Unique Bifunctional Nanotubes for Biological Applications

Life Sciences : Research Tools

Available for licensing


  • Donglei Fan , Mechanical Engineering
  • Xiaobin Xu , University of Texas at Austin

Background/unmet need

In biomedical diagnostic applications such as biosubstance detection, bioanalysis and image-contrast enhancement, extremely high optical sensitivity at the single-cell level is highly desirable. To make this capability possible, the combination of surface-enhanced optical/spectroscopic techniques and nano-maneuverability is required.

Bi-functional plasmonic-magnetic nanoparticles (PM-NP) are such unique hybrid nanomaterials made of both optical and magnetic components in a nanoscale architecture: the plasmonic property provide orders-of-magnitude enhancement to the optical/spectroscopic sensitivity, while the magnetic property enables nano-manipulation with a magnetic field.

However, currently available bi-functional PM-NP has been largely limited to quasi-zero-dimensional structures (0D), such as nanospheres and nanoshells. This 0D structure, while useful, lacks the directional maneuverability that comes with more sophisticated structures.

Invention Description

Researchers at UT Austin have invented a unique 1-D PM nanotube consisting of silica nanotubes with embedded nanomagnets and surface-coated plasmonic Ag nanoparticles. The nanotubes provide a large number of hot spots for surface-enhanced Raman scattering (SERS) with an enhancement factor(EF) of 3.8 x 1010, making it possible for reproducible and ultrasensitive molecular-level detection. The magnetic anisotropy of the nanotubes owing to the embedded nanomagnets can be tuned for high-efficiency nano-manipulation to desired positions, such as on the membrane of a single biological cell, for location-specific analysis.


  • Each nanotube can achieve a density of hot-spots up to 5000/µm2 for enhanced surface plasmonic effect with an EF of 3.8 x 1010.
  • Uniform plasmonic nanoparticles coated on the nanotube surface provide a variation of the SERS EF within 9%
  • Magnetic moment and anisotropy of the nanotubes can be facilely tuned.


  • The longitudinal geometry of the nanotubes can be designed to be compatible with both biological cells and biomolecules in terms of length and diameter.
  • By controlling the aspect ration of the embedded Ni nanosegment, the magnetic moment and anisotropy can be facilely tuned to desired value, which is important for efficient magnetic separation and manipulation.

Market potential/applications

Single-cell bioanalysis, biochemical detection, image-contrast enhancement, magnetic manipulation and separation, as well as biosubstance delivery.

Development Stage

Lab/bench prototype

IP Status

  • 1 U.S. patent application filed
  • 1 U.S. patent issued: 9,638,639