Gna Ahn

Bioengineered aptamer-nanoconjugates for cancer theragnosis

Early detection and treatment of cancer is of global interest as cancer is one of the leading causes of death worldwide. As the survival rate of cancer patients is closely related to its detection at an early stage, there is an urgent need to develop detection techniques that are fast, reliable, and easily available. Aptamers are single stranded DNA- and RNA- based oligonucleotides that can bind to their targets with high affinity and specificity. Their small size, excellent chemical stability, and low immunogenicity enable them to become alternatives to antibodies in cancer theragnostic approaches with cancer imaging and therapy applications.Purpose of review: In this review, we discuss the role of aptamer-nanomaterials conjugates as novel molecular tools for enhanced diagnosis (biosensing and nano-imaging) and therapy (drug delivery) of cancer cells.

Poly-adenine-Coupled LAMP Barcoding to Detect Apple Scar Skin Viroid

Apple Scar Skin Viroid (ASSVd), a nonprotein coding, circular RNA pathogen is relatively difficult to detect by immunoassay. We report here a one-step reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay to improve selectivity for diagnostic use in detecting ASSVd in plants. ASSVd RT-LAMP was accelerated using loop primers and was found to be highly sensitive with a detection limit of 104 copies of cDNA-ASSVd within 30 min. Real-time LAMP and melting curve analysis could differentiate between the true-positive LAMP amplicons and false-positive nonspecific primer amplification products. The optimized RT-LAMP was then followed by the addition of nonthiolated AuNP:poly-adenine (A10)-ASSVd LAMP barcodes, showing a high authentication capacity with colorimetric changes. This type of barcoding assay is a potential alternative for rapid and multiple viroid diagnosis, providing for visible sensing in the field that can be applied to viroid-free planting.

Detection of endotoxins using nanomaterials

An endotoxin is a lipopolysaccharide complex that is associated with the outer membrane of gram negative bacteria, and even a small amount can trigger strong exothermic activity. Pharmaceutical and food products can be contaminated with endotoxins, so there is a strict need to control them. A limulus amoebocyte lysate (LAL) assay is a standard endotoxin detection method that is highly sensitive and easy to use, but it has disadvantages in that the sample preparation is a complex process, it takes a long time to confirm the presence of endotoxins, and it requires a controlled workplace. Recently, endotoxin detection using nanomaterials has been gaining attention, and this review reports on the latest endotoxin detection methods using gold nanoparticles, magnetic nanoparticles, quantum dots, and carbon materials, among different nanomaterials, and it also introduces the future prospect of endotoxin detection.