5 research outputs found
Biodegradable Nanoneedles for Localized Delivery of Nanoparticles <i>in Vivo:</i> Exploring the Biointerface
Nanoneedles display potential in mediating the delivery of drugs and biologicals, as well as intracellular sensing and single-cell stimulation, through direct access to the cell cytoplasm. Nanoneedles enable cytosolic delivery, negotiating the cell membrane and the endolysosomal system, thus overcoming these major obstacles to the efficacy of nanotherapeutics. The low toxicity and minimal invasiveness of nanoneedles have a potential for the sustained nonimmunogenic delivery of payloads <i>in vivo,</i> provided that the development of biocompatible nanoneedles with a simple deployment strategy is achieved. Here we present a mesoporous silicon nanoneedle array that achieves a tight interface with the cell, rapidly negotiating local biological barriers to grant temporary access to the cytosol with minimal impact on cell viability. The tightness of this interfacing enables both delivery of cell-impermeant quantum dots <i>in vivo</i> and live intracellular sensing of pH. Dissecting the biointerface over time elucidated the dynamics of cell association and nanoneedle biodegradation, showing rapid interfacing leading to cytosolic payload delivery within less than 30 minutes <i>in vitro</i>. The rapid and simple application of nanoneedles <i>in vivo</i> to the surface of tissues with different architectures invariably resulted in the localized delivery of quantum dots to the superficial cells and their prolonged retention. This investigation provides an understanding of the dynamics of nanoneedles’ biointerface and delivery, outlining a strategy for highly local intracellular delivery of nanoparticles and cell-impermeant payloads within live tissues
PLGA-Mesoporous Silicon Microspheres for the <i>in Vivo</i> Controlled Temporospatial Delivery of Proteins
In regenerative medicine, the temporospatially
controlled delivery
of growth factors (GFs) is crucial to trigger the desired healing
mechanisms in the target tissues. The uncontrolled release of GFs
has been demonstrated to cause severe side effects in the surrounding
tissues. The aim of this study was to optimize a translational approach
for the fine temporal and spatial control over the release of proteins, <i>in vivo</i>. Hence, we proposed a newly developed multiscale
composite microsphere based on a core consisting of the nanostructured
silicon multistage vector (MSV) and a polyÂ(dl-lactide-<i>co</i>-glycolide) acid (PLGA) outer shell. Both of the two components
of the resulting composite microspheres (PLGA-MSV) can be independently
tailored to achieve multiple release kinetics contributing to the
control of the release profile of a reporter protein <i>in vitro</i>. The influence of MSV shape (hemispherical or discoidal) and size
(1, 3, or 7 μm) on PLGA-MSV’s morphology and size distribution
was investigated. Second, the copolymer ratio of the PLGA used to
fabricate the outer shell of PLGA-MSV was varied. The composites were
fully characterized by optical microscopy, scanning electron microscopy,
ζ potential, Fourier transform infrared spectroscopy, and thermogravimetric
analysis–differential scanning calorimetry, and their release
kinetics over 30 days. PLGA-MSV’s biocompatibility was assessed <i>in vitro</i> with J774 macrophages. Finally, the formulation
of PLGA-MSV was selected, which concurrently provided the most consistent
microsphere size and allowed for a zero-order release kinetic. The
selected PLGA-MSVs were injected in a subcutaneous model in mice,
and the <i>in vivo</i> release of the reporter protein was
followed over 2 weeks by intravital microscopy, to assess if the zero-order
release was preserved. PLGA-MSV was able to retain the payload over
2 weeks, avoiding the initial burst release typical of most drug delivery
systems. Finally, histological evaluation assessed the biocompatibility
of the platform <i>in vivo</i>
Enhancing Vascularization through the Controlled Release of Platelet-Derived Growth Factor-BB
Using
delivery systems to control the in vivo release of growth factors
(GFs) for tissue engineering applications is extremely desirable as
the clinical use of GFs is limited by their fast in vivo turnover.
Hence, the development of effective platforms that are able to finely
control the release of GFs in vivo remains a challenge. Herein, we investigated
the ability of multiscale microspheres, composed by a nanostructured
silicon multistage vector (MSV) core and a polyÂ(dl-lactide-<i>co</i>-glycolide) acid (PLGA) forming outer shell (PLGA-MSV),
to release functional platelet-derived growth factor-BB (PDGF-BB)
to induce in vivo localized neovascularization. The in vitro release
of PDGF-BB was assessed by enzyme-linked immunosorbent assay (ELISA)
over 2 weeks and showed a sustained, zero-order release kinetics.
The ability to promote in vivo localized neovascularization was investigated
in a subcutaneous injection model in BALB/c mice and followed by intravital
microscopy up to 2 weeks. Fully functional newly formed vessels were
found within the area where PLGA-MSVs were localized and covered 3.0 ±
0.9 and 19 ± 5.1% at 7 and 14 days, respectively, showing a 6-fold
increase in 1 week. The distribution of CD31<sup>+</sup> and α-SMA<sup>+</sup> cells was detected by immunofluorescence on harvested tissues.
CD31 was significantly more expressed (4-fold increase) compared to
the untreated control. Finally, the level of up-regulation of angiogenesis-associated
genes (Vegfa, Vwf, and Col3a1) was assessed by q-PCR, resulting in
a significantly higher expression where PLGA-MSVs were localized (Vegfa:
2.32 ± 0.50 at 7 days and 4.37 ± 0.75 at 14 days; Vwf: 4.13
± 0.82 and 7.74 ± 0.91; Col3a1: 5.43 ± 0.37 and 6.66
± 0.89). Altogether, our data supported the conclusion that the
localized delivery of PDGF-BB from PLGA-MSVs induced the localized
de novo formation of fully functional vessels in vivo. With this study,
we demonstrated that PLGA-MSV holds promise for accomplishing the
controlled localized in vivo release of GFs for the design of innovative
tissue engineering strategies
Unveiling the <i>in Vivo</i> Protein Corona of Circulating Leukocyte-like Carriers
Understanding
interactions occurring at the interface between nanoparticles
and biological components is an urgent challenge in nanomedicine due
to their effect on the biological fate of nanoparticles. After the
systemic injection of nanoparticles, a protein corona constructed
by blood components surrounds the carrier’s surface and modulates
its pharmacokinetics and biodistribution. Biomimicry-based approaches
in nanotechnology attempt to imitate what happens in nature in order
to transfer specific natural functionalities to synthetic nanoparticles.
Several biomimetic formulations have been developed, showing superior <i>in vivo</i> features as a result of their cell-like identity.
We have recently designed biomimetic liposomes, called leukosomes,
which recapitulate the ability of leukocytes to target inflamed endothelium
and escape clearance by the immune system. To gain insight into the
properties of leukosomes, we decided to investigate their protein
corona <i>in vivo</i>. So far, most information about the
protein corona has been obtained using <i>in vitro</i> experiments,
which have been shown to minimally reproduce <i>in vivo</i> phenomena. Here we directly show a time-dependent quantitative and
qualitative analysis of the protein corona adsorbed <i>in vivo</i> on leukosomes and control liposomes. We observed that leukosomes
absorb fewer proteins than liposomes, and we identified a group of
proteins specifically adsorbed on leukosomes. Moreover, we hypothesize
that the presence of macrophage receptors on leukosomes’ surface
neutralizes their protein corona-meditated uptake by immune cells.
This work unveils the protein corona of a biomimetic carrier and is
one of the few studies on the corona performed <i>in vivo</i>
Soft Discoidal Polymeric Nanoconstructs Resist Macrophage Uptake and Enhance Vascular Targeting in Tumors
Most nanoparticles for biomedical applications originate from the self-assembling of individual constituents through molecular interactions and possess limited geometry control and stability. Here, 1000 × 400 nm discoidal polymeric nanoconstructs (DPNs) are demonstrated by mixing hydrophobic and hydrophilic polymers with lipid chains and curing the resulting paste directly within silicon templates. By changing the paste composition, soft- and rigid-DPNs (s- and r-DPNs) are synthesized exhibiting the same geometry, a moderately negative surface electrostatic charge (−14 mV), and different mechanical stiffness (∼1.3 and 15 kPa, respectively). Upon injection in mice bearing nonorthotopic brain or skin cancers, s-DPNs exhibit ∼24 h circulation half-life and accumulate up to ∼20% of the injected dose per gram tumor, detecting malignant masses as small as ∼0.1% the animal weight <i>via</i> PET imaging. This unprecedented behavior is ascribed to the unique combination of geometry, surface properties, and mechanical stiffness which minimizes s-DPN sequestration by the mononuclear phagocyte system. Our results could boost the interest in using less conventional delivery systems for cancer theranosis