Description
Lab-on-a-chip (LoC) devices are miniaturized analytical devices that integrate various functions (mixing, sorting, trapping, etc.), enabling the manipulation of cells and molecules in small volumes in a controlled environment. They cover a wide range of applications, particularly in the biomedical field, and due to the growing demand for rapid, individualized point-of-care testing, the market for miniaturized medical diagnostics is expected to reach $22.63 billions by 2029 [1]. However, most of them are currently made from petroleum-based polymers, and the increase in single-use tests will have a negative impact on the environment, both during manufacture and disposal. In the wake of growing environmental awareness, bio-based polymers have emerged as promising candidates for LoC production. Despite their potential, few studies have been published on the subject. The most widely used bio-based polymers are cellulosic materials. Fluids are transported through the device by capillarity action, and the resulting LoCs are suitable for a wide range of diagnostic applications, but not for cell manipulation. Other bio-based polymers, such as (i) zein, a by-product of ethanol production from corn, (ii) silk hydrogels, or (iii) poly(lactic acid) (PLA), have been reported, but none of them meet the specifications for LoCs in terms of micropatterning, water resistance, biocompatibility, and biodegradability [2¬]. All these preliminary results tend to indicate that this research field is promising and should be pushed further to propose a range of potential solutions. Ideally, the alternative to petroleum-based polymers for the manufacture of LoCs should be a set of complementary bio-based materials, which would enable to choose the best suited solution for each given application. Having a range of materials and technologies would also help avoiding new ecological imbalances induced by the intensive production of a single bio-based material, and whenever local production would be possible, it could also support the local economy and limit transport.
In this context, we have conducted research to develop a process for manufacturing chitosan-based lab-on-a-chip devices. Chitosan is a non-toxic, biocompatible, biodegradable and antimicrobial polysaccharide composed of D-glucosamine and N-acetyl D-glucosamine units. Obtained from the deacetylation of chitin, the second most widespread natural polymer on Earth, it is industrially produced by valorizing wastes from the seafood industry (several million tons per year). Initial research has enabled us to develop an eco-friendly protocol for thick film formation and chitosan neutralization. The water-resistance was improved by neutralization of these chitosan films in sodium hydroxide-based solutions. Hot embossing and micro-milling were evaluated for engraving channels in chitosan films, and we manufacture the first chitosan fluidic microsystems [4]. These initial results are promising, and we believe that this research will encourage the development of more environmentally friendly microfluidic devices.
[1]https://www.marketsandmarkets.com/Market-Reports/point-of-care-diagnostic-market-106829185.html
[2] Ongaro, A. E. et al. Lab a Chip 22 (17), 3122–3137. https://doi.org/10.1039/d2lc00380e
[3] Zimmer M. et al. Front. Lab. Chip. Technol. Front. Lab Chip Technol. Vol. 4:1703031, 2025. https://doi.org/10.3389/frlct.2025.1703031
[4] Zimmer M., et al., Micromachines 15, 379, 2024, https://doi.org/10.3390/mi15030379