DIRECT PATTERNING OF NATURE-INSPIRED SURFACES FOR BIOINTERFACIAL APPLICATIONS

There are three major challenges for the design of patterned surfaces for biointerfacial applications: (i) durability of antibacterial/antifouling mechanisms, (ii) mechanical durability, and (iii) lifetime of the master mold for mass production of patterned surfaces. In this dissertation, we describe our contribution for the development of each of these challenges. The bioinspired surface, Sharklet AFTM, has been shown to reduce bacterial attachment via a biocide-free structure-property relationship effectively. Unfortunately, the effectiveness of polymer-based sharkskin surfaces is challenged over the long term by both eventual bacteria accumulation and a lack of mechanical durability. To address these common modes of failure, hard, multifunctional, antifouling, and antibacterial shark-skin patterned surfaces were fabricated via a solvent-assisted imprint patterning technique. A UV-crosslinkable adhesive material was loaded with titanium dioxide (TiO2)nanoparticles (NPs) from which shark skin microstructures were imprinted on a polyethylene terephthalate substrate. Furthermore, hard, multifunctional, antifouling, and antibacterial shark skin patterned surfaces were fabricated using inks comprised of zirconium dioxide (ZrO2) NPs and TiO2 NPs. The ZrO2 NPs provide an extremely hard and durable matrix in the final structure, while the TiO2 NPs provide active antibacterial functionality in the presence of UV light via photooxidation. The dynamic water contact angle, mechanical, antibacterial, and antifouling characteristics of the shark skin patterned surfaces were investigated as a function of TiO2 content. We then demonstrated the multifunctional shark skin system’s suitability for use as an antifouling biosensor. Lastly, we described the design of a durable, hard master mold for pattern transfer. The lifetime of many of the current molds is limited by a lack of mechanical durability as well as cost. In this study, ZrO2 NPs were imprinted on a variety of substrates using a solvent-assisted patterning technique and subsequently annealed to increase the mechanical durability of the mold. Polymer replications were demonstrated using the hard ZrO2 mold with thermal and UV nanoimprinting lithography techniques, and injection molding. After up to 115,000 injection molding cycles, there was no delamination or breakage in the ZrO2 mold. The high hardness and durability, as demonstrated through the many replication cycles, suggests that the ZrO2 mold has excellent potential for use in the mass production of patterned polymer replicas. We also explored the nanopatterning of stainless steel using the ZrO2 mold. The solution-processability and simple patterning technique of ZrO2 NPs enable large-area and cost-effective fabrication of the hard molds which can be used for the variety of nano and micro-replication technologies

Utjecaj dodatka praha sluzi chia sjemenki (Salvia hispanica L.) na neka fizikalno-kemijska i reološka svojstva ayrana

In this study, chia seed mucilage powder (MP) was added into ayran drinks at different ratios (0.05, 0.10 and 0.15%, w/v), and its effect on physicochemical, rheological, microbiological and sensory properties of ayran drinks was determined during 10 days of storage at 4±1 °C. MP addition did not influence their major chemical composition significantly (p>0.05). Increasing MP ratio in drinks decreased the colour L* values of drinks while increasing their colour a* and b* values. Addition of 0.05, 0.10 and 0.15% MP reduced serum separation values of drinks by 25, 67 and 83%, respectively. The apparent viscosity value of control samples was 103.20 cP and increased to 134.25, 185.35 and 223.38 cP in ayran drinks with 0.05, 0.10 and 0.15% MP, respectively. The obtained results indicated that chia seed MP up to 0.05% can be used in ayran drink production to reduce serum separation and improve viscosity without any adverse effect on sensory liking scores.U ovom istraživanju, prah sluzi chia sjemenki (MP) dodan je u ayran napitke u različitim omjerima (0,05, 0,10 i 0,15 %, w/v) te je ispitivan njegov učinak na fizikalno-kemijska, reološka, mikrobiološka i senzorska svojstva ayran napitaka tijekom 10 dana skladištenja na 4±1 °C. Dodatak MP nije značajno utjecao na njihov glavni kemijski sastav (p>0,05). Povećanje omjera MP u pićima smanjilo je L* vrijednosti boje pića dok je povećalo njihove a* i b* vrijednosti boje. Dodatak 0,05, 0,10 i 0,15 % MP smanjio je vrijednosti sinereze napitaka za 25, 67 odnosno 83 %. Prividna viskoznost kontrolnih uzoraka bila je 103,20 cP i porasla je na 134,25, 185,35 i 223,38 cP u ayran napicima s 0,05, 0,10 i 0,15 % MP. Rezultati su pokazali da se MP chia sjemenki do 0,05 % može koristiti u proizvodnji ayrana, kako bi se smanjila sinereza i poboljšala viskoznost bez ikakvih negativnih učinaka na senzorska svojstva

Gecko-Inspired Biocidal Organic Nanocrystals Initiated from a Pencil-Drawn Graphite Template

The biocidal properties of gecko skin and cicada wings have inspired the synthesis of synthetic surfaces decorated with high aspect ratio nanostructures that inactivate microorganisms. Here, we investigate the bactericidal activity of oriented zinc phthalocyanine (ZnPc) nanopillars grown using a simple pencil-drawn graphite templating technique. By varying the evaporation time, nanopillars initiated from graphite that was scribbled using a pencil onto silicon substrates were optimized to yield a high inactivation of the Gram-negative bacteria, Escherichia coli. We next adapted the procedure so that analogous nanopillars could be grown from pencil-drawn graphite scribbled onto stainless steel, flexible polyimide foil, and glass substrates. Time-dependent bacterial cytotoxicity studies indicate that the oriented nanopillars grown on all four substrates inactivated up to 97% of the E. coli quickly, in 15 min or less. These results suggest that organic nanostructures, which can be easily grown on a broad range of substrates hold potential as a new class of biocidal surfaces that kill microbes quickly and potentially, without spreading antibiotic-resistance genes

Photonic Resins: Designing Optical Appearance via Block Copolymer Self-Assembly.

Despite a huge variety of methodologies having been proposed to produce photonic structures by self-assembly, the lack of an effective fabrication approach has hindered their practical uses. These approaches are typically limited by the poor control in both optical and mechanical properties. Here we report photonic thermosetting polymeric resins obtained through brush block copolymer (BBCP) self-assembly. We demonstrate that the control of the interplay between order and disorder in the obtained photonic structure offers a powerful tool box for designing the optical appearance of the polymer resins in terms of reflected wavelength and scattering properties. The obtained materials exhibit excellent mechanical properties with hardness up to 172 MPa and Young's modulus over 2.9 GPa, indicating great potential for practical uses as photonic coatings on a variety of surfaces

Volume CXIV, Number 4, November 7, 1996

Objective: Turner syndrome (TS) is a chromosomal disorder caused by complete or partial X chromosome monosomy that manifests various clinical features depending on the karyotype and on the genetic background of affected girls. This study aimed to systematically investigate the key clinical features of TS in relationship to karyotype in a large pediatric Turkish patient population.Methods: Our retrospective study included 842 karyotype-proven TS patients aged 0-18 years who were evaluated in 35 different centers in Turkey in the years 2013-2014.Results: The most common karyotype was 45,X (50.7%), followed by 45,X/46,XX (10.8%), 46,X,i(Xq) (10.1%) and 45,X/46,X,i(Xq) (9.5%). Mean age at diagnosis was 10.2±4.4 years. The most common presenting complaints were short stature and delayed puberty. Among patients diagnosed before age one year, the ratio of karyotype 45,X was significantly higher than that of other karyotype groups. Cardiac defects (bicuspid aortic valve, coarctation of the aorta and aortic stenosis) were the most common congenital anomalies, occurring in 25% of the TS cases. This was followed by urinary system anomalies (horseshoe kidney, double collector duct system and renal rotation) detected in 16.3%. Hashimoto's thyroiditis was found in 11.1% of patients, gastrointestinal abnormalities in 8.9%, ear nose and throat problems in 22.6%, dermatologic problems in 21.8% and osteoporosis in 15.3%. Learning difficulties and/or psychosocial problems were encountered in 39.1%. Insulin resistance and impaired fasting glucose were detected in 3.4% and 2.2%, respectively. Dyslipidemia prevalence was 11.4%.Conclusion: This comprehensive study systematically evaluated the largest group of karyotype-proven TS girls to date. The karyotype distribution, congenital anomaly and comorbidity profile closely parallel that from other countries and support the need for close medical surveillance of these complex patients throughout their lifespa

Effect of chia (Salvia hispanica L.) seed mucilage powder on some physicochemical and rheological properties of ayran drinks

In this study, chia seed mucilage powder (MP) was added into ayran drinks at different ratios (0.05, 0.10 and 0.15%, w/v), and its effect on physicochemical, rheological, microbiological and sensory properties of ayran drinks was determined during 10 days of storage at 4±1 °C. MP addition did not influence their major chemical composition significantly (p>0.05). Increasing MP ratio in drinks decreased the colour L* values of drinks while increasing their colour a* and b* values. Addition of 0.05, 0.10 and 0.15% MP reduced serum separation values of drinks by 25, 67 and 83%, respectively. The apparent viscosity value of control samples was 103.20 cP and increased to 134.25, 185.35 and 223.38 cP in ayran drinks with 0.05, 0.10 and 0.15% MP, respectively. The obtained results indicated that chia seed MP up to 0.05% can be used in ayran drink production to reduce serum separation and improve viscosity without any adverse effect on sensory liking scores

Is pregnancy associated plasma protein-A (PAPP-A) a marker for adverse perinatal outcomes in preterm isolated oligohydramnios cases?

Objective: Isolated oligohydramnios is defined as an amniotic fluid index below five centimeter with no other coexisting condition. There are still controversies about the management and pregnancy outcomes. A marker predicting these is crucial. Low pregnancy associated plasma protein-A levels were reported to be related with adverse pregnancy outcomes. We aimed to determine the role of first trimester pregnancy associated plasma protein-A for poor outcomes in preterm isolated oligohydramnios cases. Material and Methods: Fifty-one patients with singleton pregnancies diagnosed as isolated oligohydramnios at 28/0–36/6 weeks of gestation and 110 gestational age matched healthy controls between January and December 2015 were included. Maternal age, gestational age at delivery, mode of delivery, indication for cesarean section, Apgar scores at first and fifth minutes, birth weight, neonatal intensive care unit admission and mortality were recorded. Pregnancy associated plasma protein-A levels were compared between groups and its role in adverse perinatal outcomes was evaluated. Results: Pregnancy associated plasma protein-A levels and pregnancy outcomes were similar in two groups (p > 0.050) except birth weight, gestational age at delivery and presence of fetal distress. Pregnancy associated plasma protein-A levels did not differ in terms of delivery mode, presence of fetal distress, first and fifth minutes Apgar scores and neonatal intensive care unit admission (p = 0.323,0.650,0.990,0.112,0.853). Also, it was not determined as a risk factor for cesarean section, presence of fetal distress, low Apgar scores and neonatal intensive care unit admission. Conclusion: Pregnancy associated plasma protein-A, a well-known prognostic factor for some of high risk pregnancy conditions, may not be used as a marker in preterm isolated oligohydramnios cases

Bioinspired Photocatalytic Shark-Skin Surfaces with Antibacterial and Antifouling Activity via Nanoimprint Lithography

By combining antifouling shark-skin patterns with antibacterial titanium dioxide (TiO₂) nanoparticles (NPs), we present a simple route toward producing durable multifunctional surfaces that decrease microbial attachment and inactivate attached microorganisms. Norland Optical Adhesive, a UV-crosslinkable adhesive material, was loaded with 0, 10, or 50 wt % TiO₂ NPs from which shark-skin microstructures were imprinted using solvent-assisted soft nanoimprint lithography on a poly­(ethylene terephthalate) (PET) substrate. To obtain coatings with an exceptional durability and an even higher concentration of TiO₂ NPs, a solution containing 90 wt % TiO₂ NPs and 10 wt % tetraethyl orthosilicate was prepared. These ceramic shark-skin-patterned surfaces were fabricated on a PET substrate and were quickly cured, requiring only 10 s of near infrared (NIR) irradiation. The water contact angle and the mechanical, antibacterial, and antifouling characteristics of the shark-skin-patterned surfaces were investigated as a function of TiO₂ composition. Introducing TiO₂ NPs increased the contact angle hysteresis from 30 to 100° on shark-skin surfaces. The hardness and modulus of the films were dramatically increased from 0.28 and 4.8 to 0.49 and 16 GPa, respectively, by creating ceramic shark-skin surfaces with 90 wt % TiO₂ NPs. The photocatalytic shark-skin-patterned surfaces reduced the attachment of Escherichia coli by ∼70% compared with smooth films with the same chemical composition. By incorporating as low as 10 wt % TiO₂ NPs into the chemical matrix, over 95% E. coli and up to 80% Staphylococcus aureus were inactivated within 1 h UV light exposure because of the photocatalytic properties of TiO₂. The photocatalytic shark-skin-patterned surfaces presented here were fabricated using a solution-processable and roll-to-roll compatible technique, enabling the production of large-area high-performance coatings that repel and inactivate bacteria