Platelet encapsulation

In our work, we have tried to obtain exfoliated clay platelets encapsulated by polymer material. The challenges in clay encapsulation are shown schematically in Figure 3.1. 

Phillips WT, Klipper R, Fresne D, et al. Platelet reactivity with liposome-encapsulated hemoglobin in the rat. Exp Hematol 1997 25 1347. 

The details of the structural characteristics of individual constituents in the various carbon deposits were obtained by examination of a number of specimens from each experiment in a JEOL 100 CX transmission electron microscope that was fitted with a high resolution pole piece, capable of 0.18 nm lattice resolution. Suitable transmission specimens were prepared by applying a drop of an ultrasonic dispersion of the deposit in iso-butanol to a carbon support film. In many cases the solid carbon product was found to consist entirely of filamentous structures. Variations in the width of the filaments as a function of both catalyst composition and growth conditions were determined from the measurements of over 300 such structures in each specimen. In certain samples evidence was found for the existence of another type of ca naceous solid, a shell-like deposit in which metal particles appeared to be encapsulated by graphitic platelet structures. Selected area electron diffraction studies were performed to ascertain the overall crystalline order of the carbon filaments and the shell-like materials produced from the various catalyst systems. 

Patients with SCD should be evaluated as soon as possible for any fever greater than 38.5°C. Evaluation should be initiated as outlined in Table 101-2. Criteria for hospitalization include an infant less than 1 year old, history of previous bacteremia or sepsis, temperature greater than 40°C, WBC greater than 30,000/mm or less than 5000/ mm and/or platelets less than 100,000/mm, and evidence of other acute complications or toxic appearance. Outpatient management can be considered in older nontoxic children with reliable family caregivers. Antibiotic choice should provide adequate coverage for encapsulated organisms. 

The phenomenon of electroluminescence in organic soUds has been known since the 1960 s at that time. Pope et al. [1] and Helfrich and Schneider [2] discovered and investigated the electroluminescence of anthracene crystals between two electrodes, an anode and a cathode. The thickness of the highly-purified anthracene crystal platelets was large in these first experiments 10-20 /wm or 1-5 mm. The two electrodes on the surfaces of the crystal platelets were silver paste or liquid, highly concentrated solutions of NaCl. The necessary external voltages varied between 50 and 2000 V. Later, Williams and Schadt [3] were the first to construct a display , likewise from anthracene crystals, but with solid, laterally-structured electrodes, and they encapsulated it to prevent its degradation in the air. 

In the past, many groups have tried to encapsulate clay platelets inside latex particles. This encapsulation poses some extra challenges because of the tendency of the clay platelets to form stacks and card-house structures. Most of the attempts resulted in the so-called armored latex particles, i.e. clay platelets in the surface of the latex. Recently, natural and synthetic clays were successfully encapsulated. The anisotropy of the clay resulted in non-spherical latex particles (Figs. 5 and 6), either peanut-shaped [63] or flat [64]. Clay platelets also turned out to be good stabilizing agents for inverse Pickering emulsion polymerizations [65]. 

Fig. 6 Cryo-TEM picture of flat encapsulated gibbsite platelets. The polymerization has been performed from the surface with amphipatic RAFT agents. Note that some of the flat latex particles are seen from the face and some from the side. Secondary nucleation is also visible in this image [64]...

A similar strategy involving Laponite or MMT platelets grafted with polymerizable organotitanate and organosilane molecules was recently reported by Voorn et al. [285, 286]. Here, starved-feed soap-free emulsion polymerization of MMA conducted in the presence of the organoclay led to clay encapsulation. However the solid content was quite low (typically around 7%). 

This approach has been proven valid for the PP filled with platelet shaped and fibrous inclusions encapsulated in an elastomer interphase (30). Needless to say. 

Tactoid/agglomerate - polymer chains encapsulate stacks of clay platelets. 

Poly-L-glutamic acid Glycol-CS Platelets NR Model for live cell encapsulation [38]... 

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