Advances in miniaturized instruments for genomics

A Review on Microdevices for Isolating Circulating Tumor Cells

Cancer metastasis is the primary cause of high mortality of cancer patients. Enumeration of circulating tumor cells (CTCs) in the bloodstream is a very important indicator to estimate the therapeutic outcome in various metastatic cancers. The aim of this article is to review recent developments on the CTC isolation technologies in microdevices. Based on the categories of biochemical and biophysical isolation approaches, a literature review and in-depth discussion will be included to provide an overview of this challenging topic. The current excellent developments suggest promising CTC isolation methods in order to establish a precise indicator of the therapeutic outcome of cancer patients.

Synthetic biology for bioengineering virus-like particle vaccines

Vaccination is the most effective method of disease prevention and control. Many viruses and bacteria that once caused catastrophic pandemics (e.g., smallpox, poliomyelitis, measles, and diphtheria) are either eradicated or effectively controlled through routine vaccination programs. Nonetheless, vaccine manufacturing remains incredibly challenging. Viruses exhibiting high antigenic diversity and high mutation rates cannot be fairly contested using traditional vaccine production methods and complexities surrounding the manufacturing processes, which impose significant limitations. Virus-like particles (VLPs) are recombinantly produced viral structures that exhibit immunoprotective traits of native viruses but are noninfectious. Several VLPs that compositionally match a given natural virus have been developed and licensed as vaccines. Expansively, a plethora of studies now confirms that VLPs can be designed to safely present heterologous antigens from a variety of pathogens unrelated to the chosen carrier VLPs. Owing to this design versatility, VLPs offer technological opportunities to modernize vaccine supply and disease response through rational bioengineering. These opportunities are greatly enhanced with the application of synthetic biology, the redesign and construction of novel biological entities. This review outlines how synthetic biology is currently applied to engineer VLP functions and manufacturing process. Current and developing technologies for the identification of novel target-specific antigens and their usefulness for rational engineering of VLP functions (e.g., presentation of structurally diverse antigens, enhanced antigen immunogenicity, and improved vaccine stability) are described. When applied to manufacturing processes, synthetic biology approaches can also overcome specific challenges in VLP vaccine production. Finally, we address several challenges and benefits associated with the translation of VLP vaccine development into the industry.

Investigation of Growth Factor and Tenocyte Proliferation Induced by Platelet Rich Plasma (PRP) in a 3-Chamber Co-Culture Device

The platelet-rich plasma (PRP) has become an attractive topic for soft tissue healing therapy recently. While some clinical reports revealed the effective treatments for knee osteoarthritis, lateral epicondylitis, and rotator cuff tears, other case studies showed that there was no statistically significant healing improvement. The efficacy of the PRP therapy is still unclear clinically. Thus, a significant amount of basic studies should be conducted to optimize the preparation procedure and the platelet concentration of the PRP. In this work, a 3-chamber co-culture device was developed for the PRP study in order to reduce the usage of primary cells and to avoid the PRP gelation effect. The device was a culture, well partitioning into 3 sub-chambers. Tenocytes and PRP could be respectively loaded into the sub-chambers and co-cultured under the interlinked medium. The results showed that a higher platelet number in the PRP could diffuse higher concentration of the growth factors in the medium and induce higher tenocyte proliferation. The 3-chamber co-culture device provides a simple and practical tool for the PRP study. It is potentially applied for optimizing the preparation procedure and platelet concentration of the PRP therapy.

Quantitative Study of Cell Invasion Process under Extracellular Stimulation of Cytokine in a Microfluidic Device

Cell invasion is the first step of cancer metastasis that is the primary cause of death for cancer patients and defined as cell movement through extracellular matrix (ECM). Investigation of the correlation between cell invasive and extracellular stimulation is critical for the inhabitation of metastatic dissemination. Conventional cell invasion assay is based on Boyden chamber assay, which has a number of limitations. In this work, a microfluidic device incorporating with impedance measurement technique was developed for quantitative investigation of cell invasion process. The device consisted of 2 reservoirs connecting with a microchannel filled with hydrogel. Malignant cells invaded along the microchannel and impedance measurement was concurrently conducted by measuring across electrodes located at the bottom of the microchannel. Therefore, cell invasion process could be monitored in real-time and non-invasive manner. Also, cell invasion rate was then calculated to study the correlation between cell invasion and extracellular stimulation, i.e., IL-6 cytokine. Results showed that cell invasion rate was directly proportional to the IL-6 concentration. The microfluidic device provides a reliable and convenient platform for cell-based assays to facilitate more quantitative assessments in cancer research.

Impedimetric quantification of cells encapsulated in hydrogel cultured in a paper-based microchamber

Recently, 3D cell culture technique was proposed to provide a more physiologically-meaningful environment for cell-based assays. With the development of microfluidics technology, cellular response can be quantified by impedance measurement technique in a real-time and non-invasive manner. However, handling of these microfluidic systems requires a trained engineering personnel and the operation is not compatible to traditional biological research laboratories. In this work, we incorporated the impedance measurement technique to paper-based 3D cell culture model and demonstrated non-invasive quantification of cells encapsulated in hydrogel during the culture course. A cellulose filter paper was patterned with an array of circular microchambers. Cells were encapsulated in hydrogel and loaded to the microchambers for culturing cells in 3D environment. At the preset schedule during the culture course, the paper was placed on a glass substrate with measurement electrodes for the impedance measurement. Cells in each microchamber was represented by impedance magnitude and cell proliferation could be studied over time. Also, conventional bio-assay was performed to further confirm the feasibility of the impedimetric quantification of cells encapsulated in hydrogel cultured in the paper-based microchamber. This technique provides a convenient, fast, and non-invasive approach to monitor cells cultured in 3D environment. It has potential to be developed for routine 3D cell culture protocol in biological research laboratories.