A low-cost liquid crystal display (LCD)-printed microfluidic device: fabrication and application in the biodegradation of petroleum hydrocarbons in petroleum refinery sludge

Abstract

Liquid crystal display (LCD) printing is evolving into a ground-breaking technique in the biological domain, demonstrating the benefits of fabricating low-cost, high-resolution, complex geometry in bulk compared to the time-consuming and labour-intensive lithography techniques. However, the exploration of 3D-printed microfluidic devices for bioremediation and biofilm formation remains underrepresented in the current literature. This article describes the validation of a cost-effective LCD-printed microfluidic device that was employed as a biofilm-assisted carrier for the remediation of petroleum hydrocarbons in refinery sludge. Our technology surpasses current bioremediation approaches by providing a degrading surface that differs from standard methods relying solely on particulate carriers. A novel microbial consortium comprising four hydrocarbon-degrading strains (Dietzia sp. IRB191, Dietzia sp. IRB192, Staphylococcus sp. BSM19, and Stenotrophomonas sp. IRB19), isolated from refinery sludge, was enforced to form a biofilm on the microchannel's surface. The microfluidic device was fabricated by optimizing the printing layer height, curing timelight intensity and post-processing techniques. Micro-CT scanning was performed to analyse the deviation in the overall dimensions of the microchannels. Microscopy suggested an increase in extracellular polymeric substance (EPS) accumulation and roughness value with the increase in incubation time. The roughness value increased from 93 nm to 162 nm after a duration of 15 days. The microfluidic device exhibited a tensile strength of 18.57 MPa, which shows the structural stability of the fabricated device. Approximately 82% ± 6% of total hydrocarbons from the petroleum refinery waste were degraded during a period of 15 days, as confirmed by gravimetric analysis and gas chromatography-mass spectrometry (GC-MS) measurements.