The lack of an efficient method for the identification of tumor antigen-specific T cell receptors (TCRs) impedes the development of T cell-based cancer immunotherapies. Here, we introduce a droplet-based microfluidic platform for function-based screening and sorting of tumor antigen-specific T cells with high throughput. We built a reporter cell line by co-transducing the TCR library and reporter genes at the downstream of TCR signaling, and reporter cells fluoresced upon functionally binding with antigens. We co-encapsulated reporter cells and antigen-presenting cells in droplets to allow for stimulation on a single-cell level. Functioning reporter cells specific against the antigen were identified in the microfluidic channel based on the fluorescent signals of the droplets, which were immediately sorted out using dielectrophoresis. We validated the reporter system and sorting results using flow cytometry. We then performed single-cell RNA sequencing on the sorted cells to further validate this platform and demonstrate the compatibility with genetic characterizations. Our platform provides a means for precise and efficient T cell immunotherapy, and the droplet-based high-throughput TCR screening method could potentially facilitate immunotherapeutic screening and promote T cell-based anti-tumor therapies.

A mesoporous carbon confined PdCu bimetallic electrocatalyst is fabricated, which delivers a superior nitrate conversion yield and nitrogen selectivity.

For redox-active hematite (α-Fe2O3) materials, the adverse electroconductivity deeply obstructs the electrocatalytic activity. Herein, a series of iron oxides including α-Fe2O3 nanoplates, α-Fe2O3/Fe3O4 composites, and Fe3O4 material was prepared via a controllable reduction treatment on α-Fe2O3 precursor. When these iron oxides were characterized as electrocatalysts for oxygen reduction reaction (ORR), it was found that α-Fe2O3 nanoplates could be effectively activated via the reduction treatment. In particular, as the combined merits of composition optimization and electroconductivity improvement, the as-reduced composite consisting of α-Fe2O3 (49.6%) and Fe3O4 (50.4%) achieved the best activity of reaching the current density of 4.90 mA cm–2 at the potential of 0.4 V versus reversible hydrogen electrode (RHE) accompanied by a Tafel slope of 76 mV dec–1 and a high selectivity for four-electron pathway, surpassing single-phase α-Fe2O3 and Fe3O4, as well as other congeneric iron oxide composites. This high performance may offer a great potential of developing electrocatalysts with optimized composition and physicochemical properties.

A subtle catalyst design is provided with stably incorporated binary catalytically active centers of CuO and MnO2 on the surface wall of mesoporous TiO2. Such unique features render these mesoporous composites highly promising in the low-temperature selective catalytic reduction of NO with NH3, including high NO conversion efficiency, and superior H2O and SO2 resistance.

We report a new sensor for the specific detection of lead ions (Pb 2+) in contaminated water based on fluorescence resonance energy transfer (FRET) between upconversion nanoparticles (UCNPs) as donors and gold nanoparticles (Au NPs) as receptors. The UCNPs modified with Pb 2+ aptamers could bind to Au NPs, which were functionalized with complementary DNA through hybridization. The green fluorescence of UCNPs was quenched to a maximum rate of 80% due to the close proximity between the energy donor and the acceptor. In the presence of Pb 2+ , the FRET process was broken because Pb 2+ induced the formation of G-quadruplexes from aptamers, resulting in unwound DNA duplexes and separated acceptors from donors. The fluorescence of UCNPs was restored, and the relative intensity had a significant linear correlation with Pb 2+ concentration from 0 to 50 nM. The sensor had a detection limit as low as 4.1 nM in a buffer solution. More importantly, the sensor exhibited specific detection of Pb 2+ in complex metal ions, demonstrating high selectivity in practical application. The developed FRET prober may open up a new insight into the specific detection of environmental pollution.

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