Chemical amplification with encapsulated reagents

Abstract

Autocatalysis and chemical amplification are characteristic properties of living systems, and they give rise to behaviors such as increased sensitivity, responsiveness, and self-replication. Here we report a synthetic system in which a unique form of compartmentalization leads to nonlinear, autocatalytic behavior. The compartment is a reversibly formed capsule in which a reagent is sequestered. Reaction products displace the reagent from the capsule into solution and the reaction rate is accelerated. The resulting selfregulation is sensitive to the highly selective molecular recognition properties of the capsule.

Autonomous Fueled Mechanical Replication of Nucleic Acid Templates for the Amplified Optical Detection of DNA

“…The bands of the foreign DNA or the normal gene 2 a and the bands of the hairpin 1 and the fuel substrate 7 are unaffected after 1 h of reaction, implying that no scission takes place. Lanes 15,16,and 17 show the analysis of the mutant 2 according to Figure 3 at t = 0, 30, and 60 min of reaction, respectively. The bands g and h, which correspond to the hairpin 1 and the fuel 7, are depleted, implying that scission occurs.…”

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The self-replication of molecular or macromolecular units has attracted substantial research efforts over the past fifteen years, and the relevance of these systems to prebiotic chemical evolution and optimal synthetic machines has been discussed.[1] The different replication systems that have been developed include nucleotide-based oligomers, [2][3][4][5][6] peptides, [7][8][9][10] molecular conjugates, [11,12] micelles, [13] and vesicles.[14] The application of self-replicating systems is scarce, and only chemical amplification in synthesis [15,16] or the preparation of nanoparticles in self-reproducing micelles [17] were demonstrated. Amplification is a central aspect in bioanalytical science, and enzyme conjugates, [18] DNAzymes, [19] and, more recently, nanoparticles [20] have been widely used as amplifying labels for biorecognition events.

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Dmitry M. Rudkevich: A Tribute Seven Years after His Premature Passing

“…In 1996, Rudkevich joined the group of Prof. Julius Rebek, Jr., at Massachusetts Institute of Technology (Boston, MA, USA) and later at The Scripps Research Institute (La Jolla, CA, USA), where he simultaneously carried out several research projects on self-assembled supramolecular hosts: molecular capsules formed and stabilized by non-covalent (hydrogen) bonding, [10][11][12][13] resorcinarenes, [14] resorcinarene-based cavitands (deep cavity [15,16] and ''self-folding'' cavitands [17][18][19][20][21] ), and encapsulation processes. [22,23] Here, some new concepts were developed in supramolecular chemistry, such as chemical amplification of organic reactions within molecular capsules [24,25] ; a new type of stereoisomerism in a confined cavity of the supramolecular host: due to the spatial relationships between two encapsulated molecules of one guest (toluene or c-picoline), they became stereoisomers (by the supramolecular nature), but each of these stereoisomers forms and exists only in the presence of a second co-guest [26] ; and a very unusual encapsulation of hetero-guest pairs by the molecular capsule, which is possible because of mechanical barriers within this capsule. [27] In 1997, he was promoted to Research Assistant Professor at…”

Experimental and computational probes of the space in a self-assembled capsule

“…Such cavitands can maintain their conformations through intramolecular hydrogen bonds along the upper rim (8-9), or, when intermolecular hydrogen bonding is possible, the formation of capsules 2.2 can occur (10)(11)(12). This capsule presents guests with an electronic environment dominated by the eight benzene rings at each end (13)(14)(15). The four aryls at each of the resorcinarene ends impart an intense magnetic anisotropy: proton nuclei held near these ends show upfield shifts of up to 5 ppm in their NMR signals.…”