Daniele Di Mascolo

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 via 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.

Rosiglitazone-loaded nanospheres for modulating macrophage-specific inflammation in obesity.

PPARγ nuclear receptor agonists have been shown to attenuate macrophage inflammatory responses implicated in the metabolic complications of obesity and in atherosclerosis. However, PPARγ agonists currently in clinical use, including rosiglitazone (RSG), are often associated with severe side effects that limit their therapeutic use. Here, 200nm PLGA/PVA nanospheres were formulated for the systemic delivery of RSG specifically to macrophages. RSG was encapsulated with over 50% efficiency in the hydrophobic PLGA core and released specifically within the acidifying macrophage phagosomes. In bone marrow derived macrophages, RSG-loaded nanoparticles (RSG-NPs) induce a dose dependent upregulation (1.5 to 2.5-fold) of known PPARγ target genes, with maximal induction at 5μM; and downregulate the expression of genes related to the inflammatory process, with a maximum effect at 10μM. In Ldlr(-/-) mice fed high fat diet, treatment with RSG-NPs alleviated inflammation in white adipose tissue and liver but, unlike treatment with free RSG, did not alter genes associated with lipid metabolism or cardiac function, indicating a reduction in the RSG side effect profile. These biocompatible, biodegradable RSG-NPs represent a preliminary step towards the specific delivery of nuclear receptor agonists for the treatment of macrophage-mediated inflammatory conditions associated with obesity, atherosclerosis and other chronic disease states.

Modulating the vascular behavior of metastatic breast cancer cells by curcumin treatment

The spreading of tumor cells to secondary sites (tumor metastasis) is a complex process that involves multiple, sequential steps. Vascular adhesion and extravasation of circulating tumor cells (CTCs) is one, critical step. Curcumin, a natural compound extracted from Curcuma longa, is known to have anti-tumoral, anti-proliferative, anti-inflammatory properties and affect the expression of cell adhesion molecules, mostly by targeting the NF-κB transcription factor. Here, upon treatment with curcumin, the vascular behavior of three different estrogen receptor negative (ER–) breast adenocarcinoma cell lines (SK-BR-3, MDA-MB-231, MDA-MB-468) is analyzed using a microfluidic system. First, the dose response to curcumin is characterized at 24, 48, and 72 h using a XTT assay. For all three cell lines, an IC50 larger than 20 µM is observed at 72 h; whereas no significant reduction in cell viability is detected for curcumin concentrations up to 10 µM. Upon 24 h treatment at 10 µM of curcumin, SK-BR3 and MDA-MB-231 cells show a decrease in adhesion propensity of 40% (p = 0.02) and 47% (p = 0.001), respectively. No significant change is documented for the less metastatic MDA-MB-468 cells. All three treated cell lines show a 20% increase in rolling velocity from 48.3 to 58.7 µm/s in SK-BR-3, from 64.1 to 73.77 µm/s in MDA-MB-231, and from 57.5 to 74.4 µm/s in MDA-MB-468. Collectively, these results suggest that mild curcumin treatments could limit the metastatic potential of these adenocarcinoma cell lines, possibly by altering the expression of adhesion molecules, and the organization and stiffness of the cell cytoskeleton. Future studies will elucidate the biophysical mechanisms regulating this curcumin-induced behavior and further explore the clinical relevance of these findings.

Spherical polymeric nanoconstructs for combined chemotherapeutic and anti-inflammatory therapies

Nanoparticles can simultaneously deliver multiple agents to cancerous lesions enabling de facto combination therapies. Here, spherical polymeric nanoconstructs (SPNs) are loaded with anti-cancer - docetaxel (DTXL) - and anti-inflammatory - diclofenac (DICL) - molecules. In vitro, combination SPNs kill U87-MG cells twice as efficiently as DTXL SPNs, achieving a IC50 of 90.5nM at 72h. Isobologram analysis confirms a significant synergy (CI=0.56) between DTXL and DICL. In mice bearing non-orthotopic glioblastoma multiforme tumors, combination SPNs demonstrate higher inhibition in disease progression. At 70days post treatment, the survival rate of mice treated with combination SPNs is of about 70%, against a 40% for DTXL SPNs and 0% for free DTXL. Combination SPNs dramatically inhibit COX-2 expression, modulating the local inflammatory status, and increase Caspase-3 expression, which is directly related to cell death. These results suggest that the combination of anti-cancer and anti-inflammatory molecules constitutes a potent strategy for inhibiting tumor growth.

Ameliorating Amyloid-β Fibrils Triggered Inflammation via Curcumin-Loaded Polymeric Nanoconstructs

Inflammation is a common hallmark in several diseases, including atherosclerosis, cancer, obesity, and neurodegeneration. In Alzheimer’s disease (AD), growing evidence directly correlates neuronal damage with inflammation of myeloid brain cells, such as microglia. Here, polymeric nanoparticles were engineered and characterized for the delivery of anti-inflammatory molecules to macrophages stimulated via direct incubation with amyloid-β fibers. 200 nm spherical polymeric nanoconstructs (SPNs) and 1,000 nm discoidal polymeric nanoconstructs (DPNs) were synthesized using poly(lactic-co-glycolic acid) (PLGA), polyethylene glycol (PEG), and lipid chains as building blocks. First, the internalization propensity in macrophages of both nanoparticles was assessed via cytofluorimetric and confocal microscopy analyses, demonstrating that SPNs are by far more rapidly taken up as compared to DPNs (99.6 ± 0.11 vs 14.4 ± 0.06%, within 24 h). Then, Curcumin-loaded SPNs (Curc-SPNs) were realized by encapsulating Curcumin, a natural anti-inflammatory molecule, within the PLGA core of SPNs. Finally, Curc-SPNs were shown to diminish up to 6.5-fold the production of pro-inflammatory cytokines—IL-1β; IL-6, and TNF-α—in macrophages stimulated via amyloid-β fibers. Although more sophisticated in vitro models and systematic analyses on the blood–brain barrier permeability are critically needed, these findings hold potential in the development of nanoparticles for modulating inflammation in AD.

Smart nanoconstructs for theranostics in cancer and cardiovascular diseases

Abstract The last 40 years have witnessed the rapid development of novel strategies to enhance the systemic administration of molecular agents for therapy and imaging. As such, “drug delivery” has become one of the most challenging and scientifically advanced fields of research. Nanoparticles for the systemic delivery of therapeutic and contrast agents have been tested in preclinical studies for the cure and early detection of cancer, cardiovascular and neurodegenerative diseases [1–4]. Compared to conventional molecular agents, drug delivery systems can offer several advantages. Nanoparticles can improve the bioavailability, biodistribution, and longevity in the circulation of the carried molecules. Furthermore, they offer the opportunity of preserving, over long times, the tissue concentration of the drug molecules within proper therapeutic ranges and protect them from enzymatic degradation [5]. Overall, these improvements allow for an enhancement in drug accumulation at the biological target and a reduction of the off-site effects, as compared to the freely administered molecular formulation. In this chapter, first the design and fabrication of polymeric nanoconstructs for the smart delivery of therapeutic and imaging agents will be presented. Then, the role of multimodal imaging and theranostics will be reviewed providing examples available in the open literature and produced by the authors. Finally, the role of in vitro testing and in silico computational modeling in the optimization of polymeric nanoconstructs will be assessed.

Hierarchical Microplates as Drug Depots with Controlled Geometry, Rigidity, and Therapeutic Efficacy

A variety of microparticles have been proposed for the sustained and localized delivery of drugs with the objective of increasing therapeutic indexes by circumventing filtering organs and biological barriers. Yet, the geometrical, mechanical, and therapeutic properties of such microparticles cannot be simultaneously and independently tailored during the fabrication process to optimize their performance. In this work, a top-down approach is employed to realize micron-sized polymeric particles, called microplates (μPLs), for the sustained release of therapeutic agents. μPLs are square hydrogel particles, with an edge length of 20 μm and a height of 5 μm, made out of poly(lactic- co-glycolic acid) (PLGA). During the synthesis process, the μPL Youngs modulus can be varied from 0.6 to 5 MPa by changing the PLGA amounts from 1 to 7.5 mg, without affecting the μPL geometry while matching the properties of the surrounding tissue. Within the porous μPL matrix, different classes of therapeutic payloads can be incorporated including molecular agents, such as anti-inflammatory dexamethasone (DEX), and nanoparticles containing imaging and therapeutic molecules themselves, thus originating a truly hierarchical platform. As a proof of principle, μPLs are loaded with free DEX and 200 nm spherical polymeric nanoparticles, carrying DEX molecules (DEX-SPNs). Electron and fluorescent confocal microscopy analyses document the uniform distribution and stability of molecular and nanoagents within the μPL matrix. This multiscale, hierarchical microparticle releases DEX for at least 10 days. The inclusion of DEX-SPNs serves to minimize the initial burst release and modulate the diffusion of DEX molecules out of the μPL matrix. The biopharmacological and therapeutic properties together with the fine tuning of geometry and mechanical stiffness make μPLs a unique polymeric depot for the potential treatment of cancer, cardiovascular, and chronic, inflammatory diseases.

Nano-Particles for Biomedical Applications

Nanoparticles (NP s) are extremely small particulates with an average size that ranges from a micron or less to a few nanometers. The large majority of NPs necessitate nanotechnology methods for their production. The size of NPs may vary over a significant range, which underlies their scientific potential in that NPs may help cross the bridge between bulk materials and molecular structures. More importantly, NPs are (nano)tech products and thus, in contrast to natural systems, they can be designed and engineered. On directly interacting with cells, including the structures of cells, their machinery and their waste products, NPs represent an unprecedented tool for addressing specific biological problems. In this chapter, we will briefly review some recent advances in nanoparticle research for biomedical applications, ranging from mesoporous silicon particles to gold and silver nanoparticles and polymeric nanocarriers for therapeutic, diagnosis, or theranostic (therapeutics + diagnosis) applications. We will offer a description of how, at the current state of the art, similar nanomedicine platforms are realized.