Hierarchical Quatsome-RGD Nanoarchitectonic Surfaces for Enhanced Integrin-Mediated Cell Adhesion

Abstract

The synthesis and study of the tripeptide Arg-Gly-Asp (RGD), the binding site of different extracellular matrix proteins, e.g., fibronectin and vitronectin, has allowed the production of a wide range of cell adhesive surfaces. Although the surface density and spacing of the RGD peptide at the nanoscale have already shown a significant influence on cell adhesion, the impact of its hierarchical nanostructure is still rather unexplored. Accordingly, a versatile colloidal system named quatsomes, based on fluid nanovesicles formed by the self-assembling of cholesterol and surfactant molecules, has been devised as a novel template to achieve hierarchical nanostructures of the RGD peptide. To this end, RGD was anchored on the vesicle’s fluid membrane of quatsomes, and the RGD-functionalized nanovesicles were covalently anchored to planar gold surfaces, forming a state of quasi-suspension, through a long poly(ethylene glycol) (PEG) chain with a thiol termination. An underlying self-assembled monolayer (SAM) of a shorter PEG was introduced for vesicle stabilization and to avoid unspecific cell adhesion. In comparison with substrates featuring a homogeneous distribution of RGD peptides, the resulting hierarchical nanoarchitectonic dramatically enhanced cell adhesion, despite lower overall RGD molecules on the surface. The new versatile platform was thoroughly characterized using a multitechnique approach, proving its enhanced performance. These findings open new methods for the hierarchical immobilization of biomolecules on surfaces using quatsomes as a robust and novel tissue engineering strategy.

Peptide-based self-assembled monolayers (SAMs): what peptides can do for SAMs and vice versa

“…Major advances were seen in the fabrication of anisotropic surfaces displaying peptide-SAMs with spatiotemporal control enabling the conceptualisation of more complex biological studies, such as the fabrication of SAM-based platforms for the hierarchical presentation of bioactive peptides. 117 Current research in this applicational area is focused on the fabrication of dynamic surfaces, through supramolecular approaches 114 or activation with external stimuli (e.g. light, electrical potentials) that are cell-compatible and allow multiple cycles of activation, 110 as well as on the increasing sophistication of the SAMs platforms (e.g., automation, robotisation), interfaced with mass spectrometry analytics, 233 to support and advance high throughput screening (HTS) programs 112 in drug discovery and diagnostics.…”

“…Although the field of SAMs seemed dormant, this review is a testimony that the field has not been stagnated, but rather deviated from its beginnings. With the discovery of novel peptide sequences by combinatorial, high-throughput, and machine learning methods (e.g., AMPs), and the emergence of applications using renewed peptide functions (e.g., peptide-assisted genome editing), 308 as well as the need to provide hierarchical presentation of epitopes, 117 peptide-SAMs will continue to provide a reliable platform for in vitro screening of artificial protein mimics that offers great flexibility for chemical processability, surface imaging and integration of sensors for detection. In fact, this review was conceived with the idea of reinvigorating the research on peptide-SAMs by showcasing the numerous transformative contributions made in the field and discussing emerging directions.…”

Evaluation of Quatsome Morphology, Composition, and Stability for Pseudomonas aeruginosa Biofilm Eradication

“…Quaternary ammonium compounds (QACs) are extensively used in industrial and household settings for bacteria treatment. Some amphiphilic QACs are able to self-assemble into cationic vesicles with sterol molecules in a 1:1 molecular ratio, and these vesicles are commonly called “quatsomes” (QSs). − QSs self-assembled from myristalkonium chloride (MKC) and cholesterol, − cetyltrimethylammonium bromide (CTAB) and cholesterol, ,, and other QACs have been studied, , collectively proving their stable and unique cationic bimolecular vesicle structure. The cationic QAC molecules adsorb to the polyanions on the bacterial membrane surface and insert their hydrophobic tails into the lipid bilayer to disrupt the cell membrane, causing cell leakage and lysis .…”

Quatsomes Loaded with Squaraine Dye as an Effective Photosensitizer for Photodynamic Therapy

“…This kind of vesicle has been proven to be safe and non-toxic for biomedical applications and has remained stable for years [ 42 , 43 ]. The encapsulation of PSs into QS is an attractive approach since it offers not only a strategy to bring non-soluble squaraine dyes into an aqueous media but also a list of advantages for its in vivo application: (i) longer times in circulation and higher cellular uptake [ 44 , 45 ], (ii) improved therapeutic efficiency with a lower dye concentration since the photosensitizer is highly localized at the therapeutic side [ 42 , 46 ] and, (iii) QS allows a targeted delivery by the nanovesicle functionalization with targeting units [ 47 , 48 ].…”