A new analytical platform for potential point-of-care testing of circulating tumor cells.

It is of significance to detect circulating tumor cells (CTCs) in whole blood using transportable instruments at the point of care to assist evaluating chemotherapeutic efficacy and recurrence risk of cancer patients. However, the current widely used detection methods either require expensive and complex equipments, need complicated enrichment steps, or produce high rates of false positive and/or negative results. Aiming for solving the two critical challenges involved in instrumentation miniaturization and simplification of sample preparation for POCT of CTCs without sacrificing the detection sensitivity and accuracy, this work reports a custom-built, automatic, large field-of-view microscopic CTC cytometer and a novel enrichment strategy based on a synthesized peptide ligand discovered from One-Bead One-Compound library screening. The custom-built microscope has compact size, low weight and efficient cost while still maintaining a detection limit of as low as 5 target objects. The simplified sample preparation utilized a novel peptide LXW7 functionalized to magnetic beads and allows for rapid, highly selective and sensitive detection of CTCs. This analytical platform may fulfill the unmet need for possible point-of-care CTC counting, and provide a new option for early diagnosis of cancers and convenient evaluation of chemotherapeutic efficacy and cancer recurrence.

A smart preparation strategy for point-of-care cellular counting of trace volumes of human blood.

Blood counting is one of the most commonly ordered clinical assays, and is often part of the basis for initial diagnosis and screening for disease. While substantial prior research has shown the ability of portable instruments to accurately produce blood counts through image- or flow-based cytometry, these methods require complex sample preparation using either costly commercial imaging chambers or complicated reagents. To address these issues, in this paper we developed a method to prepare trace volumes of whole blood aimed at portable blood counting. The strategy is based on pre-storing dry-form reagents and fabricating a specifically designed cell counter. In order to obtain total cell counts for red blood cells, platelets, and 3-part differentials of white blood cells, two parallel counting chambers with different depths are made from cost- and environmentally friendly materials using soft lithography. As little as 1 µl of whole blood is prepared with pre-stored reagents in centrifuge vials, whereas red blood cells are sphered and white blood cells are stained at the same time. Driven by the capillary force, prepared blood samples enter the hydrophilic chambers automatically. Monolayers of cells are formed when the blood dilution factors and the chamber depths are co-optimized. Combined with our previous custom-built instrument and automated analysis algorithm, the sample preparation strategy allows producing counting results with excellent agreement to a gold-standard clinical hematology instrument. The success of this preparation method may further advance applications of our technology for global use in low-resource settings where central hematology laboratories are not accessible. Graphical abstract Graphical Abstract.