Nanomalaria

The current activity of the Nanomalaria group is focused on the development of nanomedicine-based systems to be applied to malaria prophylaxis, diagnosis and therapy.

Methods for the diagnosis of malaria can benefit from nanotools applied to the design of microfluidic-based devices for the accurate identification of the parasite’s strain, its precise infective load, and the relative content of the different stages of its life cycle, whose knowledge is essential for the administration of adequate therapies.

Malaria is arguably one of the main medical concerns worldwide because of the numbers of people affected, the severity of the disease and the complexity of the life cycle of its causative agent, the protist Plasmodium spp. The clinical, social and economic burden of malaria has led for the last 100 years to several waves of serious efforts to reach its control and eventual eradication, without success to this day.

With the advent of nanoscience, renewed hopes have appeared of finally obtaining the long sought-after magic bullet against malaria in the form of a nanovector for the targeted delivery of antimalarial drugs exclusively to Plasmodium-infected cells. Nanotechnology can also be applied to the discovery of new antimalarials through single-molecule manipulation approaches for the identification of novel drugs targeting essential molecular components of the parasite.

The benefits and drawbacks of these nanosystems have to be considered in different possible scenarios, including economy-related issues that are hampering the progress of nanotechnology-based medicines against malaria with the dubious argument that they are too expensive to be used in developing areas. Unfortunately, it is true that the application of nanoscience to infectious disease has been traditionally neglected, with most research resources overwhelmingly biased towards other pathologies more prominent in the developed world. Thus, extra ingenuity is demanded from us: malaria-oriented nanomedicines not only need to work spotless; they have to do so in a cost-efficient way because they will be deployed in low-income regions.

The Nanomalaria Group has consolidated its research focus on the development of targeted nanocarriers of antimalarial drugs through the refinement of the nanocapsule structure, its targeting elements, the encapsulated compounds, and the adaptation of this acquired know-how to other parasitic diseases like leishmaniasis.

1.1. Nanocapsule.

1.1.1. Liposomes. We have optimized our immunoliposome-mediated drug delivery to Plasmodium-infected red blood cells (pRBCs) and to non-infected red blood cells as a dual therapeutic/prophylactic antimalarial strategy. Our group has pioneered the use of red blood cells as antimalarial carriers, a strategy that confronts Plasmodium with drugs at the very moment of erythrocyte infection by the pathogen. Using this approach that provided excellent in vivo results where malaria-infected mice were freed of parasites and cured, we have developed new immunoliposomes carrying drug combinations for their targeted delivery to red blood cells and gametocytes, a transmission stage shared between humans and the Anopheles mosquito vector which is a preferred target of malaria eradication efforts.

1.1.2. Polymers. We explore the potential for oral administration formulations of polymeric nanocapsules, which combine into a single chemical structure drug encapsulating capacity, antimalarial activity, low unspecific toxicity, high biodegradability, specific targeting to pRBCs, and affordable synthesis cost.

1. 2. Targeting element.

1.2.1. Heparin. We have shown that heparin has a high binding specificity for pRBCs vs. non-infected red blood cells, a property that is being researched for new antimalarial targeted drug delivery strategies. Heparin exhibits also significant antimalarial capacity, against which no resistance has been described so far, a characteristic that could be harnessed to develop nanocarriers where heparin has a double role as a targeting element and as an antimalarial drug in itself. However, the potent anticoagulant activity of heparin imposes a concentration threshold in blood which hampers its medical use. To overcome this limitation we have explored the synthesis of chemically modified heparin forms maintaining a good antiplasmodial activity but with a reduced anticoagulant capacity.

1.2.2. DNA aptamers. We use the systematic evolution of ligands by exponential enrichment to select DNA aptamers against pRBCs for nanovector targeting and for

1.3. Active principle.

1.3.1. New antimalarial targets. (i)We have identified, cloned and characterized the proteins constituting in Plasmodium the Endosomal Sorting Complex Required for Transport (ESCRT), using molecular biology strategies and nanotechnological femtoinjection techniques in giant unilamellar vesicles, and we are currently exploring their potential as drug targets. (ii) We have identified the presence of aggregation-prone proteins in all stages of malaria parasites in both the human and the mosquito, suggesting that protein aggregates might have a functional role in Plasmodium, and be therefore a druggable target.

1.3.2. New antimalarial drugs. We have discovered the new antiplasmodial styrylpyridinium salt compound YAT2150, which has a number of properties that make it highly interesting as a potential new antimalarial drug, among them: (i) it targets (binds) all P. falciparum stages of the parasite in the vertebrate host and in the mosquito vector; (ii) it fluoresces when interacting with its molecular targets in Plasmodium cells, which makes it a theragnostic agent; (iii) unlike most other current antimalarial drugs which target products of one or a few genes, its presumed mode of action, the inhibition of protein aggregation in the parasite, likely targets multiple proteins, preventing a rapid resistance evolution by the pathogen, (iv) fast-acting drug without cross resistance to chloroquine and artemisinin; (v) it has a low in vitro IC₅₀ below 100 nM against all P. falciparum blood stages, including gametocytes, which indicates its potential as transmission-blocking drug; (vi) it belongs to a chemical family where no other antimalarial has been described up to date, which will prevent the adaptation by the parasite of preexisting resistance mechanisms to currently used drugs (indeed, several chloroquine- and artemisinin-resistant strains are strongly sensitive to YAT2150); (vii) its synthesis is easy and rapid (only two steps), resulting in an attractive activity/cost ratio considering that its main clinical deployment would be in the low per capita income regions where malaria is endemic; (viii) it has a long shelf life (months in solution, years as dry powder) at room temperature. In vivo antimalarial assays are currently ongoing.

1.4. Target disease.

1.4.1. Adaptation to leishmaniasis of the knowledge gained in Plasmodium for the development of nanomedicines.

FIGURE 1. Top: female Anopheles gambiae mosquito. From: John Smart, A Handbook for the Identification of Insects of Medical Importance, British Museum, London, 1948. Bottom: Logo of the NANOpheles project (EURONANOMED III call) coordinated by the Nanomalaria Group.
FIGURE 2. Cover image of the PhD Thesis of Dr. Elisabet Martí Coma-Cros, Investigation of branched and linear polymers as oral delivery systems of antimalarial drugs. 2019. Universitat de Barcelona. Cover design by Mar Martí Coma-Cros.

• Zeiss Primostar microscope
• Shake ‘N’ Stack (Thermo Hybaid) hybridization oven
• Rotatory evaporator RS 3000-V (Selecta)
• Plasmodium falciparum cell cultures

• Prof. Dario Anselmetti
  Universität Bielefeld, Germany. Single molecule force spectroscopy
• Prof. Maria Antònia Busquets
  University of Barcelona, Spain
• Prof. Elisabetta Ranucci
  Università degli Studi di Milano, Italy
• Prof. José Manuel Bautista
  Universidad Complutense de Madrid, Spain
• Dr. Matthias Rottmann
  Swiss Tropical and Public Health Institute, Basel, Switzerland
• Prof. Robert Sinden
  Imperial College London, UK
• Dr. Israel Molina
  Hospital Universitari Vall d’Hebron, Barcelona
• Prof. José Luis Serrano
  Instituto de Nanociencia de Aragón, Zaragoza
• Prof. Johan Engbersen
  University of Twente, The Netherlands
• Dr. Santiago Imperial
  University of Barcelona, Spain
• Dr. Eduardo Prata Vilanova
  Universidade Federal do Rio de Janeiro, Brazil. Exploration of sulfated polysaccharides of marine origin as antimalarials
• Dr. Maria Manconi
  Università de Cagliari, Sardinia, Italy. Liposome technology
• Dr. Krijn Paaijmans
  CRESIB, Barcelona, Spain
• Dr. Ellen Faszewski
  Wheelock College, Boston, USA. Marine sponge cell adhesion
• Prof. Bernard Degnan
  University of Brisbane, Australia
• Dr. Francisco J. Muñoz
  Parc de Recerca Biomèdica de Barcelona, Spain. Amyloid diseases
• Dr. Inga Siden-Kiamos
  FORTH Institute of Molecular Biology & Biotechnology, Greece. Development of the malaria parasite within the mosquito
• Prof. Salvador Ventura
  Universitat Autònoma de Barcelona, Bellaterra, Spain. Aggregative proteins
• Dr. Juan José Valle-Delgado
  Aalto University, Helsinki, Finland. Atomic force microscopy
• Prof. Mats Wahlgren
  Karolinska Institutet, Stockholm, Sweden
• Dr. Fatima Nogueira
  Instituto de Higiene e Medicina Tropical, Lisboa, Portugal. Antimalarial drug assays in Plasmodium-infected mosquitoes and mice. 
• Dr. Christian Grandfils
  University of Liège, Belgium. Biomaterials research. 
• Salvador Borros
  Institut Químic de Sarrià, Barcelona. Materials Chemistry 
• Paula Gomes
  Universidade do Porto, Portugal. Development of new antimalarial drugs
• José Antonio García Salcedo
  Instituto de Parasitología y Biomedicina “López-Neyra”, Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain. Synthesis of chitosan nanoparticles
• Eva Baldrich
  Hospital Universitari Vall d’Hebron, Barcelona. Malaria diagnosis
• Kim Williamson
  Uniformed Services University of the Health Sciences, Bethesda, USA. Basic biology of bacterial, viral, and parasite diseases
• Teresa Sierra
  Instituto de Nanociencia de Aragón, Zaragoza, Spain. Dendrimer technology 
• Jos Paulusse
  University of Twente, The Netherlands. Encapsulation of peptides in tailor-made multifunctionalized nanocarriers and polyamidoamine-derived nanogels