Expanding the informational chemistries of life: peptide/RNA networks.

The RNA world hypothesis simplifies the complex biopolymer networks underlining the informational and metabolic needs of living systems to a single biopolymer scaffold. This simplification requires abiotic reaction cascades for the construction of RNA, and this chemistry remains the subject of active research. Here, we explore a complementary approach involving the design of dynamic peptide networks capable of amplifying encoded chemical information and setting the stage for mutualistic associations with RNA.

Design of multi-phase dynamic chemical networks.

Template-directed polymerization reactions enable the accurate storage and processing of nature's biopolymer information. This mutualistic relationship of nucleic acids and proteins, a network known as life's central dogma, is now marvellously complex, and the progressive steps necessary for creating the initial sequence and chain-length-specific polymer templates are lost to time. Here we design and construct dynamic polymerization networks that exploit metastable prion cross-β phases.

Reversible electronic nanoswitch based on DNA G-quadruplex conformation: a platform for single-step, reagentless potassium detection.

A novel on/off electronic nanoswitch is for the first time described based on the conformational change of DNA sequence possessing a single guanine (G)-rich stretch. Here, a thiolated, amine-containing G-rich DNA sequence is immobilized on the surface of gold electrode by means of facile sulfur-gold chemistry, followed by being labeled with redox-active ferrocene molecules serving as the signaling species. The surface-confined DNA sequence is able to change its configuration between rigid tetramolecular G-quadruplex and flexible single-stranded structures.

Homogeneous, unmodified gold nanoparticle-based colorimetric assay of hydrogen peroxide.

An unmodified gold nanoparticle-based colorimetric assay system in homogeneous format has been developed using hydrogen peroxide (H(2)O(2)) as a model analyte. H(2)O(2) is added to o-phenylenediamine/horseradish peroxidase solution, and allowed to react for 10 min. Then, unmodified gold nanoparticles that serve as "reaction indicators" are added to the reaction solution.

Reusable electrochemical sensing platform for highly sensitive detection of small molecules based on structure-switching signaling aptamers.

Aptamers are nucleic acids that have high affinity and selectivity for their target molecules. A target may induce the structure switching from a DNA/DNA duplex to a DNA/target complex. In the present study, a reusable electrochemical sensing platform based on structure-switching signaling aptamers for highly sensitive detection of small molecules is developed using adenosine as a model analyte.