Fluorescence resonance energy transfer‑based sensor with silver‑conjugated orange peel waste‑derived carbon dots for melamine detection

Pramila Murugesan,N. Libiya,J. A. Moses,C. Anandharamakrishnan 한국탄소학회 2023 Carbon Letters Vol.33 No.7

This work involves the development of a novel waste-derived carbon dots (CDs) conjugated with silver (Ag) nanohybrid system-based Fluorescence Resonance Energy Transfer (FRET) sensor for the detection of melamine. CDs and Ag nanoparticles served as energy donors and energy acceptors, respectively. CDs were synthesized from orange peel waste through a combined hydrothermal and ultra-sonication route. The synthesized CDs had hydroxyl, amino, and carboxyl groups on their surface, explaining that waste-derived CDs can act as reducing and stabilizing agents and showed strong absorption and fluorescence emission at 305 and 460 nm, respectively. The bandgap, linear refractive index, conduction band, and valance band potential of CDs were observed to be 2.86, 1.849, 1.14, and 4.002 eV, respectively. No significant difference was observed in the fluorescence properties at different pH (acid and alkaline) and ionic concentrations. Given their fluorescent nature, the synthesized CDs were used for the detection of melamine. The fluorescence of CDs was found to be quenched by Ag+ due to the FRET energy transfer between CDs to Ag. Notably, the zeta potential of Ag@CDs was changed from ? 28.7 mV to ? 30.6 mV after the incorporation of Ag+. Ag@CDs showed excellent selectivity and sensitivity toward the sensing of melamine in the aqueous solutions with the limit of detection ~ 0.85 μM. Increasing the melamine level also raises the FL intensity of Ag@CDs. The substrate was effectively used in the detection of melamine in milk as a real application and the recovery percentage was found to be 98.03%. Moreover, other adulterants such as urea and formaldehyde can be detected selectively by Ag@CDs. Overall, the synthesized Ag@CDs can be used as an efficient material for sensing applications involving such food adulterants.

THE POVERTY PARADIGM AND DISABILTY

( Pramila Balasundaram ) 대구대학교 한국특수교육문제연구소 2015 Asia-Pacific Journal of Intellectual Disabilities Vol.2 No.2

페로브스카이트 태양 전지의 스크린 인쇄 및 스핀 코팅 정공 수송층 비교

Pramila Patil,임수만,나석인 한국화상학회 2020 한국화상학회지 Vol.26 No.1

정공 및 전자 수송층은 페로브스카이트 소자에서 효율 및 안정성을 증가시키는 중요한 역할을 하고 있다. 특히, NiO가 정공수송층 으로서 태양 전지 장치의 효율을 향상시키는 데 중요한 역할을 하는 것으로 알려져 있기 때문에 대부분의 연구자들이 태양 전지의 HTL(hole transport layer) 물질로서 NiO를 연구하고 있다. 본 연구는 NiO를 스크린 인쇄 및 스핀 코팅 방법으로 각각 제조 및 비교실험 하였으며, 서로의 특이점을 확인하고자 하였다. 실험결과 스크린 인쇄 기술로 10.65 %의 태양 전지 효율을 달성 한 반면 스핀 코팅 된 HTL로 18.61 % 효율을 달성했으며 또한 AFM 분석을 사용하여 HTL 층의 거칠기를 연 구하였다. 스크린 프린팅으로 형성된 필름의 불균일성으로 인해 HTL 필름에서 효율이 감소하는 것으로 밝혀졌다. Hole and electron transport layers play significant role in the perovskite devices to increase the efficiency and stability of the device. Here, we have used NiO as hole transport layer (HTL) fabricated by screen printing and spin coating methods. Most of researchers are working on the NiO as the HTL material in solar cell. NiO is important for enhancing the efficiency of solar cell devices. We achieved solar cell efficiency of 10.65% with screen printing technique whereas 18.61% efficiency was obtained with spin coated HTL. We also studied the roughness of the HTL layer by using AFM analysis. The efficiency was found to decrease with screen-printed HTL, as the film formed with screen-printing is not uniform.

Design and Synthesis of Fluorinated and/or Hydroxylated 2-Arylidene-1-indanone Derivatives as an Inhibitor of LPS-stimulated ROS Production in RAW 264.7 Macrophages with Structure–Activity Relationship Study

Pramila Katila,Aastha Shrestha,아라자나쉬레스타,Ritina Shrestha,박필훈,이응석 대한화학회 2018 Bulletin of the Korean Chemical Society Vol.39 No.12

A new series of thirty-two fluorinated and/or hydroxylated 2-arylidene-1-indanone derivatives were systematically designed, synthesized, and evaluated for their inhibitory activity against LPS-stimulated ROS production in RAW 264.7 macrophages. 5/6-Fluoro-1-indanone or 4-, 5-, 6-, or 7-hydroxyindanone moiety along with ortho-, meta-, or para-hydroxyphenyl, furanyl or thiophenyl moiety was prepared and evaluated. Among the synthesized compounds, compound 11 possessing 6-hydroxy-1-indanone moiety along with 5-chlorothiophenyl moiety was found to have the most potent inhibitory effect on the production of ROS in LPS-stimulated RAW 264.7 macrophages with an IC50 value of 3.29??M.

Schottky junction interfacial properties at high temperature: A case of AgNWs embedded metal oxide/p-Si

Mahala, Pramila,Patel, Malkeshkumar,Gupta, Navneet,Kim, Joondong,Lee, Byung Ha North-Holland 2018 Physica. B, Condensed matter Vol.537 No.-

<P><B>Abstract</B></P> <P>Studying the performance limiting parameters of the Schottky device is an urgent issue, which are addressed herein by thermally stable silver nanowire (AgNW) embedded metal oxide/p-Si Schottky device. Temperature and bias dependent junction interfacial properties of AgNW-ITO/Si Schottky photoelectric device are reported. The current−voltage−temperature (<I>I</I>−<I>V</I>−<I>T</I>), capacitance-voltage-temperature (<I>C</I>−<I>V</I>−<I>T</I>) and impedance analysis have been carried out in the high-temperature region. The ideality factor and barrier height of Schottky junction are assessed using <I>I</I>−<I>V</I>−<I>T</I> characteristics and thermionic emission, to reveal the decrease of ideality factor and increase of barrier height by the increasing of temperature. The extracted values of laterally homogeneous Schottky <I>(ϕ</I> <SUB> <I>b</I> </SUB>) and ideality factor (<I>n)</I> are approximately 0.73 eV and 1.58, respectively. Series resistance (R<SUB>s</SUB>) assessed using Cheung's method and found that it decreases with the increase of temperature. A linear response of R<SUB>s</SUB> of AgNW-ITO/Si Schottky junction is observed with respect to change in forward bias, i.e. dR<SUB>S</SUB>/dV from 0 to 0.7 V is in the range of 36.12–36.43 Ω with a rate of 1.44 Ω/V. Impedance spectroscopy is used to study the effect of bias voltage and temperature on intrinsic Schottky properties which are responsible for photoconversion efficiency. These systematic analyses are useful for the AgNWs-embedding Si solar cells or photoelectrochemical cells.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Interfacial properties of AgNWs embedded ITO-p-Si Schottky junction. </LI> <LI> Surface interface of AgNW is demonstrated. </LI> <LI> High temperature characteristics were investigated. </LI> <LI> Impedance analyses were presented for photo-conversion mechanism. </LI> </UL> </P>

Convolution Properties of Certain Class of Multivalent Meromorphic Functions

Vijaywargiya, Pramila Department of Mathematics 2009 Kyungpook mathematical journal Vol.49 No.4

The purpose of the present paper is to introduce a new subclass of meromorphic multivalent functions defined by using a linear operator associated with the generalized hypergeometric function. Some properties of this class are established here by using the principle of differential subordination and convolution in geometric function theory.

CMOS image sensor based HIV diagnosis: a smart system for point-of-care approach

Jasmine Pramila Devadhasan1,김상효 한국바이오칩학회 2013 BioChip Journal Vol.7 No.3

We report on the use of a complementary metal oxide semiconductor (CMOS) image sensor in an immunodiagnostic system for detecting the human immunodeficiency virus (HIV). It is based on photon counting and the interaction of the HIV antigen (Ag)with respective antibodies, which are deposited in various thicknesses on indium nanoparticles (InNPs) substrate. The sensor measures the number of photons that depends on the concentration of HIV Ag and converts them into digital numbers. Photons are refracted on the protein adsorbed InNP substrate and hit the CMOS image sensor surface based on the Ag concentration. Topographical studies such as field emission scanning electron microscopy (FE-SEM) and fluorescence microscopy images are demonstrated the reliability of this scheme. Also, the UV-spectral studies proved the efficiency of the analysis with InNP substrate. The sensor is simple, compact, highly specific and accurate. Also, it can detect HIV at levels as low as 10 fg mL-1. Therefore, the sophisticated system of the CMOS image sensor based immunodetection now requires point-of-care (POC) diagnosis.

Alpinia calcarata: potential source for the fabrication of bioactive silver nanoparticles

Khandel Pramila,Shahi Sushil Kumar,Soni Deepak Kumar,Yadaw Ravi Kumar,Kanwar Leeladhar 나노기술연구협의회 2018 Nano Convergence Vol.5 No.37

In the present study silver nanoparticles fabricated by using leaf extract of Alpinia calcarata. We have also studied the effect of various experimental parameters viz., metal ion concentration, pH and incubation period on nanoparticle biosynthesis. Results of optimization showed that metal ion concentration of 1.5 mM, alkaline pH and incubation period of 12 h were the optimum conditions for metal nanoparticle biosynthesis. Synthesized silver nanoparticles were characterized by UV–Visible spectroscopy, Dynamic light scattering (DLS), Zeta potential analysis, Fourier transform infrared spectroscopy (FTIR), Inductively coupled plasma-optical emission spectrometry (ICP-OES), Transmission electron microscopy (TEM) and X-ray diffraction analysis (XRD). The UV–visible spectrum shows a sharp peak at 420 nm which was due to the surface plasmon resonance of the silver nanoparticles. Effect of several phytochemicals present in A. calcarata, on synthesis of silver nanoparticles was studied by Fourier transform infrared spectroscopy. The results indicate that the flavonoids, phytosterol, quinones and phenolic compounds present in the plant extract plays a major role in formation of silver nanoparticles in their respective ions in solution. Results of TEM and XRD analysis showed that synthesized silver nanoparticles were mostly spherical in shape with an average diameter of 27.2 ± 0.2.5 nm and highly crystalline in nature. Moreover the synthesized silver nanoparticles were also evaluated for their potential antibacterial and antioxidant activities. It showed good antibacterial activity as well as antioxidant activity. Thus the obtained result provides a scientific support that leaf extract of A. calcarata can be used efficiently in the production of potential bioactive silver nanoparticles with several pharmaceutical applications.

Introduction of amino moiety enhances the inhibitory potency of 1-tetralone chalcone derivatives against LPS-stimulated reactive oxygen species production in RAW 264.7 macrophages

Katila, Pramila,Shrestha, Aastha,Shrestha, Aarajana,Shrestha, Ritina,Park, Pil-Hoon,Lee, Eung-Seok Elsevier 2019 Bioorganic chemistry Vol.87 No.-

<P><B>Abstract</B></P> <P>The design and synthesis of a series of thirty-two halogenated 1-tetralone or 6-amino-1-tetralone chalcone derivatives was achieved by the Claisen-Schmidt condensation reaction and were evaluated for their inhibitory effects against ROS production in LPS-stimulated RAW 264.7 macrophages. It was observed that the introduction of amino moiety into 1-tetralone skeleton greatly increased the inhibitory potency compared to corresponding 1-tetralone chalcones. Among the synthesized compounds, compound <B>18</B> which consists of 6-amino-1-tetralone skeleton together with <I>o</I>-fluorobenzylidene showed the most potent ROS inhibitory effect with IC<SUB>50</SUB> value of 0.25 ± 0.13 µM. SAR analysis revealed that amino moiety at the 6th position of 1-tetralone chalcones have an important role for exerting the greater ROS inhibitory potency in LPS-stimulated RAW 264.7 macrophages than those exhibited by 1-tetralone chalcones alone.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Halogenated 1-tetralone/6-amino-1-tetralone chalcone derivatives were synthesized. </LI> <LI> ROS Inhibitory effect in LPS-stimulated RAW 264.7 macrophages was examined. </LI> <LI> Compounds <B>18</B> showed the most potent ROS inhibition potency. </LI> <LI> Intro duction of amino group at the 6th position was enhanced the ROS inhibition. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Overview of CMOS image sensor use in molecular diagnostics

Jasmine Pramila Devadhasan,유인상,김상효 한국물리학회 2015 Current Applied Physics Vol.15 No.3

CMOS sensors comprise an important tool in bioscientific applications. This review focuses on CMOS sensor-based molecular diagnostics of DNA, protein, and metabolic molecules. Herein, gene sequencing, DNAeDNA hybridization, single nucleotide polymorphisms (SNP), protein interactions, peptide interactions, antigeneantibody (AgeAb) interactions, as well as glucose and cholesterol monitoring using CMOS sensors are discussed along with existing experimental outcomes. CMOS sensor based electrochemical, optical, impedance, dual, continuous, and label-free analysis and their related integration techniques are explained. Moreover, we describe the utilization of a CMOS chip in microarray fabrication, assay platform development, and transducer incorporation for molecular diagnostics. Furthermore, CMOS sensor-based point-of-care (POC) applications, other biological analyses, and the role of nanoparticles in biomolecular sensing are discussed. Future directions include information about the novel integration of CMOS sensor-based molecular diagnostic devices with a central focus towards enhancement of POC approaches. This review is helpful in creating highly sensitive, cheaper, and user-friendly biomedical devices with modern dimensions.