Mild Two-Step Method to Construct DNA-Conjugated Silicon Nanoparticles: Scaffolds for the Detection of MicroRNA-21

Abstract

We describe a novel two-step method, starting from bulk silicon wafers, to construct DNA conjugated silicon nanoparticles (SiNPs). This method first utilizes reactive high-energy ball milling (RHEBM) to obtain alkene grafted SiNPs. The alkene moieties are subsequently reacted with commercially available thiol-functionalized DNA via thiol–ene click chemistry to produce SiNP DNA conjugates wherein the DNA is attached through a covalent thioether bond. Further, to show the utility of this synthetic strategy, we illustrate how these SiNP ODN conjugates can detect cancer-associated miR-21 via a fluorescence ON strategy. Given that an array of biological molecules can be prepared with thiol termini and that SiNPs are biocompatible and biodegradable, we envision that this synthetic protocol will find utility in salient SiNP systems for potential therapeutic and diagnostic applications.

Ion‐Tagged Oligonucleotides Coupled with a Magnetic Liquid Support for the Sequence‐Specific Capture of DNA

“…LC‐TOFMS, densitometry, and HPLC revealed 40–45 % and 51–53 % yields for the [ABIM + ] and [AOIM + ]‐ITOs, respectively (Figures S6–S10, Table S2, and the Supporting Information for details). The yields reported in the present study are the highest ever achieved for the radical coupling of a thiolated oligonucleotide and alkene substrate …”

Metal‐Free Click Chemistry Reactions on Surfaces

“…Very recently, Su et al used this click reaction for the construction of DNA conjugated Si NPs with potential application as fluorescence ON sensors for the detection of noncoding RNA involved in a variety of cancers ( Figure ) . The reaction between alkene‐terminated NPs and thiol‐terminated fluorescein‐labeled DNA was conducted in DMSO (365 nm, DMPA) and after 30 min, an efficient coupling was obtained, according to the significant increase of the diameter obtained by transmission electron microscopy (TEM) of the conjugated Si NPs (10 nm) compared to that of the unconjugated Si NPs (3 nm).…”

“…Functionalization of silicon NPs using TEC chemistry to yield a fluoresence ON‐OFF mechanism for ds‐DNA hybridization …”

Ion‐Tagged Oligonucleotides Coupled with a Magnetic Liquid Support for the Sequence‐Specific Capture of DNA

“…Following PAGE, bands were excised, eluted in water overnight, and analyzed by liquid chromatography time-of-flight mass spectrometry (LC-TOFMS,s ee the Supporting Information for details). [24,25] To study the influence of the ion tag on hybridization, melting point (T m )a nalysis was conducted for the 15-mer ITOs with complementary strands.W hile the [AMIM + ]a nd [ABIM + ]-ITOss howed no difference in T m compared to an unmodified 15-mer (Supporting Information, Figure S11), as light decrease in T m for the [AOIM + ]-ITO and its complement was observed. LC-TOFMS,d ensitometry,a nd HPLC revealed 40-45 %a nd 51-53 %y ields for the [ABIM + ]a nd [AOIM + ]-ITOs,r espectively (Figures S6-S10, Table S2, and the Supporting Information for details).…”

“…They ields reported in the present study are the highest ever achieved for the radical coupling of at hiolated oligonucleotide and alkene substrate. [24,25] To study the influence of the ion tag on hybridization, melting point (T m )a nalysis was conducted for the 15-mer ITOs with complementary strands.W hile the [AMIM + ]a nd [ABIM + ]-ITOss howed no difference in T m compared to an unmodified 15-mer (Supporting Information, Figure S11 Thepartitioning of ITOs into ahydrophobic MIL support was investigated to determine the ITO probe that would best facilitate sequence-specific DNAe xtraction. Thet rihexyl(tetradecyl)phosphonium manganese(II) hexafluoroacetylacetonate ([P 66 614 + ][Mn(hfacac) 3 À ]) MIL was selected as the magnetic liquid support because of its hydrophobicity,l ow viscosity,a nd paramagnetic susceptibility (synthesis in the Supporting Information).…”