Effect of terephthalic acid functionalized graphene oxide on the molecular interaction, and mechanical and thermal properties of Hytrel polymer.

We report the effect of incorporating functionalized graphene oxide (terephthalic acid functionalized GO; GO-g-TPA) on the thermal and mechanical properties of Hytrel (HTL; a thermoplastic elastomeric polymer). Initially, the synthesis of GO-g-TPA was performed via chemical methods and subsequently characterized using various spectroscopic and imaging techniques. The melt mixing technique was executed in preparing the nanocomposites of HTL/GO and HTL/GO-g-TPA. An excellent GO dispersion was observed in the HTL polymeric matrix, which could be attributed to the significant effect of hydrogen bonding and π-π interaction between the HTL and GO-g-TPA. As a result of incorporating GO and GO-g-TPA into the HTL matrix, the overall mechanical and thermal properties of the nanocomposites were significantly improved. For the HTL/5 wt% GO-g-TPA nanocomposite, the tensile strength and storage modulus significantly increased by 61% and 224%, respectively. In addition, the melting temperature and crystalline temperature are increased by a notable 20 °C and 21 °C, respectively. Thus, the current study found that by improving the dispersion ability of the GO sheets, the properties of the HTL can be significantly enhanced and the prepared composite materials can be relevant for a wide range of applications including sports goods, hose jackets, wire and cable jackets, electronics, fluid power, sheeting belting seals, and footwear, etc.

Functionalized graphene oxides for drug loading, release and delivery of poorly water soluble anticancer drug: A comparative study.

In this work, the modification of graphene oxides (GOs) have been done with hydrophilic and biodegradable polymer, polyvinylpyrrolidone (PVP) and other excipient ß -cyclodextrin (ß-CD) through covalent functionalization for efficient loading and compatible release of sparingly water soluble aromatic anticancer drug SN-38 (7-ethyl-10-hydroxy camptothecin). The drug was loaded onto both GO-PVP and GO-ß-CD through the π-π interactions.The release of drug from both the nanocarriers were analyzed in different pH medium of pH 7 (water, neutral medium), pH 5 (acidic buffer) and pH 12 (basic buffer). The loading capacity and the cell killing activity of SN-38 loaded on functionalized GO were investigated comprehensively in human breast cancer cells MCF-7.Our findings shown that the cytotoxicity of SN-38 loaded to the polymer modified GO was comparatively higher than free SN-38. In particular, SN-38 loaded GO-PVP nanocarrier has more cytotoxic effect than GO-ß-CD nanocarrier against MCF-7 cells, indicating that SN-38 loaded GO-PVP nanocarrier can be used as promising material for drug delivery and biological applications.

Novel on-demand bioadhesion to soft tissue in wet environments.

Current methods of tissue fixation rely on mechanical-related technologies developed from the clothing and carpentry industries. Herein, a novel bioadhesive method that allows tuneable adhesion and is also applicable to biodegradable polyester substrates is described. Diazirine is the key functional group that allows strong soft tissue crosslinking and on-demand adhesion based on a free radical mechanism. Plasma post-irradiation grafting makes it possible to graft diazirine onto PLGA substrates. When the diazirine-PLGA films, placed on wetted ex vivo swine aortas, are activated with low intensity UV light, lap shear strength of up to 450 ± 50 mN cm(-2) is observed, which is one order of magnitude higher than hydrogel bioadhesives placed on similar soft tissues. The diazirine-modified PLGA thin films could be added on top of previously developed technologies for minimally invasive surgeries. The present work is focused on the chemistry, grafting, and lap shear strength of the alkyl diazirine-modified PLGA bioadhesive films.

Contraception in India: exploring met and unmet demand.

Our study examines factors influencing demand for contraception for spacing as well as for limiting births in India. Data on socio-economic, demographic and program factors affecting demand for contraception in India are from the National Family Health Survey, 1998--99. The recent document from the National Rural Health Mission has completely ignored the use of contraception in controlling fertility in India. Empirical results of our study suggest giving priority to and focusing attention on supply-side factors such as a regular and sustained supply of quality contraceptive methods to improve accessibility and affordability. Further, strengthening the information, education and communication (IEC) component of the reproductive and child health (RCH) package would allay misapprehensions about the side effects and health risks of contraception. Focusing attention on demand-side factors such as women's empowerment through education, gainful employment and exposure to mass-media would help reduce the unmet demand for family planning. The resulting reduction in fertility would hasten the process of demographic transition and population stabilization in India.