Biocompatible scaffolds constructed by chondroitin sulfate microspheres conjugated 3D-printed frameworks for bone repair.

Most bone repair scaffolds are multi-connected channel structure, but the hollow structure is not conducive to the transmission of active factors, cells and so on. Here, microspheres were covalently integrated into 3D-printed frameworks to form composite scaffolds for bone repair. The frameworks composed of double bond modified gelatin (Gel-MA) and nano-hydroxyapatite (nHAP) provided strong support for related cells climbing and growth. Microspheres, which were made of Gel-MA and chondroitin sulfate A (CSA), were able to connect the frameworks like bridges, providing channels for cells migration. Additionally, CSA released from microspheres promoted the migration of osteoblasts and enhanced osteogenesis. The composite scaffolds could effectively repair mouse skull defect and improve MC3T3-E1 osteogenic differentiation. These observations confirm the bridging effect of microspheres rich in chondroitin sulfate and also determine that the composite scaffold can be as a promising candidate for enhanced bone repair.

Efficacy of a novel polyoxazoline-based hemostatic patch in liver and spleen surgery.

BACKGROUND: A new hemostatic sealant based on a N-hydroxy-succinimide polyoxazoline (NHS-POx) polymer was evaluated to determine hemostatic efficacy and long-term wound healing and adverse effects in a large animal model of parenchymal organ surgical bleeds. METHODS: Experiment 1 included 20 pigs that were treated with two NHS-POx patch prototypes [a gelatin fibrous carrier (GFC) with NHS-POx and an oxidized regenerated cellulose (ORC) with poly(lactic-co-glycolic acid)-NHS-POx:NU-POx (nucleophilically activated polyoxazoline)], a blank gelatin patch (GFC Blank), TachoSil® and Veriset™ to stop moderate liver and spleen punch bleedings. After various survival periods (1-6 weeks), pigs were re-operated to evaluate patch degradation and parenchymal healing. During the re-operation, experiment 2 was performed: partial liver and spleen resections with severe bleeding, and hemostatic efficacy was evaluated under normal and heparinized conditions of the two previous prototypes and one additional NHS-POx patch. In the third experiment an improved NHS-POx patch (GATT-Patch; GFC-NHS-POx and added 20% as nucleophilically activated polyoxazoline; NU-POx) was compared with TachoSil®, Veriset™ and GFC Blank on punch bleedings and partial liver and spleen resections for rapid (10s) hemostatic efficacy. RESULTS: NHS-POx-based patches showed better (GFC-NHS-POx 83.1%, ORC-PLGA-NHS-POx: NU-POx 98.3%) hemostatic efficacy compared to TachoSil® (25.0%) and GFC Blank (43.3%), and comparable efficacy with Veriset™ (96.7%) on moderate standardized punch bleedings on liver and spleen. All patches demonstrated gradual degradation over 6 weeks with a reduced local inflammation rate and an improved wound healing. For severe bleedings under non-heparinized conditions, hemostasis was achieved in 100% for Veriset™, 40% for TachoSil and 80-100% for the three NHS-POx prototypes; similar differences between patches remained for heparinized conditions. In experiment 3, GATT-Patch, Veriset™, TachoSil and GFC Blank reached hemostasis after 10s in 100%, 42.8%, 7.1% and 14.3%, respectively, and at 3 min in 100%, 100%, 14.3% and 35.7%, respectively, on all liver and spleen punctures and resections. CONCLUSIONS: NHS-POx-based patches, and particularly the GATT-Patch, are fast in achieving effective hemostatic sealing on standardized moderate and severe bleedings without apparent long-term adverse events.

Fabrication of a New Hyaluronic Acid/Gelatin Nanocomposite Hydrogel Coating on Titanium-Based Implants for Treating Biofilm Infection and Excessive Inflammatory Response.

Persistent inflammation caused by implant-associated biofilm infections has emerged as a significant clinical issue. While many methods have been developed to give implants great anti-biofilm benefits, the post-inflammatory microenvironment is frequently disregarded. Oxidative stress (OS) due to excessive reactive oxygen species (ROS) is considered to be one of the specific physiological signals of the inflammation microenvironment. Herein, ZIF-90-Bi-CeO2 nanoparticles (NPs) were incorporated into a Schiff-base chemically crosslinked hydrogel composed of aldehyde-based hyaluronic acid and gelatin. Through chemical crosslinking between polydopamine and gelatin, the hydrogel coating adhered to the Ti substrate. The modified Ti substrate gained multimodal antibacterial and anti-biofilm functions, which were attributed to the photothermal effect of Bi NPs, and the release of Zn ions and CeO2 NPs. Notably, CeO2 NPs endowed the system with dual-enzyme (SOD- and CAT-like) catalytic activities. In a rat implant-associated infection (IAI) model, the dual-functional hydrogel had a biofilm-removal ability and regulated OS and inflammatory responses to facilitate osseointegration. The photothermal therapy combined with a host inflammation-microenvironment regulation strategy might provide a novel treatment for biofilm infection and the accompanying excessive inflammation.

In Situ Formation of Injectable Gelatin Methacryloyl (GelMA) Hydrogels for Effective Intraocular Delivery of Triamcinolone Acetonide.

A novel drug delivery system designed for intraocular injection, gelatin methacryloyl (GelMA), has attracted much attention due to its sustained-release character and low cytotoxicity. We aimed to explore the sustained drug effect of GelMA hydrogels coupled with triamcinolone acetonide (TA) after injection into the vitreous cavity. The GelMA hydrogel formulations were characterized using scanning electron microscopy, swelling measurements, biodegradation, and release studies. The biological safety effect of GelMA on human retinal pigment epithelial cells and retinal conditions was verified by in vitro and in vivo experiments. The hydrogel exhibited a low swelling ratio, resistance to enzymatic degradation, and excellent biocompatibility. The swelling properties and in vitro biodegradation characteristics were related to the gel concentration. Rapid gel formation was observed after injection, and the in vitro release study confirmed that TA-hydrogels have slower and more prolonged release kinetics than TA suspensions. In vivo fundus imaging, optical coherence tomography measurements of retinal and choroid thickness, and immunohistochemistry did not reveal any apparent abnormalities of retinal or anterior chamber angle, and ERG indicated that the hydrogel had no impact on retinal function. The GelMA hydrogel implantable intraocular device exhibited an extended duration, in situ polymerization, and support cell viability, making it an attractive, safe, and well-controlled platform for treating the posterior segment diseases of the eye.

Pullulan-Based Hydrogels in Wound Healing and Skin Tissue Engineering Applications: A Review.

Wound healing is a complex process of overlapping phases with the primary aim of the creation of new tissues and restoring their anatomical functions. Wound dressings are fabricated to protect the wound and accelerate the healing process. Biomaterials used to design dressing of wounds could be natural or synthetic as well as the combination of both materials. Polysaccharide polymers have been used to fabricate wound dressings. The applications of biopolymers, such as chitin, gelatin, pullulan, and chitosan, have greatly expanded in the biomedical field due to their non-toxic, antibacterial, biocompatible, hemostatic, and nonimmunogenic properties. Most of these polymers have been used in the form of foams, films, sponges, and fibers in drug carrier devices, skin tissue scaffolds, and wound dressings. Currently, special focus has been directed towards the fabrication of wound dressings based on synthesized hydrogels using natural polymers. The high-water retention capacity of hydrogels makes them potent candidates for wound dressings as they provide a moist environment in the wound and remove excess wound fluid, thereby accelerating wound healing. The incorporation of pullulan with different, naturally occurring polymers, such as chitosan, in wound dressings is currently attracting much attention due to the antimicrobial, antioxidant and nonimmunogenic properties. Despite the valuable properties of pullulan, it also has some limitations, such as poor mechanical properties and high cost. However, these properties are improved by blending it with different polymers. Additionally, more investigations are required to obtain pullulan derivatives with suitable properties in high quality wound dressings and tissue engineering applications. This review summarizes the properties and wound dressing applications of naturally occurring pullulan, then examines it in combination with other biocompatible polymers, such chitosan and gelatin, and discusses the facile approaches for oxidative modification of pullulan.

A New Method to Determine Antioxidant Activities of Biofilms Using a pH Indicator (Resazurin) Model System.

Biopolymeric films were prepared with gelatin, plasticizer, and three different types of antioxidants (ascorbic acid, phytic acid, and BHA) corresponding to different mechanisms in activity. The antioxidant activity of films was monitored for 14 storage days upon color changes using a pH indicator (resazurin). The instant antioxidant activity of films was measured by a DPPH free radical test. The system using resazurin was composed of an agar, an emulsifier, and soybean oil to simulate a highly oxidative oil-based food system (AES-R). Gelatin-based films (GBF) containing phytic acid showed higher tensile strength and energy to break than all other samples due to the increased intermolecular interactions between phytic acid and gelatin molecules. The oxygen barrier properties of GBF films containing ascorbic acid and phytic acid increased due to the increased polarity, while GBF films containing BHA showed increased oxygen permeability compared to the control. According to "a-value" (redness) of the AES-R system tested with films, films incorporating BHA showed the most retardation of lipid oxidation in the system. This retardation corresponds to 59.8% antioxidation activity at 14 days, compared with the control. Phytic acid-based films did not show antioxidant activity, whereas ascorbic acid-based GBFs accelerated the oxidation process due to its prooxidant activity. The comparison between the DPPH free radical test and the control showed that the ascorbic acid and BHA-based GBFs showed highly effective free radical scavenging behavior (71.7% and 41.7%, respectively). This novel method using a pH indicator system can potentially determine the antioxidation activity of biopolymer films and film-based samples in a food system.

Abundant tannic acid modified gelatin/sodium alginate biocomposite hydrogels with high toughness, antifreezing, antioxidant and antibacterial properties.

The acidity of high tannic acid (TA) content solution can destroy the structure of protein, such as gelatin (G). This causes a big challenge to introduce abundant TA into the G-based hydrogels. Here, the G-based hydrogel system with abundant TA as hydrogen bonds provider was constructed by a "protective film" strategy. The protective film around the composite hydrogel was first formed by the chelation of sodium alginate (SA) and Ca2+. Subsequently, abundant TA and Ca2+ were successively introduced into the hydrogel system by immersing method. This strategy effectively protected the structure of the designed hydrogel. After treatment with 0.3 w/v TA and 0.06 w/v Ca2+ solutions, the tensile modulus, elongation at break and toughness of G/SA hydrogel increased about 4-, 2-, and 6-fold, respectively. Besides, G/SA-TA/Ca2+ hydrogels exhibited good water retention, anti-freezing, antioxidant, antibacterial properties and low hemolysis ratio. Cell experiments showed that G/SA-TA/Ca2+ hydrogels possessed good biocompatibility and could promote cell migration. Therefore, G/SA-TA/Ca2+ hydrogels are expected to be used in the field of biomedical engineering. The strategy proposed in this work also provides a new idea for improving the properties of other protein-based hydrogels.

Feasibility of gel-like radiopaque embolic material using gelatin sponge and contrast agent for tract embolization after percutaneous treatment.

OBJECTIVES: Tract embolization has been performed to prevent bleeding after trans-organ puncture. This study evaluated clinical outcomes of tract embolization using a gel-like radiopaque material comprising two sheets of gelatin sponge and 3 mL of contrast agent, and experimentally confirmed its viscosity and hemostatic efficacy. METHODS: Three study phases were planned. In a clinical setting, 57 consecutive patients who underwent tract embolization after transhepatic puncture were retrospectively analyzed. Clinical success was evaluated as absence of bleeding complications for 30 days after the procedure. In a basic experiment, viscosity of the material was analyzed. In an animal experiment, rabbit kidney puncture site was embolized via a 7-Fr sheath using this material, coils, or N-butyl-2-cyanoacrylate glue or received no embolization while removing the sheath. Amounts of tract bleeding were measured for 1 min and compared between groups. RESULTS: Embolization was successfully completed in all clinical cases. No postoperative bleeding requiring intervention was encountered. The basic experiment revealed the material was highly viscous. In the animal experiment, mean weights of bleeding in the control, gel-like embolic material, coil, and N-butyl-2-cyanoacrylate glue groups were 1.04±0.32 g, 0.080±0.056 g, 0.20±0.17 g and 0.11±0.10 g, respectively. No significant differences were seen among embolization groups, while the control group showed significantly more bleeding than any embolization group. CONCLUSION: Tract embolization with this gel-like radiopaque embolic material appears safe and feasible. ADVANCES IN KNOWLEDGE: Tract embolization using this embolic material with two sheets of gelatin sponge and 3 mL of contrast agent offers a safe, feasible, and economical procedure after trans-organ puncture, because the material offers the following characteristics: visibility under X-ray; viscosity facilitating retention in the tract; ability to allow repeated puncture via the same route; and low cost.

Low-dose erythromycin in pediatrics: Formulation and stability of 20 mg hard gelatin capsules.

OBJECTIVE: Erythromycin is a macrolide antibiotic that is also prescribed off-label in premature neonates as a prokinetic agent. There is no oral formulation with dosage and/or excipients adapted for these high-risk patients. METHODS: Clinical studies of erythromycin as a prokinetic agent were reviewed. Capsules of 20 milligrams of erythromycin were compounded with microcrystalline cellulose. Erythromycin capsules were analyzed using the chromatographic method described in the United States Pharmacopoeia which was found to be stability-indicating. The stability of 20 mg erythromycin capsules stored protected from light at room temperature was studied for one year. RESULTS: 20 mg erythromycin capsules have a beyond use date not lower than one year. CONCLUSION: 20 milligrams erythromycin capsules can be compounded in batches of 300 unities in hospital pharmacy with a beyond-use-date of one year at ambient temperature protected from light.

The model pH-controlled delivery system based on gelatin-tannin hydrogels containing ferrous ascorbate: iron releasein vitro.

Hydrogels have become an essential class among all biomaterials. The specialized biomaterials are highly valued in the field of biomedical applications. One of the problems in wound management is local microelement deficiency associated with extensive wound lesions. The significant lack of elemental iron in the human body leads to serious consequences and prolongs treatment. The synthesis of gelatin-tannin hydrogels with ion delivery function is proposed in this study. The ability to release ions in low acid solution is a sphere of great interest. The pH drop in the wound cavity is usually associated with the contamination of some bacterial cultures. pH-controlled delivery of iron in buffer solutions (рН = 5.5/6.4/7.4) was considered for these hydrogels. The kinetics of iron release was determined by visible spectroscopy. Theoretical models were applied to describe the process of ion delivery. The structure of materials was examined by IR-spectroscopy and demonstrated the incorporation of ferrous ascorbate into hydrogel matrix. Thermal analysis was used to point out the key differences in thermal behavior by isoconversional methods (Flynn-Wall-Ozawa/Kissinger-Akahira-Sunose). The mechanical properties of the materials have been studied. The effect of iron ascorbate on polymer network parameters was discussed. The current study demonstrated the possibility of obtaining gelatin-tannin hydrogels for pH-dependent iron delivery. That provides future perspectives to expand the set of releasing microelements for biomedical applications.

Evaluation of a transbronchial cryoprobe for the ablation of pulmonary nodules: an in vitro pilot study.

BACKGROUND: Ablation of malignant pulmonary nodules is a novel therapeutic option for patients who cannot undergo surgery. Current transthoracic approaches cause pneumothorax and/or bleeding in a significant number of cases. OBJECTIVE: Our purpose with this study was to evaluate cryoablation under in vitro conditions with a commercially available cryosurgery system. METHODS: We used ballistic gelatin to model the thermal conduction of lung tissue. The cryoprobe was inserted in the ballistic gelatin with two thermal sensors, they were placed 0.5 cm and 1.0. cm from the probe, respectively, temperature was measured on both sides. We used single-, double- and triple-freeze protocols to see if we could freeze it to -20 °C. RESULTS: We achieved - 18.6 ± 3.26 °C on the closer sensor (sensor 1) and - 3.7 ± 4.61 °C on the sensor further away (sensor 2) after 15 min using the single-freeze protocol. Using the dual-freeze protocol, we achieved - 23.2 ± 2,23 °C on sensor 1 and - 16.5 ± 2.82 °C on sensor 2. With the triple-freeze protocol we obtained - 23.5 ± 2.38 °C on sensor 1 and - 19.05 ± 3.22 °C on sensor 2. CONCLUSION: With dual-freeze, values above - 20 °C were achieved using nearer sensor data, but a plateau phase occurred as with continuous freezing. Using triple freeze, we reached - 20 °C at a distance of 0.5 cm from the probe, but not at 1 cm; therefore, we did not expand the diameter of the predicted necrosis zone.

Enzyme Conditioning of Chicken Collagen and Taguchi Design of Experiments Enhancing the Yield and Quality of Prepared Gelatins.

During the production of mechanically deboned chicken meat (MDCM), a by-product is created that has no adequate use and is mostly disposed of in rendering plants. Due to the high content of collagen, it is a suitable raw material for the production of gelatin and hydrolysates. The purpose of the paper was to process the MDCM by-product into gelatin by 3-step extraction. An innovative method was used to prepare the starting raw material for gelatin extraction, demineralization in HCl, and conditioning with a proteolytic enzyme. A Taguchi design with two process factors (extraction temperature and extraction time) was used at three levels (42, 46, and 50 °C; 20, 40, and 60 min) to optimize the processing of the MDCM by-product into gelatins. The gel-forming and surface properties of the prepared gelatins were analyzed in detail. Depending on the processing conditions, gelatins are prepared with a gel strength of up to 390 Bloom, a viscosity of 0.9-6.8 mPa·s, a melting point of 29.9-38.4 °C, a gelling point of 14.9-17.6 °C, excellent water- and fat-holding capacity, and good foaming and emulsifying capacity and stability. The advantage of MDCM by-product processing technology is a very high degree of conversion (up to 77%) of the starting collagen raw material to gelatins and the preparation of 3 qualitatively different gelatin fractions suitable for a wide range of food, pharmaceutical, and cosmetic applications. Gelatins prepared from MDCM by-product can expand the offer of gelatins from other than beef and pork tissues.

Acceleration of Electrospun PLA Degradation by Addition of Gelatin.

Biocompatible polyesters are widely used in biomedical applications, including sutures, orthopedic devices, drug delivery systems, and tissue engineering scaffolds. Blending polyesters with proteins is a common method of tuning biomaterial properties. Usually, it improves hydrophilicity, enhances cell adhesion, and accelerates biodegradation. However, inclusion of proteins to a polyester-based material typically reduces its mechanical properties. Here, we describe the physicochemical properties of an electrospun polylactic acid (PLA)-gelatin blend with a 9:1 PLA:gelatin ratio. We found that a small content (10 wt%) of gelatin does not affect the extensibility and strength of wet electrospun PLA mats but significantly accelerates their in vitro and in vivo decomposition. After a month, the thickness of PLA-gelatin mats subcutaneously implanted in C57black mice decreased by 30%, while the thickness of the pure PLA mats remained almost unchanged. Thus, we suggest the inclusion of a small amount of gelatin as a simple tool to tune the biodegradation behavior of PLA mats.

Gelatin as It Is: History and Modernity.

The data concerning the synthesis and physicochemical characteristics of one of the practically important proteins-gelatin, as well as the possibilities of its practical application, are systematized and discussed. When considering the latter, emphasis is placed on the use of gelatin in those areas of science and technology that are associated with the specifics of the spatial/molecular structure of this high-molecular compound, namely, as a binder for the silver halide photographic process, immobilized matrix systems with a nano-level organization of an immobilized substance, matrices for creating pharmaceutical/dosage forms and protein-based nanosystems. It was concluded that the use of this protein is promising in the future.

Tunable metacrylated silk fibroin-based hybrid bioinks for the bioprinting of tissue engineering scaffolds.

Three-dimensional (3D) bioprinting is a powerful technique for the production of tissue-like structures to study cell behavior and tissue properties. A major challenge in 3D extrusion bioprinting is the limited diversity of bioinks, which fulfills the requirements of shear-thinning and strain recovery behaviors and can be solidified by a crosslinking process to retain their shape after printing. Herein, we aimed to develop a natural biopolymer-based formula with dual crosslinking performance to formulate a cell-laden bioink. In this study, methacrylate gelatin (GelMA) and methacrylated silk fibroin (SFMA) with different degrees of methacrylation were fabricated into hybrid bioinks. The GelMA/SFMA bioink of an optimal degree provides excellent rheological properties for extrusion bioprinting, and its hydrogel precursor polymer can form a polymer network at a low temperature and the high shape fidelity of the printed construct through photocrosslinking. Moreover, the hydrogel bioink can encapsulate different types of cells together to create 3D printed constructs that mimic the cellular microenvironment at a microscale level. Human umbilical vein endothelial cells (HUVECs) and rat pheochromocytoma (PC12) cells encapsulated in the 3D printed constructs can maintain high viability and proliferation ability for a long time. Furthermore, the GelMA/SFMA hydrogels were implanted in the subcutaneous tissue of SD rats for the evaluation of biocompatibility and degradability in vivo. Thus, the proposed GelMA/SFMA bioink expands the palette of available bioinks and offers opportunities for biomedical applications such as tissue engineering and soft robotics in clinical applications.

[Antifriction and anti-wear performances of bionic lubricating fluid containing gelatin nanoparticles for artificial joint materials].

Objective: The antifriction and antiwear effects of gelatin nanoparticles (GLN-NP) on artificial joint materials in bionic joint lubricant were investigated to provide a theoretical basis for the development of new bionic joint lubricant. Methods: GLN-NP was prepared by cross-linking collagen acid (type A) gelatin with glutaraldehyde by acetone method, and the particle size and stability of GLN-NP were characterized. The biomimetic joint lubricants with different concentrations were prepared by mixing 5, 15, and 30 mg/mL GLN-NP with 15 and 30 mg/mL hyaluronic acid (HA), respectively. The friction reduction and antiwear effects of the biomimetic joint lubricants on zirconia ceramics were investigated on a tribometer. The cytotoxicity of each component of bionic joint lubricant on RAW264.7 mouse macrophages was evaluated by MTT assay. Results: The particle size of GLN-NP was about 139 nm, and the particle size distribution index was 0.17, showing a single peak, indicating that the particle size of GLN-NP was uniform. In complete culture medium, pH7.4 PBS, and deionized water at simulated body temperature, the particle size of GLN-NP did not change more than 10 nm with time, indicating that GLN-NP had good dispersion stability and did not aggregate. Compared with 15 mg/mL HA, 30 mg/mL HA, and normal saline, the friction coefficient, wear scar depth, width, and wear volume were significantly reduced by adding different concentrations of GLN-NP ( P<0.05); there was no significant difference between different concentrations of GLN-NP ( P>0.05). Biocompatibility test showed that the cell survival rate of GLN-NP, HA, and HA+GLN-NP solution decreased slightly with the increase of concentration, but the cell survival rate was more than 90%, and there was no significant difference between groups ( P>0.05). Conclusion: The bionic joint fluid containing GLN-NP has good antifriction and antiwear effect. Among them, GLN-NP saline solution without HA has the best antifriction and antiwear effect.

An Innovative Approach for Formulation of Rutin Tablets Targeted for Colon Cancer Treatment.

The aim of this study was the improvement of rutin solubility along with targeting its release to colon for effective treatment of colon cancer. Five formulations of compression-coated tablets were prepared with the same core composition including rutin-polyvinyl pyrrolidone K30 solid dispersion (rutin-PVP K30 SD) but differ in being coated with either frankincense alone or different combinations of frankincense with gelatin. The superior formula was selected based on the in vitro drug release then further evaluated in terms of physical properties and in vivo performance in dogs using X-ray. Moreover, in vitro cytotoxicity of rutin, rutin-PVP K30 SD, frankincense, and a mixture of rutin-PVP K30 SD with frankincense in a ratio representing their concentrations in the selected formula was assessed against human colon cancer (HCT-116) cell lines using sulforhodamine B assay. The formula (F4) with the coat consisted of 65%w/w frankincense and 35%w/w gelatin achieved acceptable in vitro controlled drug release. In vivo X-ray in dogs confirmed that F4 tablet could remain intact in the stomach and small intestine until reaching the colon. In vitro cytotoxicity revealed that mixture of rutin-PVP K30 SD with frankincense was more effective in arresting cancer cell growth than rutin or frankincense alone. Moreover, stability studies revealed that F4 tablets were physically and chemically stable. Thus, improving rutin solubility using solid dispersion technique and formulating it into frankincense-based compression-coated (F4) tablets would be a successful approach for colonic delivery of rutin with potential of improving therapeutic efficacy.

Graphene Oxide/Gelatin Nanofibrous Scaffolds Loaded with N-Acetyl Cysteine for Promoting Wound Healing.

Purpose: We aimed to develop an antioxidant dressing material with pro-angiogenic potential that could promote wound healing. Gelatin (Gel) was selected to improve the biocompatibility of the scaffolds, while graphene oxide (GO) was added to enhance their mechanical property. The loaded N-Acetyl cysteine (NAC) was performing the effect of scavenging reactive oxygen species (ROS) at the wound site. Materials and Methods: The physicochemical and mechanical properties, NAC releases, and biocompatibility of the NAC-GO-Gel scaffolds were evaluated in vitro. The regeneration capability of the scaffolds was systemically investigated in vivo using the excisional wound-splinting model in mice. Results: The NAC-GO-Gel scaffold had a stronger mechanical property and sustainer NAC release ability than the single Gel scaffold, which resulted in a better capacity for cell proliferation and migration. Mice wound-splinting models revealed that the NAC-GO-Gel scaffold effectively accelerated wound healing, promoted re-epithelialization, enhanced neovascularization, and reduced scar formation. Conclusion: The NAC-GO-Gel scaffold not only promotes wound healing but also reduces scar formation, showing a great potential application for the repair of skin defects.

Identification and Molecular Mechanism of Novel Immunomodulatory Peptides from Gelatin Hydrolysates: Molecular Docking, Dynamic Simulation, and Cell Experiments.

The purpose of this study was to identify donkey-hide gelatin-derived immunomodulatory peptides targeting Toll-like receptor 4-myeloid differentiation 2 (TLR4-MD2) and elucidate their binding modes using physicochemical property prediction, molecular docking, molecular dynamics simulations, and in vitro cell experiments. After hydrolyzing gelatin, 519 peptides were identified by liquid chromatography-tandem mass spectrometry. Peptides VQLSGEEK and GFSGLDGAKG bound to TLR4-MD2 with high binding affinity. In TLR4-MD2, Arg90, Ser118, Phe126, Tyr131, and Arg264 were key residues involved in the binding of these peptides. The RMSD and Rg values demonstrated that VQLSGEEK-TLR4-MD2 and GFSGLDGAKG-TLR4-MD2 complexes had stable and compact conformations. VQLSGEEK and GFSGLDGAKG were found to increase the cell viability and phagocytic activity of RAW264.7 macrophages; significantly promote the production of cytokines TNF-α, IL-1ß, and IL-6 in cells; and inhibit the overproduction of nitric oxide (NO) and cytokines in lipopolysaccharide (LPS)-induced RAW264.7 cells. Our results provided preliminary evidence that VQLSGEEK and GFSGLDGAKG could function as two-way immunomodulatory peptides with immunostimulatory and anti-inflammatory activities.

Adipose-derived stem cell spheroid-laden microbial transglutaminase cross-linked gelatin hydrogel for treating diabetic periodontal wounds and craniofacial defects.

BACKGROUND: Diabetes mellitus deteriorates the destruction and impairs the healing of periodontal wounds and craniofacial defects. This study is to evaluate the potential of self-assembled adipose-derived stem cell spheroids (ADsp) in microbial transglutaminase cross-linked gelatin hydrogel (mTG) for treating diabetic periodontal wounds and craniofacial defects. METHODS: Human adipose-derived stem cells (ADSCs) were isolated by lipoaspiration, pluripotent genes and trilineage differentiation were examined, and the maintenance of ADsp properties in mTG was verified. Oral mucosal wounds and calvarial osseous defects were created in diabetic rats. Gross observation, histologic evaluation, and immunohistochemistry for proliferating cells and keratinization were conducted in the mucosal wounds within 4-28 days. Micro-CT imaging, histologic evaluation, and immunohistochemistry for proliferating cells and osteogenic differentiation were conducted in the osseous defects at 7 and 28 days. RESULTS: ADSCs expressed pluripotent genes and were capable of trilineage differentiation. ADsp retained morphology and stemness in mTG. In diabetic mucosal wounds, wound closure, epithelization, and keratinization were accelerated in those with ADsp and ADsp-mTG. In diabetic osseous defects, osteogenic differentiation markers were evidently expressed, cell proliferation was promoted from day 7, and bone formation was significantly promoted at day 28 in those with osteogenically pretreated ADsp-mTG. CONCLUSIONS: ADsp-mTG accelerated diabetic oral mucosal wound healing, and osteogenically pretreated ADsp-mTG promoted diabetic osseous defect regeneration, proving that ADsp-mTG facilitated diabetic periodontal wound healing and craniofacial osseous defect regeneration.