In this work, we synthesized amino acid-containing poly(phenylacetylene)s and demonstrated the possibility of tuning their hierarchical structures by internal external perturbations. A valine-acetylene adduct, 4-ethynylbenzoyl-l-valine methyl ester (5), was readily polymerized [Rh(nbd)Cl]2, resultant "polyester" (1) selectively hydrolyzed KOH to its "polyacid" congener, poly(4-ethynylbenzoyl-l-valine) (2). (Supra)molecular polymers were characterized NMR, IR, UV, CD, AFM techniques. The...

A dynamic light scattering sensor for Pb(2+) was constructed with oligonucleotide-modified gold nanoparticles based upon its cleavage property DNAzyme.

A novel colorimetric sensing strategy for biomolecule assay has been developed, which integrates the signal amplification of hybridization chain reaction (HCR) with assembly gold nanoparticles (AuNPs) through triplex formation. In presence targets, HCR process can be triggered, products are specifically recognized by triplex-forming oligonucleotide (TFO) functionalized AuNPs, accompanying aggregation AuNPs and a dramatic absorbance change at 522 nm. addition, DNA hairpin probes form rigid...

Aptamers are a new class of synthetic DNA/RNA oligonucleotides generated from in vitro selection to selectively bind with various molecules. Due their molecular recognition capability for proteins, aptamers becoming promising reagents protein detection and drug development. In this study, the specific interaction between immunoglobulin E (IgE) its 37-nt aptamer has been measured directly by atomic force microscopy. The single-molecule unbinding IgE is determined using Poisson statistical...

A fluorescent biosensor for sequence-specific recognition of double-stranded DNA (dsDNA) was developed based upon the hybridization between dye-labeled single-stranded (ssDNA) and DNA. The fluorescence FAM-labeled quenched when it adsorbed on surface graphene oxide (GO). Upon addition target dsDNA, a homopyrimidine·homopurine part dsDNA Simian virus 40 (SV40) (4424–4440, gp6), occurred which induced desorbed from GO, turned dye. Under optimum conditions, enhanced intensity proportional to...

Early diagnosis of HIV biomarkers or genes is the key to reducing acquired immunodeficiency syndrome (AIDS) mortality. In our work, we developed a novel polymerase chain reaction–dynamic light scattering (PCR-DLS) assay for one-step sensitive detection DNA based on average-diameter change gold nanoparticles (AuNPs). This first PCR that makes use DLS technique as signal read-out, with particle size measured by increasing concentration target DNA. With help AuNP probes, this PCR-DLS can...

Precise evaluation of telomerase activity is highly crucial for early cancer diagnosis. In this study, a sensitive catalytic hairpin assembly-dynamic light scattering (CHA-DLS) assay detection developed by using the diameter change gold nanoparticle (AuNP) probes. The substrate primer can be extended in presence telomerase, producing extension product (TEP) with telomeric repeat units (TTAGGG)n at its 3'-end. TEP specifically trigger CHA process and form tremendous AuNPs-H1/H2...

Abstract An ultrasensitive and simple dynamic‐light‐scattering (DLS) assay for the sequence‐specific recognition of double‐stranded DNA (dsDNA) was developed based on detection average diameter change Au nanoparticle (AuNP) probes modified with oligonucleotides 5′‐TTTCTCTTCCTT‐ CTCTTC‐(T) 12 ‐SH‐3′ (Oligo 1) 5′‐TTCTTTCTTTTCTTTTTC‐(T) ‐ SH‐3′ 2). The target dsDNA composed two complementary oligonucleotides: 5′‐AAAGAGAAGGAAGAGAAGAAGAAAGAAAAGAAAAAG‐3′ 3)...

A sensitive fluorescent sensor for sequence-specific recognition of dsDNA was established with a molecular beacon (MB) based upon the formation parallel triplex DNA in presence Ag+ under neutral pH environment.

Abstract This work presents an amplified colorimetric biosensor for circulating tumor DNA (ctDNA), which associates the hybridization chain reaction (HCR) amplification with G-Quadruplex DNAzymes activity through triplex formation. In presence of ctDNA, HCR occurs. The resulting products are specially recognized by one sequence to include GGG repeat and other containing three repeats, synergetic effect asymmetrically split forming. Such design takes advantage property high peroxidase-like...

A sensitive colorimetric DNA biosensor for specific detection of single stranded oligonucleotide (ssDNA) is proposed in this paper. The based on silver-coated glass (SCGS) and G-quadruplex-hemin DNAzyme. Capture immobilized the surface SCGS by Ag-S bond. Signal can be used to hybridize with target which selected from Hepatitis B virus(HBV) gene as HBV DNA, HRP-mimicking DNAzyme formed through function a guanine-rich fragment signal catalyze oxidation...

Improving the sensitivity and reproducibility of surface-enhanced Raman spectroscopy (SERS) methods for detection bioactive molecules is crucial in biological process research clinical diagnosis. Herein, we designed a novel SERS platform cardiac troponin I (cTnI) by chemical–chemical redox cycle signal amplification strategy combined with dual ratiometric immunoassay. First, ascorbic acid (AA) was generated enzyme-assisted immunoreaction cTnI-anchored sandwich structure. Then, oxidized...

A novel localized surface plasmon resonance (LSPR) light-scattering sensor for Ag+ was developed with unmodified gold nanoparticles (AuNPs), based upon the specific recognition property of a cytosine–cytosine mismatched base pair. The addition induced oligonucleotide 5′-TAC ATA CAT ACT ATC TAT CTA-3′ to be desorbed from AuNPs, resulting in aggregation accompanied by dramatic enhancement LSPR intensity. intensity proportional concentration range 0.13–1.12 μM, limit detection 62.0 nM. results...

Copper ion (Cu2+) plays an important role in many biological reactions, and a suitable level of Cu2+ is necessary for the regular metabolism life. Thus developing sensitive simple method determination essential. Here, novel sensor was developed based on detecting average hydrodynamic diameter AuNPs by using dynamic light scattering (DLS). Cu2+-specific DNAzyme double-strand could not adsorb surface AuNPs, accordingly aggregation would occur with addition NaCl. However, cleave release...