Surface Enhanced Spatially Offset Raman Spectroscopy Detection of Neurochemicals Through the Skull.

The ability to noninvasively detect neurotransmitters through the skull would aid in understanding brain function and the development of neurological diseases. Surface enhanced spatially offset Raman spectroscopy (SESORS) is a powerful technique that combines the sensitivity of surface-enhanced Raman spectroscopy (SERS) with the ability of spatially offset Raman spectroscopy (SORS) to probe subsurface layers. Here we present SERS measurements of neurotransmitters (melatonin, serotonin, and epinephrine) at various concentrations followed by the SESORS measurements of the neurotransmitters to a concentration as low as 100 µM in a brain tissue mimic through a cat skull. Principal components analysis was performed to distinguish between the surface bone layer and the subsurface layer, comprised of a brain tissue mimic modified with neurotransmitters, and to determine if each individual neurotransmitter could be accurately identified.

Copper complexes containing thiosemicarbazones derived from 6-nitropiperonal: Antimicrobial and biophysical properties.

A series of four thiosemicarbazones from 6-nitropiperonal along with the corresponding copper complexes were synthesized. The biophysical characteristics of the complexes were investigated by the binding to DNA and human serum albumin. The binding to DNA is moderate; the binding constants run from (0.49-7.50)×104M-1. In relation to HSA, the complexes interact strongly with binding constants on the order of 105M-1. The complexes also display antioxidant behavior as determined by the ability to scavenge diphenylpicrylhydrazyl (dpph) and nitric oxide radicals. The antimicrobial profiles of the compounds, tested against a panel of microbes including five of the ESKAPE pathogens (Staphylococcus aureus, MRSA, Escherichia coli, Klebsiella pneumoniae, MDR, Acinetobacter baumannii, Pseudomonas aeruginosa) and two yeasts (Candida albicans and Cryptococcus neoformans var. grubii), are also described. The compounds contain a core moiety that is similar to oxolinic acid, a quinolone antibiotic that targets DNA gyrase and topoisomerase (IV). The binding interaction between the complexes and these important antibacterial targets were studied by computational methods, chiefly docking studies. The calculated dissociation constants for the interaction with DNA gyrase B (from Staphylococcus aureus) range from 4.32 to 24.65µM; the binding was much stronger to topoisomerase IV, with dissociation constants ranging from 0.37 to 1.27µM.