DNA Integration with Silver and Gold Nanoparticles: Enhancement of DNA Optical Anisotropy

Abstract

DNA integration with silver and gold nanoparticles was carried out by the chemical reduction of silver and gold ions after the formation of their complexes with high molecular DNA in solution. It is shown that, for a good association of DNA with nanoparticles, the ions of silver and gold should be linked with DNA bases rather strongly. The proposed model of gold interaction with DNA is the coordination of gold to N7 guanine in a major groove followed by the transformation of the GC pair to Hoogsteen’s type pairing, in which the gold atom is located between the bases and is bonded simultaneously to N7 guanine and N3 cytosine. For gold and silver nanoparticles associated with DNA, the peak of plasmon resonance shifts relative to that of free nanoparticles in solution. AFM (atomic force microscopy) images of both free and associated with DNA nanoparticles were obtained. Binding of high molecular DNA to gold and silver nanoparticles leads to a decrease in the size of its molecular coil in solution, but the bending rigidity of DNA helix (persistent length) does not change. The almost 3-fold increase in the optical anisotropy of DNA was observed when DNA was associated with gold nanoparticles. This result was obtained with the flow birefringence method using a light source with a wavelength of 550 nm, which is close to the peak of the plasmon resonance of gold nanoparticles. For DNA associated with silver nanoparticles, a similar result was obtained when using a light source with a wavelength of about 410 nm.

Ultrasensitive Dual-Signal Detection of Telomerase and MiR-21 Based on Boolean Logic Operations

“…DNA2-Ag (Figure E) with an average diameter of around 10 nm was observed by TEM. Through the UV spectra (Figure F), the two characteristic peaks that appeared in curve b indicated that we obtained DNA2-Ag, which were consistent with previous reports. , …”

“…Through the UV spectra (Figure 1F), the two characteristic peaks that appeared in curve b indicated that we obtained DNA2-Ag, which were consistent with previous reports. 40,41 Release of DNA3-ROX in Automatic Cascade Operations. To investigate whether DNA3 hairpins could be successfully released in a cascade reaction in the existence of telomerase and dNTPs, we had encapsulated DNA3-ROX in FOMNs (Scheme 1A).…”

Packaging of DNA Integrated with Metal Nanoparticles in Solution

“…We used the same procedures for preparing the silver and gold nanoparticles as described in articles [7,28]. The following composition of reagents was used for the synthesis of palladium nanoparticles in solution: the concentration of K 2 PdCl 4 was [K 2 PdCl 4 ] = 0.25 mM, and the concentration of reducing agent NaBH 4 was 1.5 mM.…”

Bottom-Up Fabrication of DNA-Templated Electronic Nanomaterials and Their Characterization

“…This technique of DNA metallization might find use in the DNA-assisted fabrication of nanostructures. Kasyanenko et al [ 79 ] demonstrated the formation of complexes with nitrogen bases on DNA by using Ag + and Au 3+ , and reduced these ions into Ag NPs (2–10 nm) and Au NPs (3–6 nm), but the NPs were not constructed into NWs. Ganguly et al [ 53 ] incorporated borane phosphate DNA onto CNTs; when Ag + , Au 3+ , or Pd 2+ was incubated with the constructs they were reduced into NPs because of the incorporated reducing equivalents.…”