Organ printing particles

Besides topical and oral drug delivery, the resultant micro- to milimetre-sized particles are also suitable for other biomedical appUcations, like wound healing, tissue engineering scaffolds, cell reservoirs to implant inside damaged tissues and organ printing. 

Percin, G. Lundgren, T. Khuri-Yakub, B. 1998. Controlled ink-jet printing and deposition of organic polymers and solid particles. Appl. Phys. Lett. 73 2375-2377. 

With all pigments, the particle size distribution of the pigment as synthesised is the most important single factor in ensuring its optimum potential performance in use, but this potential can only be achieved if the particles are properly dispersed. To understand why particle size is so important it is necessary to look in some detail at the optical behaviour of tiny pigment particles dispersed in a transparent organic medium. The exact nature of this medium depends on whether the end-use is a paint, a printing ink or a plastic. 

Azo Reds and Maroons. Pigment Red 3 is one of the most populai organic red pigments used in industrial finishes. Its hue varies considerably with particle size and therefore several shades are commercially available. Its principal application is in air drying paints, and to a limited extent in printing inks. 

Gerstner W. 1966. Crystal form and particle size of organic pigments in printing inks and paints. J. Oil Col. Chem. Assoc. 49 954-973. 

As discussed in the following chapters, the vehicle is composed of the liquids (e.g., water, organic solvents, cross-linkable monomers), additives which bring a specific function (e.g., sm-factant, preservative, photoinitiator) and usually also a polymer which enables the binding of the functional molecules (e.g., colorants, conductive particles) to the substrate after printing. 

Obviously, one of the major concerns in the preparation of the conductive ink is the need for low electrical resistivity. Commercial conductive IJ inks based on silver particles have metal loadings ranging from approximately 20% to 80% by weight. Resistance of a pattern printed from a single pass of a print head is thus expected to be lower for formulations with higher sohds content. However, another factor that influences resistivity is the non-conductive organic load in the ink and in the sintered pattern. Therefore, when choosing... 

Carre V, Aubriet F, Scheepers PT, Krier G, MuUer JF. Potential of laser ablation and laser desorption mass spectrometry to characterize organic and inorganic environmental pollutants on dust particles. Rapid Com mu n Mass Spectrom 2005 19 871-80 [Epub ahead of print]. 

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