Flora Maitim Yrad

Title : Functionalization of Dextrin-capped gold nanoparticles with Oligodeoxynucleotides

Abstract:

Gold nanoparticle (AuNP) is a colloidal zerovalent nanoscale gold core generally capped by organic layer and dispersed in a solvent.  Their unique properties offer great potential applications in many fields including biosensing.  DNA-functionalized AuNPs are popular in biosensors due to their ability to recognize and interact with target molecules through DNA recognition sequences. The objective of this study was to functionalize dextrin capped AuNP with DNA oligonucleotide to produce a functional gold nanoparticle/reporter DNA (AuNP/rDNA) conjugate intended as reporter probe for a lateral flow biosensor for dengue RNA detection.  Synthesized dextrin-capped AuNP was mixed with a 20-base long DNA oligonucleotide thiolated at the 5’-end for ligand exchange reaction through salt-aging process. DNAfunctionalized AuNPs were characterized by color validation, UV-vis spectroscopy, and high-resolution transmission electron microscopy (HRTEM). The numbers of DNA strands attached to the AuNPs were quantified using AuNP decomposition by potassium cyanide and UV-vis spectroscopy measurements. The factors that affect functionalization were also determined. AuNPs with average core sizes of 7 and 10 nm were successfully functionalized with thiolated DNA molecules.  Well-functionalized AuNP retained the characteristic AuNP red color, exhibited AuNP surface plasmon resonance (SPR) bathochromic shift, and stable against aggregation at high salt concentrations. The DNA loading was found to be 9 ± 1 and 22 ± 2 DNA strands per particle of the 7 and 10 nm core sizes, respectively.  Dextrin capped AuNPs were successfully functionalized with 5’-end thiolated oligodeoxynucleotide and produced stable AuNP/rDNA conjugates. Functionalization was affected by the stability, concentration, and sizes of the dextrin capped AuNPs. 

Audience Take Away:

• The study reports that dextrin-capped gold nanoparticles can be successfully functionalized and produce stable AuNP/rDNA conjugates
• The study is helpful in the applications of gold nanoparticles as DNA reporter probes for lateral flow biosensor
• This research could be used by other faculty to expand their research or teaching on functionalization of dextrin capped gold nanoparticle and gain insights on the factors that affect DNA functionalization
• The study reports on the first attempt of quantifying the number of DNA strands attached to dextrin-capped gold nanoparticles

Biography:

Dr. Flora M. Yrad studied Chemistry at Silliman University and the University of San Carlos, Philippines. She conducted her dissertation research at the Nano-Biosensors Lab, Department of Biosystems and Agricultural Engineering, Michigan State University, USA funded by the United States Agency for International Development (USAID) Advanced Research Scholarship and Silliman Faculty Development Committee (FADECO) Doctoral Scholarship. She had published her works on modified synthesis of dextrincapped gold nanoparticles and dengue RNA detection using lateral flow biosensor. She graduated in 2019 with a PhD in Chemistry. She obtained the position of an Associate Professor at Silliman University, Dumaguete City, Philippines.