Extended Abstract In this study a novel kind of reinforcing polymethylmethacrylate (PMMA) aas well as improving the electrical properties of polyetherimide (PEI) with a 2 generation of layered silicates is shown. Layered silicates are used as nanofillers in polymers due to their ability to increase the mechanical strength as well as to improve flame retardancy [1] and barrier properties [2], respectively. The first studies about polymeric nanocomposites with layered silicates were published in the mid eighties of the last century and lead to the development of a nylon-6-montmorillonite nanocomposite which has been the first layered silicate nanocomposite to be commercialized [3]. Since these first studies about polymer/clay nanocomposites [4], a rapid development has brought further improvement of the overall properties of these materials. However, the potential of commercially available natural layered silicates seems to have reached its limitations due to small lateral dimensions and a high heterogeneity of surface charge. Processing via melt compounding results mostly in incomplete delamination of the tactoids, which further reduces the maximal possible aspect ratio and therefore the desired properties. Also the incorporation of commercially available natural organo-clay in PMMA by melt-compounding leads to an increase of the stiffness, but an unsatisfactory dispersion quality of the nanoclay in the PMMA matrix. This leads to an decrease in toughness. Therefore we developed a new kind of synthetic layered silicate and used them in an innovative transfer batch moulding process to create a PMMA-nanocomposite. With these synthetic layered silicates which have aspect ratios of up to 600, it was possible to significantly increase the young’s modulus of about 55% and the fracture toughness of about 70 %, without any decrease in tensile strength. Furthermore analysis of the corresponding fracture surfaces by scanning electron microscopy show in case of the novel filler additional energy dissipating mechanisms like crack deflection, crack bridging as well as debonding effects with platelets pull-out leading to enhanced fracture toughness. In addition to the improvement of the mechanical behavior, the layered silicates possess the ability to decrease the coefficient of thermal expansion (CTE) of the matrix material [5]. Therefore layered silicates provide the possibility of utilizing thermoplastic materials for applications which require a lower CTE. In electric devices e.g. substrate material has to have a CTE in the range of the copper foil (around 17 ppm/K) to avoid thermal stresses between materials. Therefore current studies are evaluating the effect of layered silicates on thermal and electrical properties of PEI.
{"title":"2nd Generation Layered Silicates Nanocomposites with improved Mechanical and Electrical Properties","authors":"V. Altstädt, J. Breu","doi":"10.11159/ICNNFC16.110","DOIUrl":"https://doi.org/10.11159/ICNNFC16.110","url":null,"abstract":"Extended Abstract In this study a novel kind of reinforcing polymethylmethacrylate (PMMA) aas well as improving the electrical properties of polyetherimide (PEI) with a 2 generation of layered silicates is shown. Layered silicates are used as nanofillers in polymers due to their ability to increase the mechanical strength as well as to improve flame retardancy [1] and barrier properties [2], respectively. The first studies about polymeric nanocomposites with layered silicates were published in the mid eighties of the last century and lead to the development of a nylon-6-montmorillonite nanocomposite which has been the first layered silicate nanocomposite to be commercialized [3]. Since these first studies about polymer/clay nanocomposites [4], a rapid development has brought further improvement of the overall properties of these materials. However, the potential of commercially available natural layered silicates seems to have reached its limitations due to small lateral dimensions and a high heterogeneity of surface charge. Processing via melt compounding results mostly in incomplete delamination of the tactoids, which further reduces the maximal possible aspect ratio and therefore the desired properties. Also the incorporation of commercially available natural organo-clay in PMMA by melt-compounding leads to an increase of the stiffness, but an unsatisfactory dispersion quality of the nanoclay in the PMMA matrix. This leads to an decrease in toughness. Therefore we developed a new kind of synthetic layered silicate and used them in an innovative transfer batch moulding process to create a PMMA-nanocomposite. With these synthetic layered silicates which have aspect ratios of up to 600, it was possible to significantly increase the young’s modulus of about 55% and the fracture toughness of about 70 %, without any decrease in tensile strength. Furthermore analysis of the corresponding fracture surfaces by scanning electron microscopy show in case of the novel filler additional energy dissipating mechanisms like crack deflection, crack bridging as well as debonding effects with platelets pull-out leading to enhanced fracture toughness. In addition to the improvement of the mechanical behavior, the layered silicates possess the ability to decrease the coefficient of thermal expansion (CTE) of the matrix material [5]. Therefore layered silicates provide the possibility of utilizing thermoplastic materials for applications which require a lower CTE. In electric devices e.g. substrate material has to have a CTE in the range of the copper foil (around 17 ppm/K) to avoid thermal stresses between materials. Therefore current studies are evaluating the effect of layered silicates on thermal and electrical properties of PEI.","PeriodicalId":31009,"journal":{"name":"RAN","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85643413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Nickel Oxide Nanoparticles Synthesized Under Microwave Irradiation","authors":"Armando Rodríguez, B. Kharisov, A. Vázquez","doi":"10.11159/icnnfc16.115","DOIUrl":"https://doi.org/10.11159/icnnfc16.115","url":null,"abstract":"","PeriodicalId":31009,"journal":{"name":"RAN","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80266588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Extended Abstract Graphene, a single layer of graphite, has attracted much attention due to its physical properties and two-dimensional structure. It has been used in many important industrial applications, including batteries, electronic devices and sensors. The cleanliness of graphene surfaces is important for successful uses of graphene in these applications. Surfaces of highly oriented pyrolytic graphite (HOPG), which can be regarded as the surfaces of defect-free graphene and surfaces of graphene were characterized by two very powerful surface analysis techniques X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) [1-4]. XPS results indicated that the impurities on the surfaces of graphene and HOPG can be removed by annealing samples of graphene and HOPG in vacuum at 400 o C [5]. In addition, ToF-SIMS results showed that even a small amount of poly(methyl methacrylate) (PMMA) impurity on the graphene surface can be removed by annealing the sample in vacuum at 500 o C. In the C1s spectrum of clean HOPG, an asymmetric sp 2 carbon peak and a π-π* shake-up peak were present, indicating the absence of defects. An additional sp 3
{"title":"Characterization of HOPG, Sputtered HPOG and Graphene by ToF-SIMS and XPS","authors":"C. Chan, Wenjing Xie, L. Weng, K. Ng, C. Chan","doi":"10.11159/ICNEI16.103","DOIUrl":"https://doi.org/10.11159/ICNEI16.103","url":null,"abstract":"Extended Abstract Graphene, a single layer of graphite, has attracted much attention due to its physical properties and two-dimensional structure. It has been used in many important industrial applications, including batteries, electronic devices and sensors. The cleanliness of graphene surfaces is important for successful uses of graphene in these applications. Surfaces of highly oriented pyrolytic graphite (HOPG), which can be regarded as the surfaces of defect-free graphene and surfaces of graphene were characterized by two very powerful surface analysis techniques X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) [1-4]. XPS results indicated that the impurities on the surfaces of graphene and HOPG can be removed by annealing samples of graphene and HOPG in vacuum at 400 o C [5]. In addition, ToF-SIMS results showed that even a small amount of poly(methyl methacrylate) (PMMA) impurity on the graphene surface can be removed by annealing the sample in vacuum at 500 o C. In the C1s spectrum of clean HOPG, an asymmetric sp 2 carbon peak and a π-π* shake-up peak were present, indicating the absence of defects. An additional sp 3","PeriodicalId":31009,"journal":{"name":"RAN","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90374243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bacterial infections represent an increasing worldwide threat. The number of untreatable diseases decreased after the 1950s due to the introduction of antimicrobial agents. However, since the 1980s, morbidity has risen again, and mortality due to respiratory infections, AIDS and tuberculosis now represents about 85% of world mortality from infections [1,2]. The increase in the number of new infections is caused by general immunosuppression (primarily by tumour treatment, administration of immunosuppressive agents, wide-spectrum antibiotics and corticoids), a significant increase in the number of diabetic or HIV-positive patients and development of resistance to commonly used drugs. The resistance of common pathogens to first-choice drugs increased by up to 100% during the last decade. Moreover, the resistance of some strains to secondor third-choice drugs can be found. Development of cross-resistant or multidrug-resistant strains (Mycobacterium spp., Staphylococcus, Enterococcus, Salmonella, Pseudomonas, Klebsiella, Candida spp., Aspergillus spp. and Cryptococcus spp.) is a great problem [3,4]. Selection of resistant microorganisms is especially caused by irrational and unavailing application of antimicrobial agents in human, veterinary medicine and in agriculture [1,5–8]. Bacterial resistance may complicate the treatment of infections regardless of how mild these infections were at the early stage [9]. Infections caused by these MDR bacterial strains have been responsible for the increase in additional healthcare costs and productivity losses [3,4,7,10]. Although it is not difficult to discover microbicidal agents, it is increasingly complicated to design new classes of antimicrobial compounds suitable for following rational development [11], therefore R&D of new antimicrobials imply risks, and thus many pharmaceutical originators have continued in development of me-too drugs. Increasing bacterial resistance refers to the urgency to design new effective antibacterial drugs [12–14]. Application of nanotechnology represents an excellent alternative for improvement of existing antimicrobial drugs. Nanomaterials are an alternative approach to treatment and mitigation of infections caused by resistant strains. Microbial cells are unlikely to develop resistance to nanomaterials, because, in contrast to conventional antibiotics, they exert toxicity through various mechanisms [15]. Using nanosystems/nanoformulations, enhanced bioavailability of active substance can be ensured, and the route of administration can be modified. Specific nanoformulations also provide a controlled released system or targeted biodistribution. Due to these facts, smaller amount of substance can be used, i.e. dose-dependent toxicity and various side effects decrease. An increase in the efficacy of individual agents can be ensured by fixed-dose drug combinations or antimicrobially active matrices – polymers physically destroying cell membranes of the organism and rendering them
{"title":"Nanoformulations of Antimicrobial Chemotherapeutics","authors":"J. Jampílek","doi":"10.11159/NDDTE16.2","DOIUrl":"https://doi.org/10.11159/NDDTE16.2","url":null,"abstract":"Bacterial infections represent an increasing worldwide threat. The number of untreatable diseases decreased after the 1950s due to the introduction of antimicrobial agents. However, since the 1980s, morbidity has risen again, and mortality due to respiratory infections, AIDS and tuberculosis now represents about 85% of world mortality from infections [1,2]. The increase in the number of new infections is caused by general immunosuppression (primarily by tumour treatment, administration of immunosuppressive agents, wide-spectrum antibiotics and corticoids), a significant increase in the number of diabetic or HIV-positive patients and development of resistance to commonly used drugs. The resistance of common pathogens to first-choice drugs increased by up to 100% during the last decade. Moreover, the resistance of some strains to secondor third-choice drugs can be found. Development of cross-resistant or multidrug-resistant strains (Mycobacterium spp., Staphylococcus, Enterococcus, Salmonella, Pseudomonas, Klebsiella, Candida spp., Aspergillus spp. and Cryptococcus spp.) is a great problem [3,4]. Selection of resistant microorganisms is especially caused by irrational and unavailing application of antimicrobial agents in human, veterinary medicine and in agriculture [1,5–8]. Bacterial resistance may complicate the treatment of infections regardless of how mild these infections were at the early stage [9]. Infections caused by these MDR bacterial strains have been responsible for the increase in additional healthcare costs and productivity losses [3,4,7,10]. Although it is not difficult to discover microbicidal agents, it is increasingly complicated to design new classes of antimicrobial compounds suitable for following rational development [11], therefore R&D of new antimicrobials imply risks, and thus many pharmaceutical originators have continued in development of me-too drugs. Increasing bacterial resistance refers to the urgency to design new effective antibacterial drugs [12–14]. Application of nanotechnology represents an excellent alternative for improvement of existing antimicrobial drugs. Nanomaterials are an alternative approach to treatment and mitigation of infections caused by resistant strains. Microbial cells are unlikely to develop resistance to nanomaterials, because, in contrast to conventional antibiotics, they exert toxicity through various mechanisms [15]. Using nanosystems/nanoformulations, enhanced bioavailability of active substance can be ensured, and the route of administration can be modified. Specific nanoformulations also provide a controlled released system or targeted biodistribution. Due to these facts, smaller amount of substance can be used, i.e. dose-dependent toxicity and various side effects decrease. An increase in the efficacy of individual agents can be ensured by fixed-dose drug combinations or antimicrobially active matrices – polymers physically destroying cell membranes of the organism and rendering them ","PeriodicalId":31009,"journal":{"name":"RAN","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88862898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Extended Abstract Silver nanowire-based transparent electrode was demonstrated as an anode for large-area organic light-emitting diodes (OLEDs). The electrode transparency depends on the density of the silver nanowire network that determines the sheet resistance of the electrode. The trade-off between the transparency and electrical resistance can be circumvented by utilizing an auxiliary silver-grid electrode for developing a large-area flexible electrode with high transparency and low resistance. In order to apply the silver nanowire-based transparent electrode to the anode for OLEDs, the surface roughness should be minimized to reduce the leakage current through the nanometer-thin devices. A roll-to-roll fabrication process was utilized to fabricate a large-area and planarized flexible transparent electrode with silver nanowire and silver auxiliary grid on a polyethylene terephthalate (PET) substrate. The sheet resistance and optical transmittance of the transparent electrode were 5 ohm/square and 90%, respectively. The planarized electrode surface was flat enough to fabricate OLED devices directly on the surface. Due to the scattering effect of the silver nanowire networks, the device efficiency was superior to that fabricated on the conventional ITO glass substrates. Patterned large-area OLED devices were fabricated on the silver nanowire-based transparent anode using a roll-to-roll deposition process. The OLED devices is 10 cm wide and the length is not limited on a 15 cm wide PET roll. The OLED devices were protected with top and bottom moisture barrier layers deposited by an atomic layer deposition method from moisture and oxygen.[1,2] A few technical subjects on the roll-to-roll fabrication processes, emission uniformity, electrode uniformity and surface roughness will be discussed along with a few applications of the large-area flexible OLEDs in the presentation.
{"title":"Silver Nanowire-based Transparent Electrode as Flexible Anode for Large-Area Organic Light-Emitting Diodes","authors":"Minha Kim, Eunji Jung, S. Cho","doi":"10.11159/ICNNFC16.118","DOIUrl":"https://doi.org/10.11159/ICNNFC16.118","url":null,"abstract":"Extended Abstract Silver nanowire-based transparent electrode was demonstrated as an anode for large-area organic light-emitting diodes (OLEDs). The electrode transparency depends on the density of the silver nanowire network that determines the sheet resistance of the electrode. The trade-off between the transparency and electrical resistance can be circumvented by utilizing an auxiliary silver-grid electrode for developing a large-area flexible electrode with high transparency and low resistance. In order to apply the silver nanowire-based transparent electrode to the anode for OLEDs, the surface roughness should be minimized to reduce the leakage current through the nanometer-thin devices. A roll-to-roll fabrication process was utilized to fabricate a large-area and planarized flexible transparent electrode with silver nanowire and silver auxiliary grid on a polyethylene terephthalate (PET) substrate. The sheet resistance and optical transmittance of the transparent electrode were 5 ohm/square and 90%, respectively. The planarized electrode surface was flat enough to fabricate OLED devices directly on the surface. Due to the scattering effect of the silver nanowire networks, the device efficiency was superior to that fabricated on the conventional ITO glass substrates. Patterned large-area OLED devices were fabricated on the silver nanowire-based transparent anode using a roll-to-roll deposition process. The OLED devices is 10 cm wide and the length is not limited on a 15 cm wide PET roll. The OLED devices were protected with top and bottom moisture barrier layers deposited by an atomic layer deposition method from moisture and oxygen.[1,2] A few technical subjects on the roll-to-roll fabrication processes, emission uniformity, electrode uniformity and surface roughness will be discussed along with a few applications of the large-area flexible OLEDs in the presentation.","PeriodicalId":31009,"journal":{"name":"RAN","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86667263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jung Dong Kim, Jungeun Bae, Hong Kee Kim, Do Hyeon Jeong
Extended Abstract The microneedle mediated drug delivery system has been developed to provide painless self-administration of highpotency drug with patient friendly manner [1]. Especially, dissolving microneedles, which deliver the target drugs as the drug-loaded microneedle dissolves into the skin, have been spotlighted recently [2]. Conventional dissolving microneedles have been mostly produced by a stepwise casting method in three-dimensional (3D) molds. In this casting method, filling the mold cavity without drug loss is a challenge. The curing step, which is critical to provide strength to the microneedleshaped polymer and for solidification, requires conditions that are harsh to biological drugs, such as heat or ultraviolet (UV) light [3]. Also, this time consuming step causes the activity loss of biological drugs. Recently, drawing lithography, which can create three-dimensional microstructures from two-dimensional (2D) thermosetting materials, was suggested to fabricate dissolving microneedles [4]. Although drawing lithography has the advantage of fabricating dissolving microneedles without using a mold, it still requires high temperatures to draw and harden the thermosetting materials and limits the use of heatsensitive biological drugs. This study suggests the novel dissolving microneedle fabrication technique, droplet-born air blowing (DAB), in which the polymer droplet is shaped to the microneedle via air blowing [5]. Because the air blowing is directly applied to the polymer droplet to solidify and thus to form the microneedle shape, DAB provides gentle fabrication conditions without heat or UV irradiation. Also, the fabrication of dissolving microneedle from each droplet makes it possible to load the drug in the microneedle without drug loss and provides precise drug dose by controlling the droplet volume and the concentration of drug in the droplet. Additionally, the dissolving microneedle can be fabricated within 10 min via DAB, and this provides additional benefits in regard to fabrication cost and maintaining the activity of drugs. Here, we fabricated epidermal growth factor (EGF) and insulin loaded dissolving microneedles via DAB. The skin penetration property of EGF loaded microneedles was showed by optical coherence tomography (OCT). And the time versus blood glucose level in mice after subcutaneous injection and microneedle patch administration of insulin are shown no significant difference. The blood glucose level was dramatically reduced after a 60 min insulin administration (n=6, p<0.0001) and recovered after 120 min in both groups. Overall, the DAB could provide a solution to the problems of conventional dissolving microneedle fabrication technology, suggesting the potential application of biological drug delivery system.
微针介导给药系统的发展是为了提供高效能药物的无痛自我给药和患者友好的方式[1]。尤其是溶解型微针，随着载药微针溶解到皮肤中，将靶药物输送到皮肤中，最近引起了人们的关注[2]。传统的溶解微针大多是在三维(3D)模具中采用分步铸造方法生产的。在这种铸造方法中，在没有药物损失的情况下填充模腔是一个挑战。固化步骤是为微针状聚合物提供强度和固化的关键步骤，它需要对生物药物苛刻的条件，如热或紫外线(UV)光[3]。此外，这一耗时的步骤会导致生物药物的活性丧失。最近，利用二维(2D)热固性材料制作三维微结构的拉伸光刻技术被建议用于制造可溶解的微针[4]。尽管拉伸光刻技术具有无需模具就能制造可溶解微针的优点，但它仍然需要高温来拉伸和硬化热固性材料，限制了热敏性生物药物的使用。本研究提出了一种新型的溶解微针制造技术——滴生空气吹制(drop -born air blowing, DAB)，即聚合物液滴通过空气吹制形成微针[5]。由于吹风直接作用于聚合物液滴固化，从而形成微针形状，DAB提供了温和的制造条件，无需加热或紫外线照射。此外，从每个液滴中制备溶解微针，使得可以在不损失药物的情况下将药物装入微针中，并通过控制液滴体积和液滴中的药物浓度提供精确的药物剂量。此外，可溶解的微针可以通过DAB在10分钟内制造，这在制造成本和保持药物活性方面提供了额外的好处。本研究通过DAB制备了负载表皮生长因子(EGF)和胰岛素的溶解微针。光学相干断层扫描(OCT)显示了负载EGF的微针的皮肤穿透特性。皮下注射胰岛素和微针贴片给药后小鼠的时间与血糖水平无显著差异。胰岛素给药60 min后血糖水平显著降低(n=6, p<0.0001)， 120 min后血糖水平恢复正常。综上所述，DAB可解决传统溶解微针制造技术存在的问题，在生物给药系统中具有潜在的应用前景。
{"title":"Droplet-born Air Blowing(DAB) Technology for the Industrialization of Dissolving Microneedle","authors":"Jung Dong Kim, Jungeun Bae, Hong Kee Kim, Do Hyeon Jeong","doi":"10.11159/NDDTE16.122","DOIUrl":"https://doi.org/10.11159/NDDTE16.122","url":null,"abstract":"Extended Abstract The microneedle mediated drug delivery system has been developed to provide painless self-administration of highpotency drug with patient friendly manner [1]. Especially, dissolving microneedles, which deliver the target drugs as the drug-loaded microneedle dissolves into the skin, have been spotlighted recently [2]. Conventional dissolving microneedles have been mostly produced by a stepwise casting method in three-dimensional (3D) molds. In this casting method, filling the mold cavity without drug loss is a challenge. The curing step, which is critical to provide strength to the microneedleshaped polymer and for solidification, requires conditions that are harsh to biological drugs, such as heat or ultraviolet (UV) light [3]. Also, this time consuming step causes the activity loss of biological drugs. Recently, drawing lithography, which can create three-dimensional microstructures from two-dimensional (2D) thermosetting materials, was suggested to fabricate dissolving microneedles [4]. Although drawing lithography has the advantage of fabricating dissolving microneedles without using a mold, it still requires high temperatures to draw and harden the thermosetting materials and limits the use of heatsensitive biological drugs. This study suggests the novel dissolving microneedle fabrication technique, droplet-born air blowing (DAB), in which the polymer droplet is shaped to the microneedle via air blowing [5]. Because the air blowing is directly applied to the polymer droplet to solidify and thus to form the microneedle shape, DAB provides gentle fabrication conditions without heat or UV irradiation. Also, the fabrication of dissolving microneedle from each droplet makes it possible to load the drug in the microneedle without drug loss and provides precise drug dose by controlling the droplet volume and the concentration of drug in the droplet. Additionally, the dissolving microneedle can be fabricated within 10 min via DAB, and this provides additional benefits in regard to fabrication cost and maintaining the activity of drugs. Here, we fabricated epidermal growth factor (EGF) and insulin loaded dissolving microneedles via DAB. The skin penetration property of EGF loaded microneedles was showed by optical coherence tomography (OCT). And the time versus blood glucose level in mice after subcutaneous injection and microneedle patch administration of insulin are shown no significant difference. The blood glucose level was dramatically reduced after a 60 min insulin administration (n=6, p<0.0001) and recovered after 120 min in both groups. Overall, the DAB could provide a solution to the problems of conventional dissolving microneedle fabrication technology, suggesting the potential application of biological drug delivery system.","PeriodicalId":31009,"journal":{"name":"RAN","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76613370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zdenek Sofer, D. Sedmidubský, J. Luxa, O. Jankovský, D. Bouša, K. Klímová, M. Pumera
{"title":"Graphene and Its Derivates, Applications and Environmental Issues","authors":"Zdenek Sofer, D. Sedmidubský, J. Luxa, O. Jankovský, D. Bouša, K. Klímová, M. Pumera","doi":"10.11159/ICNEI16.1","DOIUrl":"https://doi.org/10.11159/ICNEI16.1","url":null,"abstract":"","PeriodicalId":31009,"journal":{"name":"RAN","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78713739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The aim of this study was to investigate the effect of Fe3O4 (magnetite) nanoparticles on the properties of magnetitecontaining chitosan-poly(N,N-diethylacrylamide) semi-interpenetrated network (CS-DE-M semi-IPN) films. For that purpose, nanosized (≤ 50 nm) magnetite-containing CS-DE-M semi-IPN films were prepared at four different initial N,N-diethylacrylamide concentrations. For the comparison purpose, CS-DE semi-IPN films without magnetite were also prepared under the same conditions with those of CS-DE-M films. The structural and thermal characterization of CS-DE-M and CS-DE films were performed by FTIR and DSC methods, respectively. The variation of swelling behavior of semi-IPN films with temperature was investigated in distilled water at four different temperatures between 10 – 40C with step of 10C. The equilibrium swelling values of CS-DE films were found to be three times higher than those of CS-DE-M films at all investigated temperatures. The swelling values of both polymer films decreased with the increase in DE concentration in CS solution. In addition, the lowest swelling was observed at 10C, and it increased with the increase in temperature in contrary to the expected results from a thermo-responsive polymer such as poly(N,N-diethylacrylamide). Normally, the swelling of a thermoresponsive polymer decreases with temperature, in the case of CS-DE and CS-DE-M films, however, the maximum poly(N,N-diethylacrylamide) content is between 27% and 57%, and it is too low to display a response to temperature as shrinking.
{"title":"The Synthesis and Characterization of Magnetic Chitosan-poly(N,Ndiethylacrylamide) Semi-IPN Films","authors":"Burcu Aydogdu, A. Alipour, G. Gürdağ","doi":"10.11159/ICNNFC16.123","DOIUrl":"https://doi.org/10.11159/ICNNFC16.123","url":null,"abstract":"The aim of this study was to investigate the effect of Fe3O4 (magnetite) nanoparticles on the properties of magnetitecontaining chitosan-poly(N,N-diethylacrylamide) semi-interpenetrated network (CS-DE-M semi-IPN) films. For that purpose, nanosized (≤ 50 nm) magnetite-containing CS-DE-M semi-IPN films were prepared at four different initial N,N-diethylacrylamide concentrations. For the comparison purpose, CS-DE semi-IPN films without magnetite were also prepared under the same conditions with those of CS-DE-M films. The structural and thermal characterization of CS-DE-M and CS-DE films were performed by FTIR and DSC methods, respectively. The variation of swelling behavior of semi-IPN films with temperature was investigated in distilled water at four different temperatures between 10 – 40C with step of 10C. The equilibrium swelling values of CS-DE films were found to be three times higher than those of CS-DE-M films at all investigated temperatures. The swelling values of both polymer films decreased with the increase in DE concentration in CS solution. In addition, the lowest swelling was observed at 10C, and it increased with the increase in temperature in contrary to the expected results from a thermo-responsive polymer such as poly(N,N-diethylacrylamide). Normally, the swelling of a thermoresponsive polymer decreases with temperature, in the case of CS-DE and CS-DE-M films, however, the maximum poly(N,N-diethylacrylamide) content is between 27% and 57%, and it is too low to display a response to temperature as shrinking.","PeriodicalId":31009,"journal":{"name":"RAN","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90225850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Extended Abstract Selenium nanoparticles (SeNPs), which range in size from 50 to 300 nm, show broad applications such as antioxidant, immunoprotective, anti-tumor, antimicrobial and antobiofilm activities [1]. They also can be exploited in bioremediation, production of quantum dots and biosensors. SeNPs can be synthesized chemically (ChSeNPs) or biologically (BioSeNPs). BioSeNPs can be obtained by various microorganisms, plant extracts or enzymatic preparations. Biosynthesis offers advantages over chemical synthesis such as minor costs, absence of toxic by products and energy saving (i.e. carried out under mild environmental conditions). BioSeNPs also present an outer layer, mainly consisting of a proteinaceous material, that seems to greatly influence the reactivity of SeNPs in terms of antimicrobial and antibiofilm effects. It has been proved that antimicrobial activity of BioSeNPs is significantly more than ChSeNPs. To better understand possible mechanisms of this antimicrobial/antibiofilm efficacy of BioSeNPs, the nature of their outer layer should be characterized in details. In fact, the description of such surface-associated proteins and specificity of their binding to metal nanoparticles might allow to formulate new hypotheses on the biosynthetic route of SeNPs. Likely, nanoparticle-associated proteins are involved in the synthesis and maturation of SeNPs themselves. This study focuses on the proteomic characterization of BioSeNPs external layer. For biogenic production of SeNPs, we used Bacillus mycoides SeITE01, an environmental strain isolated from the selenium-hyperaccumulator legume Astragalus bisulcatus rizosphere, capable of tolerating up to 25mM selenite [2]. The first step of the research was the characterization of protein associated to BioSeNPs through SDS-PAGE and mass spectrometry after 24 hours growth in the presence of selenite. Moreover, we studied the specificity of the protein-NP bond. Since ChSeNPs can also bind proteins when exposed to a cell free protein extract, a comparison between proteins associated to BioSeNPs and exposed ChSeNPs is currently ongoing. We identified BioSeNPs-associated proteins for B. mycoides, which belong to primary and secondary metabolism, especially protein and amino acid metabolisms. As expected, proteins capable of reductase activity were found which are possibly involved in selenite reduction to zero-valent SeNPs: pyridine-nucleotide disulphide oxidoreductase, enoyl-ACP reductase (fatty acid biosynthesis) and FMN-dependent NADH azoreductase. Some membrane transporter and proteins involved in cell wall metabolism were also found, such as: penicillin-binding protein and lysozyme (peptidoglycan synthesis and degradation pathways, respectively) and ABC transporters. Several proteins involved in polypeptide synthesis and aminoacid metabolism were identified including: elongation factors Tu and G, ribosomal proteins, peptidases and a protease; glutamate and alanine dehydrogenases. Some of these
{"title":"Proteomic Study of the Outer Layer of Biogenic Selenium Nanoparticles","authors":"A. Bulgarini, D. Cecconi, S. Lampis, G. Vallini","doi":"10.11159/ICNNFC16.114","DOIUrl":"https://doi.org/10.11159/ICNNFC16.114","url":null,"abstract":"Extended Abstract Selenium nanoparticles (SeNPs), which range in size from 50 to 300 nm, show broad applications such as antioxidant, immunoprotective, anti-tumor, antimicrobial and antobiofilm activities [1]. They also can be exploited in bioremediation, production of quantum dots and biosensors. SeNPs can be synthesized chemically (ChSeNPs) or biologically (BioSeNPs). BioSeNPs can be obtained by various microorganisms, plant extracts or enzymatic preparations. Biosynthesis offers advantages over chemical synthesis such as minor costs, absence of toxic by products and energy saving (i.e. carried out under mild environmental conditions). BioSeNPs also present an outer layer, mainly consisting of a proteinaceous material, that seems to greatly influence the reactivity of SeNPs in terms of antimicrobial and antibiofilm effects. It has been proved that antimicrobial activity of BioSeNPs is significantly more than ChSeNPs. To better understand possible mechanisms of this antimicrobial/antibiofilm efficacy of BioSeNPs, the nature of their outer layer should be characterized in details. In fact, the description of such surface-associated proteins and specificity of their binding to metal nanoparticles might allow to formulate new hypotheses on the biosynthetic route of SeNPs. Likely, nanoparticle-associated proteins are involved in the synthesis and maturation of SeNPs themselves. This study focuses on the proteomic characterization of BioSeNPs external layer. For biogenic production of SeNPs, we used Bacillus mycoides SeITE01, an environmental strain isolated from the selenium-hyperaccumulator legume Astragalus bisulcatus rizosphere, capable of tolerating up to 25mM selenite [2]. The first step of the research was the characterization of protein associated to BioSeNPs through SDS-PAGE and mass spectrometry after 24 hours growth in the presence of selenite. Moreover, we studied the specificity of the protein-NP bond. Since ChSeNPs can also bind proteins when exposed to a cell free protein extract, a comparison between proteins associated to BioSeNPs and exposed ChSeNPs is currently ongoing. We identified BioSeNPs-associated proteins for B. mycoides, which belong to primary and secondary metabolism, especially protein and amino acid metabolisms. As expected, proteins capable of reductase activity were found which are possibly involved in selenite reduction to zero-valent SeNPs: pyridine-nucleotide disulphide oxidoreductase, enoyl-ACP reductase (fatty acid biosynthesis) and FMN-dependent NADH azoreductase. Some membrane transporter and proteins involved in cell wall metabolism were also found, such as: penicillin-binding protein and lysozyme (peptidoglycan synthesis and degradation pathways, respectively) and ABC transporters. Several proteins involved in polypeptide synthesis and aminoacid metabolism were identified including: elongation factors Tu and G, ribosomal proteins, peptidases and a protease; glutamate and alanine dehydrogenases. Some of these ","PeriodicalId":31009,"journal":{"name":"RAN","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83379161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Extended Abstract Polysaccharide is one of widely utilized materials in biomedical areas due to its excellent biocompatibility. However, most polysaccharide-based hydrogels are typically prepared in the presence of excipient chemical reagents that may cause toxicity. In this presentation, we report how hyaluronate hydrogels can be prepared without toxic chemical cross-linking agents. Hyaluronate is composed of β-1,4-D-glucuronic acid-β-1,3-N-acetyl-D-glucosamine residues, and is abundant in synovial fluid and extracellular matrix. We introduced alginate to the hyaluronate backbone, allowing gel formation in the presence of calcium ions [1]. The mechanical properties of hydrogels were varied depending on type and concentration of polysaccharide. Tissue regeneration using these hydrogels were carried out by subcutaneous injection of primary chondrocyte/hydrogel constructs into a mouse model. In addition, a control of stem cell phenotype using hydrogels has been extensively investigated, and a use of cellinstructive polymers is critical to regulate the proliferation and differentiation of mesenchymal stem cells (MSCs) [2]. In this presentation, we report a biomimetic system to culture MSCs by providing stem cell niche using cell-instructive alginate microspheres. Chondrogenic differentiation of MSCs is typically influenced by aggregate formation [3] and cadherin is a key factor in mediating cell-cell interactions during stem cell condensation and chondrogenesis. Alginate microspheres, prepared by the water-in-oil emulsion method and solidified in the presence of calcium chloride [4], were thus modified with a peptide derived from E-cadherin receptor. Peptide-modified alginate microspheres formed an aggregate in the presence of MSCs, resulted in excellent cell viability, and promoted chondrogenesis in vitro. This approach may find useful applications in 3-D stem cell culture and tissue engineering.
多糖具有良好的生物相容性，是生物医学领域广泛应用的材料之一。然而，大多数基于多糖的水凝胶通常是在可能引起毒性的赋形化学试剂存在的情况下制备的。在本报告中，我们报告了如何制备透明质酸水凝胶，而不使用有毒的化学交联剂。透明质酸是由β-1,4- d-葡萄糖醛酸-β-1,3- n -乙酰- d-葡萄糖胺残基组成，在滑液和细胞外基质中含量丰富。我们将海藻酸盐引入透明质酸骨架，允许在钙离子存在下形成凝胶[1]。水凝胶的力学性能随多糖种类和浓度的不同而变化。利用这些水凝胶将原代软骨细胞/水凝胶构建物皮下注射到小鼠模型中进行组织再生。此外，利用水凝胶控制干细胞表型已被广泛研究，使用细胞指导聚合物对调节间充质干细胞(MSCs)的增殖和分化至关重要[2]。在本报告中，我们报告了一个仿生系统，通过使用细胞引导藻酸盐微球提供干细胞生态位来培养间充质干细胞。MSCs的成软骨分化通常受到聚集形成的影响[3]，钙粘蛋白是干细胞凝聚和成软骨过程中介导细胞间相互作用的关键因子。采用油包水乳液法制备海藻酸盐微球，并在氯化钙存在下固化[4]，用E-cadherin受体衍生的肽修饰海藻酸盐微球。肽修饰的海藻酸盐微球在MSCs存在下形成聚集体，导致良好的细胞活力，并促进体外软骨形成。这种方法可能会在三维干细胞培养和组织工程中找到有用的应用。
{"title":"Polysaccharide-Based Hydrogels for Tissue Engineering","authors":"Jaewon Lee, Hyoseok An, K. Lee","doi":"10.11159/NDDTE16.112","DOIUrl":"https://doi.org/10.11159/NDDTE16.112","url":null,"abstract":"Extended Abstract Polysaccharide is one of widely utilized materials in biomedical areas due to its excellent biocompatibility. However, most polysaccharide-based hydrogels are typically prepared in the presence of excipient chemical reagents that may cause toxicity. In this presentation, we report how hyaluronate hydrogels can be prepared without toxic chemical cross-linking agents. Hyaluronate is composed of β-1,4-D-glucuronic acid-β-1,3-N-acetyl-D-glucosamine residues, and is abundant in synovial fluid and extracellular matrix. We introduced alginate to the hyaluronate backbone, allowing gel formation in the presence of calcium ions [1]. The mechanical properties of hydrogels were varied depending on type and concentration of polysaccharide. Tissue regeneration using these hydrogels were carried out by subcutaneous injection of primary chondrocyte/hydrogel constructs into a mouse model. In addition, a control of stem cell phenotype using hydrogels has been extensively investigated, and a use of cellinstructive polymers is critical to regulate the proliferation and differentiation of mesenchymal stem cells (MSCs) [2]. In this presentation, we report a biomimetic system to culture MSCs by providing stem cell niche using cell-instructive alginate microspheres. Chondrogenic differentiation of MSCs is typically influenced by aggregate formation [3] and cadherin is a key factor in mediating cell-cell interactions during stem cell condensation and chondrogenesis. Alginate microspheres, prepared by the water-in-oil emulsion method and solidified in the presence of calcium chloride [4], were thus modified with a peptide derived from E-cadherin receptor. Peptide-modified alginate microspheres formed an aggregate in the presence of MSCs, resulted in excellent cell viability, and promoted chondrogenesis in vitro. This approach may find useful applications in 3-D stem cell culture and tissue engineering.","PeriodicalId":31009,"journal":{"name":"RAN","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89511101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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