Microbial biosensors to monitor the encapsulation effectiveness of Doxorubicin in chimeric advanced Drug Delivery Nano Systems: A calorimetric approach Konstantinos Gardikis b , Marco Signorelli a , Chiara Ferrario a , Alberto Schiraldi a , Maria Grazia Fortina a , Sophia Hatziantoniou b , Costas Demetzos b , Dimitrios Fessas a, * a Department of Food, Environmental and Nutritional Sciences (DeFENS), Università degli Studi di Milano, Via Celoria 2, 20133 Milano, Italy b Department of Pharmaceutical Technology, University of Athens, School of Pharmacy, Panepistimioupolis, Zografou, 15771, Athens, Greece A R T I C L E I N F O Article history: Received 8 September 2016 Received in revised form 9 November 2016 Accepted 10 November 2016 Available online 11 November 2016 Keywords: Doxorubicin Drug delivery Liposomes Dendrimers Isothermal titration calorimetry (ITC) Lactobacillus helveticus A B S T R A C T The release of the anticancer drug doxorubicin (DOX) incorporated in a new drug carrier, namely a chimeric nanosystem formed by liposomes and dendrimers, was studied following the influence of the drug on the growth kinetics of the Lactobacillus helveticus bacterium, that would mimic the intestinal microflora. The bacterial growth was followed at 37  C by means of Isothermal Titration Calorimetry (ITC) and the method was assessed to monitor the overall effect of the delivered drug obtaining simple objective parameters to define the encapsulation effectiveness of the system, discriminating dose effects even in cases of very low release. Traditional microbiological investigations and in vitro release tests were also performed in parallel for validation. The achieved results suggest that L. helveticus is an excellent candidate as biosensor to assess the sealing effectiveness of these DOX drug carriers through ITC investigations. This approach can be extended for quantitative comparison of drug delivery systems with the same drug inserted in other supramolecular bodies for quantitative comparison. The peculiar results for the DOX drug carrier system investigated, indicate also that, the use of hydrophilic dendrimers in this case, produce a high sealing effect that seems promising in terms of the intestinal flora protection. ã 2016 Elsevier B.V. All rights reserved. 1. Introduction The research on drug carriers garnered a substantial improve- ment thanks to the achievements of nanotechnology. New drug carriers (liposomes, dendrimers etc.) with a size of some tenth of nanometers offer the possibility to increase the therapeutic index (TI) of known or new drugs by improving their effectiveness, diminishing their toxicityagainst physiological tissues and achieving controlled therapeutic levels for wide time spans (Massing and Fuxius, 2000; Allen et al. 2006; Hatziantoniou and Demetzos, 2006; Wagner, 2007; Park, 2007; Schiffelers and Storm, 2008; Manocha and Margaritis, 2010; Lallana et al. 2012; Liu et al. 2014; Haj Sleiman et al., 2015; Demetzos, 2015a, 2015b; Szulc et al. 2015). In particular, in the recent years, nanoparticles formed by combining liposomes and dendrimers (Gardikis et al., 2010a, 2010b; Purohit et al., 2001; Khopade et al., 2002; Moraes et al., 2008; Ballut et al., 2009; Tekade et al., 2009; Wrobel et al., 2015; Papagiannaros et al., 2005) were used as carriers of Doxorubicin (DOX), an anthracycline antibiotic for chemotherapy against a wide number of cancers, carcinomas and soft tissue sarcomas (Abraham et al., 2005). These new formulations have recently been categorized as chimeric advanced Drug Delivery nano-Systems (chi-aDDnS) due to the combination of two independent technologies for producing an overall system with unique properties (Gardikis et al., 2010c; Pippa et al., 2014) which could be advantageous compared to conventional liposomal carriers. Recent studies demonstrate that different type of dendrimers with different molecular size and branching degree, that are able to trigger a phase separation within the lipid bilayer, push the chi- Abbreviations: chi-aDDnS, chimeric advanced Drug Delivery nano-Systems; ITC, Isothermal Titration Calorimetry; DOX, doxorubicin; Lactobacillus helveticus, L. helveticus. * Corresponding author at: Università di Milano, DeFENS, Via Celoria 2, 20133 Milano Italy. E-mail address: dimitrios.fessas@unimi.it (D. Fessas). http://dx.doi.org/10.1016/j.ijpharm.2016.11.033 0378-5173/ã 2016 Elsevier B.V. All rights reserved. International Journal of Pharmaceutics 516 (2017) 178–184 Contents lists available at ScienceDirect International Journal of Pharmaceutics journa l home page : www.e lsevier.com/loca te/ijpharm