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

Sreekantha Reddy Dugasani,GNAPAREDDYBRAMARAMBA,Mallikarjuna Reddy Kesama,하태환,박성하 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.68 No.-

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.

Electrical and mechanical properties of diluted magnetic semiconductor Zn_1-xMn_xS nanocrystalline films

Sreekantha Reddy, D.,Kang, B.,Yu, S.C.,Dwarakanadha Reddy, Y.,Sharma, S.K.,Gunasekhar, K.R.,Rao, K.N.,Sreedhara Reddy, P. Elsevier 2009 Current Applied Physics Vol.9 No.2

Nanostructured Zn<SUB>1-x</SUB>Mn<SUB>x</SUB>S films (0=<x=<0.25) were deposited on glass substrates by simple resistive thermal evaporation technique. All the films were deposited at 300K in a vacuum of 2x10<SUP>-6</SUP>m bar. All the films temperature dependence of resistivity revealed semiconducting behaviour of the samples. Hot probe test revealed that all the samples exhibited n-type conductivity. The nanohardness of the films ranges from 4.7 to 9.9GPa, Young's modulus value ranging 69.7-94.2GPa.

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

Sreekantha Reddy Dugasani,Bramaramba Gnapareddy,Sekhar Babu Mitta,박성하 한국물리학회 2019 Current Applied Physics Vol.19 No.3

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.

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>

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>

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>

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>

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>

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>