Tungsten-ethylene vinyl acetate (EVA) composite as a gamma rays shielding material

Lead is a highly toxic metal, also heavy in personal shielding. This negative aspect decline us to search for alternative shielding material that is free of toxic effect, environment friendly, lighter and easy to use individually. Polymer, being lighter, may constitute an alternative to lead, but it has a much lower density and does not serve in gamma shielding by it. Therefore, high density tungsten could be added to polymer in order to shield gamma rays. In this study ethylene vinyl acetate (EVA) and tungsten were mixed in certain amounts and thus discs have been produced from this mixture. The results show that EVA-Tungsten composite is an effective shielding material for gamma shielding

Titanyum implantlarına antibiyotik yüklenmesi ve biyoaktivitelerinin değerlendirilmesi

Bazı omurga hastalıklarının tedavisi için cerrahi müdahale gerekir. Omurga implantları kullanılarak omurganın stabilitesi, iki omurun füzyonu ile sağlanabilir. Böylece omurilik güçlendirilir ve deformasyonlar düzeltilir. Titanyum ve alaşımları, uygun biyouyumluluk özellikleri, hafif ve dayanıklı olmaları ve osseointegrasyonu destekleyici kapasiteleri nedeniyle omurga implantları için en sık kullanılan malzemelerdir. Bununla birlikte, omurga implantlarının başarılı bir performansa sahip olması, implant bölgesinin çevresinde enfeksiyon bulunmamasına da bağlıdır. Bu durumun önlenmesi için, gentamisin sülfat, hem gram pozitif hem de gram negatif bakterilerdeki etkinliği sayesinde lokal tedavi için yaygın olarak kullanılan bir antibiyotiktir. Bu çalışmada, hücre büyümesini ve çoğalmasını arttırdığı bilinen biyouyumlu bir doğal polisakarit olan agaroz (Agr) ve agaroz ile çapraz bağ oluşturabilen doğal bir katekol olan tannik asit (TA) içeren bir hidrojel hazırlanarak titanyum disklerin üzerine kaplanmıştır. Agr'nin gentamisin sülfat (GS) ile yüklenmesiyle, Ti6Al4V yüzeylerinde antibakteriyel aktivite sağlanırken aynı zamanda osseointegrasyon hızını arttırıcı etki oluşturması hedeflenmiştir. 14 mm çapındaki kumlamalı Ti6Al4V diskler, temizlendikten sonra 2,5 M sodyum hidroksit (NaOH) çözeltisi ile yüzeylerinde hidroksil grupları oluşturulmuştur. Daha sonra, pH 8,7'de 10 mM Tris tamponu (2 mg/mL) içinde çözülmüş dopamin (DOPA) çözeltisinde 24 saat bekletilerek yüzeylere DOPA aşılaması yapılmıştır. GS yüklemesi için % 1 Agr'den oluşan sulu çözeltisine, saf suda çözülmüş % 0,1 TA, % 0,1 kalsiyum klorür (CaCl2) ve 1 mg/mL GS ilave edilmiştir. Bu karışım daha sonra Ti6Al4V-DOPA yüzeyi üzerine kaplanmış ve 2 saat boyunca UV ışık altında bekletilmiştir. Yüzey modifikasyonlarının etkinliği XPS analizleri, su temas açısı ölçümleri, profilometre analizleri ve hidrojel karakterizasyonu ise FTIR analizleri ile değerlendirilmiştir. Yüzeyin atomik konsantrasyonunu belirlemek için yapılan X-ışını fotoelektron spektroskopisi (XPS) analizleri, DOPA'nın yüzeye başarılı bir şekilde aşılandığını ve Agr'nin yüzeye kaplanmasının da başarılı olduğunu açıkça göstermektedir. Nitekim, Ti6Al4V disklere kıyasla karbon yüzdesi önemli ölçüde yükselmiştir. Aynı zamanda kaplanmış olan disklerde Ti elementine rastlanmamıştır. Ayrıca, GS yüklü Agr'nin Ti6Al4V-DOPA yüzeyine kaplanması, DOPA'dan kaynaklanan azot elementinin XPS analizi sonucunda yüzeyde görülmemesi ile kanıtlanmaktadır. Su temas açısı değerleri ve profilometre analizleri ile Ti6Al4V-DOPA ve Ti6Al4V-Agr'nin homojen olarak aşılanmış olduğunu ve FTIR analizleri ile GS'nin Ti6Al4V yüzeylerinde kaplanan Agr hidrojeline etkin bir şekilde yüklendiği kanıtlanmıştır. GS salımı fizyolojik koşullar altında 28 gün bekletilerek salınan miktar ELISA testi ile belirlenmiştir. 6. saatte ani salım ile gentamisinin büyük bir miktarı salınmıştır. Fakat TA içeren kaplamalarda 21. güne kadar S. aureus bakterileri üzerinde gentamisinin minimum inhibitör konsantrasyonu (MİK) değerinden daha yüksek miktarda salım devam etmiştir. Antibakteriyel testlerde kaplamaların antibakteriyel etkinliği 7. güne kadar test edilmiş ve GS yüklü kaplamaların S. aureus bakterileri üzerinde antibakteriyel etkisi kanıtlanmıştır. Hücre kültürü çalışmalarında farklı içeriklerde Agr ile kaplanmış disklerin biyoaktiviteleri değerlendirilmiştir. Saos-2 hücre hattı üzerinde yapılan indirekt testler sonucunda disklerin hücre canlılığını arttırıcı etki gösterdiği tespit edilmiştir. Ayrıca aynı hücreler üzerinde direkt test yapılmış ve en yüksek miktarda canlı hücre sayısı, içeriğinde GS, TA, CaCl2 bulunan Agr kaplamalı disk yüzeyinde tespit edilmiştir.Surgical intervention is needed for the treatment of some spinal diseases. Using spinal implants, the fusion of two vertebrae can be facilitated, the stability of the spine is by this way ensured, thus the spinal cord strengthened and deformities corrected. Titanium and its alloys are the most widely used materials for spinal implants, due to their suitable properties of biocompatibility, strength-to-weight ratio, and their capacity to prone osseointegration. However, the successful performances of spinal implants also depend on the absence of infections near the implant site. To treat them, gentamicin sulphate (GS), is commonly used for local treatment thanks to its efficiency on both gram positive and gram negative bacteria. For that purpose, Ti6Al4V implant will be coated with a hydrogel based on agarose (Agr), a biocompatible natural polysaccharide, known to improve cell growth and tannic acid (TA), a natural catechol, able to induce crosslink. By loading this hydrogel with gentamicin, the Ti6Al4V surfaces are expected to promote osseointegration whilst presenting antibacterial activity. Sand blasted Ti6Al4V discs, 14 mm diameter, were cleaned before surface activation with 2.5 M NaOH solution. Then, they were let react overnight with dopamine solution (DOPA), dissolved in 10 mM Tris buffer (2 mg/mL) at pH 8.7. Thereafter, gentamicin loading was done as follow: 1 % Agr in water was added to an aqueous solution made of 0.1 % TA, 0.1 % CaCl2 and 1 mg/mL GS. This mixture was then coated on the Ti6Al4V-DOPA surface and let react under UV irradiation for 2h. The efficiency of surface modifications was assessed by X-ray photoelectron spectroscopy XPS analyses, contact angle (CA) measurements, profilometry analyses, and hydrogel characterization was done by FTIR. XPS analyses, allowing to determine the surface atomic concentration clearly exhibit the successful surface grafting of DOPA and Agr. Indeed, carbon percentage is significantly higher when compared to clean Ti6Al4V sample, whereas Ti is no more detected on coated ones. Further, the grafting of GS loaded Agr on Ti6Al4V-DOPA surface is evidenced by the lack of nitrogen from DOPA. Contact angle values also demonstrate the coating presence on surfaces. Profilometry analyses have shown that Ti6Al4V-DOPA and Ti6Al4V-Agr were homogeneously grafted and FTIR analyses have evidenced that GS was efficiency entrapped in the Agr hydrogel coated on Ti6Al4V surfaces. GS release was performed under pseudo-physiological conditions for 28 days and the amount quantified by using ELISA tests. At 6th h, a large amount of gentamicin was released by burst release. But the amount of GS that more than the MIC value of GS on S. aureus bacteria continued to release from TA-containing coatings until day 21. The antibacterial activity of the coatings in antibacterial tests was tested up to day 7 and the GS loaded coatings proved an antibacterial effect on S. aureus bacteria. Bioactivities of discs with Agr coated in different contents were evaluated in cell culture studies. As a result of indirect tests that were performed on Saos-2 cell line, it was determined that the discs showed proliferation effect on cells. In addition, direct testing was performed on the same cell line and the highest number of viable cells was detected on the surface of Agr coated discs containing GS, TA, CaCl2

Tungsten-ethylene vinyl acetate (EVA) composite as a gamma rays shielding material

793-796Lead is a highly toxic metal, also heavy in personal shielding. This negative aspect decline us to search for alternative shielding material that is free of toxic effect, environment friendly, lighter and easy to use individually. Polymer, being lighter, may constitute an alternative to lead, but it has a much lower density and does not serve in gamma shielding by it. Therefore, high density tungsten could be added to polymer in order to shield gamma rays. In this study ethylene vinyl acetate (EVA) and tungsten were mixed in certain amounts and thus discs have been produced from this mixture. The results show that EVA-Tungsten composite is an effective shielding material for gamma shielding

Tungsten-ethylene vinyl acetate (EVA) composite as a gamma rays shielding material

WOS: 000391242400006Lead is a highly toxic metal, also heavy in personal shielding. This negative aspect decline us to search for alternative shielding material that is free of toxic effect, environment friendly, lighter and easy to use individually. Polymer, being lighter, may constitute an alternative to lead, but it has a much lower density and does not serve in gamma shielding by it. Therefore, high density tungsten could be added to polymer in order to shield gamma rays.. In this study ethylene vinyl acetate (EVA) and tungsten were mixed in certain amounts and thus discs have been produced from this mixture. The results show that EVA-Tungsten composite is an effective shielding material for gamma shielding.Ege UniversityEge University [13FBE009]This research was supported by the Ege University, Scientific Research Project (BAP), and Project Number: 13FBE009

Subphthalocyanine as a fluorescence imaging agent for breast tumor

WOS: 000474330400061PubMed ID: 31026614Tri-tert-butyl-carboxyl subphthalocyanine (SubPc) was synthesized and evaluated as a fluorescence agent. Fluorescence imaging for breast tumor in vivo was performed using nude mice as models. Results indicate high uptake in tumor at 20 h. Tumor-non tumor ratio was determined as 2.25. The imaging results demonstrate the potential of this fluorescence-imaging agent in the diagnosis of breast tumor. In the future, subphthalocyanine is also developing as a dual functional, which is fluorescence imaging and as a photodynamic therapeutic agent for the treatment and diagnosis of cancer

Investigation of Vipera Anatolica Venom Disintegrin via Intracellular Uptake with Radiolabeling Study and Cell-Based Electrochemical Biosensing Assay

WOS: 000464733200028PubMed ID: 30276529Snake venoms are a natural biological source that has potential therapeutic value with various protein compounds. Disintegrins originally were discovered as a family of proteins from snake venoms composed of cysteine rich low molecular weight polypeptides. Disintegrins exhibit specific binding and higher affinity toward integrin with potential inhibition of function. Trans-membrane receptors of the integrin family may involve in many pathological conditions such as inflammation and tumor progression with important processes related to invasion and migration. Since disintegrins have the ability to bind to integrins, they could be used for cancer detection and treatment, and in monitoring of therapy in select cancer types. The main purpose of the study is to investigate disintegrin containing Vipera anatolica (VAT) crude venom potential for radiolabeling and intracellular uptake as well as electrochemical biosensing assay against U87MG human brain glioblastoma cells. For this purpose, VAT crude venom containing U87MG cell-specific disintegrin was investigated in terms of radiolabeling and intracellular uptake as well as electrochemical biosensing assay in comparison with echistatin (ECT) disintegrin in cells. The interaction between VAT crude venom and ECT with HEK293 human non-tumorigenic embryonic kidney cells and glioblastoma U87MG cells was electrochemically investigated using pencil graphite electrodes (PGEs). The interaction of the VAT crude venom and ECT with HEK293 and U87MG cells was detected according to the changes in oxidation signals. Then, VAT crude venom and echistatin were labeled with I-131 via iodogen method. Intracellular uptakes of radiolabeled molecules were investigated in U87MG cell line. I-131-VAT can be an agent for imaging of glioblastoma cancer. Further work will focus on the production of large quantities of pure VAT disintegrin with a biotechnological approach to improving imaging agent

Investigation of In vitro PDT Activities and In vivo Biopotential of Zinc Phthalocyanines Using I-131 Radioisotope

WOS: 000370485300007PubMed ID: 26348246Novel octylthio-containing asymmetrically substituted Zn(II) phthalocyanine (Zn(II) Pc1) and a symmetric derivative (Zn(II) Pc2) have been prepared to investigate the biological potential and ability to photosensitize singlet oxygen for photodynamic therapy applications. In this study, the singlet oxygen generation potential and in vitro photodynamic activities of these compounds have been tested. Both ZnPcs reveal to be very efficient singlet oxygen generators and promising PSs for PDT applications. In vitro PDT activities of the compounds were evaluated in EMT-6 murine mammary carcinoma and HeLa human cervix carcinoma cell lines. Moreover, Zn(II) Pc1 displayed the phototoxic effects in the mammary cancer cell line (6.25 mu M concentration at 30 J/cm(2) light dose and 12.5 mu M concentration at 20 J/cm(2) light dose), while Zn(II) Pc2 did not show any phototoxic effects both in two cell lines. Zn (II) Pcs were radiolabeled with I-131 in high yields. Biodistribution studies revealed that the radiolabeled Zn(II) Pc1 showed significant uptake in l. intestine, pancreas, brain, and ovary, while Zn(II) Pc2 has significant uptake in ovary and pancreas in normal rats. Hence, these Pcs derivatives could be promising candidate for tumor nuclear imaging.Scientific and Technological Research Council of Turkey, TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [112T565]The authors gratefully acknowledge financial support by The Scientific and Technological Research Council of Turkey, TUBITAK (Grant no: 112T565)