skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.


Search for: All records

Creators/Authors contains: "Wang, Danling"

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. Pancreatic cancer is increasingly prevalent and characterized by a high mortality rate. Due to the limitations of current diagnostic methods, early-stage detection remains elusive, contributing to persistently low survival rates among affected individuals. Nanomaterials have garnered significant attention in cancer research for their potential diagnostic applications. Among these, MXenes – a novel family of two-dimensional nanomaterials composed of transition metal carbides, nitrides, and carbonitrides – are of particular interest due to their unique properties. These include high electrical conductivity, hydrophilicity, thermal stability, large interlayer spacing, tunable structure, and high surface area. These characteristics make MXenes highly effective for detecting trace amounts of various analytes. In addition, their tunable structure enables precise manipulation of their properties, allowing for optimized sensing responses. Montmorillonite nanoclay (MMT), a member of the smectite group of natural clay minerals, is known for its ability to promote bone development and influence cell behavior. When combined with MXenes, MMT forms promising nanocomposites for early pancreatic cancer detection through sensing applications. The Ti3C2 MXene-MMT nanocomposites exhibit potential as scaffold sensors capable of distinguishing cancerous from non-cancerous samples by observing the distinctive patterns in resistance changes. In addition, MXenes possess excellent selectivity, allowing for the reliable identification of targeted analytes from a complex mixture of chemical and biological analytes. Due to the advanced sensing capabilities of MXene-MMT composite scaffold sensors, they hold great promise for early cancer diagnosis and tissue regeneration, providing a novel therapeutic approach to improving patient outcomes. 
    more » « less
  2. This study provides new insights into the development of high-performance MXene-reinforced coatings to strengthen polymeric nanocomposites by enhancing microstructure, anti-aging properties, corrosion resistance, and robustness. MXene nanoparticles, labeled 25C and 80C, were synthesized using two different methods and incorporated at concentrations ranging from 0.1 to 2.0 wt.% into epoxy composites. The results demonstrated that 80C MXene, characterized by its finer morphology and superior dispersion, significantly improved the composite's performance compared to 25C. Electrochemical Impedance Spectroscopy (EIS) tests, along with long-term exposure assessments, suggested that incorporating both types of MXene nanoparticles enhances the corrosion protection performance of epoxy coatings over time. Micro-CT analysis revealed that both types of MXene substantially reduced defects and voids in the polymeric matrix, resulting in enhanced protective performance. This void reduction confirms that the incorporation of both 25C and 80C MXene improves microstructural integrity by filling voids and creating a more continuous, uniform structure, particularly in samples with 0.1% to 1.0% MXene flakes. The findings also highlighted MXene's potential in modifying the anti-aging properties of epoxy by inhibiting free radical generation and enhancing the composite's resistance against corrosion. Both 25C and 80C MXene-epoxy groups exhibited a clear trend of diminishing free radical intensity with increasing MXene concentration up to 1.0%, with free radical intensity reduced by over 40% compared to neat epoxy. The relationship between MXene concentration and reinforcement was also investigated, revealing superior corrosion protection properties at concentrations of 0.5-1.0 wt.%. This research offers a profound understanding of MXene's potential in polymer-based composites, laying a foundation for future investigations aimed at utilizing MXene to achieve superior material properties for a wide range of applications, particularly in the realm of metallic surface protection. 
    more » « less
  3. This study explored the enhancement potential of MXene, a novel two-dimensional material, in epoxy-based nanocomposites; which comprehensively examined the influence of MXene on epoxy's viscosity, void formation, aging resistance, mechanical properties, and anti-wear properties. MXene nanofillers, labeled as 25C and 80C, fabricated via different acid-etching methods, were incorporated into epoxy resin at varying weight percentages (0.1-2.0 wt.%). Observations revealed that for both varieties of MXene, inclusion of 1.0 wt.% MXene led to the mitigation of void content, whereas the incorporation of 2.0 wt.% MXene yielded maximal enhancements in both tensile strength and abrasion resistance. Additionally, the integration of 1.0 and 2.0 wt.% MXene displayed superior aging resistance, with around 80% reduction in free radical formation compared to the unmodified epoxy, while maintaining its excellent mechanical properties after QUV exposure. Therefore, both MXene types significantly enhanced the performance of epoxy composites, with the 80C-MXene displaying marginally superior enhancement due to its smaller particle size and higher purity, as identified by SEM and TEM images. 
    more » « less
  4. Studies of optical properties of doped nanocrystals of tungsten trioxide can elucidate new information about the material. A novel molecule-enhanced photoluminescence (PL) of potassium-doped tungsten trioxide (K x WO) was explored in the presence of different gases to understand charge transfer between molecules and K x WO on the properties of the material. We performed Raman spectroscopy and PL experiments in the presence of gaseous acetone or ethanol mixed with other gases (N 2 and O 2 ). PL at 630 nm from K x WO was observed and further enhanced when the sample was continuously irradiated with a 532 nm CW laser in acetone. A mechanism of strong emission of the PL induced by the charge transfer between the acetone and the K x WO is proposed. 
    more » « less
  5. The rates of diabetes throughout the world are rising rapidly, impacting nearly every country. New research is focused on better ways to monitor and treat this disease. Breath acetone levels have been defined as a biomarker for diabetes. The development of a method to monitor and diagnose diabetes utilizing breath acetone levels would provide a fast, easy, and non-invasive treatment option. An ideal material for point-of-care diabetes management would need to have a high response to acetone, high acetone selectivity, low interference from humidity, and be able to operate at room temperature. Chemiresistive gas sensors are a promising method for sensing breath acetone due to their simple fabrication and easy operation. Certain semiconductor materials in chemiresistive sensors can react to acetone in the air and produce changes in resistance that can be correlated with acetone levels. While these materials have been developed and show strong responses to acetone with good selectivity, most of them must operate at high temperatures (compared to RT), causing high power consumption, unstable device operation, and complex device design. In this paper, we systematically studied a series of 2-dimensional MXene-based nanocomposites as the sensing materials in chemiresistive sensors to detect 2.86 ppm of acetone at room temperature. Most of them showed great sensitivity and selectivity for acetone. In particular, the 1D/2D CrWO/Ti3C2 nanocomposite showed the best sensing response to acetone: nine times higher sensitivity than 1D KWO nanowires. To determine the sensing selectivity, a CrWO/Ti3C2 nanocomposite-based sensor was exposed to various common vapors in human breath. The result revealed that it has excellent selectivity for acetone, and far lower responses to other vapors. All these preliminary results indicate that this material is a promising candidate for the creation of a point-of-care diabetes management device. 
    more » « less