On the formation of dendrimer/nucleolipids surface films for directed self-assembly

Abstract

We describe the formation and structure of nucleolipid/dendrimer multilayer films controlled by non-covalent interactions to obtain biomaterials that exhibit molecular recognition of nucleic acids. Layers of cationic poly(amidoamine) (PAMAM) dendrimers of generation 4 and the anionic nucleolipids 1,2-dilauroyl-sn-glycero-3-phosphatidylnucleosides (DLPNs) based on uridine (DLPU) and adenosine (DLPA) were first formed at the silica-water interface. The PAMAM/DLPN layers were then exposed to short oligonucleotides, polynucleotides and single stranded DNA (ssDNA). The interfacial properties were characterized using quartz crystal microbalance with dissipation monitoring, attenuated total reflection Fourier transform infrared spectroscopy and neutron reflectometry. Both types of DLPN were found to adsorb as aggregates to preadsorbed PAMAM monolayers with a similar interfacial structure and composition before rinsing with pure aqueous solution. Nucleic acids were found to interact with PAMAM/DLPA layers due to base pairing interactions, while the PAMAM/DLPU layers did not have the same capability. This was attributed to the structure of the DLPA layer, which is formed by aggregates that extend from the interface towards the bulk after rinsing with pure solvent, while the DLPU layer forms compact structures. In complementary experiments using a different protocol, premixed PAMAM/DLPN samples adsorbed to hydrophilic silica only when the mixtures contained positively charged aggregates, which is rationalized in terms of electrostatic forces. The PAMAM/DLPA layers formed from the adsorption of these mixtures also bind ssDNA although in this case the adsorption is mediated by the opposite charges of the film and the nucleic acid rather than specific base pairing. The observed molecular recognition of nucleic acids by dendrimers functionalized via non-covalent interactions with nucleolipids is discussed in terms of biomedical applications such as gene vectors and biosensors.

Liquid crystalline bacterial outer membranes are critical for antibiotic susceptibility

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The effect of the protein corona on the interaction between nanoparticles and lipid bilayers

“…We present here a study performed with QCM-D, 6,[34][35][36][37][38][39] combined with NR 37,[40][41][42][43] aimed at exploring the effect of soft and hard protein coronas on the interaction of polystyrene (PS) NPs with supported lipid bilayers.…”

Lipid and Nucleic Acid Chemistries: Combining the Best of Both Worlds to Construct Advanced Biomaterials

“…More recently, Berti and co‐workers reported the ability of NL bilayers to selectively bind single‐stranded nucleic acids . In another study, the binding between nucleotide lipid/dendrimer surfaces and oligonucleotides was reported . This system featured cationic poly(amidoamine) or PAMAM dendrimers ( Figure A), which formed films with negatively charged nucleotide lipids.…”

“…C) Sequential addition of dendrimers, DLPN, and nucleic acids allowing selective binding between the functionalized surface and nucleic acids. Reproduced with permission . Copyright 2015, Royal Society of Chemistry.…”