Towards the development of a forensic DNA biosensor
In the forensic DNA field, quantitative PCR (qPCR) is commonly used to quantify the amount of deoxyribonucleic acid (DNA) in evidentiary samples. Though sensitive, this method is prone to error. Electrochemistry-based biosensors have been described as a possible alternative to qPCR. To this end, this work aims to develop a biosensor for forensic quantification by chemisorbing oligonucleotides functionalized to methylene blue onto the surface of gold screen-printed electrodes. Prior to this, the surface characteristics of the screen-printed gold electrode are examined through the use of a well-known redox probe Ru(NH3)62+/3+. Cyclic voltammetry (CV) and Square Wave voltammetry (SWV) were used to measure the current signal. The Randles-Sevčik equation was used to relate the area of the electrode with the current signal. Surface examinations of the gold screen-printed electrodes suggested these electrodes are suitable for use as a forensic DNA biosensor. Attempts to bind the oligonucleotide to the gold electrode were conducted. Though binding was successful, the resultant SWV signal suggested methods to chemisorb DNA onto gold surfaces require optimization.