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We present a PNA microprobe sensing platform to detect trinucleotide repeat mutation by electrochemical impedance spectroscopy. The microprobe platform discriminated Huntington's disease-associated CAG repeats in cell-derived total RNA with S/N 1 : 3. This sensitive, label-free, and PCR-free detection strategy may be employed in the future to develop biosensing platforms for the detection of a plethora of repeat expansion disorders.

DNA interfaces with nano, micro, and macro materials have gained widespread attention for various applications. Such interfaces exhibit distinct functions and properties not only due to the unique properties of interfacing materials but also sequence- and conformation-dependent characteristics of the DNA. Therefore, DNA interfaces with diverse dimensional materials have advanced our understanding of the interaction mechanisms and the properties of such interfaces. The unique interfacial properties of such novel materials have applications in nanotechnology, biophysics, cell biology, biosensing, and bioelectronics. The field is growing rapidly with the frequent emergence of new interfaces carrying remarkable interfacial character. In this review article, we have classified the DNA interfaces into 0D, 1D, 2D, and 3D categories based on the types of dimensional materials. We review the key efforts made in the last five years and focus on types of interfaces, interfacing mechanisms, and their state-of-the-art applications. This review will draw a general interest because of the diversity in the DNA materials science but also the unique applications that will play a cutting-edge role in biomedical and biosensing research.

The fabrication of cost effective paper-based analytical devices by wax printing has recently become popular, by and large, using cellulose filter papers. Paper-based devices need higher temperature to form hydrophobic barrier across paper substrate, rely on large working channels (≥500 μm) for liquid handling, and exhibit lower efficiency (∼50%) of sample mobility. Such limitations confine applications of wax based fabrication. In this work, we report printability, fidelity, and application of wax micropatterns on a non-cellulosic, non-fibrous, and non-porous polyethylene terephthalate based substrate (mPET). Resolution of wax printing on mPET was found to be 120 μm for line and 60 μm for channel micropatterns. The wax micropatterns can sustain heat and retain their structural integrity at melting temperature of wax and above (≥120 °C). In application, wax microwells were patterned on the new substrate in a high throughput fashion, which formed a suitable niche for mouse embryonic stem cell (mESC) culture either to maintain self-renewal or direct differentiation. This study will open a new direction in wax printing applications not only as a low-cost but a multipurpose fabrication tool.