From Self-Assembly of Colloidal Crystals toward Ordered Porous Layer Interferometry

Abstract

Interferometry-based, reflectometric, label-free biosensors have made significant progress in the analysis of molecular interactions after years of development. The design of interference substrates is a key research topic for these biosensors, and many studies have focused on porous films prepared by top-down methods such as porous silicon and anodic aluminum oxide. Lately, more research has been conducted on ordered porous layer interferometry (OPLI), which uses ordered porous colloidal crystal films as interference substrates. These films are made using self-assembly techniques, which is the bottom-up approach. They also offer several advantages for biosensing applications, such as budget cost, adjustable porosity, and high structural consistency. This review will briefly explain the fundamental components of self-assembled materials and thoroughly discuss various self-assembly techniques in depth. We will also summarize the latest studies that used the OPLI technique for label-free biosensing applications and divide them into several aspects for further discussion. Then, we will comprehensively evaluate the strengths and weaknesses of self-assembly techniques and discuss possible future research directions. Finally, we will outlook the upcoming challenges and opportunities for label-free biosensing using the OPLI technique.

Real-Time Tracking of Digestive Behavior of Different Structured Triglycerides Based on Ordered Porous Layer Interferometry

“…Optical information was taken from the back of the digestion tank using a spectrometer to obtain the reflected interference signal of the halogen light source at the SCC films and to obtain the Fabry fringes. It can be seen that the obtained Fabry fringes are sinusoidal, when light is vertically incident on the film, the interference light intensity is shown in eq − ( I 1 and I 2 are the reflected light intensity of upper and lower surfaces respectively). …”

“…According to eq , the maximum of I λ occurs at 2 nd = m λ ( m is the order, m = 1, 2, 3, ...). Therefore, the wavelength of the interference peak is directly related to n or d , so the OT of the film can be calculated when the order and wavelength are known. − …”

Measurement of enzyme activity of insoluble substrates based on ordered porous layer interferometry and the application in evaluation of thrombolytic drugs

“…12,13 They offer a unique opportunity to dynamically monitor the interaction processes between large biomolecules, yielding results that traditional analysis methods often find elusive. 14–16 Based on this, self-assembled silica colloidal crystal (SCC) thin film interferometric substrates, boasting high specific surface area, high ordering, 17 high stability, 18 and a controllable design, have been employed as interferometric substrates to conceive an Ordered Porous Layer Interference (OPLI) system. 15–19 Contrasting with diffraction peak positions that depend on the periodic structures and average refractive index, the interference fringes of the ordered porous layer hinge on the Optical Thickness (OT) value, 14 which is the product of the average refractive index ‘ n ’ and the physical thickness ‘ d ’.…”

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

“…Constructed SCC films with monodispersed silica particles have a 3D ordered porous structure. Thus, one of the optical properties of the films is interference, 42 which follows the Fabry−Perot film interference formula:…”

“…Constructed SCC films with monodispersed silica particles have a 3D ordered porous structure. Thus, one of the optical properties of the films is interference, which follows the Fabry–Perot film interference formula: italicm λ = normal2 italicn italicd Where m is the order of the interferometric fringes and λ is the wavelength of interferometric peaks. λ is connected to n (the average refractive index of the film) and d (the film thickness).…”