Integratable non-clogging microconcentrator based on counter-flow principle for continuous enrichment of CaSki cells sample

Abstract

This study addresses the need to reduce the risk of clogging when preparing samples for cell concentration, i.e., the CaSki Cell-lines (epidermoid cervical carcinoma cells). Aiming to develop a non-clogging microconcentrator, we proposed a new counter-flow concentration unit characterized by the directions of penetrating flows being at an obtuse angle to the main flow, due to employment of streamlined turbine blade-like micropillars. Based on the optimization results of the counter-flow unit profile, a fractal arrangement for the counter-flow concentration unit was developed. A counter-flow microconcentrator chip was then designed and fabricated, with both the processing layer and collecting layer arranged in terms of the honeycomb structure. Visualized experiments using CaSki cell samples on the microconcentrator chip demonstrated that no cell-clogging phenomena occurred during the test and that no cells were found in the final filtrate. The test results show an excellent concentration performance for the microconcentrator chip, while a concentrating ratio of [4 with the flow rate being below 1.0 ml/min. As only geometrical structure is employed in the passive device, the counter-flow microconcentrator can be easily integrated into advanced microfluidic systems. Owing to the merit of non-clogging and continuous processing ability, the counter-flow microconcentrator is not only suitable for the sample preparation within biomedical field, but also applicable in water-particle separation.

A cascade-like silicon filter for improved recovery of oocysts from environmental waters

“…Detailed fabrication process is shown elsewhere. [21] For the packaging device, connecting channels for the concentrate and filtrate were arranged in a polycarbonate substrate. Screwed holes as the inlet and outlet ports of the MPR device were arranged in the substrate for connecting external tubing.…”

“…[21,22] The new filtration principle is performed by a silicon-microfabricated concentrator chip, where the particles are retained within the circulating water sample through sieving. The concentrator mainly comprises two filtration layers: one is the active layer for the concentrate or retentate and the other is the collection layer for the filtrate.…”

Recovery ofCryptosporidiumandGiardiaorganisms from surface water by counter-flow refining microfiltration

“…A detailed description of the μC device can be found elsewhere. [26] Briefly, it mainly comprises two filtration layers, the active layer with counter-flow recovery (CFR) cells, and the collection layer (see Figure 1(a)). Continuous-flow concentration of water particles is performed by the active layer.…”

“…[26] The active and collection layer were arranged in two 4-inch (100 mm) silicon wafers that were incorporated together by silicon-Au-silicon thermal bonding. For sealing, a Pyrex 7740 glass wafer was added to the aforementioned layers by anodic bonding.…”

Increasing the protozoan recovery for biomedical membrane filters using multiplexed refining device

“…Each refining unit comprises a microconcentrator chip (see Fig 1b), in where the active layer comprises multiple counter-flow recovery cells (CFR). The CFR cells form micro-sized gaps between adjacent turbine blade-like micro-pillars, as described in [7]. Thanks to silicon microfabrication technology, the dimension of those gaps can be varied.…”