Synthesis of ZnS:Mn- Fe3O4 bifunctional nanoparticles by inverse microemulsion method

The designed bifunctional nanoparticles can act similar functions like core-shell structure nanoparticles, providing simultanously photoluminescence as labeling agent in biomedical appli[r]

(1)

Original article

Synthesis of ZnS:MneFe3O4 bifunctional nanoparticles by inverse

microemulsion method

Chu Tien Dunga,b, Luu Manh Quynha, Nguyen Phuong Linha, Nguyen Hoang Nama,c,*,

Nguyen Hoang Luongc

aFaculty of Physics, Hanoi University of Science, Vietnam National University, Hanoi, 334 Nguyen Trai, Hanoi, Viet Nam bUniversity of Transport and Communications, Cau Giay, Hanoi, Viet Nam

cNano and Energy Center, Hanoi University of Science, Vietnam National University, Hanoi, 334 Nguyen Trai, Hanoi, Viet Nam

a r t i c l e i n f o

Article history: Received 31 May 2016 Accepted 10 June 2016 Available online 17 June 2016 Keywords:

ZnS:Mn Fe3O4

Bifunctional nanoparticles Magnetic materials Inverse microemulsion

a b s t r a c t

ZnS:MneFe3O4 bifunctional nanoparticles were synthesized by inverse microemulsion method for biomedicine applications The bifunctional nanoparticles were combined from prepared ZnS:Mn and Fe3O4nanoparticles in a SiO2cover matrix Results show that bifunctional nanoparticles, apart from exhibiting magnetism, have photoluminescence properties, which support the applications targeting biomedicineﬂuorescent diagnostics as well as magnetic cell sorting or drug delivery

© 2016 The Authors Publishing services by Elsevier B.V on behalf of Vietnam National University, Hanoi This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

1 Introduction

Multifunctional nanoparticles are of a great interest in recent development due to the growing needs in biomedical applications They have potential to integrate various functionalities such as providing contrast for labeling agent, image-guided therapies, targeted drug delivery, thermal therapies or simultaneously serve as magnetic separator[1e4] At the beginning, core-shell struc-tures were considered to improve appropriate physical as well as chemical properties and combine them in one nanoparticle Advanced polymer coating such as polyethylene glycol was usually used as functionalizing agent to make the nanoparticles have good bio-compatibility[5e9] Some semiconductor coatings have been developed as photoluminescent shell to increase the luminescence

[10e12]as well as making a cover against the toxic element release from core material, such as Se, Cd[11] In some other applications, metal and silica shells were coated for protecting the core mate-rials[13,14] However, the synthesis method of core-shell structure referred tight conditions and expertise laboratory craftsmanship In this paper, a simple method of inversed microemulsion was

used to prepare new bifunctional nanoparticles ZnS:MneFe3O4

from individual Mn-doped ZnS (ZnS:Mn) semiconductor nano-particles and Fe3O4magnetic nanoparticles in SiO2coating matrix

ZnS:Mn semiconductor nanoparticles can be employed for label-ing of clinical tumor tissues[15] The magnetic nanoparticles with superparamagnetic properties can be used as targeted delivery of drug and/or gene, magnetic separation as well as magnetic ther-apies [16e19] The designed bifunctional nanoparticles can act similar functions like core-shell structure nanoparticles, providing simultanously photoluminescence as labeling agent in biomedical application, biocompatible and can be also puriﬁed by magnetic separator or can be used for drug delivery due to their magnetism, event under the coating of SiO2matrix

2 Experimental

2.1 Synthesis of ZnS:Mn nanoparticles

ZnS:Mn nanoparticles were synthesized by ultrasound-assisted co-precipitation method using sodium sulphide (Na2S) as S2ion

source ZnCl20.5 M were mixed with surfactance sodium dodecyl

sulfate (SDS), CH3(CH2)11SO4Na) 0.25 M and Mn(CH3COO)20.5 M

to get precursor solution The molar ratio of Mn/Zn was 1/10 This solution was ultrasonicated with the pulse mode on:off being 2s:2s The ultrasonic power and the frequency was 225 W and

* Corresponding author Faculty of Physics, Hanoi University of Science, Vietnam National University, Hanoi, 334 Nguyen Trai, Hanoi, Viet Nam

E-mail address:namnh@hus.edu.vn(N.H Nam)

Peer review under responsibility of Vietnam National University, Hanoi

Contents lists available atScienceDirect

Journal of Science: Advanced Materials and Devices

j o u r n a l h o m e p a g e : w w w e l s e v i e r c o m / l o c a t e / j s a m d

http://dx.doi.org/10.1016/j.jsamd.2016.06.006

2468-2179/© 2016 The Authors Publishing services by Elsevier B.V on behalf of Vietnam National University, Hanoi This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

(2)

20 kHz, respectively During the ultrasonicating, Na2S solution was

slowly added into the precursor solution After h, the ZnS:Mn nanoparticles were collected by washing times with distilled water before being dispersed in isopropanol

2.2 Synthesis of Fe3O4nanoparticles

Fe3O4 nanoparticles were synthesized by co-precipitation

method[20,21]using Fe2ỵ/Fe3ỵwith 1:2 M ratios from the two chloride salts of FeCl2and FeCl3, which were diluted to 0.01 M/

0.02 M concentration The mixed solution was vigorously stirred and kept at 60C before NH4OH 30% was being added to have the

black color precipitation Theﬁnal solution was puriﬁed by mag-netic separation with ethanol and distilled water several times to decontaminate the auxiliary chemicals Fe3O4nanoparticles, then,

were dispersed in isopropanol

2.3 Synthesis of ZnS:MneFe3O4bifunctional nanoparticles

The bifunctional nanoparticles were combined from above two kinds of nanoparticles by inverse microemulsion method The in-verse microemulsion was created by mixing hydrophobic phase of toluene and hydrophilic phase that was made from the mixture of ZnS:Mn solution and Fe3O4 solution in isopropanol right after

synthesis and the solution of NH4OH with distilled water Under

sonic bath, tethraethylorthosilicate (TEOS) was added to react with

water in solution to form amorphous SiO2 matrix that covered

both types of particles

The morphology of the ZnS:Mn, Fe3O4and the ZnS:MneFe3O4

nanoparticles was investigated by transmission electron micro-scope (TEM, JEOL- JEM1010) The structure of nanoparticles was studied using X-ray diffractormeter (XRD, Bruker D5005) The average crystallite size, d, is calculated from the line broadening using Scherrer's formula: d¼ 0.9l/(Bcosq), where B is the half

maximum line width and l is the wavelength of X-rays The

chemical composition of the nanoparticles was studied by using an energy dispersion spectroscopy (EDS) included in JEOL 5410LV scanning electron microscope and the chemical bonding was investigated by using Fourier Transformation Infra-Red (FTIR 6300, Shimadzu) absorption Magnetic properties of samples were studied by using DMS 880 Vibrating Sample Magnetometer (VSM)

with a maximum magneticﬁeld of 13.5 kOe at room temperature

Optical properties of sample were investigated by using the Flourolog FL 3-22 photoluminescence (PL) spectroscopy (Jobine Yvone Spex, USA)

3 Results and discussion

Fig 1shows the TEM images of the ZnS:Mn, Fe3O4, and the

ZnS:MneFe3O4nanoparticles The TEM image of ZnS:Mn does not

show very clear shape of nanoparticles, that may be due to the amorphous cover of synthesized nanoparticles The TEM image of the Fe3O4nanoparticles shows well-dispersed nanoparticles with

size of about 15 nm The TEM image of the ZnS:MneFe3O4

nano-particles shows the colloids with the mean size of around 45 nm and does not show small colloids of around 15 nm and nm, which are typical sizes of Fe3O4and ZnS:Mn nanoparticles, respectively

The ZnS:MneFe3O4 nanoparticles contain ZnS:Mn and Fe3O4

nanoparticles inside This microstructure of the ZnS:MneFe3O4

nanoparticles is supported by the results of measurements dis-cussed below

The XRD patterns of the Fe3O4, ZnS:Mn and ZnS:MneFe3O4

nanoparticles are shown in Fig The pattern of the

co-precipitation synthesized Fe3O4nanoparticles is characteristic of

the Fe3O4structure with diffraction peaks at 30.1, 36.0, 43.9,

53.6, 57.5va 63.1which can be assigned with (200), (311), (400), (422), (511) va (440) reﬂections, respectively Fe3O4nanoparticles

have an inverse spinel structure with oxygen forming face-centered cubic (fcc) structure with F3dm space group From

diffraction peaks we obtained the lattice parameter of

8.36 ± 0.04 Å Using Scherrer's formula, the particle size was estimated to be around 10 nm The pattern of the synthesized ZnS:Mn nanoparticles shows diffraction peaks at 29.1, 48.1, 57.5

Fig TEM images of (a) ZnS:Mn, (b) Fe3O4and (c) ZnS:MneFe3O4nanoparticles

(3)

They can be ascribed as (111), (200), (220) reﬂections, respectively The obtained lattice parameter of 5.32± 0.02 Å for fcc structure and the particle size was estimated to be around 4.7 nm, in agreement with particles size observed by TEM image The XRD

pattern of the combined ZnS:MneFe3O4 nanoparticles shows

typical amorphous structure of SiO2coated matrix with the sign of

the (311), (400), (422), (511) reﬂections of Fe3O4structure and the

weaker (200), (220) reﬂections of ZnS:Mn structure The SiO2

cover could absorb X-ray, leading to the disappearance of some XRD peaks of ZnS:Mn and Fe3O4nanoparticles

The FTIR absorption spectra of the Fe3O4, ZnS:Mn and the

ZnS:MneFe3O4nanoparticles are shown inFig All the spectra

show the broad peaks at 3400 cm1of OeH stretching vibration

[22] and the peaks at 1628, 2340, 2361 cm1 which can be

assigned to CeO vibration of CO2[22,23]related to the air

back-ground of the measurement These peaks are due to the presence of CO2and H2O in all the samples The spectrum of ZnS:MneFe3O4

shows typical absorption peaks of ZnS:Mn such as peaks at 1106, 617 and 465 cm1of ZneS bonding or peak at 1174 cm1 which

appears when Mn2ỵis doped into ZnS crystal[24] The two peaks

at 2851 and 2924 cm1, which appear both in ZnS:Mn and

ZnS:MneFe3O4samples, are due to the microstructure formation

of ZnS:Mn nanoparticles[24] The spectrum of ZnS:MneFe3O4also

shows typical absorption peaks of Fe3O4 nanoparticles such as

peak at 560 cm1of FeeO vibration[25] Furthermore, this spec-trum has peaks of SiO2such as peaks at 797 cm1and 960 cm1 [26,27] These results and the XRD results support that the ZnS:MneFe3O4 nanoparticles were successfully combined from

ZnS:Mn and Fe3O4nanoparticles in SiO2matrix

Fig shows the PL spectrum of ZnS:Mn and that of ZnS:MneFe3O4nanoparticles excited at 335 nm The spectrum of

ZnS:Mn nanoparticles have the peak at 438 nm which is originated from defects caused by missing of some Zn ion in ZnS crystal structure, and the peak at 595 nm which is originated from the

4T

1/6A1 transition in 3d5electronic layer of Mn2ỵion[28e30]

The spectrum of ZnS:MneFe3O4nanoparticles also has two

pho-toluminescence peaks, one at 595 nm and the other at 425 nm, similar to that of ZnS:Mn However the intensity of the peak at 595 nm of ZnS:MneFe3O4 nanoparticles is lower than that of

ZnS:Mn nanoparticles This can be explained by the presence of Fe3O4and SiO2in ZnS:MneFe3O4nanoparticles, which reduces the

inuence of Mn2ỵ ion on PL result These results indicate that

ZnS:MneFe3O4nanoparticles contain ZnS:Mn nanoparticles and

have similar PL properties with ZnS:Mn nanoparticles in visible region, which can be used for labeling application in biomedicine

Fig 5shows magnetization curves measured on the ZnS:Mn, Fe3O4and ZnS:MneFe3O4nanoparticles It can be seen that the

magnetization of ZnS:Mn nanoparticles is very low, of emu/g, compared to those of Fe3O4 and ZnS:MneFe3O4 nanoparticles,

which reaches around 59.4 emu/g and 31.7 emu/g at 13.5 kOe, respectively The fact that the ZnS:MneFe3O4nanoparticles have

lower magnetization can be explained by the presence of ZnS:Mn nanoparticles inside the sample as well as the presence

of the SiO2 cover matrix which does not exhibit magnetism

The ZnS:MneFe3O4 nanoparticles show magnetic properties

similar to Fe3O4 nanoparticles, indicating that the synthesized

ZnS:MneFe3O4nanoparticles contain Fe3O4nanoparticles inside

Fig X-ray patterns of ZnS:Mn, Fe3O4and ZnS:MneFe3O4nanoparticles

Fig FTIR spectra of ZnS:Mn, Fe3O4and ZnS:MneFe3O4nanoparticles

Fig Photoluminescence spectra of ZnS:MneFe3O4 and ZnS:Mn nanoparticles

excited at 335 nm

(4)

These results also support the successful combining of Fe3O4and

ZnS:Mn nanoparticles in SiO2matrix The magnetic properties of

nanoparticles investigated also show that ZnS:MneFe3O4

nano-particles can be used for magnetic delivery, therapies or DNA separating applications in biomedicine

4 Conclusions

ZnS:MneFe3O4 bifunctional nanoparticles were successfully

synthesized from ZnS:Mn and Fe3O4nanoparticles in

biocompat-ible SiO2 matrix using inverse microemulsion method The

bifunctional nanoparticles have photoluminescence similar to ZnS:Mn photoluminescence nanoparticles and magnetic propeties similar to Fe3O4 magnetic nanoparticles, which support their

use in both labeling and separating applications in biomedicine Furthermore, with the biocompartible SiO2 cover matrix, these

nanoparticles can be easily surface-modiﬁed in many biomedicine-application purposes

Acknowledgment

This paper is dedicated to the memory of Peter Brommer He was a good friend of the Vietnamese physicists during the years of cooperation between the Hanoi and Amsterdam Universities With his deep knowledge of 'Magnetism of Metals' he was always ready to assist his colleagues We are grateful for his involvement in the cooperation over a period as long as thirty years

References

[1] G Bao, S Mitragotri, S Tong, Multifunctional nanoparticles for drug delivery and molecular imaging, Ann Rev Biomed Eng 15 (2013) 253e282 [2] M Srinivasan, M Rajabi, Shaker A Mousa, Multifunctional nanomaterials and

their application in drug delivery and cancer therapy, Nanomaterials (2015) 1690e1703

[3] Dao Van Quy, Nguyen Minh Hieu, Pham Thi Tra, Nam Nguyen Hoang, Hai Nguyen Hoang, Son Nguyen Thai, Phan Tuan Nghia, Nguyen Thi Van Anh, Tran Thi Hong, Nguyen Hoang Luong, Synthesis of silica-coated magnetic nanoparticles and application in detection of pathogenic viruses, J Nanomat 2013 (2013) 603940, 6pp

[4] J Liu, W He, L Zhang, Z Zhang, J Zhu, L Yuan, H Chen, Z Cheng, X Zhu, Bifunctional nanoparticles withﬂuorescence and magnetism via surface-initiated AGET ATRP mediated by an iron catalyst, Langmuir 27 (2011) 12684e12692

[5] J Lipka, M Semmler-Behnke, R.A Sperling, A Wenk, S Takenaka, C Schleh, T Kissel, W.J Parak, W.G Kreyling, Biodistribution of PEG-modiﬁed gold nanoparticles following intratracheal instillation and intravenous injection, Biomaterials 31 (2010) 6574e6581

[6] W.S Cho, M Cho, J Jeong, M Choi, B.S Han, H.S Shin, J Hong, B.H Chung, J Jeong, M.H Cho, Size-dependent tissue kinetics of PEG-coated gold nano-particles, Toxicol Appl Pharmacol 245 (2010) 116e123

[7] S Takae, Y Akiyama, H Otsuka, T Nakamura, Y Nagasaki, K Kataoka, Ligand density effect on biorecognition by PEGylated gold nanoparticles: regulated interaction of RCA120lectin with lactose installed to the distal end of tethered

PEG strands on gold surface, Biomacromolecules (2005) 818e824 [8] T Ishi, H Otsuka, K Kataoka, Y Nagasaki, Preparation of functionally

PEGy-lated gold nanoparticles with narrow distribution through autoreduction of auric cation by a -biotinyl-PEG-block-[poly(2-(N,N-dimethylamino)ethyl-mathacrylate)], Langmuir 20 (2004) 561e564

[9] H Khalil, D Mahajan, M Rafailovich, M Gelfer, K Pandya, Synthesis of zer-ovalent nanophase metal particles stabilized with poly(ethylene glycol), Langmuir 20 (2004) 6896e6903

[10] Q Xiao, C Xiao, Synthesis and photoluminescence of water-soluble Mn:ZnS/ ZnS core/shell quantum dots using nucleation-doping strategy, Opt Mater 31 (2008) 455e460

[11] B Pong, B.L Trout, J.Y Lee, Modiﬁed ligand-exchange for efﬁcient solubili-zation of CdSe//ZnS quantum dots in water: a procedure guided by compu-tational studies, Langmuir 24 (2008) 5270e5276

[12] Tran Thi Quynh Hoa, Le Thi Thanh Binh, Le Van Vu, Nguyen Ngoc Long, Vu Thi Hong Hanh, Vu Duc Chinh, Pham Thu Nga, Luminescent ZnS: Mn/thioglycerol and ZnS: Mn/ZnS core/shell nanocrystals: synthesis and characterization, Opt Mater 35 (2012) 136e140

[13] J Lim, R.D Tilton, A Eggeman, S.A Majetich, Design and synthesis of plamonic magnetic nanoparticles, J Magn Magn Mater 311 (2007) 78e83

[14] J Yang, J Cao, L Yang, Y Zhang, Y Wang, X Liu, D Wang, M Wei, M Gao, J Lang, Fabrication and photoluminescence of ZnS: Mn2ỵnanowires/ZnO quantum dots/SiO2heterostructure, J App Phys 108 (2010) 044304 (7pp)

[15] J Aswathy, N.V Seethalekshmy, K.R Hiran, M.R Bindhu, K Manzoor, S.V Nair, D Menon, Mn-doped Zinc Sulphide nanocrystals for immunoﬂuorescent la-beling of epidermal growth factor receptors on cells and clinical tumor tis-sues, Nanotechnology 25 (2014) 445102 (12pp)

[16] S Prijic, G Sersa, Magnetic nanoparticles as targeted delivery systems in oncology, Radiol Oncol 45 (2011) 1e16

[17] Wahajuddin, S Arora, Superparamagnetic iron oxide nanoparticles: magnetic nanoplatforms as drug carriers, Int J Nanomedicine (2012) 3445e3471 [18] J Estelrich, E Escribano, J Queralt, M.A Busquets, Ion oxide nanoparticles for

magnetically-guided and magnetically-responsive drug delivery, Int J Mol Sci 16 (2015) 8070e8101

[19] M.P Marszałł, Application of magnetic nanoparticles in pharmaceutical sci-ences, Pharm Res 28 (2011) 480e483

[20] A del Campo, T Sen, J.P Lellouche, I.J Bruce, Multifunctional magnetite and silica-magnetite nanoparticles: synthesis, surface activation and application in life sciences, J Magn Magn Mater 293 (2005) 33e40

[21] I.J Bruce, J Taylor, M Todd, M.J Davies, E Borioni, C Sangregorio, T Sen, Synthesis, characterisation and application of silica-magnetite nano-composites, J Magn Magn Mater 284 (2004) 145e160

[22] M.E Abrishami, S.M Hosseini, E.A Kakhki, A Kompany, M Ghasemifard, Synthesis and structure of pure and Mn-doped zinc oxide nanoparticles, Internatioanl J Nanosci (2010) 19e28

[23] S Senthilkumaar, K Rajendran, S Banerje, T.K Chini, V Sengodan, Inﬂuence of Mn doping on the microstructure and optical property of ZnO, Mater Sci Semicon Process 11 (2008) 6e12

[24] S Ummartyotin, N Bunnak, J Juntaro, M Sain, H Manuspiya, Synthesis and luminescence properties of ZnS and metal (Mn, Cu)-doped-ZnS ceramic powder, Solid State Sci 14 (2012) 299e304

[25] J.A Lopez, F Gonzalez, F.A Bonilla, G Zambrano, M.E Gomez, Synthesis and characterization of Fe3O4magnetic nanoﬂuid, Rev Latinoam Metal Mater 30

(1) (2010) 60e66

[26] Y.S Li, J.S Church, A.L Woodhead, F Moussa, Preparation and characterization of silica coated iron oxide magnetic nano-particles, Spectrochim Acta Part A 76 (2010) 484e489

[27] Y.H Lien, T.M Wu, Preparation and characterization of thermosensitive polymers grafted onto silica-coated iron oxide nanoparticles, J Colloid Interface Sci 326 (2008) 517e521

[28] G Murugadoss, B Rajamannan, V Ramasamy, G Viruthagiri, Synthesis and characterization of Mn2ỵ-doped ZnS luminescent nanocrystals, J Ovonic Res (2009) 107e116

[29] R Kripal, A.K Gupta, S.K Mishra, R.K Srivastava, A.C Pandey, S.G Prakash, Photoluminescence and photoconductivity of ZnS: Mn2ỵnanoparticles syn-thesized via co-precipitation method, Spectrochim Acta Part A 76 (2010) 523e530

[30] G.H Li, F.H Su, B.S Ma, K Ding, S.J Xu, W Chen, Photoluminescence of doped ZnS nanoparticles under hydrostatic pressure, Phys Stat Sol (b) 241 (2004) 3248e3256

Fig The magnetization curves of ZnS:Mn, Fe3O4and ZnS:MneFe3O4nanoparticles

at room temperature