Colloids in motion

 

We have a strong interest in fabricating colloidal systems in which we can control the motility of the particles when they are dispersed in a liquid. We are designing systems that can swim, shake, and swarm.

 

 
We are pleased that our work on using catalytic colloidal particles to control the permeability of vesicles was selected to feature on the Jan-Feb  2016  cover of  Materials Horizons . In this work, giant polymer vesicles which have membrane-embedded catalytically active manganese oxide particles are made using droplet-based microfluidics. It is demonstrated that these colloidal particles can regulate the membrane permeability of the polymersomes upon their exposure to, and catalytic reaction with, small amounts of dissolved hydrogen peroxide. Not only can we have triggered complete release whereby the vesicle gets destroyed through membrane rupture by the formed oxygen bubbles as illustrated on the cover, exposure to small amounts of dissolved hydrogen peroxide leads to temporary enhanced release until all hydrogen peroxide is consumed by the catalytic particles after which the membrane permeability restores itself to its passive characteristic value.    You can read more on our blog. You can read the paper here (open access) :  http://dx.doi.org/10.1039/C5MH00093A

We are pleased that our work on using catalytic colloidal particles to control the permeability of vesicles was selected to feature on the Jan-Feb 2016 cover of Materials Horizons. In this work, giant polymer vesicles which have membrane-embedded catalytically active manganese oxide particles are made using droplet-based microfluidics. It is demonstrated that these colloidal particles can regulate the membrane permeability of the polymersomes upon their exposure to, and catalytic reaction with, small amounts of dissolved hydrogen peroxide. Not only can we have triggered complete release whereby the vesicle gets destroyed through membrane rupture by the formed oxygen bubbles as illustrated on the cover, exposure to small amounts of dissolved hydrogen peroxide leads to temporary enhanced release until all hydrogen peroxide is consumed by the catalytic particles after which the membrane permeability restores itself to its passive characteristic value. 


You can read more on our blog. You can read the paper here (open access) : http://dx.doi.org/10.1039/C5MH00093A

Annular Dark Field Scanning TEM analysis of our matchstick particles which have a catalytic manganese oxide enriched head and a tail of silica. In our mechanistic study reported in  2015  in  Langmuir  we report an insight into the synthesis of silica-based “matchstick”-shaped colloidal particles, which are of interest in the area of self-propulsion on small length scales. The generation of aqueous emulsion droplets dispersed in an n-pentanol-rich continuous phase and their use as reaction centers allows for the fabrication of siliceous microparticles that exhibit anisotropy in both particle morphology, that is, a “matchstick” shape, and chemistry, that is, a transition-metal oxide-enriched head. We provide a series of kinetic studies to gain a mechanistic understanding and unravel the particle formation and growth processes. Additionally, we demonstrate the ability to select the aspect ratio of the “matchstick” particle in a straightforward manner.  More information can be found on our  blog . You can read the paper here:  http://dx.doi.org/10.1021/acs.langmuir.5b02645

Annular Dark Field Scanning TEM analysis of our matchstick particles which have a catalytic manganese oxide enriched head and a tail of silica. In our mechanistic study reported in 2015 in Langmuir we report an insight into the synthesis of silica-based “matchstick”-shaped colloidal particles, which are of interest in the area of self-propulsion on small length scales. The generation of aqueous emulsion droplets dispersed in an n-pentanol-rich continuous phase and their use as reaction centers allows for the fabrication of siliceous microparticles that exhibit anisotropy in both particle morphology, that is, a “matchstick” shape, and chemistry, that is, a transition-metal oxide-enriched head. We provide a series of kinetic studies to gain a mechanistic understanding and unravel the particle formation and growth processes. Additionally, we demonstrate the ability to select the aspect ratio of the “matchstick” particle in a straightforward manner.

More information can be found on our blog. You can read the paper here: http://dx.doi.org/10.1021/acs.langmuir.5b02645

In our  2014   Materials Horizons  paper which made the inner cover of the first issue of this journal we report the discovery of our matchstick particles and we demonstrate that they can undergo chemotaxis, as they self-propel upwards on a hydrogen peroxide gradient in water. You can read the paper here:  http://dx.doi.org/10.1039/C3MH00003F

In our 2014 Materials Horizons paper which made the inner cover of the first issue of this journal we report the discovery of our matchstick particles and we demonstrate that they can undergo chemotaxis, as they self-propel upwards on a hydrogen peroxide gradient in water. You can read the paper here: http://dx.doi.org/10.1039/C3MH00003F