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Salipante PF. Microfluidic techniques for mechanical measurements of biological samples. BIOPHYSICS REVIEWS 2023; 4:011303. [PMID: 38505816 PMCID: PMC10903441 DOI: 10.1063/5.0130762] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 12/30/2022] [Indexed: 03/21/2024]
Abstract
The use of microfluidics to make mechanical property measurements is increasingly common. Fabrication of microfluidic devices has enabled various types of flow control and sensor integration at micrometer length scales to interrogate biological materials. For rheological measurements of biofluids, the small length scales are well suited to reach high rates, and measurements can be made on droplet-sized samples. The control of flow fields, constrictions, and external fields can be used in microfluidics to make mechanical measurements of individual bioparticle properties, often at high sampling rates for high-throughput measurements. Microfluidics also enables the measurement of bio-surfaces, such as the elasticity and permeability properties of layers of cells cultured in microfluidic devices. Recent progress on these topics is reviewed, and future directions are discussed.
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Affiliation(s)
- Paul F. Salipante
- National Institute of Standards and Technology, Polymers and Complex Fluids Group, Gaithersburg, Maryland 20899, USA
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2
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Miranda-Martínez A, Sufrate-Vergara B, Fernández-Puntero B, Alcaide-Martin MJ, Buño-Soto A, Serrano-Olmedo JJ. ANN-Based Discernment of Septic and Inflammatory Synovial Fluid: A Novel Method Using Viscosity Data from a QCR Sensor. SENSORS (BASEL, SWITZERLAND) 2022; 22:9413. [PMID: 36502129 PMCID: PMC9740680 DOI: 10.3390/s22239413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 11/08/2022] [Accepted: 11/30/2022] [Indexed: 06/17/2023]
Abstract
The synovial fluid (SF) analysis involves a series of chemical and physical studies that allow opportune diagnosing of septic, inflammatory, non-inflammatory, and other pathologies in joints. Among the variety of analyses to be performed on the synovial fluid, the study of viscosity can help distinguish between these conditions, since this property is affected in pathological cases. The problem with viscosity measurement is that it usually requires a large sample volume, or the necessary instrumentation is bulky and expensive. This study compares the viscosity of normal synovial fluid samples with samples with infectious and inflammatory pathologies and classifies them using an ANN (Artificial Neural Network). For this purpose, a low-cost, portable QCR-based sensor (10 MHz) was used to measure the viscous responses of the samples by obtaining three parameters: Δf, ΔΓ (parameters associated with the viscoelastic properties of the fluid), and viscosity calculation. These values were used to train the algorithm. Different versions of the ANN were compared, along with other models, such as SVM and random forest. Thirty-three samples of SF were analyzed. Our study suggests that the viscosity characterized by our sensor can help distinguish infectious synovial fluid, and that implementation of ANN improves the accuracy of synovial fluid classification.
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Affiliation(s)
- Andrés Miranda-Martínez
- Centre for Biomedical Technology (CTB), Universidad Politécnica de Madrid (UPM), 28040 Madrid, Spain
| | - Berta Sufrate-Vergara
- Department of Clinical Analysis-Emergency, Hospital Universitario La Paz (HULP), 28046 Madrid, Spain
| | - Belén Fernández-Puntero
- Department of Clinical Analysis-Emergency, Hospital Universitario La Paz (HULP), 28046 Madrid, Spain
| | - María José Alcaide-Martin
- Department of Clinical Analysis-Emergency, Hospital Universitario La Paz (HULP), 28046 Madrid, Spain
| | - Antonio Buño-Soto
- Department of Clinical Analysis-Emergency, Hospital Universitario La Paz (HULP), 28046 Madrid, Spain
| | - José Javier Serrano-Olmedo
- Centre for Biomedical Technology (CTB), Universidad Politécnica de Madrid (UPM), 28040 Madrid, Spain
- Networking Research Center of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Universidad Politécnica de Madrid (UPM), 28040 Madrid, Spain
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Miranda-Martínez A, Yan H, Silveira V, Serrano-Olmedo JJ, Crouzier T. Portable Quartz Crystal Resonator Sensor for Characterising the Gelation Kinetics and Viscoelastic Properties of Hydrogels. Gels 2022; 8:718. [PMID: 36354626 PMCID: PMC9690109 DOI: 10.3390/gels8110718] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/28/2022] [Accepted: 10/31/2022] [Indexed: 10/28/2023] Open
Abstract
Hydrogel biomaterials have found use in various biomedical applications partly due to their biocompatibility and tuneable viscoelastic properties. The ideal rheological properties of hydrogels depend highly on the application and should be considered early in the design process. Rheometry is the most common method to study the viscoelastic properties of hydrogels. However, rheometers occupy much space and are costly instruments. On the other hand, quartz crystal resonators (QCRs) are devices that can be used as low-cost, small, and accurate sensors to measure the viscoelastic properties of fluids. For this reason, we explore the capabilities of a low-cost and compact QCR sensor to sense and characterise the gelation process of hydrogels while using a low sample amount and by sensing two different crosslink reactions: covalent bonds and divalent ions. The gelation of covalently crosslinked mucin hydrogels and physically crosslinked alginate hydrogels could be monitored using the sensor, clearly distinguishing the effect of several parameters affecting the viscoelastic properties of hydrogels, including crosslinking chemistry, polymer concentrations, and crosslinker concentrations. QCR sensors offer an economical and portable alternative method to characterise changes in a hydrogel material's viscous properties to contribute to this type of material design, thus providing a novel approach.
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Affiliation(s)
- Andrés Miranda-Martínez
- Centre for Biomedical Technology (CTB), Universidad Politécnica de Madrid (UPM), 28040 Madrid, Spain
| | - Hongji Yan
- Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH, Royal Institute of Technology, 106 91 Stockholm, Sweden
- AIMES-Center for the Advancement of Integrated Medical and Engineering Sciences, Karolinska Institutet and KTH-Royal Institute of Technology, 114 28 Stockholm, Sweden
- Department of Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Valentin Silveira
- Division of Wood Science and Technology, Department of Forest Biomaterials and Technology, SLU, Swedish University of Agricultural Sciences, 756 51 Uppsala, Sweden
| | - José Javier Serrano-Olmedo
- Centre for Biomedical Technology (CTB), Universidad Politécnica de Madrid (UPM), 28040 Madrid, Spain
- Networking Research Center of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Universidad Politécnica de Madrid (UPM), 28040 Madrid, Spain
| | - Thomas Crouzier
- Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH, Royal Institute of Technology, 106 91 Stockholm, Sweden
- AIMES-Center for the Advancement of Integrated Medical and Engineering Sciences, Karolinska Institutet and KTH-Royal Institute of Technology, 114 28 Stockholm, Sweden
- Department of Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden
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Castro-Balado A, Bandín-Vilar E, Cuartero-Martínez A, García-Quintanilla L, Hermelo-Vidal G, García-Otero X, Rodríguez-Martínez L, Mateos J, Hernández-Blanco M, Aguiar P, Zarra-Ferro I, González-Barcia M, Mondelo-García C, Otero-Espinar FJ, Fernández-Ferreiro A. Cysteamine Eye Drops in Hyaluronic Acid Packaged in Innovative Single-Dose Systems: Stability and Ocular Biopermanence. Pharmaceutics 2022; 14:pharmaceutics14102194. [PMID: 36297629 PMCID: PMC9607622 DOI: 10.3390/pharmaceutics14102194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 10/10/2022] [Accepted: 10/12/2022] [Indexed: 11/05/2022] Open
Abstract
Cystinosis is a rare genetic disorder characterized by the accumulation of cystine crystals in different tissues and organs causing, among other symptoms, severe ocular manifestations. Cysteamine eye drops are prepared in hospital pharmacy departments to facilitate access to treatment, for which vehicles that provide adequate biopermanence, as well as adaptable containers that maintain its stability, are required. Difficulties related to cysteamine preparation, as well as its tendency to oxidize to cystamine, show the importance of conducting rigorous galenic characterization studies. This work aims to develop and characterize an ophthalmic compounded formulation of cysteamine prepared with hyaluronic acid and packaged in innovative single-dose systems. For this task, the effect of different storage temperatures and the presence/absence of nitrogen on the physicochemical stability of the formulation and its packaging was studied in a scaled manner, until reaching the optimal storage conditions. The results showed that 0.55% cysteamine, prepared with hyaluronic acid and packaged in single-dose containers, is stable for 30 days when stored at −20 °C. In addition, opening vials every 4 h at room temperature after 30 days of freezing maintains the stability of the cysteamine formulation for up to 16 h. Moreover, ocular biopermanence studies were conducted using molecular imaging, concluding that the biopermanence offered by the vehicle is not affected by the freezing process, where a half-life of 31.11 min for a hyaluronic acid formulation stored for 30 days at −20 °C was obtained, compared with 14.63 min for 0.9% sodium chloride eye drops.
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Affiliation(s)
- Ana Castro-Balado
- Pharmacy Department, University Clinical Hospital of Santiago de Compostela (SERGAS), 15706 Santiago de Compostela, Spain
- Clinical Pharmacology Group, Health Research Institute of Santiago de Compostela (IDIS), 15706 Santiago de Compostela, Spain
- Pharmacology, Pharmacy and Pharmaceutical Technology Department, Faculty of Pharmacy, University of Santiago de Compostela (USC), 15782 Santiago de Compostela, Spain
| | - Enrique Bandín-Vilar
- Pharmacy Department, University Clinical Hospital of Santiago de Compostela (SERGAS), 15706 Santiago de Compostela, Spain
- Clinical Pharmacology Group, Health Research Institute of Santiago de Compostela (IDIS), 15706 Santiago de Compostela, Spain
- Pharmacology, Pharmacy and Pharmaceutical Technology Department, Faculty of Pharmacy, University of Santiago de Compostela (USC), 15782 Santiago de Compostela, Spain
| | - Andrea Cuartero-Martínez
- Clinical Pharmacology Group, Health Research Institute of Santiago de Compostela (IDIS), 15706 Santiago de Compostela, Spain
| | - Laura García-Quintanilla
- Pharmacy Department, University Clinical Hospital of Santiago de Compostela (SERGAS), 15706 Santiago de Compostela, Spain
- Clinical Pharmacology Group, Health Research Institute of Santiago de Compostela (IDIS), 15706 Santiago de Compostela, Spain
- Pharmacology, Pharmacy and Pharmaceutical Technology Department, Faculty of Pharmacy, University of Santiago de Compostela (USC), 15782 Santiago de Compostela, Spain
| | - Gonzalo Hermelo-Vidal
- Clinical Pharmacology Group, Health Research Institute of Santiago de Compostela (IDIS), 15706 Santiago de Compostela, Spain
| | - Xurxo García-Otero
- Pharmacology, Pharmacy and Pharmaceutical Technology Department, Faculty of Pharmacy, University of Santiago de Compostela (USC), 15782 Santiago de Compostela, Spain
- Molecular Imaging Group, Health Research Institute of Santiago de Compostela (IDIS), 15706 Santiago de Compostela, Spain
| | - Lorena Rodríguez-Martínez
- Clinical Pharmacology Group, Health Research Institute of Santiago de Compostela (IDIS), 15706 Santiago de Compostela, Spain
| | - Jesús Mateos
- Clinical Pharmacology Group, Health Research Institute of Santiago de Compostela (IDIS), 15706 Santiago de Compostela, Spain
| | - Manuela Hernández-Blanco
- Microbiology Department, University Clinical Hospital of Santiago de Compostela (SERGAS), 15706 Santiago de Compostela, Spain
| | - Pablo Aguiar
- Molecular Imaging Group, Health Research Institute of Santiago de Compostela (IDIS), 15706 Santiago de Compostela, Spain
| | - Irene Zarra-Ferro
- Pharmacy Department, University Clinical Hospital of Santiago de Compostela (SERGAS), 15706 Santiago de Compostela, Spain
- Clinical Pharmacology Group, Health Research Institute of Santiago de Compostela (IDIS), 15706 Santiago de Compostela, Spain
| | - Miguel González-Barcia
- Pharmacy Department, University Clinical Hospital of Santiago de Compostela (SERGAS), 15706 Santiago de Compostela, Spain
- Clinical Pharmacology Group, Health Research Institute of Santiago de Compostela (IDIS), 15706 Santiago de Compostela, Spain
| | - Cristina Mondelo-García
- Pharmacy Department, University Clinical Hospital of Santiago de Compostela (SERGAS), 15706 Santiago de Compostela, Spain
- Clinical Pharmacology Group, Health Research Institute of Santiago de Compostela (IDIS), 15706 Santiago de Compostela, Spain
- Correspondence: (C.M.-G.); (F.J.O.-E.); (A.F.-F.)
| | - Francisco J. Otero-Espinar
- Pharmacology, Pharmacy and Pharmaceutical Technology Department, Faculty of Pharmacy, University of Santiago de Compostela (USC), 15782 Santiago de Compostela, Spain
- Correspondence: (C.M.-G.); (F.J.O.-E.); (A.F.-F.)
| | - Anxo Fernández-Ferreiro
- Pharmacy Department, University Clinical Hospital of Santiago de Compostela (SERGAS), 15706 Santiago de Compostela, Spain
- Clinical Pharmacology Group, Health Research Institute of Santiago de Compostela (IDIS), 15706 Santiago de Compostela, Spain
- Correspondence: (C.M.-G.); (F.J.O.-E.); (A.F.-F.)
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Iwashita H, Mabuchi K, Itokawa T, Okajima Y, Suzuki T, Hori Y. Evaluation of the Lubricating Effect of Hyaluronic Acid on Contact Lenses Using a Pendulum-Type Friction Tester Under Mimicking Physiological Conditions. Eye Contact Lens 2022; 48:83-87. [PMID: 35058419 PMCID: PMC8759543 DOI: 10.1097/icl.0000000000000853] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/12/2021] [Indexed: 12/02/2022]
Abstract
OBJECTIVE To evaluate the lubricating effect of hyaluronic acid (HA) on soft contact lenses (SCLs) measured using a pendulum-type friction tester. METHODS We measured the coefficient of friction (CoF) of narafilcon A, delefilcon A, and etafilcon A with polyvinylpyrrolidone (PVP), daily disposable SCL material, using a modified pendulum-type friction tester. Sample SCLs were set on an acrylic plastic half-ball and placed into the polyethylene terephthalate hemisphere cup filled with 0.4 mL of test lubricants that included saline and 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% (wt/vol) HA (molecular weight, 850 kDa). The viscosities of saline and HA were measured using an Ubbelohde viscometer. RESULTS The CoF of the SCL under a low concentration (0.05%) of HA was the lowest and significantly lower than saline in narafilcon A and delefilcon A (P<0.05, Steel multiple comparison test). Under higher HA concentrations (0.3%, 0.4%, and 0.5%), the CoF was significantly higher than that of saline (P<0.01, Steel' multiple comparison test) in all three SCLs. There were no significant differences of CoF among three SCLs in saline and all concentrations of HA. The HA viscosities increased exponentially with the concentration (Y=1.2829e9.286X). CONCLUSION The viscosity of a high concentration of HA may increase the friction of SCLs, which may have a deleterious effect on the ocular surface.
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Affiliation(s)
- Hiroko Iwashita
- Department of Ophthalmology (H.I., K.M., T.I., Y.O., T.S., Y.H.), Faculty of Medicine, Toho University, Tokyo, Japan; and Department of Biomedical Engineering (K.M.), School of Allied Health Sciences, Kitasato University, Kanagawa, Japan
| | - Kiyoshi Mabuchi
- Department of Ophthalmology (H.I., K.M., T.I., Y.O., T.S., Y.H.), Faculty of Medicine, Toho University, Tokyo, Japan; and Department of Biomedical Engineering (K.M.), School of Allied Health Sciences, Kitasato University, Kanagawa, Japan
| | - Takashi Itokawa
- Department of Ophthalmology (H.I., K.M., T.I., Y.O., T.S., Y.H.), Faculty of Medicine, Toho University, Tokyo, Japan; and Department of Biomedical Engineering (K.M.), School of Allied Health Sciences, Kitasato University, Kanagawa, Japan
| | - Yukinobu Okajima
- Department of Ophthalmology (H.I., K.M., T.I., Y.O., T.S., Y.H.), Faculty of Medicine, Toho University, Tokyo, Japan; and Department of Biomedical Engineering (K.M.), School of Allied Health Sciences, Kitasato University, Kanagawa, Japan
| | - Takashi Suzuki
- Department of Ophthalmology (H.I., K.M., T.I., Y.O., T.S., Y.H.), Faculty of Medicine, Toho University, Tokyo, Japan; and Department of Biomedical Engineering (K.M.), School of Allied Health Sciences, Kitasato University, Kanagawa, Japan
| | - Yuichi Hori
- Department of Ophthalmology (H.I., K.M., T.I., Y.O., T.S., Y.H.), Faculty of Medicine, Toho University, Tokyo, Japan; and Department of Biomedical Engineering (K.M.), School of Allied Health Sciences, Kitasato University, Kanagawa, Japan
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Fasanello DC, Su J, Deng S, Yin R, Colville MJ, Berenson JM, Kelly CM, Freer H, Rollins A, Wagner B, Rivas F, Hall AR, Rahbar E, DeAngelis PL, Paszek MJ, Reesink HL. Hyaluronic acid synthesis, degradation, and crosslinking in equine osteoarthritis: TNF-α-TSG-6-mediated HC-HA formation. Arthritis Res Ther 2021; 23:218. [PMID: 34416923 PMCID: PMC8377964 DOI: 10.1186/s13075-021-02588-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 07/22/2021] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND TNF-α-stimulated gene 6 (TSG-6) protein, a TNF-α-responsive hyaladherin, possesses enzymatic activity that can catalyze covalent crosslinks of the polysaccharide hyaluronic acid (HA) to another protein to form heavy chain-hyaluronic acid (HC-HA) complexes in pathological conditions such as osteoarthritis (OA). Here, we examined HA synthase and inflammatory gene expression; synovial fluid HA, TNF-α, and viscosity; and TSG-6-mediated HC-HA complex formation in an equine OA model. The objectives of this study were to (1) evaluate the TNF-α-TSG-6-HC-HA signaling pathway across multiple joint tissues, including synovial membrane, cartilage, and synovial fluid, and (2) determine the impact of OA on synovial fluid composition and biophysical properties. METHODS HA and inflammatory cytokine concentrations (TNF-α, IL-1β, CCL2, 3, 5, and 11) were analyzed in synovial fluid from 63 OA and 25 control joints, and HA synthase (HAS1-3), TSG-6, and hyaluronan-degrading enzyme (HYAL2, HEXA) gene expression was measured in synovial membrane and cartilage. HA molecular weight (MW) distributions were determined using agarose gel electrophoresis and solid-state nanopore measurements, and HC-HA complex formation was detected via immunoblotting and immunofluorescence. SEC-MALS was used to evaluate TSG-6-mediated HA crosslinking, and synovial fluid and HA solution viscosities were analyzed using multiple particle-tracking microrheology and microfluidic measurements, respectively. RESULTS TNF-α concentrations were greater in OA synovial fluid, and TSG6 expression was upregulated in OA synovial membrane and cartilage. TSG-6-mediated HC-HA complex formation was greater in OA synovial fluid and tissues than controls, and HC-HA was localized to both synovial membrane and superficial zone chondrocytes in OA joints. SEC-MALS demonstrated macromolecular aggregation of low MW HA in the presence of TSG-6 and inter-α-inhibitor with concurrent increases in viscosity. CONCLUSIONS Synovial fluid TNF-α concentrations, synovial membrane and cartilage TSG6 gene expression, and HC-HA complex formation were increased in equine OA. Despite the ability of TSG-6 to induce macromolecular aggregation of low MW HA with resultant increases in the viscosity of low MW HA solutions in vitro, HA concentration was the primary determinant of synovial fluid viscosity rather than HA MW or HC-HA crosslinking. The TNF-α-TSG-6-HC-HA pathway may represent a potential therapeutic target in OA.
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Affiliation(s)
- Diana C. Fasanello
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY USA
| | - Jin Su
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY USA
| | - Siyu Deng
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY USA
| | - Rose Yin
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY USA
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY USA
| | - Marshall J. Colville
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY USA
| | - Joshua M. Berenson
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY USA
| | - Carolyn M. Kelly
- Department of Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca, NY USA
| | - Heather Freer
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY USA
| | - Alicia Rollins
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY USA
| | - Bettina Wagner
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY USA
| | - Felipe Rivas
- Virginia Tech-Wake Forest University School of Biomedical Engineering and Sciences, Wake Forest School of Medicine, Winston-Salem, NC USA
| | - Adam R. Hall
- Virginia Tech-Wake Forest University School of Biomedical Engineering and Sciences, Wake Forest School of Medicine, Winston-Salem, NC USA
| | - Elaheh Rahbar
- Virginia Tech-Wake Forest University School of Biomedical Engineering and Sciences, Wake Forest School of Medicine, Winston-Salem, NC USA
| | - Paul L. DeAngelis
- Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK USA
| | - Matthew J. Paszek
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY USA
| | - Heidi L. Reesink
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY USA
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Evaluation of In Vitro Wettability of Soft Contact Lenses Using Tear Supplements. Eye Contact Lens 2021; 47:244-248. [PMID: 32443004 DOI: 10.1097/icl.0000000000000698] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/14/2020] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To evaluate the interaction between tear supplements and soft contact lenses (SCLs), we measured the contact angles (CAs) on the SCLs using commercially available tear supplements. METHODS We used four daily disposable conventional hydrogel lenses (etafilcon A, etafilcon A+ polyvinylpyrrolidone, nelfilcon A, and omafilcon A containing 2-methacryloyloxyethyl phosphorylcholine [MPC]) and four silicone hydrogel lenses (narafilcon A, senofilcon A, delefilcon A, and stenfilcon A). The CAs on the SCLs were measured using a sessile drop technique and four different types of sessile drops, including saline, artificial tears, lubricants containing 2-MPC (MPC solution), and 0.1% hyaluronate acid (HA). RESULTS The CA values associated with the silicone hydrogel lenses were significantly (P<0.001) lower than those associated with the conventional hydrogel lenses with all four solutions. The mean CA of 0.1% HA was significantly (P<0.01) higher than that of saline. The mean CA of the MPC solution was significantly (P<0.01) lower than that of saline with the conventional hydrogel lenses but significantly (P<0.05) higher than that of saline with the silicone hydrogel lenses. CONCLUSIONS The CAs associated with the silicone hydrogel SCLs were higher with the use of the MPC solutions and HA in vitro. The measured CAs may depend on ingredient agents, surface treatment of the CLs, and components of the tear supplements.
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Viscosity Measurement Sensor: A Prototype for a Novel Medical Diagnostic Method Based on Quartz Crystal Resonator. SENSORS 2021; 21:s21082743. [PMID: 33924605 PMCID: PMC8070455 DOI: 10.3390/s21082743] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/08/2021] [Accepted: 04/09/2021] [Indexed: 12/26/2022]
Abstract
Viscosity variation in human fluids, such as Synovial Fluid (SF) or Cerebrospinal Fluid (CSF), can be used as a diagnostic factor; however, the sample volume obtained for analysis is usually small, making it difficult to measure its viscosity. On the other hand, Quartz Crystal Resonators (QCR) have been used widely in sensing applications due to their accuracy, cost, and size. This work provides the design and validation of a new viscosity measurement system based on quartz crystal resonators for low volume fluids, leading to the development of a sensor called “ViSQCT” as a prototype for a new medical diagnostic tool. The proposed method is based on measuring the resonance frequency at the crystal’s maximum conductance point through a frequency sweep, where crystals with 10 MHz fundamental resonance frequency were used. For validation purposes, artificial fluids were developed to simulate SFs and CFs in healthy and pathological conditions as experiment phantoms. A commercial QCR based system was also used for validation since its methodology differs from ours. A conventional rotational viscometer was used as a reference for calibration purposes. ViSQCT demonstrates the capability to measure the sample’s viscosity differentiation between healthy and pathological fluid phantoms and shows that it can be used as a basis for a diagnostic method of several pathologies related to the studied biological fluids. However, some performance differences between both QCR-based systems compared to the reference system deserves further investigation.
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Fort A, Panzardi E, Vignoli V, Tani M, Landi E, Mugnaini M, Vaccarella P. An Adaptive Measurement System for the Simultaneous Evaluation of Frequency Shift and Series Resistance of QCM in Liquid. SENSORS 2021; 21:s21030678. [PMID: 33498354 PMCID: PMC7864047 DOI: 10.3390/s21030678] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/14/2021] [Accepted: 01/16/2021] [Indexed: 11/23/2022]
Abstract
In this paper, a novel measurement system based on Quartz Crystal Microbalances is presented. The proposed solution was conceived specifically to overcome the measurement problems related to Quartz Crystal Microbalance (QCM) applications in dielectric liquids where the Q-factor of the resonant system is severely reduced with respect to in-gas applications. The QCM is placed in a Meacham oscillator embedding an amplifier with adjustable gain, an automatic strategy for gain tuning allows for maintaining the oscillator frequency close to the series resonance frequency of the quartz, which is related in a simple way with the physical parameters of interest. The proposed system can be used to monitor simultaneously both the series resonant frequency and the equivalent electromechanical resistance of the quartz. The feasibility and the performance of the proposed method are proven by means of measurements obtained with a prototype based on a 10-MHz AT-cut quartz.
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