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: 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

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: The interplay between neurogenesis and angiogenesis is crucial during the development mediated by neuro-angiogenic morphogens. In particular, the angiogenic activity of neuropeptides and their role in tissue regeneration have long been investigated for better understanding of their biological mechanisms and further applications. However, there have been few studies for direct comparison of angiogenic activities of neuropeptides for in vitro and in vivo models. In this study, we report that direct comparison of the angiogenic activities of neuropeptide Y, secretoneurin, and substance P (SP) immobilized on hydrogels in in vitro and in vivo experiments. METHODS: A hyaluronic acid-based hydrogel is prepared by utilizing acrylated hyaluronic acid and thiolated peptides as a crosslinker and angiogenic factors, respectively. Angiogenic activities of three neuropeptides are evaluated not only by in vitro angiogenic and gene expression assays, but also by an in vivo chronic myocardial infarction model. RESULTS: The comparison of in vitro angiogenic activities of three peptides demonstrates that the SP-immobilized hydrogel shows a higher degree of cell network formation and angiogenic-specific genes than those of the other peptides and the control case. In addition, a three-dimensional angiogenic assay illustrates that more sprouting is observable in the SP group. Evaluation of regenerative activity in the chronic myocardial infarction model reveals that all three peptideimmobilized hydrogels induce increased cardiac function as well as structural regeneration. Among all the cases, the SP group provided the highest regenerative activity both in vitro and in vivo. CONCLUSION: In our comparison study, the SP-immobilized hydrogel shows the highest angiogenic activity and tissue regeneration among the test groups. This result suggests that nerve regeneration factors help angiogenesis in damaged tissues, which also highlights the importance of the neuro-angiogenic peptides as an element of tissue regeneration.
Angiogenesis Inducing Agents ; Gene Expression ; Hyaluronic Acid ; Hydrogel ; Hydrogels ; In Vitro Techniques ; Myocardial Infarction* ; Nerve Regeneration ; Neurogenesis ; Neuropeptide Y* ; Neuropeptides* ; Peptides ; Regeneration ; Substance P*

BACKGROUND: The fabrication of microchannels in hydrogel can facilitate the perfusion of nutrients and oxygen, which leads to guidance cues for vasculogenesis. Microchannel patterning in biomimetic hydrogels is a challenging issue for tissue regeneration because of the inherent low formability of hydrogels in a complex configuration. We fabricated microchannels using wire network molding and immobilized the angiogenic factors in the hydrogel and evaluated the vasculogenesis in vitro and in vivo. METHODS: Microchannels were fabricated in a hyaluronic acid-based biomimetic hydrogel by using “wire network molding” technology. Substance P was immobilized in acrylated hyaluronic acid for angiogenic cues using Michael type addition reaction. In vitro and in vivo angiogenic activities of hydrogel with microchannels were evaluated. RESULTS: In vitro cell culture experiment shows that cell viability in two experimental biomimetic hydrogels (with microchannels and microchannels + SP) was higher than that of a biomimetic hydrogel without microchannels (bulk group). Evaluation on differentiation of human mesenchymal stem cells (hMSCs) in biomimetic hydrogels with fabricated microchannels shows that the differentiation of hMSC into endothelial cells was significantly increased compared with that of the bulk group. In vivo angiogenesis analysis shows that thin blood vessels of approximately 25–30 µm in diameter were observed in the microchannel group and microchannel + SP group, whereas not seen in the bulk group. CONCLUSION: The strategy of fabricating microchannels in a biomimetic hydrogel and simultaneously providing a chemical cue for angiogenesis is a promising formula for large-scale tissue regeneration.
Angiogenesis Inducing Agents ; Biomimetics* ; Blood Vessels ; Cell Culture Techniques ; Cell Survival ; Cues ; Endothelial Cells ; Fungi ; Humans ; Hyaluronic Acid ; Hydrogel* ; Hydrogels* ; In Vitro Techniques ; Mesenchymal Stromal Cells ; Oxygen ; Perfusion ; Regeneration ; Substance P