Acoustofluidic separation technology for advancing health care
Open Access
- Author:
- Wu, Mengxi
- Graduate Program:
- Engineering Science and Mechanics
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- June 21, 2018
- Committee Members:
- Joseph Lawrence Rose, Dissertation Advisor/Co-Advisor
Joseph Lawrence Rose, Committee Chair/Co-Chair
Corina Stefania Drapaca, Committee Member
Siyang Zheng, Committee Member
Pak Kin Wong, Outside Member - Keywords:
- Microfluidics
acousitics
separation technology
biomedical engineering
nanoparticles
exosomes
circulating tumor cell
blood components
apheresis - Abstract:
- Separation of particles, cells and other biological objects is essential for down streaming analysis and a critical step in target purification in the medical field. Due to an ability to handle tiny sample amounts and to manipulate micro/nano objects precisely, microfluidic technology has served as a platform that enables a variety of separation techniques. Among the microfluidic separation techniques, acoustofluidics which is the combination of acoustics and microfluidics has great advantages in terms of label-free, contact-free, and the non-invasive aspect for biological specimens. Therefore, acoustofluidic separation technology has been widely used in biological and biomedical applications including for example blood components separation, cancer cell separation, bacteria separation, mammalian cell separation, nanoparticle separation, and extracelluar vesicle separation. Though achievements have been made, the acoustofluidic separation technology still suffers from such limitations as separation limit, separation throughput and also some other aspects. In order to fulfill the urgent demands of separation for diagnosis and therapeutics, systematic studies on acoustofluidic separation technology were performed. Significant improvements were made to upgrade the acoustofluidic separation technology. The separation of nanoscale particles is essential to the nanoscience and nanotechnology community. Acoustofluidic technology was improved such that the separation limit was expanded to nanoscale. Nanoparticles are now successfully separated in a continuous flow by using tilted‐angle standing surface acoustic waves. The acoustic field deflects nanoparticles based on volume, and the fractionation of nanoparticles is optimized by tuning the cutoff parameters. The continuous separation of nanoparticlesis was demonstrated with an approximate 90% recovery rate. The acoustofluidic nanoparticle separation method is versatile, non‐invasive, and simple. The study of circulating tumor cells (CTCs) offers pathways to the development of new diagnostic and prognostic biomarkers to benefit cancer treatments. In order to fully exploit and interpret the information provided by CTCs, rapid isolation of CTCs from blood is urgently needed. A novel acoustofluidic separation platform was developed to isolate rare CTCs from peripheral blood in high throughput while preserving their structural, biological, and functional integrity. The processing speed was improved to 7.5 mL/h, achieving a recovery rate of at least 86%, while maintaining the cells’ ability to proliferate. The high-throughput acoustofluidic separation enables statistical analysis of isolated CTCs from prostate cancer patients to determine their size distribution and phenotypic heterogeneity for a range of biomarkers, including the visualization of CTCs with a loss of expression for the prostate specific membrane antigen (PSMA). The method also enables isolation of even rarer, but clinically important, CTC clusters. Lipoproteins are abundant soluble proteins in the biological fluids, and are valuable as diagnostic biomarkers to aid in therapeutics for such diseases as atherosclerosis cardiovascular disease, coronary heart disease, heart attack, peripheral vascular disease, aortic stenosis, thrombosis and stroke. Due to their submicron size, separating lipoproteins from biological fluids is challenging. A size-independent acoustofluidic separation technique was developed that distinguishes lipoprotein subgroups based on their acoustic properties. Using this technology, subgroups of lipoproteins are separated in a label-free, contactless, and continuous manner. With the platform’s ability to perform simple, rapid, efficient, and continuous-flow isolation, the acoustic technology could become a valuable tool in health monitoring, disease diagnostics, and personalized medicine. Exosomes are nanoscale extracellular vesicles that play an important role in many biological processes, including intercellular communications, antigen presentation, and the transport of proteins, RNA, and other molecules. However, it is challenging to isolate exosomes from a biofluid such as peripheral blood. Two acoustofluidic separation modules are integrated to isolate exosomes directly from whole blood in a label-free and contact-free manner. This acoustofluidic platform consists of two modules: a microscale cell-removal module that first removes larger blood components, followed by extracellular vesicle subgroup separation in the exosome-isolation module. By integrating the two acoustofluidic modules onto a single chip, we isolate exosomes from whole blood with a blood cell removal rate of over 99.999%. With its ability to perform rapid, biocompatible, label-free, contact-free, and continuous-flow exosome isolation, the integrated acoustofluidic device offers a unique approach in the investigation of the role of exosomes in the onset and progression of human diseases with potential applications in health monitoring, medical diagnosis, targeted drug delivery, and personalized medicine. By integrating acoustofluidics and hydrodynamics, a three dimensional acoustic tweezers was developed that is able to separate cells and particles in an ultra-high throughput. I demonstrate not only the separation of 10, 12 and 15 micron particles at a throughput up to 500 µl/min, but also on the separation of erythrocytes, leukocytes and cancer cells. This method is able to meet high processing speed demands, thereby becoming a potential for clinical use. Apheresis is well established as a routine administration and treatment option for a vast number of diseases of human. However, there is no available technique that can perform apheresis for small animals due to limited blood volumes, thus inhibiting many emerging physiological and pathological studies on animal models. To resolve this issue, the first apheresis system for small animals using acoustofluidic separation techniques was developed. A prototype that consists of fluid delivery and appropriate control systems as well as blood component separation was advanced. The acoustofluidic apheresis system has demonstrated successful transfer blood cells and platelets to varied buffer fluids with an approximate 95% recovery rate. This method, as the first apheresis apparatus for small animals, fulfils the demand for a variety of fundamental studies and veterinary therapeutic applications, offers a reliable method that enables a new branch of hematology and circulation related research topics that were formerly thought to be not feasible. It has also led to pioneering studies towards product development of acoustofluidic separation technology. With the systematic optimization and many improvements, acoustofluidic separation technology offers the potential to use a series of tool sets for the applications of disease diagnosis, health monitoring, and various therapies.