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

Compound mixtures represent an alternative, additional approach to DNA and synthetic sequence-defined macromolecules in the field of non-conventional molecular data storage, which may be useful depending on the target application. Here, we report a fast and efficient method for information storage in molecular mixtures by the direct use of commercially available chemicals and thus, zero synthetic steps need to be performed. As a proof of principle, a binary coding language is used for encoding words in ASCII or black and white pixels of a bitmap. This way, we stored a 25 × 25-pixel QR code (625 bits) and a picture of the same size. Decoding of the written information is achieved via spectroscopic (1H NMR) or chromatographic (gas chromatography) analysis. In addition, for a faster and automated read-out of the data, we developed a decoding software, which also orders the data sets according to an internal "ordering" standard. Molecular keys or anticounterfeiting are possible areas of application for information-containing compound mixtures.

Using precision polymer chemistry for plastics traceability and governance

Resolving the anonymity of plastic materials is critical for safeguarding the well-being of our natural environments and human health.

Sequence-Encoded Macromolecules with Increased Data Storage Capacity through a Thiol-Epoxy Reaction

Sequence-encoded oligo(thioether urethane)s with two different coding monomers per backbone unit were prepared via a solid phase, two-step iterative protocol based on thiolactone chemistry. The first step of the synthetic cycle consists of the thiolactone ring opening with a primary amine, whereby the in situ released thiol is immediately reacted with an epoxide. In the second step, the thiolactone group is reinstalled to initiate the next cycle. This strategy allows to introduce two different coding monomers per synthetic cycle, rendering the resulting macromolecules especially attractive in the area of (macro)molecular data storage because of their increased data storage capacity. Subsequently, the efficiency of the herein reported synthesis route and the applicability of the dual-encoded sequence-defined macromolecules as a potential data storage platform have been demonstrated by unraveling the exact monomer order using tandem mass spectrometry techniques.

Stimuli-Responsive Multifunctional Phenylboronic Acid Polymers Via Multicomponent Reactions: From Synthesis to Application

Stimuli-responsive polymers undergo changes under different environmental conditions. Among them, phenylboronic acid (PBA) containing polymers (PBA-polymers) are unique, because they can selectively react with diols to generate borates that are sensitive to pH, sugars, and H₂ O₂ , and can be effectively used to synthesize smart drug carriers and self-healing hydrogels. Recently, multifunctional PBA-polymers (MF-PBA-polymers) have been developed using multicomponent reactions (MCRs) to introduce PBA groups into polymer structures. These MF-PBA-polymers have features similar to those of traditional PBA-polymers; moreover, they exhibit additional properties, such as fluorescence, antimicrobial activity, and antioxidant capability, when different MCRs are used. In this mini review, the preparation of these MF-PBA-polymers are summarized and the new properties/functions that have been introduced into these polymers using different MCRs are discussed. The uses of these MF-PBA-polymers as fluorescent cell anticoagulants, drug carriers, and gelators of functional self-healing hydrogels have been discussed. Additionally, the challenges encountered during their preparation are discussed and also the future developments in this field are touched upon.

Sequence-controlled and sequence-defined polypeptoids via the Ugi reaction: synthesis and sequence-driven properties

Ugi reaction offers opportunities to facilely access unprecedented sequence control and sequence-driven properties in polypeptoids.

IrAAC-based construction of dual sequence-defined polytriazoles

One novel dual sequence-defined polytriazole structure was facilely achieved through an IrAAC-based iterative sequential growth strategy.

Regulation of tectonic sequences in chain-folding-directed monodisperse isomeric oligomers precisely tailored by Ugi-hydrosilylation orthogonal cycles

Monodisperse discrete oligomers with a tailored sequence of linkages within their backbones, which has been defined as a tectonic sequence, were precisely constructed through Ugi-4CRs coupled to hydrosilylation orthogonal cycles.

The solvent-free one-pot multicomponent tandem polymerization of 3,4-dihydropyrimidin-2(1H)-ones (DHPMs) catalyzed by ionic-liquid@Fe3O4 NPs: the development of polyamide gels

Solvent-free MCTP via Biginelli DHPMs catalyzed by a non-toxic magnetic catalyst (IL1–2@ Fe₃O₄) in a one-pot reaction was illustrated for the development of fluorescent non-conjugated polyamide gels.

Reading mixtures of uniform sequence-defined macromolecules to increase data storage capacity

In recent years, the field of molecular data storage has emerged from a niche to a vibrant research topic. Herein, we describe a simultaneous and automated read-out of data stored in mixtures of sequence-defined oligomers. Therefore, twelve different sequence-defined tetramers and three hexamers with different mass markers and side chains are successfully synthesised via iterative Passerini three-component reactions and subsequent deprotection steps. By programming a straightforward python script for ESI-MS/MS analysis, it is possible to automatically sequence and thus read-out the information stored in these oligomers within one second. Most importantly, we demonstrate that the use of mass-markers as starting compounds eases MS/MS data interpretation and furthermore allows the unambiguous reading of sequences of mixtures of sequence-defined oligomers. Thus, high data storage capacity considering the field of synthetic macromolecules (up to 64.5 bit in our examples) can be obtained without the need of synthesizing long sequences, but by mixing and simultaneously analysing shorter sequence-defined oligomers.

Ugi Reaction of Amino Acids: From Facile Synthesis of Polypeptoids to Sequence-Defined Macromolecules

Polypeptoids have been prepared and researched for more than 20 years. However, the efficient generation of polypeptoids and sequence-defined polypeptoids faces many challenges and difficulties. The Ugi reaction of amino acids has recently been introduced into polypeptoid chemistry as a new and powerful method to furnish polypeptoids. In the following mini review, the recent progress on the application of the Ugi reaction of amino acids in polypeptoid science, including polypeptoid from sustainable furfural, sequence-defined polypeptoids, and more is summarized. Moreover, the future development of the Ugi reaction of amino acids in polypeptoid science is discussed.

The Hantzsch Reaction in Polymer Chemistry: From Synthetic Methods to Applications

The Hantzcsh reaction is a robust four-component reaction for the efficient generation of 1,4-dihydropyridine (1,4-DHP) derivatives. Recently, this reaction has been introduced into polymer chemistry in order to develop polymers having 1,4-DHP structures in the main and/or side chains. The 1,4-DHP groups confer new properties/functions to the polymers. This mini-review summarizes the recent studies on the development of new functional polymers by using the Hantzsch reaction. Several synthetic approaches, including polycondensation, post-polymerization modification (PPM), monomer to polymer strategy, and one-pot strategy are introduced; different applications (protein conjugation, formaldehyde detection, drug carrier, and anti-bacterial adhesion) of the resulting polymers are emphasized. Meanwhile, the future development of the Hantzsch reaction in exploring new functional polymers is also discussed.

Dual sequence definition increases the data storage capacity of sequence-defined macromolecules

Sequence-defined macromolecules offer applications in the field of data storage. Challenges include synthesising precise and pure sequences, reading stored information and increasing data storage capacity. Herein, the synthesis of dual sequence-defined oligomers and their application for data storage is demonstrated. While applying the well-established Passerini three-component reaction, the degree of definition of the prepared monodisperse macromolecules is improved compared to previous reports by utilising nine specifically designed isocyanide monomers to introduce backbone definition. The monomers are combined with various aldehyde components to synthesise dual-sequence defined oligomers. Thus, the side chains and the backbones of these macromolecules can be varied independently, exhibiting increased molecular diversity and hence data storage capacity per repeat unit. In case of a dual sequence-defined pentamer, 33 bits are achieved in a single molecule. The oligomers are obtained in multigram scale and excellent purity. Sequential read-out by tandem ESI-MS/MS verifies the high data storage capacity of the prepared oligomers per repeat unit in comparison to other sequence defined macromolecules.

Sequence-defined l-glutamamide oligomers with pendant supramolecular motifs via iterative synthesis and orthogonal post-functionalization

One of the great challenges in polymer chemistry is to achieve discrete and sequence-defined synthetic polymers that fold in defined conformations and form well-defined three-dimensional structured particles.

Effects of crystallinity and dispersity on the self-assembly behavior of block co-oligomers in water

Dispersity and crystallinity affect the dimensions of lamellar structures formed by amphiphilic block co-oligomers in water as well as the reproducibility of sample formation; spherical and cylindrical morphologies are less affected.

Scalable Synthesis of Positively Charged Sequence-Defined Functional Polymers

Synthesizing and characterizing sequence-defined polymers with positively charged backbone are great challenges. By alternately processing Menschutkin reaction and Cu-catalyzed azide-alkyne cycloaddition reaction, we successfully synthesized series of scalable cationic sequence-defined polymers with quaternary ammonium backbone up to 12 repeating units and characterized their precise structures. Due to the dramatic polarity difference between weak polar feed molecules and strong polar target molecules, simple precipitation in weak polar solvents is enough to obtain pure sequence-defined polymers. Such a polar-inverse strategy (PIS), without protecting groups and solid support, offers extremely high yields up to 68% after 12 reaction steps (i.e., average yield >95% for each step), favoring cost-effective large-scale production. Because of the independent reactivity of selected functional groups, the cationic sequence-defined polymers are highly programmable, including backbone composition, sequence order, functional side groups, terminal groups and topological structure. Sequence information decoding is easily achieved according to Maldi-Tof mass spectrum without retrospecting its synthetic history, resulting in a great superiority in the field of information transmitting and reading. The resulting multifunctional sequence-defined polymers are water-soluble and positively charged, opening the avenue to bioapplications such as condensing DNA, gene transfection and drug delivery.

A versatile strategy for the synthesis of sequence-defined peptoids with side-chain and backbone diversity via amino acid building blocks

Designing artificial macromolecules with absolute sequence order is still a long-term challenge in polymer chemistry as opposed to natural biopolymers with perfectly defined sequences like proteins and DNA. Herein, we combined amino acid building blocks and iterative Ugi reactions for the de novo design and synthesis of sequence-defined peptoids. The highly efficient strategy provided excellent yields and enables multigram-scale synthesis of perfectly defined peptoids. This new strategy furnishes the broad structural diversity of side chains, as well as backbones. Importantly, the overall hydrophobicity and lower critical solution temperature (LCST) behaviours of these precisely defined peptoids can be logically altered by variation of the sequence. By following the same Ugi chemistry, these peptoids are also conjugated to DNA in a simple way, facilitating the development of novel therapeutics.

Monodisperse, sequence-defined macromolecules as a tool to evaluate the limits of ring-closing metathesis

Sequence-defined macromolecules of uniform size unlock the door to many new applications in polymer chemistry, such as structure/property or structure/activity relationship investigations, which cannot be conducted accurately, if the investigated macromolecules exhibit dispersity.

Synthesis of monodisperse isomeric oligomers based on meta-/para- and linear/star-monomer precursors with Ugi–hydrosilylation orthogonal cycles

Monodisperse oligomers were precisely prepared through orthogonal cycles of Ugi-4CRs and hydrosilylation coupling reactions, and the “monodisperse isomeric oligomers” were explored.

Direct comparison of solution and solid phase synthesis of sequence-defined macromolecules

Sequence-defined macromolecules of high molecular weight are synthesised by the combination of click chemistry with multicomponent reactions. The synthesis is performed on solid phase as well as in solution to directly compare the two approaches.

Multifunctional sequence-defined macromolecules for chemical data storage

Sequence-defined macromolecules consist of a defined chain length (single mass), end-groups, composition and topology and prove promising in application fields such as anti-counterfeiting, biological mimicking and data storage. Here we show the potential use of multifunctional sequence-defined macromolecules as a storage medium. As a proof-of-principle, we describe how short text fragments (human-readable data) and QR codes (machine-readable data) are encoded as a collection of oligomers and how the original data can be reconstructed. The amide-urethane containing oligomers are generated using an automated protecting-group free, two-step iterative protocol based on thiolactone chemistry. Tandem mass spectrometry techniques have been explored to provide detailed analysis of the oligomer sequences. We have developed the generic software tools Chemcoder for encoding/decoding binary data as a collection of multifunctional macromolecules and Chemreader for reconstructing oligomer sequences from mass spectra to automate the process of chemical writing and reading.

Recent Developments in Solid-Phase Strategies towards Synthetic, Sequence-Defined Macromolecules

Sequence-control in synthetic polymers is an important contemporary research area because it provides the opportunity to create completely novel materials for structure-function studies. This is especially relevant for biomimetic polymers, bioactive and information security materials. The level of control is strongly dependent and inherent upon the polymerization technique utilized. Today, the most established method yielding monodispersity and monomer sequence-definition is solid-phase synthesis. This Focus Review highlights recent advances in solid-phase strategies to access synthetic, sequence-defined macromolecules. Alternatives strategies towards sequence-defined macromolecules are also briefly summarized.

Peptide array functionalization via the Ugi four-component reaction

The Ugi four-component reaction was investigated as a tool for the functionalization of peptide arrays via post-synthetic side-chain modification, mimicking post-translational processes. Additionally, as a proof of concept for the synthesis of peptidomimetics on arrays, the integration of an Ugi unit into a growing peptide chain was demonstrated.

Ugi multicomponent reaction to prepare peptide–peptoid hybrid structures with diverse chemical functionalities

Sequence defined peptide–peptoid hybrids create new opportunities for self-assembled nano-structures.

Vanillin derived a carbonate dialdehyde and a carbonate diol: novel platform monomers for sustainable polymers synthesis

Vanillin has been regarded as one of the important biomass-based platform chemicals for aromatic polymers synthesis. Herein, novel symmetric bis(4-formyl-2-methoxyphenyl)carbonate (BFMC) and bis(4-(hydroxymethyl)-2-methoxyphenyl)carbonate (BHMC) polymeric monomers have been synthesized in high yields using vanillin as a raw chemical, which have been submitted for polymer synthesis via well-established polymeric strategies. A new class of poly(carbonate ester)s oligomers with amide moieties in their side chain can be prepared by using the BFMC as one of monomers via the Passerini three compound reaction (3CR). A new class of poly(carbonate ester)s oligomers and poly(carbonate urethane)s can be prepared via reactions between BHMC with dicarboxylic acid chlorides and diisocyanates, respectively. Their structure have been confirmed by ¹H NMR, ¹³C NMR and FTIR, and the gel permeation chromatograph (GPC) analysis shows that the Mn of poly(carbonate ester)s oligomers ranges from 3100 to 7900 with PDI between 1.31 and 1.65, and the Mn of poly(carbonate urethane)s ranges from 16 400 to 24 400 with PDI ranging from 1.36 to 2.17. The DSC analysis shows that the poly(carbonate ester)s oligomers have relative low T_g ranging from 37.4 to 74.1 °C, and the poly(carbonate urethane)s have T_g ranging from 97.3 to 138.3 °C, mainly correlating to the structure of dicarboxylic acid chlorides and diisocyanates used.

Novel classes of lignin-derived poly(carbonate ester)s, poly(carbonate ester)s pending amide moiety oligomers, and poly(carbonate urethane)s have been designed and synthesized.

Dual Sequence Control of Uniform Macromolecules through Consecutive Single Addition by Selective Passerini Reaction

The selective Passerini reactions of 4-formylbenzoic acid and 4-isocyanobenzoic acid with aliphatic isocyanides and aldehydes were utilized to synthesize sequence-defined uniform macromolecules. Our strategy does not involve any protecting groups or reactive group transformation steps and allows direct and consecutive propagation of sequence in each step. Introduction of diverse side groups by using different aliphatic components provided a range of sequence-defined uniform macromolecules in high yield and gram scale. The strategy also allows further Passerini self-coupling or cross-coupling of the formed sequences with other small molecules, affording polymers with up to 5098.3 Da and 20 side groups. Thus, this strategy will show promise for more efficient synthesis of new sequence-defined macromolecules.

Defining the Field of Sequence-Controlled Polymers

Over the last ten years, the development of synthetic polymers containing controlled monomer sequences has become a prominent topic in fundamental and applied polymer science. This emerging area is particularly broad and combines classical polymer chemistry tools with techniques imported from other domains such as biology, biochemistry, organic synthesis, engineering, and bioanalytics. Consequently, it also generates new structures, terminologies, and applications that are not within the traditional scope of polymer science. The term "sequence-controlled polymers" (SCPs) was recently proposed as a generic name to describe all these recent trends. However, since the field of SCPs has been growing very rapidly in recent literature, it is urgent to accurately define its scientific frontiers. In this important context, this review is an attempt to define, rationalize, and classify the field of SCPs. In particular, all synthetic approaches that have been reported for the synthesis of SCPs are discussed and categorized. In addition, the characterization tools, properties, and potential applications of these new polymers are described herein. Overall, this review serves as a reference guide for understanding the burgeoning field of SCPs.

Tailored Modification of Thioacrylates in a Versatile, Sequence-Defined Procedure

A strategy for the synthesis of sequence-defined oligomers using a selective side-group insertion approach making use of thiophenol-catalyzed amidation reactions is herein reported. In this context, a new thiolactone-based, multistep, iterative protocol is designed, utilizing thioacrylates in combination with solid-phase synthesis for step-by-step growth, resulting in sequence-defined oligomers. Sequence definition and structure variation are introduced by substituting the thioacrylate side groups with a wide variety of amines. The step-by-step growth of the oligomers is followed by liquid chromatography-mass spectrometry and high-resolution mass spectroscopy to determine both conversion and purity.