Biopebbles: DNA‐Functionalized Core–Shell Silica Nanospheres for Cellular Uptake and Cell Guidance Studies

Abstract

The development of a versatile class of silica nanoparticles for cell studies is reported. The particles contain a fluorescent dye-encoded core and a single-stranded DNA oligonucleotide-displaying shell. They are accessible in arbitrary size and color through robust protocols for Stöber-based colloidal synthesis and sturdy chemical surface functionalization. Silica particles in the size range of 100 nm to 1.5 µm diameter containing fluorescein, Cy3 oder Cy5 dye-encoded cores are synthesized and functionalized with DNA oligonucleotides. These silica biopebbles are conveniently traceable by microscopy and have a high affinity to live cells, which makes them ideal for cell uptake studies, as demonstrated for MCF7 and A431 cancer cells. The biopebbles can be utilized as building blocks for the self-assembled formation of arbitrary surface patterns on glass substrates. With these architectures, the privileged internalization of the biopebbles can be exploited for improved adhesion and guidance of cells because the particles are no longer ingested by adhered cells due to their physical connection with the solid support. It is believed that the biopebble approach will be useful for a variety of applications, fundamental studies in cell biology and tissue engineering.

Random access DNA memory in a scalable, archival file storage system

“…DNA hybridization assay was used to estimate the number of surface-accessible DNA barcodes [9][10][11] . In a typical experiment, we add 1 µL of 500 µM of TYE705-modified single-stranded DNA probe to a 1.5 mL Eppendorf LoBind tube that contains 50 µL of 2 mg mL -1 of files that has surface-attached barcodes that are complementary to the TYE705-modified DNA probe sequence.…”

Bottom‐Up Assembly of DNA–Silica Nanocomposites into Micrometer‐Sized Hollow Spheres

“…We initially investigated whether DNA‐SiNPs can be converted into polymer composites using the C‐HCR. To this end, zwitterion‐stabilized SiNPs of 80 nm diameter bearing poly(ethylene glycol) (PEG) chains in addition to amino, phosphonate, and thiol functional groups were synthesized by hydrolysis of silanes in a microemulsion system as previously described (see the Supporting Information, Figure S1), and functionalized with the aminoalkyl‐modified 44‐mer single‐stranded DNA (ssDNA) oligomer Ih by glutardialdehyde crosslinking (Figure ; for DNA sequences, see Table S1 in the Supporting Information). The about 100 Ih molecules per SiNP‐Ih (Table S2) serve as initiators that trigger the self‐assembly of the hairpin strands h1 , h2 and H1 , H2 to initiate gelation of the DNA‐SiNP composite material (Figure ).…”

“…The dispersed aqueous phase contained SiNP‐Ih particles that were prepolymerized by h1 / h2 ‐mediated linear HCR, as described above, in addition to the H1 and H2 hairpin strands. To enable visualization of the droplets by fluorescence microscopy, the DOTAP was doped with 1,2‐dimyristoyl‐ sn ‐glycero‐3‐phosphoethanolamine‐ N ‐(lissamine rhodamine B sulfonyl) (Rh‐PE) lipid (0.1 mol %, green in Figure ), and the SiNPs were labeled with the fluorescent dye Cy5 (red in Figure ) by a previously reported method …”

DNA Surface Technology: From Gene Sensors to Integrated Systems for Life and Materials Sciences

“…In as imilar way,t emplate-confined, DNA-mediated nanoparticle assembly was used to prepare physically and spectrally encrypted surface patterns. [42] Since other nanoparticles,s uch as semiconductor quantum dots, [43] CNTs, [44] or silica nanoparticles (SiNPs), [45] are also accessible for the DDI approach, there are many possibilities to use DNA-modified surfaces for materials research as well as for the life sciences.F or example,s elf-assembled 2D micropatterns of oligonucleotide-functionalized, dye-encoded core/ shell SiNPs on glass substrates have been used for improved adhesion and guidance of eukaryotic cells ( Figure 4A). [42] Since other nanoparticles,s uch as semiconductor quantum dots, [43] CNTs, [44] or silica nanoparticles (SiNPs), [45] are also accessible for the DDI approach, there are many possibilities to use DNA-modified surfaces for materials research as well as for the life sciences.F or example,s elf-assembled 2D micropatterns of oligonucleotide-functionalized, dye-encoded core/ shell SiNPs on glass substrates have been used for improved adhesion and guidance of eukaryotic cells ( Figure 4A).…”

“…[41] Furthermore,D NA surfaces can generally be used for preparative measures,f or example,t oa ssemble nanoparticle superstructures on surfaces in the sense of as olid-phase synthesis,topurify them, and then to cleave and isolate them for further characterization and applications. [45] 5. [45] 5.…”