Antifouling Properties of Amine-Oxide-Containing Zwitterionic Polymers.

Biofouling due to nonspecific proteins or cells on the material surfaces is a major challenge in a range of applications such as biosensors, medical devices, and implants. Even though poly(ethylene glycol) (PEG) has become the most widely used stealth material in medical and pharmaceutical products, the number of reported cases of PEG-triggered rare allergic responses continues to increase in the past decades. Herein, a new type of antifouling material poly(amine oxide) (PAO) has been evaluated as an alternative to overcome nonspecific foulant adsorption and impart comparable biocompatibility. Alkyl-substituted PAO containing diethyl, dibutyl, and dihexyl substituents are prepared, and their solution properties are studied. Photoreactive copolymers containing benzophenone as the photo-cross-linker are prepared by reversible addition-fragmentation chain-transfer polymerization and fully characterized by gel permeation chromatography and dynamic light scattering. Then, these water-soluble polymers are anchored onto a silicon wafer with the aid of UV irradiation. By evaluating the fouling resistance properties of these modified surfaces against various types of foulants, protein adsorption and bacterial attachment assays show that the cross-linked PAO-modified surface can efficiently inhibit biofouling. Furthermore, human blood cell adhesion experiments demonstrate that our PAO polymer could be used as a novel surface modifier for biomedical devices.

Extracellular Matrix Protein Coating of Processed Fish Scales Improves Human Corneal Endothelial Cell Adhesion and Proliferation.

PURPOSE: Corneal transplantation can treat corneal endothelial diseases. Implanting cultivated human corneal endothelial cells (HCECs) via a cell carrier has clinical value as an alternative therapeutic strategy. This study was performed to compare the feasibility of fish scales and other biomaterials (gelatin and chitosan) as cell carriers and to investigate the effects of an extracellular matrix (ECM) protein coating to improve the cytocompatibility of fish scales. METHODS: The physical properties of gelatin, chitosan, and fish scales were compared. Immortalized HCECs (B4G12) were cultured on processed fish scales, which were coated with fibronectin, laminin, collagen IV, or FNC Coating Mix. Cell attachment and proliferation were evaluated by immunofluorescence, cell counting, and bromodeoxyuridine (BrdU) labeling assays. Immunoblots were used to examine the expression levels of integrin-linked kinase (ILK), phosphate-ILK, ß-catenin, p63, and cell cycle mediators (cyclin D1 and p27Kip1). RESULTS: The transparency of processed fish scales was better than that of chitosan, while the strength was higher than that of gelatin. The laminin, collagen IV, and FNC coatings facilitated B4G12 cell adhesion and proliferation, while fibronectin only facilitated cell adhesion. The laminin, collagen IV, and FNC coatings also upregulated phosphate-ILK and p63 expression. In addition, the FNC coating activated cell cycle mediators. CONCLUSION: ECM protein-coated processed fish scales can serve as a novel cell carrier to facilitate the development of HCEC transplantation. TRANSLATIONAL RELEVANCE: Improving the physical properties and cytocompatibility of fish scales as a cell carrier will facilitate the transplantation of HCECs into corneas for the purpose of cell therapy.

Learning curve of image-guided video-assisted thoracoscopic surgery for small pulmonary nodules: A prospective analysis of 30 initial patients.

OBJECTIVES: The use of image-guided video-assisted thoracoscopic surgery for simultaneous localization and removal of small solitary pulmonary nodules in a hybrid operation room using C-arm cone-beam computed tomography is gaining momentum. We sought to assess the effect of the learning curve on procedural parameters and clinical outcomes of image-guided video-assisted thoracoscopic surgery for treating patients with small solitary pulmonary nodules. METHODS: Clinical variables and treatment outcomes of the 30 initial patients with solitary pulmonary nodules who were treated with image-guided video-assisted thoracoscopic surgery at Chang Gung Memorial Hospital (Taiwan) were prospectively analyzed. Two sequential groups (groups I and II, n = 15 each) were compared with regard to localization time, radiation doses, and success rates. We used the Pearson's correlation coefficient to investigate the association between the surgical experience and the procedural time. RESULTS: In the entire cohort, the median size of solitary pulmonary nodules on preoperative computed tomography images was 6 mm (interquartile range, 4.5-9 mm), and their median distance from the pleural surface was 10 mm (interquartile range, 5-15 mm). The median tumor depth-to-size ratio was 1.4 (interquartile range, 0.7-2.5). The clinical parameters were similar between the 2 groups. There was an inverse association between the surgical experience and the procedural time (Pearson's r = -0.6873; P < .001). A significant reduction in localization time (median, 24 vs 49 minutes, respectively; P < .001) and radiation exposure (median, 70.7 vs 224 mGy, respectively; P < .001) was noted in group II (late patients) compared with group I (early patients). Notably, the success rates in groups II and I were similar (93.3% vs 86.7%, respectively; P = . 876). CONCLUSIONS: Our data demonstrate a significant learning curve for image-guided video-assisted thoracoscopic surgery in the treatment of solitary pulmonary nodules as evidenced by decreased localization time and radiation exposure occurring with increased surgical experience.

Single-stage localization and removal of small lung nodules through image-guided video-assisted thoracoscopic surgery.

OBJECTIVES: This case series illustrates the feasibility of single-stage image-guided video-assisted thoracoscopic surgery for simultaneous localization and removal of small solitary pulmonary nodules (SPNs). The procedure was performed in a hybrid operating room using C-arm cone-beam computed tomography equipped with a laser-guided navigation system. METHODS: Between October 2016 and January 2017, 12 consecutive patients presenting with SPNs underwent image-guided video-assisted thoracoscopic surgery. The feasibility and safety of the procedure were assessed through a retrospective review of the patients' clinical charts. RESULTS: The median size of SPNs was 5.5 mm [interquartile range (IQR) 4-6 mm], whereas their median distance from the pleural surface was 11.7 mm (IQR 6-11.3 mm). All of the lesions were visible on intraoperative C-arm cone-beam computed tomography images, and localization was successful in 10 patients; thereafter, complete thoracoscopic resection was successfully performed. The median time required for the localization of SPNs was 45.5 min (IQR 36-60 min), whereas the median radiation exposure (expressed through the skin absorbed dose) was 223.2 mGy (IQR 180.3-321.3 mGy). Lesion localization was unsuccessful in 2 cases because to the development of pneumothorax induced by needle puncture. In such cases, a utility thoracotomy was required for the identification of SPNs. There was no operative mortality, and the median length of postoperative stay was 4 days (IQR 3.8-4 days). CONCLUSIONS: The results of our case series support the feasibility of image-guided video-assisted thoracoscopic surgery for detection and removal of SPNs. Future efforts should be tailored to decrease localization time and minimize radiation exposure.

Targeting efficiency and biodistribution of biotinylated-EGF-conjugated gelatin nanoparticles administered via aerosol delivery in nude mice with lung cancer.

Lung cancer is the most malignant cancer today; in order to develop an effective drug delivery system for lung cancer therapy, gelatin nanoparticles (GPs) were modified with NeutrAvidin(FITC)-biotinylated epidermal growth factor (EGF) to form EGF receptor (EGFR)-seeking nanoparticles (GP-Av-bEGF). Aerosol droplets of the GP-Av-bEGF were generated by using a nebulizer and were delivered to mice model of lung cancer via aerosol delivery. Analysis of the aerosol size revealed that 99% of the nanoparticles after nebulization had a mass median aerodynamic diameter (MMAD) within the suitable range (0.5-5 microm) for lower airway deposition. The safety of inhaled nanoparticles was examined by lung edema and myeloperoxidase (MPO) activity assay. There's no finding suggestive of acute lung inflammation following inhalation. The fluorescence images obtained from live mice showed that the GP-Av-bEGF could target the cancerous lungs in a more specific manner. Fluorescence analysis of the organs revealed that the GP-Av-bEGF was mainly distributed in cancerous lungs. In contrast, nanoparticle accumulation was lower in normal lungs. The histological results indicated that the fluorescent GP-Av-bEGF was colocalized with the anti-EGFR-immunostain due to EGFR binding. The results of this study revealed that GP-Av-bEGF could target to the EGFR-overexpression cancer cells in vivo and may prove to be beneficial drug carriers when administered by simple aerosol delivery for the treatment of lung cancer.

TGF-beta1 immobilized tri-co-polymer for articular cartilage tissue engineering.

Tri-co-polymer with composition of gelatin, hyaluronic acid and chondroitin-6-sulfate has been used to mimic the cartilage extracellular matrix as scaffold for cartilage tissue engineering. In this study, we try to immobilize TGF-beta1 onto the surface of the tri-co-polymer sponge to suppress the undesired differentiation during the cartilage growth in vitro. The scaffold was synthesized with a pore size in a range of 300-500 microm. TGF-beta1 was immobilized on the surface of the tri-co-polymer scaffold with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) as a crosslinking agent. Tri-co-polymer scaffolds with and without TGF-beta1 were seeded with porcine chondrocytes and cultured in a spinner flask for 2, 4, and 6 weeks. The chondrocytes were characterized by the methods of immunohistochemical staining with anti-type II collagen and anti-S-100 protein monoclonal antibody, and RT-PCR. After culturing for 4 weeks, chondrocytes showed positive in S-100 protein, Alcian blue, and type II collagen for the scaffold with TGF-beta1 immobilization. There is no observed type I and type X collagen expression in the scaffolds from the observation of RT-PCR. In addition, the scaffold without TGF-beta1 immobilization, type X collagen, can be detected after cultured for 2 weeks. Type I collagen was progressively expressed after 4 weeks. These results can conclude that TGF-beta1 immobilized scaffold can suppress chondrocytes toward prehypertrophic chondrocytes and osteolineage cells. The tri-co-polymer sponge with TGF-beta1 immobilization should have a great potential in cartilage tissue engineering in the future.

Tissue engineering-based cartilage repair with allogenous chondrocytes and gelatin-chondroitin-hyaluronan tri-copolymer scaffold: a porcine model assessed at 18, 24, and 36 weeks.

We previously showed that cartilage tissue can be engineered in vitro with porcine chondrocytes and gelatin/chondoitin-6-sulfate/hyaluronan tri-copolymer which mimic natural cartilage matrix for use as a scaffold. In this animal study, 15 miniature pigs were used in a randomized control study to compare tissue engineering with allogenous chondrocytes, autogenous osteochondral (OC) transplantation, and spontaneous repair for OC articular defects. In another study, 6 pigs were used as external controls in which full thickness (FT) and OC defects were either allowed to heal spontaneously or were filled with scaffold alone. After exclusion of cases with infection and secondary arthritis, the best results were obtained with autogenous OC transplantation, except that integration into host cartilage was poor. The results for the tissue engineering-treated group were satisfactory, the repair tissue being hyaline cartilage and/or fibrocartilage. Spontaneous healing and filling with scaffold alone did not result in good repair. With OC defects, the subchondral bone plate was not restored by cartilage tissue engineering. These results show that tri-copolymer can be used in in vivo cartilage tissue engineering for the treatment of FT articular defects.

Cartilage tissue engineering on the surface of a novel gelatin-calcium-phosphate biphasic scaffold in a double-chamber bioreactor.

Tissue engineering is a new approach to articular cartilage repair; however, the integration of the engineered cartilage into the host subchondral bone is a major problem in osteochondral injury. The aim of the present work, therefore, was to make a tissue-engineered osteochondral construct from a novel biphasic scaffold in a newly designed double-chamber bioreactor. This bioreactor was designed to coculture chondrocytes and osteoblasts simultaneously. The aim of this study was to prove that engineered cartilage could be formed with the use of this biphasic scaffold. The scaffold was constructed from gelatin and a calcium-phosphate block made from calcined bovine bone. The cartilage part of the scaffold had a uniform pore size of about 180 microm and approximate porosity of 75%, with the trabecular pattern preserved in the bony part of the scaffold. The biphasic scaffolds were seeded with porcine chondrocytes and cultured in a double-chamber bioreactor for 2 or 4 weeks. The chondrocytes were homogeneously distributed in the gelatin part of the scaffold, and secretion of the extracellular matrix was demonstrated histologically. The chondrocytes retained their phenotype after 4 weeks of culture, as proven immunohistochemically. After 4 weeks of culture, hyaline-like cartilage with lacuna formation could be clearly seen in the gelatin scaffold on the surface of the calcium phosphate. The results show that this biphasic scaffold can support cartilage formation on a calcium-phosphate surface in a double-chamber bioreactor, and it seems reasonable to suggest that there is potential for further application in osteochondral tissue engineering.

Gelatin-chondroitin-hyaluronan tri-copolymer scaffold for cartilage tissue engineering.

The mechanism by which the cell synthesizes and secretes extracellular matrix (ECM) and is, in turn, regulated by the ECM is termed dynamic reciprocity. The aim of the present work was to produce a gelatin/chondoitin-6-sulfate/hyaluronan tri-copolymer to mimic natural cartilage matrix for use as a scaffold for cartilage tissue engineering. The scaffold produced had a uniform pore size of about 180 microm and adequate porosity of 75%. Porcine chondrocytes were seeded onto the tri-copolymer scaffold and cultured in Petri dishes or spinner flasks for 2, 3, 4, or 5 weeks. Chondrocytes were uniformly distributed in the scaffold in the spinner flask cultures, but less so in the Petri dish cultures. Secretion of ECM was found under histology examination. In spinner flask cultures, chondrocytes retained their phenotype for at least 5 weeks, as shown immunohistochemically, and synthesized type II collagen. These results show that gelatin/chondroitin sulfate/hyaluronan tri-copolymer has potential for use as a cartilage tissue engineering scaffold.