Thomas Martens

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Thomas Martens
Laboratory for General Biochemistry and Physical Pharmacy
Ghent University
Harelbekestraat 72
9000 Gent
Belgium
Tel: 0032 9 2648047 (secretary)
Tel: 0032 9 264 8049 (direct)
Fax: 0032 9 2648189
E-mail: Thomas.Martens@UGent.be

Biography

Thomas Martens studied Bioscience Engineering at Ghent University from 2004 – 2009. For his Master’s thesis, under supervision of Dr. Winnok De Vos, he investigated telomere length dynamics using fluorescence microscopy techniques in the lab of Prof. Patric Van Oostveldt. After graduation, he explored the Flemish biotech-industry and worked a short while as a Research Associate for Ablynx. Later on, in 2010, he started his PhD research on ocular gene delivery using advanced light microscopy methods in the Biophotonic Imaging Group. With an engineering background, he tries to develop different assays to quantify and compare the efficiency of nonviral gene delivery to the retinal tissue.

Summary of Research Project(s)

Thomas’s project focuses on retinal gene therapy, i.e. the delivery of therapeutic nucleic acids to the retinal tissue. Getting the therapeutics at the target location remains a difficult hurdle, and different administration routes have been proposed. Intravitreal injection, being the injection in the central part of the eye (the vitreous humour), promises to be a feasible technique in the long run, as well as being very patient compliable. However, one drawback is that the therapeutics aren’t delivered directly to the target tissue (the retina), and therefore the particles should be able to move towards the retina.

Thomas Martens research project 1In the first part of this project, Thomas has developed an ex vivo assay based on advanced microscopy methods (single particle tracking; SPT) to measure the mobility of nanoparticles and gene nanomedicines in intact vitreous humour. This assay, which has been published in Nanomedicine UK, resulted in the establishment of general relationships between nanoparticle characteristics and their intravitreal mobility. To increase this mobility, Thomas is currently investigating the coating of these nanoparticles with hyaluronic acid. In this regard, a collaboration with the group of Elias Fattal in Paris has been set up, who have experience in this coating.

In a second part of the project, Thomas is also focusing on developing assays to measure the transport of nanoparticles across the vitreoretinal interface and the retinal tissue. Firstly, Thomas is trying to develop an ex vivo assay of retinal explants, to visualize in real-time the transport of the nanoparticles across the retinal structures. On the other hand, a collaboration with a French group in Nantes (Prof. Fabienne Rolling) has been discussed to perform in vivo experiments in rodents. This way, we hope to get a clear view of how nanoparticles with different surface characteristics behave at the vitreoretinal interface and inside the retinal tissue.

Finally, once the nanomedicines reach the target cells, they should efficiently deliver their cargo in the intracellular environment. Uptake of such particles usually occurs through endocytosis, leading to the sequestration of the therapeutics in endosomal and lysosomal compartments, rendering them ineffective as a therapeutic. To escape from these endosomal structures is one of the major goals in current drug delivery research. However, to date no clear way of measuring this endosomal escape has been proposed. In collaboration with other researchers in our group, Thomas has tried to visualize the endosomal escape of nanomedicines in retina pigment epithelial cells, and is trying to optimize a general protocol for quantification of endosomal escape.