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Breaking isolation to form new networks: Ph-triggered changes in connectivity inside lipid nanoparticles

DOI: 10.1021/jacs.1c06244 DOI Help

Authors: Zexi Xu (University of Leeds) , John M. Seddon (Imperial College London) , Paul A. Beales (University of Leeds) , Michael Rappolt (University of Leeds) , Arwen I. I. Tyler (University of Leeds)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of The American Chemical Society

State: Published (Approved)
Published: September 2021
Diamond Proposal Number(s): 18027 , 22659 , 24530

Abstract: There is a growing demand to develop smart nanomaterials that are structure-responsive as they have the potential to offer enhanced dose, temporal and spatial control of compounds and chemical processes. The naturally occurring pH gradients found throughout the body make pH an attractive stimulus for guiding the response of a nanocarrier to specific locations or (sub)cellular compartments in the body. Here we have engineered highly sensitive lyotropic liquid crystalline nanoparticles that reversibly respond to changes in pH by altering the connectivity within their structure at physiological temperatures. At pH 7.4, the nanoparticles have an internal structure consisting of discontinuous inverse micellar “aqueous pockets” based on space group Fd3m. When the pH is ≤6, the nanoparticles change from a compartmentalized to an accessible porous internal structure based on a 2D inverse hexagonal phase (plane group p6mm). We validate the internal symmetry of the nanoparticles using small-angle X-ray scattering and cryogenic transmission electron microscopy. The high-resolution electron microscopy images obtained have allowed us for the first time to directly visualize the internal structure of the Fd3m nanoparticles and resolve the two different-sized inverse micelles that make up the structural motif within the Fd3m unit cell, which upon structural analysis reveal excellent agreement with theoretical geometrical models.

Journal Keywords: Nanoparticles; Lattices; Micelles; pH; Phase transitions

Subject Areas: Chemistry, Engineering

Instruments: I22-Small angle scattering & Diffraction

Added On: 04/10/2021 08:47

Discipline Tags:

Chemical Engineering Engineering & Technology Nanoscience/Nanotechnology Soft condensed matter physics Chemistry

Technical Tags:

Scattering Small Angle X-ray Scattering (SAXS)