Latest research

from my lab

Food engineering

Encapsulation of perishable bioactive molecules has become a standard process in the food industry. Beads in the millimeter size range may offer technological advantage over smaller particles and nano-structured materials for encapsulation purposes because of higher volume to surface ratios, but their size might seriously affect the sensory properties of the final edible products. We investigated the rheological properties of individual beads composed of chitosan cross-linked with sodium tripolyphosphate. and we exploited a recently-developed nonlinear model to analyse mechanical data collected during the stress phase and estimate viscoelastic parameters. Two representative bioactive food phenolic compounds, i.e. chlorogenic acid and catechin, were also encapsulated into the beads. Encapsulation of chlorogenic acid and catechin dramatically altered the viscoelastic behaviour of the particles in a similar way. Our results pave the way for a more accurate evaluation of sensory characteristics of novel functional foods incorporating particle carriers for bioactive molecules.

Pharmaceutical engineering

Radiation-induced fibrosis is a serious long-lasting side effect of radiation therapy. Central to this condition is the role of macrophages that, activated by radiation-induced reactive oxygen species and tissue cell damage, produce pro-inflammatory cytokines, such as transforming growth factor beta (TGFβ). This, in turn, recruits fibroblasts at the site of the lesion that initiates fibrosis. We investigated whether astaxanthin, an antioxidant molecule extracted from marine and freshwater organisms, could help control macrophage activation. To this purpose, we encapsulated food-grade astaxanthin from Haematococcus pluvialis into micrometer-sized whey protein particles to specifically target macrophages that can uptake material within this size range by phagocytosis. The data show that astaxanthin-loaded microparticles are resistant to radiation, are well-tolerated by J774A.1 macrophages, induce in these cells a significant reduction of intracellular reactive oxygen species and inhibit the release of active TGFβ as evaluated in a bioassay with transformed MFB-F11 fibroblasts. Micro-encapsulation of bioactive molecules is a promising strategy to specifically target phagocytic cells and modulate their own functions.

Pentoxifylline, a drug currently used for the treatment of muscle pain resulting from peripheral artery disease, amplifies the effects of astaxanthin microparticles on J774A.1 macrophages. Combination treatments with pentoxifylline and encapsulated astaxanthin might therefore reduce the risk of RIF in cancer patients.

collaborations

Stochastic models of complex living systems

Experiments in predator-prey systems show the emergence of long-term cycles. Deterministic model typically fails in capturing these behaviors, which emerge from the microscopic interplay of individual based dynamics and stochastic effects. However, simulating stochastic individual based models can be extremely demanding, especially when the sample size is large. Hence, we have proposed an alternative simulation approach, whose computation cost is lower than the one of the classic stochastic algorithms. Due to the flexible formulation of our ensemble stochastic algorithm it can be used not only to simulate the microscopic dynamics of interacting biological entities, but further generalized to other agent-based models, with different interaction dynamics and different macroscopic limiting models.

Data analysis and statistics

Untargeted metabolomics investigation on selenite reduction to elemental selenium by Bacillus mycoides SeITE01. A time-course approach was used to monitor both cell pellet and cell free spent medium metabolites in SeITE01 cells treated or not with oxyanion selenite. The analysis of collected multivariate data sets was a statistical challenge, and I contributed with some calculations carried out with the software R. The identified metabolites were consistent with the hypothesis of intracellular accumulation of osmo-protective solutes and antioxidants, the activation of ROS scavengers, as well as compounds that participate in stabilizing the cytoplasmic membrane. Furthermore, in the cell free spent medium (extracellular), there was a change in metabolites related to oxidative stress, signaling, stress linked amino acids and metabolites involved in modifications of bacterial membranes lipids and cell walls.