Introducing 12 new dyes for use with oligonucleotide functionalised silver nanoparticles for DNA detection with SERS

Oligonucleotide functionalised metallic nanoparticles (MNPs) have been shown to be an effective tool in the detection of disease-specific DNA and have been employed in a number of diagnostic assays. The MNPs are also capable of facilitating surface enhanced Raman scattering (SERS) enabling detection to become highly sensitive. Herein we demonstrate the expansion of the range of specific SERS-active oligonucleotide MNPs through the use of 12 new Raman-active monomethine and trimethine chalcogenopyrylium and benzochalcogenopyrylium derivatives. This has resulted in an increased ability to carry out multiplexed analysis beyond the current small pool of resonant and non-resonant Raman active molecules, that have been used with oligonucleotide functionalised nanoparticles. Each dye examined here contains a variation of sulphur and selenium atoms in the heterocyclic core, together with phenyl, 2-thienyl, or 2-selenophenyl substituents on the 2,2’,6, and 6’ positions of the chalcogenopyrylium dyes and 2 and 2’ positions of the benzochalcogenopyrylium dyes. The intensity of SERS obtained from each dye upon conjugate hybridisation with a complementary single stranded piece of DNA was explored. Differing concentrations of each dye (1000, 3000, 5000 and 7000 equivalents per NP-DNA conjugate) were used to understand the effects of Raman reporter coating on the overall Raman intensity. It was discovered that dye concentration did not affect the target/control ratio, which remained relatively constant throughout and that a lower concentration of Raman reporter was favourable in order to avoid NP instability. A relationship between the dye structure and SERS intensity was discovered, leaving scope for future development of specific dyes containing substituents favourable for discrimination in a multiplex by SERS. Methine dyes containing S and Se in the backbone and at least 2 phenyls as substituents give the highest SERS signal following DNA-induced aggregation. Principal component analysis (PCA) was performed on the data to show differentiation between the dye classes and highlight possible future multiplexing capabilities of the 12 investigated dyes

PERILAKU DAN KARAKTERISTIK PENDERITA HIV- AIDS DI WILAYAH KERJA DINAS KESEHATAN KABUPATEN KEPULAUAN SANGIHE

Acquired Immune Deficiency Syndrome (AIDS) merupakan kumpulan gejala penyakit yang disebabkan oleh Virus HIV(Human Immunodeficiency Virus) yang mudah menular dan mematikan. Organisasi Kesehatan Sedunia (WHO) memperkirakan bahwa sekitar 15 juta orang diantaranya 14 juta remaja dan dewasa terinfeksi HIV, 1 juta bayi yang dilahirkanoleh ibu yang terinfeksi AIDS. Faktor Perilaku merupakan risiko penularan HIV tertinggi yaitu hubungan seks tidakaman pada heteroseksual (46,2%) penggunaan jarum suntik tidak steril pada Penasun (3,4%), dan lelaki sesama lelaki(LSL) 24,4%). Rumusan Masalah” BagaimanakahPerilaku dan Karakteristik Penderita HIV-AIDS di Wilayah KerjaDinas Kesehatan Kabupaten Kepulauan Sangihe”? Tujuan Penelitian yaitu; Untuk mengetahui Perilaku dan karakteristikPenderita HIV-AIDS di Wilayah Kerja Kabupaten Kepulauan Sangihe. Metode Penelitian yaitu deskritif dengan metodeserial kasus. Sampel penelitian yaitu semua responden yang bersedia diwawancarai dengan jumlah 11 orang. Data yangdiperoleh secara langsung saat melakukan kunjungan rumah pada responden HIV-AIDS, melalui hasil wawancara sertaobservasi/pengamatan populasi.HASIL PENELITIANPerilaku responden HIV-AIDS meliputi sering mengunjungitempat-tempat terlarang yaitu 1 orang (9,09%) pernah melakukan hubungan seksual tidak aman (gonta ganti pasangan)1 orang (9,09%), tidak tahu 3 orang (27,27%), pernah melakukan hubungan seksual dengan sesama jenis, tidak tahu 2orang (18,18%) pernah melakukan jarum suntik bersama-sama, tidak tahu 3 orang (27,27%). Pernah melakukan donor/transfusi darah ya 1 orang (9,09%), tidak tahu 1 orang (9,09%). serta responden yang pernah melakukan hubunganseksual dengan orang yang terinfeksi HIV-AIDS yaitu menjawab ya 2 orang (18,8%), dan tidak tahu 9 orang (81,82)

Elucidation of the bonding of a near infrared dye to hollow gold nanospheres : a chalcogen tripod

Infrared surface enhanced Raman scattering (SERS) is an attractive technique for the in situ detection of nanoprobes in biological samples due to the greater depth of penetration and reduced interference compared to SERS in the visible region. A key challenge is to understand the surface layer formed in suspension when a specific label is added to the SERS substrate in aqueous suspension. SERS taken at different wavelengths, theoretical calculations, and surface-selective sum frequency generation vibrational spectroscopy (SFG-VS) were used to define the surface orientation and manner of attachment of a new class of infrared SERS label with a thiopyrylium core and four pendant 2-selenophenyl rings. Hollow gold nanospheres (HGNs) were used as the enhancing substrate and two distinct types of SERS spectra were obtained. With excitation close to resonance with both the near infrared electronic transition in the label (max 826 nm) and the plasmon resonance maximum (690 nm), surface enhanced resonance Raman scattering (SERRS) was obtained. SERRS indicates that the major axis of the core is near to perpendicular to the surface plane and SFG-VS obtained from a dried gold film gave a similar orientation with the major axis at an angle 64°-85° from the surface plane. Longer excitation wavelengths give SERS with little or no molecular resonance contribution and new vibrations appeared with significant displacements between the thiopyrylium core and the pendant selenophene rings. Analysis using calculated spectra with one or two rings rotated indicates that two rings on one end are rotated towards the metal surface to give an arrangement of two selenium and one sulphur atoms directly facing the gold structure. The spectra, together with a space filled model, indicate that the molecule is strongly adsorbed to the surface through the selenium and sulphur atoms in an arrangement which will facilitate layer formation

Comparison between base metals and platinum group metals in nitrogen, M codoped TiO 2 (M= Fe, Cu, Pd, Os) for photocatalytic removal of an organic dye in water

The photocatalytic performance of a number of nonmetal and metal codoped TiO2 for the degradation of eosin yellow under simulated solar radiation was investigated. The synthesised materials were characterised by FTIR, Raman spectroscopy, XRD, DRUV-Vis, SEM, and TEM.The N, metal codoped TiO2 containing 0.5 wt.% of the metal consisted mainly of the anatase phase, with a particle size range of 15–28 nm. The particles were largely spherical and shifted the absorption edge well into the visible region. Band gap reduction was more pronounced for the N, PGM codoped TiO2 compared to N, base metal codoped samples. Codoping led to an enhancement in the photocatalytic activity of the materials for the degradation of eosin yellow. N, Pd codoped TiO2 was the most effective photocatalyst (99.9% dye removal) while N, Cu codoped TiO2 showed the least activity (25.5% removal). The mechanism for the photocatalytic enhancement was proposed on the basis of formation of an electron deficient Schottky barrier at the semiconductor-metal interface, which acts as an electron sink and thus retards electron-hole recombination. It was shown that the ability of the photocatalyst to degrade the dye depends on the nature and type of the metal dopant in the codoped TiO2 system