LONDON STMicroelectronics has demonstrated a prototype device capable of selectively collecting and manipulating biological molecules which the chip group suggests opens the way to cost-effective automated sample preparation for medical and forensic diagnostics.
The system was built using a technology compatible with the MEMS technology that ST uses for its In-Check lab-on-chip devices.
The prototype chip contains a tiny channel, measuring about 1mm in length, 0.1mm in width and 50 microns in height which is filled with a solution containing the molecules of interest. On the bottom of the channel, an array of tiny platinum electrodes (25micron wide, separated by 25 microns) provides precise control over the pattern of the electric field in the channel and therefore the forces applied to the biological molecules.
ST says current biotechnological platforms such as its In-Check devices, work for the diagnosis of specific diseases or the monitoring of food and water for bacterial contaminants by allowing the rapid detection of particular genetic material in liquid biological samples. But the preparation of the samples is still a relatively time-consuming process performed with large samples in laboratories using techniques that require skilled technicians and are difficult and expensive to implement with smaller samples.
It adds the aim of its research program is to explore new methods to automate sample preparation, so that the biological molecules of interest could be rapidly extracted from "raw" specimens such as saliva, blood or biopsy tissues and used as the input to the lab-on-chip diagnostic stage.
"The market for diagnostic equipment is evolving towards fully automated, cost-effective devices usable directly at the point of need," said Maria Teresa Gatti, Director of Research and Innovation, Advanced System Technology, STMicroelectronics.
Details of the research project were unveiled at this week's NANOMEC06 Symposium on Materials Science & Materials Mechanics at the Nanoscale, held at the Politecnico di Bari, Italy in a paper presented by Marco Bianchessi, Sarah Burgarella and Anna Zocco from ST’s Advanced Systems Technology (AST) organization.
The project builds on a prior joint research project between ST and Evotec Technologies GmbH.
The technique used by the ST researchers is based on dielectrophoresis, where an electric field is used to separate biological particles contained in a conductive solution. The careful setting of physical and electrical factors allows precise control of the movement of target particles and researchers demonstrated that this could be exploited for practical uses.
Potential benefits include the ability to isolate cells that are present in low concentrations, to increase the concentration of cells in a solution and to extract DNA from the cell nucleus, as well as allowing sample preparation to be performed in the field by personnel with minimal training on the use of the devices.
Importantly, the researchers also successfully showed that by precisely controlling the voltage applied to different electrodes, cells could be collected at one specific region and then moved to other regions in either direction.
"Sample preparation technology, integrated with ST’s In-Check lab-on-chip platform, will allow us to build low-cost, easy-to-use systems that will enable diagnostic analyses to be performed outside specialized laboratories, e.g. directly in hospitals or even in the doctor’s office," noted Anton Hofmeister, Group VP and General Manager, Microfluidics Division, STMicroelectronics.