Fabrication of cost-effective analytical devices by wax printing has recently become popular using plastic based substrates e.g., polyethylene terephthalate (PET). Patterning of microfluidic devices on flexible substrate attracts the scientific community to explore applications in different aspects of health and point of care diagnostics. Flexible substrates offer unique characteristics such as flexibility, stretchability, portability, low-cost, and simple fabrication. We were able to pattern wax microchannels on PET substrate to develop microfluidics. In this presentation, I will talk about novel characterization strategy to discriminate TNR sequences by observing simple capillary flow of these sequences in wax-on-plastic microchannels without an external driving force. Trinucleotide repeat (TNR) sequences introduce sequence-directed flexibility in the genomic makeup of all living species leading to unique non-canonical structure formation. In humans, uncontrolled growth TNR sequences are responsible for almost twenty-four neurodegenerative and neuromuscular diseases because their unique structures disrupt cell functions. The biophysical signatures of these sequences are limited to electrophoretic mobility and spectroscopic signatures. The wax-on-plastic microfluidic system translates the sequence-directed flexibility of TNR sequences into differential flow dynamics. Several variables were used to characterize sequences including TNR sequence concentration, single- vs. double-stranded samples, type of repeat sequence, length of repeat sequence, presence of mismatches in duplex, and presence of metal ion. All these variables were found to influence the flow velocities of TNR sequences because these factors directly affect the structural flexibility of TNR sequences at molecular level. As a result, a trend was observed that higher flexibility in the TNR structure leads to lower flow velocity. After testing samples derived from cells, it is concluded that this approach may transform into a portable, reagent-free and pump-free biosensing platforms to detect neurodegenerative diseases.

Art of wax-printing on flexible plastics for microfluidic and biosensing application

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.