Fluorescent Labeling of Hyaluronic Acid-Chitosan Nanocarriers by Protein-Stabilized Gold Nanoclusters

Abstract

In medical research the visualization of drug carrier accumulation and release of the loaded drugs in vivo is an important field. In this work, two protein-stabilized gold nanoclusters (Au NCs) as effective fluorescent reporters (FRs) were investigated for labeling of biocompatible chitosan-modified hyaluronic acid based nanocarriers having two different structures. The colloid stability of the labeled carriers was studied by dynamic light scattering and Zeta potential measurements, while the changes in the fluorescence of the lysozyme- (LYZ) and bovine serum albumin (BSA)-stabilized Au NCs were analyzed by spectrofluorimetry and confocal fluorescent microscopy. We found that the labeling was effective with a wide range of marker:carrier mass ratios, and the fluorescence of the NCs and the colloid stability of the complexes were retained. Labeling during preparation and subsequent labeling were compared, and based on composition (nanocluster:carrier mass ratio) and structure of the complex systems we preferred the latter method, as it left the Au NCs free for further modifications. Considering both marker:carrier mass ratios and emission intensities, the LYZ-stabilized Au NCs proved to be better labels. The core-shell type carrier formulations showed increased fluorescence with LYZ-stabilized NCs, presumably from aggregation induced emission.

Colloidal Polyelectrolyte Complexes from Hyaluronic Acid: Preparation and Biomedical Applications

“…Besides Zn(II), tripolyphosphate (TPP) can also be used as an adjuvant ion to stabilize HA/CTS PEC NPs in physiological salines. [ 31,33,42,61,129,149,150 ] The stabilizing effect of TPP stems from the crosslinking of CTS through electrostatic interactions between anionic charges of phosphate groups in TPP and amine groups in CTS. [ 151 ] The effects of glutamate as a counter‐anion on HA/CTS PECs have also been described.…”

Glutathione Disulfide as a Reducing, Capping, and Mass-Separating Agent for the Synthesis and Enrichment of Gold Nanoclusters

“…For sensitive detection, additional strategies are often employed, such as lanthanide ion-induced enhancement [ 12 ], two-photon excited photoluminescence [ 13 ], and even enrichment of the nanoclusters [ 14 ]. In fact, enrichment is an indispensable step in the applications where high-concentration nanoclusters are needed, e.g., catalysis [ 15 , 16 , 17 ], therapy [ 18 , 19 ], and electronic and optical industries [ 20 , 21 , 22 , 23 , 24 ]. A number of concentration methods can potentially be used for this purpose, for instance, ultracentrifugation, ultrafiltration, reduced-pressure evaporation, chromatography, centrifugation, nanofluidic system, organic solvent-induced precipitation, and liquid–liquid extraction [ 25 , 26 , 27 , 28 , 29 ].…”

Fluorescent Nanosystems for Drug Tracking and Theranostics: Recent Applications in the Ocular Field

“…Among the most investigated fluorescent nanosystems, there are lipid-based nanocarriers—such as nanostructured lipid carriers (NLCs) and solid lipid nanoparticles (SLNs), polymeric nanoparticles and nanocapsules, hybrid nanoparticles, cubosomes, emulsomes, nanoemulsions, niosomes, liposomes, films, nanomicelles and hydrogels. Fluorescence is introduced through the methods commonly used to prepare nanosystems [ 97 , 98 ]. The fluorescent nanosystems are essentially divided into (i) probe-loaded, in which the dye or probe is encapsulated into the system mostly during the formulation processes, and (ii) labeled/grafted, in which the probe is covalently bound to the surface of the nanosystem (often linked to some matrix component, such as polymers or lipids), always forming an adduct ( Figure 3 ).…”