| 1. |
- Jõemetsa, Silver, 1990, et al.
(författare)
-
Independent Size and Fluorescence Emission Determination of Individual Biological Nanoparticles Reveals that Lipophilic Dye Incorporation Does Not Scale with Particle Size
- 2020
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 1520-5827 .- 0743-7463. ; 36:33, s. 9693-9700
-
Tidskriftsartikel (refereegranskat)abstract
- Advancements in nanoparticle characterization techniques are critical for improving the understanding of how biological nanoparticles (BNPs) contribute to different cellular processes, such as cellular communication, viral infection, as well as various drug-delivery applications. Since BNPs are intrinsically heterogeneous, there is a need for characterization methods that are capable of providing information about multiple parameters simultaneously, preferably at the single-nanoparticle level. In this work, fluorescence microscopy was combined with surface-based two-dimensional flow nanometry, allowing for simultaneous and independent determination of size and fluorescence emission of individual BNPs. In this way, the dependence of the fluorescence emission of the commonly used self-inserting lipophilic dye 3,3′-dioctadecyl-5,5′-di(4-sulfophenyl)oxacarbocyanine (SP-DiO) could successfully be correlated with nanoparticle size for different types of BNPs, including synthetic lipid vesicles, lipid vesicles derived from cellular membrane extracts, and extracellular vesicles derived from human SH-SY5Y cell cultures; all vesicles had a radius, r, of ∼50 nm and similar size distributions. The results demonstrate that the dependence of fluorescence emission of SP-DiO on nanoparticle size varies significantly between the different types of BNPs, with the expected dependence on membrane area, r2, being observed for synthetic lipid vesicles, while a significant weaker dependence on size was observed for BNPs with more complex composition. The latter observation is attributed to a size-dependent difference in membrane composition, which may influence either the optical properties of the dye and/or the insertion efficiency, indicating that the fluorescence emission of this type of self-inserting dye may not be reliable for determining size or size distribution of BNPs with complex lipid compositions.
|
|
| 2. |
- Hossain, Shakhawath, et al.
(författare)
-
Influence of Bile Composition on Membrane Incorporation of Transient Permeability Enhancers
- 2020
-
Ingår i: Molecular Pharmaceutics. - : American Chemical Society (ACS). - 1543-8392 .- 1543-8384. ; 17:11, s. 4226-4240
-
Tidskriftsartikel (refereegranskat)abstract
- Transient permeability enhancers (PEs), such as caprylate, caprate, and salcaprozate sodium (SNAC), improve the bioavailability of poorly permeable macromolecular drugs. However, the effects are variable across individuals and classes of macromolecular drugs and biologics. Here, we examined the influence of bile compositions on the ability of membrane incorporation of three transient PEs-caprylate, caprate, and SNAC-using coarse-grained molecular dynamics (CG-MD). The availability of free PE monomers, which are important near the absorption site, to become incorporated into the membrane was higher in fasted-state fluids than that in fed-state fluids. The simulations also showed that transmembrane perturbation, i.e., insertion of PEs into the membrane, is a key mechanism by which caprylate and caprate increase permeability. In contrast, SNAC was mainly adsorbed onto the membrane surface, indicating a different mode of action. Membrane incorporation of caprylate and caprate was also influenced by bile composition, with more incorporation into fasted- than fed-state fluids. The simulations of transient PE interaction with membranes were further evaluated using two experimental techniques: the quartz crystal microbalance with dissipation technique and total internal reflection fluorescence microscopy. The experimental results were in good agreement with the computational simulations. Finally, the kinetics of membrane insertion was studied with CG-MD. Variation in micelle composition affected the insertion rates of caprate monomer insertion and expulsion from the micelle surface. In conclusion, this study suggests that the bile composition and the luminal composition of the intestinal fluid are important factors contributing to the interindividual variability in the absorption of macromolecular drugs administered with transient PEs.
|
|
| 3. |
- Joyce, Paul, 1989, et al.
(författare)
-
Enhancing the cellular uptake and antibacterial activity of rifampicin through encapsulation in mesoporous silica nanoparticles
- 2020
-
Ingår i: Nanomaterials. - : MDPI AG. - 2079-4991. ; 10:4
-
Tidskriftsartikel (refereegranskat)abstract
- An urgent demand exists for the development of novel delivery systems that efficiently transport antibacterial agents across cellular membranes for the eradication of intracellular pathogens. In this study, the clinically relevant poorly water-soluble antibiotic, rifampicin, was confined within mesoporous silica nanoparticles (MSN) to investigate their ability to serve as an efficacious nanocarrier system against small colony variants of Staphylococcus aureus (SCV S. aureus) hosted within Caco-2 cells. The surface chemistry and particle size of MSN were varied through modifications during synthesis, where 40 nm particles with high silanol group densities promoted enhanced cellular uptake. Extensive biophysical analysis was performed, using quartz crystal microbalance with dissipation (QCM-D) and total internal reflection fluorescence (TIRF) microscopy, to elucidate the mechanism of MSN adsorption onto semi-native supported lipid bilayers (snSLB) and, thus, uncover potential cellular uptake mechanisms of MSN into Caco-2 cells. Such studies revealed that MSN with reduced silanol group densities were prone to greater particle aggregation on snSLB, which was expected to restrict endocytosis. MSN adsorption and uptake into Caco-2 cells correlated well with antibacterial efficacy against SCV S. aureus, with 40 nm hydrophilic particles triggering a ~2.5-log greater reduction in colony forming units, compared to the pure rifampicin. Thus, this study provides evidence for the potential to design silica nanocarrier systems with controlled surface chemistries that can be used to re-sensitise intracellular bacteria to antibiotics by delivering them to the site of infection.
|
|
| 4. |
- Joyce, Paul, 1989, et al.
(författare)
-
Polymer lipid hybrid (PLH) formulations: A synergistic approach to oral delivery of challenging therapeutics. A synergistic approach to oral delivery of challenging therapeutics
- 2020
-
Ingår i: Delivery of Drugs: Volume 2: Expectations and Realities of Multifunctional Drug Delivery Systems. ; , s. 1-27
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- In recent decades, lipid-based formulations and polymeric systems have emerged concurrently as the predominant approaches for overcoming low gastrointestinal stability/solubility and rate-limiting dissolution drawbacks that are associated with a wide range of therapeutics, including lipophilic small molecules and sensitive macromolecules. While these conventional approaches have demonstrated the ability to overcome drug absorption barriers and subsequently improve oral biopharmaceutical performance, a number of fundamental limitations have restricted the translation of promising preclinical and clinical findings into commercial success. Furthermore, the increasing complexity of novel therapeutics has amplified the demand for innovative and intelligent carrier systems that effectively transport drug molecules to the primary site of absorption. Consequently, recent focus has been attributed to designing and engineering polymer-lipid hybrid (PLH) formulations that combine the solubilization capacity of lipids with the stabilizing matrix of polymeric systems. This presents a synergistic approach to oral drug delivery with proven potential for overcoming limitations associated with the precursor systems. This chapter focuses specifically on the development of PLH systems, with emphasis placed on the relationship between nanostructure/surface chemistry and the physicochemical and biopharmaceutical performance of the hybrid formulation.
|
|
