Colorimetric detection of c-Kit mutations using electrostatic attraction induced aggregation of peptide nucleic acid modified gold nanoparticles

Using gold nanoparticles to detect single-nucleotide polymorphisms: toward liquid biopsy

The possibility of detecting genetic mutations rapidly in physiological media through liquid biopsy has attracted the attention within the materials science community. The physical properties of nanoparticles combined with robust transduction methods ensure an improved sensitivity and specificity of a given assay and its implementation into point-of-care devices for common use. Covering the last twenty years, this review gives an overview of the state-of-the-art of the research on the use of gold nanoparticles in the development of colorimetric biosensors for the detection of single-nucleotide polymorphism as cancer biomarker. We discuss the main mechanisms of the assays that either are assisted by DNA-based molecular machines or by enzymatic reactions, summarize their performance and provide an outlook towards future developments.

Rapid label-free visual detection of KRAS mutations using peptide nucleic acid and unmodified gold nanoparticles

Colorectal cancer (CRC) is among the most commonly diagnosed cancers worldwide.

Versatility of peptide nucleic acids (PNAs): role in chemical biology, drug discovery, and origins of life

This review briefly discussed nomenclature, synthesis, chemistry, and biophysical properties of a plethora of PNA derivatives reported since the discovery of aegPNA. Different synthetic methods and structural analogs of PNA synthesized till date were also discussed. An insight was gained into various chemical, physical, and biological properties of PNA which make it preferable over all other classes of modified nucleic acid analogs. Thereafter, various approaches with special attention to the practical constraints, characteristics, and inherent drawbacks leading to the delay in the development of PNA as gene therapeutic drug were outlined. An explicit account of the successful application of PNA in different areas of research such as antisense and antigene strategies, diagnostics, molecular probes, and so forth was described along with the current status of PNA as gene therapeutic drug. Further, the plausibility of the existence of PNA and its role in primordial chemistry, that is, origin of life was explored in an endeavor to comprehend the mystery and open up its deepest secrets ever engaging and challenging the human intellect. We finally concluded it with a discussion on the future prospects of PNA technology in the field of therapeutics, diagnostics, and origin of life.

Peptide nucleic acid-mediated aggregation of reduced graphene oxides and label-free detection of DNA mutation

We have investigated peptide nucleic acid (PNA)-mediated aggregation of reduced graphene oxide (rGO) sheets. Addition of PNA into suspension of rGOs resulted in aggregation of rGOs, which could be easily detected with the naked eye. To elucidate the mechanism of rGO aggregation, we monitored the reaction by transmission electron microscopy, zeta potential measurement, and UV-vis spectroscopy. Our findings suggest that PNA adsorbed on the rGO surface and then acted as a cross-linker to induce aggregation. We also tested the effects of different nucleic acids on rGO aggregation and found that not only the single-stranded DNA, but also the PNA-DNA complex, could stabilize the suspension against aggregation through electrostatic repulsion. Based on our understanding on rGO aggregation, we attempted to detect mutations in epidermal growth factor receptor (EGFR) by designing PNA probe to be complementary to the mutant type DNA sequence. Our results showed that PNA-mediated rGO aggregation could successfully be used to detect mutations in EGFR with high selectivity and sensitivity.

Peptide nucleic acids: a review on recent patents and technology transfer

INTRODUCTION

DNA/RNA-based drugs are considered of major interest in molecular diagnosis and nonviral gene therapy. In this field, peptide nucleic acids (PNAs, DNA analogs in which the sugar-phosphate backbone is replaced by N-(2-aminoethyl)glycine units or similar building blocks) have been demonstrated to be excellent candidates as diagnostic reagents and biodrugs.

AREAS COVERED

Recent (2002 - 2013) patents based on studies on development of PNA analogs, delivery systems for PNAs, applications of PNAs in molecular diagnosis, and use of PNA for innovative therapeutic protocols.

EXPERT OPINION

PNAs are unique reagents in molecular diagnosis and have been proven to be very active and specific for alteration of gene expression, despite the fact that solubility and uptake by target cells can be limiting factors. Accordingly, patents on PNAs have taken in great consideration delivery strategies. PNAs have been proven stable and effective in vivo, despite the fact that possible long-term toxicity should be considered. For possible clinical applications, the use of PNA molecules in combination with drugs already employed in therapy has been suggested. Considering the patents available and the results on in vivo testing on animal models, we expect in the near future relevant PNA-based clinical trials.