Using Reflectometric Interference Spectroscopy to Real-Time Monitor Amphiphile-Induced Orientational Responses of Liquid-Crystal-Loaded Silica Colloidal Crystal Films

Abstract

An approach to optical transduction and amplification of amphiphile-triggered orientational responses of liquid crystals (LCs) based on the interference effect was developed. The sensitive substrate was obtained by lading 4′-pentyl-4-cyanobiphenyl (5CB) into three-dimensionally ordered silica colloidal crystal (SCC) films. Changes in the optical thickness (ΔOT) of the substrates, which are inverted by their Fabry–Perot fringes, depend on the changes of the refractive index caused by the differences in the orientations of LCs. The orientation changes of LCs loading into SCC films have the effect of amplifying signals. These are based on the interactions between surfactants (alkyl trimethylammonium halides (CnTABs, n = 8, 10, 12, 14, and 16) and sodium lauryl sulfonate (SLS)) and LCs, which induce a particular orientation of the LCs molecules. In this flowing system, the reversibility of the signal response for the adsorption of amphiphile was related to the length of the surfactant chain and its critical micelle concentration (CMC). A new method capable of real-time sensing adsorbate-triggered anchoring transitions based on LC-infiltrated SCC films was accomplished. These results provide basics and principles for online, label-free, and real-time analysis of molecules and their interactions in a flowing environment based on the interference effect.

Ordered Porous Layer Interferometry for Dynamic Observation of Non-Specific Adsorption Induced by 1-Ethyl-3-(3-(dimethylamino)propyl) Carbodiimide

“…The thickness of the SCC film was approximately 2.74 μm (Figure C), and the typical interference fringes (Figure D) allow multipeak fitting to improve the reliability of interferometry results . The OPLI has shown enough possibilities for monitoring the digestive process of gelatin by trypsin, biomolecular interactions within complex biological media, amphiphile-induced orientational responses, and the thrombolytic process of drugs in our previous reports. ,,, …”

“…51 The OPLI has shown enough possibilities for monitoring the digestive process of gelatin by trypsin, biomolecular interactions within complex biological media, amphiphile-induced orientational responses, and the thrombolytic process of drugs in our previous reports. 43,50,52,53 Here, we hypothesize that the sole EDC-induced adducting causes potential NSA; adding sulfo-NHS can minimize the NSA by reaction path tuning. Briefly, we conjugated CTC onto BSA with EDC chemistry to produce CTC−BSA.…”

Real-time monitoring of the hydrolysis of vegetable oils loaded in silica colloidal crystal films with lipase by optical interferometry

“…The preparation of the SCC films was the same as in a previous work. 34 First, the silica microsphere suspensions were repeatedly centrifuged with ultrapure water and anhydrous ethanol, the purpose of which was to wash off the salt ions in the stock solution. Second, the silica microspheres with a particle size of about 190 nm were separated and the mass fraction of the silica microsphere suspension was recorded.…”

“…The SCC films loaded with vegetable oil were prepared in the manner described previously. 34 First, the SCC films were treated with piranha solution and then OTS for alkylation. Second, the SCC films were covered with glass slides and then 1 ∼ 2 drops of vegetable oil were added at the seams.…”

Real-Time Monitoring of Curcumin Release with a Lipid–Curcumin-Loaded Silica Colloidal Crystal Film Using Optical Interferometry

“…Silica alcohol and an OTS-coated SCC film were prepared and processed in the same way. , First, the vertical deposition method was used to grow an SCC film on the surface of the glass slide. The entire film growth progress was carried out on a vibration-free bench in a temperature-controlled laboratory (25 ± 0.5 °C) and the relative humidity was <10%.…”