Thermoresponsive Polymers for Nuclear Medicine: Which Polymer Is the Best?

Ondrej Sedlacek, Peter Cernoch, Jan Kucka, Rafa Konefal, Petr Stepanek, Miroslav Vetrik, Timothy P. Lodge, Martin Hruby

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


Thermoresponsive polymers showing cloud point temperatures (CPT) in aqueous solutions are very promising for the construction of various systems in biomedical field. In many of these applications these polymers get in contact with ionizing radiation, e.g., if they are used as carriers for radiopharmaceuticals or during radiation sterilization. Despite this fact, radiosensitivity of these polymers is largely overlooked to date. In this work, we describe the effect of electron beam ionizing radiation on the physicochemical and phase separation properties of selected thermoresponsive polymers with CPT between room and body temperature. Stability of the polymers to radiation (doses 0-20 kGy) in aqueous solutions increased in the order poly(N-vinylcaprolactam) (PVCL, the least stable) ? poly[N-(2,2-difluoroethyl)acrylamide] (DFP) < poly(N-isopropylacrylamide) (PNIPAM) ? poly(2-isopropyl-2-oxazoline-co-2-n-butyl-2-oxazoline) (POX). Even low doses of β radiation (1 kGy), which are highly relevant to the storage of polymer radiotherapeutics and sterilization of biomedical systems, cause significant increase in molecular weight due to cross-linking (except for POX, where this effect is weak). In the case of PVCL irradiated with low doses, the increase in molecular weight induced an increase in the CPT of the polymer. For PNIPAM and DFP, there is strong chain hydrophilization leading to an increase in CPT. From this perspective, POX is the most suitable polymer for the construction of delivery systems that experience exposure to radiation, while PVCL is the least suitable and PNIPAM and DFP are suitable only for low radiation demands.

Original languageEnglish (US)
Pages (from-to)6115-6122
Number of pages8
Issue number24
StatePublished - Jun 21 2016

Bibliographical note

Funding Information:
The authors acknowledge the financial support from Ministry of Education, Youth and Sports of the Czech Republic (grant # KONTAKT LH14079), Czech Grant Foundation (grant # 16-03156S), and Ministry of Health of the Czech Republic (grant # 15-25781a). Partial support from the National Science Foundation through the University of Minnesota MRSEC (DMR-1420013) is also acknowledged (T.P.L.).

How much support was provided by MRSEC?

  • Partial

Reporting period for MRSEC

  • Period 3

PubMed: MeSH publication types

  • Journal Article

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