Thermoresponsive poly(2-oxazoline)s: From fundamental aspects to sensors with memory function and drug delivery vehicles

Abstract: 

Poly(2-oxazoline) are a synthetic class of polyamides that have been studied in great detail since their discovery in 1966. [1] Their synthesis allows broad tuning of their properties, from hydrophilic to hydrophobic and fluorophilic. [2]

Within this lecture, I will present our work on thermoresponsive poly(2-oxazoline)s (PAOx) that started with the development of alternatives for poly(N-isopropyl-2-oxazoline).[3] It was found that the phase transition temperature of PAOx can be tuned over the entire range of temperatures accessible in water under ambient pressure, whereby the phase transition does not show significant hysteresis unlike PNIPAM. The second part of the lecture will address the use of PAOx copolymers with both ethyl and nonyl side chains, in which the latter enable host-guest interactions with α-cyclodextrins leading to temperature sensing solutions with memory functions as shown in the Figure below.[ 4] Furthermore, the development of PAOx-coated gold nanoparticles as sensors and logic gates will be discussed. [5] In the final part of the lecture, the development of thermoresponsive PAOx as injectable drug depots will be discussed. [6] These polymer-drug conjugates are soluble in PBS buffer at room temperature while they form an insoluble depot at 37 °C providing a slow release drug depot.