Microwell technology has revolutionized many aspects of in vitro cellular studies from 2D traditional cultures to 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 are investigated, and each produces distinctive microwell features. Among these three materials, PS cell culture dishes produce the optimal surface smoothness and roundness. A549 lung cancer cells are grown to form cancer aggregates of controllable size from ≈40 to ≈80 μm in PS microwells. Functional assays of spheroids are 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 is investigated and reveals considerable differences between 2D and 3D conditions, indicating the importance of assay type as well as the utility of the present approach.

Despite significant advancements over the years, there remains an urgent need for low cost diagnostic approaches that allow for rapid, reliable and sensitive detection of malaria parasites in clinical samples. Our previous work has shown that magnetic resonance relaxometry (MRR) is a potentially highly sensitive tool for malaria diagnosis. A key challenge for making MRR based malaria diagnostics suitable for clinical testing is the fact that MRR baseline fluctuation exists between individuals, making it difficult to detect low level parasitemia. To overcome this problem, it is important to establish the MRR baseline of each individual while having the ability to reliably determine any changes that are caused by the infection of malaria parasite. Here we show that an approach that combines the use of microfluidic cell enrichment with a saponin lysis before MRR detection can overcome these challenges and provide the basis for a highly sensitive and reliable diagnostic approach of malaria parasites. Importantly, as little as 0.0005% of ring stage parasites can be detected reliably, making this ideally suited for the detection of malaria parasites in peripheral blood obtained from patients. The approaches used here are envisaged to provide a new malaria diagnosis solution in the near future.

The electrochemical behavior of iron ion in haemoglobin provides insight to the chemical activity in the red blood cell which is important in the field of hematology. Herein, the detection of haemoglobin in human red blood cells on glassy carbon electrode (GC) was demonstrated. Red blood cells or raw blood cells was immobilized on a glassy carbon electrode surface with Nafion films employed to sandwich the layer of biological sample firmly on the electrode surface. Cyclic voltammetry (CV) analyses revealed a well-defined reduction peak for haemoglobin at about −0.30 V (vs. Ag/AgCl) at the red blood cell (GC-Nf-RBC-3Nf) and blood (GC-Nf-B-3Nf) film modified GCE in a pH 3.5 phosphate buffer solution. We further demonstrated that the complex biological conditions of a human red blood cell displayed no interference with the detection of haemoglobin. Such findings shall have an implication on the possibilities of studying the electrochemical behaviour of haemoglobin directly from human blood, for various scientific and clinical purposes.

This paper reports the fabrication and characterization of an adhesive-based liquid-metal microcoil for magnetic resonance relaxometry (MRR). Conventionally, microcoils are fabricated by various techniques such as electroplating, microcontact printing and focused ion beam milling. These techniques require considerable fabrication efforts and incur high cost. In this paper, we demonstrate a novel technique to fabricate three-dimensional multilayer liquid-metal microcoils together with the microfluidic network by lamination of dry adhesive sheets. One of the unique features of the adhesive-based technique is that the detachable sample chamber can be disposed after each experiment and the microcoil can be reused without cross-contamination multiple times. The integrated microcoil has a low direct-current (DC) resistance of 0.3 Ω and a relatively high inductance of 67.5 nH leading to a high quality factor of approximately 30 at 21.65 MHz. The microcoil was characterized for ∼0.5 T proton MRR measurements. The optimal pulse duration, amplitude, and frequency for the 90° pulse were 131 μs, −30 dB (1.56 W) and 21.6553 MHz, respectively. In addition, we used the liquid-metal microcoil to perform a parametric study on the transverse relaxation rate of human red blood cells at different hematocrit levels. The transverse relaxation rate increases quadratically with the hematocrit level. The results from the liquid-metal microcoil were verified by measurements with a conventional solenoid coil.