Singapore's Institute of Bioengineering and Nanotechnology (IBN) has developed the first tri-continuous mesoporous material using a unique surfactant template. This completely new porous structure previously been predicted only mathematically.

In the current Nature Chemistry, the IBN scientists report that this novel material, named IBN-9 after the research institute, is the first hexagonal nanoscale construct with 3 unconnected interwoven channels. It is by far the most complex mesoporous nanostructure to have been synthesized in real-life and represents a new class of mesoporous materials, which consist of pores of 2-50 nanometers in size.

Mesoporous silica has well-defined nanochannel structures that are formed over templates via self-assembly processes. Mesoporous silica materials have huge surface areas, making them ideal for use as catalysts to facilitate chemical reactions. Their uniform nanometersized pores allow them to separate molecules by size difference. Their pores may also be used to trap drug molecules for controlled drug release. Therefore, the ability to tailor the pore structure of mesoporous material is of fundamental importance for various chemical and biological applications.

"IBN-9 demonstrates that it is possible to create three interwoven but independent pore channel systems along with a unique nano-fiber morphology," said Jackie Y. Ying, Ph.D., who led this research.

"Such a mesostructure makes distinct diffusion rates in different directions possible. This property would be very attractive for gas separation and drug delivery systems" added Dr. Ying, Executive Director of IBN, which is part of Singapore's A*STAR (Agency for Science, Technology and Research).

There has been tremendous interest about tailoring mesoporous materials with unique pore structures and pore sizes. The most complex of these were the bi-continuous structures, which contain two unconnected interwoven channels. These materials are synthesized via self-assembly of silica around surfactant templates.

IBN researchers successfully synthesized the first tri-continuous mesoporous structure by using a specially designed surfactant template, N,N-dimethyl-L-phenylalanine. This surfactant has a unique tunable head-group as well as a long hydrocarbon tail that has variable levels of hydrophobic (water-repellent) qualities. By systematically changing the synthesis conditions using this surfactant, IBN researchers are able to achieve structures with increasing mean curvatures from the bi-continuous cubic IBN-6 to the tri-continuous 3D hexagonal IBN-9, and finally to the 2D hexagonal IBN-10. The structural complexity of IBN-9 and its sister materials opens the possibility of creating even more complex multi-continuous mesostructures.

Notes:

The research described in this news release is published in the following paper: Y. Han, D. Zhang, L. L. Chng, J. Sun, L, Zhao, X. Zou and J. Y. Ying, "A Tri-Continuous Mesoporous Material, IBN-9, with a Silica Pore Wall Following a Hexagonal Minimal Surface," Nature Chemistry (2009).

The mathematical prediction mentioned in the first paragraph was published in this paper: S. T. Hyde and G. E. Schröder, "Novel Surfactant Mesostructural Topologies: Between Lamellae and Columnar (Hexagonal) Forms," Current Opinion in Colloid and Interface Science, 8 (2003) 5-14.

Institute of Bioengineering and Nanotechnology:

The Institute of Bioengineering and Nanotechnology (IBN) was established in 2003 and is spearheaded by its Executive Director Jackie Yi Ru Ying, Ph.D., who has been on the Massachusetts Institute of Technology's Chemical Engineering faculty since 1992, and was among the youngest to be promoted to Professor in 2001. In 2008, Dr. Ying was recognized as one of "One Hundred Engineers of the Modern Era" by the American Institute of Chemical Engineers for her groundbreaking work on nanostructure manipulations, nanoporous materials and host matrices for quantum dots and wires.

Under her direction, IBN conducts research at the cutting-edge of bioengineering and nanotechnology. Its programs are geared towards linking multiple disciplines across all fields in engineering, science and medicine to produce research breakthroughs that will improve healthcare and our quality of life.

IBN's research activities are focused in the following areas: Drug and Gene Delivery, where the controlled release of therapeutics involve the use of functionalized polymers, hydrogels and biologics for targeting diseased cells and organs, and for responding to specific biological stimuli.

Cell and Tissue Engineering, where biomimicking materials, stem cell technology,microfluidic systems and bioimaging tools are combined to develop novel approaches to regenerative medicine and artificial organs.

Biosensors and Biodevices, which involve nanotechnology and microfabricated platforms for high-throughput biomarkers screening, automated biologics synthesis and rapid disease diagnosis.

Pharmaceuticals Synthesis and Nanobiotechnology, which encompasses the efficient catalytic synthesis of chiral pharmaceuticals, and new nanocomposite materials for sustainable technology and alternative energy generation. IBN's innovative research is aimed at creating new knowledge and intellectual properties in the emerging fields of bioengineering and nanotechnology to attract top-notch researchers and business partners to Singapore. Since 2003, IBN researchers have produced a total of 490 papers published/in press, of which 227 were published in journals with impact factor greater than 3. IBN also plays an active role in technology transfer and spinning off companies, linking the research institute and industrial partners to other global institutions.

As of March 2009, IBN has filed 687 patent applications on its inventions and the institute is currently looking for partners for collaboration and commercialization of its portfolio of technologies. IBN's current staff strength stands at around 170 scientists, engineers and doctors. With its multinational and multidisciplinary research staff, the institute is geared towards generating new biomaterials, devices, systems, equi equipment and processes to boost Singapore's economy in the fast-growing biomedical sector.

IBN is also committed to nurturing young minds, and the institute acts as a training ground for PhD students and undergraduates. In October 2003, IBN initiated a Youth Research Program to open its doors to university students, as well as students and teachers from various secondary schools and junior colleges. It has since reached out to more than 28,900 students and teachers from 201 local and overseas schools and institutions.

Source:
Cathy Yarbrough
Agency for Science, Technology and Research (A*STAR), Singapore