Issue 4, 2018

Flocculation on a chip: a novel screening approach to determine floc growth rates and select flocculating agents

Abstract

Flocculation is a key purification step in cell-based processes for the food and pharmaceutical industry where the removal of cells and cellular debris is aided by adding flocculating agents. However, finding the best suited flocculating agent and optimal conditions to achieve rapid and effective flocculation is a non-trivial task. In conventional analytical systems, turbulent mixing creates a dynamic equilibrium between floc growth and breakage, constraining the determination of floc formation rates. Furthermore, these systems typically rely on end-point measurements only. We have successfully developed for the first time a microfluidic system for the study of flocculation under well controlled conditions. In our microfluidic device (μFLOC), floc sizes and growth rates were monitored in real time using high-speed imaging and computational image analysis. The on-line and in situ detection allowed quantification of floc sizes and their growth kinetics. This eliminated the issues of sample handling, sample dispersion, and end-point measurements. We demonstrated the power of this approach by quantifying the growth rates of floc formation under forty different growth conditions by varying industrially relevant flocculating agents (pDADMAC, PEI, PEG), their concentration and dosage. Growth rates between 12.2 μm s−1 for a strongly cationic flocculant (pDADMAC) and 0.6 μm s−1 for a non-ionic flocculant (PEG) were observed, demonstrating the potential to rank flocculating conditions in a quantitative way. We have therefore created a screening tool to efficiently compare flocculating agents and rapidly find the best flocculating condition, which will significantly accelerate early bioprocess development.

Graphical abstract: Flocculation on a chip: a novel screening approach to determine floc growth rates and select flocculating agents

Supplementary files

Article information

Article type
Paper
Submitted
27 iyl 2017
Accepted
30 noy 2017
First published
18 yan 2018
This article is Open Access
Creative Commons BY license

Lab Chip, 2018,18, 585-594

Flocculation on a chip: a novel screening approach to determine floc growth rates and select flocculating agents

A. N. P. Radhakrishnan, M. P. C. Marques, M. J. Davies, B. O'Sullivan, D. G. Bracewell and N. Szita, Lab Chip, 2018, 18, 585 DOI: 10.1039/C7LC00793K

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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