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Sustainable resource based carbon dot-silver nanohybrid: a strong tool against Culex quinquefasciatus, a common disease vector Shaswat Barua, Prasanta Kumar Raul, Reji Gopalakrishnan, Boddhaditya Das, Vanlal hmuaka, and Vijay Veer ACS Sustainable Chem. Eng., Just Accepted Manuscript • DOI: 10.1021/ acssuschemeng.6b00015 • Publication Date (Web): 14 Mar 2016 Downloaded from http://pubs.acs.org on March 17, 2016

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ACS Sustainable Chemistry & Engineering

Sustainable nanohybrid:

resource a

based

strong

carbon

tool

dot-silver

against

Culex

quinquefasciatus, a common disease vector Shaswat Barua, Prasanta K. Raul*, Reji Gopalakrishnan, Bodhadittya Das, Vanlalhmuaka, Vijay Veer Defence Research Laboratory, DRDO, Post bag no. 2, Tezpur-784001, Assam, India

*Corresponding Author E-mail: [email protected] ABSTRACT: With the evolution of material science, researchers are deeply concerned about the utility of sustainable resources for multifaceted advanced applications. Here, we project an abundant, non edible bio-resource based carbon dot silver nanohybrid as a highly competent larvicidal agent against Culex quinquefasciatus. Mosquitoes are the closest enemy of humankind since long time. Tropical areas around the globe suffer severe ailments due to the mosquitovector borne diseases. Japanese encephalitis, Lymphatic filariasis etc. are such fatal threats, spread by Culex species. With the emergence of nanotechnology, the perspectives of conventional anti-vector materials have changed dramatically. The C-dot precursor used here was the roots of Cyperus rotundus, a very abundant grass species found in the South Asian

1 ACS Paragon Plus Environment


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countries. The nanohybrid was synthesized by a simple thermal approach without the application of additional reducing agent. The nanohybrid was distributed within a narrow size window of 35% carbohydrate, where ipolamiide is predominant.21, 25 Formation of C-dots from carbohydrate sources has been depicted in the literature through hydrothermal methods.19It is proposed that during the first phase of the process, hydrolysis and subsequent decomposition of the carbohydrates takes place which yields different aldehydes, ketones and carboxylic acids. Aromatization and carbonization of such products followed by nuclear bursts result the C-dots.26 The C-dots generated thus contains a large number of surface hydroxyl groups. There is a high affinity of such structures for forming complexes with metal ions. This involves the release of a considerable number of protons and electrons as reported in literature.21, 27-28 The released electrons in turn help to reduce to Ag+ ions to Ag0. In this process, the simultaneous nucleation of silver and C-dots helps to generate the water soluble CDS. Figure 1 schematically shows the overall process. Characterization. Simultaneous generation of C-dot and silver nanoparticles was evident from the UV-visible spectrum shown in Figure 2 (a). UV absorption peak for C-dot was observed at 253 nm which is due to the n–π* transition of C=O band. Oxygeneous moieties present in the C-dot structure aided to the growth of the peak. The typical surface plasmon 6 ACS Paragon Plus Environment

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resonance peak for silver nanoparticles was visible at 418 nm, which is attributed to the electron gas on the nanoparticles, collectively oscillating at the surface.19 Surface functionalities of C-dots are primly responsible for their excellent water solubility. FTIR spectrum (Figure 2b) showed the presence of different functional groups on the CDS surface. The bands at 3416, 2929, 1680, 1632, 1400 and 1060 cm-1 clearly indicate the existence of –OH, C-H, C=O, C=C, C-O-C and C-O groups in the CDS structure.19, 25 TEM images (Figure 3 a-c) clearly show that the C-dots were formed with very small diameters along with the comparatively larger silver nanoparticles. The diameters of the silver nanoparticles centred between 5-18 nm, while that of the C-dots were within 2-6 nm. Both the particles were uniformly dispersed throughout without any sign of agglomeration. This implicates that the C-dots have imparted excellent stabilizing effect to the particles. Previously, also a few biocompatible, bio-derived materials like chitin, chitosan etc. were used to stabilize silver nanoparticles, which also enhanced their antimicrobial activity.29

However, due to the

low contrast on the substrate, C-dots are poorly visible in the images. HRTEM and IFFT images ascertained the layer spacing of a representative C-dot to be 0.32 nm, which resembles most of the literature reports (Figure 3 d).20 It was further noted that the diameter of the C-dots in the close proximity of silver nanoparticles were larger in comparison to the un-attached C-dots. This may be attributed to the high surface energy of the particles that induces agglomeration within them. In Figure 4, red and blue borders clearly differentiate the metallic silver nanoparticles and C-dots respectively. The overall TEM studies confirmed that both the particles were held together by strong interactive forces, which mutually stabilizes each other.16



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Larvicidal activity of the nanohybrid. Delving into the affect of CDS, bioassays were carried out against Culex quinquefasciatus mosquito larvae. Results indicated that LC50 and LC90 (95% fiducial limits) lies between 0.05 (0.045–0.055) and 0.211 (0.182–0.250) mg/L respectively (Table 1). Silver nanoparticles synthesized by using Tinospora cordifolia extract showed LC50 at 6.34 mg/L, while Nelumbo nucifera extract mediated ones showed LC50 at 0.69 against Anopheles subpictus and C. quinquefasciatus species respectively.30,31 However, these works used the crude plant extracts which were also having larvicidal activity. Despite the number of literature reports based on larvicidal silver nanoparticles, it is rare to find such commercial products. The vital reasons may be the toxicity of the nanoparticles and their poor stability with due course of time. Thus, the present nanohybrid can be used to overcome both of these demerits. Highly biocompatible C-dots also act as a stabilizing agent to the silver nanoparticles, by sterric hindrance. During the experiment it was noted that the dead larva turns faint black in color and settled at the bottom of the vessel (Figure 5 a). Optical microscopic images taken at 36X zoom showed that the nanohybrid was accumulated by the treated larva. The head, intestine and gut were visibly black (Figure 5b). Contrarily, the control larva retained the normal stature. This affirmation was further supported by the EDX studies which showed the presence of silver up to 2.86 atomic percentages (Figure 5 c-d) in the treated larva. Similar observation was witnessed in the SEM study. The SEM image of the control larva showed normal organization.8 While, the treated larva faced severe damage of the cuticular membrane (Figure 6 a-b). This allowed the intrusion of the nanohybrid within the larval body and subsequently ruptured the cellular organization of the gut and intestine.


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Anal segments also found to be denatured in the CDS treated ones. Deposition of the nanomaterials is clearly visible in the SEM image (Figure 6 d). Thus, it is quite obvious from the optical and scanning electron microscopic studies that treatment of CDS completely destroyed the normal metabolic system in the Culex larvae. Silver nanoparticles can bind to sulphur or phosphorus containing compounds like DNA which denatures the same or inhibits the enzyme activities, consequently diminishing the membrane permeability. Thus, alteration of proton motive force occurs and larval membrane gets damaged.32The most fascinating part of the study lies in the effective concentration of the nanohybrid applied for the larvicidal activity. Only 0.05 ppm of CDS showed LC50, which may be regarded as a remarkable achievement in controlling C. quinquefasciatus, the notorious vector of many life demanding diseases. Stability of the CDS: Environmental applications of nanomaterials demand the study of their stability accord. Accordingly, the stability of the present nanohybrid was monitored for 45 days under ambient conditions of temperature, pressure and light by UV-visible spectroscopy. The spectra showed that the material was quite stable in dispersed form for more than 30 days from preparation (Figure 7 a). It is clearly visible from the figure that on the 45th day of preparation, the characteristic UV absorption peak at around 418 nm broadens, implicating the agglomeration of the nanoparticles.7 Thus, CDS may be endorsed as an effective larvicidal material in drains and stagnant water bodies which would be stable against different environmental factors like temperature, photo-induced oxidation etc. Moreover, thermal stability of CDS is another interesting study, which revealed that the onset degradation temperature of the nanohybrid lies around 195 °C (Figure 7 b, TGA thermogarm was analyzed by a ShimadzuTG 50 analyzer, under constant nitrogen flow (30 mL min−1) and heating rate of 10 °C min−1). The same for silver nanoparticles and C-dots alone were reported to be 160 and 110 °C



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respectively.33,34 Thus, formation of nanohybrid synergistically increased the thermal stability of the individual nanomaterials.

CONCLUSION Utility of a sustainable resource based stable nanohybrid was projected in the present investigation for controlling C. quinquefasciatus larvae. The work demonstrated a facile method for the preparation of C-dot silver nanohybrid which may be adopted easily. The material was extremely effective at a concentration of only 0.05 ppm and stable against different environmental factors such as temperature, photo-induced oxidation etc.. Unison of larivicidal silver nanoparticles and bio-resource based C-dots may permit its sustained utility for actual field applications, after critically scrutinizing the toxicity accords. Author Contributions All the authors have significantly contributed to the reported work. The final version of the manuscript is approved by all the authors. ACKNOWLEDGMENT Authors

are

grateful

to

DBT,

India

for

financial

assistance

through

grant

no.

BT/518/NE/TBP/2013 dated December 12, 2014. SAIF, NEHU, Shillong is acknowledged for TEM imaging. REFERENCES (1) Mak, J.W. Epidemiology of Lymphatic Filariasis, Wiley Online Library, 2007, DOI: 10.1002/9780470513446.ch2.


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(2) Nitatpattana, N., Apiwathnasorn, C., Barbazan, P., Leemingsawat S., Yoksan, S. and Gonzalez, J. First isolation of Japanese encephalitis from Culex quinquefasciatus in Thailand, Southeast Asian J. Trop. Med. Public Health, 2005, 36, 875-878. (3) Okuno, T., Mitchell, J., Chen, P.S., Wang, J.S. and Lin, S.Y. Seasonal infection of Culex mosquitos and swine with Japanese encephalitis virus, Bull. Wld. Hlth. Org. 1973, 49, 347-352. (4) Al-Mehmadi, R.M. and Al-Khalaf, A.A. Larvicidal and histological effects of Melia azedarach extract on Culex quinquefasciatus Say larvae (Diptera: Culicidae), J. King Saud Univ. 2010, 22, 77–85. (5) Kamaraj, C., Abdul Rahman, A., Bagavan A., Abduz Zahir A., Elango, G., Kandan, P.,

Rajakumar, G., Marimuthu, S. and Santhoshkumar, T. Larvicidal efficacy of medicinal plant extracts against Anopheles stephensi and Culex quinquefasciatus (Diptera: Culicidae), Trop. Biomed. 2010, 27, 211-219. (6) Velayutham, K., Rahuman, A.A., Rajakumar, G., Roopan, S.M., Elango, G., Kamaraj, C., Marimuthu, S., Santhoshkumar, T., Iyappan, M. and Siva, C. Larvicidal activity of green synthesized silver nanoparticles using bark aqueous extract of Ficus racemosa against Culex quinquefasciatus and Culex gelidus, Asian Pac. J. Trop. Med. 2013, 6, 95-101 (7) Barua, S., Konwarh, R., Bhattacharya, S.S., Das, P., Devi, K.S. P., Maiti, T.K., Mandal, M. and Karak, N. Non-hazardous anticancerous and antibacterial colloidal ‘green’silver nanoparticles, Colloids Surf., B 2013, 105, 37-42. (8) Barua, S., Konwarh, R., Mandal, M., Gopalakrishnan, R., Kumar, D. and Karak, N. Biomimetically prepared antibacterial, free radical scavenging poly (ethylene glycol) supported silver nanoparticles as Aedes albopictus larvicide, Adv. Sci. Eng. Med. 2013, 5, 291-298. 11 ACS Paragon Plus Environment


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(9) Barua, S., Das, G., Aidew, L., Buragohain, A.K. and Karak, N. Copper–copper oxide coated nanofibrillar cellulose: a promising biomaterial, RSC Adv. 2013, 3, 14997-15004. (10) Muthukumaran, U., Govindarajan, M. and Rajeswary, M. Mosquito larvicidal potential of silver nanoparticles synthesized using Chomelia asiatica (Rubiaceae) against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae), Parasitol Res. 2015, 114, 989–999. (11) Sohn, E.K., Johari, S.A., Kim, T.G., Kim, J.K., Kim, E., Lee, G.H., Chung, Y.S. and Yu, J. Aquatic toxicity comparison of silver nanoparticles and silver nanowires, BioMed. Res. Int. 2015, 1-12. (12) Xu, X., Ray, R., Gu, Y., Ploehn, H.J., Gearheart, L., Raker, K. and Scrivens, W.A. Electrophoretic Analysis and Purification of Fluorescent Single-Walled Carbon Nanotube Fragments, J. Am. Chem. Soc. 2004, 126, 12736-12737. (13) Baker, S.N. and Baker, G.A. Luminescent carbon nanodots: emergent nanolights, Angew. Chem. Int. Ed. 2010, 49, 6726-6744. (14) Lim, S.Y., Shen, W. and Gao, Z. Carbon quantum dots and their applications, Chem. Soc. Rev., 2015, 44, 362-381. (15) Shen, L., Chen, M., Hu, L., Chen, X. and Wang, J. Growth and stabilization of silver nanoparticles on carbon dots and sensing application, Langmuir 2013, 29, 16135-16140. (16) Choi, Y., Ryu, G.H., Min, S.H., Lee, B.R., Song, M.H., Lee, Z. and Kim, B. Interfacecontrolled synthesis of heterodimeric silvercarbon nanoparticles derived from polysaccharides, ACS Nano, 2014, 8, 11377-11385.


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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(17) Yang, J., Han, S., Zheng, H., Dong, H. and Liu, H. Preparation and application of micro/nanoparticles based on natural polysaccharides, Carbohydr. Polym. 2015, 123, 53–66.

(18) Mehta, V.N., Jha, S., Singhalc, R.K. and Kailasa, S.K. Preparation of multicolor emitting carbon dots for HeLa cell imaging, New J. Chem. 2014, 38, 6152-6160. (19) De, B. and Karak, N. A green and facile approach for the synthesis of water soluble fluorescent carbon dots from banana juice, RSC Adv. 2013, 3, 8286-8290. (20) Gogoi, S., Kumar, M., Mandal, B.B. and Karak, N. High performance luminescent thermosetting

waterborne

hyperbranched

polyurethane/carbon

quantum

dot

nanocomposite with in vitro cytocompatibility, Compos. Sci. Tech. 2015, 118, 39-46. (21) Kumar, N., Singh, J.P., Ranjan, R., Devi, S. and Srinivasan V, M. Bioethanol production from weed plant (Cyperus rotundus) by enzymatic hydrolysis, Adv. Appl. Sci. Res. 2013, 4, 299-302. (22) WHO, Report of the WHO Informal Consultation on the evaluation and testing of insecticides, CTD/WHO PES/IC/96.1, WHO, Geneva, 2011 p. 69. (23) Abbott, W.S. A method of computing the effectiveness of an insecticide, J. Econ. Entomol. 1925, 18, 265-267. (24) Liu, J., Willfor, S. and Xu, C. A review of bioactive plant polysaccharides: Biological activities, functionalization, and biomedical applications, Bioact. Carbohydr. Diet. Fib. 2015, 5, 31-61. (25) Mohamed, G.A. Iridoids and other constituents from Cyperus rotundus L. rhizomes, Bull. Fac. Pharm. Cairo Univ. 2015, 53, 5–9.



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(26) Falco, C., Baccile, N. and Titirici, M.M. Morphological and structural differences between glucose, cellulose and lignocellulosic biomass derived hydrothermal carbons, Green Chem. 2011, 13, 3273-3281. (27) Ryu, J., Suh, Y.W., Suh, D.J. and Ahn, D.J. Hydrothermal preparation of carbon microspheres from mono-saccharides and phenolic compounds, Carbon, 2010, 48, 1990-1998. (28) Ishihara, M., Nguyen, V.Q.,Mori, Y., Nakamura, S. and Hattori, H. Adsorption of Silver Nanoparticles onto Different Surface Structures of Chitin/Chitosan and Correlations with Antimicrobial Activities, Int. J. Mol. Sci. 2015, 16, 13973-13988. (29) Jayaseelan, C., Rahuman, A.A., Rajkumar, G., Kirthi, A.V., Santhoshkumar, T., Marimuthu, S., Bagavan, A., Kamaraj, C., Jahir, A.A. and Elango, G. Synthesis of pediculocidal and larvicidal silver nanoparticles by leaf extract from heartleaf moonseed plant, Tinospora cordifolia Miers, Parasitol. Res. 2011, 109, 185-194. (30) Santhoshkumar, T., Rahuman, A.A., Rajkumar, G., Marimuthu, Bagavan, A., Jayaseelan, C., Jahir, A.A., Elango, G. and Kamaraj, C. Synthesis of silver nanoparticles using Nelumbo nucifera leaf extract and its larvicidal activity against malaria and filariasis vectors, Parasitol. Res. 2011, 108, 693. (31) Mitra, S., Chandra, S., Patra, P., Pramanik, P. and Goswami, A. Novel fluorescent matrix embedded carbon quantum dots for the production of stable gold and silver hydrosols, J. Mater. Chem. 2011, 21, 17638-17641. (32) Sareen Sarah, J., Pillai Raji, K., Chandramohanakumar N. and Balagopalan, M. Larvicidal Potential of Biologically Synthesised Silver Nanoparticles against Aedes Albopictus, Res. J. Rec. Sci. 2012, 1, 52-56.


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(33) Khalil, M.M.H., Ismail, E.H., El-Baghdady, K.Z. and Mohamed, D. Green synthesis of silver nanoparticles using olive leaf extract and its antibacterial activity, Arabian J. Chem. 2014, 7, 1131–1139. (34) Mewada, A., Pandey, S., Shinde, S., Mishra, N., Oza, G., Thakur, M., Sharon, M. and Sharon, M. Green synthesis of biocompatible carbon dots using aqueous extract of Trapa bispinosa peel, Mater. Sci. Eng. C 2013, 33, 2914-2917.



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Figure 1. Probable mechanism of formation of CDS


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Figure2. (a) UV-visible spectra of CDS after 2 h of reaction and (b) FTIR spectrum of CDS



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Figure 3. TEM images of (a-c) CDS and (d) HRTEM images of a C-dot (on-set IFFT of the Cdot, showing the layer spacing)


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Figure 4. Representative HRTEM images of C-dots (blue lines) and silver nanoparticles (red lines) held together by strong interactive forces



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Figure 5. (a) Representative image of the experiment, where death of larvae were settled down (on-set: a few dead larvae), (b) optical microscopic image of a control larva and a CDS-treated larva, showing the accumulation of CDS within the larval body and EDX spectra of representative (c) control and (d) CDS treated larva


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Figure 6. (a) SEM images of (a) a representative control larva, (b) CDS treated larva showing the disruption of the cuticular layer and intestine, (c) normal anal segments of a representative control larva and (d) deposition of CDS onto the anal segments of a treated larva



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Figure 7. (a) UV-visible spectra showing the stability of CDS on 1st, 15th, 30th and 45th days from preparation and (b) TGA thermogram of CDS


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Table 1. Dose dependent larvicidal activity of CDS, showing the LC50 and LC90 against the mosquito larva of Culex quinquefasciatus

Dose

Mortality

LC50 (mg/L)

LC90 (mg/L)

(mg/L)

(%±SEmean)

(95% fiducial limits)

(95% fiducial limits)

0.4

100

0.3

92.95±4.90

0.2

83.08±2.18

0.05

0.211

0.1

69.92±5.42

(0.045-0.055)

(0.182-0.250)

0.05

56.28±4.10

0.04

42.19±3.44

0.03

32.38±4.48

0.02

21.49±3.29

0.01

7.80±3.73



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TOC graphic (For Table of Contents Use Only)

Sustainable nanohybrid:

resource a

based

strong

carbon

tool

dot-silver

against

Culex

quinquefasciatus, a common disease vector Shaswat Barua, Prasanta K. Raul*, Reji Gopalakrishnan, Bodhadittya Das, Vanlalhmuaka, Vijay Veer

SYNOPSIS Sustainable resource based C-dot silver nanohybrid was used as a strong larvicidal agent against Culex quinquefasciatus, the vector of Japanese encephalitis, lymphatic filariasis etc.


Sustainable-Resource-Based Carbon DotâSilver ... - ACS Publications

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