Spectroscopic Ellipsometry and Quartz Crystal Microbalance with Dissipation for the Assessment of Polymer Layers and for the Application in Biosensing

Abstract

Polymers represent materials that are applied in almost all areas of modern life, therefore, the characterization of polymer layers using different methods is of great importance. In this review, the main attention is dedicated to the non-invasive and label-free optical and acoustic methods, namely spectroscopic ellipsometry (SE) and quartz crystal microbalance with dissipation (QCM-D). The specific advantages of these techniques applied for in situ monitoring of polymer layer formation and characterization, biomolecule immobilization, and registration of specific interactions were summarized and discussed. In addition, the exceptional benefits and future perspectives of combined spectroscopic ellipsometry and QCM-D (SE/QCM-D) in one measurement are overviewed. Recent advances in the discussed area allow us to conclude that especially significant breakthroughs are foreseen in the complementary application of both QCM-D and SE techniques for the investigation of polymer structure and assessment of the interaction between biomolecules such as antigens and antibodies, receptors and ligands, and complementary DNA strands.

QCM-D Investigations of Anisotropic Particle Deposition Kinetics: Evidences of the Hydrodynamic Slip Mechanisms

“…Because of its significance, nanoparticle and microparticle adsorption kinetics was extensively studied by a variety of experimental techniques such as optical microscopy, 22 atomic force microscopy (AFM), 23 − 25 scanning electron microscopy (SEM), 25 − 28 ellipsometry, 29 − 31 reflectometry, 32 , 33 surface plasmon resonance, 34 and electrokinetic methods. 35 , 36 However, these techniques cannot provide valid information about the adhesive contact strength between the particles and the substrate surfaces.…”

“…Because of its significance, nanoparticle and microparticle adsorption kinetics was extensively studied by a variety of experimental techniques such as optical microscopy, atomic force microscopy (AFM), − scanning electron microscopy (SEM), − ellipsometry, − reflectometry, , surface plasmon resonance, and electrokinetic methods. , However, these techniques cannot provide valid information about the adhesive contact strength between the particles and the substrate surfaces. In this respect, the quartz crystal microbalance (QCM) method exhibits pronounced advantages, enabling precise, in situ deposition/desorption kinetic measurements for the nano- and microparticles under flow conditions. − However, these investigations were almost exclusively focused on spherical particles.…”

Recent Developments in the Field of Optical Immunosensors Focusing on a Label-Free, White Light Reflectance Spectroscopy-Based Immunosensing Platform

“…Thus, some of these articles describe optical immunosensors that have been developed for various (groups of) biomolecules [ 1 , 41 , 42 ], such as COVID-19-related biomarkers [ 43 , 44 , 45 , 46 ]. Immunosensing based on optical fiber technology [ 47 , 48 ] and application of spectroscopic ellipsometry to immunosensing [ 49 ] have been presented in recent reviews. Multiplexed optical immunosensors that are capable of simultaneously detecting/quantifying more than one analyte of diagnostic interest in the same sample and can be used for Point-of-Care applications have been recently presented as well [ 2 , 50 ].…”

Biochemical Interactions through Microscopic Techniques: Structural and Molecular Characterization

“…Monitoring the affinity-based interaction of biochemicals in different environments; the label-free and real-time detection of pesticides, explosives, bacteria, viruses, toxins, allergens, and biomedical analytes [41][42][43] Spectroscopic ellipsometry Bio-sensing; surface and physical properties of thin-film materials [44,45] X-ray crystallography Study of crystal structures at the level of atomic resolution; identification of the binding modes of biochemical interactions, e.g., protein-ligand interactions; structure-based drug design [46] Transmission electron microscopy (TEM) Structural and chemical characterization, extravasation, and subcellular distribution of particles at the nanoscale with a resolution of 2 nm [47,48] Fluorescence correlation spectroscopy (FCS) FCS can monitor the interactions between biomolecules and nanoparticles, e.g., FCS was used to quantify the functionalization efficiency of ligands (for example, avidin and antibody binding fragments (Fabs)) on the surface of nanoparticles [49,50] Confocal laser scanning microscopy (CLSM) CLSM allows optical slicing through tissues, thus enabling precise real-time imaging of liver cells, organelles, and intracellular trafficking of nanoparticles, such as the endosomal escape ability of nanoparticles [51] Intravital real-time CLSM (IVRT-CLSM)…”