Spider silk as an active scaffold in the assembly of gold nanoparticles and application of the gold-silk bioconjugate in vapor sensing.

Spider silk is being viewed with interest by materials scientists due to its excellent resilience and mechanical properties. In this paper we show that spider silk is an excellent scaffold for the one-step synthesis and assembly of gold nanoparticles. Formation of a gold nanoparticle-spider-silk bioconjugate material is accomplished by simple reaction of the fibers with aqueous chloroauric acid. The gold nanoparticles thus formed are strongly bound to the spider-silk fiber surface enabling study of the electrical properties of the nanobioconjugate. Using the well-known contraction/expansion behavior of the fibers in solvents of varying polarity, we show that exposure of the gold nanoparticle-spider silk bioconjugate to vapors of methanol and chloroform leads to changes in electrical transport through the nanoparticles and thus, the possibility of developing a vapor sensor. The bioconjugate shows excellent response time and cycling efficiency to methanol vapors. The activation energy of electron transport from one gold nanoparticle to another in the nanobiocojugate was determined from temperature-dependent electron-transport measurements to be approximately 1.7 eV.

Design and characterization of a biodegradable double-layer scaffold aimed at periodontal tissue-engineering applications.

The inefficacy of the currently used therapies in achieving the regeneration ad integrum of the periodontium stimulates the search for alternative approaches, such as tissue-engineering strategies. Therefore, the core objective of this study was to develop a biodegradable double-layer scaffold for periodontal tissue engineering. The design philosophy was based on a double-layered construct obtained from a blend of starch and poly-ε-caprolactone (30:70 wt%; SPCL). A SPCL fibre mesh functionalized with silanol groups to promote osteogenesis was combined with a SPCL solvent casting membrane aiming at acting as a barrier against the migration of gingival epithelium into the periodontal defect. Each layer of the double-layer scaffolds was characterized in terms of morphology, surface chemical composition, degradation behaviour and mechanical properties. Moreover, the behaviour of seeded/cultured canine adipose-derived stem cells (cASCs) was assessed. In general, the developed double-layered scaffolds demonstrated adequate degradation and mechanical behaviour for the target application. Furthermore, the biological assays revealed that both layers of the scaffold allow adhesion and proliferation of the seeded undifferentiated cASCs, and the incorporation of silanol groups into the fibre-mesh layer enhance the expression of a typical osteogenic marker. This study allowed an innovative construct to be developed, combining a three-dimensional (3D) scaffold with osteoconductive properties and with potential to assist periodontal regeneration, carrying new possible solutions to current clinical needs. Copyright © 2013 John Wiley & Sons, Ltd.

"Nano": the new nemesis of cancer.

Materials at nano dimensions exhibit totally different properties compared to their bulk and atomic states. This feature has been harnessed by scientists from various disciplines, to develop functional nanomaterials for cancer diagnosis and therapeutics. The success stories range from delivering chemotherapeutic molecules in nano-sized formulations to functional nanomaterials, which deliver thermal and radiotherapy at specific targeted sites. This brief review summarizes the recent developments of various nanotechnologies in cancer therapy and diagnostics, both from the research sector and the upcoming products in pipeline on its route to commercialization. Supportive engineering innovations and frontiers in nanomolecular research, with a potential to revolutionize cancer therapy, have been discussed in brief.

Thermometry studies of radio-frequency induced hyperthermia on hydrogel based neck phantoms.

A cylindrical phantom, resembling average human neck, was prepared by using hydrogel sheets containing vinyl and polysaccharide. The phantom was used to obtain temperature distributions for 6 values of input power of radio frequency (RF) at 8MHz,by invasive thermometry technique, using thermistor probes. The inclusion of cervical vertebrae and calcium carbonate pieces (human bone representative) with a hollow tube (windpipe equivalent) in the phantom simulates the change in thermal distributions. This is similar to the alterations in heat disposition obtained in the real human neck, during RF induced heating, without extensive distortion of the uniform temperature distribution provided by the RF heating instrument. This paper compares the hydrogel neck phantom with other phantoms, that have been developed for studying thermal distributions and optimization of novel non invasive thermometry techniques in hyperthermic oncology.