Low frequency Raman spectroscopy is a highly sensitive and non-destructive technique used to investigate the vibrational and rotational modes of biological and non-biological materials. The Raman spectra measured provide information about the chemical structure and nature of these materials. In this study, we present the design and construction of a low frequency Raman spectroscopy system that is able to measure signals <10 cm-1 to <400 cm-1. The system consisted of a 514.5nm monochromatic laser directed through a polarizing beam cube and half waveplate to adjust the intensity of the beam. The beam was expanded and reflected off a 514.5 nm high pass filter before passing through a 50x Mitutoyo objective, which focuses it onto the sample. The back scattered light was recollimated through the objective. The high pass filter and three 514.5 nm Bragg filters were used to reduce the Rayleigh signal. The remaining Raman signal was focused into a Shamrock 303i spectrometer with a cooled ANDOR CCD camera. Using high dynamic range data acquisition with background subtraction, this system allowed low frequency Raman spectroscopy of reduced cytochrome C, bovine serum albumin, microtubules and collagen in solution. The system has the advantage of enabling the measurement of the low frequency Raman signal without sacrificing the ability to perform traditional Raman spectroscopy.
Raman and Brillouin spectroscopy are powerful tools for non-invasive and non-destructive investigations of material chemical and mechanical properties. In this study, we use a newly developed custom-built dual Raman-Brillouin microspectroscopy instrument to build on previous works studying in-vivo stress response of live plants using only a Raman spectroscopy system. This dual Raman-Brillouin spectroscopy system is capable of fast simultaneous spectra acquisition from single-point locations. Shifts and changes in a samples Brillouin spectrum indicate a change in the physical characteristics of the sample, namely mechano-elasticity; in measuring this change, we can establish a relationship between the mechanical properties of a sample and known stress response agents, such as reactive oxygen species and other chemical constituents as indicated by peaks in the Raman spectra of the same acquisition point. Simultaneous application of these spectroscopic techniques offers great promise for future development and applications in agricultural and biological studies and can help to improve our understanding of mechanochemical changes of plants and other biological samples in response to environmental and chemically induced stresses at microscopic or cellular level.
Recent developments in understanding of nanomaterial behaviors and synthesis have led to their application across a wide range of commercial and scientific applications. Recent investigations span from applications in nanomedicine and the development of novel drug delivery systems to nanoelectronics and biosensors. In this study, we propose the application of a newly engineered temperature sensitive water-based bio-compatible core/shell up-conversion nanoparticle (UCNP) in the development of a smart substrate for remote temperature sensing. We developed this smart substrate by dispersing functionalized nanoparticles into a polymer solution and then spin-coating the solution onto one side of a microscope slide to form a thin film substrate layer of evenly dispersed nanoparticles. By using spin-coating to deposit the particle solution we both create a uniform surface for the substrate while simultaneously avoid undesired particle agglomeration. Through this investigation, we have determined the sensitivity and capabilities of this smart substrate and conclude that further development can lead to a greater range of applications for this type smart substrate and use in remote temperature sensing in conjunction with other microscopy and spectroscopy investigations.