Easy-to-perform and cost-effective fabrication of continuous-flow reactors and their application for nanomaterials synthesis

Abstract

The translation of continuous-flow microreactor technology to the industrial environment has been limited by cost and complexity of the fabrication procedures and the requirement for specialised infrastructure. In the present study, we have developed a significantly more cost-effective and easy-to-perform fabrication method for the generation of optically transparent, continuous-flow reactors. The method combines 3D printing of master moulds with sealing of the PDMS channels' replica using a pressure-sensitive adhesive tape. Morphological characterisation of the 3D printed moulds was performed and reactors were fabricated with an approximately square-shaped cross-section of 1 mm. Notably, they were tested for operation over a wide range of volumetric flow rates, up to 20 ml/min. Moreover, the fabrication time (i.e., from design to the finished product) was <1 day, at an average material cost of ∼£5. The flow reactors have been applied to the production of both inorganic nanoparticles (silver nanospheres) and organic vesicular systems (liposomes), and their performance compared with reactors produced using more laborious fabrication methods. Numerical simulations were performed to characterise the transport of fluids and chemical species within the devices. The developed fabrication method is suitable for scaled-up fabrication of continuous-flow reactors, with potential for application in biotechnology and nanomedicine.

Continuous Production of Silver Nanoparticles and Process Control

“…The maximum absorbance depends on the shape, particle size, aggregation level, etc. [17]. For the nanosilver-tannic acid system, control charts were prepared for each process using data collected from the UV-Vis analysis in the wavelength range 404-416 nm.…”

“…To demonstrate the usability of the technique, reactors were applied to the production of silver nanoparticles and liposomes. The advantage of the work was the development of a cost-effective and easy-to-perform fabrication method for continuous flow reactors production [17].…”

Synthesis of Biomaterials Utilizing Microfluidic Technology

“…Most importantly, liposomes with multiple compartments could be prepared using this method ( Figure 2 ci,cii), a process inaccessible to conventional methods. Subsequently, vesosomes, a special subset of liposomes encapsulating multilayered liposomal structures, were fabricated using the same system [ 44 ] ( Figure 2 ciii). The number of liposomes within a vesosome could be directly controlled through adjustment of volumetric flow rate.…”

“…Especially, the research of Deshpande et al [ 42 ]. and Deng et al [ 43 , 44 ]. demonstrated that GUVs without residual oil in the bilayer could be continuously fabricated through double-emulsion microfluidics techniques.…”

“… Droplet emulsion-based method used to fabricate liposomes. ( a ) Schematic of a microfluidic double emulsion process; ( b ) an octanol-assisted liposome assembly (OLA) in a microfluidic device; ( c ) liposomes with various structures prepared by microfluidic double emulsions; ( i , ii ) multicompartment liposomes with uniform ( i ) or distinct components ( ii ) (reprinted with permission from [ 43 ] Copyright (2016) American Chemical Society); ( iii ) vesosomes with different number of liposomes in their core (reprinted with permission from [ 44 ] Copyright (2017) American Chemical Society); ( d ) thermal dynamics of the membrane-less organelle-like compartment in liposomes (reprinted with permission from [ 45 ]); and ( e ) schematic process for incorporating biomolecules into droplet-stabilized giant unilamellar vesicles (dsGUVs) through pico-injection droplet microfluidic technology, scale bar: 50 μm (reprinted with permission from [ 46 ]). …”