Tushar Harishchandra Punde

Fibrocyte trafficking in patients with chronic obstructive asthma and during an acute asthma exacerbation.

BACKGROUND Fibrocytes express several chemokine receptors (CCR7 and CXCR4) that regulate their recruitment and trafficking into tissue-damage sites in response to specific chemokine gradients (CCL19 and CXCL12). OBJECTIVE We investigated whether these chemoattractants and S100A9, through the receptor for advanced glycation end-products (RAGE; ie, its receptor), are involved in fibrocyte trafficking in patients with chronic obstructive asthma (COA) and during an acute exacerbation (AE) in patients without airflow obstruction (Asthma AE group). METHODS We collected peripheral blood from 14 asthmatic patients with normal pulmonary function, 14 patients with COA, 11 patients in the Asthma AE group, and 14 healthy subjects. Isolated circulating fibrocytes were used for migration assay. Expression of CCR7, CXCR4, S100A9, and RAGE in fibrocytes was measured by using flow cytometry. CCL19 and CXCL12 expression in bronchial tissues was determined by using immunohistochemistry and RT-PCR. RESULTS There were higher numbers of circulating fibrocytes in patients in the Asthma AE group and patients with COA. The expression of CXCL12 in bronchial tissues and CXCR4 in circulating fibrocytes was higher in the Asthma AE group and, to a lesser extent, in patients with COA. The expression of CCL19 in bronchial tissues and CCR7 in fibrocytes was higher in patients with COA. CXCL12/CXCR4 and CCL19/CCR7 enhanced fibrocyte transmigration in the Asthma AE group and in patients with COA, respectively. The upregulated expression of S100A9 and RAGE in fibrocytes of patients in the Asthma AE group and those with COA contributes to the enhanced basal migratory motility of fibrocytes. CONCLUSION The CXCR4/CXCL12 axis contributes to chemotaxis of fibrocytes in patients in the Asthma AE group, whereas the CCR7/CCL19 axis plays an important role in patients with COA. S100A9 enhances the basal migratory motility of fibrocytes from patients in the Asthma AE group and patients with COA.

Precise cell trapping with structure-confined dielectrophoresis

We present a precise cell trapping platform, structure-confined electrophoresis, which utilize microchannel with lateral cavity to bend the electric field for generating positive dielectrophoresis (DEP) force. A revealed metal electrode, 10µm × 20µm, is placed inside the deep place of cavity. Providing stronger DEP force to trap mobile cells and reducing the flow shear stress acting on the trapped cell are two advantages of the cavity design. The cells trapping efficiency are increased by the multi-channel design. Five microchannels provide 400 cells trapping locations. Finally, we calibrate the relationship between flow velocity, applied ac voltage and the trapped cells number. This application utilizing structure to confine the electric field distribution is not only to provide the accurate cells trapping function, but to be a platform for electrical fusion approach of trapped cells.

A miniaturized optically-induced fluorescence-activated cell sorter

We integrate the concept of liquid light-driven approach and a cell fluorescent detection system to sort different labeled color HepG2 and 3T3 cells. The optoelectroosmosis flow (OEOF) method would drive the liquid and reverse the flow direction immediately only with light pattern movement. A dielectrophoresis (DEP) force is applied to focal the moving cells as a line. A LabVIEW program would detect the fluorescent cell color and switch the projected light pattern automatically to manipulate the mobile cell real-time. After the OEOF operation, the selected cell is able to push a lateral displacement with 120µm distance against original direction. Based on these four features, this article demonstrates a potential for cells sorting with light driving approaches.

An integrated lobule-mimetic liver chip for testing hepatotoxicity

The current trend in personalized healthcare shows that medical care is becoming as individualized as possible. The goal is not only to provide customized diagnostic tests but also to target medicines and dosages more precisely and safely to each patient. Here in this article we report an integrated drug testing device based on lobule-mimetic liver pattern for testing in vitro drug toxicity. We aimed at achieving customized diagnostic tests by reconstructing and mimicking a liver pattern in vitro for predicting the in vivo drug hepatotoxicity.

Lung cancer model on chip for drug testing

In this paper we have simulated an in vitro lung cancer microenvironment by dielectrophoresis (DEP) patterning. Heterogeneous cells were patterned on the glass substrate, above which a microfluidic gradient is integrated to generate different concentration of target therapy drug (Iressa). Taking advantage of DEP pattern and microfluidic gradient, we designed a biochip to mimic the in vivo conditions. The influence of drug treatment for cell patterning is better than the non-patterned case as visualized in cell viability rate by MTT assay.

In Vitro Reconstruction of Tumor Microenvironment for Studying Angiogenesis

Angiogenesis is an important mechanism in organ growth and development, oxygen supply, reproduction, wound healing and also in cancer progression. Anti-angiogenic therapy is a topic of interest for cancer cure by inhibiting cancer progression. In this research, we have developed a microfluidic device which integrates a gradient generator and DEP cell patterning technology to reconstruct the micro environment around tumor for the studying angiogenesis and drug screening.

Optical-driven vortex as a microparticle concentator

The light-driven optoelectronic vortex concept is firstly reported in this article. Utilizing illuminating light image to manipulate the liquid flow direction without any mechanic components is the feature of this design, named as optoelectroosmosis flow (OEOF). With the simple spin-coating process to form a thin organic photoconductive material, TiOPc, on the designed ITO pattern, the projected light pattern is able to generate dynamic virtual electrode on the substrate surface. Besides, the non-uniform electric field distribution would drive the ions moving with slip velocity. Furthermore, two light driven flows with different directions are able to form a clockwise or counter clockwise for microparticles concentration from non-illuminating toward illuminating region. This convenient approach of light-driven flow and microparticle concentration without any mechanical component enlarge the scope of liquid manipulation field.

A 3-D capillary-endothelium-mimetic microfluidic chip for studying the extravasation behaviour of neutrophils

Inflammation is a fundamental biology problem with daily threats to human health. In early inflammatory stage, the most important cell type involved is neutrophil, which represents the most massive leukocyte population. In this paper, we report a 3D reusable microfluidic chip which mimics the capillary endothelial lining and we have made an attempt to imitate the hemodynamic-factor in order to study the extravasation behavior of neutrophils. This microsystem is a continuous flow system which mimics the dynamic, three dimensional micro environment in the blood vessel.