Preparation of polylysine-modified superparamagnetic iron oxide nanoparticles

doi:10.1016/j.jmmm.2014.08.040

Journal of Magnetism and Magnetic Materials

Volume 374, 15 January 2015, Pages 205-208

https://doi.org/10.1016/j.jmmm.2014.08.040 Get rights and content

Highlights

●
Hydrophilic PEG-SPIONs were synthesized by a thermal decomposition approach.
●
The PEG-SPIONs were successfully coated with PLL.
●
PEG-SPIONs and PLL/PEG-SPIONs have small hydrodynamic sizes.
●
Both PEG-SPIONs and PLL/PEG-SPIONs showed superparamagnetic behavior at 300 K.

Abstract

Polylysine (PLL) coated iron oxide nanoparticles (SPIONs) have potential in biomedical application. In the present work PEG coated SPIONs (PEG-SPIONs) with the particle size of 9.4±1.4 nm were synthesized by thermal decomposition of Fe(acac)₃ in PEG, and then coated with PLL (PLL/PEG-SPIONs). The PEG-SPIONs and PLL/PEG-SPIONs were superparamagnetic with the saturation magnetization of 53 and 44 emu/g, respectively. The hydrodynamic diameter of PEG-SPIONs in deionized water was 18.8 nm, which increased to 21.3−28.2 nm after mixing with different amount of PLL. The zeta potentials of PLL/PEG-SPIONs were −8.9 − −3.4 mV which were changing with time. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses indicated that PLL was attached to the PEG-SPIONs.

Introduction

PEG-SPIONs are coated with organic polymers, biomolecules and inorganic materials via the routes such as surface polymerization, surface chemical ligation and adsorption deposition [1]. They are widely used in in vitro [2], [3] and in vivo [4], [5] biomedical applications. Lysine is one of the eight essential amino acids [6]. With good biodegradability and biocompatibility, PLL are proved to be excellent polymeric gene carriers [7]. Grafted with copolymers of PLL and PEG, polymer-DNA condensates had been shown to combine low cytotoxicity, stealth properties and high transfection efficiency in COS-7 cells (African green monkey kidney cells), suggesting that they were a promising tool for effective transport and delivery of therapeutic DNA [8]. PLL that was commonly used to enhance cell adhesion to the surface of a culture dish in in vitro cell cultivation was investigated as a prospective vehicle for iron oxide nanoparticle transport into cells [9]. PLL had been used to facilitate dendritic cell uptake of SPIONs [10]. PLL modified SPIONs were utilized to label the cancer stem cells derived from U251 glioblastoma multiforme and were further used to treat targeted glioblastoma cells [11]. Therefore, PLL/PEG-SPIONs provide enormous potential for biologists. In the present work, the PEG-SPIONs were synthesized by thermal decomposition of the Fe(acac)₃ in PEG, then the PEG-SPIONs were coated with PLL and their properties were investigated for further application.

Section snippets

Materials

Iron(III) acetylacetonate (Fe(acac)₃, 98%) was purchased from Tokyo Kasei Kogyo Co., Ltd. (Tokyo, Japan). Poly(ethylene glycol) (PEG, M_w=1000, 95%), toluene (99%), acetone (99%) were purchased from Xilong Chemistry Co., Ltd. (Shantou, China). Polylysine (PLL, M_w=5000) was provided by Guilin Peptide Technology Co., Ltd. (Guilin, China). All the reagents were used without further purification.

Preparation of PLL modified PEG-SPIONs

In a typical process, the PEG (15 g) was dissolved in a three-neck round bottom flask with vigorous

Results and discussion

Fig. 1 shows the TEM image with size distribution of PEG-SPIONs synthesized by thermal decomposition of Fe(acac)₃ in PEG at 260 °C, the average size of SPIONs are 9.4±1.4 nm, which was measured and calculated using the software “Image J”. The XRD pattern of the sample inserted in Fig. 1 is matching well with the standard XRD pattern for magnetite (JCPDS File no. 01-088-0315). The peaks with 2θ values of 30.09^ο, 35.44^ο, 43.07^ο, 53.43^ο, 56.96^ο, 62.55^ο and 74.00^ο correspond to the crystal planes (2 2

Conclusions

The PEG-SPIONs were prepared by thermal decomposition of Fe(acac)₃ in PEG, and were modified with PLL. The FTIR spectra and the survey XPS spectra of the PLL/PEG-SPIONs indicate that the PEG-SPIONs are successfully coated with PLL. The PEG-SPIONs and PLL/PEG-SPIONs are all superparamagnetic and with hydrodynamic sizes smaller than 40 nm. PEG-SPIONs are modified with PLL through hydrogen bonds, and the zeta potential of PLL/PEG-SPIONs was changing with time probably because of the changed

Acknowledgment

This work was supported by the National Natural Science Foundation of China (No.51162003).

References (32)

R.A. Bini et al.
J. Magn. Magn. Mater.
(2012)
B. Zhang et al.
Biomaterials
(2013)
K. Peldschus et al.
Magn. Reson. Imaging
(2010)
K. Tsuchiya et al.
Eur. J. Radiol.
(2013)
H.Y. Tian et al.
J. Control. Release
(2013)
M. Thiersch et al.
Biomaterials
(2013)
S. Toki et al.
Nanomed. Nanotechnol. Biol. Med.
(2013)
X.Q. Wang et al.
Biomaterials
(2012)
L. Minati et al.
Appl. Surf. Sci.
(2011)
X.L. Ling et al.
Colloid. Surface. A
(2014)

R.C. Oliveira et al.

Chem. Eng. J.

(2014)

T. Liu et al.

Acta Biomater.

(2014)

M.Q. Tan et al.

Talanta

(2013)

C. Gao et al.

Food Hydrocolloids

(2014)

L.N. Geng et al.

Mater. Res. Bull.

(2013)

Z.J. Tu et al.

Colloid. Surface. A

(2013)

Cited by (28)

Poly-L-lysine-modified with ferrocene to obtain a redox polymer for mediated glucose biosensor application
2022, Bioelectrochemistry
Citation Excerpt :
νC-H 2600 cm−1 and 3000 cm−1 correspond to OH-acid stretching, νC = O and νC-O at 1649 cm−1 and 1286 cm−1, while a peak at 1459 cm−1 corresponding to aromatic bond C = C and at 509 cm−1 describes νFe-C. While the FTIR for poly-L-lysine (Fig. 1-A) showed a wide and long peak between 3600 cm−1 and 3058 cm−1, suggesting the overlap peaks of amine –NH2, νN-H and hydroxyl νO-H groups, the broad and prominent peak at 1636 cm−1 corresponds to the stretching vibrations of the νC = O and νC–N bonds of the amide groups [43]. The result of the anchoring of FcCOOH with PLL (Fig. 1-C) presents a combination of peaks showing νC-H, νC = O, νC-O, νC = C, and νFe-C bonds at 2776 cm−1, 3339 cm−1, 1636 cm−1, 1256 cm−1 and 495 cm−1, respectively.
Ferrocene-based polymers as redox mediators are considered versatile and important in the study of glucose biosensors. Poly-L-lysine (PLL), as a cationic polymer, possesses good properties including biocompatibility, biodegradation and water solubility. In this work, PLL was modified with ferrocene carboxylate in a very simple way by activating the carboxyl group of Fc, which reacted with the amino groups of the polymer. The resulting product was analysed by FTIR. Performance as a redox mediator (Fc-PLL) with the enzyme glucose oxidase was tested by cyclic voltammetry and showed an increase in the oxidation current in the presence of glucose in PBS pH 7.4. Additionally, performance as a biosensor was evaluated by amperometry and gave a linear range of 0–10 mM, a limit of detection of 23 μM, a sensitivity of 6.55 μA/cm² mM and high selectivity. To evaluate the charged regions of Fc-PLL/GOx on the electrode surface, analysis by scanning electrochemical microscopy showed remarkable activity. The Fc-PLL redox polymer as a glucose biosensor has been well accepted as this kind of material, and the results showed remarkable activity as an electron transfer mediator between the redox polymer and the GOx enzyme.
Poly-L-lysine-functionalized magnetic beads combined with polymerase chain reaction for the detection of Staphylococcus aureus and Escherichia coli O157:H7 in milk
2021, Journal of Dairy Science
Rapid and credible detection of pathogens is essential to prevent and control outbreaks of foodborne diseases. In this study, a poly-l-lysine-functionalized magnetic beads (PLL-MB) strategy combined with a PCR assay was established to detect Staphylococcus aureus. We also detected Escherichia coli O157:H7 to further verify the strategy for gram-negative bacteria detection. Poly-l-lysine has strong positive charges because of its amino groups, which can conjugate with the carboxyl of carboxyl magnetic beads. Furthermore, it can be used to combine with bacteria through electrostatic adsorption. Under optimum conditions, the developed PLL-MB complexes showed 90% capture efficiency in phosphate-buffered saline and 85% capture efficiency in milk for S. aureus detection. The limit of detection of the PLL-MB-PCR assay was 10² cfu/mL (1.8 × 10² cfu/mL for S. aureus and 7 × 10² cfu/mL for E. coli O157:H7) in phosphate-buffered saline and milk samples. The whole assay can be performed within 4 h. The proposed strategy showed a lower limit of detection when compared with the conventional PCR assay without enrichment. In addition, this method exhibited the advantages of a high-efficient, cost-efficient, and simple operation, indicating its potential applications in foodborne pathogen detection.
The distribution of the iron oxide nanoparticles modified with polyethylene glycol in rat brains
2021, Materials Chemistry and Physics
Citation Excerpt :
The distribution of PEG-SPIONs in the rat brain was studied after injecting them into the rat substantia nigra, the nanoparticles were mostly found around the axonal membrane and dendritic membrane. Water-soluble PEG-SPIONs were synthesized by thermal decomposition method [20,21]. The synthesis detail and the characterization methods for the nanoparticles can be found in the Supporting Information.
The distribution characteristics of nanoparticles associated with cells are crucial to many applications, including magnetic hyperthermia, drug carriers, etc. To clarify the locations when nanoparticles enter the in vivo environments is a necessity. In this work, superparamagnetic iron oxide nanoparticles modified with polyethylene glycol (PEG-SPIONs) were prepared by high temperature thermal decomposition method, and then stereotaxic injections of PEG-SPIONs into the substantia nigra of Sprague-Dawley rats were performed. The distribution of nanoparticles in rat brain was observed by inductively coupled plasma emission spectrometer (ICP-OES) and transmission electron microscopy (TEM). It was found that the iron contents were higher in the olfactory bulb, temporal lobe, prefrontal cortex and thalamus after the injection of PEG-SPIONs for 24 h and 7 days, PEG-SPIONs were mostly distributed around the axonal membrane and dendritic membrane, and a small amount were distributed near the myelin membrane and mitochondrial membrane, which can be ascribed to the nature of PEG, the hydration size and Zeta potential of PEG-SPIONs. Along with their magnetocaloric effect the PEG-SPIONs have potential to act on the ion channels on the cell membrane under an alternating current magnetic field.
Epsilon-poly-L-lysine decorated ordered mesoporous silica contributes to the synergistic antifungal effect and enhanced solubility of a lipophilic drug
2019, Materials Science and Engineering C
Citation Excerpt :
The peaks at 956 cm−1 and 456 cm−1 were assigned to SiOH band and anti-symmetric stretching vibration of the SiOSi band, respectively [44]. Two peaks around 1645 and 1551 cm−1 corresponded to the amide groups of EPL, which originated from the stretching vibrations of the NH, CO and CN bonds of the amide groups in the EPL [45]. And the triazol-3-one CO stretch at 1694 cm−1 was from ITZ [46], which revealed that ITZ was well immobilized in the SBA-15/EPL matrix.
The emergence of drug-resistant fungal strains remains a severe threat for the public health, which prompts strict restrictions on the uses of antifungal drugs. However, the majority of lipophilic fungistatic agents are poorly water soluble with a low oral adsorption characteristic posing challenges for the precise prescriptions. In this study, a natural antimicrobial cationic peptide of epsilon-poly-l-lysine (EPL) decorated ordered mesoporous silica (SBA-15) was facilely prepared for the efficient loading of antifungal itraconazole (ITZ) drugs. The characterized mesoporous SBA-15/EPL/ITZ composite exhibited remarkable antifungal performance against Aspergillus fumigatus as a model mold, which was attributed to synergistic antifungal activities of ITZ and EPL in the mesopores. Moreover, the in vitro release behaviors of ITZ in the composite nanoexcipients both in simulated gastric fluid and fasted state simulated intestinal fluid were studied. The observed release kinetics of ITZ demonstrated a contributing role of SBA-15/EPL to enhance the solubility of ITZ and thereby may promote its flux across the gastrointestinal epithelium, which is beneficial for the absorption of drugs. Additionally, SBA-15/EPL/ITZ composites showed desirable biocompatibility toward mammalian red blood cells, human cervical cancer cells (Hela) and human embryonic kidney cells (HEK-293T). Furthermore, the pharmacokinetic profiles of obtained nano-formulations were assessed in rats, among which the improved adsorption of SBA-15/EPL/ITZ composites (AUC_{0–24h sum}: 8381.7 nM·h) was identified compared with that of pure ITZ (525.1 nM·h) and the commercial drug of Sporanox (7516.6 nM·h). Collectively, the prepared SBA-15/EPL/ITZ provides an ecofriendly and integrated nanocomposite with enhanced solubility of lipophilic drugs to combat proliferations of infectious fungi.
Hemocompatible ɛ-polylysine-heparin microparticles: A platform for detecting triglycerides in whole blood
2018, Biosensors and Bioelectronics
Citation Excerpt :
In curve b, broad peak in the range from 3600 to 3000 cm–1 was attributed to the overlap peaks of amine (–NH2, –NH–) and hydroxyl (–OH) groups stretching vibrations. It could also be found that two shoulders near 1600 cm−1 corresponded to the strong Amide I (~ 1669 cm−1) and Amide II (~ 1498 cm−1) absorbance bands of ɛ-PL (Yang et al., 2015; Tam et al., 2005). After the occurrence of electrostatic self-assembly between Hep and ɛ-PL, all the characteristic peaks of the two substances were retained, this showed that ɛ-PL-Hep microparticles were successfully formed.
Triglycerides are clinically important marker for atherosclerosis, heart disease and hypertension. Here, a platform for detecting triglycerides in whole blood directly was developed based on hemocompatible ɛ-polylysine-heparin microparticles. The obtained products of ɛ-polylysine-heparin microparticles were characterized by fourier transform infrared (FT-IR) spectra, transmission electron microscopy (TEM) and ζ-potential. Moreover, the blood compatibility of ɛ-polylysine-heparin microparticles was characterized by in vitro coagulation tests, hemolysis assay and whole blood adhesion tests. Considering of uniform particle size, good dispersibility and moderate long-term anticoagulation capability of the microparticles, a Lipase-(ɛ-polylysine-heparin)-glassy carbon electrode (GCE) was constructed to detect triglycerides. The proposed biosensor had good electrocatalytic activity towards triglycerides, in which case the sensitivity was 0.40 μA mg⁻¹ dL cm⁻² and the detection limit was 4.67 mg dL⁻¹ (S/N = 3). Meanwhile, the Lipase-(ɛ-polylysine-heparin)-GCE electrode had strong anti-interference ability as well as a long shelf-life. Moreover, for the detection of triglycerides in whole blood directly, the detection limit was as low as 5.18 mg dL⁻¹. The new constructed platform is suitable for detecting triglycerides in whole blood directly, which provides new analytical systems for clinical illness diagnosis.
A method for determination of [Fe<sup>3+</sup>]/[Fe<sup>2+</sup>] ratio in superparamagnetic iron oxide
2017, Journal of Magnetism and Magnetic Materials
Superparamagnetic iron oxide nanoparticles (SPION), as a kind of nanophase materials, are widely used in biomedical application, such as magnetic resonance imaging (MRI), drug delivery, and magnetic field assisted therapy. The magnetic property of SPION has close connection with its crystal structure, namely it is related to the ratio of Fe³⁺ and Fe²⁺ which form the SPION. So a simple way to determine the content of the Fe³⁺ and Fe²⁺ is important for researching the property of SPION. This review covers a method for determination of the Fe³⁺ and Fe²⁺ ratio in SPION by UV–vis spectrophotometry based the reaction of Fe²⁺ and 1,10-phenanthroline. The standard curve of Fe with R² = 0.9999 is used for determination the content of Fe²⁺ and total iron with 2.5 mL 0.01% (w/v) SPION digested by HCl, pH = 4.30 HOAc-NaAc buffer 10 mL, 0.01% (w/v) 1,10-phenanthroline 5 mL and 10% (w/v) ascorbic acid 1 mL for total iron determine independently. But the presence of Fe³⁺ interfere with obtaining the actual value of Fe²⁺ (the error close to 9%). We designed a calibration curve to eliminate the error by devising a series of solution of different ratio of [Fe³⁺]/[Fe²⁺], and obtain the calibration curve. Through the calibration curve, the error between the measured value and the actual value can be reduced to 0.4%. The R² of linearity of the method is 0.99441 and 0.99929 for Fe²⁺ and total iron respectively. The error of accuracy of recovery and precision of inter-day and intra-day are both lower than 2%, which can prove the reliability of the determination method.

View all citing articles on Scopus

View full text

Preparation of polylysine-modified superparamagnetic iron oxide nanoparticles

Highlights

Abstract

Introduction

Section snippets

Materials

Preparation of PLL modified PEG-SPIONs

Results and discussion

Conclusions

Acknowledgment

J. Magn. Magn. Mater.

Biomaterials

Magn. Reson. Imaging

Eur. J. Radiol.

J. Control. Release

Biomaterials

Nanomed. Nanotechnol. Biol. Med.

Biomaterials

Appl. Surf. Sci.

Colloid. Surface. A

Chem. Eng. J.

Acta Biomater.

Talanta

Food Hydrocolloids

Mater. Res. Bull.

Colloid. Surface. A