Rangées de graines.. © INRA, Elena Schweitzer © Fotolia

Our results

Contents
  1. Introduction
  2. Human milk digestion in the preterm infant: impact of technological treatments
  3. Research & Innovation 2017 - For Food and Biobased Products
  4. The way in which proteins aggregate when heated may change their sensitising potency
  5. Enhancing the viability of spray-dried probiotic bacteria by stimulating their stress tolerance
  6. To stick or not to stick? Pulling pili sheds new light on biofilm formation
  7. When biopolymers selfassemble: a balance between energy and entropy.
  8. Mimicking the gastrointestinal digestion in a lab-on-a-chip:the microdigester
  9. How a milk droplet becomes a powder grain
  10. Research & Innovation 2016 - For Food and Bioproducts
  11. A new process for the biorefining of plants
  12. Under the UV light : the bacterial membrane
  13. Reverse engineering or how to rebuild ... bread!
  14. Green Chemistry: a step towards lipid production in yeast
  15. Individually designed neo-enzymes for antibacterial vaccines
  16. Multi-scale mechanical modelling: from the nanometric scale to the macroscopic properties of bread crumb
  17. Minimill: 500 g to assess the milling value of soft wheats
  18. Microbial production of lipids for energy or chemical purposes
  19. The discrete role of ferulic acid in the assembly of lignified cell wall
  20. Eco-design of composites made from wood co-products
  21. Analysis of volatile compounds enables the authentication of a poultry production system
  22. Nanoparticles as capping agents for biopolymers microscopy
  23. Pasteurisation, UHT, microfiltration...All the processes don't affect the nutritional quality of milk in the same way
  24. Integration of expert knowledge applied to cheese ripening
  25. Controlling cheese mass loss during ripening
  26. The shape memory of starch
  27. Research & Innovation 2015 - For Food & Biobased Products
  28. Behaviour of casein micelles during milk filtering operations
  29. Overaccumulation of lipids by the yeast S. cerevisiae for the production of biokerosine
  30. Sequential ventilation in cheese ripening rooms: 50% electrical energy savings
  31. An innovative process to extract bioactive compounds from wheat
  32. Diffusion weighted MRI: a generic tool for the microimaging of lipids in food matrices
  33. Characterization of a major gene of anthocyanin biosynthesis in grape berry
  34. New enzyme activity detectors made from semi-reflective biopolymer nanolayers
  35. Improving our knowledge about the structure of the casein micelle
  36. Heating milk seems to favour the development of allergy in infants
  37. Fun with Shape
  38. Using volatile metabolites in meat products to detect livestock contamination by environmental micropollutants
  39. SensinMouth, when taste makes sense
  40. A decision support system for the fresh fruit and vegetable chain based on a knowledge engineering approach
  41. SOLEIL casts light on the 3D structure of proteins responsible for the stabilisation of storage lipids in oilseed plants
  42. A close-up view of the multi-scale protein assembly process
  43. Controlling the drying of infant dairy products by taking water-constituent interactions into account
  44. Polysccharide nanocrystals to stabilise pickering emulsions
  45. Discovery of new degradative enzymes of plant polysaccharides in the human intestinal microbiome
  46. A durum wheat flour adapted for the production of traditional baguettes
  47. Virtual modelling to guide the construction of « tailored-made » enzymes
  48. How far can we reduce the salt content of cooked meat products?
  49. Diffusion of organic substances in polymer materials: beyond existing scaling laws
  50. Smart Foams : various ways to destroy foams on demand !
  51. Dates, rich in tannins and yet neither bitter nor astringent
  52. Sodium content reduction in food
  53. Research & Innovation 2014

Fun with Shape

We demonstrated a new approach to synthesize monodisperse doughnut-shaped silica microparticles, in which uniform water-in-oil (W/O) emulsion droplets of silica sol were generated and subsequently underwent shrinkage through in situ rapid solvent diffusion within the microfluidic channel. Due to the non-uniform solvent diffusion across the droplet periphery, they finally solidify to form doughnut-shaped silica microparticles. The silica microstructures prepared in this way are monodisperse in both size and shape. By varying the sol concentration, flow conditions, silica microstructures with a size in the range of 7 to 50 µm were formed in a controlled manner. In addition, the impact of hydrodynamics parameters on the silica particle shape was studied, in which various shapes were obtained. This approach provides a starting point to control the geometry of a three-dimensional silica microstructure by droplet-based microfluidics. The exciting results could also promote new applications, for example, in shape-specific drug delivery carrier.

Updated on 06/13/2013
Published on 06/13/2013
Keywords:

Why shape control ?

Silica particles have demonstrated potentials in numerous fields such as separation science, drug delivery, or catalysis. However, their polydispersity, either in size or shape, presents a major challenge in understanding and controlling the mass-transport properties, which in turn introduces a striking lack, for example, in understanding the effect of  particle size and shape in the fields of drug delivery and material science. On the other hand, microfluidics provides a straightforward and robust approach to obtain highly monodisperse droplets, one at a time and with an incomparable degree of control over size.

Methodology and results

We used a simple droplet-based microfluidic approach to generate uniform water-in-oil (W/O) emulsion droplets of silica sol. Subsequently they underwent shrinkage through in situ rapid solvent diffusion within the microfluidic channels. The dispersed phase and continuous phase were silica sol and DMC (dimethyl carbonate), respectively. Although the two liquids are immiscible, water is in fact soluble in DMC up to 2.9 % in weight. Hence, subsequently to emulsification the sol droplets start to shrink due to water loss. A shape transition then take place, which will finally result in toroidal solid particles. The microparticles prepared in this way are all toroidal, this shape being an equilibrium one for thin closed membranes. They are also monodisperse in size, with a coefficient of variation of 3.5 % (see photo).

Microparticules. © INRA
Microparticules © INRA

More interestingly, we are not going to stop here. Further research results have showed that the silica particle shape can be controlled by playing with the hydrodynamic parameters during rapid solvent evaporation process, such as the Peclet number, Pe, the channel aspect ratio, etc. So far we have achieved silica particles with the shape of sphere, dimpled sphere, disk, bowl, doughnut (see photo). This research is the first trial to control the shape with microfluidic hydrodynamics. We believe it will shed new lights in the particle morphology control.

See also

  • Nie, Z.; Xu, S.; Seo, M.; Lewis, P.C.; Kumacheva, E. J. Am. Chem. Soc. 2005, 127, 8058.
  • Carroll, N. J.; Tathod, S. B.; Derbins, E.; Menndez, S.; Weitz, D. A.; Petsev, D. N. Langmuir 2008, 24, 658;
  • Chokkalingam, V.; Weidenhof, B.; Krämer, M.; Maier, W. F.; Herminghaus, S.; Seemann, R. Lab Chip 2010, 10, 1700.
  • Li, T.; Hu, W.; Liu, Y.; Huang, G.; Sumer, B. D.; Gao, J. Exp. Bio. Med. 2011, 236, 20.
  • Fang, A, Gaillard, C, Douliez, J-P. Chem. Mater. 2011, 23, 4660-4662.