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Scientific Papers
Publications citing the applications of openQCM (by Novaetech S.r.l.) instruments and accessories in scientific research.
The list of scientific papers published on the most important journals showing the usage of openQCM in several scientific fields, such as thin film deposition, chemical sensors, biological research and biosensors.
Because of the large number of publications, we are reorganizing everything by subject areas. This will take some time. Thank you for your patience
2025
Kundu, Susmita; Jindal, Komal; Ghosh, Soumya; Mondal, Jagannath; Haldar, Ritesh
Engineered dynamic configuration of nanopores to access enhanced diffusion and selectivity for aliphatic isomers Journal Article
In: 2025.
Abstract | Links | BibTeX | Tags: correlated dynamics, diffusion, hexane isomer, MOF thin film, openQCM, QCM, Quartz Crystal Microbalance (QCM)
@article{kundu2025engineered,
title = {Engineered dynamic configuration of nanopores to access enhanced diffusion and selectivity for aliphatic isomers},
author = {Susmita Kundu and Komal Jindal and Soumya Ghosh and Jagannath Mondal and Ritesh Haldar},
url = {https://chemrxiv.org/engage/chemrxiv/article-details/68af2bda23be8e43d65788e9},
doi = {https://doi.org/10.26434/chemrxiv-2025-xn2c4},
year = {2025},
date = {2025-08-31},
urldate = {2025-08-31},
abstract = {Molecular diffusion in porous solids (metal-organic and covalent organic frameworks, zeolites) can be regulated by engineering the chemical environment of the nanochannels. Selective chemical interactions between the nanochannel surface and diffusing molecules enable discrimination at the molecular level, a feature critical for the development of high-performance chemical separation membranes. A major challenge, however, is to concurrently achieve rapid molecular diffusion and high selectivity, as these attributes exhibit an intrinsic trade-off. In this communication we introduce a de novo methodology exploring the rotational dynamics of the nanochannel chemical components and realize simultaneous enhancement of both diffusion and selectivity for aliphatic chemical isomers (branched hexanes). The methodology utilizes crystalline metal-organic framework thin film architecture akin to membrane structures, supported by a comprehensive experimental and simulation framework to achieve the dual objectives effectively},
keywords = {correlated dynamics, diffusion, hexane isomer, MOF thin film, openQCM, QCM, Quartz Crystal Microbalance (QCM)},
pubstate = {published},
tppubtype = {article}
}
Molecular diffusion in porous solids (metal-organic and covalent organic frameworks, zeolites) can be regulated by engineering the chemical environment of the nanochannels. Selective chemical interactions between the nanochannel surface and diffusing molecules enable discrimination at the molecular level, a feature critical for the development of high-performance chemical separation membranes. A major challenge, however, is to concurrently achieve rapid molecular diffusion and high selectivity, as these attributes exhibit an intrinsic trade-off. In this communication we introduce a de novo methodology exploring the rotational dynamics of the nanochannel chemical components and realize simultaneous enhancement of both diffusion and selectivity for aliphatic chemical isomers (branched hexanes). The methodology utilizes crystalline metal-organic framework thin film architecture akin to membrane structures, supported by a comprehensive experimental and simulation framework to achieve the dual objectives effectively
Ismael, Ali; Wang, Xintai; Alanazi, Bashayr; Al-Jobory, Alaa; Lambert, Colin J.
In: Small, vol. n/a, no. n/a, pp. e07988, 2025.
Abstract | Links | BibTeX | Tags: layer-by-layer fabrication, molecular electronics, nano-fabrication, openQCM, Quartz Crystal Microbalance (QCM), thermoelectric optimization
@article{https://doi.org/10.1002/smll.202507988,
title = {Layer-by-Layer Fabrication of Fullerene-Intercalated Orthogonal Molecular Architectures Enhances Thermoelectric Behavior of Graphene-Based Nanodevices},
author = {Ali Ismael and Xintai Wang and Bashayr Alanazi and Alaa Al-Jobory and Colin J. Lambert},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/smll.202507988},
doi = {https://doi.org/10.1002/smll.202507988},
year = {2025},
date = {2025-08-29},
journal = {Small},
volume = {n/a},
number = {n/a},
pages = {e07988},
abstract = {Abstract Despite the significant potential of molecular-scale devices for miniaturized electronics and energy conversion applications, conventional self-assembled monolayers (SAMs) exhibit limitations in simultaneously optimizing electrical conductivity and thermopower due to constrained electronic pathway modulation. This study demonstrates a molecular engineering strategy employing a discretely arranged conjugated molecular backbone to construct ordered cage-like supramolecular cavities, enabling controlled intercalation of fullerene within bipyridine-based SAMs grown on graphene-substrates. Quartz crystal microbalance and atomic force microscopy measurements confirmed the structural integrity of the fullerene-trapped SAMs. Notably, intercalation efficiency was significantly enhanced upon incorporation of an additional zinc tetraphenylporphyrin (ZnTPP) “cap” on top of SAMs, which prevented the loss of fullerene trapped within the cages. Electrical characterization via Eutectic Gallium-Indium (EGaIn)-probe measurements revealed that fullerene-intercalated SAMs exhibited an 8.3-fold higher normalized conductance compared to unintercalated counterparts, without reducing the Seebeck coefficient. Theoretical calculations attributed this enhancement to fullerene-induced Fano-resonance near the Fermi level, which amplified electron transmission. The Seebeck coefficient reached ∼60 µV K−1 through series interface of “slippery” pyridine-zinc coordination and ZnTPP-graphene π-π coupling, while fullerene doping resulted in a similar magnitude. This cage-like intercalation strategy proves effective for decoupling electrical conductivity and the Seebeck coefficient of SAMs, providing a robust approach for synergistic thermoelectric parameter optimization in molecular junctions.},
keywords = {layer-by-layer fabrication, molecular electronics, nano-fabrication, openQCM, Quartz Crystal Microbalance (QCM), thermoelectric optimization},
pubstate = {published},
tppubtype = {article}
}
Abstract Despite the significant potential of molecular-scale devices for miniaturized electronics and energy conversion applications, conventional self-assembled monolayers (SAMs) exhibit limitations in simultaneously optimizing electrical conductivity and thermopower due to constrained electronic pathway modulation. This study demonstrates a molecular engineering strategy employing a discretely arranged conjugated molecular backbone to construct ordered cage-like supramolecular cavities, enabling controlled intercalation of fullerene within bipyridine-based SAMs grown on graphene-substrates. Quartz crystal microbalance and atomic force microscopy measurements confirmed the structural integrity of the fullerene-trapped SAMs. Notably, intercalation efficiency was significantly enhanced upon incorporation of an additional zinc tetraphenylporphyrin (ZnTPP) “cap” on top of SAMs, which prevented the loss of fullerene trapped within the cages. Electrical characterization via Eutectic Gallium-Indium (EGaIn)-probe measurements revealed that fullerene-intercalated SAMs exhibited an 8.3-fold higher normalized conductance compared to unintercalated counterparts, without reducing the Seebeck coefficient. Theoretical calculations attributed this enhancement to fullerene-induced Fano-resonance near the Fermi level, which amplified electron transmission. The Seebeck coefficient reached ∼60 µV K−1 through series interface of “slippery” pyridine-zinc coordination and ZnTPP-graphene π-π coupling, while fullerene doping resulted in a similar magnitude. This cage-like intercalation strategy proves effective for decoupling electrical conductivity and the Seebeck coefficient of SAMs, providing a robust approach for synergistic thermoelectric parameter optimization in molecular junctions.
Norvilaite, O.; Lindsay, C.; Rymaruk, M. J.; Taylor, P.; Armes, S. P.
Synergistic Stabilization of Oil-in-Water Emulsions Using a Binary Mixture of Chitosan and Hydroxypropyl Cellulose Journal Article
In: Langmuir, vol. 0, no. 0, pp. null, 2025, (PMID: 40875375).
Abstract | Links | BibTeX | Tags: Biopolymers, cellulose, emulsions, lipids, Liquids, openQCM NEXT, QCM-D, Quartz Crystal Microbalance (QCM)
@article{doi:10.1021/acs.langmuir.5c03277,
title = {Synergistic Stabilization of Oil-in-Water Emulsions Using a Binary Mixture of Chitosan and Hydroxypropyl Cellulose},
author = {O. Norvilaite and C. Lindsay and M. J. Rymaruk and P. Taylor and S. P. Armes},
url = {https://doi.org/10.1021/acs.langmuir.5c03277},
doi = {10.1021/acs.langmuir.5c03277},
year = {2025},
date = {2025-08-28},
journal = {Langmuir},
volume = {0},
number = {0},
pages = {null},
abstract = {A judicious binary mixture of chitosan and hydroxypropyl cellulose (HPC) has been used to prepare a series of oil-in-water emulsions via high-shear homogenization at pH 4.9. Employing either biopolymer alone results in markedly inferior emulsion stability, suggesting a synergistic effect. Laser diffraction studies indicate that an optimum chitosan/HPC mass ratio of 5:5 produces the finest, most stable droplets. As expected, smaller oil droplets are produced when employing either higher shear or higher biopolymer concentration, and the mean droplet diameter can be tuned from 5 to 30 μm by adjusting these two parameters. However, the droplet diameter is surprisingly insensitive to the oil mass fraction. Such emulsions remain stable between pH 2.6 and pH 5.9. This binary stabilizer approach works well for a range of model oils. Aqueous electrophoresis measurements indicate that the chitosan component confers substantial cationic surface charge on the droplets. After homogenization, the mean droplet diameter can be gradually increased in a relatively controlled manner by storing the emulsion at 40 °C for up to 48 h. Given the biodegradable and biorenewable nature of chitosan and HPC, the versatile nature of this dual emulsifier system suggests its suitability for a wide range of formulations.},
note = {PMID: 40875375},
keywords = {Biopolymers, cellulose, emulsions, lipids, Liquids, openQCM NEXT, QCM-D, Quartz Crystal Microbalance (QCM)},
pubstate = {published},
tppubtype = {article}
}
A judicious binary mixture of chitosan and hydroxypropyl cellulose (HPC) has been used to prepare a series of oil-in-water emulsions via high-shear homogenization at pH 4.9. Employing either biopolymer alone results in markedly inferior emulsion stability, suggesting a synergistic effect. Laser diffraction studies indicate that an optimum chitosan/HPC mass ratio of 5:5 produces the finest, most stable droplets. As expected, smaller oil droplets are produced when employing either higher shear or higher biopolymer concentration, and the mean droplet diameter can be tuned from 5 to 30 μm by adjusting these two parameters. However, the droplet diameter is surprisingly insensitive to the oil mass fraction. Such emulsions remain stable between pH 2.6 and pH 5.9. This binary stabilizer approach works well for a range of model oils. Aqueous electrophoresis measurements indicate that the chitosan component confers substantial cationic surface charge on the droplets. After homogenization, the mean droplet diameter can be gradually increased in a relatively controlled manner by storing the emulsion at 40 °C for up to 48 h. Given the biodegradable and biorenewable nature of chitosan and HPC, the versatile nature of this dual emulsifier system suggests its suitability for a wide range of formulations.
Reichert, Per; Malhotra, Jaskaran Singh; Krishnan, Deepthy; Evli, Sinem; Yamunan, Srihari; Duarte, Clara Dávila; Kubus, Mariusz; Sundberg, Jonas
Surface-Mounted Metal-Organic Framework for the Adsorption and Sensing of Monoaromatic Pollutants in Water Using Quartz Crystal Microbalance Journal Article
In: Advanced Materials Technologies, vol. n/a, no. n/a, pp. e01340, 2025.
Abstract | Links | BibTeX | Tags: Adsorption, metal-organic frameworks, openQCM NEXT, pollution, QCM-D, Quartz Crystal Microbalance (QCM), sensors
@article{https://doi.org/10.1002/admt.202501340,
title = {Surface-Mounted Metal-Organic Framework for the Adsorption and Sensing of Monoaromatic Pollutants in Water Using Quartz Crystal Microbalance},
author = {Per Reichert and Jaskaran Singh Malhotra and Deepthy Krishnan and Sinem Evli and Srihari Yamunan and Clara Dávila Duarte and Mariusz Kubus and Jonas Sundberg},
url = {https://advanced.onlinelibrary.wiley.com/doi/abs/10.1002/admt.202501340},
doi = {https://doi.org/10.1002/admt.202501340},
year = {2025},
date = {2025-08-26},
journal = {Advanced Materials Technologies},
volume = {n/a},
number = {n/a},
pages = {e01340},
abstract = {Abstract Environmental pollution from industrial and anthropogenic activities pose a threat to this access to clean water. Advanced chemical sensors that are simple-to-operate can offer high spatial and temporal resolution, increasing the understanding of the source, fate and distribution of pollutants. One class of highly water-soluble pollutants are benzene, toluene, ethylbenzene and xylene isomers (collectively referred to as BTEX). These compounds are prevalent specifically in fossil fuels and are therefore often found in areas surrounding processing and storage facilities. Selective sensing of chemicals in water is challenging due to the cross-reactivity toward water. Porous metal-organic frameworks have shown promise as analyte-receptors due to the possibility to tune their structure for selective adsorption. It is hypothesized that a hydrophobic MOF with pore dimensions similar to the BTEX molecules will selectively partition these analytes from water. In this study, it is have specifically investigated UHMOF-100, a material previously shown to be highly water-repellent with narrow pores hypothesized to selectively adsorb non-polar compounds. Bulk adsorption experiments confirmed the ability of UHMOF-100 to rapidly adsorb BTEX from water, demonstrating high mass capacities influenced by a complex interplay of water solubility, molecular size, and guest–host interactions. Building upon this, UHMOF-100 thin films on quartz crystal microbalance (QCM) resonators using a layer-by-layer technique is fabricated. The functionalized QCM sensors successfully detected individual BTEX species in water within a 0–50 mg L−1 range, with quantifiable responses as low as 5 mg L−1. The sensors showed low cross-sensitivity toward polar contaminants and demonstrated both chemical stability and mechanical robustness under continuous flow. This work presents, to the knowledge, the first example of a MOF-based QCM sensor for BTEX detection in water, demonstrating the potential of suitably designed porous materials for challenging aqueous sensing applications.},
keywords = {Adsorption, metal-organic frameworks, openQCM NEXT, pollution, QCM-D, Quartz Crystal Microbalance (QCM), sensors},
pubstate = {published},
tppubtype = {article}
}
Abstract Environmental pollution from industrial and anthropogenic activities pose a threat to this access to clean water. Advanced chemical sensors that are simple-to-operate can offer high spatial and temporal resolution, increasing the understanding of the source, fate and distribution of pollutants. One class of highly water-soluble pollutants are benzene, toluene, ethylbenzene and xylene isomers (collectively referred to as BTEX). These compounds are prevalent specifically in fossil fuels and are therefore often found in areas surrounding processing and storage facilities. Selective sensing of chemicals in water is challenging due to the cross-reactivity toward water. Porous metal-organic frameworks have shown promise as analyte-receptors due to the possibility to tune their structure for selective adsorption. It is hypothesized that a hydrophobic MOF with pore dimensions similar to the BTEX molecules will selectively partition these analytes from water. In this study, it is have specifically investigated UHMOF-100, a material previously shown to be highly water-repellent with narrow pores hypothesized to selectively adsorb non-polar compounds. Bulk adsorption experiments confirmed the ability of UHMOF-100 to rapidly adsorb BTEX from water, demonstrating high mass capacities influenced by a complex interplay of water solubility, molecular size, and guest–host interactions. Building upon this, UHMOF-100 thin films on quartz crystal microbalance (QCM) resonators using a layer-by-layer technique is fabricated. The functionalized QCM sensors successfully detected individual BTEX species in water within a 0–50 mg L−1 range, with quantifiable responses as low as 5 mg L−1. The sensors showed low cross-sensitivity toward polar contaminants and demonstrated both chemical stability and mechanical robustness under continuous flow. This work presents, to the knowledge, the first example of a MOF-based QCM sensor for BTEX detection in water, demonstrating the potential of suitably designed porous materials for challenging aqueous sensing applications.
Tozzetti, Martina; Martina, Maria Raffaella; Lucchesi, Giacomo; Vasa, Kristian; Ishaq, Ahtsham; Marsili, Laura; Procacci, Piero; Menichetti, Stefano; Caminati, Gabriella
Ultrasensitive Detection of FKBP12 Using a Synthetic Receptor-Functionalized QCM Nanoplatform Journal Article
In: Advanced Sensor Research, vol. n/a, no. n/a, pp. e00053, 2025.
Abstract | Links | BibTeX | Tags: biomarker sensing, FKBP12 detection, nanosensors, openQCM Wi2, point-of-care diagnostics, Quartz Crystal Microbalance (QCM), Self-Assembled Monolayers (SAMs), synthetic receptors
@article{https://doi.org/10.1002/adsr.202500053,
title = {Ultrasensitive Detection of FKBP12 Using a Synthetic Receptor-Functionalized QCM Nanoplatform},
author = {Martina Tozzetti and Maria Raffaella Martina and Giacomo Lucchesi and Kristian Vasa and Ahtsham Ishaq and Laura Marsili and Piero Procacci and Stefano Menichetti and Gabriella Caminati},
url = {https://advanced.onlinelibrary.wiley.com/doi/abs/10.1002/adsr.202500053},
doi = {https://doi.org/10.1002/adsr.202500053},
year = {2025},
date = {2025-08-07},
journal = {Advanced Sensor Research},
volume = {n/a},
number = {n/a},
pages = {e00053},
abstract = {Abstract FKBP12, a peptidyl-prolyl isomerase implicated in cancer, neurodegenerative diseases, and post-transplant anti-rejection mechanisms, represents a critical biomarker for early diagnosis and monitoring. Here, a novel diagnostic nanoplatform is presented for the detection of FKBP12 at nanomolar to picomolar concentrations in biological fluids. The platform integrates a gold-coated Quartz Crystal Microbalance (QCM) functionalized with a synthetic receptor (GPS-SH1) and spacers within a Self-Assembled Monolayer (SAM), enabling direct and label-free detection of FKBP12 in complex biological samples. A careful strategy for the in-silico design and custom synthesis of the receptor is adopted, ensuring optimal binding affinity and additional chemical functionalities for surface chemisorption. The designed nano-architecture demonstrates exceptional sensitivity, with a detection limit in the picomolar range, and high selectivity, as confirmed by minimal interference from abundant serum proteins such as Serum Albumin and Immune Gamma Globulin. Furthermore, the SAM-functionalized sensors exhibit remarkable stability, retaining functionality for up to six months under storage conditions. This work not only advances the field of nanoscale biosensing but also provides a robust, reusable tool for FKBP12 detection, with potential applications in point-of-care diagnostics and personalized medicine. The platform's ability to operate in biologically relevant environments underscores its promise for real-world healthcare applications, including early disease diagnostics.},
keywords = {biomarker sensing, FKBP12 detection, nanosensors, openQCM Wi2, point-of-care diagnostics, Quartz Crystal Microbalance (QCM), Self-Assembled Monolayers (SAMs), synthetic receptors},
pubstate = {published},
tppubtype = {article}
}
Abstract FKBP12, a peptidyl-prolyl isomerase implicated in cancer, neurodegenerative diseases, and post-transplant anti-rejection mechanisms, represents a critical biomarker for early diagnosis and monitoring. Here, a novel diagnostic nanoplatform is presented for the detection of FKBP12 at nanomolar to picomolar concentrations in biological fluids. The platform integrates a gold-coated Quartz Crystal Microbalance (QCM) functionalized with a synthetic receptor (GPS-SH1) and spacers within a Self-Assembled Monolayer (SAM), enabling direct and label-free detection of FKBP12 in complex biological samples. A careful strategy for the in-silico design and custom synthesis of the receptor is adopted, ensuring optimal binding affinity and additional chemical functionalities for surface chemisorption. The designed nano-architecture demonstrates exceptional sensitivity, with a detection limit in the picomolar range, and high selectivity, as confirmed by minimal interference from abundant serum proteins such as Serum Albumin and Immune Gamma Globulin. Furthermore, the SAM-functionalized sensors exhibit remarkable stability, retaining functionality for up to six months under storage conditions. This work not only advances the field of nanoscale biosensing but also provides a robust, reusable tool for FKBP12 detection, with potential applications in point-of-care diagnostics and personalized medicine. The platform's ability to operate in biologically relevant environments underscores its promise for real-world healthcare applications, including early disease diagnostics.
Samiei, Sepehr; Kalantarian, Asadollah; zad, Azam Iraji; Darmiani, Narges
Room-temperature ethylene glycol sensor based on cuprous oxide/MXene films Journal Article
In: Nature: Scientific Reports, vol. 15, no. 1, pp. 28639, 2025, ISSN: 2045-2322.
Abstract | Links | BibTeX | Tags: Cu2O/MXene bilayer, Ethylene glycol (EG), Gas sensors, MXene, openQCM sensors, Quartz Crystal Microbalance (QCM)
@article{Samiei2025,
title = {Room-temperature ethylene glycol sensor based on cuprous oxide/MXene films},
author = {Sepehr Samiei and Asadollah Kalantarian and Azam Iraji zad and Narges Darmiani},
url = {https://doi.org/10.1038/s41598-025-12019-1},
doi = {10.1038/s41598-025-12019-1},
issn = {2045-2322},
year = {2025},
date = {2025-08-05},
urldate = {2025-08-05},
journal = {Nature: Scientific Reports},
volume = {15},
number = {1},
pages = {28639},
abstract = {This study demonstrates a high-performance room-temperature ethylene glycol (EG) gas sensor using Cu2O/MXene bilayer films on quartz crystal microbalance (QCM) substrates, addressing critical needs for industrial safety and environmental monitoring. The fabricated sensors were systematically characterized by XRD, FTIR, and FESEM, revealing that the Cu2O/MXene bilayer configuration achieved exceptional performance with an ultra-low detection limit of 381 ppb, high sensitivity of 22.8 Hz/ppm, and excellent selectivity compared to individual Cu2O, MXene, or their mixture films. The enhanced sensing capability originates from synergistic effects between p-type Cu2O and conductive MXene, forming a Schottky junction that facilitates charge transfer and promotes EG adsorption through combined physisorption mechanisms involving hydrogen bonding with MXene's functional groups (OH, O, F) and interactions with oxygen species on Cu2O nanoparticles. At 72 ppm EG concentration, the bilayer sensor exhibited 12.6-fold, 3.6-fold, and 2.34-fold higher response than pure Cu2O, MXene alone, and their mixture film, respectively. While humidity tests showed a moderateþinspacetextasciitildeþinspace15% response reduction at 60% RH, the Cu2O/MXene bilayer maintained robust performance, establishing it as a cost-effective and reliable room-temperature sensing platform suitable for next-generation gas detection applications in challenging environments.},
keywords = {Cu2O/MXene bilayer, Ethylene glycol (EG), Gas sensors, MXene, openQCM sensors, Quartz Crystal Microbalance (QCM)},
pubstate = {published},
tppubtype = {article}
}
This study demonstrates a high-performance room-temperature ethylene glycol (EG) gas sensor using Cu2O/MXene bilayer films on quartz crystal microbalance (QCM) substrates, addressing critical needs for industrial safety and environmental monitoring. The fabricated sensors were systematically characterized by XRD, FTIR, and FESEM, revealing that the Cu2O/MXene bilayer configuration achieved exceptional performance with an ultra-low detection limit of 381 ppb, high sensitivity of 22.8 Hz/ppm, and excellent selectivity compared to individual Cu2O, MXene, or their mixture films. The enhanced sensing capability originates from synergistic effects between p-type Cu2O and conductive MXene, forming a Schottky junction that facilitates charge transfer and promotes EG adsorption through combined physisorption mechanisms involving hydrogen bonding with MXene's functional groups (OH, O, F) and interactions with oxygen species on Cu2O nanoparticles. At 72 ppm EG concentration, the bilayer sensor exhibited 12.6-fold, 3.6-fold, and 2.34-fold higher response than pure Cu2O, MXene alone, and their mixture film, respectively. While humidity tests showed a moderateþinspacetextasciitildeþinspace15% response reduction at 60% RH, the Cu2O/MXene bilayer maintained robust performance, establishing it as a cost-effective and reliable room-temperature sensing platform suitable for next-generation gas detection applications in challenging environments.
Berisha, A. P.; Mykhaylyk, O. O.; Armes, S. P.; Ambarkar, A.; Malde, C.
Determination of Both Wet and Dry Mass of Water-Soluble Polymers Adsorbed on Planar Silica Using a Quartz Crystal Microbalance Journal Article
In: Langmuir, vol. 0, no. 0, pp. null, 2025, (PMID: 40587480).
Abstract | Links | BibTeX | Tags: Adsorption, nanoparticles, openQCM NEXT, polymers, QCM-D, Quartz Crystal Microbalance (QCM), sensors, Silica
@article{doi:10.1021/acs.langmuir.5c01380,
title = {Determination of Both Wet and Dry Mass of Water-Soluble Polymers Adsorbed on Planar Silica Using a Quartz Crystal Microbalance},
author = {A. P. Berisha and O. O. Mykhaylyk and S. P. Armes and A. Ambarkar and C. Malde},
url = {https://doi.org/10.1021/acs.langmuir.5c01380},
doi = {10.1021/acs.langmuir.5c01380},
year = {2025},
date = {2025-06-30},
urldate = {2025-06-30},
journal = {Langmuir},
volume = {0},
number = {0},
pages = {null},
abstract = {It is well-established that polymer adsorption at a model planar interface can be studied using a quartz crystal microbalance (QCM). Normally, this technique reports both the adsorbed mass of polymer chains plus any bound or entrained solvent molecules. Thus the total adsorbed amount significantly exceeds that reported by optical reflectometry or determined from adsorption isotherms obtained for colloidal substrates using a supernatant depletion assay. Herein we report a new QCM approach whereby the dry adsorbed amount, Γdry, is obtained directly from the wet (solvated) adsorbed amount, Γwet, by switching from a liquid flow to a flow of nitrogen gas. The latter conditions lead to complete removal of the solvent, leaving only the desolvated adsorbed polymer chains. This strategy is exemplified for the adsorption of two well-known nonionic water-soluble polymers, poly(ethylene glycol) (PEG) and poly(N-vinylpyrrolidone) (PNVP), from aqueous solution onto a model planar substrate (silica). These two systems were selected to facilitate direct comparison with the literature, which validates this new approach.},
note = {PMID: 40587480},
keywords = {Adsorption, nanoparticles, openQCM NEXT, polymers, QCM-D, Quartz Crystal Microbalance (QCM), sensors, Silica},
pubstate = {published},
tppubtype = {article}
}
It is well-established that polymer adsorption at a model planar interface can be studied using a quartz crystal microbalance (QCM). Normally, this technique reports both the adsorbed mass of polymer chains plus any bound or entrained solvent molecules. Thus the total adsorbed amount significantly exceeds that reported by optical reflectometry or determined from adsorption isotherms obtained for colloidal substrates using a supernatant depletion assay. Herein we report a new QCM approach whereby the dry adsorbed amount, Γdry, is obtained directly from the wet (solvated) adsorbed amount, Γwet, by switching from a liquid flow to a flow of nitrogen gas. The latter conditions lead to complete removal of the solvent, leaving only the desolvated adsorbed polymer chains. This strategy is exemplified for the adsorption of two well-known nonionic water-soluble polymers, poly(ethylene glycol) (PEG) and poly(N-vinylpyrrolidone) (PNVP), from aqueous solution onto a model planar substrate (silica). These two systems were selected to facilitate direct comparison with the literature, which validates this new approach.
Ahamed, Afri; Ooi, Chien Wei; Lim, Hui Jean; Ramakrishnan, N.; Saha, Tridib
Elliptical Electrode Designs in Quartz Crystal Microbalances: Enhancing Sensitivity in Liquid Biosensing Applications Journal Article
In: Sensors and Actuators A: Physical, pp. 116392, 2025, ISSN: 0924-4247.
Abstract | Links | BibTeX | Tags: Deionised Water (DI Water), Elliptical Electrodes, Liquid Droplet Detection, openQCM Q-1, Protein Sensing, Quartz Crystal Microbalance (QCM)
@article{AHAMED2025116392,
title = {Elliptical Electrode Designs in Quartz Crystal Microbalances: Enhancing Sensitivity in Liquid Biosensing Applications},
author = {Afri Ahamed and Chien Wei Ooi and Hui Jean Lim and N. Ramakrishnan and Tridib Saha},
url = {https://www.sciencedirect.com/science/article/pii/S0924424725001980},
doi = {https://doi.org/10.1016/j.sna.2025.116392},
issn = {0924-4247},
year = {2025},
date = {2025-03-03},
urldate = {2025-01-01},
journal = {Sensors and Actuators A: Physical},
pages = {116392},
abstract = {The demand for highly sensitive and versatile sensors is rapidly growing in biomedical applications, where specific, sensitive, and rapid detection are essential. Quartz crystal microbalance (QCM) is a popular analytical tool for such applications due to its high sensitivity and real-time monitoring capabilities. However, conventional QCM-based biosensing assays often suffer from poor sensitivity and high sample consumption, limiting their practicality. This study introduces a modified electrode design and a single droplet-based assay to enhance QCM-based bio-detection. Through extensive experiments, including contact angle analysis, damping, and viscosity measurements, we identified an optimal elliptical electrode design for single droplet-based liquid sensing. Using QCM crystals coated with molecularly imprinted polydopamine (MIPDA) sensing films containing recognition sites for detecting pepsin as a model protein, we demonstrate that QCM crystals with elliptical electrodes exhibit up to 10 times higher sensitivity than the industry-standard 1-inch circular QCM crystal. Additionally, the optimized QCM crystals showed linear sensitivity over a wider volume range, providing consistent detection at 250Hz/μl compared to the circular crystal's narrower range at 50Hz/μl. These findings establish a foundation for next-generation QCM platforms with superior sensitivity, reduced sample requirements, and broader adaptability, paving the way for advancements in biomedical diagnostics and environmental monitoring.},
keywords = {Deionised Water (DI Water), Elliptical Electrodes, Liquid Droplet Detection, openQCM Q-1, Protein Sensing, Quartz Crystal Microbalance (QCM)},
pubstate = {published},
tppubtype = {article}
}
The demand for highly sensitive and versatile sensors is rapidly growing in biomedical applications, where specific, sensitive, and rapid detection are essential. Quartz crystal microbalance (QCM) is a popular analytical tool for such applications due to its high sensitivity and real-time monitoring capabilities. However, conventional QCM-based biosensing assays often suffer from poor sensitivity and high sample consumption, limiting their practicality. This study introduces a modified electrode design and a single droplet-based assay to enhance QCM-based bio-detection. Through extensive experiments, including contact angle analysis, damping, and viscosity measurements, we identified an optimal elliptical electrode design for single droplet-based liquid sensing. Using QCM crystals coated with molecularly imprinted polydopamine (MIPDA) sensing films containing recognition sites for detecting pepsin as a model protein, we demonstrate that QCM crystals with elliptical electrodes exhibit up to 10 times higher sensitivity than the industry-standard 1-inch circular QCM crystal. Additionally, the optimized QCM crystals showed linear sensitivity over a wider volume range, providing consistent detection at 250Hz/μl compared to the circular crystal's narrower range at 50Hz/μl. These findings establish a foundation for next-generation QCM platforms with superior sensitivity, reduced sample requirements, and broader adaptability, paving the way for advancements in biomedical diagnostics and environmental monitoring.
