Designing N-coordinated porous single-atom catalysts (SACs) for the oxygen reduction reaction (ORR) is a promising approach to achieve enhanced energy conversion due to maximized atom utilization and higher activity. Here, we report two Co(II)-porphyrin/ [2,1,3]-benzothiadiazole (BTD)-based covalent organic frameworks (COFs; Co@ rhm -PorBTD and Co@ sql -PorBTD), which are efficient SAC systems for O2 electrocatalysis (ORR). Experimental results demonstrate that these two COFs outperform the mass activity (at 0.85 V) of commercial Pt/C (20%) by 5.8 times (Co@ rhm -PorBTD) and 1.3 times (Co@ sql -PorBTD), respectively. The specific activities of Co@ rhm -PorBTD and Co@ sql -PorBTD were found to be 10 times and 2.5 times larger than that of Pt/C, respectively. These COFs also exhibit larger power density and recycling stability in Zn–air batteries compared with a Pt/C-based air cathode. A theoretical analysis demonstrates that the combination of Co-porphyrin with two different BTD ligands affords two crystalline porous electrocatalysts having different d-band center positions, which leads to reactivity differences toward alkaline ORR. The strategy, design, and electrochemical performance of these two COFs offer a pyrolysis-free bottom-up approach that avoids the creation of random atomic sites, significant metal aggregation, or unpredictable structural features.

Solid porous and crystalline covalent organic frameworks (COFs) are characterized by their higher specific BET surface area and functional pore walls which allow the adsorption of various bioactives inside the...

Construction of a vitamin E-based liposomal biomaterial and its ability to deliver therapeutic genes selectively across liver cancer cells are demonstrated herein. In humans, liver regulates the levels of α-tocopherol, i.e., vitamin E, and hepatic cells carry the machinery for its transport. To exploit the presence of tocopherol transport protein, we have selected an efficient gene transfecting α-tocopherol-based twin lipid bearing a hydroxyethylated headgroup and octamethylene spacer (TH8S) for liposome formation. Also, based on the abundancy of the low-density lipoprotein receptor (LDLr) on the cellular surface in the case of hepatocellular carcinoma, anti-LDLr monoclonal antibody is used to confer the targeting ability to liposomes. A facile thiol–maleimide click chemistry is used for antibody decoration on the liposomal surface. Selective delivery of reporter and therapeutic genes (GFP and p53) to cells of hepatic origin was observed using anti-LDLr-tagged TH8S liposomes. Cellular internalization by receptor-mediated endocytosis renders the bioconjugate highly specific as well as highly efficient. Compatibility of the designed material with human blood points to its safety of use in systemic circulation thereby highlighting its in vivo potential. Thus, we report here a versatile biomaterial derived from an essential vitamin that promises potential for targeted suicidal gene therapy.

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A simple, easy to synthesize, cost‐effective fluorescent turn‐on sensor is developed for the selective detection of human serum albumin (HSA) in both biological and environmental samples. The biosensor is unique with qualities of rapidly quantifying HSA levels both at lower and higher concentrations in divergent bio‐fluids with high sensitivity. This probe has also been successfully used for the quantitative determination of serum albumin levels in a large number of patients’ samples having different clinical manifestations. Electrochemical detection of HSA concentrations can also be achieved with this biosensor using a potentiostat. Thus, this probe offers a unique potential of diagnosing HSA levels directly from patient samples using its bimodal (i.e., photophysical and electrochemical) properties, which are hitherto unknown to date.