Sepsis is a life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. Sepsis affects 30 million people and kills more than 258,000 Americans every year. Sepsis is the most expensive condition managed in U.S. hospitals, costing the U.S. economy approximately $20 billion a year.
The research has shown that patient survival decreases by 10% for each hour of delay in receiving the correct antibiotics. However, 30–50% of patients receive inappropriate initial antibiotic therapy because physicians must treat immediately using broad-spectrum antibiotics without a precise diagnosis. The reason is that current PCR can only operate small volume thermal cycler (0.2mL), which makes delayed diagnosis. Small volume sample also leads to low sensitivity and makes harder to detect the sepsis from blood. The present gold standard, bacterial cultures coupled with antibiotic susceptibility testing cannot detect the bacteria in blood with low concentration, and requires several days.
PCRbot has designed a new and low-cost PCR machine aiming to solve this current problems by using large volume PCR thermal cycles in two water baths. Our goal is increasing PCR sample volumes (from 0.2mL to 2mL), so raises sensitivity for sepsis detection. Eventually, our product can help identify sepsis and antibiotic resistance much faster and earlier (1-2 hours), so more lives can be saved. In addition, our product is a low cost PCR device, so it can decrease the treatment cost for both hospitals and patients. For these capabilities and advantages, our product is crucial for sepsis patients and we want to save more lives.
（0.2mL current PCR cuvette)
(2mL PCRbot cuvette)
PCRbot is made up of several components such as one stepper motor which provides power to lift up the mechanical arm as well as the sample holder, an Arduino board, a solid foundation and a computer to process data. The mechanical arm is manufactured by laser cutting technology and the sample holder is made by 3D printing technology. Both technologies enable them to have high precision as well as good-looking appearance. PCRbot is able to improve the sample processing (thermal cycling) from perspectives of time period, sample volume, temperature, and number of cycles. This is a new technology that can directly detect pathogens in large volume blood specimen without enrichment or sample processing while still achieving the sensitivity, robustness and assay time that is clinically useful.
The picture above simply shows how PCRbot works. The sample holder is attached to the mechanical arm, and is rotated by a step motor between a hot water bath (95 degree Celsius) and a relative cold water bath (55 degree Celsius).
The holder contains four cuvettes of blood sample. It is originally placed in the hot water bath. After a constant time period (this is what we measured before the reaction), the mechanical arm will transfer the sample holder from the hot water bath to the other water bath. The sample holder will stay in the cold water for a constant time interval as well. Once the temperature reaches the threshold, the mechanical arm will automatically transfer the holder to the hot water bath. This is one cycle of PCR thermal cycling reaction, and the total number of cycles repetition will be around 45.
Current methods (In lab)
A thermal cycler device is currently used in lab for PCR thermal cycling reaction. There are some limitations with this method. For example, only 200-microliter cuvettes can be used by this device. Hence, it requires people to pipet the large sample into many small cuvettes. Besides, the shear force caused by pipetting may destroy some of the sample droplet, the effective volume of the sample in the cuvette is too small to conduct sensitive detection.
The mechanical arm will directly transfer the large sample holder with blood samples between two water baths. Hence, there is no need to separate the samples by pipetting and to protect the sample droplets. Meanwhile, the processed sample will increase the sensitivity for easier detection.
Advantages of PCRbot:
Large sample volume makes the detection more accurate and sensitive
The new prototype do less damage to the sample droplet
The new methods cost less than the current methods
The global in vitro diagnostics market had a value at nearly $57.3 billion in revenue in 2014. The market is expected to continue to expand with emerging medical needs, an aging population, growing trend of precision medicine (and therefore needs for better diagnostics), and increasing patient awareness.
The prototype is designed for hospitals and clinics which include microbiology labs and CLIA diagnostic laboratories. It will make tremendous change to biomedical science in developing countries like Cuba, Philippines and etc. Since PCRbot is efficient, accurate and low costing, it will enable patients in developing countries to attain affordable diagnosis as well as treatment.
Danfeng Jiang: Having a major in Materials Science Engineering, Danfeng is an expert
with a lot of past experience dealing with 3D printing. He is familiar with materials, structures
and printing methods. He is in charge of manufacturing.
Roxanne Li: Having majors in Materials Science Engineering and Quantitative
Economics, Roxanne designs detailed testing criteria and analyzes the data. With some
knowledge in economics, she takes care of business perspective.
Jie Shen: Having a major in Materials Science Engineering, Jie is responsible for
assembly since he has the strongest hands-on skills among the team. He likes thinking and
handles various technical problems in the group.
Shunwen Wang: Having a major in Biomedical Engineering, Shunwen does most of the
designing tasks. He is really familiar with Solid Work software and can quickly make different
models according to the changes in requirements.
Jiayi Zhao: Having majors in Biomedical Engineering and Economics, Jiayi is the
primary person who conducts the testing. He has lots of ideas in his mind and always provided
the team with various solutions when facing difficulties.
Dr. Weian Zhao is an Associate Professor at the Sue and Bill Gross Stem Cell Research Center, Chao Family Comprehensive Cancer Center, Department of Biomedical Engineering, Edwards Lifesciences Center for Advanced Cardiovascular Technology and Department of Pharmaceutical Sciences at University of California, Irvine. Dr. Zhao is also the co-founder of Velox Biosystems Inc, Baylx Inc, and Amberstone Biosciences LLC, start-up companies that aim to develop technologies for rapid diagnosis, stem cell therapy, and drug discovery, respectively.
Professor. Weian Zhao
Professor. Michelle Khine
Professor. William Tang