Cinzia Stigliano

Inflammation after spinal cord injury (SCI) is characterized by immune cell invasion and activation, combined with inflammatory mediator release that worsens outcomes following primary trauma. Effective therapies targeting neuroinflammation remain an unmet need, and modulation of the injury microenvironment to induce a comprehensive pro‐regenerative response is an attractive therapeutic approach. Given its crucial role in cell stress and inflammation after SCI, the potential of pharmacologically targeting MAPK‐activated protein kinase‐2 (MK2) to modulate the response of microglia/macrophages after injury is focused. Nanoparticles (NPs) containing an MK2 inhibitor for specific targeting of microglia/macrophages is developed. NPs selectively target and modulate activated microglia/macrophages in vitro and in a rat model of SCI. NPs in the acute injury setting reduce the pro‐inflammatory cytokine IL‐6 and increase the anti‐inflammatory cytokine IL‐10. Importantly, NPs have a significant effect on microglia/macrophage distribution and accumulation, leading to ≈65% reduction of immune cells around the injury. Last, microglia/macrophage populations with activated morphology are significantly reduced compared to resting or ramified cells around the lesion site. This strategy exhibits potential therapeutic efficiency and specificity for local, pharmacologic manipulation of activated microglia/macrophages, and is a versatile tool to manage acute inflammation and glia plasticity after central nervous system trauma.

Cell therapy for the injured spinal cord will rely on combined advances in human stem cell technologies and delivery strategies. Here we encapsulate homotypic spinal cord neural stem cells (scNSCs) in an alginate-based neural ribbon delivery platform. We perform a comprehensive in vitro analysis and qualitatively demonstrate graft survival and injury site retention using a rat C4 hemi-contusion model. Pre-configured neural ribbons are transport-stable modules that enable site-ready injection, and can support scNSC survival and retention in vivo. Neural ribbons offer multifunctionality in vitro including co-encapsulation of the injury site extracellular matrix modifier chondroitinase ABC (chABC), tested here in glial scar models, and ability of cervically-patterned scNSCs to differentiate within neural ribbons and project axons for integration with 3-D external matrices. This is the first extensive in vitro characterization of neural ribbon technology, and constitutes a plausible method for reproducible delivery, placement, and retention of viable neural cells in vivo.

Atherosclerosis is an inflammatory disorder characterized by the progressive thickening of blood vessel walls eventually resulting in acute vascular syndromes. Here, intravenously injectable hybrid nanoconstructs are synthesized for tempering immune cell inflammation locally and systemically. Lipid and polymer chains are nanoprecipitated to form 100 nm spherical polymeric nanoconstructs (SPNs), loaded with methotrexate (MTX) and subsequently labeled with Cu⁶⁴ and fluorescent probes for combined nuclear/optical imaging. Upon engulfment into macrophages, MTX SPNs intracellularly release their anti‐inflammatory cargo significantly lowering the production of proinflammatory cytokine (interleukin 6 and tumor necrosis factor α) already at 0.06 mg mL⁻¹ of MTX. In ApoE^−/− mice, fed with high‐fat diet up to 17 weeks, nuclear and optical imaging demonstrates specific accumulation of SPNs within lipid‐rich plaques along the arterial tree. Histological analyses confirm SPN uptake into macrophages residing within atherosclerotic plaques. A 4‐week treatment with biweekly administration of MTX SPNs is sufficient to reduce the plaque burden in ApoE^−/− mice by 50%, kept on high‐fat diet for 10 weeks. Systemic delivery of MTX to macrophages via multifunctional, hybrid nanoconstructs constitutes an effective strategy to inhibit atherosclerosis progression and induce, potentially, the resorption of vascular lesions.

Multiple formulations of iron oxide nanoparticles (IONPs) have been proposed for enhancing contrast in magnetic resonance imaging (MRI) and for increasing efficacy in thermal ablation therapies. However, insufficient accumulation at the disease site and low magnetic performance hamper the clinical application of IONPs. Here, 20 nm iron oxide nanocubes were assembled into larger nanoconstructs externally stabilized by a serum albumin coating. The resulting assemblies of nanocubes (ANCs) had an average diameter of 100 nm and exhibited transverse relaxivity (r₂ = 678.9 ± 29.0 mM^‒1·s^‒1 at 1.41 T) and heating efficiency (specific absorption rate of 109.8 ± 12.8 W·g^‒1 at 512 kHz and 10 kA·m^‒1). In mice bearing glioblastoma multiforme tumors, Cy5.5-labeled ANCs allowed visualization of malignant masses via both near infrared fluorescent and magnetic resonance imaging. Also, upon systemic administration of ANCs (5 mg_Fe·kg^‒1), 30 min of daily exposure to alternating magnetic fields for three consecutive days was sufficient to halt tumor progression. This study demonstrates that intravascular administration of ANCs can effectively visualize and treat neoplastic masses.

Tumor spheroids constitute an effective in vitro tool to investigate the avascular stage of tumor growth. These three-dimensional cell aggregates reproduce the nutrient and proliferation gradients found in the early stages of cancer and can be grown with a strict control of their environmental conditions. In the last years, new experimental techniques have been developed to determine the effect of mechanical stress on the growth of tumor spheroids. These studies report a reduction in cell proliferation as a function of increasingly applied stress on the surface of the spheroids. This work presents a specialization for tumor spheroid growth of a previous more general multiphase model. The equations of the model are derived in the framework of porous media theory, and constitutive relations for the mass transfer terms and the stress are formulated on the basis of experimental observations. A set of experiments is performed, investigating the growth of U-87MG spheroids both freely growing in the culture medium and subjected to an external mechanical pressure induced by a Dextran solution. The growth curves of the model are compared to the experimental data, with good agreement for both the experimental settings. A new mathematical law regulating the inhibitory effect of mechanical compression on cancer cell proliferation is presented at the end of the paper. This new law is validated against experimental data and provides better results compared to other expressions in the literature.

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 via PET imaging. This unprecedented behavior is ascribed to the unique combination of geometry, surface properties, and mechanical sti...

Growing evidence suggests that multifaceted diseases as cancer can be effectively tackled by hitting simultaneously different biological targets and monitoring patient‐specific responses. Combinatorial therapies, relying on the administration of two or more molecules with different cytotoxic mechanisms, are rapidly progressing in the clinic. Here, 100 nm spherical polymeric nanoconstructs (SPNs) are proposed for the combinatorial treatment of tumors by codelivering a potent antimitotic drug—docetaxel (DTXL)—and a broad spectrum anti‐inflammatory molecule—curcumin (CURC). In vitro, SPNs loaded with DTXL and CURC induce a threefold decrease in IC₅₀ as compared to DTXL‐loaded SPNs. This synergic antitumor effect is also significant in mouse models of glioblastoma multiforme, where, after 22 d of treatment, the combinatorial approach leads to complete disease regression. At 90 d post‐treatment initiation, mice injected with DTXL + CURC SPNs have a 100% survival, whereas only 50% of the DTXL SPN treated mice survive. SPNs are also labeled with radioactive ⁶⁴Cu(DOTA) molecules to document, via PET imaging, the progressive tumor mass shrinkage. Sensitization of DTXL by CURC is associated with NF‐κB downregulation and increased apoptosis. These theranostic nanoconstructs could be used for combinatorial treatment and assessment of therapeutic efficacy in other malignancies.

Iron oxide nanoparticles (IOs) are intrinsically theranostic agents that could be used for magnetic resonance imaging (MRI) and local hyperthermia or tissue thermal ablation. Yet, effective hyperthermia and high MR contrast have not been demonstrated within the same nanoparticle configuration. Here, magnetic nanoconstructs are obtained by confining multiple, ∼ 20 nm nanocubes (NCs) within a deoxy-chitosan core. The resulting nanoconstructs—magnetic nanoflakes (MNFs)—exhibit a hydrodynamic diameter of 156 ± 3.6 nm, with a polydispersity index of ∼0.2, and are stable in PBS up to 7 days. Upon exposure to an alternating magnetic field of 512 kHz and 10 kA m^–1, MNFs provide a specific absorption rate (SAR) of ∼75 W g_Fe^–1, which is 4–15 times larger than that measured for conventional IOs. Moreover, the same nanoconstructs provide a remarkably high transverse relaxivity of ∼500 (mM s)⁻¹, at 1.41T. MNFs represent a first step toward the realization of nanoconstructs with superior relaxometric and ablation properties for more effective theranostics.