Microfluidics & Optical Nanodevices

It is well known that individual cells, even those identical in appearance, differ in numerous characteristics. Due to this heterogeneity, traditional biochemical assays which analyse cells in bulk do not allow to get rich information available when single cells are studied. Conventional analysis of biological samples involves slow, expensive chromatographic and spectroscopic techniques which are not sensitive enough for the analysis of few target molecules. Single-cell analysis allows to study drug stimulation and to distinguish the diversity of the individual cell activities, and potentially to investigate new biomarkers.
It becomes then important for scientific research and clinical diagnostic applications, a sequential handling and manipulation of cells and cell suspensions. We developed microfluidic devices can ensure accurate single cell handling by simple microfluidic control with minimal consumption of reagents (see picture below).



Another critical issue is to individuate a sensing methodology which allows to reach a resolution at single cell level. Monitoring of cells to over a longer period of time is most frequently performed by fluorescence microscopy. However, it is quite common that the fluorescent dyes used for specific subcellular staining interfere with the development of cells, changing their phenotype and metabolism. The hydrophobicity of fluorescent stains may also cause them to adhere to glass or polymers, which are used for the fabrication of the microbioreactors. Another limitation is that fluorescent dyes bleach quite fast. Finally, this technique allows to investigate known molecules only. These aspects make fluorescence staining strategies less desirable in respect to label free sensing methodologies, luke using plasmonic sensors.

Our purpose is to develop microfluidic devices integrating microfluidic traps able to handle single cells and nanodevices which have a high potential for the analysis of living cells (see picture below).



Raman spectroscopy on cells can be used to determine cellular status, such as living cells, dead cells, poptotic cells, proliferating cells, and differentiating cells. In recent studies, Raman spectroscopy has been integrated in microfluidic environment to analyse cells over a long period of time.
 
REFERENCES

1) G. Perozziello, "Innovative Bioanalytical Tools Combining Microfluidics and Plasmonics for Cell Screening Purposes" J Bioanal Tech, 2016, 1(1): doi http://dx.doi.org/10.16966/jbt.e101 (Editorial);  

2) G. Perozziello, P. Candeloro, A. De Grazia, F. Esposito, M. Allione, M. L. Coluccio, R. Tallerico, I. Valpapuram, L. Tirinato, G. Das, A. Giugni, B. Torre, P. Veltri, U. Kruhne, G. Della Valle, and E. Di Fabrizio, "Microfluidic device for continuous single cells analysis via Raman spectroscopy enhanced by integrated plasmonic nanodimers", Optics Express, 2016, 24(2), A180-A190;
 
3) G. Perozziello, R. Catalano, M. Francardi, E. Rondanina, F. Pardeo, F. De Angelis,  N. Malara, P. Candeloro, G. Morrone, E. Di Fabrizio "A microfluidic device integrating plasmonic nanodevices for Raman spectroscopy analysis on trapped single living cells" accepted to Microelectronic engineering (2013), http://dx.doi.org/10.1016/j.mee.2013.02.023 .

4)
Liberale C, Cojoc G, Bragheri F, Minzioni P, Perozziello G, La Rocca R, Ferrara L, Rajamanickam V, Di Fabrizio E, Cristiani I, Integrated microfluidic device for single-cell trapping and spectroscopy. SCIENTIFIC REPORTS, vol. 3, 1258, ISSN: 2045-2322, (2013) doi: 10.1038/srep01258.