Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5894_Библиотеки_им_академика_М_И_Перельмана.pdf
3 Topographic Properties ofPEGylated Nanocarriers
97
Fig. 3.19 AFM images of PEG7%-g-PLA rhodamine B-loaded nanocarriers before (a) and after
(b) lyophilization; surface morphology (left, S) and phase image (right, P). (Figure adapted with
permission from Essa et al. (2011) Copyright © 2011 Elsevier)
addition to particle size distribution, SEM can also be used to investigate the aggregation and dispersion of colloidal nanocarriers.
SEM requires specic sample preparation protocols based on the application.
For topographic and morphological investigation, nonconductive samples need to
be coated with a metal like platinum or gold. This not only improves imaging quality by enhancing secondary electron signal but also protects samples from radiation
damage. For any type of characterization, the samples should also be dried, and a
completely dry environment must be ensured in the vacuum chamber.
Most limitations of SEM arise due to its tedious sample preparation requirements. Dehydration of the sample may cause damage in the form of shrinking or
aggregation of particles. Even if solvent removal is not detrimental to a given
98
A. G. Prasad et al.
sample, dehydration will prevent characterization in the native aqueous environment for colloidal suspensions. Similarly, metal coating can obscure the original
topographic features of the specimen. In the context of polymeric nanoparticles like
PEGylated nanocarriers, vacuum conditions can collapse the grafted PEG chains
thereby distorting the topography. Though it is a very valuable tool to characterize
the surface of the nanocarrier, SEM is not suitable for studying the internal structure. In addition to these technical challenges, SEM is also an expensive instrument
to install and maintain.
3.12.1 Application inPEGylated Nanocarriers
Ebbesen and colleagues synthesized PEGylated PLGA nanocarriers using two
methods—surface grafting of PEG chains and as a copolymer. SEM was used to
characterize the size and morphology of nanoparticles. The hydrodynamic diameter
was measured to be in the range of 500–1500nm, and these results were corroborated by dynamic light scattering (DLS) measurements. Figure3.20 shows the SEM
micrographs for (a) non-PEGylated nanocarriers; PEGylated nanocarriers with (b)
30% nonanchoring PEG, (c) 6% PLGA-b-PEG, and (d) 30% PLGA-b-PEG. All
nanocarriers were observed to be polydisperse with a spherical morphology and
smooth topography. Interestingly, PLGA-b-PEG nanocarriers with 6% PEG showed
signicantly larger particles, whereas other PEGylated nanocarriers did not show
any apparent difference in comparison to the blank (0% PEG) nanocarriers (Ebbesen
etal. 2013). In this report, the authors demonstrated the utility of SEM to investigate
the shape, size distribution, and morphology of polymeric nanoparticles.
In another report, Yoncheva etal. developed poly(methyl vinyl ether-co-maleic
anhydride) (PVM/MA) based PEGylated nanocarriers. SEM was used to determine
the shape and morphology of the nanoparticles. As seen in the SEM image in
Fig.3.21, nanoparticles displayed a size of 280–300nm with a spherical morphology. These results agreed with the photon correlation spectroscopy analysis. Based
on this, the authors concluded that grafting the surface with PEG chains had no
signicant inuence on the size of the PEGylated nanocarriers (Yoncheva
etal. 2005).
3.13 Transmission Electron Microscopy
Transmission electron microscopy (TEM) works on a similar principle to that of
SEM.The main difference between the two techniques is the higher voltages of
80–300keV used in TEM.A tungsten or lanthanum hexaboride electric gun emits
high-energy electrons. The electrons are focused through an electromagnetic lens
and the ne beam passes through the specimen. Scattered and transmitted electrons
are detected and the difference in electron densities produces 2-D images with contrast on a phosphorescent screen. The brightness of the image is directly related to
the fraction of transmitted electrons.
3 Topographic Properties ofPEGylated Nanocarriers
99
Fig. 3.20 SEM images of nanocarriers: (a) 0% (blank), (b) 30% nonanchoring PEG, (c) 6%
PLGA-b-PEG, and (d) 30% PLGA-b-PEG. (Figure adapted with permission from Ebbesen et al.
(2013) Copyright © 2013, Springer Nature)
TEM can be used to determine the size distribution, morphology, and atomic
structure of the sample at ultra-high resolution. Elemental analysis is also possible
if emitted X-rays are detected or when combined with spectroscopic techniques. In
addition to the topography of the sample, TEM is also routinely used to characterize
interactions of nanoparticles with biological milieu shedding light on aspects such
as uptake and localization in cells. Cryo-TEM is particularly apt for such applications wherein aqueous dispersion of particles can be observed to analyze them in
their native environment.
As is the case with SEM, sample preparation for TEM is cumbersome. Polymeric
and other nanoparticles are drop-casted before immobilizing the dried specimen
onto a copper grid coated with a carbon lm. This is followed by the negative staining with phosphotungstic acid, uranyl acetate, or ammonium molybdate solution.
Negative staining is important to ensure an opaque background that enables the
translucent specimen to be viewed easily. TEM requires the sample to be thin for the
100
Fig. 3.21 SEM images of
PVM/MA-based
PEGylated nanocarriers
(Figure adapted with
permission from Yoncheva
et al. (2005) Copyright ©
2004 Elsevier).
A. G. Prasad et al.
beam to get transmitted through it. If the sample is larger than ~500nm, ultramicrotomy or a focused ion beam is necessary.
Though it is the most preferred electron microscopy technique, TEM suffers
from several limitations as follows. The instrumentation and maintenance of equipment are not only expensive but it also requires highly trained users. All drawbacks
of SEM apply to TEM as well. As it is operated in vacuum conditions, the samples
must be completely dry. Drying protocols can result in sample damage or distort the
topography and produce artifacts at best. This is a major challenge, particularly for
the characterization of polymeric nanocarriers. This can be addressed by spiking the
staining solution with a small concentration of glucose. Interaction with high-energy
scattered electrons may also damage the sample. This can be prevented by preparing
samples that are thinner than 500nm.
3.13.1 Application inPEGylated Nanocarriers
Ana Vila etal. fabricated PEGylated poly (lactic acid)-poly (ethylene glycol) (PLA–
PEG) nanoparticles and studied the impact of PEG coating density on transport
across the mucosal membrane. PLA–PEG copolymers of different molecular
weights were used to form the nanocarriers through nanoprecipitation and multiple
emulsion techniques. The authors used TEM to investigate the topography and morphology of nanocarriers. TEM images (Fig.3.22) showed that particles synthesized
with different molecular weights of PEG displayed no signicant differences in
appearance for a given preparation technique. However, different preparation techniques inuenced changes in the size and morphology of nanocarriers. As seen in
3 Topographic Properties ofPEGylated Nanocarriers
101
Fig. 3.22 TEM images of nanocarriers prepared with PLA–PEG copolymers of 37kDa weight,
using different preparation techniques. (Figure adapted with permission from Vila et al. (2004)
Copyright © 2004 Published by Elsevier)
the image, the emulsion technique formed particles that were more spherical than
those prepared using the nanoprecipitation technique (Vila etal. 2004). This report
demonstrates how TEM can be used to not only study the morphology of PEGylated
nanocarriers but also compare different preparation techniques.
Carl Walkey and colleagues prepared gold nanoparticles of different sizes and
studied the impact of size and PEG coating on serum protein adsorption and macrophage uptake. The authors used TEM to prove that PEGylated nanocarriers localized in the endosomes are independent of PEG grafting density. Figure3.23 shows
that non-PEGylated carriers formed dense aggregates, whereas PEGylated carriers
were well dispersed (Walkey etal. 2012). TEM can therefore be used to analyze
biological samples and study interactions of nanocarriers with cells and serum
proteins.
102
Fig. 3.23 TEM images of nanocarriers with PEG at 0, 0.48, and 0.96PEG/nm2. (Figure adapted
with permission from Walkey et al. (2012) Copyright © 2011 American Chemical Society)
A. G. Prasad et al.
3.14 Conclusion
Surface characterization is a very essential tool to probe the surface topography and
morphology of nanomaterials. As interfacial parameters dictate the stability and
properties of PEGylated nanocarriers, there is a need to determine the critical attributes accurately and precisely. Several spectroscopic techniques have been routinely applied to investigate the surface topography of nanocarriers. Modications
to the existing methods can provide useful information about the conformation and
arrangement of PEG chains. Advanced electron microscopic techniques and AFM
can achieve high-resolution topographic images of the core of the nanocarriers,
whereas other methods like thermogravimetric and calorimetric analysis provide
vital complementary information about the tethered PEG chains. As all techniques
suffer from specic limitations with respect to sample preparation and method
applicability, combining two or three tools would be the most effective approach to
characterize the topographic features of PEGylated nanocarriers.
References
Alexis F etal (2008) Factors affecting the clearance and biodistribution of polymeric nanopar-
ticles. Mol Pharm 5(4):505–515
Allard-Vannier E et al (2017) Folic acid-capped PEGylated magnetic nanoparticles enter can-
cer cells mostly via clathrin-dependent endocytosis. Biochim Biophys Acta Gen Subj
1861(6):1578–1586
Ara MN etal (2014) An aptamer ligand based liposomal nanocarrier system that targets tumor
endothelial cells. Biomaterials 35(25):7110–7120
Backmann N et al (2010) Sensing surface PEGylation with microcantilevers. Beilstein J
Nanotechnol 1:3–13
Baer DR et al (2010) Application of surface chemical analysis tools for characterization of
nanoparticles. Anal Bioanal Chem 396(3):983–1002
Bailo E, Deckert V (2008) Tip-enhanced Raman scattering. Chem Soc Rev 37(5):921–930
Butterworth MD, Illum L, Davis SS (2001) Preparation of ultrane silica- and PEG-coated mag-
netite particles. Colloids Surf A Physicochem Eng Asp 179(1):93–102
Chen H etal (2016) DUP1 peptide modied micelle efciently targeted delivery paclitaxel and
enhance mitochondrial apoptosis on PSMA-negative prostate cancer cells. SpringerPlus 5:362
3 Topographic Properties ofPEGylated Nanocarriers
Coelho SC etal (2015) Structural characterization of functionalized gold nanoparticles for drug
delivery in cancer therapy: a NMR based approach. Phys Chem Chem Phys 17(29):18971–18979
Conte C etal (2019) Surface exposure of PEG and amines on biodegradable nanoparticles as a
strategy to tune their interaction with protein-rich biological media. Nanomaterials (Basel)
9(10):1354
Corbierre MK, Cameron NS, Lennox RB (2004) Polymer-stabilized gold nanoparticles with high
grafting densities. Langmuir 20(7):2867–2873
Damodaran VB etal (2010) Conformational studies of covalently grafted poly(ethylene glycol) on
modied solid matrices using X-ray photoelectron spectroscopy. Langmuir 26(10):7299–7306
Dazzi A etal (2005) Local infrared microspectroscopy with subwavelength spatial resolution with
an atomic force microscope tip used as a photothermal sensor. Opt Lett 30(18):2388–2390
Ebadi M etal (2019) Synthesis and properties of magnetic nanotheranostics coated with polyethyl-
ene glycol/5-uorouracil/layered double hydroxide. Int J Nanomedicine 14:6661–6678
Ebbesen MF etal (2013) Surface analysis of PEGylated nano-shields on nanoparticles installed by
hydrophobic anchors. Pharm Res 30(7):1758–1767
Essa S, Rabanel JM, Hildgen P (2010) Effect of polyethylene glycol (PEG) chain organization on
the physicochemical properties of poly(D, L-lactide) (PLA) based nanoparticles. Eur J Pharm
Biopharm 75(2):96–106
Essa S, Rabanel JM, Hildgen P (2011) Characterization of rhodamine loaded PEG-g-PLA nanopar-
ticles (NPs): effect of poly(ethylene glycol) grafting density. Int J Pharm 411(1–2):178–187
Garcia-Fuentes M etal (2004) Application of NMR spectroscopy to the characterization of PEG-
stabilized lipid nanoparticles. Langmuir 20(20):8839–8845
Gref R et al (1994) Biodegradable long-circulating polymeric nanospheres. Science
263(5153):1600–1603
Gref R et al (2001) Development and characterization of CyA-loaded poly(lactic acid)-
poly(ethylene glycol)PEG micro- and nanoparticles. Comparison with conventional PLA par-
ticulate carriers. Eur J Pharm Biopharm 51(2):111–118
Groves P etal (2004) Diffusion ordered spectroscopy as a complement to size exclusion chroma-
tography in oligosaccharide analysis. Glycobiology 14(5):451–456
Hinterwirth H etal (2013) Quantifying thiol ligand density of self-assembled monolayers on gold
nanoparticles by inductively coupled plasma-mass spectrometry. ACS Nano 7(2):1129–1136
Hooftman A, O'Neill LAJ (2022) Nanoparticle asymmetry shapes an immune response. Nature
601(7893):323–325
Iranpour S etal (2021) Improving anti-cancer drug delivery performance of magnetic mesoporous
silica nanocarriers for more efcient colorectal cancer therapy. J Nanobiotechnol 19(1):314
Jokerst JV etal (2011) Nanoparticle PEGylation for imaging and therapy. Nanomedicine (Lond)
6(4):715–728
Joudeh N, Linke D (2022) Nanoparticle classication, physicochemical properties, characteriza-
tion, and applications: a comprehensive review for biologists. J Nanobiotechnol 20(1):262
Karim ME, Chowdhury EH (2022) PEGylated strontium sulte nanoparticles with spontaneously
formed surface-embedded protein Corona restrict off-target distribution and accelerate breast
tumour-selective delivery of siRNA.J Funct Biomater 13(4)
Katuwavila NP etal (2020) Graphene oxide-based nanocomposite for sustained release of cepha-
lexin. J Pharm Sci 109(2):1130–1135
Larson TA, Joshi PP, Sokolov K (2012) Preventing protein adsorption and macrophage uptake of
gold nanoparticles via a hydrophobic shield. ACS Nano 6(10):9182–9190
León A etal (2017) FTIR and Raman characterization of TiO2 nanoparticles coated with polyeth-
ylene glycol as carrier for 2-Methoxyestradiol. Appl Sci 7(1):49
Levin CS et al (2006) Determining the conformation of thiolated poly(ethylene glycol) on
au nanoshells by surface-enhanced Raman scattering spectroscopic assay. Anal Chem
78(10):3277–3281
Lu J etal (2019) A non-sacricial method for the quantication of poly(ethylene glycol) grafting
density on gold nanoparticles for applications in nanomedicine. Chem Sci 10(7):2067–2074
103
104
Maccarini M etal (2010) Characterization of poly(ethylene oxide)-capped gold nanoparticles in
water by means of transmission electron microscopy, thermogravimetric analysis, mass den-
sity, and small angle scattering. J Phys Chem C 114(15):6937
Maghsoudi S etal (2023) Development of doxorubicin-encapsulated magnetic liposome@PEG for
treatment of breast cancer in BALB/c mice. Drug Deliv Transl Res 13:2589
Manseld E etal (2014) Determination of nanoparticle surface coatings and nanoparticle purity
using microscale thermogravimetric analysis. Anal Chem 86(3):1478–1484
Mathurin J et al (2018) How to unravel the chemical structure and component localization
of individual drug-loaded polymeric nanoparticles by using tapping AFM-IR. Analyst
143(24):5940–5949
Mitchell MJ et al (2021) Engineering precision nanoparticles for drug delivery. Nat Rev Drug
Discov 20(2):101–124
Mohamed M etal (2019) PEGylated liposomes: immunological responses. Sci Technol Adv Mater
20(1):710–724
Mourdikoudis S, Pallares RM, Thanh NTK (2018) Characterization techniques for nanopar-
ticles: comparison and complementarity upon studying nanoparticle properties. Nanoscale
10(27):12871–12934
Pelaz B etal (2015) Surface functionalization of nanoparticles with polyethylene glycol: effects on
protein adsorption and cellular uptake. ACS Nano 9(7):6996–7008
Peleg-Shulman T etal (2004) Reversible PEGylation: a novel technology to release native inter-
feron alpha2 over a prolonged time period. J Med Chem 47(20):4897–4904
Prasad A etal (2021) Transport-driven engineering of liposomes for delivery of α-particle radio-
therapy to solid tumors: effect on inhibition of tumor progression and onset delay of spontane-
ous metastases. Eur J Nucl Med Mol Imaging 48(13):4246–4258
Rabanel JM, Hildgen P, Banquy X (2014) Assessment of PEG on polymeric particles surface, a
key step in drug carrier translation. J Control Release 185:71–87
Rabanel JM etal (2015) Effect of the polymer architecture on the structural and biophysical prop-
erties of PEG-PLA nanoparticles. ACS Appl Mater Interfaces 7(19):10374–10385
Retout M etal (2019) Limits of thiol chemistry revealed by quantitative analysis of mixed layers
of thiolated-PEG ligands grafted onto gold nanoparticles. J Colloid Interface Sci 557:807–815
Sacchetti C etal (2013) Surface polyethylene glycol conformation inuences the protein corona of
polyethylene glycol-modied single-walled carbon nanotubes: potential implications on bio-
logical performance. ACS Nano 7(3):1974–1989
Sant S, Poulin S, Hildgen P (2008) Effect of polymer architecture on surface properties, plasma
protein adsorption, and cellular interactions of pegylated nanoparticles. J Biomed Mater Res
A 87(4):885–895
Sebby KB, Manseld E (2015) Determination of the surface density of polyethylene glycol on
gold nanoparticles by use of microscale thermogravimetric analysis. Anal Bioanal Chem
407(10):2913–2922
Shi L etal (2021) Effects of polyethylene glycol on the surface of nanoparticles for targeted drug
delivery. Nanoscale 13(24):10748–10764
Stras S etal (2020) Growth of metastatic triple-negative breast cancer is inhibited by deep tumor-
penetrating and slow tumor-clearing chemotherapy: the case of tumor-adhering liposomes with
interstitial drug release. Mol Pharm 17(1):118–131
Suk JS et al (2016) PEGylation as a strategy for improving nanoparticle-based drug and gene
delivery. Adv Drug Deliv Rev 99:28–51
Swierczewska M, Lee KC, Lee S (2015) What is the future of PEGylated therapies? Expert Opin
Emerg Drugs 20(4):531–536
Takechi-Haraya Y etal (2022) Current status and challenges of analytical methods for evaluation
of size and surface modication of nanoparticle-based drug formulations. AAPS PharmSciTech
23(5):150
Vernooij EA etal (1999) 1H NMR quantication of poly(ethylene glycol)-phosphatidylethanol-
amine in phospholipid mixtures. Pharm Res 16(10):1658–1661
A. G. Prasad et al.
3 Topographic Properties ofPEGylated Nanocarriers
Vila A etal (2004) Transport of PLA-PEG particles across the nasal mucosa: effect of particle size
and PEG coating density. J Control Release 98(2):231–244
Vogeli B (2014) The nuclear Overhauser effect from a quantitative perspective. Prog Nucl Magn
Reson Spectrosc 78:1–46
Walkey CD etal (2012) Nanoparticle size and surface chemistry determine serum protein adsorp-
tion and macrophage uptake. J Am Chem Soc 134(4):2139–2147
Xu Q etal (2015) Impact of surface polyethylene glycol (PEG) density on biodegradable nanopar-
ticle transport in mucus exvivo and distribution invivo. ACS Nano 9(9):9217–9227
Yoncheva K, Lizarraga E, Irache JM (2005) Pegylated nanoparticles based on poly(methyl vinyl
ether-co-maleic anhydride): preparation and evaluation of their bioadhesive properties. Eur J
Pharm Sci 24(5):411–419
Zelepukin IV etal (2020) Fast processes of nanoparticle blood clearance: comprehensive study. J
Control Release 326:181–191
Zhang Z etal (2016) Tip-enhanced Raman spectroscopy. Anal Chem 88(19):9328–9346
Zhu GH, Gray ABC, Patra HK (2022) Nanomedicine: controlling nanoparticle clearance for trans-
lational success. Trends Pharmacol Sci 43(9):709–711
Zolnik BS etal (2010) Nanoparticles and the immune system. Endocrinology 151(2):458–465
105
