Accurate prediction of drug-induced heterogeneous response of red cell in vivo using a gravity-driven flow cytometry based on a microfluidic chip.

The drug-induced diverse response among patients is a severe problem for improving hemorheological character. However, there is no validated method for personalized therapy to the best of our knowledge. Here, we apply a gravity-driven deformability cytometry platform (GD-DCP) to profile the drug response of the red cell deformability (RCD) at the single-cell level using pentoxifylline (PTX) as a model drug, the effect of different concentrations of PTX (0, 2, 20, 200 µg mL-1, the clinical dosage of PTX is 20 µg mL-1) on RCD in patients with cardiovascular disease was explored. Based on the GD-DCP, about 38 and 56% of the acute phase of acute myocardial infarction (AMI) patients in the acute phase and coronary heart disease (CHD) patients respond positively to PTX, respectively, indicating that PTX has a strong patient dependency on RCD. Moreover, RCD is observed to be significantly inversely correlated with the activation of membrane protein kinase C (PKC) as well as the concentration of Ca2+ (both P < 0.001). The results of animal experiments show that the protective effects of PTX on myocardial ischemia rats have substantial individual variation, too. It is noted that the effect of PTX is highly consistent between RCD in vitro and in vivo outcomes (blood viscosity, myocardial injury, and electrocardiogram (ECG)) in the same rat. All these new findings suggest that the GD-DCP is a promising method that uses deformability in vitro as one of the important criteria in personalized medicine, and our study provides unique insight into the individual-dependent mechanisms of PTX for improving RCD.

Slanted spiral microfluidics for the ultra-fast, label-free isolation of circulating tumor cells.

The enumeration and characterization of circulating tumor cells (CTCs), found in the peripheral blood of cancer patients, provide a potentially accessible source for cancer diagnosis and prognosis. This work reports on a novel spiral microfluidic device with a trapezoidal cross-section for ultra-fast, label-free enrichment of CTCs from clinically relevant blood volumes. The technique utilizes the inherent Dean vortex flows present in curvilinear microchannels under continuous flow, along with inertial lift forces which focus larger CTCs against the inner wall. Using a trapezoidal cross-section as opposed to a traditional rectangular cross-section, the position of the Dean vortex core can be altered to achieve separation. Smaller hematologic components are trapped in the Dean vortices skewed towards the outer channel walls and eventually removed at the outer outlet, while the larger CTCs equilibrate near the inner channel wall and are collected from the inner outlet. By using a single spiral microchannel with one inlet and two outlets, we have successfully isolated and recovered more than 80% of the tested cancer cell line cells (MCF-7, T24 and MDA-MB-231) spiked in 7.5 mL of blood within 8 min with extremely high purity (400-680 WBCs mL(-1); ~4 log depletion of WBCs). Putative CTCs were detected and isolated from 100% of the patient samples (n = 10) with advanced stage metastatic breast and lung cancer using standard biomarkers (CK, CD45 and DAPI) with the frequencies ranging from 3-125 CTCs mL(-1). We expect this simple and elegant approach can surmount the shortcomings of traditional affinity-based CTC isolation techniques as well as enable fundamental studies on CTCs to guide treatment and enhance patient care.