Nanostructured membranes and capsules for biosensing, catalysis and drug delivery
This project concerns the design of membrane structures for various applications fabricated using the layer-by-layer method of self assembly.
The layer-by-layer (LbL) self-assembly method, which is based on the stepwise electrostatic assembly of oppositely charged species has emerged as a promising and versatile approach to construct nanostructured functional films onto charged surfaces either on planar substrates or colloids of various shapes and sizes. This flexible and facile procedure permits the coating of various substrates with uniform layers of diverse composition and controllable thickness (on a nanometer scale). This project will take two directions. One direction is to use biomolecules, nanoparticles, porphyrins and biocompatible polymers as building blocks to create new types of thin nanocomposite films and investigate their application in biosensing and catalysis. The other direction is to develop a novel pathway to fabricate nanoengineered core-shell structures by layer-by layer absorption of oppositely charged macromolecules onto colloidal particles, or in some cases onto porous supports that lead to tubular structures. This method has the capacity to employ a great variety of substances as shell constituents as well as core materials, which can be removed leaving hollow capsules. These hollow capsules have wide application in such areas as encapsulating bioactive molecules (proteins or drugs), working as confined nano- or microreactors, and modeling biological cells. Currently work on creating thin films containing porphyrin and using mesoporous silica nanoparticles as sacrificial templates for protein and drug immobilisation and delivery is underway in our laboratory.
Research achievements
A number of new applications of capsules and tubular structures produced using layer-by-layer deposition have been explored. These include biomimetic microcapsules that can be used as reaction vessels, titania nanotubes with photocatalytic properties and templated biolabels to be used for immunoassays.
Research highlights
Silica Templated Biolabels with Releasable Fluorophores for Immunoassays
A new method for the preparation of a novel class of biochemical assay labeling systems using hollow periodic mesoporous organosilica (H-PMO) particles as templates has been developed. This method results in very high loading of the fluorescent biolabel, which is very useful for high sensitivity labelling of antibodies.
Hybrid Nanocomposite Colloidal Crystals
Three-dimensional ordered colloidal crystals with polyelectrolyte shells containing metal (Ag) or semiconductor (CdS) nanoparticles have been fabricated using preformed colloidal crystals and in situ synthesis of NPs in the PE shell, by a combination of ion-exchange and reduction process. The resulted nanoparticle-containing crystals show the ability to tune the position of the stop band of the colloidal crystal by changing its lattice parameters and the shell composition.
Future plans and directions
Further development of the biolabel systems will be undertaken, with the emphasis being on increasing the dye loading by the use of different PMO particles, and investigating the use of quantum dots in place of fluorescent dyes to increase fluorescence intensity and minimise self-quenching.
Further investigation of the nanocomposite colloidal crystals will be undertaken, particularly as regards their spectroscopic properties.
Collaborations
Collaborator |
Organisation |
Dr Aimin Yu |
Murdoch University |
Prof Frank Caruso |
University of Melbourne |
