A new technique for direct writing of arbitrary 3D micro-hollow structures

The use of ANFF-Q’s Nanoscribe has enabled Caizhi Liao, a University of Queensland PhD student, to create a series of elegantly designed micro-hollow structures, including the volcanic-shape micro-pore, micro-needle, micro-valve, micro-electrode and micro-robot.

Volcanic-shape micro-pore structure for resistive-pulse sensing; micro-needle structure for drug/vaccine delivery; micro-valve for controlling the fluids in bio-systems; micro-electrodes for simultaneous recording and stimulation of cells; micro-robots for clinical and medical applications. Credit to: Caizhi Liao & Will Anderson.

Caizhi’s structures provide new possibilities for the creation of precise micro-structures of interest in a variety of biological fields, such as bio-sensing, drug and vaccine delivery, bio-fluids control, medical applications, and even the simultaneous recording and stimulation of cells.

This brand-new fabrication scheme using the Nanoscribe enables the creation of micro-hollow structures which cannot be obtained using conventional nano/micro-fabrication techniques.

“For comparable traditional fabrication techniques, the hollow part of the micro-structure is extremely hard to accurately define, and usually takes multiple steps to complete the process. In our project, we are able to directly write the 3D micro-hollow structures in a straightforward way, with a minimum resolution of 100 nm,” Caizhi explained. “The Nanoscribe’s two-photon polymerization (TPP) technique is the corner stone of our fabrication project.”

“The key challenge lies in the design and fabrication of precise, sharp and durable micro-hollow structures for specific bio-applications,” added Caizhi. “The project was made possible by combined resources, including the cutting-edge fabrication and characterisation facilities in ANFF-Q, and the expert support from the ANFF-Q staff Doug Mair and Elliot Cheng.”

Achieving the optimised structures required systematic investigation of the fabrication parameters. The next step is to explore the potential biological applications of these precise micro-hollow structures.

“We are currently using these fabricated micro-structures for the resistive-pulse analysis of nano-particles. In the near future, we plan to extend the use of these micro-structures into other bio-application scenarios. The research outputs have great potential for real commercial applications,” said Caizhi.

Caizhi Liao is a member of the Trau Group within the Australian Institute for Bioengineering and Nanotechnology.