Peng Sun

Bio: Peng Sun is an academic researcher from Northwest A&F University. The author has contributed to research in topics: Cell & Cell type. The author has an hindex of 4, co-authored 4 publications receiving 200 citations. Previous affiliations of Peng Sun include Laboratory of Molecular Biology.

Atomic force microscope study of tumor cell membranes following treatment with anti-cancer drugs

Abstract: Integrity of the cell membrane is a basic requirement for maintaining the biological characteristics of a cell. In this study, changes in the morphology and ultrastructure of HeLa (human cervical carcinoma), HepG2 (human hepatocellular liver carcinoma), and C6 (rat glioma) cells were studied by atomic force microscopy (AFM) both before and after treatment with the anti-cancer drugs, colchicine or cytarabine. In response to both drugs, the microstructure of the cell membrane of all three cell types displayed similar changes; that is, with increases in drug concentration and reaction time, the degree of morphological changes on the surface of cell membrane increased. These changes included increases in the fluctuation of the surface components of the cell membrane, increase in shrinkage, or even the appearance of pores. Cell viability was maintained, as determined by optical microscope observation of gross cell morphology and by MTT assay results. Analysis of the cell membrane root-mean-square (RMS) roughness showed that under the action of colchicine and cytarabine, RMS values for the cell membranes of all three tumor cell types were positively correlated to the drug concentration and reaction time. This research has great significance for the visual diagnosis of early stage apoptosis in tumor cells in response to anti-cancer drugs, as well as in the studies on the interaction between drugs and cells. The use of AFM can be a rapid and sensitive visual method for studying the interaction between cells and drug.

High-throughput microfluidic system for long-term bacterial colony monitoring and antibiotic testing in zero-flow environments.

Abstract: In this study, a high-throughput microfluidic system is presented. The system is comprised of seven parallel channels. Each channel contains 32 square-shaped microchambers. After simulation studies on samples loaded into the microchambers, and the solute exchange between the microchambers and channels, the long-term culture of Escherichia coli (E. coli) HB101 in the microchambers is realized. Using the principle that l -arabinose ( l -Ara) can induce recombinant E. coli HB101 pGLO to synthesize green fluorescent protein (GFP), the real-time analysis of GFP expression in different initial bacterial densities is performed. The results demonstrate that higher initial loading densities of the bacterial colony cause bacterial cell to enter log-phase proliferation sooner. High or low initial loading densities of the bacterial cell suspension induce the same maximum growth rates during the log-phase. Quantitative on-chip analysis of tetracycline and erythromycin inhibition on bacterial cell growth is also conducted. Bacterial morphology changes during antibiotic treatment are observed. The results show that tetracycline and erythromycin exhibit different inhibition activities in E. coli cells. Concentrations of 3 μg/mL tetracycline can facilitate the formation of long filamentous bacteria with the average length of more than 50 μm. This study provides an on-chip framework for bacteriological research in a high-throughput manner and the development of recombinant bacteria-based biosensors for the detection of specific substances.

Conjugation of biomolecules with magnetic protein microspheres for the assay of early biomarkers associated with acute myocardial infarction.

Abstract: This study demonstrates an improved magnetic protein microsphere-aided sandwich fluoroimmunoassay for the analysis of myoglobin and heart-type fatty acid binding protein (H-FABP), early protein markers associated with acute myocardial infarction. In preparation for the assay we constructed superparamagnetic human serum albumin (HSA)/γ-Fe2O3 microspheres, and grafted capture antibodies (monoclonal antimyoglobin 7C3 and anti-H-FABP 10E1) onto the protein microspheres using the avidin−biotin system. Then the antibody-carrying microspheres were used in a sequential sandwich fluoroimmunoassay along with detection antibodies (Alexa fluor594-labeled antimyoglobin 4E2 and FITC-labeled anti-H-FABP 9F3). The magnetic HSA/γ-Fe2O3 microspheres were characterized by scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectrophotometry, atomic absorption spectrophotometry, and vibrating sample magnetometry. Fluorescence images of the post-immunoassay microspheres recorded using an inverted...

Assay of glioma cell responses to an anticancer drug in a cell-based microfluidic device

Abstract: Despite progress in research and treatment, the prognosis for patients with gliomas remains relatively dismal. As such, develop a new in vitro model is fast becoming a necessary step in efforts to improve research on malignant gliomas. Microfluidics, a potentially effective tool, has been increasingly applied in neuroscience and oncology studies. However, gliomas, the most common primary brain tumours, have not yet been treated with this application. In the current study, we developed a glioma-related research method using microfluidics. After successfully culturing rat C6 glioma cells for up to 7 days in a microfluidic device, we monitored cellular responses to the anticancer drug, colchicines, after which we analysed cell viability using propidium iodide (PI) staining. We recorded temporal changes in cell morphology at various concentrations of colchicine using an inverted microscope. Results show that the number of injured/dead cancer cells and morphological changes increased relative to the drug’s concentration and treatment frequency. These findings will be helpful in developing microfluidic device applications for future research on brain tumour therapy (for malignant gliomas and other types of tumours), for conducting cytotoxicity research in a biomimetic microenvironment, for developing glioma-related anticancer drugs, and for developing glial cell-based biosensors for glioma detection.

Advances in microfluidic materials, functions, integration, and applications.

Abstract: Microfluidics consist of microfabricated structures for liquid handling, with cross-sections in the 1–500 μm range, and small volume capacity (fL-nL) Capillary tubes connected with fittings,1 although utilizing small volumes, are not considered microfluidics for the purposes of this paper since they are not microfabricated Likewise, millifluidic systems, made by conventional machining tools, are excluded due to their larger feature sizes (>500 μm) Though micromachined systems for gas chromatography were introduced in the 1970’s,2 the field of microfluidics did not gain much traction until the 1990’s3 Silicon and glass were the original materials used, but then the focus shifted to include polymer substrates, and in particular, polydimethylsiloxane (PDMS) Since then the field has grown to encompass a wide variety of materials and applications The successful demonstration of electrophoresis and electroosmotic pumping in a microfluidic device provided a nonmechanical method for both fluid control and separation4 Laser induced fluorescence (LIF) enabled sensitive detection of fluorophores or fluorescently labeled molecules The expanded availability of low-cost printing allowed for cheaper and quicker mask fabrication for use in soft lithography5 Commercial microfluidic systems are now available from Abbott, Agilent, Caliper, Dolomite, Micralyne, Microfluidic Chip Shop, Micrux Technologies and Waters, as a few prominent examples For a more thorough description of the history of microfluidics, we refer the reader to a number of comprehensive, specialized reviews,3, 6–11 as well as a more general 2006 review12 The field of microfluidics offers many advantages compared to carrying out processes through bulk solution chemistry, the first of which relates to a lesson taught to every first-year chemistry student Simply stated, diffusion is slow! Thus, the smaller the distance required for interaction, the faster it will be Smaller channel dimensions also lead to smaller sample volumes (fL-nL), which can reduce the amount of sample or reagents required for testing and analysis Reduced dimensions can also lead to portable devices to enable on-site testing (provided the associated hardware is similarly portable) Finally, integration of multiple processes (like labeling, purification, separation and detection) in a microfluidic device can be highly enabling for many applications Microelectromechanical systems (MEMS) contain integrated electrical and mechanical parts that create a sensor or system Applications of MEMS are ubiquitous, including automobiles, phones, video games and medical and biological sensors13 Micro-total analysis systems, also known as labs-on-a-chip, are the chemical analogue of MEMS, as integrated microfluidic devices that are capable of automating multiple processes relevant to laboratory sciences For example, a typical lab-on-a-chip system might selectively purify a complex mixture (through filtering, antibody capture, etc), then separate target components and detect them Microfluidic devices consist of a core of common components Areas defined by empty space, such as reservoirs (wells), chambers and microchannels, are central to microfluidic systems Positive features, created by areas of solid material, add increased functionality to a chip and can consist of membranes, monoliths, pneumatic controls, beams and pillars Given the ubiquitous nature of negative components, and microchannels in particular, we focus here on a few of their properties Microfluidic channels have small overall volumes, laminar flow and a large surface-to-volume ratio Dimensions of a typical separation channel in microchip electrophoresis (μCE) are: 50 μm width, 15 μm height and 5 cm length for a volume of 375 nL Flow in these devices is normally nonturbulent due to low Reynolds numbers For example, water flowing at 20°C in the above channel at 1 μL/min (222 cm/s) results in a Reynolds number of ~05, where <2000 is laminar flow Since flow is nonturbulent, mixing is normally diffusion-limited Small channel sizes also have a high surface-to-volume ratio, leading to different characteristics from what are commonly found in bulk volumes The material surface can be used to manipulate fluid movement (such as by electroosmotic flow, EOF) and surface interactions For a solution in contact with a charged surface, a double layer of charge is created as oppositely charged ions are attracted to the surface charges This electrical double layer consists of an inner rigid or Stern Layer and an outer diffuse layer An electrostatic potential known as the zeta potential is formed, with the magnitude of the potential decreasing as distance from the surface increases The electrical double layer is the basis for EOF, wherein an applied voltage causes the loosely bound diffuse layer to move towards an electrode, dragging the bulk solution along Charges on the exposed surface also exert a greater influence on the fluid in a channel as its size decreases Larger surface-to-volume ratios are more prone to nonspecific adsorption and surface fouling In particular, non-charged and hydrophobic microdevice surfaces can cause proteins in solution to denature and stick We focus our review on advances in microfluidic systems since 2008 In doing this, we occasionally must cover foundational work in microfluidics that is considerably less recent We do not focus on chemical synthesis applications of microfluidics although it is an expanding area, nor do we delve into lithography, device fabrication or production costs Our specific emphasis herein is on four areas within microfluidics: properties and applications of commonly used materials, basic functions, integration, and selected applications For each of these four topics we provide a concluding section on opportunities for future development, and at the end of this review, we offer general conclusions and prospective for future work in the field Due to the considerable scope of the field of microfluidics, we limit our discussion to selected examples from each area, but cite in-depth reviews for the reader to turn to for further information about specific topics We also refer the reader to recent comprehensive reviews on advances in lab-on-a-chip systems by Arora et al10 and Kovarik et al14

Single-cell analysis of circulating tumor cells identifies cumulative expression patterns of EMT-related genes in metastatic prostate cancer.

Abstract: BACKGROUND. Prostate tumors shed circulating tumor cells (CTCs) into the blood stream. Increased evidence shows that CTCs are often present in metastatic prostate cancer and can be alternative sources for disease profiling and prognostication. Here we postulate that CTCs expressing genes related to epithelial–mesenchymal transition (EMT) are strong predictors of metastatic prostate cancer. METHODS. A microfiltration system was used to trap CTCs from peripheral blood based on size selection of large epithelial-like cells without CD45 leukocyte marker. These cells individually retrieved with a micromanipulator device were assessed for cell membrane physical properties using atomic force microscopy. Additionally, 38 CTCs from eight prostate cancer patients were used to determine expression profiles of 84 EMT-related and reference genes using a microfluidics-based PCR system. RESULTS. Increased cell elasticity and membrane smoothness were found in CTCs compared to noncancerous cells, highlighting their potential invasiveness and mobility in the

Recent Development of Sandwich Assay Based on the Nanobiotechnologies for Proteins, Nucleic Acids, Small Molecules, and Ions

Abstract: Nanobiotechnologies for Proteins, Nucleic Acids, Small Molecules, and Ions Juwen Shen, Yuebin Li,†,§,⊥ Haoshuang Gu, Fan Xia,*,† and Xiaolei Zuo*,‡ †Key Laboratory for Large-Format Battery Materials and System, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China ‡Division of Physical Biology and Bioimaging Center, Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Science, Shanghai 201800, China Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Faculty of Physical and Electronic Sciences, Hubei University, Wuhan 430062, China Key Laboratory of Systems Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China

Microfluidics for Manipulating Cells

Abstract: Microfluidics, a toolbox comprising methods for precise manipulation of fluids at small length scales (micrometers to millimeters), has become useful for manipulating cells. Its uses range from dynamic management of cellular interactions to high-throughput screening of cells, and to precise analysis of chemical contents in single cells. Microfluidics demonstrates a completely new perspective and an excellent practical way to manipulate cells for solving various needs in biology and medicine. This review introduces and comments on recent achievements and challenges of using microfluidics to manipulate and analyze cells. It is believed that microfluidics will assume an even greater role in the mechanistic understanding of cell biology and, eventually, in clinical applications.

Microfluidics Expanding the Frontiers of Microbial Ecology

Abstract: Microfluidics has significantly contributed to the expansion of the frontiers of microbial ecology over the past decade by allowing researchers to observe the behaviors of microbes in highly controlled microenvironments, across scales from a single cell to mixed communities. Spatially and temporally varying distributions of organisms and chemical cues that mimic natural microbial habitats can now be established by exploiting physics at the micrometer scale and by incorporating structures with specific geometries and materials. In this article, we review applications of microfluidics that have resulted in insightful discoveries on fundamental aspects of microbial life, ranging from growth and sensing to cell-cell interactions and population dynamics. We anticipate that this flexible multidisciplinary technology will continue to facilitate discoveries regarding the ecology of microorganisms and help uncover strategies to control microbial processes such as biofilm formation and antibiotic resistance.