Category: Micro- and Nanotechnologies
Malignant melanoma is a skin cancer characterized by high aggressiveness and resistance to various therapeutic approaches. Nonetheless, combined therapy may provide a great promise in the multidrug resistance MDR cancer treatments. So far in the area of combination therapy extremely little research has been conducted with application of Lab-on-a-chip systems. Herein we report on the therapeutic efficiency of a novel nanoscale drug delivery system (nDDS), that combines chemotherapy and photodynamic therapy (PDT) into one single platform. Thus, two active compounds - daunorubicin and hydrophobic photosensitizer IR-768 – were sufficiently co-encapsulated in polymeric micelles (PMs) of mPEG-b-PLGA. Co-delivery of dual therapeutic platform PMs/IR-768/DRB allowed to achieve synergistic anticancer capacity, which was investigated using a newly developed microfluidic system for cell monoculture, controllable co-culture and mixed culture.
The fabricated PMs, imaged by AFM and DLS (DH≈25nm) can be efficiently internalized by melanoma A375 and MeWo cells through endocytosis, thereby leading to higher cellular uptake than in non-malignant HaCaT. Moreover, MTT assay showed, that from a native IR-768, IR-768 loaded in mPEG-b-PLGA PMs and PMs/IR-768/DRB, a strong phototoxic effect was exhibited only by a dual therapeutic platform (the viability of A375 decreased dramatically to 10% at 0.5µM concentration of IR-768 in PMs).
The magnitude of chemo-PDT-toxicity was subsequently evaluated using newly designed microchip. The microsystem enables, in contrast to our previous work, to create a co-culture in a controllable manner due to the hydrodynamic focusing and strictly defined lengths of the transverse channels. This feature of the microsystem was visualized utilizing Cell Trackers™. HaCaT, MeWo and A375 cells were labelled (red, violet, green, respectively) prior to loading into the microsystem. It was possible to obtain both co-culture where cells were not mixed during loading as well as the mixed one. The ratio of mixing of non-malignant and tumor cells depends on the applied fluid flow rates. Furthermore, the geometry of the microdevice was designed to fit a multiwell plate reader's measuring system, which further enhances the efficiency of the conducted study. Consequently, cell viability assay using commercially available fluorescent dyes can be carried out. After performing photodynamic reaction in the microsystem, A375 cell viability decreased to 30% at 1µM concentration of IR-768 in PMs. It has to be emphasized that similar effect was achieved in a macroscale at merely 0.25µM of photosensitizer concentration in PMs. This underlines the need for screening a novel nDDS using the microfluidic systems.
Summarizing, newly developed targeted MCs/IR-768/DRB nanoplatforms were investigated using a Lab-on-a-chip system. The phototoxic properties show very potent anticancer activity against A375 metastatic melanoma. Our study suggests the great potential of polymeric micelles for combined chemo-PDT therapy to overcome MDR of highly aggressive melanoma.
ACKNOWLEDGEMENTS This work has been supported by a statutory activity subsidy from the Polish Ministry of Science and Higher Education for the Faculty of Chemistry of Warsaw University of Technology and Faculty of Chemistry of Wrocław University of Science and Technology. The authors wish to thank Kamil Żukowski for preparation of a holder and mold for PDMS casting.
Katarzyna Tokarska– Ph.D. student, Warsaw University of Technology, Warsaw, Mazowieckie, Poland
Warsaw University of Technology
Warsaw, Mazowieckie, Poland
Katarzyna Tokarska was born in 1990. She graduated with a master's degree in chemistry with excellent grade dealing with a project concerning cell adhesion studies. Currently she is a 4 year Ph.D. student at Warsaw University of Technology under the guidance of D.Sc. Michał Chudy. She is also a member of Chemical Sensors Research Group and European Society of Photobiology. Her research focuses on the application of nanoparticles for photodynamic therapy of cancer using Lab-on-a-chip systems.