Real-time detection of phosphate has significant meaning in marine environmental monitoring and forecasting the occurrence of harmful algal blooms. Conventional monitoring instruments are dependent on artificial sampling and laboratory analysis. They have various shortcomings for real-time applications because of the large equipment size and high production cost, with low target selectivity and the requirement of time-consuming procedures to obtain the detection results. We propose an optofluidic miniaturized analysis chip combined with micro-resonators to achieve real-time phosphate detection. The quantitative water-soluble components are controlled by the flow rate of the phosphate solution, chromogenic agent A (ascorbic acid solution) and chromogenic agent B (12% ammonium molybdate solution, 80% concentrated sulfuric acid and 8% antimony potassium tartrate solution with a volume ratio of 80 : 18 : 2). Subsequently, an on-chip Fabry–Pérot microcavity is formed with a pair of aligned coated fiber facets. With the help of optical feedback, the absorption of phosphate can be enhanced, which can avoid the disadvantages of the macroscale absorption cells in traditional instruments. It can also overcome the difficulties of traditional instruments in terms of size, parallel processing of numerous samples and real-time monitoring, etc. The absorption cell length is shortened to 300 μm with a detection limit of 0.1 μmol L⁻¹. The time required for detection is shortened from 20 min to 6 seconds. Predictably, microsensors based on optofluidic technology will have potential in the field of marine environmental monitoring.

Food production in green crops is severely limited by low activity and poor specificity of D-ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) in natural photosynthesis (NPS). This work presents a scientific solution to overcome this problem by immobilizing RuBisCO into a microfluidic reactor, which demonstrates a continuous production of glucose precursor at 13.8 μmol g⁻¹ RuBisCO min⁻¹ from CO₂ and ribulose-1,5-bisphosphate. Experiments show that the RuBisCO immobilization significantly enhances enzyme stabilities (7.2 folds in storage stability, 6.7 folds in thermal stability), and also improves the reusability (90.4% activity retained after 5 cycles of reuse and 78.5% after 10 cycles). This work mimics the NPS pathway with scalable microreactors for continuous synthesis of glucose precursor using very small amount of RuBisCO. Although still far from industrial production, this work demonstrates artificial synthesis of basic food materials by replicating the light-independent reactions of NPS, which may hold the key to food crisis relief and future space colonization.

Multicellular aggregates in three-dimensional (3D) environments provide novel solid tumor models that can provide insight into in vivo drug resistance. Such models are therefore essential for developing new drugs and preventing the failure of clinical treatments. However, high-throughput cell cluster assembly and fabricating individual 3D environments that mimic the extracellular matrix (ECM) remain significant challenges. To rapidly produce mini 3D multicellular aggregate units, acoustic force assembly combined with ECM mimic hydrogel array encapsulation is developed and then integrated into a diffusion-based microfluidic device for high-throughput drug testing. The active acoustic force gathers human mononuclear leukemia cells (THP-1) into hundreds of multicellular clusters with a controllable size. Instead of continuous bulk materials, photosensitive gelatin methacryloyl (GelMA) hydrogel pillar arrays containing cell clusters at drug concentration gradients are obtained through selective area exposure. Ten azelaic acid (AZA) concentration gradient series are applied to 100 units to simultaneously test the multicellular cluster drug resistance to multiple drug conditions. Real-time green fluorescent protein (GFP) fluorescence is analyzed to monitor cell viability. The results show that cell aggregate activity is inversely related to the drug concentration in the hydrogel pillars, and shows lower sensitivity to drug toxicity than the activity of monolayer cultured cells. The 3D multicellular arrays provide numerous in vitro tumor models and can be directly used for downstream drug testing. This technology inherits the advantages of acoustic assembly, while being more flexible, practical, and high-throughput, and shows significant potential for use in further tumor related research and clinical practice.

Precise and non-invasive circulating tumor cell isolation based on optical force using homologous erythrocyte binding in a microfluidic system.

The increase in the levels of reactive oxygen species (ROS) in acute myeloid leukemia (AML) patients has been previously described; thus, it is important to regulate ROS levels in AML. Flow cytometry were used to assess the in vitro effect of compound kushen injection (CKI). Quantitative proteomics were used to analyse the mechanism. The AML patient-derived xenograft (PDX) model were used to evaluate the in vivo effect of CKI. We found that intracellular ROS levels in AML cells were decreased, the antioxidant capacity were increased when treated with CKI. CKI inhibited the proliferation of AML cells and enhanced the cytotoxicity of AML cells, which has few toxic effects on haematopoietic stem cells (HSCs) and T cells. At the single-cell level, individual AML cells died gradually by CKI treatment on optofluidic chips. CKI promoted apoptosis and arrested cell cycle at G1/G0 phase in U937 cells. Furthermore, higher peroxiredoxin-3 (Prdx3) expression levels were identified in CKI-treated U937 cells through quantitative proteomics detection. Mechanically, the expression of Prdx3 and peroxiredoxin-2 (Prdx2) was up-regulated in CKI-treated AML cells, while thioredoxin 1 (Trx1) was reduced. Laser confocal microscopy showed that the proteins Prdx2 could be Interacted with Trx1 by CKI treatment. In vivo, the survival was longer and the disease was partially alleviated by decreased CD45+ immunophenotyping in peripheral blood in the CKI-treated group in the AML PDX model. Antioxidant CKI possess better clinical application against AML through the Prdxs/ROS/Trx1 signalling pathway.