Research

Biosensing and Diagnostics

Sensitive, reliable, and low-cost diagnostics are urgently needed for diagnosing diseases and detecting pollution, especially in resource-limited settings. Ideally, such diagnostics should also be simple and easy to use. We are committed to addressing challenge issues of current diagnostic techniques by taking advantage of the unique properties of nanomaterials (e.g., plasmonic and catalytic activities). For example, we are engineering bimetallic nanostructures as peroxidase mimics for colorimetric assays. Compared to their natural counterparts, these mimics are more sensitive and stable, providing highly sensitive and reliable diagnosis. In another example, we are developing point-of-care diagnostics with enhanced detection sensitivity and specificity by utilizing metallic nanocrystals. Our ultimate goal is to solve key healthcare problems with our technological innovations.

Selected publications in this area:

  1. Gao, Z.; Ye, H.; Tang, D.; Tao, J.; Habibi, S.; Minerick, A.; Tang, D.; Xia, X. Platinum decorated gold nanoparticles with dual functionalities for ultrasensitive colorimetric in vitro diagnostics. Nano Letters, 2017, 17, 5572–5579.
  2. Li, J.; Gao, Z.; Ye, H.; Wan, S.; Pierce, M.; Tang, D.; Xia, X. A non-enzyme cascade amplification strategy for colorimetric assay of disease biomarkers. Chemical Communications, 2017, 53, 9055–9058.
  3. Ye, H.; Yang, K.; Tao, J.; Liu, Y.; Zhang, Q.; Habibi, S.; Nie, Z.; Xia, X. An Enzyme-free signal amplification technique for ultrasensitive colorimetric assay of disease biomarkers. ACS Nano, 2017, 11, 2052-2059.
  4. Gao, Z.; Liu, G.G.; Ye, H.; Rauschendorfer, R.; Tang, D.; Xia, X. Facile colorimetric detection of silver ions with picomolar sensitivity. Analytical Chemistry, 2017, 89, 3622-3629.
  5. Xia, X.; Zhang, J.; Lu, N.; Kim, M.; Ghale, K.; Xu, Y.; McKenzie, E.; Liu, J.; Ye, H. Pd-Ir core-shell nanocubes: A type of highly efficient and versatile peroxidase mimic. ACS Nano 2015, 9, 9994-10004.
  6. Xia, X.; Xu, Y.; Ke, R.; Zhang, H.; Yang, W.; Zou, M.; Li, Q. A highly sensitive europium nanoparticle-based lateral flow immunoassay for detection of chloramphenicol residue. Analytical and Bioanalytical Chemistry 2013, 405, 7541-7544.

Design and Synthesis of Functional Nanomaterials

The properties and performance of nanomaterials have a strong dependence on their size, shape, and chemical composition. By carefully manipulating the thermodynamic and/or kinetic parameters during a synthesis, we aim to design and synthesize colloidal nanocrystals with specific morphologies and compositions sought for a variety of fundamental studies and technologically important applications. By taking advantage of modern high-resolution electron microscopy, we are interested in monitoring nanocrystal growth and characterizing final products at the atomic level, and gaining deep insight into the structure-property relationship. The nanomaterials we are currently exploring include noble-metal (e.g., Au, Ag, Pd, Pt, Ir, and Ru), magnetic, silica, and metal-based hybrid nanomaterials.

Selected publications in this area:

  1. Wan, S.; Wang, Q.; Ye, H.; Kim, M. J.; Xia, X. Pd–Ru bimetallic nanocrystals with a porous structure and their enhanced catalytic properties. Part. Part. Syst. Charact., 2018, DOI 10.1002/ppsc.201700386.
  2. Ye, H.; Liu, Y.; Chhabra, A.; Lilla, E.; Xia, X. Polyvinylpyrrolidone (PVP)-capped Pt nanocubes with superior peroxidase-like activity. ChemNanoMat, 2017, 3, 33–38.
  3. Ye, H.; Wang, Q.; Catalano, M.; Lu, N.; Vermeylen, J.; Kim, M.; Liu, Y.; Sun, Y.; Xia, X. Ru nanoframes with an fcc structure and enhanced catalytic properties. Nano Letters 2016, 16, 2812-2817.
  4. Xia, Y.; Xia, X.; Peng, H.-C. Shape-controlled synthesis of colloidal metal nanocrystals: thermodynamic versus kinetic products. Journal of the American Chemical Society 2015, 137, 7947-7966.
  5. Xia, X.; Figueroa-Cosme, L.; Tao, J.; Peng, H.-C.; Niu, G.; Zhu, Y.; Xia, Y. Facile synthesis of iridium nanocrystals with well-controlled facets using seed-mediated growth. Journal of the American Chemical Society 2014, 136, 10878-10881.
  6. Xia, X.; Xie, S.; Liu, M.; Peng, H.-C.; Lu, N.; Wang, J.; Kim, M. J.; Xia, Y. On the role of surface diffusion in determining the shape or morphology of noble-metal nanocrystals. Proceedings of the National Academy of Sciences USA 2013, 110, 6669-6673.

Effective and Sustainable Usage of Nanomaterials

To effectively use functional nanomaterials in certain applications, we enhance their performance by modifying their surfaces with unique chemical ligands, biomolecules, shells, and secondary functional nanoparticles. We investigate the roles played by surface chemistry in determining the properties of nanocrystals and the fundamental crystal growth process during synthesis. We are also interested in developing strategies for recycling and re-using high-cost materials to achieve a sustainable usage of precious materials. The ultimate goal is to produce highly active, sustainable, and safe nanomaterials suitable for important applications such as biomedicine and catalysis.

Selected publications in this area:

  1. Wang, Y.; Liu, Y.; Luehman, H.; Xia, X.; Wan, D.; Cutler, C.; Xia, Y.Radioluminescent Au nanocages with controlled radioactivity for real-time multimodality imaging. Nano Letters 2013, 13, 581-585.
  2. Xia, X.; Zeng, J.; Otejen, L. K.; Li, Q.; Xia, Y. Quantitative analysis of the role played by poly(vinylpyrrolidone) in seed-mediated growth of silver nanocrystals. Journal of the American Chemical Society 2012, 134, 1793-1801.
  3. Xia, X.; Li, W.; Zhang, Y.; Xia, Y. Silica-coated dimers of silver nanospheres as SERS tags for imaging cancer cells. Interface Focus 2013, 3, 20120092.
  4. Xia, X.; Yang, M.; Wang, Y.; Zheng, Y.; Li, Q.; Chen, J.; Xia, Y. Quantifying the coverage density of poly(ethylene glycol) chains on the surface of gold nanostructures. ACS Nano 2012, 6, 512-522.
  5. Xia, X.; Xu, Y.; Zhao, X.; Li, Q. Lateral flow immunoassay using europium chelate loaded silica nanoparticles as labels. Clinical Chemistry2009, 55, 179-182.