Desorption Electrospray Ionization (DESI) of Digital Polymers: Direct Tandem Mass Spectrometry Decoding and Imaging from Materials Surfaces

Abstract

Sequence‐defined synthetic polymers have recently emerged as an attractive medium to store information at the molecular level, where comonomers of the chains are defined as letters of an alphabet. The main read‐out methodology employed to retrieve such molecularly encoded information is tandem mass spectrometry (MS/MS), but a major current limitation remains the low storage capacity of readable chains. Ordering short oligomers at discrete locations onto surfaces to compose long messages is an attractive alternative to the difficult synthesis of long coded polymers. Yet, such surface storage requires a reliable sampling technique to be coupled on‐line with MS/MS. Because it combines fast surface extraction with efficient analyte ionization in ambient conditions, desorption electrospray ionization (DESI) is shown here to be perfectly suited to envisage bidimensional data storage. The present study demonstrates performances of DESI‐MS/MS at mapping oligomers used to write letters of a word, extracting digital labels from materials tagged for anticounterfeiting purposes, and imaging text written with coded polymeric inks.

Design of Abiological Digital Poly(phosphodiester)s

“…The characterization of the modified surfaces indicated the formation of 70-nm-thick films, in which digital layers are kept apart from one another by noncoded interlayers. The sequencing of such multilayered materials has not yet been reported, and the depth-profiling capabilities of DESI-MS/MS, recently shown to enable 2D imaging of sequence-coded oligomers, are currently investigated. We have also reported very recently the DNA-guided self-organization of PPDE chains .…”

Molecular data storage with zero synthetic effort and simple read-out

“…Either by an “internal” position mass tag 47 , 58 or a short ordering sequence 48 , or by the “external” arrangement of the samples on e.g. a surface 38 , 61 , 63 . We have so far shown the external arrangement of the samples for the data storage via NMR and GC, but we would also like to present a simple way for the internal approach.…”

“…In this context, Lutz et al have presented the potential of sequence-defined poly(phosphodiester)s 26 – 29 , oligo(triazole amide)s 30 , 31 , oligo(alkoxyamine amide)s 32 , 33 , oligourethanes 34 , 35 and oligo(alkoxyamine phosphodiester)s 36 , 37 as so-called digital polymers. For the latter two substance classes, decoding and imaging from a surface via DESI was shown recently 38 . Information-containing oligomers, obtained by a thia-maleimide Michael coupling and read-out using MALDI-TOF MS/MS, were reported by Zhang and coworkers 39 , 40 .…”

Fabrication and Decryption of a Microarray of Digital Dithiosuccinimide Oligomers

“…Therefore, a large amount of data can be encoded into DNA strings and decoded by DNA sequencing with the development of the high throughput microarray techniques ( Scheme a). [ 4–18 ] Inspired by this, chemists demonstrated sequence‐defined synthetic polymer can be used as an alternative data recorder, termed as digital polymer by Lutz et al [ 19–21 ] By employing two different monomers regarded as binary codes “0” and “1,” binary digital message can be encoded in the polymer chain through iterative synthetic strategies [ 22–35 ] and retrieved by tandem mass spectrometry (MS/MS) [ 36–46 ] as well as nanopore‐sequencing technique. [ 47,48 ] Compared to DNA, digital polymer displays higher chemical stability, better compatibility, and broader structural designability, [ 24,34,49,50 ] which improve the storage capacity [ 28,29,51–56 ] and facilitate decoding process [ 34,43,57–61 ] as well as applications.…”

“…Therefore, a large amount of data can be encoded into DNA strings and decoded by DNA sequencing with the development of the high throughput microarray techniques (Scheme 1a). [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] Inspired by this, chemists demonstrated sequence-defined synthetic polymer can be used as an alternative data recorder, termed as digital polymer by Lutz et al [19][20][21] By employing two different monomers regarded as binary codes "0" and "1," binary digital message can be encoded in the polymer chain through iterative synthetic strategies [22][23][24][25][26][27][28][29][30][31][32][33][34][35] and retrieved by tandem mass spectrometry (MS/MS) [36][37][38][39][40][41][42][43][44][45][46] as well as nanopore-sequencing technique. [47,48] Compared to DNA, digital polymer displays higher chemical stability, better compat...…”