The interfacial properties of solid substrates are of importance for protein adsorption. Herein, we report a reversible protein adsorption switch based on the host–guest interaction of the butoxy pillar[5]arene and adipic acid. By the detector of the contact angle (CA), atomic force microscopy (AFM), and luminoscope on the silicon substrate, the intelligent protein switch exhibits excellent adsorptivity for BSA and switch performance by pH regulation.

Design and fabrication of smart switchable nanofluidic diodes remains a challenge in the life and materials sciences. Here, we present the first example of a novel Zn²⁺/EDTA switchable nanofluidic diode system based on the control of one-side of the modified hourglass-shaped nanochannel with salicylaldehyde Schiff base (SASB). The nanofluidic diode can be turned on in the response of Zn²⁺ and turned off in response to EDTA solution with good reversibility and recyclability.

A photoreversible switch based on a photoresponsive host–guest system consisting of dimethylamino calix[4]arene L and 4-(phenylazo)benzoic acid (O) is reported. The host L exhibited selective binding and release of O on UV and visible irradiation at 450 and 365 nm, respectively. Moreover, the photoresponsive host–guest complex was applied as a photocontrolled wettability switch on a functional micro/nanostructured silicon surface, and is thus promising for applications in sensors and microfluidic devices.

Click chemistry, a new strategy for organic chemistry, has been widely used in the chemical modification of calixarenes because of its reliability, specificity, biocompatibility, and efficiency. Click-derived triazoles also play a critical role in sensing ions and molecules. This in-depth review provides an overview of calixarene-based chemosensors that incorporate click-derived triazoles, and their three characteristics (chromogenic, fluorescence, and wettability) are reviewed.

Inspired from their biological counterparts, chemical modification of the interior surface of nanochannels with functional molecules may provide a highly efficient means to control ionic or molecular transport through nanochannels. Herein, we have designed and prepared a aldehyde calix[4]arene (C4AH), which was attached to the interior surface of a single nanochannel by using a click reaction, and that showed a high response for arginine (Arg). Furthermore, the nanofluidic sensing system has been challenged with complex matrices containing a high concentration of interfering sequences and serum. Based on this finding, we believe that the artificial nanochannel can be used for practical Arg-sensing devices, and be applied in a biological environment.

A novel biomimetic ion-responsive multi-nanochannel system is constructed by covalently immobilizing a metal-chelating ligand, 2,2′-dipicolylamine (DPA), in polyporous nanochannels prepared in a polymeric membrane. The DPA-modified multi-nanochannels show specific recognition of zinc ions over other common metal ions, and the zinc-ion-chelated nanochannels can be used as secondary sensors for HPO₄²⁻ anions. The immobilized DPA molecules act as specific-receptor binding sites for zinc ions, which leads to the highly selective zinc-ion response through monitoring of ionic current signatures. The chelated zinc ions can be used as secondary recognition elements for the capture of HPO₄²⁻ anions, thereby fabricating a sensing nanodevice for HPO₄²⁻ anions. The success of the DPA immobilization and ion-responsive events is confirmed by measurement of the X-ray photoelectron spectroscopy (XPS), contact angle (CA), and current–voltage (I–V) characteristics of the systems. The proposed nanochannel sensing devices display remarkable specificity, high sensitivity, and wide dynamic range. In addition, control experiments performed in complex matrices suggest that this sensing system has great potential applications in chemical sensing, biotechnology, and many other fields.

A new aldehyde calix[4]arene (C4AH) was synthesized efficiently to give a yield of 90 % and was used to form self-assembled monolayers (SAMS) by means of click chemistry to give a highly selective wettability and impedance sensor for arginine (Arg). The success of the C4AH functional interface and Arg-responsive events were confirmed by contact-angle (CA) measurements and electrochemical impedance spectroscopy (EIS). Furthermore, the C4AH functional interface can be used as wettability-responsive cycles at least eight times. This type of sensor operates on the principle that Arg has a high pK_a value of 12.48, and is able to form strong hydrogen bonds with aldehyde selectivity, which results in a significant CA change. The proposed wettability-sensing devices display a remarkable specificity, intuitiveness, and convenience, which should be suitable for the production of arginine recognition chips that can be used in the fields of biology and medical science.

Three derivatived calix[4]crowns were condensed with calixarene segments: 2,6-bis(bromomethyl)-4-methyl-anisole (BBA) to afford their telomers TCA[4] in rational yields. The binding sites may complex metal ions or amino acids selectively. The telomers shows different metal ions selectivity in comparison with their monomers, which suggests that calixarene segment bridges play an important role in ion-binding. The liquid-liquid extraction experiment showed that telomer TCA[4]-III was excellent receptor for zwitterionic α-amino acids and soft cations Ag⁺ and Pb²⁺. The extraction percentage of tryptophan and histidine was as high as 87.9% and 91.5%, respectively.

A series of calix[10]crowns were synthesized for the first time. By reacting p-tert-butylcalix[10]arene with ethylene glycol ditosylate or polyethylene glycol ditosylates in a system of K₂CO₃/toluene or Cs₂CO₃/acetone, a series of calix[10]crowns such as 1,2-calix[10]crown-4, 1,3-calix[10]crown-2, 1,2-calix[10]crown-3, 1,3-calix[10]crown-3, 1,4-calix[10]crown-4 and 1,6-calix[10]crown-4 were obtained.