Per- and poly-fluoroalkyl substances (PFASs) are man-made chemicals that are toxic and widely detected in the environment, including drinking water sources. A cost-effective treatment process for PFASs is currently not available. We developed reusable hydrogel sorbents to remove long- and short-chain perfluoroalkyl acids and 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoic acid (GenX), which is are emerging PFAS. Through fluoridation and amination of poly(ethylene glycol) diacrylate (PEGDA), the newly synthesized sorbents can sorb the five targeted PFASs (perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorobutanesulfonic acid (PFBS), and perfluorobutanoic acid (PFBA) and GenX) to different degrees from aqueous solution. Aminated PEGDA showed the highest sorption capacity for all five PFASs, particularly for PFBA and PFBS. The bifunctionalized PEGDA showed higher capacities for PFOA and PFOS, suggesting that both hydrophobic interactions and charges contribute to the sorption. Both aminated and bifunctionalized sorbents can remove GenX from water, with the highest sorption capacity of 98.7 μmol g aminated PEGDA^–1 within 6 h. The absorbed PFASs on the sorbents were observed and characterized by Fourier-transform infrared spectroscopy. The spent sorbents were reusable after readily regenerated with 70% methanol contained 1% NaCl.

We have developed an integrated microfluidic material processing chip and demonstrated the rapid production of collagen microspheres encapsulating cells with high uniformity and cell viability. The chip integrated three material processing steps. Monodisperse microdroplets were generated at a microfluidic T junction between aqueous and mineral oil flows. The flow was heated immediately to 37 °C to initiate collagen fiber assembly within a gelation channel. Gelled microspheres were extracted from the mineral oil phase into cell culture media within an extraction chamber. Collagen gelation immediately after microdroplet generation significantly reduced coalescence among microdroplets that led to non-uniform microsphere production. The microfluidic extraction approach led to higher microsphere recovery and cell viability than when a conventional centrifugation extraction approach was employed. These results indicate that chip-based material processing is a promising approach for cell-ECM microenvironment generation for applications such as tissue engineering and stem cell delivery.

For the hundreds of millions of worldwide diabetic patients, glucose test strips are the most important and commonly used tool for monitoring blood glucose levels. Commercial test strips use glucose oxidases as recognition agents, which increases the cost and reduces the durability of test strips. To lower the cost of glucose sensors, we developed a paper-based electrical sensor with molecularly imprinted glucose recognition sites and demonstrated the determination of various glucose concentrations in bovine blood solutions. The sensing electrode is integrated with molecular recognition sites in the conductive polymer. A calibration graph as a function of glucose concentration in aqueous solution was acquired and matched with a correlation coefficient of 0.989. We also demonstrated the determination of the added glucose concentrations ranging from 2.2 to 11.1 mM in bovine blood samples with a linear correlation coefficient of 0.984. This non-enzymatic glucose sensor has the potential to reduce the health care cost of test strips as well as make glucose sensor test strips more accessible to underserved communities.

Extracellular vesicles (EVs) play an important role in intercellular communication. Recently, there has been increasing interest in EVs as potential diagnostic biomarkers and therapeutic vehicles. However, the molecular properties and cargo information of EV subpopulations have not yet been fully investigated due to lack of reliable and reproducible EV separation technology. Current approaches have faced difficulties with efficiently isolating EVs from biofluids, especially subpopulations of small EVs. Here, we report an EV isolation method based on a size-selective microfluidic platform (ExoSMP) via nanomembrane filtration and electrophoretic force. This unique platform offers an enhanced approach to sorting a heterogeneous population of EVs based on size, with the additional advantages of being label-free and low-cost, and featuring a short processing time (<1 h), and convenient integration with downstream analysis. In this research, we used ExoSMP to demonstrate the isolation of cancer-derived small EVs (30–120 nm) with high recovery (94.2%) and reproducibility at an optimum sample flow rate. Furthermore, we investigated isolation of EV subpopulations by altering nanomembrane combinations with different pore size combinations (50 and 100 nm, 30 and 100 nm, 30 and 200 nm, and 30 and 50 nm). This ExoSMP technique can serve as a standardized EV isolation/separation tool, facilitating the clinical prospects of EVs and opening up a new avenue for future point-of-care applications in liquid biopsies.