Research

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Point -of-care immune health profiling in T2DM

Dysfunction of circulating immune cells including neutrophils and monocytes are strongly linked to type 2 diabetes mellitus (T2DM) pathophysiology and atherosclerosis development, but their prognostic potential as biomarkers remains largely unexplored due to arduous leukocyte isolation methods. Our group has recently engineered a novel neutrophil purification microdevice based on Dean Flow Fractionation (DFF)1-3 for rapid immune health profiling in T2DM patients using a drop of blood4 (highlighted in The Straits Times, Mediacorp Channel 8, News Medical.net, ScienceDaily). We have also developed an integrated neutrophil sorting and phenotyping (chemotaxis, NETosis) microfluidic device based on biomimetic blood margination5, and successfully demonstrated its clinical utilities in risk stratification of T2DM patients, as well as study of neutrophil responses with in vitro metformin treatment6. These studies have clearly illustrated the potential use of microfluidics technologies for immune health profiling in T2DM, and we are currently integrating biosensing capabilities to these microfluidics platforms for translational diabetes research and large scale clinical cohort studies.

DFF

References

    1. H.W. Hou, M.E. Warkiani, B.L. Khoo, Z.R. Li, R.A. Soo, D.S.W. Tan, W.T. Lim, J. Han, A.A.S. Bhagat and C.T. Lim, Isolation and retrieval of circulating tumor cells using centrifugal forces. Scientific Reports, 3, 2013.
    2. H.W. Hou, R.P. Bhattacharyya, D.T. Hung and J. Han, Direct detection and drug-resistance profiling of bacteremias using inertial microfluidics. Lab on a Chip, 15(10): p. 2297-2307, 2015.
    3. D.Yeo, C. Wiraja, Y.Y. Zhou, H.M. Tay, C.J. Xu* and H.W. Hou*, Interference-free micro/nano-particle cell engineering using high-throughput microfluidic separation. ACS Applied Materials & Interfaces, 7(37): p. 20855-20864, 2015.
    4. H.W. Hou, C. Petchakup, H.M. Tay, Z.Y. Tam, R. Dalan, D.E.K. Chew, K.H.H. Li and B.O. Boehm, Rapid and label-free microfluidic neutrophil purification and phenotyping in diabetes mellitus. Scientific Reports, 6, 2016.
    5. H.W. Hou, A.A.S. Bhagat, A.G.L. Chong, P. Mao, K.S.W. Tan, J. Han and C. T. Lim, Deformability based cell margination – A simple microfluidic design for malaria infected erythrocyte separation. Lab on a Chip, 10(19): p. 2605-2613, 2010.
    6. H.M. Tay, R. Dalan, K.H.H. Li, B.O. Boehm* and H.W. Hou*, An integrated microdevice for neutrophil functional phenotyping in diabetes testing, Small, 1702832-n/a, 2018.

Microfluidics microvesicles isolation and phenotyping

T2DM predisposes patients to various vascular complications affecting the heart (cardiovascular), kidneys (nephropathy), nerves (neuropathy) and eyes (retinopathy). Circulating microvesicles (MVs) are small (~50 nm -1 µm) membrane-bound fragments actively shed into bloodstream by exocytotic budding from activated/apoptotic endothelium, platelets and leukocytes. They carry associated membrane proteins and lipids of cellular origin, as well as biologically active intracellular cargo. MVs are key mediators for intercellular communication and pathophysiological responses in T2DM, and are widely proposed as surrogate biomarkers for diabetes testing. We have recently developed a novel spiral MVs sorter, aptly termed as High-resolution Dean Flow Fractionation (HiDFF), to isolate sub-micron circulating MVs from whole blood directly1. HiDFF-purified MVs exhibited well-preserved surface morphology, and we also observed strong associations of immune cell-derived MVs with cardiovascular risk factors (BMI, CIMT and triglyceride). Current efforts are focused on developing this technology into a clinical tool for rapid quantitative MVs-based assessment of immune and vascular health.

HiDFF

References

  1. H.M. Tay, S. Kharel, R. Dalan, Z.J. Chen, K.K. Tan, B.O. Boehm, S.C.J. Loo and H.W. Hou*, Rapid purification of sub-micrometer particles for enhanced drug release and microvesicles isolation. NPG Asia Materials, 9: e434, 2017.

Biomimetic microengineered human organ-on-chip platforms

Organ-on-chip platforms are exciting technological tools to study human organ functions and responses at the cellular level. To better understand the pathophysiological impact of immune and vascular dysfunction in metabolic disorders, we are developing biomimetic cell-based microdevices to model atherosclerosis, the leading cause of CVDs. As atherosclerosis is a geometrical-focal disease, our recent work primarily focus on investigating the effects of biophysical cues (blood flow) and vascular geometries1, and leukocyte-endothelial interactions2 in atherosclerosis. By serving as surrogate disease models to study host pathophysiological responses in vivo, these biomimetic platforms can significantly advance translational biomedical research in prognostics and diagnostics of CVDs, understanding disease etiology and organ physiology, and development of novel therapeutic interventions. The developed organ-on-chip technologies can also be engineered for study of other major disease burden (cancer, infectious diseases) and toxicity testing (pharmacokinetics /pharmacodynamics).

organ on chip

References

  1. N.V. Menon, H.M. Tay, S.N. Wee, K.H.H. Li and H.W. Hou*, Micro-engineered perfusable 3D vasculature for cardiovascular diseases. Lab on a Chip, 17(17): p. 2960-2968, 2017.
  2. N.V. Menon, H.M. Tay, K.T. Pang, R. Dalan, S.C. Wong, X.M. Wang, K.H.H. Li and H.W. Hou*, A tunable microfluidic 3D stenosis model to study leukocyte-endothelial interactions in atherosclerosis, APL Bioengineering, 2(1): 016103, 2018. (in press)

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