This communication reports that three prostate cancer cells of differing metastatic potential were discriminated based on their Young's moduli (LNCaP - 287 +/- 52 N m(-2), PC-3 - 1401 +/- 162 N m(-2) and BPH - 2797 +/- 491 N m(-2)) which were determined using AFM and the Hertz model.

An investigation into the use of Raman optical tweezers to study urological cell lines is reported, with the ultimate aim of determining the presence of malignant CaP cells in urine and peripheral fluids. To this end, we trapped and analyzed live CaP cells (PC-3) and bladder cells (MGH-U1), because both prostate and bladder cells are likely to be present in urine. The laser excitation wavelength of 514.5 nm was used, with Raman light collected both in back- and forward-scattering geometric configurations. For the backscattering configuration the same laser was used for trapping and excitation, while for forward scattering a 1064 nm laser provided the trapping beam. Analysis of cell-diameter distributions for cells analyzed suggested normal distribution of cell sizes, indicating an unbiased cell-selection criterion. Principal components analysis afforded discrimination of MGH-U1 and PC-3 spectra collected in either configuration, demonstrating that it is possible to trap, analyze, and differentiate PC-3 from MGH-U1 cells using a 514.5 nm laser. By loading plot analysis, possible biomolecules responsible for discrimination in both configurations were determined. Finally, the effect of cell size on discrimination was investigated, with results indicating that separation is based predominantly on cell type rather than cell size.

In this review the recent emergence of Raman tweezers as an analytical technique for single eukaryotic cell analysis is described. The Raman tweezer technique combines Raman spectroscopy as a diagnostic tool with optical tweezers by which means single cells can be trapped and manipulated in a laser beam using a high numerical aperture imaging microscope. Necessary instrumental requirements to facilitate Raman tweezer experiments are discussed together with practical considerations such as the potential for photodamage of cells subjected to trapping and Raman excitation. Specific applications of Raman tweezers to the analysis of cancer cells, erythrocytes and lymphocytes, micro-organisms and sub-cellular components e.g.chromosomes and mitochondria are then discussed followed by a summary of the future potential of the technique for single cell analysis.

In this paper we report on preliminary investigations into using Raman tweezers to classify urological cell lines. This builds on earlier work within the group, whereby Raman tweezer methodologies were developed, and the application of this technique to differentiate between live prostate cancer (CaP) and bladder cells lines (PC-3 and MGH-U1 respectively) was demonstrated.In this present study we analysed chemically fixed cells using two different fixative methods; SurePath (a commercial available liquid based cytology media) and 4% v/v formalin/PBS fixatives. The study has been expanded from our previous live cell study to include the androgen sensitive CaP cell line LNCaP, primary benign prostate hyperplasia (BPH) cells as well as primary urethral cells. Raman light from the cells was collected using a 514.5 nm Ar-ion laser excitation source in back-scattering configuration mode.Principal component-linear discriminate analysis (PC-LDA) models of resulting cell spectra were generated and these were validated using a blind comparison. Sensitivities and specificities of > 72% and 90% respectively, for SurePath fixed cells, and > 93% and 98% respectively for 4% v/v formalin/PBS fixed cells was achieved. The higher prediction results for the formalin fixed cells can be attributed to a better signal-to-noise ratio for spectra obtained from these cells.Following on from this work, urological cell lines were exposed to urine for up to 12 hours to determine the effect of urine on the ability to classify these cells. Results indicate that urine has no detrimental effect on prediction results.

In this communication reflection mode Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) is used to obtain IR spectra of four prostate and prostate cancer cell line types (CaP) allowing their differentiation by principal components analysis.