Contribution of Temperature to Deformation of Adsorbed Vesicles Studied by Nanoplasmonic Biosensing

Abstract

With increasing temperature, biological macromolecules and nanometer-sized aggregates typically undergo complex and poorly understood reconfigurations, especially in the adsorbed state. Herein, we demonstrate the strong potential of using localized surface plasmon resonance (LSPR) sensors to address challenging questions related to this topic. By employing an LSPR-based gold nanodisk array platform, we have studied the adsorption of sub-100-nm diameter 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) lipid vesicles on titanium oxide at two temperatures, 23 and 50 °C. Inside this temperature range, DPPC lipid vesicles undergo the gel-to-fluid phase transition accompanied by membrane area expansion, while DOPC lipid vesicles remain in the fluid-phase state. To interpret the corresponding measurement results, we have derived general equations describing the effect of deformation of adsorbed vesicles on the LSPR signal. At the two temperatures, the shape of adsorbed DPPC lipid vesicles on titanium oxide remains nearly equivalent, while DOPC lipid vesicles become less deformed at higher temperature. Adsorption and rupture of DPPC lipid vesicles on silicon oxide were also studied for comparison. In contrast to the results obtained on titanium oxide, adsorbed vesicles on silicon oxide become more deformed at higher temperature. Collectively, the findings demonstrate that increasing temperature may ultimately promote, hinder, or have negligible effect on the deformation of adsorbed vesicles. The physics behind these observations is discussed, and helps to clarify the interplay of various, often hidden, factors involved in adsorption of biological macromolecules at interfaces.

Hydrodynamic Propulsion of Liposomes Electrostatically Attracted to a Lipid Membrane Reveals Size-Dependent Conformational Changes

“…39 The above mentioned studies demonstrate the potential of combined diffusivity and drift velocity measurements to extract properties of particles that are confined to a mobile interface, but did not specifically address that liposomes may deform in response to interfacial interactions, as previously observed at solid interfaces. [40][41][42][43][44][45][46] Inspired by the design of lipid nanoparticles that has been proven efficient in various drug delivery applications, we here apply this approach to determine both the size and conformational changes of individual membrane-adhering liposomes induced by direct membrane-membrane interactions controlled by electrostatic attraction between oppositely charged lipid bilayers in close contact. 47,48 The observed dependence of liposome deformation on size and membrane rigidity is discussed in the context of understanding how to optimize lipid nanoparticle formulations.…”

Fabrication of Au nanoparticles on poly(vinylpyrrolidone) nanowires exhibiting reversible frequency change of localized surface plasmon resonance

“…In particular, LSPR sensors have been extensively investigated in terms of changes in peak shift or extinction in response to refractive index changes in different media. [9][10][11] Of the various parameters that affect the LSPR frequency, the interparticle distance is particularly interesting; it controls the coupling of the plasmonic bands between adjacent NPs. The near-fields on one particle can interact with those on adjacent particles resulting in coupled plasmon oscillations.…”

Construction of Plasmonic Nano‐Biosensor‐Based Devices for Point‐of‐Care Testing

“…In the meanwhile, high specificity and strong anti‐interference are challenges for LSPR biosensing to achieve the detection of real samples. Nowadays, LSPR‐based biochemical detections include the detection of targets ranging from ions, small molecules in vapors and solutions to biomolecules such as nucleic acids, proteins, and even lipid vesicles, pathogens, and cells . LSPR sensing is based on nanometer‐sized structures and can be performed in simple transmission and reflection modes, which have potential to get rid of bulky auxiliary system and integrate LSPR sensor into miniaturized devices .…”