JOURNAL OF RAMAN SPECTROSCOPY J. Raman Spectrosc. 2008; 39: 1859–1868 Published online 15 August 2008 in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/jrs.2051 A study of the effect of JB particles on Saccharomyces cerevisiae (yeast) cells by Raman spectroscopy T. K. Bhowmick, 1 G. Pyrgiotakis, 2 K. Finton, 2 A. K. Suresh, 1 S. G. Kane, 1 B. Moudgil 2,3 and Jayesh R. Bellare 1* 1 Department of Chemical Engineering, and School of Biosciences and Bioengineering, IIT Bombay, India 2 Particle Engineering Research Center, University of Florida, USA 3 Department of Materials Science and Engineering, University of Florida, USA Received 11 December 2007; Accepted 21 May 2008 The mechanism of interaction of particulate matter with living system is not completely understood. Evaluation of the effect of particulate Indian traditional medicine JB(JB) on Saccharomyces cerevisiae (yeast) cells is the major focus of the present study. In India, JB is considered as a rejuvenating medicine and used for the treatment of diseases such as diabetes and age-related eye diseases, as well as a health promoting tonic by the traditional practitioners. In presence of JB, higher growth has been observed at the late stationary growth phase of yeast. Ultra-structure analysis using transmission electron microscopy (TEM) has shown that JB-treated yeast cells have better morphology over control in the late stationary growth phase. In this investigation, cellular response from yeast cells after interaction with JB particles was measured using Raman spectroscopy. Raman spectroscopy – a noninvasive tool to distinguish between particle-treated and untreated cells – revealed that treatment with JB is able to slow the degradation of cellular components (e.g. DNA, proteins and lipids) with the aging of yeast cells. Copyright  2008 John Wiley & Sons, Ltd. KEYWORDS: Raman spectroscopy; cell– particle interaction; yeast; freeze fracture; Bhasma INTRODUCTION Although particle – cell interactions have been shown to occur at many different levels and stages throughout history, it is only recently that this phenomenon has attracted a great deal of attention. This is due to its connection with terminal diseases such as silicosis, and more recently, to the health effects of nanostructured materials and particulates. Cellular response to particle interaction depends on several factors including particle composition and physical properties (e.g. surface area, crystal structure, hardness, zeta potential, size, shape), and cell type. 1–7 Current methods of studying such interactions, in vitro, include a large number of biological assays. However, limiting factors, such as cost and the inability of such assays to yield a comprehensive knowledge of the state of the cell, have led to the need for a more rapid and reliable method. In the current research approach, Raman spectroscopy, a vibrational spectroscopic technique, was explored to study particle–cell interactions. Raman spectroscopy is based on L Correspondence to: Jayesh R. Bellare, Department of Chemical Engineering, and School of Biosciences and Bioengineering, IIT Bombay-400 076 India. E-mail: jb@iitb.ac.in the inelastic scattering of photons from the molecules present in the biological system. This technique is able to measure the vibrational energies of the biomolecules quantitatively, thereby producing spectra that represent a chemical finger- print of the specimen. Although this technique has been used for several decades in studying biological samples, it is only recently that this technique is being used to study cell– particle interactions. A defining feature of Raman spec- troscopy is that samples can be analyzed in their natural environment, noninvasively, and in the case of living cells, without any significant injurious effects. Furthermore, com- pared to other spectroscopic techniques, the Raman signal from water is weak and, therefore, causes minimal interfer- ence during spectral analysis. In the past, various studies have utilized different spectroscopic techniques such as IR to investigate the effect of particles on biological systems; 8,9 however, Raman spectroscopy has gained attention only recently, basically due to the advances in the field by Hench et al., who found the appropriate wavelength that does not influences the cellular functions. In the current research, Raman spectroscopy was employed to investigate the effect of particles on cells. Effect of a traditional particulate medicine from India, namely Copyright  2008 John Wiley & Sons, Ltd.