In vitro comparison of nanofibrillar and macroporous-spongious composite tissue scaffolds for periodontal tissue engineering.

PURPOSE/AIM OF THE STUDY: The ultimate goal of periodontal treatment is to regenerate the lost periodontal tissues. The interest in nanomaterials in dentistry is growing rapidly and has focused on improvements in various biomedical applications, such as periodontal regeneration and periodontal tissue engineering. To enhance periodontal tissue regeneration, hydroxyapatite (HA) was used in conjunction with other scaffold materials, such as Poly lactic-co-glycolic-acid (PLGA) and collagen (C). The main target of this study was to compare the effects of nano and macrostructures of the tissue scaffolds on cell behavior in vitro for periodontal tissue engineering. MATERIALS AND METHODS: Nanofibrillar and macroporous-spongious composite tissue scaffolds were produced using PLGA/C/HA. Subgroups with BMP-2 signal molecule and without HA were also created. The scaffolds were characterized by FTIR, SEM/EDX techniques, and mechanical tests. The scaffolds were compared in the periodontal ligament (PDL) and MCT3-E1 cell cultures. The cell behaviors; adhesions by SEM, proliferation by WST-1, differentiation by ALP and mineralization with Alizarin Red Tests were determined. RESULTS: Cell adhesion and mineralization were higher in the nanofibrillar scaffolds compared to the macroporous-spongious scaffolds. Macroporous-spongious scaffolds seemed better for the proliferation of PDL cells and differentiation of MC3T3-E1-preosteoblastic cells, while nanofibrillar scaffolds were more convenient for the differentiation of PDL cells and proliferation of MC3T3-E1-preosteoblastic cells. CONCLUSIONS: In general, nanofibrillar scaffolds showed more favorable results in cell behaviors, compared to the macroporous-spongious scaffolds, and mostly, BMP-2 and HA promoted the activities of the cells.

Application of ATR-FTIR spectroscopy and chemometrics for the discrimination of human bone remains from different archaeological sites in Turkey.

Examining diagenetic parameters such as the organic carbonate contents and the crystallinity of bone apatite quantify the post-mortem alteration of bone. Burial conditions are one of the factors that can influence the diagenesis process. We studied the changes to the organic and mineral components and crystallinity of human bone remains from five Medieval sites in Turkey: Hakemi Use, Komana, Iznik, Oluz Höyük and Tasmasor using Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR) and principal component analysis (PCA). Analysis of spectral band ratios related to organic and mineral components of bone demonstrated differences in the molecular content in the skeletal remains from the five sites. In order to examine the degree of carbonation of a phosphate matrix, curve-fitting procedures were applied to the carbonate band. We found that the infrared crystallinity index appears to not be sensitive to carbonate content at room temperature for the bone remains studied here. The recrystallization process in bone remains behaved differently among the archaeological sites. The results demonstrate that the burial environments differently affect the organic and mineral components of archaeological bone remains.

Conformational and vibrational studies of arachidonic acid, light and temperature effects on ATR-FTIR spectra.

Arachidonic acid (AA) (cis,cis,cis,cis-5,8,11,14-Eicosatetraenoic acid) is an omega-6 polyunsaturated fatty acid (PUFA) constituent of the phospholipids of cell membranes. The conformational behavior of AA in the gas phase was investigated by means of density functional theory (DFT) using B3LYP method with 6-311++G(d,p) basis set. Theoretical calculations on the structures and infrared spectra of monomer conformers and dimer form of the most stable monomer conformer of AA were performed. Vibrational assignment of the fundamental modes was made based on calculated potential energy distribution (PED). Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectrum of AA in liquid phase was recorded in the region 4000-450 cm-1. The theoretical spectrum of dimer AA in gas phase is in reasonably good agreement with the experimental liquid phase spectrum. The double bonds in unsaturated fatty acids are prone to oxidation. Oxidized PUFAs lead to adverse health effects. The effects of daylight and temperature on the oxidative stability of AA were investigated using ATR-FTIR spectroscopy. The analysis reveals that the light and thermal treatment induce cis-trans isomerization in AA.

Structural studies on Demospongiae sponges from Gökçeada Island in the Northern Aegean Sea.

The Demospongiae is the largest Class in the phylum Porifera (sponges). Most sponge species in the Class Demospongiae have a skeleton of siliceous spicules and/or protein spongin or both. The first aim of this study was to perform the morphological and structural characterization of the siliceous spicules of four species belonging to Class Demospongiae (Suberites domuncula, Axinella polypoides, Axinella damicornis and Agelas oroides) collected around Gökçeada Island-Turkey (Northern Aegean Sea). The characterizations were carried out using a combination of Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM/EDX), Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Small Angle X-ray Scattering (SAXS) techniques. The sponge Chondrosia reniformis (Porifera, Demospongiae) lacks a structural skeleton of spicules or the spongin. It consists mainly of a collagenous tissue. The collagen with sponge origin is an important source in biomedical and pharmaceutical applications. The second aim of this study was to provide more information on the molecular structure of collagen of outer (ectosome) and inner (choanosome) regions of the Chondrosia reniformis using ATR-FTIR spectroscopy. Hierarchical clustering analysis (HCA) was also used for the discrimination of ATR-FTIR spectra of species.

Micro- and nano-structural characterization of six marine sponges of the class Demospongiae.

The sponges produce their skeletal elements and silicateins are the key enzymes in this process. The mechanism underlying the formation of their silica skeleton and its structural properties are of exceptional interest for applications in technology. Micro- and nano-scale structural analysis of the six marine sponges belonging to Demospongiae [Callyspongia (Cladochalia) plicifera (Lamarck, 1814), Cervicornia cuspidifera (Lamarck, 1815), Cinachyrela sp., Niphates erecta (Duchassaing and Michelotti, 1864), Xestospongia muta (Schmidt, 1870) and Amphimedon compressa (Duchassaing and Michelotti, 1864)] were carried out by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) and Small-Angle X-ray Scattering (SAXS) techniques. The nano-structural characterizations give some informative evidence about the manner in which silica/silicatein in spicule skeletons is produced by the sponges. The sponge species were successfully discriminated using cluster analysis (HCA) based on FTIR spectra. This study demonstrates and detection of structural differences among sponges and their spicules using combined techniques.

Structural effects of simvastatin on liver rat [corrected] tissue: Fourier transform infrared and Raman microspectroscopic studies.

Simvastatin is one of the most frequently prescribed statins because of its efficacy in the treatment of hypercholesterolemia, reducing cardiovascular risk and related mortality. Determination of its side effects on different tissues is mandatory to improve safe use of this drug. In the present study, the effects of simvastatin on molecular composition and structure of healthy rat livers were investigated by Fourier transform infrared and Raman imaging. Simvastatin-treated groups received 50 mg/kg/day simvastatin for 30 days. The ratio of the area and/or intensity of the bands assigned to lipids, proteins, and nucleic acids were calculated to get information about the drug-induced changes in tissues. Loss of unsaturation, accumulation of end products of lipid peroxidation, and alterations in lipid-to-protein ratio were observed in the treated group. Protein secondary structure studies revealed significant decrease in α-helix and increase in random coil, while native ß-sheet decreases and aggregated ß-sheet increases in treated group implying simvastatin-induced protein denaturation. Moreover, groups were successfully discriminated using principal component analysis. Consequently, high-dose simvastatin treatment induces hepatic lipid peroxidation and changes in molecular content and protein secondary structure, implying the risk of liver disorders in drug therapy.

Micro- and nanoscale structures of mesiodens dentin: Combined study of FTIR and SAXS/WAXS techniques.

A mesiodens is the most common type of supernumerary tooth present in conjunction to normal dentition. A mesiodens may commonly occur in the central region of the upper or lower jaw. A mesiodens is different from normal teeth in terms of structure and shape. The aim of this study is to evaluate the micro- and nanoscale structural properties of mesiodens dentin by combined small- and wide-angle X-ray scattering (SAXS/WAXS) and Fourier transform infrared (FTIR) spectroscopy. Five freshly extracted, noncarious mesiodens and five normal dentin disks prepared from human incisor teeth were compared. Using FTIR, the phosphate-to-amide I, carbonate-to-phosphate, and carbonate-to-amide I band area ratios and the crystallinity index were quantified. SAXS/WAXS were used to study the nanostructure of mesiodens. An increase in the mineral content in the mesiodens dentin with respect to the normal group was found. Crystallinity was also significantly increased and the protein content decreased in the mesiodens dentin compared with that of normal dentin. SAXS/WAXS results revealed that mesiodens dentin has a more calcified tissue. Further, SAXS analysis revealed a nonuniform distribution of dentin fibrils in mesiodens.

Ab initio and density functional computations of the vibrational spectrum, molecular geometry and some molecular properties of the antidepressant drug sertraline (Zoloft) hydrochloride.

Sertraline hydrochloride is a highly potent and selective inhibitor of serotonin (5HT). It is a basic compound of pharmaceutical application for antidepressant treatment (brand name: Zoloft). Ab initio and density functional computations of the vibrational (IR) spectrum, the molecular geometry, the atomic charges and polarizabilities were carried out. The infrared spectrum of sertraline is recorded in the solid state. The observed IR wave numbers were analysed in light of the computed vibrational spectrum. On the basis of the comparison between calculated and experimental results and the comparison with related molecules, assignments of fundamental vibrational modes are examined. The X-ray geometry and experimental frequencies are compared with the results of our theoretical calculations.