Inertial Microfluidics For Separation Of Bacteria From Blood

With the diagnosis and treatment of sepsis,traditional methods based on blood culture typically require at least 24 hours,and there is a problem with genetic amplification by PCR in the presence of blood components.The rapid separation of bacteria from blood would help to the genetic identification by PCR or other methods,so that the appropriate antibiotic regimen can be quickly selected for the sepsis patient.Among the newly emerging pathogenic separation techniques,the inertial microfluidic technology has got many attention because of their significant advantages,such as simple channel structure,no auxiliary field,convenient manipulation and high-throughput processing.Herein,the purpose of this article is to explore the separation device and optimize the channel structure and operating conditions based on inertial microfluidic manipulation mechanism,then character the separation performance of the device from different aspects,such as different dilutions,multiple sorting,different pathogenic species.Finally,we develop an extremely high through-put separation device based on UV laser direct writing and roll-to-roll lamination process,and then verify the separation effect.The main work is summarized as follows:(1)Research the critical controllable factors of the inertial microfluidic device.According to the regulation mechanism of inertial micro fluidic technology,the spiral structure is chosen and was optimized from the operation flow,the channel sectional ratio and the length.The controllable velocity range is obtained by summing up the phenomena of particle inertial migration during the whole velocity segment.The width of the channel is chosen by comparing the inertial focusing effect of the particles in different section dimension.Then,the length of spiral channel is determined from two aspects of theoretical calculation and experiment.Finally,the effect of the blood dilution multiple on the migration of blood cells is studied so as to obtain the optimal dilution of blood cells.(2)Study The separation performance of the spiral inertial microfluidic devices used for separation bacteria from blood from several aspects.The separation performance is characterized by two major parameters:the blood removal rate and the bacterial recovery rate.The results show the performance can be improved by raising the dilution ratio.Using a two-stage spiral flow channel microfluidic can slightly improve the separation performance.Finally,the effects of different types bacteria are investigated.The results show that the separation efficiency is not related to the bacteria species.Above all,the inertial separation device can remove 98%blood cell and recover 62%bacteria.(3)Fabricate the high-throughput integrated device based on the exploration of multilayer polymer chip process and verify the separation performance of the device:Firstly,the process parameters of UV laser direct writing about this structure height and thermal lamination are explored.Then an integrated device is developed to apply the polymer chip and the sealing performance and separation performance of the device is tested.Then a multi-channel parallel polymer chip and the corresponding fixture is developed,the separation effect of the high-throughput device was verified.By comparing with the existing several bacteria isolation technologies,our device behaves superior especially in the sample throughput.