Why QCM-D Is the Preferred Real-Time Method for Surface Analysis

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For centuries, people have been researching and developing different types of surfaces for different applications known as surface modifications. As a result, today we have self-cleaning windows, superhydrophobic glass, cell-friendly implants, and scratch-resistant surfaces.

It has always been the case that a whole series of processes need to be carried out. First, researchers must figure out what surface properties are needed. Second, how to modify and characterize the surface properties. Several tests need to be done to confirm that we have the right surface properties that we have planned.

Going the Quartz Crystal Way

Quartz crystal microbalance with dissipation monitoring (QCM-D) is a powerful method for monitoring of molecular interactions at surfaces and interfaces and thin film properties

Measuring changes of two parameters, the resonance frequency, Δf, and the energy dissipation, ΔD, of an oscillating quartz crystal disk, this surface sensitive analytical technique can provide information on mass, thickness, and viscoelastic properties of layers at the sensor surface. The method can, for example, be used to systematically study the adsorption behavior of molecules of interest to relevant surfaces in a wide range of solution mixtures.

QCM-D analysis provides a fundamental understanding of processes and the ability to optimize products and processes for authentic conditions.

The QCM-D technology was developed and commercialized in the 1990s by scientists at Chalmers University of Technology in Sweden. Since then, the QCM-D community has grown along with interest in the capabilities of this technology. Today, the instruments are used in research facilities around the world in a wide range of application areas such as in pharmaceuticals, biotechnology, energy, polymers, electronics, and many others.

Figure 1: Frequency (blue) and dissipation (red) shifts for antibody assay construction: immobilization of coupling molecules, streptavidin, and biotinylated protein A, followed by capture of anti-BSA and antigen binding, BSA.

Versatile Conditions

QCM-D can be used under various experimental conditions, such as in controlled humidity, controlled pressure, in harsh solvents, and in the gas phase. The hardware also allows for combination and simultaneous measurements with complementary methods such as electrochemistry, ellipsometry, and microscopy.

The detection range is ~1 Å to 1 um, depending on the layer properties, which allows for molecules such as biomolecules, surfactants, polymers, nanoparticles, cells, and other structures in the same size range to be studied.

Examples of processes that can be analyzed with QCM-D:

Adsorption / Desorption
Binding / Release
Buildup/Degradation
Crosslinking
Swelling / Collapse

Figure 2: Schematic illustration of processes that can be studied with QCM-D.
(Top) Molecular adsorption, desorption, and binding
(Middle) Soil swelling and removal
(Bottom) Crosslinking or collapse of polymer brush

With nanogram precision, QCM-D analysis allows for researchers to follow molecular events at the surface as they happen, and quantify mass, thickness, and structural properties of surface adhering layers. DKSH provides advanced QCM-D for surface analysis offering a new perspective in the studies of molecule-surface interactions. Learn more about it here.

The global meat substitutes sector is worth over USD 20 billion and Euromonitor projects that it is set to exceed USD 23 billion by 2024. In Asia, the market for plant-based products is increasing as well. According to consumer data group Nielsen, sales of plant-based meat substitutes within the region rose by 264 percent in May 2020. Mintel also reported a nearly 40 percent increase in the launches of meat substitute products last year.

The region is witnessing a rising market for “flexitarian” dieters, those who occasionally substitute meat in their diet with plant-based protein. Global Data revealed that approximately 36 percent of Thai consumers eat protein substitutes while over 53 percent of Japanese consumers have tried plant-based foods in search of a healthier lifestyle. Euromonitor’s data shows that there are nearly five million vegetarians in Asia Pacific with India having the largest vegetarian population of over 3.6 million.

The COVID-19 pandemic has also influenced consumers’ food choices and highlighted the importance of health and wellness. It has accelerated the growth of consumers’ interest in plant-based meat alternatives and increased interest in cleaner sources of protein. Post-pandemic surveys show that 49 percent of South Koreans agree that plant-based foods are better for the environment than meat and dairy products.

The main reasons for the increased demand for plant-based foods are improved personal health, as well as increased awareness of environmental sustainability, food safety and animal welfare.

As the industry continues to grow, there are still various challenges it needs to overcome in Asia. Plant-based food manufacturers need to find the best ways to ensure the quality of raw ingredients as well as improve the taste and texture of the food.

As with most food products, any occurrence of an unwanted accident or tainted ingredients may lead to recalls that could make consumers wary of buying and eating these alternatives. With any product recall, consumer confidence and the industry will be affected.

Beyond the quality of ingredients, taste and texture are also obstacles for consumer acceptance. One misconception about plant-based alternatives is they must be as close to meat as possible. In reality, it does not have to simulate meat 100 percent.

The two common parameters to overcome the challenge of product taste and texture are rheological properties and particle characterization. Food rheology is the study of deformation and flow of foods under well-defined conditions and is closely correlated with food texture. Particle characterization is a method often used for better controlling product quality, attaining an understanding of ingredients and enhancing the performance of a product.

Let us use the soybean as an example as the rheological properties and particle size distribution of soy protein is equally important along with the functional properties it possesses. Soybean is a rich and affordable source of plant protein and can be used as a protein supplement or ingredient in many food items.

Meanwhile, soy protein can replace many ingredients in food formulations in meat or dairy products without changing the taste and quality of foods. It can be used as an emulsifier, texture enhancer and an ingredient to increase or replace protein content in food products like bread, pastry products, beverages and meat.

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About the Author

Roman Ratayczak is the General Manager of Business Development at DKSH Technology, with over 26 years of expertise in management, sales, project leadership, and manufacturing across the automotive and machine tool sectors. A highly innovative professional, Roman brings a wealth of experience in leading teams and driving business success. He has spent over 13 years working in multicultural and global environments, particularly in Korea and Thailand, where his multilingual skills have enhanced his ability to navigate complex, cross-cultural business landscapes.

Roman Ratayczak

Precision Machinery & Semiconductor and Electronics

About the Author

Afzalur Alfan received his M.Sc in materials science & engineering from National University Malaysia. He has been with DKSH for 8 years and is now serving as Senior Manager for the Materials Science Team in Indonesia. He has experience in several scientific instrumentation techniques such as laser diffraction, dynamic light scattering, differential scanning calorimetry and rheology.

Afzalur Alfan

Material Science

About the Author

Carissa Lim is the Senior Application Specialist at DKSH Singapore, bringing over 18 years of diverse experience to her role. Her expertise spans project management, training coordination, scientific research, and quality assurance. Certified as a Food Safety Preventive Control Alliance (FSPCA) Preventive Controls Qualified Individual for Human Food, she also has expertise as an internal auditor for both Hazard Analysis Critical Control Point (HACCP) and Good Distribution Practice for Medical Devices (GDPMDS). Previously, Carissa spent more than 9 years in the food safety industry, where she leverages her knowledge in microbiology and food science education to assist food processors in developing and implementing effective food safety strategies and testing methods.

Carissa Lim

Food Science

About the Author

Cathleen Lin is the General Manager of Scientific Instrumentation at DKSH Business Unit Technology, China. With an extensive background in the instrumentation industry, she brings over 25 years of experience in sales and marketing, product management, and business development in China. She holds a Bachelor Degree in Applied Chemistry from Fudan university, and an MBA from East China University of Science and Technology (ECUST).

Cathleen Lin

Material Science

About the Author

Hanno Elbraechter joined DKSH in September 2014 as Head Business Unit Technology across 18 countries. He has been transforming sales and service organizations over the last 15 years across Asia to set new standards when it comes to systematic market development, industry specific market penetration and after-sales services combined with state-of-the-art CRM systems. After living for 13 years in China, he recently moved to Singapore with his wife and three kids.

Hanno Elbraechter

Material Science

Why QCM-D Is the Preferred Real-Time Method for Surface Analysis