Microchip Development for Extracellular Vesicle Capture and Disruption for Cancer Diagnosis

Early detection of a disease is a crucial element for the effectiveness of the underlying treatment. Cancer is a prominent example of a disease whose early detection allows for an exponential increase of cancer survivors. Hence, it is essential to enhance the probability of detecting cancerous cells or masses with a testing device that is easy, reliable, portable, cheap, and efficient.
Recently, it was found that most types of cancerous cells shed large numbers of extracellular vesicles (EVs), that carry the molecular information of the parent tumour. Moreover, says materials science expert Dr Ryo Ishihara, these EVs have been found to circulate through many different body fluids within the human body such as blood and urine. Therefore, the development of testing devices that can detect and disrupt these membranous structures can be a useful clinical and research tool for early cancer detection, which is the primary objective of the latest research project he is undertaking in partnership with Dr Tadaaki Nakajima. 'Combining information from surface and inside of extracellular vesicles (EVs) utilising a surface-functionalised power-free microchip would provide reliable disease diagnosis, including a first cancer point-of-care diagnosis,' highlights Ishihara.
The focus of their work is the development of a portable surface-functionalised power-free PDMS microfluidic chip (SF-PF microchip). The key to this device is that it utilises information stemming from both the surface and the inside of the EVs. This microchip is based on two distinct processes: EV detection and EV disruption. 'For EV detection, we developed a polydimethylsiloxane microfluidic chip whose microchannels' are functionalised by UV grafting,' explains Nakajima. However, and for capturing cancer-specific EVs, the team needed to select appropriate antibodies. 'To select the antibody for cancer-specific EV capture, first we tried to compare the protein between mammary gland epithelial cell and breast cancer cell,' he continues. 'So, we re-analysed the proteome analysis data and we decided that integrin should be the target antigen.'
On the other hand, and for EV disruption, the team utilises quaternary ammonium ion immobilised-polymer chain-grafted surface that does not require the use of surfactants. 'The SF-PF microchip might be the first portable EV analysis (surface and inside) device,' outlines Ishihara. 'It enables EV separation, condensation, purification, and analysis because of the surface-partially-functionalised microfluidic chip. Furthermore, the SF-PF microchip might provide reliable point-of-care diagnosis of various diseases, including a first cancer point-of-care diagnosis.'