Building Digital Polymers Based On Thiol-Maleimide Michael Addition Reaction

With the rapid development of science and technology,traditional information storage technologies such as magnetic hard disk drives and solid state memories have not been able to fully meet people's needs.DNA is known as a genetic information carrier at the molecular level.Inspired by this,scientists designed the use of DNA as a carrier of data information storage,and achieved large-capacity storage and reading of data by the use of sophisticated sequencing technology.However,the stability of natural DNA and its compatibility with other materials are poor,which limits its practical application.Therefore,polymer scientists have proposed the use of sequence-precise synthetic polymers as carriers for information storage,which is called digital polymers.The digital polymer must have two conditions:(1)The number of units and the sequence structure of each polymer chain must be identical;(2)The existing sequencing technology can be used for,effective sequencing to achieve information reading.Digital polymer is the frontier research direction of polymer synthesis,and has great potential application value in the field of information storage and anti-counterfeiting.Due to the high level of challenges in its synthesis and sequencing,the academic research on digital polymers is just beginning.Therefore,the establishment of efficient synthesis methods and information reading methods for digital polymers has important theoretical research and practical application value.In this paper,we focus on the direction of digital polymer,and obtained two research results:(1)Based on thiol-maleimide Michael addition reaction,dithiosuccinimide(DTS)was used as a sequence assembly module in digital polymer chain to synthesize a series of digital polymers efficiently.(2)Using tandem mass spectrometry sequencing,DTS synergistically triggered the polymer chain cleavage to cause relative high mass spectrometry signals,and DTS was established as a sequencing tag module.The specific research contents of the efficient information reading method are as follows:(1)Since there are many steps for synthesizing a digital polymer,the efficiency of the synthesis method must be high.The Michael addition reaction of thiol-maleimide is a nonmetal-catalyzed,mild and efficient "click" reaction.In addition,maleimide is a functional group which can undergo many reactions,it has great advantages when it comes to synthesize digital polymers.In this chapter,we firstly synthesized the dimer(2mer)using the reversible Diels-Alder reaction of maleimide-furan and the Michael addition "click" reaction of thiol-maleimide,and then used N-Chlorosuccinimide to oxidize succinimide in 2mer to maleimide.The maleimide can undergo a Michael addition reaction with a plurality of thiol-containing small molecules to synthesize a dimer(RG-2mer)containing DTS.Finally,using RG-2mer containing DTS structure as a sequence assembly module,a series of digital polymers were synthesized accurately and efficiently.This work provides a method for synthesizing digital polymers based on sequence assembly modules and provides a new strategy for efficient and rapid building of digital polymers.(2)Tandem mass spectrometry is a commonly used sequencing method because of its high sensitivity and universal applicability.In this chapter,we used tandem mass spectrometry to sequence the synthesized digital polymers.It was found that the fragmentations corresponding to the DTS structure exhibited relative high mass spectrometry signals.Based on this discovery,this chapter used the DTS structure as a sequencing tag module to sequence a variety of digital polymers.The results showed that the DTS structure can be used as a sequencing tag module to read sequence information quickly and accurately.Finally,combined with computer simulation results,the mechanism of enhancement of mass spectrometry signal caused by DTS is discussed.The synergistic cleavage of the dithioether bond in the DTS structure during tandem mass spectrometry testing resulted in an enhancement of the mass spectrometry signal.The concept of this sequencing tag module provides a new way of the fast and accurate sequence information reading of digital polymers.