Highly Sensitive Glass Nanopipette Sensor Using Composite Probes of DNA-Functionalized Metal–Organic Frameworks

Abstract

Pore structure-based analytical techniques have great potential applications for the detection of biological molecules. However, the sophistication of traditional pore sensors is restricted in their applicability of analytical chemistry due to a lack of effective carrier probes. Here, we used porous coordination network-224 (PCN-224) composite probes in conjunction with a glass nanopipette (GN) as a sensing platform. The sensor exhibits a good fluorescence signal and a change in GN’s ionic current at the same time. Due to the volume exclusion mechanism coming from PCN-224, the detection limit of target DNA reaches 10 fM in a GN with a diameter of up to ca. 260 nm, outperforming a simple probe. The structure of the composite probe is optimized by the probe’s pairing efficiency. Furthermore, the sensor can also discriminate between 1-, 3-, and 5-mismatch DNA sequences and capture the target DNA from a complex mixture. Based on the GN platform, a series of techniques for detecting biomolecules are expected to emerge because of its simplicity, robustness, and universality by incorporating advanced nanoprobes.

Ion-Selective Micropipette Sensor for In Vivo Monitoring of Sodium Ion with Crown Ether-Encapsulated Metal–Organic Framework Subnanopores

“…Furthermore, the porosity and pore-size distribution of 18-crown-6@ZIF-8 were analyzed using N 2 adsorption–desorption isotherms. Figure E shows an obvious decrease in N 2 uptake of 18-crown-6@ZIF-8 compared to that of bulk ZIF-8, with the Brunauer–Emmett–Teller (BET) surface area decreasing from 1168.5 to 867.4 m 2 g –1 due to the cavity occupation by 18-crown-6 in the frameworks. ,− Correspondingly, the calculated pore size of 18-crown-6@ZIF-8 was much smaller compared with that of ZIF-8. TGA also confirmed that the 18-crown-6 molecules were embedded in the ZIF-8 cavities during the growth process (Figure S2).…”

“…To fabricate a nanofluidic sensor with selective ion sensing property, 18-crown-6@ZIF-8 was synthesized in situ within a micropipette tip by using an interfacial growth strategy. − The aperture of the micropipette was about 2.5 μm, as shown in Figure A, and was fully filled with the composites. The functional ISMS exhibits high selectivity toward Na + transport, as evidenced by the typical current–voltage ( I – V ) curves recorded in various solutions, including NaCl, KCl, CaCl 2 , and MgCl 2 (Figure B).…”

A DNA-Schiff base functional nanopore sensing platform for the highly sensitive detection of Al3+and Zn2+ions

“…Similar to the work of Liu, 33 we made a slight improvement for the modification of capture DNA on the inner surface of GN: the TESP-SA (1% v/v in isopropanol) solution was backfilled into the GN to react with the silicon hydroxyl groups on the interior surface for 1 h at room temperature. The GN was thoroughly rinsed with ethanol several times and dried at 60 °C in a vacuum oven for 1.5 h. The aqueous solutions of 200 mM EDC and 50 mM NHSS were filled into the GN and kept for 8 h to form NHSS ester in the GN.…”

Sensitive Current Sensor Based on a Lanthanide Framework with Lewis Basic Bipyridyl Sites for Cu2+ Detection

“…In this context, when MOFs do not have fluorescence properties, ion detection will not be possible. However, some recent work in detection revealed that, when a chemical reaction occurs within the nanopores of MOFs, the current through the holes will change significantly, and this variation of current can also be employed for the detection of ions. − Moreover, using this method, Liu and co-workers successfully constructed an artificial sodium ion-selective ionic device with a selectivity ratio of Na + /K + up to 15 via growing a crown ether crystal in situ in the tip of the glass micropipette . This study opens the door for the construction of a variety of artificial ion channels with adjustable selectivity for metal ions.…”