Applications Of Nanotechnology For Microbial Diagnostics To Combat Infectious Diseases

Abstract

Various pathogens cause disease outbreaks in plants, animals and humans that have led to fatalities and economic losses. To effectively prevent these outbreaks, disease surveillance and early diagnosis is crucial. While there are some standard detection methods used currently, they are expensive and suffer from long turnaround times that delay treatment and disease control actions. Since nucleic acid detection techniques are preferred as they offer target gene specific diagnosis, significant research has been directed to simplifying them for faster and more accurate identification. Several isothermal amplification methods have been explored for this purpose, among which loop mediated isothermal amplification (LAMP) offers a simple, cost-effective, and reliable approach for rapid onsite pathogen detection. This study discusses the design and optimization of a LAMP assay for the detection of the oak wilt fungus, Bretziella fagacearum, as the model organism. Oak wilt disease is a significant threat to oak (Quercus spp.) tree health in the United States and eastern Canada. Without management the disease may cause dramatic changes to natural and urban ecosystems. Early and accurate diagnosis is necessary for timely treatment. The LAMP assay developed for oak wilt takes 30 min to complete and shows 100% sensitivity and specificity. Recent studies have investigated colorimetric visualization of LAMP products for their adaptability to onsite microbial detection, but they suffer from reproducibility and varied perceptions of color change. Therefore, this study also discusses the development of a novel LAMP visualization method by exploiting the optical properties of gold nanoparticles (AuNPs) to overcome those challenges. Oligonucleotide-coated AuNPs (AuNP-oligos) hierarchically assemble on DNA networks in positive samples to form globular nanostructures, that settle into a visible red pellet upon inducing precipitation whereas, the negative samples do not show this. This LAMP assay coupled with AuNP-oligos visualization is a promising method for accurate and rapid molecular-based diagnosis in field settings.Additionally, other applications of nanomaterials in combating infectious diseases are also discussed. This includes the study of zinc oxide nanoparticle coated textiles for their antimicrobial activity against human bacterial and fungal pathogens, Pseudomonas aeruginosa, methicillin resistant Staphylococcus aureus, Klebsiella pneumoniae and Candida albicans.