Biomedical subjects

Derek J Hansford

Publications and source records attributed to Derek J Hansford.

3 recordsLinked to original sources

PubMed2006

Fabrication of polymeric microparticles for drug delivery by soft lithography.

Soft lithographic techniques were used to fabricate polymeric microparticles for drug delivery applications. The microparticles were made of thermoplastics and thermosets from different types of precursors including reactive resin and polymer solutions in organic solvents or water. The microparticles produced using these methods were made of widely used polymers for drug delivery with highly uniform sizes, plate-like morphology, and well-defined lateral sizes and shapes, making them potentially useful for drug delivery applications and as platform for the construction of multi-functional drug delivery devices.

Biocompatible Materials↗

PubMed2005

Self-folding of three-dimensional hydrogel microstructures.

This letter describes the fabrication of three-dimensional particulate-like hydrogel microstructures using a combination of soft lithography and volume expansion induced self-folding. Bilayer structures are produced by solvent casting and photocuring of liquid resins. They curl into three-dimensional (3D) structures upon contacting with water due to differential swelling of the two layers. The curvature can be controlled by adjusting the polymer composition of the primary swelling layer. A simple semiempirical mathematical model is used to predict this self-folding behavior. By designing the two-dimensional (2D) shapes of the bilayers, this technique can lead to complicated 3D microstructures.

Journal Article↗

PubMed2003

Effect of multivalent ions on electroosmotic flow in micro- and nanochannels.

In this work, the effect of multivalent ions on electroosmotic flow is investigated for multiple electrolyte components. The cases studied include incorporating Ca2+ and HPO4(2-) and other monovalent ions, such as K+ and H2PO4-, into an aqueous NaCl solution. The governing equations are derived and solved numerically. The boundary conditions for the governing equations are obtained from the electrochemical equilibrium requirements. In comparison with monovalent ions, the results show that in micro- and nanochannels having fixed surface charges, multivalent counterions, even in very small amounts, reduce electroosmotic flow significantly, while the multivalent co-ions have little effect on the electroosmotic flow. Due to the enhanced ion-wall interactions multivalent counterions compose the majority of ions in the electric double layer (EDL), causing a decrease of net charge at the surface.

Electrochemistry↗