Research On Microfluidic Electrical Impedance Tomography System For Monitoring The Locomotion Of C.elegans

Caenorhabditis elegans(C.elegans)is a commonly used multicellular model organism.Its short life cycle,ease of maintenance,diverse behavior patterns,relevance of human biology have made it an attractive model for the studies of genetics,aging,development,neurobiology and behavioral biology.As a crucial measurable item in the above research areas,locomotion of C.elegans can provide a wealth of knowledge on movement and behavior which is thus extensively used to quantify the impacts of genetic mutations and environmental factors to the worm.In recent years,microfluidic chip has been recognized as a novel and efficient experimental platform for worm research due to its good adaptation to worm size,bio-affinity,automated operation,and ability to integrate multiple detection methods.Electrical impedance sensing,which has the advantages of label-free,non-invasive and real-time monitoring,is one of the methods to be integrated.In this paper,due to the reason that only a few cases have introduced electrical impedance tomography(EIT)into the field of microfluidics,an EIT-integrated microfluidic platform is proposed for the life-span analysis of C.elegans locomotion.The main contents are as follows:(1)The proposed EIT-integrated microfluidic platform is verified by theory analysis and simulation.Finite element modeling is used to solve the EIT forward problem.A single worm monitoring unit is established in COMSOL for calculating the boundary voltages,which is used to investigate the image reconstruction algorithm suitable for worm morphological characteristics.The main factors affecting the accuracy of EIT images are explored in order to provide guidance for chip fabrication and system integration.(2)Reference to the simulation results,a microfluidic chip with microelectrode array integrated for worm culture and behavioral monitoring is designed,as well as an EIT system based on electrical impedance spectrometer is developed.The main tasks include the processing and production flow of the chip,the design of hardware circuits and the development of control software.After connecting each module,an EIT-integrated microfluidic platform is established for investigation of C.elegans locomotion.(3)Experiments of the manipulation and lifelong observation of C.elegans are carried out on the designed microfluidic chip,which realized the first step of monitoring the movement behavior of a single worm.The parameters used in this study,C.elegans activity and body curvature,are described for behavioral quantification and posture analysis.Combined with video shooting and EIT imaging,the behavior parameter curves extracted from the EIT image sequence and the original model sequence are compared and analyzed.Finally,the basic functions of the microfluidic EIT system are verified by using the resistance network and the microfluidic chip respectively.To sum up,this paper investigates C.elegans and their locomotion,and proposes an innovative worm research method combining microfluidic and electrical impedance tomography.An EIT-integrated microfluidic platform which enriches technical tools for worm research is developed through comprehensive theoretical and experimental validation.