skip to main content


Search for: All records

Award ID contains: 1940716

Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

  1. 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. 
    more » « less
  2. DNA is strongly adsorbed on oxidized graphene surfaces in the presence of divalent cations. Here, we studied the effect of DNA adsorption on electrochemical charge transfer at few-layered, oxygen-functionalized graphene (GOx) electrodes. DNA adsorption on the inkjet-printed GOx electrodes caused amplified current response from ferro/ferricyanide redox probe at concentration range 1 aM–10 nM in differential pulse voltammetry. We studied a number of variables that may affect the current response of the interface: sequence type, conformation, concentration, length, and ionic strength. Later, we showed a proof-of-concept DNA biosensing application, which is free from chemical immobilization of the probe and sensitive at attomolar concentration regime. We propose that GOx electrodes promise a low-cost solution to fabricate a highly sensitive platform for label-free and chemisorption-free DNA biosensing. 
    more » « less
  3. null (Ed.)
  4. 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, the expansions of TNR sequences are responsible for almost 24 neurodegenerative and neuromuscular diseases because their unique structures disrupt cell functions. The biophysical studies of these sequences affect their electrophoretic mobility and spectroscopic signatures. Here, we demonstrate a novel strategy to characterize and discriminate the TNR sequences by monitoring their capillary flow in the absence of an external driving force using wax-on-plastic microchannels. The wax-on-plastic microfluidic system translates the sequence-directed flexibility of TNR into differential flow dynamics. Several variables were used to characterize sequences including concentration, single- vs. double-stranded samples, type of repeat sequence, length of the 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 as these factors directly affect the structural flexibility of TNR at the molecular level. An overall trend was observed as the higher flexibility in the TNR structure leads to lower capillary flow. After testing samples derived from relevant cells harboring expanded TNR sequences, it is concluded that this approach may transform into a reagent-free and pump-free biosensing platform to detect microsatellite expansion diseases. 
    more » « less
  5. Trinucleotide repeat (TNR) sequences widely exist in nature and their overgrowth is associated with two dozen neurodegenerative diseases in humans. These sequences have a unique helical flexibility, which affects their biophysical properties. A number of biophysical properties of these sequences have been studied in the past except their surface-tethered monolayers. To address the effect of sequence context and the associated helical flexibility on TNR monolayers, disease-relevant TNRs from three flexibility groups were surface-assembled on gold surfaces. The properties of the TNR films were studied, including charge transfer resistance ( R ct ) by electrochemical impedance spectroscopy (EIS), surface density by chronocoulometry (CC), surface topography by atomic force microscopy (AFM), and electrical conductivity by conducting atomic force microscopy (C-AFM). We found that the TNR film properties are characteristically sequence dependent rather than being dependent on their flexibility rank reported in the literature. The characteristic properties of TNR films studied here may be used for engineering label-free biosensors to detect neurological disorders and build DNA bioelectronics. 
    more » « less