John Garner

Poly(lactide) from PolySciTech used in generating light-activated shape-changing microparticles

Blog Post created by John Garner on Apr 5, 2018

Shape memory microparticles.jpg

Shape memory is an effect in which polymer chains temporarily entangle holding the material in a set shape until the polymer is heated above a specific rubber-glass transition temperature at which point the polymer chains can move and the material naturally forms back into its original shape. Recently, researchers at Johns Hopkins University purchased PLA (PolyVivo AP004) from PolySciTech ( and used it to create a gold nanoparticle loaded microparticle which changes from elongated shapes into spherical shapes when heated gently by exposure to light. This research holds promise to create materials with tunable macrophage uptake for a variety of biomedical applications. Read more: Guo, Qiongyu, Corey J. Bishop, Randall A. Meyer, David R. Wilson, Lauren Olasov, Daphne E. Schlesinger, Patrick T. Mather, James B. Spicer, Jennifer H. Elisseeff, and Jordan J. Green. "Entanglement-Based Thermoplastic Shape Memory Polymeric Particles with Photothermal Actuation for Biomedical Applications." ACS Applied Materials & Interfaces (2018).


“Abstract: Triggering shape memory functionality under clinical hyperthermia temperatures could enable the control and actuation of shape memory systems in clinical practice. For this purpose, we developed light-inducible shape memory microparticles composed of a poly (D,L-lactic acid) (PDLLA) matrix encapsulating gold nanoparticles (Au@PDLLA hybrid microparticles). This shape memory polymeric system for the first time demonstrates the capability of maintaining an anisotropic shape at body temperature with triggered shape memory effect back to a spherical shape at a narrow temperature range above body temperature with a proper shape recovery speed (37 ˚C < T < 45 ˚C). We applied a modified film-stretching processing method with carefully controlled stretching temperature to enable shape memory and anisotropy in these micron-sized particles. Accordingly, we achieved purely entanglement-based shape memory response without chemical crosslinks in the miniaturized shape memory system. Furthermore, these shape memory microparticles exhibited light-induced spatiotemporal control of their shape recovery using a laser to trigger photothermal heating of doped gold nanoparticles. This shape memory system is composed of biocompatible components and exhibits spatiotemporal controllability of its properties, demonstrating potential for various biomedical applications, such as tuning macrophage phagocytosis as demonstrated in this study.”


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