Raman Spectroscopy as a Predictive Tool for Monitoring Osteoporosis Therapy in a Rat Model of Postmenopausal Osteoporosis

Pharmacological therapy of osteoporosis reduces bone loss and risk of fracture in patients. Modulation of bone mineral density cannot explain all effects. Other aspects of bone quality affecting fragility and ways to monitor them need to be better understood. Keratinous tissue acts as surrogate marker for bone protein deterioration caused by oestrogen deficiency in rats. Ovariectomised rats were treated with alendronate (ALN), parathyroid hormone (PTH) or estrogen (E2). MicroCT assessed macro structural changes. Raman spectroscopy assessed biochemical changes. Micro CT confirmed that all treatments prevented ovariectomy-induced macro structural bone loss in rats. PTH induced macro structural changes unrelated to ovariectomy. Raman analysis revealed ALN and PTH partially protect against molecular level changes to bone collagen (80% protection) and mineral (50% protection) phases. E2 failed to prevent biochemical change. The treatments induced alterations unassociated with the ovariectomy; increased beta sheet with E2, globular alpha helices with PTH and fibrous alpha helices with both ALN and PTH. ALN is closest to maintaining physiological status of the animals, while PTH (comparable protective effect) induces side effects. E2 is unable to prevent molecular level changes associated with ovariectomy. Raman spectroscopy can act as predictive tool for monitoring pharmacological therapy of osteoporosis in rodents. Keratinous tissue is a useful surrogate marker for the protein related impact of these therapies. The results demonstrate utility of surrogates where a clear systemic causation connects the surrogate to the target tissue. It demonstrates the need to assess broader biomolecular impact of interventions to examine side effects. [Figure not available: see full text.]

Raman Spectroscopy Predicts the Link between Claw Keratin and Bone Collagen Structure in a Rodent Model of Oestrogen Deficiency

Osteoporosis is a common disease characterized by reduced bone mass and an increased risk of fragility fractures. Low bone mineral density is known to significantly increase the risk of osteoporotic fractures; however, the majority of non-traumatic fractures occur in individuals with a bone mineral density too high to be classified as osteoporotic. Therefore, there is an urgent need to investigate aspects of bone health, other than bone mass, that can predict the risk of fracture. Here, we successfully predicted association between bone collagen and nail keratin in relation to bone loss due to oestrogen deficiency using Raman spectroscopy. Raman signal signature successfully discriminated between ovariectomised rats and their sham controls with a high degree of accuracy for the bone (sensitivity 89%, specificity 91%) and claw tissue (sensitivity 89%, specificity 82%). When tested in an independent set of claw samples the classifier gave 92% sensitivity and 85% specificity. Comparison of the spectral changes occurring in the bone tissue with the changes occurring in the keratin showed a number of common features that could be attributed to common changes in the structure of bone collagen and claw keratin. This study established that systemic oestrogen deficiency mediates parallel structural changes in both the claw (primarily keratin) and bone proteins (primarily collagen). This strengthens the hypothesis that nail keratin can act as a surrogate marker of bone protein status where systemic processes induce changes

SERS Detection of Hg2+ using Rhenium Carbonyl Labelled Nanoparticle Films

Modified silver nanoparticles with a self-assembled disulfide functionalized 2,2´-bipyridine (L1 and L2) monolayer, and the corresponding rhenium complex [Re(L2)(CO)3Br] are shown to provide a method to position the nanoparticles at a water/dichloromethane interface forming a lustrous metal-like-liquid film (MeLLF) with a unique SERs response. The film formed using L2 showed divergent behavior in the presence of a range of metal ions whilst bound to the surface. [Re(L)(CO)3Br] (where L = 2,2´-bipyridine, L1 and L2) in solution demonstrates a selective interaction with Hg2+, observed by UV-vis, emission and 1H NMR spectroscopy, attributed to abstraction of the bromide. This interaction was demonstrated by subtle changes in the characteristic Raman Re-CO stretch at 510 cm 1 both with the MeLLF, and when the film is immobilized in a PVA surface-exposed-nano-sheet (SENS). The work provides proof of concept that the organometallic complexes can be employed as “labels” to generate SERS-active nanoparticle films that possess detection capabilities

Properties of super-hydrophobic copper and stainless steel meshes: applications in controllable water permeation and organic solvents/water separation

The wettability and hydrophobicity of super-hydrophobic (SH) meshes is greatly influenced by their topographic structures, chemical composition and coating process. In this study, the properties of copper and stainless steel meshes, coated with super-hydrophobic electrolessly deposited silver were investigated. A new method to test the pressure resistance of super-hydrophobic mesh was applied to avoid any deformation of mesh. Results showed that SH copper mesh and SH stainless steel meshes with the same pore size have almost the same contact angle and the same hydrophobicity. SH copper mesh with a pore size of 122 pin can resist water pressure of 4900 Pa and a decrease of pore size of mesh can increase the pressure resistance of SH copper mesh. The SH copper mesh modified with 0.1 M HS(CH2)(10)COOH solution in ethanol has a controllable water permeation property by simply adjusting the pH of water solution. SH copper mesh shows super-oleophilicity with organic solvents and so with a water contact angle of 0 and it can be an effective tool for organic solvents/water separation. The separation efficiency of SH copper mesh for separating mixtures of organic solvent and water can be as high as 99.8%. (C) 2015 Elsevier B.V. All rights reserved.peer-reviewe