Biology subjects

La Regina, A.

Publications and source records attributed to La Regina, A..

4 recordsLinked to original sources

bioRxiv2025

Harnessing Dynamic Cell Responses to Optimise Pluripotency Protocols

Pluripotent stem cells have a high potential for research and development applications in biomedicine. They are undifferentiated cells capable of unlimited self-renewal and maintenance of pluripotency, yet can be induced to differentiate into specific cell types through defined cues. Various protocols have been proposed to maintain mouse embryonic stem cells (mESCs) in the pluripotent state; state of the art cell culture protocols are based on serum-free media, and continuous provision of drugs inhibiting pathways associated to differentiation. We explore here the possibility to avoid continuous drug exposure. First, we employ an external feedback control microfluidics/microscopy platform to steer the expression of a pluripotency reporter. Control experiments show a significant delay in cell response to drugs; these dynamics are confirmed by flow-cytometry open-loop experiments. We then harness such delays to design novel culture protocols with limited cell exposure to small-molecule inhibitors; in so doing, we reduce cell exposure to drug, but we maintain pluripotency. Our results suggest new approaches to design cell culture protocols based on the quantitative analysis and control of cellular dynamics.

synthetic biology↗

bioRxiv2022

Development of a single layer microfluidic device for dynamic stimulation, culture and imaging of mammalian cells

The possibility to tightly control the cellular microenvironment within microfluidic devices represents an important step forward precision analysis of cellular phenotypes in vitro. In particular, microfluidic platforms that allow both long-term mammalian cell culture and dynamic modulation of the culture environment can support quantitative studies of cells responses to drugs. Here, we report the design and testing of a novel microfluidic device of easy production (single Polydimethylsiloxane layer), which integrates a micromixer with vacuum-assisted cell loading for long-term mammalian cell culture and dynamic mixing of 4 different culture media. Finite element modelling was used to predict the flow rates and device dimensions to achieve diffusion-based fluid mixing. The device showed efficient mixing and dynamic exchange of media in the cell trapping chambers. This work represents the first attempt to integrate single layer microfluidic mixing devices with vacuum-assisted cell loading systems for mammalian cell culture and dynamic stimulation.

bioengineering↗

bioRxiv2020

Cyber-yeast: Automatic synchronisation of the cell cycle in budding yeast through closed-loop feedback control

The cell cycle is the process by which eukaryotic cells replicate. Yeast cells cycle asynchronously with each cell in the population budding at a different time. Although there are several experimental approaches to "synchronise" cells, these work only in the short-term. Here, we built a cyber-genetic system to achieve long-term synchronisation of the cell population, by interfacing genetically modified yeast cells with a computer by means of microfluidics to dynamically change medium, and a microscope to estimate cell cycle phases of individual cells. The computer implements a "controller" algorithm to decide when, and for how long, to change the growth medium to synchronise the cell-cycle across the population. Our work builds upon solid theoretical foundations provided by Control Engineering. In addition to providing a new avenue for yeast cell cycle synchronisation, our work shows that computers can automatically steer complex biological processes towards desired behaviours similarly to what is currently done with robots and autonomous vehicles.

synthetic biology↗

bioRxiv2019

Feedback control promotes synchronisation of the cell-cycle across a population of yeast cells

The periodic process of cell replication by division, known as cell-cycle, is a natural phenomenon occurring asynchronously in any cell population. Here, we consider the problem of synchronising cell-cycles across a population of yeast cells grown in a microfluidics device. Cells were engineered to reset their cell-cycle in response to low methionine levels. Automated syringes enable changing methionine levels (control input) in the microfluidics device. However, the control input resets only those cells that are in a specific phase of the cell-cycle (G1 phase), while the others continue to cycle unperturbed. We devised a simplified dynamical model of the cell-cycle, inferred its parameters from experimental data and then designed two control strategies: (i) an open-loop controller based on the application of periodic stimuli; (ii) a closed-loop model predictive controller (MPC) that selects the sequence of control stimuli which maximises a synchronisation index. Both the proposed control strategies were validated in-silico, together with experimental validation of the open-loop strategy.

synthetic biology↗