It has been reported that the hydration state of biocompatible polymers, such as poly(ethylene glycol) (PEG), affects their bioinertness. PEGylated dendrimers have been studied for use as drug carriers. In our previous study, the hydration behaviors of PEG and PEGylated dendrimers were analyzed using differential scanning calorimetry (DSC) to investigate the relationship between hydration and in vivo behaviors. In this study, the hydration behaviors of PEG and PEGylated dendrimer were analyzed using X-ray diffraction (XRD) and infrared (IR) spectroscopy. According to the XRD analysis, ice was formed and melted in the PEG/water mixture with a 20% water content below 0 °C during the heating process; however, PEG crystals were formed in the PEG/water mixture containing 70% water. The XRD and IR results of the PEGylated dendrimer/water mixture were similar to those of the PEG/water system containing 70% water. Our IR spectral studies indicated that the hydration state of the PEGylated dendrimer was different from that of PEG containing 20% water. These results suggested that a comprehensive study is important for the analysis of such eutectic mixtures of PEG compounds and water.
This is a preview of subscription content, access via your institution
Subscribe to this journal
Receive 12 print issues and online access
$259.00 per year
only $21.58 per issue
Rent or buy this article
Prices vary by article type
Prices may be subject to local taxes which are calculated during checkout
Bag MA, Valenzuela LM. Impact of the hydration states of polymers on their hemocompatibility for medical applications: a review. Int J Mol Sci. 2017;18:1422–52.
Tanaka M, Hayashi T, Morita S. The roles of water molecules at the biointerface of medical polymers. Polym J. 2013;45:701–10.
Tanaka M, Morita S, Hayashi T. Role of interfacial water in determining the interaction of proteins and cells with hydrated materials. Colloids Surf B. 2021;198:111449.
Chen S, Li L, Zhao C, Zheng J. Surface hydration: Principles and applications toward low-fouling/nonfouling biomaterials. Polymer. 2010;51:5283–93.
Veronese FM, Pasut G. PEGylation, successful approach to drug delivery. Drug Discov Today. 2005;10:1451–58.
Suk JS, Xu Q, Kim N, Hanes J, Ensign LM. PEGylation as a strategy for improving nanoparticle-based drug and gene delivery. Adv Drug Deliv. 2016;99:28–51.
Fang J, Nakamura H, Maeda H. The EPR effect: unique features of tumor blood vessels for drug delivery, factors involved, and limitations and augmentation of the effect. Adv. Drug Deliv. 2011;63:136–51.
Maruyama K. Intracellular targeting delivery of liposomal drugs to solid tumors based on EPR effects. Adv Drug Deliv. 2011;63:161–9.
Cabral H, Kataoka K. Progress of drug-loaded polymeric micelles into clinical studies. J Control Release. 2014;190:465–76.
Luong D, Kesharwani P, Deshmukh R, Amin MCIM, Gupta U, Greish K, et al. PEGylated PAMAM dendrimers: enhancing efficacy and mitigating toxicity for effective anticancer drug and gene delivery. Acta Biomater. 2016;43:14–29.
Sherje AP, Jadhav M, Dravyakar BR, Kadam D. Dendrimers: a versatile nanocarrier for drug delivery and targeting. Int J Pharm. 2018;548:707–20.
Tomalia DA, Nixon LS, Hedstrand DM. The role of branch cell symmetry and other critical nanoscale design parameters in the determination of dendrimer encapsulation properties. Biomolecules. 2020;10:642.
Kojima C, Regino C, Umeda Y, Kobayashi H, Kono K. Influence of dendrimer generation and polyethylene glycol length on the biodistribution of PEGylated dendrimers. Int J Pharm. 2010;383:293–6.
Tsujimoto A, Uehara H, Yoshida H, Nishio M, Furuta K, Inui T, et al. Different hydration states and passive tumor targeting ability of polyethylene glycol-modified dendrimers with high and low PEG density. Mater Sci Eng C. 2021;126:112159.
Derkaoui N, Said S, Grohens Y, Olier R, Privat M. PEG400 novel phase description in water. J Colloid Interface Sci. 2007;305:330–8.
Branca C, Magazù S, Maisano G, Migliardo F, Migliardo P, Romeo G. Hydration study of PEG/water mixtures by quasi elastic light scattering, acoustic and rheological measurements. J Phys Chem B. 2002;106:10272–6.
Begum R, Matsuura H. Conformational properties of short poly(oxyethylene) chains in water studied by IR spectroscopy. J Chem Soc Faraday Trans. 1997;93:3839–48.
Tajiri T, Morita S, Ozaki Y. Time-resolved conformational analysis of poly(ethylene oxide) during the hydrogelling process. Polymer. 2011;52:5560–6.
Hey MJ, Ilett SM. Poly(ethylene oxide) hydration studied by differential scanning calorimetry. J Chem Soc Faraday Trans. 1991;87:3671–5.
Hatakeyma T, Kasuga H, Tanaka M, Hatakeyama H. Cold crystallization of poly(ethylene glycol)-water systems. Thermochim Acta. 2007;465:59–66.
Huang L, Nishinari K. Interaction between poly(ethylene glycol) and water as studied by differential scanning calorimetry. J Polym Sci B. 2001;39:496–506.
Kuttich B, Matt A, Appel C, Stuhn B. X-ray scattering study on the crystalline and semi-crystalline structure of water/PEG mixtures in their eutectic phase diagram. Soft Matter. 2020;16:10260–7.
Gemmei-Ide M, Motonaga T, Kasai R, Kitano H. Two-step recrystallization of water in concentrated aqueous solution of poly(ethylene glycol). J Phys Chem B. 2013;117:2188–94.
Gemmei-Ide M, Miyashita T, Kagaya S, Kitano H. Mid-infrared spectroscopic investigation of the perfect vitrification of poly(ethylene glycol) aqueous solutions. Langmuir. 2015;31:10881–7.
Fortes AD, Wood IG, Grigoriev D, Alfredsson M, Kipfstuhl S, Knight KS, et al. No evidence for large-scale proton ordering in Antarctic ice from powder neutron diffraction. J Chem Phys. 2004;120:11376–9.
Takahashi Y, Tadokoro H. Structural studies of polyethers, (-(CH2)m-O-)n. X. crystal structure of poly(ethylene oxide). Macromolecules. 1973;6:672–5.
Dormidontova EE. Influence of end groups on phase behavior and properties of PEO in aqueous solutions. Macromolecules. 2004;37:7747–61.
Barbey R, Lavanant L, Paripovic D, Schüwer N, Sugnaux C, Tugulu S, et al. Polymer brushes via surface-initiated controlled radical polymerization: Synthesis, characterization, properties, and applications. Chem Rev. 2009;109:5437–527.
We would like to thank Ms. Maya Okada and Mr. Junjie Yao (Osaka Prefecture University) for their help with figure and sample preparation, respectively. This work was supported by JSPS KAKENHI Grant Numbers JP19H05720, JP19H05717, and JP20H05232 (Grant-in-Aid for Scientific Research on Innovative Area: Aquatic Functional Materials). The XRD and FT-IR experiments were performed at BL40B2 and BL43IR of SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) (Proposal Nos. 2021A1069, 2021B1366, and 2022A1202), respectively. YS acknowledges experimental support from Dr. Noboru Ohta and Dr. Hiroshi Sekiguchi at SPring-8. We would like to thank Editage (www.editage.com) for English language editing.
Conflict of interest
The authors declare no competing interests.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Cite this article
Kojima, C., Suzuki, Y., Ikemoto, Y. et al. Comparative study of PEG and PEGylated dendrimers in their eutectic mixtures with water analyzed using X-ray diffraction and infrared spectroscopy. Polym J 55, 63–73 (2023). https://doi.org/10.1038/s41428-022-00700-5