AFM/TEM Complementary Structural Analysis of Surface-Functionalized Nanoparticles

Abstract

HighlightsShort collection of bullet points of the core article 1. Nanomedicine deserves interesting perspective for real application in medicine and surface modified nanocarriers represent the cutting-edge of nanomedicine.2. Aiming to the maximum translatability, surface-modified nanocarriers must be properly characterized, in terms of surface properties. Advanced microscopies (Atomic Force Microscopy andTransmission Electron Microscopy) help in better understanding of the chemico-physical features of nanocarriers 4. AFM and TEM give high resolution outcomes and should be chosen depending on specific the nature of surface-ligands 5. AFM allows to discriminate on the qualitative evaluation of ligands of different nature (QDs vs antibody) , without any additional treatment and without operating in a vacuum environment AbstractIn the field of nanomedicine, the characterization of functionalized drug delivery systems, introduced on market as efficacious and selective therapeutics, represents a pivotal aspect of great importance. In particular, the morphology of polymeric nanoparticles, the most studied nanocarriers, is frequently assessed by transmission electron microscopy (TEM). Despite of TEM high resolution and versatility, this technology is frequently hampered by both the complicated procedure for sample preparation and the operative condition of analysis. Considering the scanning probe microscopies, atomic force microscopy (AFM) represents an extraordinary tool for the detailed characterization of submicron-size structure as the surface functionalization at the atomic scale. In this paper we discussed the advantage and limits of these microscopies applied to the characterization of PLGA nanoparticles functionalized with three different kinds of ligands (carbohydrate ligand, an antibody and quantum dots crystals) intentionally designed, created and tailored with specific physico-chemical properties to meet the needs of specific applications (targeting or imaging). quantum dots (QD) to obtain double imaging/drug release (theranostic aim). If compared with the encapsulation process, the conjugation and the exposure of QD on NPs surface is preferred in order to avoid the QD release and to ensure the optimal imaging [12,13]. Graphical Abstract PEG-QDs Materials and Methods Preparation of nanoparticlesAll NPs analysed were obtained according to the nanoprecipitation procedure [14]. The functionalization can be inserted during NPs formulation by using polymer previously modified (Neu5Ac-PLGA502) or after the NPs formation by activating the functional groups onto NPs surfaces by "in situ" reaction and subsequent conjugation with ligands (Rituximab-PLGA503 NP and QD-PLGA503 NPs).Sialic acid derivative conjugated nanoparticles (Neu5Ac-PLGA502 NPs) : Initially, PLGA502H (50% lactic/50% glycolic acid ratio, inherent viscosity 0.20 dl/g, MW 4900; Boehringer-Ingelheim, Ingelheim am Rhein, Germany), selected as polymer on the basis of the yield of sugar conjugation, was conjugated with Neu5Ac (Sigma Aldrich), a sialic acid...

Pd-Based Hybrid Nanoparticles As Multimodal Theranostic Nanomedicine

“…In particular, the dark zones for the bare PdNP, likely due to the nanoparticle capping by the soft PVP polymer, disappear, hidden by a shell visible around the core nanoparticle for the Pd@CisPt. This finding points to the effective binding of cisplatin molecules to the NP’s surface …”