Polyvalent Non-thiolated DNA Functionalized Gold Nanoparticles

Background

The last 16 years have witnessed the landmark development of polyvalent thiolated DNA functionalized gold nanoparticles (AuNPs) possessing striking properties within the emerging field of nanobiotechnology. Many novel properties of this hybrid nanomaterial are attributed to the dense DNA shell. However, the question of whether non-thiolated polyvalent DNA-AuNP could be fabricated with similar properties as its thiolated counterpart has not been addressed. This is due to a lack of fundamental understanding of DNA/AuNP interactions and the inherit challenges in applying the well-established salt-aging method to prepare such materials.

Description of the Invention

This technology describes a method for tuning the pH of the DNA/AuNP mixture, an ultrahigh capacity of non-thiolated DNA loading can be achieved in a few minutes, resulting in polyvalent DNA-AuNP conjugates with cooperative melting behavior, a typical property for polyvalent thiolated DNA functionalized AuNPs. With this method, large AuNPs (e.g., 50 nm) can be functionalized to achieve colorimetric detection of sub-nM DNA. Further, this fast and stable DNA loading was employed to separate AuNPs of different size. This discovery not only offers a time- and cost-effective way to functionalize AuNPs with a high density of non-thiolated DNA, but also provides new insights into the fundamental understanding of how DNA strands with different sequences interact with AuNP surfaces.

Advantages

A new material that achieves similar functions for biomarkers but uses non-thiolated DNA that can reduce the cost of DNA synthesis by more than 80%. In addition, the preparation procedure is much more time-saving, taking only 5-30 min in contrast to the thiolated method, which takes about 24 hours or more to prepare the thiol DNA functionalized gold nanoparticles.

Potential Applications

Such non-thiolated DNA-functionalized gold nanoparticles will present one of the primary materials in bioanalytical chemistry, biomarkers. The reported biomarker market has grown, from $5.5 billion in 2007 to $12.4 billion in 2012 (BusinessInsights). Cancer, cardiovascular, and pathogen biomarkers are currently each worth around $1.6 billion.