(F-240) Highly integrated system for micro-total analysis of metal ions

Introduction:: Rapid and precision detection of metal ions in liquid-biopsy samples at the point of care holds great potential to advance biotechnology development and solve problems in healthcare and diagnosis. However, existing methods require complex pretreatment and large sample volume, or/and suffer from low precision and sensitivity. To overcome these limitations, we develop a highly integrated, miniaturized fluidic device that extracts sodium ions from milk (with an efficiency of >85%) and detect them at high sensitivity (~µM detection limit). Our result paves the way to efficacious point-of-care medical devices.


Materials and Methods:: We fabricate a highly integrated device that consists of a fluidic chip for sample preconditioning and a microfabricated metal-ion sensor. The fluidic chip contains a five-channel sandwich structure, two electrodes, and ion exchange membranes, to extract sodium ions from sample solution through electrodialysis in the transverse direction of the fluidic flow. The extracted metal ions are loaded onto the sensor for quantification. The sensor comprises an ion-selective field-effect transistor based on graphene monolayer functionalized with a sodium ion-sensitive ligand that bind to sodium ions selectively.


Results, Conclusions, and Discussions:: Results
Our research delivers a cm-size metal-ion total analysis device. Test of the device shows that sodium ions in a centrifuged milk sample can be isolated reliably at a high extraction efficiency of >85%. Using the metal-ion sensor, sodium ions can be detected with a wide dynamic range (10^-5-10^-1 M) and a high sensitivity of ~µM.

Conclusions

We developed a new lab-on-a-chip for quantifying the concentration of sodium ions in minimally processed milk. The device is highly integrated and miniaturized, functioning as both extractor and detector, with high extraction efficiency without compromise in sensitivity. Our result provides the potential of point-of-care total analysis of metal ions.

Discussions 
Our new, highly integrated, and miniaturized chip presents a promising approach to detecting metal-ion concentration in minimally treated complex biosamples. The methodology can be easily modified for detecting other metal ions beyond sodium, such as heavy metals include lead and mercury, and for other biofluidic samples, such as blood. The separation efficiency of the chip based on electrodialysis, along with the high sensitivity, suggest that this approach has significant potential for use in point-of-use clinical settings.


Acknowledgements (Optional): :

References (Optional): :