3-[Dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]azaniumyl]propane-1-sulfonate (DMAPS) is a hygroscopic zwitterionic monomer for the synthesis of polysulfobetaine. Polysulfobetaine is an electrically neutral polymer, which contains both cationic and anionic groups in one monomer unit, and has interesting properties such as anti-electrolyte behavior in saline solution, biocompatibility and blood phase Capacitive. These properties make polysulfobetaine useful in many biomedical applications, such as drug delivery and pharmaceutical formulations.

Fig 1. Chemical structure formula and three-dimensional structure of 3-[Dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]azaniumyl]propane-1-sulfonate

As 3-[Dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]azaniumyl]propane-1-sulfonate is hygroscopic, each monomer unit contains a maximum of one molecule of water. The material should be stored in a cool, dry place, and some reaction conditions may require the removal of water before polymerization.DMAPS is a reagent in the synthesis of PVA/SBMA crosslinked hydrogels used in tissue mimicking, vascular cell culturing and implanting. For use in soft-tissue surgery and keeping it minimally invasive[1,2].It demonstrated that the synthesis of poly(sulfobetain methacrylate) (p(SBMA)) hydrogels of micro dimensions by inverse suspension polymerization of a zwitterionic monomer DMAPS. The prepared microgels were used as microreactors for the synthesis of nickel (Ni) nanoparticles by in situ reduction of Ni (II) loaded into microgels from an aqueous medium[3].

The preparation method of highly flexible zwitterionic hydrogel is as follows: 

DMAPS monomer, a cross-linking agent and an initiator are dissolved in deionized water, said DMAPS monomer is 1.0 to 2.0 g / ml, and both ends of the molecular chain of the crosslinker molecule are With a double bond, the middle of the molecular chain is the "oxy-carbon-carbon-oxygen" backbone structure, which is a polyethylene glycol molecular segment. The molecular weight of the cross-linking agent is 330 ~ 20,000, and the initiator and monomer The unsaturated bonds on the segment molecules were used to prepare the zwitterionic DMAPS hydrogel through free radical polymerization. The obtained hydrogel was soaked in water for 5-8 days, and the first three days were changed every 3-5 hours. Once water, water is changed every 12 hours in the following days to remove excess monomers, initiators and cross-linking agents; wherein the mass of the cross-linking agent is 0.1% of the mass of the monomers.

By modifying the concentration of DMAPS monomer, crosslinking agent and initiator concentration, zwitterionic DMAPS with high flexibility was obtained. Hydrogels. The DMAPS hydrogel prepared by this method not only has good mechanical properties and resistance to protein adsorption and cell adsorption through the interaction between a large number of positive and negative charges of SB units, but also has temperature sensitivity and salt ion corresponding and self-repairing properties. The invention can further expand the application of amphoteric ion-based hydrogels in the field of biomedical tissue engineering, especially in some fields requiring certain mechanical strength, such as artificial joints, blood vessels and the like. At the same time, this preparation method avoids the traditional modification of the zwitterionic DMAPS main chain by grafting, which is simpler and easier, and the entire process is easy to industrialize.

References

[1]Jian, S. et al.: J. Mech. Bwhav. Biomed. Mat., 4, 1228 (2011).
[2]Xu, S. et al.: Ann. Tech. Conf. Soc. Plastics Emg., 71, 1032 (2013).
[3]Betaine microgel preparation from 2-(methacryloyloxy) ethyl] dimethyl (3-sulfopropyl) ammonium hydroxide and its use as a catalyst system[J]. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2015, 486:29-37.
[4]https://pubchem.ncbi.nlm.nih.gov/compound/3034140
[5]https://www.chemspider.com/Chemical-Structure.2298648.html?rid=a8b730a2-5b92-4771-ac6b-33658d512233