Moving from Microfluidics to Millifluidics for Liposome Production

Liposomes are tiny vesicles of lipid layers enclosing medication for drug delivery, mostly used in cancer treatment and gene therapy. The applications of the technique are widespread and continuously growing since major advantages such as targeted delivery of medication and high rate of efficiency inspire scientific research into medical applications. However, some challenges associated to the production of liposomes require more in-depth research in this area. One of the production technologies implies the use of microfluidic mixers which produce liposomes at a very low yield. Previous research proved the viability of liposomes production but at a very low yield. Based on the successful results of the liposome production at micro-scale, the assumption that scaling up the channel size may lead to production of liposomes as well was made. Hence, simulations of the mixing of two fluids within scaled up channels using same ratio of mixing were carried out. The objective is to produce nanosized vesicles using channels of larger cross-sections and hence, increased yield of liposomes. Same flow parameters and mixing ratio were considered in simulations. However, from the mathematical model, the resulting size of the liposomes cannot be predicted. It may be possible that along with larger channels, larger liposomes to be produced. To prevent this issue, the same fluid properties will be used during the mixing of a solution containing lipids and alcohol with water, which will result in liposomes formation. The hypothesis behind this experiment states that the size of the liposome depends on the speed of mixing, which is bounded by fluid flow properties, such as velocity, pressure and concentration, that will need to remain similar in values in the enlarged microfluidic device. During simulation, similar mixing results were obtained as the base research, which indicate good mixing efficiency when scaling up the cross-section area by 10 and 25 times. Computing power was limited and inconclusive simulation results were reached when trying to increase the cross section by 100 times. It seems that it may be possible to increase production of liposomes through larger devices if the pressure inside the channels is increased due to the higher flow rate which is also scaled by a factor corresponding to the dimension increase. A larger production rate could be a game changer in the pharma industry.