Thesis Type: Postgraduate
Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Arts and Sciences, Department of Biology, Turkey
Approval Date: 2017
Student: MÜSLÜM KAAN ARICI
Co-Supervisor: HÜSEYİN AVNİ ÖKTEM, AYŞE MERAL YÜCEL
Abstract:Advances in nanomaterials have promoted the development of biosensor technologies. User friendly, fast, economic, reliable biosensors can be incorporated into diagnostic methods. Without complex laboratory equipment and qualified person, Point of Care (PoC) tests with biosensors can be carried out. Among a variety of biosensors, nucleic acid based biosensors are promising to have high specificity and sensitivity. Thus, in this study, nucleic acids are employed on modifications of nanomaterials during construction of lateral flow assay (LFA) platform. Foodborne diseases continue to be a major health issue. A major reason of foodborne disease is Salmonella contamination. Contaminated foods give rise to serious illnesses, possibly hospitalization and death if untreated. Consequently; safe, rapid and economic detection methods of Salmonella is likely to improve public health. The aim of this study is detection of Salmonella with LFA including mesoporous silica nanoparticles (MSP-SiNPs). In this study, MSP-SiNPs, entrapping 3,3’,5,5’-Tetramethylbenzidine (TMB), were functionalized with oligonucleotide probes, which were complementary sequences to InvA gene of Salmonella. Complementary target sequence took oligonucleotides away from SiNPs and made TMB released so that HRP-H2O2 can oxidize TMB. Optimization experiments were carried out to get proper colorimetric reaction on LFA,. In our study, optimized LFA platform could manage high specificity. 284 bp amplicon of InvA gene and 292 bp amplicon of Ycdt gene were significantly discriminated by complementary probes. Probes could considerably differentiate targets and 3 mismatches on complementary sequences. Sensitivity of SiNPs based LFA was also checked with synthetic targets and PCR. Limit of Detection (LoD) for synthetic complementary target reached up to l5 nM. LoD for PCR was found at 15 cycle. SiNPs based LFA system, advanced in this study, achieved to specifically and sensitively detect Salmonella through target amplicon. The device is promising, hopeful and up-coming for undeveloped countries to do a field study. SiNPs based LFA is a cheap, rapid, reliable and user-friendly detection system.