Structural stability and electrical characteristic of DNA lattices doped with lanthanide ions

Dugasani, S.R.,Gnapareddy, B.,Kim, J.A.,Yoo, S.,Hwang, T.,Kim, T.,Park, S.H. ELSEVIER 2017 CURRENT APPLIED PHYSICS Vol.17 No.11

<P>The main aim of doping DNA lattices with lanthanide ions (Ln-DNA complex) is to change the physical functionalities for specific target applications such as electronics and biophotonics. Ln-DNA complexes based on a double-crossover DNA building block were fabricated on glass using a substrate-assisted growth method. We demonstrated the structural stability of Ln-DNA complexes as a function of Ln ion concentration by the atomic force microscopy. The Ln ion doping in DNA lattices was examined using a chemical reduction process, and the electrical characteristics of Ln-DNA complexes were tested using a semiconductor parameter analyzer. The structural phase transition of DNA lattices from the crystalline to amorphous phases occurred at a certain critical concentration of each Ln ion. Ln ions in DNA lattices are known to be intercalated between the base pairs and bound with phosphate backbones. When DNA lattices are properly doped with Ln ions, Ln-DNA complexes revealed the complete deformation with chemical reduction process by ascorbic acid. The current increased up to a critical Ln ion concentration and then decreased with further increasing Ln ions. Ln-DNA complexes will be useful in electronics and photonics because of their unique physical characteristics. (C) 2017 Elsevier B.V. All rights reserved.</P>

Metal electrode dependent field effect transistors made of lanthanide ion-doped DNA crystals

Dugasani, Sreekantha Reddy,Hwang, Taehyun,Kim, Jang Ah,Gnapareddy, Bramaramba,Kim, Taesung,Park, Sung Ha IOP 2016 Journal of Physics. D, Applied Physics Vol.49 No.10

<P>We fabricated lanthanide ion (Ln<SUP>3+</SUP>, e.g. Dy<SUP>3+</SUP>, Er<SUP>3+</SUP>, Eu<SUP>3+</SUP>, and Gd<SUP>3+</SUP>)-doped self-assembled double-crossover (DX) DNA crystals grown on the surface of field effect transistors (FETs) containing either a Cr, Au, or Ni electrode. Here we demonstrate the metal electrode dependent FET characteristics as a function of various Ln<SUP>3+</SUP>. The drain–source current (<I>I</I> <SUB>ds</SUB>), controlled by the drain–source voltage (<I>V</I> <SUB>ds</SUB>) of Ln<SUP>3+</SUP>-doped DX DNA crystals with a Cr electrode on an FET, changed significantly under various gate voltages (<I>V</I> <SUB>g</SUB>) due to the relative closeness of the work function of Cr to the energy band gap of Ln<SUP>3+</SUP>-DNA crystals compared to those of Au and Ni. For Ln<SUP>3+</SUP>-DNA crystals on an FET with either a Cr or Ni electrode at a fixed <I>V</I> <SUB>ds</SUB>, <I>I</I> <SUB>ds</SUB> decreased with increasing <I>V</I> <SUB>g</SUB> ranging from  −2 to 0 V and from 0 to  +3 V in the positive and negative regions, respectively. By contrast, <I>I</I> <SUB>ds</SUB> for Ln<SUP>3+</SUP>-DNA crystals on an FET with Au decreased with increasing <I>V</I> <SUB>g</SUB> in only the positive region due to the greater electronegativity of Au. Furthermore, Ln<SUP>3+</SUP>-DNA crystals on an FET exhibited behaviour sensitive to <I>V</I> <SUB>g</SUB> due to the appreciable charge carriers generated from Ln<SUP>3+</SUP>. Finally, we address the resistivity and the mobility of Ln<SUP>3+</SUP>-DNA crystals on an FET with different metal electrodes obtained from <I>I</I> <SUB>ds</SUB>–<I>V</I> <SUB>ds</SUB> and <I>I</I> <SUB>ds</SUB>–<I>V</I> <SUB>g</SUB> curves. The resistivities of Ln<SUP>3+</SUP>-DNA crystals on FETs with Cr and Au electrodes were smaller than those of pristine DNA crystals on an FET, and the mobility of Ln<SUP>3+</SUP>-DNA crystals on an FET with Cr was relatively higher than that associated with other electrodes.</P>

Optical Band Gap and Hall Transport Characteristics of Lanthanide-Ion-Modified DNA Crystals

Dugasani, Sreekantha Reddy,Ha, Taewoo,Kim, Si Joon,Gnapareddy, Bramaramba,Yoo, Sanghyun,Lee, Keun Woo,Jung, Tae Soo,Kim, Hyun Jae,Park, Sung Ha,Kim, Jae Hoon American Chemical Society 2015 The Journal of Physical Chemistry Part C Vol.119 No.25

<P>Lanthanide-ion-modified DNA crystals are fabricated on quartz and silica substrates via surface-assisted growth, and the optical band gap and electrical Hall transport are measured at room temperature for these crystals. The optical band gap of these crystals shows an increasing behavior, and the second band onset showed the inverted V shape upon increasing the lanthanide ion concentration. At a particular concentration, each lanthanide ion into the DNA crystals exhibited low resistivity, low Hall mobility, high free carrier concentration, and a minimum magneto resistance. The experimental results show feasibility in controlling important physical parameters, such as the band gap energy and Hall parameters, by adjusting the concentration of the lanthanide ion. When combined with the existing structural versatility of DNA nanostructures, these functional tunabilities will be crucial for the future development of DNA-based nanoelectronic and biophotonic devices.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2015/jpccck.2015.119.issue-25/acs.jpcc.5b03875/production/images/medium/jp-2015-03875a_0003.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp5b03875'>ACS Electronic Supporting Info</A></P>

Hall transport of divalent metal ion modified DNA lattices

Dugasani, Sreekantha Reddy,Lee, Keun Woo,Kim, Si Joon,Yoo, Sanghyun,Gnapareddy, Bramaramba,Jung, Joohye,Jung, Tae Soo,Bashar, Saima,Kim, Hyun Jae,Park, Sung Ha American Institute of Physics 2015 Applied Physics Letters Vol.106 No.26

Energy Band Gap and Optical Transition of Metal Ion Modified Double Crossover DNA Lattices

Dugasani, Sreekantha Reddy,Ha, Taewoo,Gnapareddy, Bramaramba,Choi, Kyujin,Lee, Junwye,Kim, Byeonghoon,Kim, Jae Hoon,Park, Sung Ha American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.20

<P>We report on the energy band gap and optical transition of a series of divalent metal ion (Cu<SUP>2+</SUP>, Ni<SUP>2+</SUP>, Zn<SUP>2+</SUP>, and Co<SUP>2+</SUP>) modified DNA (M–DNA) double crossover (DX) lattices fabricated on fused silica by the substrate-assisted growth (SAG) method. We demonstrate how the degree of coverage of the DX lattices is influenced by the DX monomer concentration and also analyze the band gaps of the M–DNA lattices. The energy band gap of the M–DNA, between the lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO), ranges from 4.67 to 4.98 eV as judged by optical transitions. Relative to the band gap of a pristine DNA molecule (4.69 eV), the band gap of the M–DNA lattices increases with metal ion doping up to a critical concentration and then decreases with further doping. Interestingly, except for the case of Ni<SUP>2+</SUP>, the onset of the second absorption band shifts to a lower energy until a critical concentration and then shifts to a higher energy with further increasing the metal ion concentration, which is consistent with the evolution of electrical transport characteristics. Our results show that controllable metal ion doping is an effective method to tune the band gap energy of DNA-based nanostructures.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-20/am503614x/production/images/medium/am-2014-03614x_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am503614x'>ACS Electronic Supporting Info</A></P>

Tailoring chemical and physical properties of graphene-added DNA hybrid thin films

Dugasani, Sreekantha Reddy,Gnapareddy, Bramaramba,Mitta, Sekhar Babu,Park, Sung Ha ELSEVIER 2019 CURRENT APPLIED PHYSICS Vol.19 No.3

<P><B>Abstract</B></P> <P>While the characteristics of DNA and graphene are well studied, the chemical and physical properties of graphene-embedded DNA and cetyltrimethyl-ammonium chloride-modified DNA (CT-DNA) hybrid thin films (HTFs) have been rarely discussed due to the limited development of fabrication methodologies. Herein, we developed a simple drop-casting method for constructing DNA and CT-DNA HTFs added with graphene nanopowder (GNP). Additionally, we demonstrated their distinct characteristics, such as their structure, elemental composition, spin states and chemical functional groups, binding interactions, vibration/stretching modes by UV–Vis absorption, PL, and electrical measurements. The EDS spectra of GNP-added DNA HTFs showed C, N, O, Na, and P peaks at characteristic energies. Because of the physical adsorption of GNP on DNA, the peak shifts and suppression of the core spectra of O 1s and P 2p were observed by XPS. The intensity variation of Raman and FTIR bands indicated hybrid formation of GNP in DNA and CT-DNA through adsorption, electrostatic interaction, and π–π stacking. UV–Vis absorption and PL spectra showed the considerable influence of GNP in DNA and CT-DNA HTFs. DNA and CT-DNA HTFs with relatively higher [GNP] showed significant increases of current due to the formation of interconnected networks of GNP in the DNA and CT-DNA HTFs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> DNA and CTMA-DNA thin films with graphene are constructed by a drop-casting. </LI> <LI> Distinct characteristics of DNA and CTMA-DNA thin films with graphene are studied. </LI> <LI> The significance of optical spectroscopy and PL characteristics are discussed. </LI> <LI> Applications of DNA and CTMA-DNA thin films are addressed. </LI> </UL> </P>

Magnetic studies of Co²⁺, Ni²⁺, and Zn²⁺−modified DNA double−crossover lattices

Dugasani, Sreekantha Reddy,Oh, Young Hoon,Gnapareddy, Bramaramba,Park, Tuson,Kang, Won Nam,Park, Sung Ha Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.427 No.1

<P><B>Abstract</B></P> <P>We fabricated divalent-metal-ion-modified DNA double-crossover (DX) lattices on a glass substrate and studied their magnetic characteristics as a function of ion concentrations [Co<SUP>2+</SUP>], [Ni<SUP>2+</SUP>] and [Zn<SUP>2+</SUP>]. Up to certain critical concentrations, the DNA DX lattices with ions revealed discrete S-shaped hysteresis, <I>i.e.</I> characteristics of strong ferromagnetism, with significant changes in the coercive field, remanent magnetization, and susceptibility. Induced magnetic dipoles formed by metal ions in DNA duplex in the presence of a magnetic field imparted ferromagnetic behaviour. By considering hysteresis and the magnitude of magnetization in a magnetization-magnetic field curve, Co<SUP>2+</SUP>-modified DNA DX lattices showed a relatively strong ferromagnetic nature with an increasing (decreasing) trend of coercive field and remanent magnetization when [Co<SUP>2+</SUP>]≤1mM ([Co<SUP>2+</SUP>]>1mM). In contrast, Ni<SUP>2+</SUP> and Zn<SUP>2+</SUP>-modified DNA DX lattices exhibited strong and weak ferromagnetic behaviours at lower (≤1mM for Ni<SUP>2+</SUP> and ≤0.5mM for Zn<SUP>2+</SUP>) and higher (>1mM for Ni<SUP>2+</SUP> and >0.5mM for Zn<SUP>2+</SUP>) concentrations of ions, respectively. About 1mM of [Co<SUP>2+</SUP>], [Ni<SUP>2+</SUP>] and [Zn<SUP>2+</SUP>] in DNA DX lattices was of special interest with regard to physical characteristics and was identified to be an optimum concentration of each ion. Finally, we measured the temperature-dependent magnetic characteristics of the metal-ion-modified DNA DX lattices. Nonzero magnetization and inverse susceptibility with almost constant values were observed between 25 and 300K, with no indication of a magnetic transition. This indicated that the magnetic Curie temperatures of Co<SUP>2+</SUP>, Ni<SUP>2+</SUP> and Zn<SUP>2+</SUP>-modified DNA DX lattices were above 300K.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Co<SUP>2+</SUP>, Ni<SUP>2+</SUP>, and Zn<SUP>2+</SUP>-modified DNA lattices are fabricated on a substrate. </LI> <LI> Magnetic characteristics of divalent-metal-ion-modified DNA lattices are studied. </LI> <LI> The magnetic measurement of the sample shows unique ferromagnetic characteristics. </LI> <LI> The magnetic hysteresis suggests potential feasibility of use in memory devices. </LI> </UL> </P>

A 2D DNA Lattice as an Ultrasensitive Detector for Beta Radiations

Dugasani, Sreekantha Reddy,Kim, Jang Ah,Kim, Byeonghoon,Joshirao, Pranav,Gnapareddy, Bramaramba,Vyas, Chirag,Kim, Taesung,Park, Sung Ha,Manchanda, Vijay American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.4

<P>There is growing demand for the development of efficient ultrasensitive radiation detectors to monitor the doses administered to individuals during therapeutic nuclear medicine which is often based on radiopharmaceuticals, especially those involving beta emitters. Recently biological materials are used in sensors in the nanobio disciplines due to their abilities to detect specific target materials or sites. Artificially designed two-dimensional (2D) DNA lattices grown on a substrate were analyzed after exposure to pure beta emitters, <SUP>90</SUP>Sr-<SUP>90</SUP>Y. We studied the Raman spectra and reflected intensities of DNA lattices at various distances from the source with different exposure times. Although beta particles have very low linear energy transfer values, the significant physical and chemical changes observed throughout the extremely thin, ∼0.6 nm, DNA lattices suggested the feasibility of using them to develop ultrasensitive detectors of beta radiations.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-4/am4055723/production/images/medium/am-2013-055723_0004.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am4055723'>ACS Electronic Supporting Info</A></P>

DNA and DNA–CTMA composite thin films embedded with carboxyl group-modified multi-walled carbon nanotubes

Dugasani, Sreekantha Reddy,Gnapareddy, Bramaramba,Kesama, Mallikarjuna Reddy,Ha, Tai Hwan,Park, Sung Ha Elsevier 2018 Journal of industrial and engineering chemistry Vol.68 No.-

<P><B>Abstract</B></P> <P>Although the intrinsic characteristics of DNA molecules and carbon nanotubes (CNT) are well known, fabrication methods and physical characteristics of CNT-embedded DNA thin films are rarely investigated. We report the construction and characterization of carboxyl (–COOH) group-modified multi-walled carbon nanotube (MWCNT–COOH)-embedded DNA and cetyltrimethyl-ammonium chloride-modified DNA (DNA–CTMA) composite thin films. Here, we examine the structural, compositional, chemical, spectroscopic, and electrical characteristics of DNA and DNA–CTMA thin films consisting of various concentrations of MWCNT–COOH. The MWCNT–COOH-embedded DNA and DNA–CTMA composite thin films may offer a platform for developing novel optoelectronics, energy harvesting, and sensing applications in physical, chemical, and biological sciences.</P> <P><B>Graphical abstract</B></P> <P>A facile methodology is developed to construct MWCNT–COOH-embedded DNA and DNA–CTMA composite thin films and distinct optoelectronic characteristics of the thin films are discussed.</P> <P>[DISPLAY OMISSION]</P>

Fabrication and optoelectronic characterisation of lanthanide- and metal-ion-doped DNA thin films

Dugasani, Sreekantha Reddy,Paulson, Bjorn,Ha, Taewoo,Jung, Tae Soo,Gnapareddy, Bramaramba,Kim, Jang Ah,Kim, Taesung,Kim, Hyun Jae,Kim, Jae Hoon,Oh, Kyunghwan,Park, Sung Ha IOP 2018 Journal of Physics. D, Applied Physics Vol.51 No.28

<P>DNA molecules doped with lanthanide and metal ions possess distinct functionalities, providing a feasibility to be utilised in various applications in nano- and biotechnologies. In the present work, we fabricate DNA thin films doped with seven different lanthanide ions (Ce<SUP>3+</SUP>, Dy<SUP>3+</SUP>, Eu<SUP>3+</SUP>, Gd<SUP>3+</SUP>, Tb<SUP>3+</SUP>, Tm<SUP>3+</SUP>, and Sm<SUP>3+</SUP>) and four different metal ions (Cu<SUP>2+</SUP>, Ni<SUP>2+</SUP>, Zn<SUP>2+</SUP>, and Co<SUP>2+</SUP>) by the drop-casting method. In addition, we conduct current, Hall transport, optical transmittance, and Raman spectroscopic measurements to investigate their electrical properties, carrier concentrations and Hall mobilities, optical band gaps, and vibrational and stretching modes, respectively. By analysing the current–voltage characteristics of the doped thin films with varying dopant concentrations, characteristic critical concentrations are observed, which are related to the significant enhancement of the thin film’s physical properties, compared with the pristine DNA. The extrema of the carrier concentrations and Hall mobilities of the doped thin films were observed approximately at the same critical concentrations. The optical band gaps gradually decreased with an increasing dopant concentration, caused by the intrinsic characteristics of both the dopants and DNA. Because of the preference of ions binding to DNA backbones through an electrostatic attraction and to bases via intercalation, the Raman band intensities gradually increase (or decrease) until reaching [Ln]<SUB>C</SUB> (or [M]<SUB>C</SUB>), where their trend is reversed. Ln-DNA and M-DNA thin films provide significant, specific, and novel physical characteristics which can be used in various applications.</P>