Novel Cancer Detection Method Uses Tiny Silica Beads To Adhere To Cells

The group's paper is published in Small.

Methods for detection of cancer cells are mostly based on traditional techniques used in biology, such as visual identification of malignant changes, cell-growth analysis or genetic tests.

Despite being well developed, these methods are either insufficiently accurate or require a lengthy complicated analysis, which is impractical for clinical use.

Sokolov and his team hope that the physical sciences can help to develop an alternative method in the detection of cancer cells, which will be more precise and simpler.

His group reports in Small on a method to detect cancer cells by using nonspecific (just physical) adhesion of silica beads to cells.

This finding is based on their recently published results in Nature Nanotechnology, where they reported on observation of unknown before difference in surface physical properties of cancerous and normal human epithelial cervical cells. Specifically, they found a substantial difference in the brush layer on the cell surface. This difference was the main motivation for their present work. The difference in the brush was expected to lead to the differences in the adhesion of various particles to such cells.

The adhesion was studied with the help of atomic force microscopy (AFM). Silica beads were attached to the AFM cantilever, and consequently, touched the cell surfaces. The force needed to separate the bead from the cell, the adhesion force, was measured.

The difference in adhesion, which has an essentially physical nature, was used to distinguish between cancerous and normal cells. High adhesion resulted in more particles adhered to cells. Utilizing fluorescent silica particle, one can easily measure the amount of fluorescent light coming from such cells.

The researchers used ultrabright fluorescent silica particles − the brightest particles ever synthesized -- also developed by Sokolov's team. Using cells collected from cervical cancers of three cancer patients and cells extracted from tissue of healthy patients, the researchers found an unambiguous difference.

This achievement can lead to earlier detection and treatment of cancer, which is important to decrease fatality of this disease considerably.

While this finding might advance to novel methods in diagnosis and treatment, including improved speed, convenience and accuracy, Sokolov says "The problem is in the variability of human subjects. The difference was found for six human subjects. This might be enough for a demonstration, but it is not sufficient to speak about a new clinical method. More statistics must be collected before we can speak about clinical applications." As the team prepares a more detailed summary of results, he and Biology Professor Craig Woodworth are writing a proposal for further study to the National Institutes of Health.

The team consists of Sokolov, who has appointments in Physics, Chemistry and Biomolecular Science; Woodworth, a cervical cancer expert; Maxim Dokukin, a physics postdoctoral fellow; and Ravi M. Gaikwad and Nataliaa Guz, physics graduate students. The other members of Sokolov's group, Eun-Bum Cho (physics postdoctoral fellow), and physics graduate students Dmytro Volkov and Shyuzhene Li, work on biosensors, self-assembly of particles, and the study of skin aging.