the hydrogel during motility. Three mechanisms of degradation are characterized: hydrolytic, noncellular enzymatic and cell-mediated degradation. We use bulk rheology to characterize hydrogel material properties and quantify degradation throughout the entire reaction. Hydrolysis and noncellular enzymatic degradation are first characterized in hydrogels without hMSCs, and follow first-order and Michaelis-Menten kinetics, respectively. A high cell viability is measured in hMSC-laden hydrogels, even after shearing on the rheometer. After confirming hMSC viability, bulk rheology characterizes cell-mediated degradation. When comparing cell-mediated degradation to noncellular degradation mechanisms, cell-mediated degradation is dominated by enzymatic degradation. This indicates hydrogels with hMSCs are degraded primarily due to cell-secreted MMPs and very little network structure is lost due to hydrolysis. Modeling cell-mediated degradation provides an estimate of the initial concentration of MMPs secreted by hMSCs. By changing the concentration of hMSCs, we determine the initial MMP concentration increases with increasing hMSC concentration. This work characterizes the rate and mechanism of scaffold degradation, giving new insight into the design of these materials as implantable scaffolds.

Tailoring degradation rates of silk fibroin scaffolds for tissue engineering

In tissue regenerative medicine, developing tunable degradation rate of biomaterials for predictive functional outcomes remains critical. The implanted scaffolds should degrade gradually along with the tissue regeneration, and the optimal degradation rate of scaffold depends on the tissue type to be regenerated. Herein, the tunable degradation rates of silk fibroin (SF) scaffolds were fabricated through controlling dissolution, hydrolyzing conditions, and freeze-drying. The pore size, water adsorption capacity, and mechanical properties of scaffolds were associated with their average molecular weights. Moreover, in vitro cytotoxicity tests demonstrated that rapid degradation of SF scaffolds would facilitate the Schwann cells proliferation. Furthermore, in vitro enzymatic degradation and in vivo subcutaneous implantation experiments illustrated that SF scaffolds degradation behaviors could be well regulated. Immunohistochemistry staining experiments suggested that SF scaffold-degradation products could promote the endothelial cells proliferation. These results indicate that SF tunable degradation rates are promising candidates in regenerative medicine. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 104-113, 2019.

A biodegradable hybrid inorganic nanoscaffold for advanced stem cell therapy

Stem cell transplantation, as a promising treatment for central nervous system (CNS) diseases, has been hampered by crucial issues such as a low cell survival rate, incomplete differentiation, and limited neurite outgrowth in vivo. Addressing these hurdles, scientists have designed bioscaffolds that mimic the natural tissue microenvironment to deliver physical and soluble cues. However, several significant obstacles including burst release of drugs, insufficient cellular adhesion support, and slow scaffold degradation rate remain to be overcome before the full potential of bioscaffold–based stem-cell therapies can be realized. To this end, we developed a biodegradable nanoscaffold-based method for enhanced stem cell transplantation, differentiation, and drug delivery. These findings collectively support the therapeutic potential of our biodegradable hybrid inorganic (BHI) nanoscaffolds for advanced stem cell transplantation and neural tissue engineering.

Synthesis and Properties of PGS-Li Scaffold

Lithium ion-doped polyglycerol sebacate scaffold(PGS)-Li was synthesized by adding lithium ions to polyglycerol sebacate(PGS) during its crosslinking process due to the specific effects of lithium ions on periodontal ligament cells, cementoblasts and the eminent performance of PGS. The molecular mass, composition, structure, porosity, thermal properties, and hydrophilicity of the composite were characterized by gel permeation chromatography(GPC), Fourier transform infrared spectroscopy(FTIR), inductively coupled plasma optical emission spectrometer(ICP-OES), scanning electron microscopy(SEM), X-ray photoelectron spectroscopy(XPS), thermogravimetric analyzer(TGA) and contact angle measurments, and the degradation of the material was evaluated by in vitro degradation experiments. The biological activity of PGS-Li scaffold was detected by calcein-AM staining and cytotoxicity test. The results indicate that PGS-Li scaffold has been successfully synthesized, which has similar composition and structure to PGS, but slightly larger molecular weight. In addition, the porosity and pore size of PGS-Li scaffold basically meet the requirements of engineering scaffold materials and the seaffold shows better performance in terms of hydrophilicity and thermal stability than PGS. In vitro degradation experimental results show that the degradation rate of PGS-Li scaffold is higher than that of PGS. What’s more, the results of cytotoxicity test and cell staining show that there is no significant difference in the proliferation and cell morphology of cementoblasts.

Degradation rate of DNA scaffolds and bone regeneration

Scaffolds implanted into bone defect sites must achieve optimal biodegradation rates while appropriately filling the void as new bone formation progresses. We recently developed a unique biomaterial consisting of salmon deoxyribose nucleic acid (DNA) and protamine, which can be used as an osteoconductive scaffold for tissue engineering. The aim of the present study was to elucidate how the degradation rate of the scaffold affects bone regeneration. We examined the relationships between the degradation rate of salmon DNA scaffolds and new bone formation using a rat skin flank subcutaneous model and rat calvarial defect model. The degradation rates of the scaffolds were proportional to the durations of pretreatment with ultraviolet (UV) light irradiation. The biodegradation rates of the scaffolds were also dependent on the duration of UV irradiation, as tested a subcutaneous tissue implantation. Scaffolds irradiated with UV light for 0.5 h maintained gradual biodegradation of phosphate compared with scaffolds irradiated for 0 or 3 h. In the calvarial defect model, we found that new bone formation was higher in rats treated with scaffolds irradiated with UV light for 0.5 h compared with those irradiated with UV light for 0 or 3.0 h. The present results suggest that bioengineering of scaffolds for biodegradation is important to regenerate bone. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 122-128, 2019.

Nano-biocomposite scaffolds of chitosan, carboxymethyl cellulose and silver nanoparticle modified cellulose nanowhiskers for bone tissue engineering applications

In the present work, we aimed to synthesize highly efficient nano-composite polymeric scaffolds with controllable pore size and mechanical strength. We prepared nanocomposite (CCNWs-AgNPs) of silver nanoparticles (AgNPs) decorated on carboxylated CNWs (CCNWs) which serves dual functions of providing mechanical strength and antimicrobial activity. Scaffolds containing chitosan (CS) and carboxymethyl cellulose (CMC) with varying percent of nanocomposite were fabricated using freeze drying method. XRD and FESEM analysis of nanocomposite revealed highly crystalline structure with AgNPs (5.2 nm dia) decorated on ~200 nm long CCNWs surface. FTIR analysis confirmed the interaction between CCNWs and AgNPs. Incorporation of nanocomposite during scaffolds preparation helped in achieving the desirable 80–90% porosity with pore diameter ranging between 150 and 500 μm and mechanical strength was also significantly improved matching with the mechanical strength of cancellous bone. The swelling capacity of scaffolds decreased after the incorporation of nanocomposite. In turn, scaffold degradation rate was tuned to support angiogenesis and vascularization. Scaffolds apart from exhibiting excellent antimicrobial activity, also supported MG63 cells adhesion and proliferation. Incorporation of CCNWs also resulted in improved biomineralization for bone growth. Overall, these studies confirmed excellent properties of fabricated scaffolds, making them self-sustained and potential antimicrobial scaffolds (without any loaded drug) to overcome bone related infections like osteomyelitis.

Blocking of matrix metalloproteinases-13 responsive peptide in poly(urethane urea) for potential cartilage tissue engineering applications.

The matching of scaffold degradation rate with neotissue growth is required for tissue engineering applications. Timely provision of proper spaces especially for cartilage tissue engineering plays a pivotal role in chondrocyte cluster formation. In this study, poly(urethane urea) was synthesized using conventional two-stage method by extending the isocyanate group terminated prepolymers with different amounts of GPLGLWARK peptide, which responses the degrading induced by matrix metalloproteinase 13, the main proteinase for cartilage matrix degradation. The Fourier transform infrared spectrometer with the attenuated total reflection and 1H nuclear magnetic resonance spectra revealed that the peptides were introduced to poly(urethane urea) according to the characteristic absorption bands of the peptide and the newly formed urea bonds. The ultraviolet-visible spectroscopy spectra showed that the weight percentages of the peptide in the three poly(urethane urea) were 25%, 32%, and 35%. Atomic force microscopy images revealed that phase separation occurred in all poly(urethane urea) samples and became increasingly apparent with increasing amount of peptides introduced. Mechanical tests showed that the poly(urethane urea) strength increased with increasing amount of peptides in poly(urethane urea). Poly(urethane urea) proteolysis in matrix metalloproteinase 13 solution was more rapid than hydrolysis in aqueous buffer, and proteolysis rate was dependent on the amount of peptides in poly(urethane urea). Cell proliferation on the material surface in vitro displayed nontoxicity for all synthesized poly(urethane urea). In vivo subcutaneous implantation evaluation revealed the presence of local foreign body reactions triggered by poly(urethane urea) but was not due to peptide in poly(urethane urea). Moreover, the synthesized poly(urethane urea) with significant phase separation did not degrade under the matrix metalloproteinase 13 free subcutaneous environment, but poly(urethane urea) with minimal phase separation was degraded by attacking of the enzymes adsorbed on the hydrophobic surface through non-specific adsorption.

Fabrication of 3D porous poly(lactic acid)-based composite scaffolds with tunable biodegradation for bone tissue engineering

Success of biomimetic scaffold relies on the comparability of its microarchitecture and physicochemical properties to the natural bone. However, porous scaffolds which simultaneously possessed excellent mechanical properties, favorable bioactivity and tunable biodegradation were rarely reported. Herein, to integrate the high stiffness of hydroxyapatite (HA), the formability of lignocellulose (LG), the processability of poly(lactic acid) (PLA) and the bioactivity of sol-gel derived 58S bioactive glass (BG), poly(lactic acid) (PLA)-based composite scaffolds were fabricated by a simple technique of combining the solvent casting/particulate leaching and sol-gel method. The resultant scaffolds showed well-defined interconnected porous structure with pore size of 200–400 μm and rough pore wall, which was reported to be potentially beneficial for cell adhesion and ingrowth. In addition, the mechanical properties were obviously improved by the reinforcements of LG, HA, and BG. In vitro biomineralization studies indicated the incorporation of BG significantly enhanced the bioactivity of composite scaffolds. Specially, the degradation rate of scaffolds could be easily regulated by adjusting the BG content to match the regeneration of new bone. The developed PLA-based composite scaffolds might have a great potential for bone regeneration.

Porous Poly(ε-caprolactone)-Poly(l-lactic acid) Semi-Interpenetrating Networks as Superior, Defect-Specific Scaffolds with Potential for Cranial Bone Defect Repair.

The treatment of irregular cranial bone defects is currently limited due to the graft resorption that can occur when an ill-fitting interface exists between an autograft and the surrounding tissue. A tissue engineering scaffold able to achieve defect-specific geometries could improve healing. This work reports a macroporous, shape memory polymer (SMP) scaffold composed of a semi-interpenetrating network (semi-IPN) of thermoplastic poly(l-lactic acid) (PLLA) within cross-linked poly(ε-caprolactone) diacrylate (PCL-DA) that is capable of conformal fit within a defect. The macroporous scaffolds were fabricated using a fused salt template and were also found to have superior, highly controlled properties needed for regeneration. Specifically, the scaffolds displayed interconnected pores, improved rigidity, and controlled, accelerated degradation. Although slow degradation rates of scaffolds can limit healing, the unique degradation behavior observed could prove promising. Thus, the described SMP semi-IPN scaffolds overcome two of the largest limitations in bone tissue engineering: defect "fit" and tailored degradation.

Biodegradation of PLA-Pennisetum purpureum based biocomposite scaffold

The in vitro degradation and mechanical properties of a 3D porous Pennisetum purpureum (PP)/polylactic acid (PLA) —based scaffold was investigated. In this study, composite scaffolds with PP to PLA ratio of 0%, 10%, 20%, and 30% were immersed in PBS solution at 37 °C for 40 days. Interestingly, the degradation rate was reduced for the PLA/PP20 scaffold, though insignificantly, this could be attributed to the improved mechanical properties and stronger fibre-matrix interface. The FESEM results indicated that a sound fibre-matrix interface was formed in the PLA/PP20 scaffold, which reflected the addition of P. purpureum into PLA decreasing the degradation rate compared to in pure PLA scaffolds. The results suggest that the P. purpureum/PLA scaffold degradation rate can be altered and controlled to meet the requirement imposed by a given tissue engineering application.

Silk fibroin-chondroitin sulfate scaffold with immuno-inhibition property for articular cartilage repair.

Severe cartilage defect such as osteoarthritis (OA) is difficult to self-repair because of its avascular, aneural and alymphatic nature. Current scaffolds often focus on providing sufficient mechanical support or bio-mimetic structure to promote cartilage repair. Thus, silk has been adopted and investigated broadly. However, inflammation is one of the most important factors in OA. But few scaffolds for cartilage repair reported anti-inflammation property. Meanwhile, chondroitin sulfate (CS) is a glycosaminoglycan present in the natural cartilage ECM, and has exhibited a number of useful biological properties including anti-inflammatory activity. Thus, we designed this silk-CS scaffold and proved that this scaffold exhibited good anti-inflammatory effects both in vitro and in vivo, promoted the repair of articular cartilage defect in animal model.

In vitro degradation of a 3D porous Pennisetum purpureum/PLA biocomposite scaffold

The in vitro degradation and mechanical properties of a 3D porous Pennisetum purpureum (PP)/polylactic acid (PLA)-based scaffold were investigated. In this study, composite scaffolds with PP to PLA ratios of 0%, 10%, 20%, and 30% were immersed in a PBS solution at 37°C for 40 days. Compression tests were conducted to evaluate the compressive strength and modulus of the scaffolds, according to ASTM F451-95. The compression strength of the scaffolds was found to increase from 1.94 to 9.32MPa, while the compressive modulus increased from 1.73 to 5.25MPa as the fillers’ content increased from 0wt% to 30wt%. Moreover, field emission scanning electron microscopy (FESEM) and X-ray diffraction were employed to observe and analyse the microstructure and fibre-matrix interface. Interestingly, the degradation rate was reduced for the PLA/PP20 scaffold, though insignificantly, this could be attributed to the improved mechanical properties and stronger fibre-matrix interface. Microstructure changes after degradation were observed using FESEM. The FESEM results indicated that a strong fibre-matrix interface was formed in the PLA/PP20 scaffold, which reflected the addition of P. purpureum into PLA decreasing the degradation rate compared to in pure PLA scaffolds. The results suggest that the P. purpureum/PLA scaffold degradation rate can be altered and controlled to meet requirements imposed by a given tissue engineering application.

COMPARISON ON IN VITRO DEGRADATION OF POLYCAPROLACTONE AND POLYCAPROLACTONE/GELATIN NANOFIBROUS SCAFFOLD

Tissue engineering has emerged to provide a new medical therapy in helping tissue regrowth and regeneration by employing scaffold as an artificial supporting structure for cellular growth. Many polymers have been utilized in the fabrication of these artificial scaffolds, but there is still a need to fabricate hydrophilic nanofibrous scaffold with appropriate degradation rate. In this study, polycaprolactone (PCL) and polycaprolactone/gelatin (PCL/Ge) 70:30 nanofibrous scaffolds were fabricated using electrospinning technique and compared on in vitro degradation rate to determine a more suitable scaffold for skin tissue engineering application. In vitro degradation was evaluated by morphological changes, water uptake, and chemical bonding until 12 weeks. Result shows that both PCL and PCL/Ge (70:30) nanofibrous scaffolds were degraded after 8th week. However, the degradation rate of PCL nanofibrous scaffold is slower and does not has obvious morphological changes. PCL/Ge (70:30) nanofibrous scaffold with faster degradation rate have the potential for skin tissue engineering application.

Optimized composition of nanocomposite scaffolds formed from silk fibroin and nano-TiO2 for bone tissue engineering

Natural silk fibroin (SF) polymer has biomedical and mechanical properties as a biomaterial for bone tissue engineering scaffolds. Freeze-dried porous nanocomposite scaffolds were prepared from silk fibroin and titanium dioxide (TiO2) nanoparticles as a bioactive reinforcing agent by a phase separation method. In order to fabricate SF/TiO2 scaffolds, 5, 10, 15 and 20wt% of the TiO2 were added to the SF. The phase structure, functional groups and morphology of the scaffolds were evaluated using X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy techniques, respectively. Porosity of the scaffolds was measured by Archimedes' Principle. In addition, mechanical properties of prepared scaffolds were evaluated by measuring the compressive strength and compressive modulus. The bioactivity property of these scaffolds was examined for 7, 14, 21 and 28days immersion in simulated body fluid (SBF) at 37°C and the in vitro degradation was studied by incubation in phosphate buffered saline (PBS) at 37°C and pH7.4 for up to 30days. Moreover, the scaffolds' biocompatibility was evaluated by seeding and culture of SaOS-2 osteoblast-like cells and assessment of their proliferation with MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. Results showed that the prepared scaffolds had directional porosity and the reduction of porosity in composite scaffolds with higher contents of TiO2 nanoparticles resulted to an improvement of the mechanical strength. The macroporous structures with open interconnected and directional pores were successfully obtained without applying any porogen or inorganic solvent. The bioactivity of these scaffolds was confirmed by scanning electron microscopy (SEM) showing surface crystallization of the apatite layer proportional to the duration of immersion in the SBF and the degradation rate of scaffolds were increased by increasing the TiO2 content. The osteoblast-like cells showed a high attachment and proliferation on these scaffolds and their viability was increased with increasing the SF content. Finally, an optimum composition of SF/TiO2 nanocomposite scaffolds was selected.

Functionalized Asymmetric Poly (Lactic Acid)/Gelatin Composite Membrane for Guided Periodontal Tissue Regeneration

Aim: Periodontitis is caused by chronic gingival inflammation and affects a large population in the world. Although guided tissue regeneration (GTR) therapy has been proven to be an effective treatment, the deficiency in the symmetrical design of all the GTR membrane in the market leaves large space for improvement. Therefore, we designed a novel asymmetrical bi-layer PLA/gelatin composite membrane for treating periodontitis. Methods: The PLA side was fabricated by electrospinning with metronidazole (MNA) pre-mixed with the PLA solution. The gelatin side containing bioglass (BG) 45S5 was fabricated with freeze-drying process and cross-linked with PLA membrane. The bio-compatibility of the membrane was evaluated in vitro using NIH3T3 cells. The releasing of MNA was measured by spectrophotometer. The bioactivity of the membrane was evaluated by hydroxyapatite (HA) deposit and determined by FTIR spectrometer. The ionic concentration of Ca2+ and was measured by ICPOES. The expression of the osteogenesis makers was determined by qRT-PCR. Results: The bi-layer PLA/gelatin composite membrane is biocompatible and bioactive. The releasing of MNA can rapidly reach the anti-bacterial effective concentration. Interestingly, the incorporation of MNA modulated the degradation rate of PLA scaffold to meet the requirement of tissue regeneration. Meanwhile, the embedding of the BG powder in the gelatin porous layer provided a favorable Ca2+ and ion environment for the regeneration of the alveolar bone tissue. Conclusions: Taken together, this bi-layer GTR membrane is closer to the physiological structure of the periodontal. The addition of MNA and BG makes it more powerful in treating periodontitis. Moreover, this research provides an example of biomimetic design in fabricating biomaterial for clinical applications.