7 research outputs found
Enzyme Responsive Hyaluronic Acid Nanocapsules Containing Polyhexanide and Their Exposure to Bacteria To Prevent Infection
Antibacterial nanodevices could bring
coatings of plastic materials
and wound dressings a big step forward if the release of the antibacterial
agents could be triggered by the presence of the bacteria themselves.
Here, we show that novel hyaluronic acid (HA)-based nanocapsules containing
the antimicrobial agent polyhexanide are specifically cleaved in the
presence of hyaluronidase, a factor of pathogenicity and invasion
for bacteria like <i>Staphylococcus aureus</i> and <i>Escherichia coli</i>. This resulted in an efficient killing
of the pathogenic bacteria by the antimicrobial agent. The formation
of different polymeric nanocapsules was achieved through a polyaddition
reaction in inverse miniemulsion. After the synthesis, the nanocapsules
were transferred to an aqueous medium and investigated in terms of
size, size distribution, functionality, and morphology using dynamic
light scattering, zeta potential measurements and scanning electron
microscopy. The enzyme triggered release of a model dye and the antimicrobial
polyhexanide was monitored using fluorescence and UV spectroscopy.
The stability of the nanocapsules in several biological media was
tested and the interaction of nanocapsules with human serum protein
was studied using isothermal titration calorimetry. The antibacterial
effectiveness is demonstrated by determination of the antibacterial
activity and determination of the minimal bactericidal concentration
(MBC)
Suppressing Unspecific Cell Uptake for Targeted Delivery Using Hydroxyethyl Starch Nanocapsules
Synthesizing nanocarriers with stealth properties and
delivering a “payload” to the particular organ remains
a big challenge but is the prime prerequisite for any in vivo application.
As a nontoxic alternative to the modification by poly(ethylene glycol)
PEG, we describe the synthesis of cross-linked hydroxyethyl starch
(HES, <i>M</i><sub>w</sub> 200,000 g/mol) nanocapsules with
a size range of 170–300 nm, which do not show nonspecific uptake
into cells. The specific uptake was shown by coupling a folic acid
conjugate as a model targeting agent onto the surface of the nanocapsules,
because folic acid has a high affinity to a variety of human carcinoma
cell lines which overexpress the folate receptor on the cell surface.
The covalent binding of the folic acid conjugate onto HES capsules
was confirmed by FTIR and NMR spectroscopy. The coupling efficiency
was determined using fluorescence spectroscopy. The specific cellular
uptake of the HES nanocapsules after folic acid coupling into the
folate-receptor presenting cells was studied by confocal laser scanning
microscopy (CLSM) and flow cytometry
Glutathione Responsive Hyaluronic Acid Nanocapsules Obtained by Bioorthogonal Interfacial “Click” Reaction
Azide-functionalized hyaluronic acid
and disulfide dialkyne have
been used for “click” reaction polymerization at the
miniemulsion droplets interface leading to glutathione responsive
nanocapsules (NCs). Inverse miniemulsion polymerization was chosen,
due to its excellent performance properties, for example, tuning of
size and size distribution, shell thickness/density, and high pay
loading efficiency. The obtained size, size distribution, and encapsulation
efficiency were checked via fluorescent spectroscopy, and the tripeptide
glutathione was used to release an encapsulated fluorescent dye after
cleavage of the nanocapsules shell. To show the glutathione-mediated
intracellular cleavage of disulfide-containing NC shells, CellTracker
was encapsulated into the nanocapsules. The cellular uptake in dendritic
cells and the cleavage of the nanocapsules in the cells were studied
using confocal laser scanning microscopy. Because of the mild reaction
conditions used during the interfacial polymerization and the excellent
cleavage properties, we believe that the synthesis of glutathione
responsive hyaluronic acid NCs reported herein are of high interest
for the encapsulation and release of sensitive compounds at high yields
Interleukin‑2 Functionalized Nanocapsules for T Cell-Based Immunotherapy
A major
demand on immunotherapy is the direct interference with
specific immune cells <i>in vivo</i>. In contrast to antibody-engineered
nanoparticles to control dendritic cells function, targeting of T
cells for biomedical applications still remains an obstacle as they
disclose reduced endocytic activities. Here, by coupling the cytokine
interleukin-2 (IL-2) to the surface of hydroxyethyl starch nanocapsules,
we demonstrated a direct and specifc T cell targeting <i>in vitro</i> and <i>in vivo</i> by IL-2 receptor-mediated internalization.
For this purpose, defined amounts of azide-functionalized IL-2 were
linked to alkyne-functionalized hydroxyethyl starch nanocapsules <i>via</i> copper-free click reactions. In combination with validated
quantification of the surface-linked IL-2 with anthracen azide, this
method allowed for engineering IL-2-functionalized nanocapsules for
an efficient targeting of human and murine T cell populations with
various IL-2 receptor affinities. This nanocapsule-mediated technique
is a promising strategy for T cell-based immunotherapies and may be
translated to other cytokine-related targeting systems
Protein Corona of Nanoparticles: Distinct Proteins Regulate the Cellular Uptake
Understanding nanoparticle–protein
interactions is a crucial
issue in the development of targeted nanomaterial delivery. Besides
unraveling the composition of the nanoparticle’s protein coronas,
distinct proteins thereof could control nanoparticle uptake into specific
cell types. Here we differentially analyzed the protein corona composition
on four polymeric differently functionalized nanoparticles by label-free
quantitative mass spectrometry. Next, we correlated the relative abundance
of identified proteins in the corona with enhanced or decreased cellular
uptake of nanoparticles into human cancer and bone marrow stem cells
to identify key candidates. Finally, we verified these candidate proteins
by artificially decorating nanoparticles with individual proteins
showing that nanoparticles precoated with the apolipoproteins ApoA4
or ApoC3 significantly decreased the cellular uptake, whereas precoating
with ApoH increased the cellular uptake
Protein Corona of Nanoparticles: Distinct Proteins Regulate the Cellular Uptake
Understanding nanoparticle–protein
interactions is a crucial
issue in the development of targeted nanomaterial delivery. Besides
unraveling the composition of the nanoparticle’s protein coronas,
distinct proteins thereof could control nanoparticle uptake into specific
cell types. Here we differentially analyzed the protein corona composition
on four polymeric differently functionalized nanoparticles by label-free
quantitative mass spectrometry. Next, we correlated the relative abundance
of identified proteins in the corona with enhanced or decreased cellular
uptake of nanoparticles into human cancer and bone marrow stem cells
to identify key candidates. Finally, we verified these candidate proteins
by artificially decorating nanoparticles with individual proteins
showing that nanoparticles precoated with the apolipoproteins ApoA4
or ApoC3 significantly decreased the cellular uptake, whereas precoating
with ApoH increased the cellular uptake
Enhanced in Vivo Targeting of Murine Nonparenchymal Liver Cells with Monophosphoryl Lipid A Functionalized Microcapsules
A broad spectrum of infectious liver
diseases emphasizes the need
of microparticles for targeted delivery of immunomodulatory substances
to the liver. Microcapsules (MCs) are particularly attractive for
innovative drug and vaccine formulations, enabling the combination
of antigen, drugs, and adjuvants. The present study aimed to develop
microcapsules characterized by an enhanced liver deposition and accelerated
uptake by nonparenchymal liver cells (NPCs). Initially, two formulations
of biodegradable microcapsules were synthesized from either hydroxyethyl
starch (HES) or mannose. Notably, HES-MCs accumulated primarily in
the liver, while mannose particles displayed a lung preference. Functionalization
of HES-MCs with anti-CD40, anti-DEC205, and/or monophosphoryl lipid
A (MPLA) enhanced uptake of MCs by nonparenchymal liver cells in vitro.
In contrast, only MPLA-coated HES-MCs promoted significantly the in
vivo uptake by NPCs. Finally, HES-MCs equipped with MPLA, anti-CD40,
and anti-DEC205 induced the secretion of TNF-α, IL-6 by Kupffer
cells (KCs), and IFN-γ and IL-12p70 by liver dendritic cells
(DCs). The enhanced uptake and activation of KCs by MPLA-HES-MCs is
a promising approach to prevent or treat infection, since KCs are
exploited as an entry gate in various infectious diseases, such as
malaria. In parallel, loading and activating liver DCs, usually prone
to tolerance, bears the potential to induce antigen specific, intrahepatic
immune responses necessary to prevent and treat infections affecting
the liver