BACKGROUND: Reconstruction of large eyelid defects remains challenging due to the lack of suitable eyelid tarsus tissue substitutes. We aimed to evaluate a novel bioengineered chitosan scaffold for use as an eyelid tarsus substitute.METHODS: Three-dimensional macroporous chitosan hydrogel scaffold were produced via cryogelation with specific biomechanical properties designed to directly match characteristics of native eyelid tarsus tissue. Scaffolds were characterized by confocal microscopy and tensile mechanical testing. To optimise biocompatibility, human eyelid skin fibroblasts were cultured from biopsy-sized samples of fresh eyelid skin. Immunological and gene expression analysis including specific fibroblast-specific markers were used to determine the rate of fibroblast de-differentiation in vitro and characterize cells cultured. Eyelid skin fibroblasts were then cultured over the chitosan scaffolds and the resultant adhesion and growth of cells were characterized using immunocytochemical staining.RESULTS: The chitosan scaffolds were shown to support the attachment and proliferation of NIH 3T3 mouse fibroblasts and human orbital skin fibroblasts in vitro. Our novel bioengineered chitosan scaffold has demonstrated biomechanical compatibility and has the ability to support human eyelid skin fibroblast growth and proliferation.CONCLUSIONS: This bioengineered tissue has the potential to be used as a tarsus substitute during eyelid reconstruction, offering the opportunity to pre-seed the patient's own cells and represents a truly personalised approach to tissue engineering.
Animals ; Ankle ; Chitosan ; Cryogels ; Eyelids ; Fibroblasts ; Gene Expression ; Humans ; Hydrogel ; In Vitro Techniques ; Mice ; Microscopy, Confocal ; Orbit ; Skin ; Tissue Engineering

The biocompatible hydrogel was fabricated under suitable conditions with natural dextran and polyethylene glycol (PEG) as the reaction materials. The oligomer (Dex-AI) was firstly synthesized with dextran and allylisocyanate (AI). This Dex-AI was then reacted with poly (ethyleneglycoldiacrylate) (PEGDA) under the mass ratio of 4∶6 to get hydrogel (DP) with the maximum water absorption of 810%. This hydrogel was grafted onto the surface of medical catheter via diphenyl ketone treatment under ultraviolet (UV) initiator. The surface contact angle became lower from (97 ± 6.1)° to (25 ± 4.2)° after the catheter surface was grafted with hydrogel DP, which suggests that the catheter possesses super hydrophilicity with hydrogel grafting. The evaluation after they were implanted into ICR rats subcutaneously verified that this catheter had less serious inflammation and possessed better histocompatibility comparing with the untreated medical catheter. Therefore, it could be concluded that hydrogel grafting is a good technology for patients to reduce inflammation due to catheter implantation, esp. for the case of retention in body for a relative long time.
Allyl Compounds ; Animals ; Biocompatible Materials ; Catheters ; Dextrans ; Hydrogel, Polyethylene Glycol Dimethacrylate ; Hydrogels ; Hydrophobic and Hydrophilic Interactions ; Isocyanates ; Polyethylene Glycols ; Rats ; Water

BACKGROUND: Despite the development of progressive surgical techniques and antibiotics, osteomyelitis is a big challenge for orthopedic surgeons. The main aim of this study is to fabricate an in situ gelling hydrogel that permits sustained release of antibiotic (for control of infection) and growth factor (for induction of new bone formation) for effective treatment of osteomyelitis. METHODS: An in situ gelling alginate (ALG)/hyaluronic acid (HA) hydrogel containing vancomycin (antibiotic) and bone morphogenetic protein-2 (BMP-2; growth factor) was prepared by simple mixing of ALG/HA/Na₂HPO₄ solution and CaSO₄/vancomycin/BMP-2 solution. The release behaviors of vancomycin and BMP-2, anti-bacterial effect (in vitro); and therapeutic efficiency for osteomyelitis and bone regeneration (in vivo, osteomyelitis rat model) of the vancomycin and BMP-2-incorporated ALG/HA hydrogel were investigated. RESULTS: The gelation time of the ALG/HA hydrogel was controlled into approximately 4 min, which is sufficient time for handling and injection into osteomyelitis lesion. Both vancomycin and BMP-2 were continuously released from the hydrogel for 6 weeks. From the in vitro studies, the ALG/HA hydrogel showed an effective anti-bacterial activity without significant cytotoxicity for 6 weeks. From an in vivo animal study using Sprague-Dawley rats with osteomyelitis in femur as a model animal, it was demonstrated that the ALG/HA hydrogel was effective for suppressing bacteria (Staphylococcus aureus) proliferation at the osteomyelitis lesion and enhancing bone regeneration without additional bone grafts. CONCLUSIONS: From the results, we suggest that the in situ gelling ALG/HA hydrogel containing vancomycin and BMP-2 can be a feasible therapeutic tool to treat osteomyelitis.
Animals ; Anti-Bacterial Agents ; Bacteria ; Bone Regeneration ; Femur ; Hydrogel ; In Vitro Techniques ; Orthopedics ; Osteomyelitis ; Rats ; Rats, Sprague-Dawley ; Surgeons ; Transplants ; Vancomycin

Polyacrylamide hydrogel (PAAG) was developed in the 1980s as an injectable filler for breast augmentation and tissue contour improvement, but its potential risk for oncogenesis and the frequent occurrence of chronic complications after injections led to the prohibition of its further use as an injectable material. Although breast augmentation with PAAG injections was mostly performed in China and Eastern Europe, the migration of patients and long-term complications of the procedure made it a global concern. Herein, we describe the case of a 49-year-old woman who immigrated to Korea after undergoing breast augmentation via PAAG injection in China, and complained of persistent mastodynia and retraction of both breasts. Surgical treatment was undertaken, along with removal of the PAAG and total capsulectomy of the fibrous capsule containing the gel through an inframammary fold incision. We share our experience of diagnosing and treating this case, and present a literature review.
Breast ; Carcinogenesis ; China ; Europe, Eastern ; Female ; Humans ; Hydrogel ; Korea ; Mastodynia ; Middle Aged ; Pregnancy-Associated alpha 2-Macroglobulins

The removal of fillers used for soft-tissue augmentation is an issue of concern, as the possible need for extensive surgery to remove fillers deters their use by many surgeons. Several studies have demonstrated the safety and efficacy of polyacrylamide hydrogel (Aquamid) gel, but to date no report has described its removal after 10 years. Here, we report a case of Aquamid removal. A 33-year-old woman, who had undergone forehead augmentation 12 years previously with an Aquamid injection, visited the department of plastic and reconstructive surgery of our medical center due to a severe forehead contour irregularity. Removal of 20 mL of excess gel was performed by direct incision and squeezing under local anesthesia. Our experience shows that Aquamid removal is possible, but should be performed with appropriate surgical precautions.
Adult ; Anesthesia, Local ; Dermal Fillers ; Female ; Forehead ; Humans ; Hydrogel ; Plastics ; Surgeons

BACKGROUND: Currently, dermal fillers need to be 25 µm or larger to reduce in vivo degradation by macrophages. However, the large size of fillers may cause side effects, including interruption of blood flow and nodule formation. Therefore, using rats, we tested a polycaprolactone copolymer hydrogel with nanoscale particles that could maintain a low in vivo degradation rate. METHODS: Thirty-six 6-week-old Sprague-Dawley rats were divided into group A (normal saline), group B (polycaprolactone microsphere filler), and group C (polycaprolactone copolymer nanosphere hydrogel). The corresponding materials were injected into the dermal layer of the scalp of the rats. At 4, 8, and 12 weeks after injection, blood biochemical and kidney and liver histological analyses were performed. Tissues were examined using hematoxylin-eosin staining to observe tissue infiltration of materials. Collagen formation in the dermal tissue of the scalp was observed with Masson trichrome staining and the collagen content was quantified using a soluble collagen assay kit. RESULTS: The histologic examination for organ infiltration showed no abnormal findings. All blood test results were within the normal ranges. The amount of collagen at 12 weeks increased by 1.22 mg/g in group C and by 0.6 mg/g in group B. CONCLUSIONS: The results reveal that the nanosphere complex near the injection site induced collagen formation. Regardless of the sphere size, aggregation of the copolymer prevented macrophage phagocytosis. The polycaprolactone copolymer nanosphere hydrogel was effective for more than 3 months when injected in the scalp dermal tissue of Sprague-Dawley rats and can be used safely.
Animals ; Collagen ; Dermal Fillers ; Hematologic Tests ; Hydrogel ; Kidney ; Liver ; Macrophages ; Microspheres ; Nanospheres ; Phagocytosis ; Rats ; Rats, Sprague-Dawley ; Reference Values ; Scalp

STUDY DESIGN: Prospective pilot study OBJECTIVES: The efficacy and safety of ‘PF-72’ for management of postoperative acute pain through a mixed ‘PF-72’ and 0.75% ropivacaine hydrochloride solution in patients with posterior spine surgery was evaluated as ‘0.75% ropivacaine’ and ‘untreated’ controls. SUMMARY OF LITERATURE REVIEW: Postoperative acute pain is major surgical side effect that lead to the deterioration of the quality of life. Traditional pain control results in variable side effects, and multimodal pain management has been recommended as an alternative. Local anesthetics is a short-acting time lower than 12 hours. There is controversy about the efficiency and stability of thermoreactive hydrogel products as a drug delivery system. MATERIALS AND METHODS: Patients scheduled for posterior spine surgery were enrolled by the inclusion criteria. In the treated group, PF-72 and ropivacaine mixture was injected to the surgical wound before closure. In control group 1, only 0.75% ropivacaine hydrochloride was injected. In the control group 2, the surgical site was without injection. Ten patients were randomly assigned to each group and standardized drugs for pain control were applied postoperatively and rescue regimens were applied when necessary. Postoperative pain score and the cumulative area under the curve (AUC) of pain score were compared. The percentage of subjects who were painless (pain score ≤ 3) was examined at each observation point. The first time of injection and the total dose of the rescue regimen were examined. Postoperative nausea and vomiting (PONV) were also evaluated. RESULTS: There was no significant difference in demographic data. The sum AUC of pain scores in the treated group was significantly lower than that in the control group 1 and 2 at all observation times. The proportion of painless patients was significantly higher in the treated group than in the control group 2. There was no significant difference between the first administration time and the total usage of the rescue regimen, and the percentage of patients with PONV at all time points. There was no statistically significant difference in the incidence of adverse events. CONCLUSIONS: PF-72 and ropivacaine mixture showed significant effects for pain management up to 72 hours postoperatively for the patients who underwent posterior spinal surgery without fatal complications.
Acute Pain ; Anesthetics, Local ; Area Under Curve ; Drug Delivery Systems ; Humans ; Hydrogel ; Incidence ; Pain Management ; Pain, Postoperative ; Pilot Projects ; Postoperative Nausea and Vomiting ; Prospective Studies ; Quality of Life ; Spine ; Wounds and Injuries

BACKGROUND: Ice cooling vests can cause tissue damage and have no flexibility. Therefore, these two undesirable properties of ice cooling vest were optimized, and the present study was aimed to compare the impact of the optimized ice cooling vest and a commercial paraffin cooling vest on physiological and perceptual strain under controlled conditions. METHODS: For optimizing, hydrogel was used to increase the flexibility and a layer of the ethylene vinyl acetate foam was placed into the inside layer of packs to prevent tissue damage. Then, 15 men with an optimized ice cooling vest, with a commercial paraffin cooling vest, and without a cooling vest performed tests including exercise on a treadmill (speed of 2.8 km/hr and slope of %0) under hot (40℃) and dry (40 %) condition for 60 min. The physiological strain index and skin temperature were measured every 5 and 15 minutes, respectively. The heat strain score index and perceptual strain index were also assessed every 15 minutes. RESULTS: The mean values of the physiological and perceptual indices differed significantly between exercise with and without cooling vests (P < 0.05). However, the difference of the mean values of the indices except the value of the skin temperature during the exercises with the commercial paraffin cooling vest and the optimized ice cooling vest was not significant (P > 0.05). CONCLUSIONS: The optimized ice cooling vest was as effective as the commercial paraffin cooling vest to control the thermal strain. However, ice has a greater latent heat and less production cost.
Exercise ; Hot Temperature ; Humans ; Hydrogel ; Ice ; Male ; Paraffin ; Pliability ; Skin Temperature

PURPOSE: To determine whether the swelling and mechanical properties of osmotic self-inflating expanders allow or not the induction of intraoral soft tissue expansion in dogs. METHODS: Three different volumes (0.15, 0.25, and 0.42 mL; referred to respectively as the S, M, and L groups) of soft tissue expanders (STEs) consisting of a hydrogel core coated with a silicone-perforated membrane were investigated in vitro to assess their swelling behavior (volume swelling ratio) and mechanical properties (tensile strength, tensile strain). For in vivo investigations, the STEs were subperiosteally inserted for 4 weeks in dogs (n=5). Soft tissue expansion was clinically monitored. Histological analyses included the examination of alveolar bone underneath the expanders and thickness measurements of the surrounding fibrous capsule. RESULTS: The volume swelling ratio of all STEs did not exceed 5.2. In tensile mode, the highest mean strain was registered for the L group (98.03±0.3 g/cm), whereas the lowest mean value was obtained in the S group (81.3±0.1 g/cm), which was a statistically significant difference (P < 0.05). In addition, the S and L groups were significantly different in terms of tensile strength (1.5±0.1 g/cm for the S group and 2.2±0.1 g/cm for the L group, P < 0.05). Clinical monitoring showed successful dilatation of the soft tissues without signs of inflammation up to 28 days. The STEs remained volumetrically stable, with a mean diameter in vivo of 6.98 mm, close to the in vitro post-expansion findings (6.69 mm). Significant histological effects included highly vascularized collagen-rich fibrous encapsulation of the STEs, with a mean thickness of 0.67±0.12 mm. The bone reaction consisted of resorption underneath the STEs, while apposition was observed at their edges. CONCLUSIONS: The swelling and mechanical properties of the STEs enabled clinically successful soft tissue expansion. A tissue reaction consisting of fibrous capsule formation and bone loss were the main histological events.
Alveolar Ridge Augmentation ; Animals ; Dilatation ; Dogs ; Hydrogel ; In Vitro Techniques ; Inflammation ; Membranes ; Tensile Strength ; Tissue Expansion ; Tissue Expansion Devices

In this study, for better understanding of patient-derived xenograft (PDX) generation, angiogenic characteristics during PDX cancerous tissue generation was investigated with different initial cell seeding conditions in the hydrogel. We monitored the angiogenic changes during the formation of in vivo cancer cell line xenografts induced by endothelial cells. Our in vivo cancer tissue formation system was designed with the assistance of tissue engineering technology to mimic patient-derived xenograft formation. Endothelial cells and MIA PaCa-2 pancreatic carcinoma cells were encapsulated in fibrin gel at different mixing configurations and subcutaneously implanted into nude mice. To investigate the effect of the initial cancerous cell distribution in the fibrin gel, MIA PaCa-2 cells were encapsulated as a homogeneous cell distribution or as a cell aggregate, with endothelial cells homogeneously distributed in the fibrin gel. Histological observation of the explanted tissues after different implantation periods revealed three different stages: isolated vascular tubes, leaky blood vessels, and mature cancerous tissue formation. The in vivo engineered cancerous tissues had leaky blood vessels with low expression of the vascular tight junction marker CD31. Under our experimental conditions, complex cancer-like tissue formation was most successful when tumorous cells and endothelial cells were homogeneously mixed in the fibrin gel. The present study implies that tumorous xenograft tissue formation can be achieved with a low number of initial cells and that effective vascularization conditions can be attained with a limited volume of patient-derived cancer tissue. Endothelial cell-assisted vascularization can be a potent choice for the effective development of vascularized cancerous tissues for studying patient-derived xenografts, cancer angiogenesis, cancer metastasis, and anticancer drugs.
Animals ; Blood Vessels ; Cell Line ; Endothelial Cells ; Fibrin ; Heterografts* ; Hydrogel ; Mice ; Mice, Nude ; Neoplasm Metastasis ; Pancreatic Neoplasms* ; Tight Junctions ; Tissue Engineering