While the basis of neuronal degeneration in Alzheimer's disease (AD) continues to be debated, the amyloid cascade hypothesis remains central. Amyloid plaques are a required pathological marker for post mortem diagnosis, and Aβ peptide is regarded by most as a critical trigger at the very least. We present spectrochemical image analysis of brain tissue sections obtained with the mid-infrared beamline IRENI (InfraRed ENvironmental Imaging, Synchrotron Radiation Center, U Wisconsin-Madison), where the pixel resolution of 0.54 × 0.54 µm(2) permits analysis at sub-cellular dimensions. Spectrochemical images of dense core plaque found in hippocampus and cortex sections of two transgenic mouse models of AD (TgCRND8 and 3×Tg) are compared with plaque images from a 91 year old apoE43 human AD case. Spectral analysis was done in conjunction with histochemical stains of serial sections. A lipid membrane-like spectral signature surrounded and infiltrated the dense core plaques in all cases. Remarkable compositional similarities in early stage plaques suggest similar routes to plaque formation, regardless of genetic predisposition or mammalian origin.

We report Fourier transform infrared spectro-microtomography, a nondestructive three-dimensional imaging approach that reveals the distribution of distinctive chemical compositions throughout an intact biological or materials sample. The method combines mid-infrared absorption contrast with computed tomographic data acquisition and reconstruction to enhance chemical and morphological localization by determining a complete infrared spectrum for every voxel (millions of spectra determined per sample).

3-Methoxy-17α-ethynylestradiol or mestranol is a prodrug for ethynylestradiol and the estrogen component of some oral contraceptive formulations. We demonstrate here that a single core multimodal probe for imaging - SCoMPI - can be efficiently grafted onto mestranol allowing its tracking in two breast cancer cell lines, MDA-MB-231 and MCF-7 fixed cells. Correlative imaging studies based on luminescence (synchrotron UV spectromicroscopy, wide field and confocal fluorescence microscopies) and vibrational (AFMIR, synchrotron FTIR spectromicroscopy, synchrotron-based multiple beam FTIR imaging, confocal Raman microspectroscopy) spectroscopies were consistent with one another and showed a Golgi apparatus distribution of the SCoMPI-mestranol conjugate in both cell lines.

Sensors based on graphene and functionalized graphene are emerging as the state of the art for detecting extremely small quantities of target molecules under realistic working conditions with high selectivity. Although some theoretical work has emerged to understand such adsorption processes ( Tang Cao J. Phys. Chem. C20121168778; Leenaerts Phys. Rev. B200877125416; Tang Cao J. Chem. Phys.2011134044710), little experimental evidence detailing the dynamics of the adsorption and resulting surface species has been reported. Here, we study the adsorption of NH3 on reduced graphene oxide (RGO) using in situ infrared (IR) microspectroscopy performed under realistic working conditions (i.e., ambient pressure), along with density functional theory (DFT) calculations to support experimental observations. Conclusions drawn from experiment and theory reveal the presence of various surface species that impact the conductivity of the substrate at varying rates. The species arising from adsorption and interactions between NH3 and RGO include molecularly physisorbed NH3, as well as chemisorbed fragments such as NH2, OH, and CH due to dissociation of NH3 at defects and epoxide groups.