ARTICLE pubs.acs.org/ac
Designed Hybridization Properties of DNAGold Nanoparticle Conjugates for the Ultraselective Detection of a Single-Base Mutation in the Breast Cancer Gene BRCA1 Ju-Hwan Oh and Jae-Seung Lee* Department of Materials Science and Engineering and Institute for Biomedical Research, Korea University, Anam-dong, Seongbuk-gu, Seoul, Republic of Korea, 136-713
bS Supporting Information ABSTRACT: We have investigated the hybridization properties of DNAgold nanoparticle conjugates and have discovered that the hybridization properties are dramatically affected by controlling various synthetic and environmental conditions. We have further demonstrated that moderate DNA loading instead of high loading per nanoparticle significantly enhances the hybridization rates of DNAgold nanoparticle conjugates, which allows one to precisely design their hybridization properties to distinguish a single-nucleotide polymorphism (SNP). A diagnostic application for the colorimetric detection of an SNP associated with a mutation in the breast cancer gene BRCA1 has been carefully designed and demonstrated.
D
NAgold nanoparticle conjugates (DNAAuNPs) have been investigated as one of the most fascinating nanomaterials owing to their unique chemical and physical properties.13 The development of how to precisely and reversibly control the assembly of spherical DNAAuNPs, combined with distantdependent optical properties and target-specific responses that are both quantitative and qualitative, has been utilized for a number of powerful and versatile diagnostic applications.4 For example, most of the disassembly-based detection schemes relying on either cooperative thermal denaturation of DNA duplexes57 or enzymatic cleavage of DNA linkages810 exhibit instantaneous nanoparticle dehybridization in response to target stimuli, resulting in a dramatic color change from purple or blue to red under specific conditions, which is used for quantitative measure. In contrast to the disassembly-based assays, assembly-based analyses inevitably depend on the hybridization of two complementary DNAAuNPs, which involves collisions between the nanoparticles followed by the random encounters of two complementary oligonucleotides. Because only a few nanoparticle collisions and DNADNA encounters would produce complete duplexes,11 however, the assembly formation of DNAAuNPs is often accompanied by slow kinetics and elongated assay times (typically several hours) compared with their disassembly (
