Nanoparticle Middlemen Trigger Drug Release | Chemical & Engineering News
Volume 90 Issue 41 | p. 43 | Concentrates
Issue Date: October 8, 2012

Nanoparticle Middlemen Trigger Drug Release

Gel embedded with lanthanide nanoparticles releases embedded protein drugs when particles absorb near-infrared light
Department: Science & Technology
News Channels: Nano SCENE, Materials SCENE, Biological SCENE
Keywords: photosensitive hydrogels, lanthanide nanoparticles, upconversion, near infrared light
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Near-infrared light (red) penetrates a photosensitive hydrogel, hitting lanthanide nanoparticles (green circles) that then release ultraviolet light (purple). These photons trigger photoresponsive chemical groups in the polymer backbones (red triangles) to cleave the polymer chains (black curves) and release proteins (yellow).
Credit: J. Am. Chem. Soc.
Schematic of hydrogel containing upconversion lanthanide nanoparticles. The gels could release protein drugs on cue when hit with near-infrared light.
 
Near-infrared light (red) penetrates a photosensitive hydrogel, hitting lanthanide nanoparticles (green circles) that then release ultraviolet light (purple). These photons trigger photoresponsive chemical groups in the polymer backbones (red triangles) to cleave the polymer chains (black curves) and release proteins (yellow).
Credit: J. Am. Chem. Soc.

A hydrogel containing lanthanide-based nanoparticles releases proteins inside the gel when hit with near-infrared light (J. Am. Chem. Soc., DOI: 10.1021/ja308876j). The nanoparticle-studded gel could enable doctors to cue the release of protein drugs deep inside a patient’s tissues, the developers say. Yue Zhao of the University of Sherbrooke, in Quebec, and Neil R. Branda of Simon Fraser University, in British Columbia, wanted to make hydrogels responsive to near-IR light, which is safer and can penetrate deeper into tissue than ultraviolet light. They impregnated a hydrogel with nanoparticles composed of a NaYF4 core doped with thulium and ytterbium and wrapped with a NaYF4 shell. The hydrogel is a cross-linked web of polyacrylamide and polyethylene glycol, held together by photoresponsive o-nitrobenzyl groups. When exposed to near-IR light, the nanoparticles emit UV light through a process called upconversion. The UV light then triggers the nitrobenzyl groups to cleave the polymer chains. The team tested their gel by filling it with a fluorescently labeled protein. After about 50 minutes of irradiation with near-IR light, almost 70% of the protein escaped from the gel.

 
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