Process produces small spherical polymeric particles which have polycations bound to them. In emulsion form, particles present large positively charged surface which is available to absorb polyanions. This properly can be used in removing heparin from blood or bile acids from the digestive tract. Other anions, such as DNA and RNA, can also be removed from aqueous solutions

Rembaum, A.

English

NASA Technical Reports Server

December 1975
	 B75-10327 
is
NASA TECH BRIEF 
NASA Pasadena Office 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Covalent Bonding of Polvcations to Small Polymeric Particles 
[I
A newly developed process produces small spherical 
polymeric particles which have polycations bound to 
them. The particles are made by the copolymerization 
of vinyl monomers and 2-dimethylamino-ethylmeth-
acrylate, and they are modified by means of a 
quaternization (Menshutkin) reaction. The addition 
of dihalides and diamines causes the formation of 
polycations containing positive charges in their 
backbones. The number of polycation chains and the 
number of positive charges present in each chain may 
be varied. 
The particles can be utilized in medicine and 
biology. In an emulsion form, they present a large 
positively charged surface which is available to absorb 
polyanions. This property can be used in removing 
heparin, a polyanion, from the blood in patients with 
kidney malfunctions. [Also see NASA Tech Brief 
B75-10336 (NPO-13620)]. A similar technique can be 
used in removing bile acids from the digestive track. 
In addition, other anions, such as DNA and RNA, 
can also be removed from aqueous solutions. 
An experiment was conducted to test the effective-
ness of these particles in combining with heparin. The 
procedure was as follows: Spherical particles (1.66 .im 
in diameter) containing dimethylamino groups were 
stirred with 1,3-dibromopropane and 1,3-tetrameth-
ylaminopropane at room temperature in a dimeth-
ylformamide-methanol mixture (1:1 by volume for 24 
hours). The reaction product after the addition of 
water was centrifuged. The centrifugation in the 
presence of water was repeated until the supernatant 
was free of bromide ions. An aqueous suspension of 
polycation spheres (1 cm 3, 28 mg/cm 3) was added to 
20 ml of a heparin solution (1 mg/cm 3). After stirring 
the mixture for 15 minutes and filtration, the filtrate 
contained 0.04 mg/cm 3
 of heparin. 
By repeating this experiment under identical 
conditions but using 2 cm 3 of suspended charged 
spheres, no heparin could be detected in the filtrate by
means of azure A dye. The presence of positive 
charges on the spherical particles was ascertained by 
reaction with eosin Y. The latter is acidic dye which 
combines with 3,3-ionene to form an insoluble red 
precipitate. The ionene spheres were stirred in an 
aqueous solution with eosin Y for 10 minutes and then 
were centrifuged in distilled water 10 times. The 
spheres remained dark red. Polyhydroxyethylmeth-
acrylate spheres without dimethylamino groups served 
as control. After reaction with eosin Y and 
centrifugation, they were free of dye and appeared 
white. 
Further studies have to be conducted to see if the 
polycations have any toxic effects on the human body. 
By themselves they do, but their effect is significantly 
diminished after they combine with the polyanions. 
Notes: 
1. Recent studies have shown that ionene spheres kill 
leukemic EL4 cells by contact. 
2. Requests for further information may be directed 
to:
Technology Utilization Officer 
NASA Pasadena Office 
4800 Oak Grove Drive 
Pasadena, California 91103 
Reference: TSP75-10327 
Patent status: 
Title to this invention has been waived under the 
provisions of the National Aeronautics and Space Act 
[42 U.S.C. 2457W] to California Institute of 
Technology, Pasadena, California 91109. 
Source: Alan Rembaum of 
Caltech /JPL 
(NPO- 13487) 
Categories: 04 (Materials) 
05 (Life Sciences) 
This document was prepared under the sponsorship of the National
	
Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	
information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	
will be free from privately owned rights.
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Covalent bonding of polycations to small polymeric particles

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