Search

KR-102961903-B1 - Method for preparation of nanosnowman structure having long body

KR102961903B1KR 102961903 B1KR102961903 B1KR 102961903B1KR-102961903-B1

Abstract

The present invention relates to a method for manufacturing a nanosnowman structure comprising a head portion, a body portion with an increased aspect ratio, and a joint portion provided between the head portion and the body portion, and to the use thereof.

Inventors

  • 남좌민
  • 김지연
  • 김재명

Assignees

  • 서울대학교 산학협력단
  • 재단법인 바이오나노헬스가드연구단

Dates

Publication Date
20260512
Application Date
20220824

Claims (14)

  1. A first step of preparing gold nanoparticles whose surfaces are modified with oligonucleotides as a head portion; and A second step comprising reacting the gold nanoparticles modified with the above oligonucleotide with a reducing agent and a silver precursor in the presence of a polysorbate-based compound as a surfactant to form a body portion; A method for manufacturing a nanosnowman structure comprising a head portion, a body portion having an aspect ratio of 1.5 to 5.0, and a joint portion provided between the head portion and the body portion, A method for manufacturing a nanosnowman structure, wherein the thickness of the junction is controlled by controlling the type, number, or both of the nucleotides constituting the oligonucleotide.
  2. In paragraph 1, A method for manufacturing a nanosnowman structure, wherein the above-mentioned polysorbate-based compound is used at a concentration of 0.02 to 0.4% (w/v) based on the total volume of the reaction solution.
  3. In paragraph 1, A method for manufacturing a nano-snowman structure, wherein the long axis length, aspect ratio, or both of the body portion are controlled by controlling the concentration of the above-mentioned polysorbate-based compound.
  4. In paragraph 1, A method for manufacturing a nanosnowman structure, wherein the reducing agent comprises hydroquinone (HQ).
  5. In paragraph 1, A method for manufacturing a nanosnowman structure, wherein the above oligonucleotide comprises a combination of a total of 15 to 25 nucleotides, each composed of one or more nucleotides selected from the group consisting of thymine (T), cytosine (C), guanine (G), and adenine (A).
  6. delete
  7. In paragraph 1, A method for manufacturing a nanosnowman structure, wherein the head portion is based on a nanosphere with a diameter of 15 to 50 nm.
  8. In Paragraph 7, The above nanospheres with a diameter of 15 to 50 nm are Step 1-1: Preparing CTAB-capped seed particles with a diameter of 1 to 2 nm by adding sodium borohydride ( NaBH4 ) to a precursor solution containing cetyltrimethylammonium bromide (CTAB) and gold ions to reduce it; Step 1-2: preparing CTAC-capped gold nanospheres with a diameter of 7 to 12 nm by adding and reacting a precursor containing cetyltrimethylammonium chloride (CTAC), ascorbic acid (AA), and gold ions to the seed particles; and A method for manufacturing a nanosnowman structure, prepared through steps 1-3 of reacting a mixture of CTAC-capped gold nanospheres with a diameter of 7 to 12 nm with a precursor containing gold ions while adding the precursor.
  9. In paragraph 1, A method for manufacturing a nano-snowman structure, further comprising a third step of silica coating after the second step above.
  10. In paragraph 1, A method for manufacturing a nano-snowman structure, wherein the above-mentioned joint is formed of silver and is a cylindrical structure having a thickness less than or equal to the diameter of a head portion that is continuously connected to a body portion.
  11. A nanosnowman structure comprising: a head portion comprising gold nanospheres with a diameter of 15 to 50 nm modified with oligonucleotides on the surface; a body portion having an aspect ratio of 1.5 to 5.0 with a longest axis length of 25 to 150 nm; and a junction portion formed between the head portion and the body portion with a thickness less than or equal to the diameter of the head portion. A nanosnowman structure in which the thickness of the junction is controlled by controlling the type, number, or both of the nucleotides constituting the oligonucleotide.
  12. In Paragraph 11, A nano-snowman structure having a cylindrical structure formed of silver and continuously connected to a body part.
  13. In Paragraph 11, Nanosnowman structures that exhibit increased photoluminescence intensity compared to gold nanorods and organic dyes of the same length and thickness when excited by near-infrared light.
  14. A tissue imaging composition comprising the nanosnowman structure of claim 11 as an active ingredient.

Description

Method for preparation of nanosnowman structure having long body The present invention relates to a method for manufacturing a nanosnowman structure comprising a head portion, a body portion with an increased aspect ratio, and a joint portion provided between the head portion and the body portion, and to the use thereof. Direct photoluminescence (PL) from metals was first discovered in metal films and exhibited a low quantum yield (QY). Subsequently, the metal PL was enhanced using rough metal films, and PL from metal nanoparticles (NPs), including Au nanorods and Au nanocubes, is being studied based on localized surface plasmon resonance (LSPR). Plasmonically coupled nanostructures are known to increase the intensity and QY of PL from metal nanostructures. When Au NPs were placed on an Al₂O₃ -coated Au film, a distinct PL peak was observed near the gap-plasmon resonance wavelength. It has been reported that highly enhanced PL intensity and QY, which are distinctly stronger than those of Au nanorods (AuNRs) and attributed to superradiative plasmon modes, were observed from Au cube-in-cube nanostructures. Near-infrared (NIR) laser-based PL signals from metal NPs are advantageous for biomedical sensing and imaging applications due to the NIR window covering a wide wavelength range from 650 nm to 1350 nm and providing maximum penetration depth in tissues. Recently, it has been suggested that the PL of the AuNRs can be explained by hot carriers generated by interband and intraband transitions, leading to radiative recombination enhanced by the Purcell effect. Since the 785-nm wavelength is below the threshold for interband transitions in Au (1.7-1.8 eV), the PL of AuNRs from intraband transitions induced by a 785 nm laser resulted in a lower QY than the PL generated from both interband and intraband transitions by high-energy lasers. Therefore, the intensity and QY of the NIR-excited PL can be further enhanced to obtain stronger PL from the metal NPs. It is known that the PL from within-band transitions of Ag nanorods (AgNRs) has a QY similar to that of AuNRs from both between-band and within-band transitions, due to efficient transitions and low losses in Ag, which originate from the lower imaginary part of the dielectric function that induces lower non-radiative decay for Ag than for Au. Although AgNPs exhibit stronger optical properties, they are not widely used due to the relatively lower reduction potential of Ag compared to AuNPs, along with issues regarding oxidation and particle stability. Furthermore, synthesizing various forms of AgNPs, including elongated forms with LSPR in the NIR region, usually requires long reaction times and high temperatures. The PL of metal NPs can be used as label-free sensing probes because the optical signal is generated directly from their structure without any other modified dyes. Furthermore, the PL of said metal NPs possesses a photostable signal that is nonphotobleaching and nonphotoblinking. Therefore, the PL of metal NPs can be used in sensing and imaging applications as a robust optical label. In particular, NIR excitation and emission offer advantages such as deeper sample penetration based on reduced photon-scattering probability and low autofluorescence compared to shorter wavelengths. However, issues regarding low PL intensity and QY have not been resolved, failing to convincingly demonstrate the use of these direct PL signal-generating plasmonic nanoprobes for biomedical applications, particularly in the NIR region. PL metal nanostructures with high QY in the NIR region are promising for real-time/long-term imaging and monitoring applications, particularly for deep layers of highly scattering samples. Figure 1 shows the TWEEN20-mediated synthesis method and electron microscopy characterization results of Au-Ag LNS having DNA-engineered conductive nanobridges between the Au head and the long Ag body. (a) shows the synthetic scheme of Au-Ag LNS. (b) shows a large-area HAADF-STEM image of Au-Ag LNS. (c) shows a HAADF-STEM image of Au-Ag LNS. (d) shows an SEM image of Au-Ag LNS. (e) shows a HAADF-STEM image and corresponding EDX mapping. Red and green colors represent the elements Au and Ag, respectively. The scale bar is 50 nm. Figure 2 shows the absorption characteristics and morphology of Au-AgNS according to the type of surfactant and reaction time. (a) shows the extinction spectra of intermediates prepared by quenching the Ag growth reaction with mercaptopropanoic acid at 5 sec, 10 sec, 15 sec, 60 sec, and 10 min using TWEEN20 surfactant and (b) PVP surfactant, and (c) shows TEM images of intermediates prepared as above using TWEEN20 surfactant and (d) PVP surfactant. The scale bar is 50 nm. Figure 3 shows TEM images of Au-Ag LNSs obtained by adjusting the TWEEN20 concentration. The scale bar is 50 nm. Figure 4 shows the results of the optical analysis of Au-Ag LNS. (a) and (b) show the absorption spectra and PL spectra of Au-Ag LNS synthesized using various c