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Zhiqian Lu - One of the best experts on this subject based on the ideXlab platform.

  • microstructure property relationship of l lactide trimethylene carbonate glycolide terpolymers as cardiovascular Stent Material
    European Polymer Journal, 2015
    Co-Authors: Lan Liao, Jianting Dong, Gongxi Wang, Suming Li, Zhiqian Lu
    Abstract:

    Abstract A series of terpolymers with various compositions were synthesized by ring-opening polymerization of l -lactide (LLA), trimethylene carbonate (TMC) and glycolide (GA), using stannous (II) octoate as initiator. The microstructure–property relationship of the terpolymers was investigated with the aim of evaluating their potential as cardiovascular Stent Material. The chain microstructure of the PLLA–TMC–GA terpolymers was examined by means of both 1H and 13C nuclear magnetic resonance (NMR) analysis, in comparison with corresponding PLLA–TMC copolymers. The results show that the incorporation of GA moiety instead of TMC moiety leads to shorter average LLA block length. Differential scanning calorimetry (DSC) results show a close relationship between the crystallization behavior and the microstructural sequence. The crystallinity of PLLA-based copolymers mainly depends on the average LLA block length. The mechanical and thermal degradation properties are also affected by both the composition and the chain microstructure, which is of major importance for the development of bioresorbable cardiovascular Stent.

  • Microstructure–property relationship of l-lactide/trimethylene carbonate/glycolide terpolymers as cardiovascular Stent Material
    European Polymer Journal, 2015
    Co-Authors: Lan Liao, Jianting Dong, Gongxi Wang, Suming Li, Zhiqian Lu
    Abstract:

    Abstract A series of terpolymers with various compositions were synthesized by ring-opening polymerization of l -lactide (LLA), trimethylene carbonate (TMC) and glycolide (GA), using stannous (II) octoate as initiator. The microstructure–property relationship of the terpolymers was investigated with the aim of evaluating their potential as cardiovascular Stent Material. The chain microstructure of the PLLA–TMC–GA terpolymers was examined by means of both 1H and 13C nuclear magnetic resonance (NMR) analysis, in comparison with corresponding PLLA–TMC copolymers. The results show that the incorporation of GA moiety instead of TMC moiety leads to shorter average LLA block length. Differential scanning calorimetry (DSC) results show a close relationship between the crystallization behavior and the microstructural sequence. The crystallinity of PLLA-based copolymers mainly depends on the average LLA block length. The mechanical and thermal degradation properties are also affected by both the composition and the chain microstructure, which is of major importance for the development of bioresorbable cardiovascular Stent.

  • totally bioresorbable composites prepared from poly l lactide co trimethylene carbonate copolymers and poly l lactide co glycolide fibers as cardiovascular Stent Material
    Polymer Engineering and Science, 2012
    Co-Authors: Zhiqian Lu, Jian Yang, Suming Li
    Abstract:

    This paper aims to evaluate the potential of totally bioresorbable composites as cardiovascular Stent Material. Copolymers were synthesized by ring-opening polymerization of L-lactide (LLA) and 1,3-trimethylene carbonate (TMC) with LLA-TMC ratios of 3/1, 4/1, and 5/1 and characterized by nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). Wt. 5% of poly(L-lactide)-co-(glycolide) (PLGA) fibers are used to reinforce PTMC-LLA copolymer matrices to prepare totally bioresorbable composites. Heat treatment under vacuum and oxygen plasma treatment are applied to improve the mechanical performance of the composites in terms of eliminating the imperfections inside, enhancing interfacial affinity, surface roughness, and enriching surface oxidative chemical bonds. After plasma treatment, the viscosity and tensile strength of the fibers decrease, but the surface chemical bonds are enriched and surface roughness is increased. The composites with 15-min plasma-treated fibers and 2 h heat treatment exhibit the highest tensile strength of 46 MPa, i.e., very close to that of PLLA (48 MPa), which is usually used as biodegradable Stent Material. Moreover, the tensile modulus of the above composite is 1711 MPa, which is only 34% of PLLA's modulus (4985 MPa). Therefore, novel composites with sufficient tensile strength and better flexibility are obtained as promising cardiovascular Stent Material. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers

  • in vitro degradation of poly l lactide co trimethylene carbonate copolymers and a composite with poly l lactide co glycolide fibers as cardiovascular Stent Material
    Macromolecular Materials and Engineering, 2012
    Co-Authors: Zhiqian Lu, Suming Li
    Abstract:

    TMC/LLA copolymers with several TMC/LLA ratios are synthesized and a composite is obtained by reinforcing with short PLGA fibers. In vitro degradation is studied at 37 °C in pH = 7.4 buffer and compared with a PLLA homopolymer. The degradation of the copolymers appears slower than that of PLLA, showing that TMC units are more resistant to hydrolysis than LLA. Compositional changes indicate a preferential degradation of LLA units as compared to TMC ones. Morphological changes with crystallization of degradation by-products are observed. The composite degrades much faster than the neat copolymer and PLLA because the faster degradation of PLGA fibers speeds up the degradation of the matrix. The composite appears promising for the fabrication of totally bioresorbable Stents.

  • Totally bioresorbable composites prepared from poly(l‐lactide)‐co‐(trimethylene carbonate) copolymers and poly(l‐lactide)‐co‐(glycolide) fibers as cardiovascular Stent Material
    Polymer Engineering and Science, 2011
    Co-Authors: Jian Yang, Zhiqian Lu, Suming Li
    Abstract:

    This paper aims to evaluate the potential of totally bioresorbable composites as cardiovascular Stent Material. Copolymers were synthesized by ring-opening polymerization of L-lactide (LLA) and 1,3-trimethylene carbonate (TMC) with LLA-TMC ratios of 3/1, 4/1, and 5/1 and characterized by nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). Wt. 5% of poly(L-lactide)-co-(glycolide) (PLGA) fibers are used to reinforce PTMC-LLA copolymer matrices to prepare totally bioresorbable composites. Heat treatment under vacuum and oxygen plasma treatment are applied to improve the mechanical performance of the composites in terms of eliminating the imperfections inside, enhancing interfacial affinity, surface roughness, and enriching surface oxidative chemical bonds. After plasma treatment, the viscosity and tensile strength of the fibers decrease, but the surface chemical bonds are enriched and surface roughness is increased. The composites with 15-min plasma-treated fibers and 2 h heat treatment exhibit the highest tensile strength of 46 MPa, i.e., very close to that of PLLA (48 MPa), which is usually used as biodegradable Stent Material. Moreover, the tensile modulus of the above composite is 1711 MPa, which is only 34% of PLLA's modulus (4985 MPa). Therefore, novel composites with sufficient tensile strength and better flexibility are obtained as promising cardiovascular Stent Material. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers

Suming Li - One of the best experts on this subject based on the ideXlab platform.

  • microstructure property relationship of l lactide trimethylene carbonate glycolide terpolymers as cardiovascular Stent Material
    European Polymer Journal, 2015
    Co-Authors: Lan Liao, Jianting Dong, Gongxi Wang, Suming Li, Zhiqian Lu
    Abstract:

    Abstract A series of terpolymers with various compositions were synthesized by ring-opening polymerization of l -lactide (LLA), trimethylene carbonate (TMC) and glycolide (GA), using stannous (II) octoate as initiator. The microstructure–property relationship of the terpolymers was investigated with the aim of evaluating their potential as cardiovascular Stent Material. The chain microstructure of the PLLA–TMC–GA terpolymers was examined by means of both 1H and 13C nuclear magnetic resonance (NMR) analysis, in comparison with corresponding PLLA–TMC copolymers. The results show that the incorporation of GA moiety instead of TMC moiety leads to shorter average LLA block length. Differential scanning calorimetry (DSC) results show a close relationship between the crystallization behavior and the microstructural sequence. The crystallinity of PLLA-based copolymers mainly depends on the average LLA block length. The mechanical and thermal degradation properties are also affected by both the composition and the chain microstructure, which is of major importance for the development of bioresorbable cardiovascular Stent.

  • Microstructure–property relationship of l-lactide/trimethylene carbonate/glycolide terpolymers as cardiovascular Stent Material
    European Polymer Journal, 2015
    Co-Authors: Lan Liao, Jianting Dong, Gongxi Wang, Suming Li, Zhiqian Lu
    Abstract:

    Abstract A series of terpolymers with various compositions were synthesized by ring-opening polymerization of l -lactide (LLA), trimethylene carbonate (TMC) and glycolide (GA), using stannous (II) octoate as initiator. The microstructure–property relationship of the terpolymers was investigated with the aim of evaluating their potential as cardiovascular Stent Material. The chain microstructure of the PLLA–TMC–GA terpolymers was examined by means of both 1H and 13C nuclear magnetic resonance (NMR) analysis, in comparison with corresponding PLLA–TMC copolymers. The results show that the incorporation of GA moiety instead of TMC moiety leads to shorter average LLA block length. Differential scanning calorimetry (DSC) results show a close relationship between the crystallization behavior and the microstructural sequence. The crystallinity of PLLA-based copolymers mainly depends on the average LLA block length. The mechanical and thermal degradation properties are also affected by both the composition and the chain microstructure, which is of major importance for the development of bioresorbable cardiovascular Stent.

  • totally bioresorbable composites prepared from poly l lactide co trimethylene carbonate copolymers and poly l lactide co glycolide fibers as cardiovascular Stent Material
    Polymer Engineering and Science, 2012
    Co-Authors: Zhiqian Lu, Jian Yang, Suming Li
    Abstract:

    This paper aims to evaluate the potential of totally bioresorbable composites as cardiovascular Stent Material. Copolymers were synthesized by ring-opening polymerization of L-lactide (LLA) and 1,3-trimethylene carbonate (TMC) with LLA-TMC ratios of 3/1, 4/1, and 5/1 and characterized by nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). Wt. 5% of poly(L-lactide)-co-(glycolide) (PLGA) fibers are used to reinforce PTMC-LLA copolymer matrices to prepare totally bioresorbable composites. Heat treatment under vacuum and oxygen plasma treatment are applied to improve the mechanical performance of the composites in terms of eliminating the imperfections inside, enhancing interfacial affinity, surface roughness, and enriching surface oxidative chemical bonds. After plasma treatment, the viscosity and tensile strength of the fibers decrease, but the surface chemical bonds are enriched and surface roughness is increased. The composites with 15-min plasma-treated fibers and 2 h heat treatment exhibit the highest tensile strength of 46 MPa, i.e., very close to that of PLLA (48 MPa), which is usually used as biodegradable Stent Material. Moreover, the tensile modulus of the above composite is 1711 MPa, which is only 34% of PLLA's modulus (4985 MPa). Therefore, novel composites with sufficient tensile strength and better flexibility are obtained as promising cardiovascular Stent Material. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers

  • in vitro degradation of poly l lactide co trimethylene carbonate copolymers and a composite with poly l lactide co glycolide fibers as cardiovascular Stent Material
    Macromolecular Materials and Engineering, 2012
    Co-Authors: Zhiqian Lu, Suming Li
    Abstract:

    TMC/LLA copolymers with several TMC/LLA ratios are synthesized and a composite is obtained by reinforcing with short PLGA fibers. In vitro degradation is studied at 37 °C in pH = 7.4 buffer and compared with a PLLA homopolymer. The degradation of the copolymers appears slower than that of PLLA, showing that TMC units are more resistant to hydrolysis than LLA. Compositional changes indicate a preferential degradation of LLA units as compared to TMC ones. Morphological changes with crystallization of degradation by-products are observed. The composite degrades much faster than the neat copolymer and PLLA because the faster degradation of PLGA fibers speeds up the degradation of the matrix. The composite appears promising for the fabrication of totally bioresorbable Stents.

  • Totally bioresorbable composites prepared from poly(l‐lactide)‐co‐(trimethylene carbonate) copolymers and poly(l‐lactide)‐co‐(glycolide) fibers as cardiovascular Stent Material
    Polymer Engineering and Science, 2011
    Co-Authors: Jian Yang, Zhiqian Lu, Suming Li
    Abstract:

    This paper aims to evaluate the potential of totally bioresorbable composites as cardiovascular Stent Material. Copolymers were synthesized by ring-opening polymerization of L-lactide (LLA) and 1,3-trimethylene carbonate (TMC) with LLA-TMC ratios of 3/1, 4/1, and 5/1 and characterized by nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). Wt. 5% of poly(L-lactide)-co-(glycolide) (PLGA) fibers are used to reinforce PTMC-LLA copolymer matrices to prepare totally bioresorbable composites. Heat treatment under vacuum and oxygen plasma treatment are applied to improve the mechanical performance of the composites in terms of eliminating the imperfections inside, enhancing interfacial affinity, surface roughness, and enriching surface oxidative chemical bonds. After plasma treatment, the viscosity and tensile strength of the fibers decrease, but the surface chemical bonds are enriched and surface roughness is increased. The composites with 15-min plasma-treated fibers and 2 h heat treatment exhibit the highest tensile strength of 46 MPa, i.e., very close to that of PLLA (48 MPa), which is usually used as biodegradable Stent Material. Moreover, the tensile modulus of the above composite is 1711 MPa, which is only 34% of PLLA's modulus (4985 MPa). Therefore, novel composites with sufficient tensile strength and better flexibility are obtained as promising cardiovascular Stent Material. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers

Lan Liao - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of bioresorbable polymers as potential Stent Material in vivo degradation behavior and histocompatibility
    Journal of Applied Polymer Science, 2017
    Co-Authors: Lan Liao, Cheng Peng, Zhongyong Fan
    Abstract:

    A PLLA-TMC-GA terpolymer of 90/5/5 molar ratio was synthesized by ring-opening polymerization of l-lactide (LLA), trimethylene carbonate (TMC), and glycolide (GA), using stannous octoate as initiator. In vivo degradation of the obtained terpolymer and a composite made up of the terpolymer matrix reinforced by PLLA-GA fibers was realized by subcutaneous implantation in rats for 9 months, in comparison with PLLA homopolymer and PLLA-TMC copolymer of 95/5 molar ratio. The terpolymer shows ideal degradation profile because it is expected to maintain relatively high radial support for 3 months and lose its mechanical properties in 3 to 6 months inferred from molar mass changes. Increase of crystallinity and LLA content in the terpolymer and composite is observed during degradation. According to the gross observation and H&E staining appearance, all samples present good tissue compatibility. These results suggest that the terpolymer is promising for uses as fully biodegradable vascular scaffold. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44355.

  • microstructure property relationship of l lactide trimethylene carbonate glycolide terpolymers as cardiovascular Stent Material
    European Polymer Journal, 2015
    Co-Authors: Lan Liao, Jianting Dong, Gongxi Wang, Suming Li, Zhiqian Lu
    Abstract:

    Abstract A series of terpolymers with various compositions were synthesized by ring-opening polymerization of l -lactide (LLA), trimethylene carbonate (TMC) and glycolide (GA), using stannous (II) octoate as initiator. The microstructure–property relationship of the terpolymers was investigated with the aim of evaluating their potential as cardiovascular Stent Material. The chain microstructure of the PLLA–TMC–GA terpolymers was examined by means of both 1H and 13C nuclear magnetic resonance (NMR) analysis, in comparison with corresponding PLLA–TMC copolymers. The results show that the incorporation of GA moiety instead of TMC moiety leads to shorter average LLA block length. Differential scanning calorimetry (DSC) results show a close relationship between the crystallization behavior and the microstructural sequence. The crystallinity of PLLA-based copolymers mainly depends on the average LLA block length. The mechanical and thermal degradation properties are also affected by both the composition and the chain microstructure, which is of major importance for the development of bioresorbable cardiovascular Stent.

  • Microstructure–property relationship of l-lactide/trimethylene carbonate/glycolide terpolymers as cardiovascular Stent Material
    European Polymer Journal, 2015
    Co-Authors: Lan Liao, Jianting Dong, Gongxi Wang, Suming Li, Zhiqian Lu
    Abstract:

    Abstract A series of terpolymers with various compositions were synthesized by ring-opening polymerization of l -lactide (LLA), trimethylene carbonate (TMC) and glycolide (GA), using stannous (II) octoate as initiator. The microstructure–property relationship of the terpolymers was investigated with the aim of evaluating their potential as cardiovascular Stent Material. The chain microstructure of the PLLA–TMC–GA terpolymers was examined by means of both 1H and 13C nuclear magnetic resonance (NMR) analysis, in comparison with corresponding PLLA–TMC copolymers. The results show that the incorporation of GA moiety instead of TMC moiety leads to shorter average LLA block length. Differential scanning calorimetry (DSC) results show a close relationship between the crystallization behavior and the microstructural sequence. The crystallinity of PLLA-based copolymers mainly depends on the average LLA block length. The mechanical and thermal degradation properties are also affected by both the composition and the chain microstructure, which is of major importance for the development of bioresorbable cardiovascular Stent.

Nicolaas Lumen - One of the best experts on this subject based on the ideXlab platform.

  • urethroplasty after urethral urolume Stent an international multicenter experience
    Urology, 2018
    Co-Authors: J C Angulo, Sanjay Kulkarni, Joshi Pankaj, Dmitriy Nikolavsky, Pedro Suarez, Javier Belinky, Ramon Virasoro, Jessica Delong, Francisco Martins, Nicolaas Lumen
    Abstract:

    Objective To evaluate the outcomes and factors affecting success of urethroplasty in patients with stricture recurrence after Urolume urethral Stent. Material and Methods This is a retrospective international multicenter study on patients treated with urethral reconstruction after Urolume Stent. Stricture and Stent length, time between urethral Stent insertion and urethroplasty, age, mode of Stent retrieval, type of urethroplasty, complications and baseline, and posturethroplasty voiding parameters were analyzed. Successful outcome was defined as standard voiding, without need of any postoperative adjunctive procedure. Results Sixty-three patients were included. Stent was removed at urethroplasty in 61 patients. Reconstruction technique was excision and primary anastomosis in 14 (22.2%), dorsal onlay buccal mucosa graft (BMG) in 9 (14.3%), ventral onlay BMG in 6 (9.5%), dorsolateral onlay BMG in 9 (14.3%), ventral onlay plus dorsal inlay BMG in 3 (4.8%), augmented anastomosis in 5 (7.9%), pedicled flap urethroplasty in 6 (9.5%), 2-stage procedure in 4 (6.4%), and perineal urethrostomy in 7(11.1%). Success rate was 81% at a mean 59.7 ± 63.4 months. Dilatation or internal urethrotomy was performed in 10 (15.9%) and redo-urethroplasty in 5 (7.9%). Total International Prostate Symptom Score, quality of life, urine maximum flow, and postvoid residual significantly improved (P  Conclusion Urethroplasty in patients with Urolume urethral Stents is a viable option of reconstruction with a high success rate and very acceptable complication rate. Numerous techniques are viable; however, urethral preservation, tine-by-tine Stent extraction, and use of BMG augmentation produced significantly better outcomes.

Kun Zhang - One of the best experts on this subject based on the ideXlab platform.

  • The mechanism of PDA/PEI/5‐Fu coated esophageal Stent Material on inhibiting cancer associated pathological cells
    Journal of biomedical materials research. Part A, 2019
    Co-Authors: Kun Zhang, Yuxin Bai, Fangxia Guan
    Abstract:

    Metal Stent implantation is usually applied to alleviate nonoperative palliative esophageal obstruction for esophageal cancer in the later period. However, in-Stent restenosis after Stent implantation limits the esophageal Stents' performance due to lack of effective suppression of pathological cells from cancer microenvironment. In previous work, we modified the esophageal Stent Material 317L stainless steel (317LSS) surface with a poly-dopamine/poly-ethylenimine/5-fluorouracil layer (PDA/PEI/5-Fu), which had strong anti-tumor and anti-restenosis functions. Nevertheless, the mechanism of PDA/PEI/5-Fu layer against tumor and inflammation remains unclear. In this work, we revealed the mechanism of PDA/PEI/5-Fu suppressing the esophageal cancer related pathological cells (esophageal tumor cells, epithelial cells, and fibroblast) and inflammatory cells (macrophages) via series of experiments. Our data suggested that the PEI inhibited viability and E-cadherin expression of the pathological cells, and blocked the NF-κB signal pathway (reducing levels of p-NF-κB proteins). The loaded 5-Fu inhibited the inflammatory factors (TNF-α and IL-1β) release and promoted the anti-inflammation/anti-tumor factors (IL-10 and IL-4) release from macrophages, and also suppressed pathological cells migration; both the PEI and 5-Fu contributed to the upregulation of Bax and Caspase-3 (pro-tumor-apoptosis factor), as well as the downregulation of Bcl-2 (anti-tumor-apoptosis factor) in esophageal tumor cells. All the results showed that PDA/PEI/5-Fu coating had potential multipath anti-cancer and anti-inflammatory effects in the surface modification of esophageal Stents.

  • Surface Modification of Esophageal Stent Materials by a Drug-Eluting Layer for Better Anti-Restenosis Function
    Coatings, 2018
    Co-Authors: Yuxin Bai, Kun Zhang, Fangxia Guan, Hongtao Liu, Huiwen Luo, Ye Chen
    Abstract:

    It is generally accepted that Stent implantation is the mainstream therapy in clinics for esophageal cancer in the later period. However, the restenosis caused by tumor cells, epithelial cells, and fibroblasts seriously interferes with the Stent medical application and limits its long-term services. To address this conundrum, a series of drug-eluting Stents were invented and verified to be feasible in the early stage after implantation, but the limited drug loading and good cell compatibility of the Stent Materials may lead to more serious restenosis and further endanger the patient’s life. In previous work, we modified the esophageal Stent Material 317L stainless steel (317L SS) surface with a poly-dopamine/poly-ethylenimine layer (PDA/PEI), which had strong anti-tumor functions. In this contribution, we employed a usual drug in clinic, 5-fluorouracil (5-Fu), with series of density onto the PDA/PEI modified 317L SS to investigate the influence of 5-Fu immobilization on the anti-restenosis function. The surface characterization including 5-Fu quantity, atomic force microscopy (AFM). Water contact angle measurement indicated successful preparation of the PDA/PEI/5-Fu layers. The spectrophotometric characterization revealed that the immobilized 5-Fu rapidly released over 24 h. However, the Eca109, Het-1A, and L929 cells culture results suggested that the released 5-Fu made a significant contribution to improving the apoptosis and necrosis of these pathological cells, and the PDA/PEI/5-Fu layers maintain the consiStent anti-restenosis function on their surfaces with the PDA/PEI layer after 24 h. All the results demonstrated the PDA/PEI/5-Fu layers’ excellent ability to suppress esophageal tumor cells, epithelial cells, and fibroblasts, suggesting a potential application on the surface modification of esophageal Stents for better anti-restenosis function.

  • Surface modification of esophageal Stent Materials by a polyethylenimine layer aiming at anti-cancer function.
    Journal of materials science. Materials in medicine, 2017
    Co-Authors: Kun Zhang, Yuxin Bai, Xiaofeng Wang, Fangxia Guan
    Abstract:

    Esophageal cancer is difficult to cure globally and possesses high mortality rate, and it is generally accepted that palliative care such as Stent implantation is the main therapy method for esophageal cancer in later period. However, the restenosis caused by tumor cells and inflammatory cells seriously interferes the Stent clinical application and limits its long-term services. To solve this problem, series of drug delivery Stents were developed and proven rather effective in the early stage of implantation, but more serious restenosis occurred after the drug delivery was over, which endangered the patients’ life. Therefore, endowing the esophageal Stent continuous anti-cancer function become an ideal strategy for inhibiting the restenosis. In this contribution, the functional layer composed of polydopamine (PDA) and Poly-ethylenimine (PEI) with series of molecular weights (MW, 1.8 × 103, 1 × 104, 2.5 × 104 and 7 × 104 Da) were fabricated onto the esophageal Stent Material 317L stainless steel (317L SS) surface. The surface characterization including amine quantitative, atomic force microscopy (AFM) and water contact angle measurement indicated successful preparation of the PDA/PEI layer. The Eca109 cells culture results proved that the PDA/PEI layers significantly improve Eca109 cells apoptosis and necrosis, suggesting excellent anti-cancer function. In addition, we also found that the anti-cancer function of the PDA/PEI layers was positively correlated to the immobilized PEIs’ MW. All the results demonstrated the potential application of the PDA/PEI layers on the surface modification of esophageal Stent for continuous anti-cancer function. It is generally accepted that the restenosis caused by tumor cells seriously interferes the esophageal Stent clinical application. Thus, endowing the esophageal Stent continuous anti-cancer function is the ideal strategy for inhibiting the restenosis. In this work, we fabricated functional layers composed of polydopamine (PDA) and Poly-ethylenimine (PEI) with series of molecular weights (MW, 1.8 × 103, 1 × 104, 2.5 × 104 and 7 × 104 Da) onto the esophageal Stent Material 317L stainless steel (317L SS) surface to inhibit the tumor cells growth, and this function was related to the PEIs’ molecular weights. The functional PDA/PEI layers were expected potentially applied for surface modification of esophageal Stent Materials.

  • A novel coating of type IV collagen and hyaluronic acid on Stent Material-titanium for promoting smooth muscle cell contractile phenotype
    Materials science & engineering. C Materials for biological applications, 2014
    Co-Authors: Kun Zhang, Huiqing Chen, Tao Liu, Ping Yang, Yuancong Zhao, Nan Huang
    Abstract:

    The method of Stent implantation is currently considered an effective means of treating atherosclerosis. However, implanting of cardiovascular Stent often leads to intimal breakage and hyperplasia. The phenomenon that vascular smooth muscle cells (SMCs) transform from contractile to synthetic phenotype becomes a serious obstacle to intimal recovery. To improve how SMCs transform from a synthetic to contractile phenotype, a technique of coimmobilization was used to form type IV collagen (CoIV) and hyaluronic acid (HA) coating on the widely used Stent Material, titanium (Ti). In this work, several bio-functional coatings made of CoIV/HA mixtures in different ratios were fabricated on the Ti surface. The quantitative characterization of CoIV showed that introducing HA could enhance the amount of the immobilized CoIV on the alkali activated Ti (TiOH) surface. The immunofluorescence staining results of myosin heavy chain (MHC) and DAPI showed that the coating of CoIV/HA in ratios of 200 μg/ml (M200) and 500 μg/ml (M500) also could promote SMCs expressing more contractile phenotype compared with TiOH/CoIV control samples, while the AO/PI staining results indicated that SMCs on the M200 and M500 samples showed less apoptosis ratio. Thus, we hope that this study can provide more helpful exploration and application for promoting the SMC contractile phenotype on the cardiovascular Stents.