We report a new technique for sensitive, quantitative and rapid detection of Plasmodium spp.-infected red blood cells (RBCs) by means of magnetic resonance relaxometry (MRR). During the intraerythrocytic cycle, malaria parasites metabolize large amounts of cellular hemoglobin and convert it into hemozoin crystallites. We exploit the relatively large paramagnetic susceptibility of these hemozoin particles, which induce substantial changes in the transverse relaxation rate of proton nuclear magnetic resonance of RBCs, to infer the 'parasite load' in blood. Using an inexpensive benchtop 0.5-Tesla MRR system, we show that with minimal sample preparatory steps and without any chemical or immunolabeling, a parasitemia level of fewer than ten parasites per microliter in a volume below 10 μl of whole blood is detected in a few minutes. We demonstrate this method both for cultured Plasmodium falciparum parasites and in vivo with Plasmodium berghei-infected mice.

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Microwell technology has revolutionized many aspects of in vitro cellular studies from 2-dimensional (2D) traditional cultures to 3-dimensional (3D) in vivo-like functional assays. However, existing lithography-based approaches are often costly and time-consuming. This study presents a rapid, low-cost prototyping method of CO2 laser ablation of a conventional untreated culture dish to create concave microwells used for generating multicellular aggregates, which can be readily available for general laboratories. Polymethylmethacrylate (PMMA), polydimethylsiloxane (PDMS), and polystyrene (PS) microwells were investigated, and each produced distinctive microwell features. Among these three materials, PS cell culture dishes produced the optimal surface smoothness and roundness. A549 lung cancer cells were grown to form cancer aggregates of controllable size from ~40 to ~80 μm in PS microwells. Functional assays of spheroids were performed to study migration on 2D substrates and in 3D hydrogel conditions as a step towards recapitulating the dissemination of cancer cells. Preclinical anti-cancer drug screening was investigated and revealed considerable differences between 2D and 3D conditions, indicating the importance of assay type as well as the utility of the present approach.

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The 2D layered structured material with unique surface terminations and properties have showed great potential in variety of biomedical research fields including drug delivery and cancer therapeutics which forms the major focus of this review.