Cooperative dynamics of DNA-grafted magnetic nanoparticles optimize magnetic biosensing and coupling to DNA origami

Abstract

Magnetic nanoparticles (MNPs) open new opportunities for enzyme-free biosensing of nucleic acid biomarkers and magnetic actuation by patterning on DNA origami, yet how DNA grafting density affects their dynamics and...

Universal Click-Chemistry Approach for the DNA Functionalization of Nanoparticles

“…Finally, an assessment of our freezing-assisted SPAAC method in comparison to alternative reported methods for functionalization of nonmetallic particles, such as room-temperature mixing and salt aging, , shows that only the approach reported herein yields NPs that retain their stability under harsh salt and pH conditions. First, our comparative measurements of DNA (T22) functionalization of SiO 2 NPs indicate that freezing substantially increases the amount of conjugated DNA from 0.02 and 0.14 DNA/nm 2 for the mixing and salt aging method respectively to approximately 0.16–0.20 DNA/nm 2 for the freeze–thaw process (Figure S8a,b).…”

“…Recently, a click-chemistry reaction known as strain-promoted alkyne azide cycloaddition (SPAAC) has been increasingly explored as an alternative to thiols for DNA conjugation. − Not only does SPAAC benefit from very high specificity between dibenzylcyclooctyne (DBCO) and azide groups but it also works in both aqueous and organic solutions and does not require elevated temperatures, extreme pH conditions, or high salt concentrations . Furthermore, the reaction is not material-specific and can be applied to any type of NPs, as long as azide groups are present on the surface. , Similar to thiol functionalization, repulsion between azide-decorated NPs and DBCO–DNA strands can diminish the final DNA surface density and lead to long reaction times, something that is particularly limiting for biological applications .…”

“…Furthermore, the reaction is not material-specific and can be applied to any type of NPs, as long as azide groups are present on the surface. , Similar to thiol functionalization, repulsion between azide-decorated NPs and DBCO–DNA strands can diminish the final DNA surface density and lead to long reaction times, something that is particularly limiting for biological applications . However, to the best of our knowledge, little progress has been made toward overcoming this limitation, with only one report on the use of the salt aging method to electrostatically screen the NP and DNA reactive groups …”