High performance UV photodetectors using Nd³⁺ and Er³⁺ single- and co-doped DNA thin films

Vellampatti, Srivithya,Reddeppa, Maddaka,Dugasani, Sreekantha Reddy,Mitta, Sekhar Babu,Gnapareddy, Bramaramba,Kim, Moon-Deock,Park, Sung Ha Elsevier 2019 Biosensors & bioelectronics Vol.126 No.-

<P><B>Abstract</B></P> <P>Even though lanthanide ion (Ln<SUP>3+</SUP>)-doped DNA nanostructures have been utilized in various applications, they are rarely employed for photovoltage generating devices because of difficulties in designing DNA-based devices that generate voltages under light illumination. Here, we constructed DNA lattices made of synthetic strands and DNA thin films extracted from salmon (SDNA) with single-doping of Nd<SUP>3+</SUP> or Er<SUP>3+</SUP> and co-doping of Nd<SUP>3+</SUP>/Er<SUP>3+</SUP> for high performance UV detection. The topological change of the DNA double-crossover (DX) lattices during the course of annealing was estimated from atomic force microscope (AFM) images to find the optimum concentration of Ln<SUP>3+</SUP> ([Ln<SUP>3+</SUP>]<SUB>O</SUB>). No topological disturbance in DNA DX lattices were observed up to [Ln<SUP>3+</SUP>]<SUB>O</SUB>, and significant enhancement in the physical properties was obtained at [Ln<SUP>3+</SUP>]<SUB>O</SUB>. The interactions between Ln<SUP>3+</SUP> and SDNA were examined using spectroscopic methods of UV–visible, Raman, and X-ray photoelectron spectroscopy (XPS). Current and photovoltage measurements for Ln<SUP>3+</SUP>-doped SDNA thin films under UV illumination with varying power intensities were conducted. Under UV illumination, the photocurrent and photovoltage of Ln<SUP>3+</SUP>-doped SDNA thin films increased with increasing applied external voltages and input power intensities, respectively. In addition, we observed considerable increases in photovoltage responses, <I>i.e.</I>, 5-fold increase for Nd<SUP>3+</SUP>, 10-fold for Er<SUP>3+</SUP>, and 13-fold for Nd<SUP>3+</SUP>/ Er<SUP>3+</SUP>, compared to the pristine SDNA due to the additional charge carriers generated in Ln<SUP>3+</SUP>-doped SDNA thin films. Device performance was measured in terms of photovoltage responsivity and retention characteristics. These phenomena indicate the high stability and substantial endurance characteristics of Ln<SUP>3+</SUP>-doped SDNA thin films.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ln<SUP>3+</SUP>-doped DNA thin films are rarely employed for photovoltage generating devices yet. </LI> <LI> We constructed DNA thin films with doping of Nd<SUP>3+</SUP> and Er<SUP>3+</SUP> for high performance UV detection. </LI> <LI> The interactions between Ln<SUP>3+</SUP> and DNA were examined using spectroscopic methods of UV–visible, Raman, and XPS. </LI> <LI> Under UV, the photocurrent and photovoltage of Ln<SUP>3+</SUP>-doped DNA thin films were varied with voltage and power, respectively. </LI> <LI> Ln<SUP>3+</SUP>-doped DNA thin films exhibited high stability and substantial endurance characteristics. </LI> </UL> </P>

Streptavidin bound DNA open tube and Zn²⁺-doped DNA open lattice

Vellampatti, S.,Mitta, S.B.,Kim, J.A.,Hwang, T.,Dugasani, S.R.,Kim, T.,Park, S.H. Elsevier 2015 CURRENT APPLIED PHYSICS Vol.15 No.8

DNA is one of the most promising molecules for use in nanotechnology because it has a nanoscale size and also has the ability for self-assembly. In this paper, we discuss the use of free-solution growth for a 1D DNA open tube (OT) and substrate-assisted growth for a 2D open lattice (OL), which can both achieve similar design schemes. We introduced biotinylated OT and OL, which can be bound with streptavidin for visualization, to verify via atomic force microscopy that dimensional structures have in fact been formed. Additionally the coverage ratio controlled by the concentration of the DNA monomer was analyzed to understand the lattice growth on the substrate. The DNA lattices were observed to start growing on the substrate at a concentration of around 1 nM (threshold) and to achieve full coverage at 10 nM (saturation concentration). Finally, the Raman spectra and the current-voltage characteristics of Zn<SUP>2+</SUP>-doped OLs were obtained in order to demonstrate the feasibility of using such methods to produce useful materials for nanodevices and biosensors. As [Zn<SUP>2+</SUP>] increases above the critical value of 0.5 mM, the Raman peaks gradually decrease. The resistance decreases up to the critical value of [Zn<SUP>2+</SUP>], and then decreases [Zn<SUP>2+</SUP>] continues to increase.

Streptavidin bound DNA open tube and Zn2+-doped DNA open lattice

Srivithya Vellampatti,Sekhar Babu Mitta,김장아,황태현,레디,김태성,박성하 한국물리학회 2015 Current Applied Physics Vol.15 No.8

DNA is one of the most promising molecules for use in nanotechnology because it has a nanoscale size and also has the ability for self-assembly. In this paper, we discuss the use of free-solution growth for a 1D DNA open tube (OT) and substrate-assisted growth for a 2D open lattice (OL), which can both achieve similar design schemes.We introduced biotinylated OT and OL, which can be bound with streptavidin for visualization, to verify via atomic force microscopy that dimensional structures have in fact been formed. Additionally the coverage ratio controlled by the concentration of the DNA monomer was analyzed to understand the lattice growth on the substrate. The DNA lattices were observed to start growing on the substrate at a concentration of around 1 nM (threshold) and to achieve full coverage at 10 nM (saturation concentration). Finally, the Raman spectra and the currentevoltage characteristics of Zn2+-doped OLs were obtained in order to demonstrate the feasibility of using such methods to produce useful materials for nanodevices and biosensors. As [Zn2+] increases above the critical value of 0.5 mM, the Raman peaks gradually decrease. The resistance decreases up to the critical value of [Zn2+], and then decreases [Zn2+] continues to increase.

Aptamer-conjugated DNA nano-ring as the carrier of drug molecules

Srivithya, Vellampatti,Roun, Heo,Sekhar Babu, Mitta,Jae Hyung, Park,Sung Ha, Park IOP 2018 Nanotechnology Vol.29 No.9

<P>Due to its predictable self-assembly and structural stability, structural DNA nanotechnology is considered one of the main interdisciplinary subjects encompassing conventional nanotechnology and biotechnology. Here we have fabricated the mucin aptamer (MUC1)˗conjugated DNA nano˗ring intercalated with doxorubicin (DNR<SUB>A</SUB>˗DOX) as potential therapeutics for breast cancer. DNR<SUB>A</SUB>˗DOX exhibited significantly higher cytotoxicity to the MCF˗7 breast cancer cells than the controls, including DOX alone and the aptamer deficient DNA nano˗ring (DNR) with doxorubicin. Interactions between DOX and DNR<SUB>A</SUB> were studied using spectrophotometric measurements. Dose-dependent cytotoxicity was performed to prove that both DNR and DNR<SUB>A</SUB> were non-toxic to the cells. The drug release profile showed a controlled release of DOX at normal physiological pH 7.4, with approximately 61% released, but when exposed to lysosomal of pH 5.5, the corresponding 95% was released within 48 h. Owing to the presence of the aptamer, DNR<SUB>A</SUB>˗DOX was effectively taken up by the cancer cells, as confirmed by confocal microscopy, implying that it has potential for use in targeted drug delivery.</P>

Gold nanoparticle-embedded DNA thin films for ultraviolet photodetectors

Mitta, Sekhar Babu,Reddeppa, Maddaka,Vellampatti, Srivithya,Dugasani, Sreekantha Reddy,Yoo, Sanghyun,Lee, Seungwoo,Kim, Moon-Deock,Ha Park, Sung Elsevier 2018 Sensors and actuators. B Chemical Vol.275 No.-

<P><B>Abstract</B></P> <P>Although DNA (low-cost, highly transparent, low optical loss, biodegradable, non-toxic, and highly flexible) and gold nanoparticles (Au NPs, exhibiting interband transition and localized surface plasmon resonance) have been intensively studied, DNA with Au NPs in photodetectors is rarely discussed. Here, we constructed salmon DNA (SDNA) thin films and incorporated Au NPs to demonstrate efficient and high-performance UV photodetectors. The Au NP-embedded SDNA thin films were characterized with UV–vis absorption, Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and conductivity measurements in order to understand their physical and chemical properties. The FTIR and XPS measurements elucidated how Au NPs become embedded in SDNA, through analysis of chemical binding and chemical composition. A current increase was observed under UV illumination when performing conductivity measurements. In addition, photovoltage measurements were conducted to investigate the significance of photoresponse and retention characteristics. The density of <I>d</I>-band electrons in Au NPs and the charge carriers in SDNA were observed to increase under UV illumination, followed by a significantly enhanced UV photoresponse. From our observations, the photovoltage displayed a flat response over time, which indicated their stability, durability, and high Au NP retention.</P> <P><B>Highlights</B></P> <P> <UL> <LI> DNA thin films incorporated with Au NPs are fabricated to demonstrate efficient and high-performance UV photodetectors. </LI> <LI> The Au NP-embedded SDNA thin films are characterized in order to understand their physical and chemical properties. </LI> <LI> The FTIR and XPS elucidate how Au NPs become embedded in SDNA,through analysis of chemical binding and chemical composition. </LI> <LI> Photovoltage measurements are conducted to investigate the significance of photoresponse and retention characteristics. </LI> <LI> Photovoltage response indicates the stability, durability, and high Au NP retention. </LI> </UL> </P>

Electromagnetic and optical characteristics of Nb⁵⁺-doped double-crossover and salmon DNA thin films

Mitta, Sekhar Babu,Dugasani, Sreekantha Reddy,Jung, Soon-Gil,Vellampatti, Srivithya,Park, Tuson,Park, Sung Ha IOP 2017 Nanotechnology Vol.28 No.40

<P>We report the fabrication and physical characteristics of niobium ion (Nb<SUP>5+</SUP>)-doped double-crossover DNA (DX-DNA) and salmon DNA (SDNA) thin films. Different concentrations of Nb<SUP>5+</SUP> ([Nb<SUP>5+</SUP>]) are coordinated into the DNA molecules, and the thin films are fabricated via substrate-assisted growth (DX-DNA) and drop-casting (SDNA) on oxygen plasma treated substrates. We conducted atomic force microscopy to estimate the optimum concentration of Nb<SUP>5+</SUP> ([Nb<SUP>5+</SUP>]<SUB>O</SUB>?=?0.08 mM) in Nb<SUP>5+</SUP>-doped DX-DNA thin films, up to which the DX-DNA lattices maintain their structures without deformation. X-ray photoelectron spectroscopy (XPS) was performed to probe the chemical nature of the intercalated Nb<SUP>5+</SUP> in the SDNA thin films. The change in peak intensities and the shift in binding energy were witnessed in XPS spectra to explicate the binding and charge transfer mechanisms between Nb<SUP>5+</SUP> and SDNA molecules. UV-visible, Raman, and photoluminescence (PL) spectra were measured to determine the optical properties and thus investigate the binding modes, Nb<SUP>5+</SUP> coordination sites in Nb<SUP>5+</SUP>-doped SDNA thin films, and energy transfer mechanisms, respectively. As [Nb<SUP>5+</SUP>] increases, the absorbance peak intensities monotonically increase until ∼[Nb<SUP>5+</SUP>]<SUB>O</SUB> and then decrease. However, from the Raman measurements, the peak intensities gradually decrease with an increase in [Nb<SUP>5+</SUP>] to reveal the binding mechanism and binding sites of metal ions in the SDNA molecules. From the PL, we observe the emission intensities to reduce them at up to ∼[Nb<SUP>5+</SUP>]<SUB>O</SUB> and then increase after that, expecting the energy transfer between the Nb<SUP>5+</SUP> and SDNA molecules. The current–voltage measurement shows a significant increase in the current observed as [Nb<SUP>5+</SUP>] increases in the SDNA thin films when compared to that of pristine SDNA thin films. Finally, we investigate the temperature dependent magnetization in which the Nb<SUP>5+</SUP>-doped SDNA thin films reveal weak ferromagnetism due to the existence of tiny magnetic dipoles in the Nb<SUP>5+</SUP>-doped SDNA complex.</P>

Coverage percentage and raman measurement of cross-tile and scaffold cross-tile based DNA nanostructures

Gnapareddy, Bramaramba,Ahn, Sang Jung,Dugasani, Sreekantha Reddy,Kim, Jang Ah,Amin, Rashid,Mitta, Sekhar Babu,Vellampatti, Srivithya,Kim, Byeonghoon,Kulkarni, Atul,Kim, Taesung,Yun, Kyusik,LaBean, Tho Elsevier 2015 Colloids and Surfaces B Vol.135 No.-

<P><B>Abstract</B></P> <P>We present two free-solution annealed DNA nanostructures consisting of either cross-tile CT1 or CT2. The proposed nanostructures exhibit two distinct structural morphologies, with one-dimensional (1D) nanotubes for CT1 and 2D nanolattices for CT2. When we perform mica-assisted growth annealing with CT1, a dramatic dimensional change occurs where the 1D nanotubes transform into 2D nanolattices due to the presence of the substrate. We assessed the coverage percentage of the 2D nanolattices grown on the mica substrate with CT1 and CT2 as a function of the concentration of the DNA monomer. Furthermore, we fabricated a scaffold cross-tile (SCT), which is a new design of a modified cross-tile that consists of four four-arm junctions with a square aspect ratio. For SCT, eight oligonucleotides are designed in such a way that adjacent strands with sticky ends can produce continuous arms in both the horizontal and vertical directions. The SCT was fabricated <I>via</I> free-solution annealing, and self-assembled SCT produces 2D nanolattices with periodic square cavities. All structures were observed <I>via</I> atomic force microscopy. Finally, we fabricated divalent nickel ion (Ni<SUP>2+</SUP>)- and trivalent dysprosium ion (Dy<SUP>3+</SUP>)-modified 2D nanolattices constructed with CT2 on a quartz substrate, and the ion coordinations were examined <I>via</I> Raman spectroscopy.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We present free-solution annealed DNA nanotubes and DNA nanolattices consisting of cross-tiles (CT1 and CT2) and a scaffold cross-tile (SCT). </LI> <LI> When we perform mica-assisted growth annealing with CT1, a dimensional change occurs where the 1D nanotubes transform into 2D nanolattices. </LI> <LI> We assessed the coverage percentage of the 2D nanolattices grown on the mica substrate as a function of the DNA concentration. </LI> <LI> Finally, we fabricated divalent and trivalent ion-modified 2D nanolattices which were examined via Raman spectroscopy. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>