development of model erythrocyte and creation of artificial erythrocyte by using an electro-hydrodynamic spraying operating in cone-jet mode

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In order to develop model erythrocyte (red blood cell) and to create artificial erythrocyte, we have created tiny, soft and elastic particles of alginic acid gel, of which diameter ranges from about 1 to 10 micrometers. lb do so, we have developed a double spraying method, in which a dilute solution of alginic acid has been made into tiny droplet by a pressurized spraying or an electro-hydrodynamic spraying method, and then these droplets have been chemically reacted with a droplet of calcium chloride by direct contact. This spherical shaped, soft and elastic particle has a size smaller than human erythrocyte, and so can pass smoothly through human blood capillaries.1.In order to evaluate the elasticity of the polymeric gel particle, we have observed its surface structure in water and have evaluated the local value of Young's modulus by using an atomic force microscope (AFM). As a result, it is observed that its surface is composed of aggregated tiny pebble-like particles from 100 to 2 … More 00 nm in diameter, and that its local Young's modulus is 2.6 to 3.7 MPa, which is much higher than that of human erythrocyte. The overall Young's modulus which have been obtained from the overall deformation of the gel particle is about 0.O5MPa.2.We have tried to create a micro-sized gel particle containing a bubble inside it. This type of particle will be very useful as an ultrasound contrast agent. We have succeeded in creating such particles, which have an inner structure that a thin membrane of polymeric gel coat a single micron-sized bubble.3.We have tried to develop alginic acid gel particles containing magnetic fluid as a new drug delivery system (DDS). Three different kinds of gel particle production methods, that is, an impinging 3-fluid spray method, an EHD spray method and a double spray method. As a result, uniformly dispersed aliginic acid gel particles less than 10 μ m in mean diameter, which are containing magnetic fluid, were produced by all the methods. Especially, spherical gel particles of several microns in diameter were produced by the EHD spraying method. Less