Paolo Blasi

Nanoparticles in biomedicine: New insights from plant viruses

In recent years there has been an outburst of interest regarding the employment of nanoparticles for biomedical applications. Among the different types, such as metallic, organic, biological and hybrid systems, virus based nanoparticles have become a popular field of research. Viruses are able to form organized structures by molecular self assembly of repetitive building blocks, which implies non covalent interactions of protein monomers to form the quaternary structure of viral capsids. Plant virus based systems, in particular, are among the most advanced and exploited for their potential use as bioinspired structured nanomaterials and nanovectors. Plant viruses have a size particularly suitable for nanoscale applications and can offer several advantages. In fact, they are structurally uniform, robust, biodegradable and easy to produce. Moreover, many are the examples regarding functionalization of plant virus based nanoparticles by means of modification of their external surface and by loading cargo molecules into their internal cavity. This plasticity in terms of nanoparticles engineering is the ground on which multivalency, payload containment and targeted delivery can be fully exploited. This review aims primarily to summarize the most important plant virus based nanoparticles systems through their recent applications in biomedicine, such as epitope display for vaccine development and targeted delivery for diagnosis or therapy. In addition, their production in the most commonly used plant propagation and expression systems will be also reviewed.

In vitro and in vivo toxicity evaluation of plant virus nanocarriers

The use of biological self-assembling materials, plant virus nanoparticles in particular, appears very intriguing as it allows a great choice of symmetries and dimensions, easy chemical and biological engineering of both surface and/or internal cavity as well as safe and rapid production in plants. In this perspective, we present an initial evaluation of the safety profile of two structurally different plant viruses produced in Nicotiana benthamiana L. plants: the filamentous Potato virus X and the icosahedral Tomato bushy stunt virus. In vitro haemolysis assay was used to test the cytotoxic effects, which could arise by pVNPs interaction with cellular membranes, while early embryo assay was used to evaluate toxicity and teratogenicity in vivo. Data indicates that these structurally robust particles, still able to infect plants after incubation in serum up to 24h, have neither toxic nor teratogenic effects in vitro and in vivo. This work represents the first safety-focused characterization of pVNPs in view of their possible use as drug delivery carriers.

Oral drug therapy in elderly with dysphagia: between a rock and a hard place!

Demographic indicators forecast that by 2050, the elderly will account for about one-third of the global population. Geriatric patients require a large number of medicines, and in most cases, these products are administered as solid oral solid dosage forms, as they are by far the most common formulations on the market. However, this population tends to suffer difficulties with swallowing. Caregivers in hospital geriatric units routinely compound in solid oral dosage forms for dysphagic patients by crushing the tablets or opening the capsules to facilitate administration. The manipulation of a tablet or a capsule, if not clearly indicated in the product labeling, is an off-label use of the medicine, and must be supported by documented scientific evidence and requires the patient’s informed consent. Compounding of marketed products has been recognized as being responsible for an increased number of adverse events and medical errors. Since extemporaneous compounding is the rule and not the exception in geriatrics departments, the seriousness and scope of issues caused by this daily practice are probably underestimated. In this article, the potential problems associated with the manipulation of authorized solid oral dosage forms are discussed.

Acoustic spectroscopy: A powerful analytical method for the pharmaceutical field?

Acoustics is one of the emerging technologies developed to minimize processing, maximize quality and ensure the safety of pharmaceutical, food and chemical products. The operating principle of acoustic spectroscopy is the measurement of the ultrasound pulse intensity and phase after its propagation through a sample. The main goal of this technique is to characterise concentrated colloidal dispersions without dilution, in such a way as to be able to analyse non-transparent and even highly structured systems. This review presents the state of the art of ultrasound-based techniques in pharmaceutical pre-formulation and formulation steps, showing their potential, applicability and limits. It reports in a simplified version the theory behind acoustic spectroscopy, describes the most common equipment on the market, and finally overviews different studies performed on systems and materials used in the pharmaceutical or related fields.

Artificial apolipoprotein corona enables nanoparticle brain targeting

Many potential therapeutic compounds for brain diseases fail to reach their molecular targets due to the impermeability of the blood-brain barrier, limiting their clinical development. Nanotechnology-based approaches might improve compounds pharmacokinetics by enhancing binding to the cerebrovascular endothelium and translocation into the brain. Adsorption of apolipoprotein E4 onto polysorbate 80-stabilized nanoparticles to produce a protein corona allows the specific targeting of cerebrovascular endothelium. This strategy increased nanoparticle translocation into brain parenchyma, and improved brain nanoparticle accumulation 3-fold compared to undecorated particles (119.8 vs 40.5 picomoles). Apolipoprotein decorated nanoparticles have high clinical translational potential and may improve the development of nanotechnology-based medicine for a variety of neurological diseases.

Nanoparticles at the neurovascular unit: In vitro and in vivo studies to assess the blood-brain barrier permeability and function

Objective: Nanoparticle-based imaging and nanocarriers therapies have emerged as essential tools for many fields of modern medicine, in order to track the fate of cells and optimize drug delivery. Up to now, however, there are only few reports on the effect of nanocarriers of different types on oxygen delivery, even though this would be of great interest for the design of high impact therapies in several cardiovascular diseases (CVDs). In particular, Cyclodextrin Nanosponges (C-NS) can be envisioned as innovative tools to improve the delivery of oxygen in a controlled manner in CVDs. Methods: We tested oxygenated C-NS (OX-C-NS) at different concentrations (0.2, 2 and 20 μg/ml) for their capability to reduce cell mortality during hypoxia and reoxygenation (H/R) protocols. For comparative purpose, we also tested “blank materials” (C-NS filled with nitrogen gas without oxygen) and the effects of C-NS in Normoxia. To test the effectiveness of C-NS, we used H9c2, a cardiomyoblast cell line derived from rat heart, exposed to Normoxia (5% CO2 and 21% O2) or Hypoxia (5% CO2 and 95%N2) in a Hypoxic Chamber. The cellular mortality was measured with MTT assay. Results: In Normoxia, regardless of OX-C-NS formulation, the H9c2 cells displayed a tendency to an increased proliferation, which seemed somewhat correlated to the concentration of OX-C-NS used. The different concentration of OX-C-NS, applied before Hypoxia, induced a significant reduction of cell mortality compared to C-NS without oxygen. Also, the application of OX-C-NS at the beginning of reoxygenation induced a marked reduction of cell death. Conclusions: OX-C-NS may induce H9c2 cell proliferation in Normoxia and may protect H9c2 from H/R injury in vitro. The administration of oxygen in a controlled manner during or after an ischemic event may be an innovative approach for reduction of Ischemia/Reperfusion injury, with consequent reduction of chronic CVDs. Our preliminary results, and in particular the observation of a remarkable efficacy in reoxygenation, suggest an interesting potentiality for medical application of C-NS during the treatment of myocardial infarction. Further studies are required to ascertain the protective potential of C-NS on cardiac I/R injury under in vivo conditions.

Innovative Nanoparticles Enhance N-Palmitoylethanolamide Intraocular Delivery

Nanostructured lipid carriers (NLCs) loaded with palmitoylethanolamide (PEA) were formulated with the aim to enhance ocular bioavailability of PEA, particularly to the back of the eye. Technological characterization (e.g., size, charge) of NLC loaded with PEA formulation (PEA-NLC) was performed, and NLC morphology was characterized by electron microscopy. Ocular pharmacokinetic study, after topical administration of the formulation, was carried out in rabbit eye. Ultra-high performance liquid chromatography tandem mass spectrometry analysis was carried out to detect PEA levels in ocular tissues. Finally, the ocular tolerability of PEA-NLC formulation was assessed in rabbit eye. The novel formulation significantly increased PEA levels in ocular tissues compared to PEA suspension. Vitreous and retinal levels of PEA were significantly higher in the group treated with PEA-NLC formulation versus PEA suspension (PEA-NLC Cmax 5919 ± 541 pmol/g and 315 ± 70 pmol/g in vitreous and retina, respectively). The PEA-NLC formulation was characterized by high stability and robust ocular bioavailability. Therefore, this innovative formulation may be useful in clinical practice to manage retinal diseases.

Nanoparticles at the neurovascular unit: in vitro and in vivo studies to assess the blood-brain barrier permeability and function

Margarethe Geiger; Nandu Goswami; Michael Fischer; Markus Ritter; Marjan Slak Rupnik; Johann Wojta