The Surface Property of Hydroxyapatite: Sensing with Quartz Crystal Microbalance

Hydroxyapatite (HAp) sensor, available for quartz crystal microbalance with dissipation (QCM-D) technique, has been fabricated by an electrophoretic deposition method. The method of re-usability of the sensor after adsorption of fibrinogen and the biological apatite (BAp) growth on the sensor with and without the adsorption of feral bovine serum (FBS) from 1.5 simulated body fluid were investigated. The re-usability of the sensor, cleaning with the combination of ammonia and hydrogen peroxide mixture and UV/ozone treatment, achieved ten times reuses. BAp was grown on the HAp surface but not on the gold surface at 37.5 oC for 40 hours. The viscoelastic property (DD/Df value) of the BAp layer on the HAp sensor showed harder than that of the protein adsorption films from FBS. The amount of the BAp grown on the HAp sensor adsorbed FBS is lower than that on the HAp sensor. The adsorption of FBS proteins on the HAp surface strongly inhibited the BAp growth.

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Quantitative Analysis of Apatite Formation on Titanium and Zirconia in a Simulated Body Fluid Solution Using the Quartz Crystal Microbalance Method

Advances in Materials Science and Engineering ◽

10.1155/2017/7928379 ◽

2017 ◽

Vol 2017 ◽

pp. 1-9 ◽

Cited By ~ 7

Author(s):

Eiji Yoshida ◽

Tohru Hayakawa

Keyword(s):

Quantitative Analysis ◽

Simulated Body Fluid ◽

Quartz Crystal Microbalance ◽

Body Fluid ◽

Quartz Crystal ◽

Simulated Body Fluid Solution ◽

Apatite Formation ◽

Fluid Solution ◽

Stabilized Zirconia ◽

Significant Difference

The bone-bonding ability of a material is evaluated by examining apatite formation on its surface in simulated body fluid (SBF). Partially stabilized zirconia (ZrO2) is currently attractive as an alternative to titanium (Ti) implants; however, no quantitative analysis of apatite formation between Ti and ZrO2 in SBF has been reported. In the present study, we quantitatively evaluated apatite formation onto Ti or ZrO2 in SBF using the 27 MHz quartz crystal microbalance method (QCM). In the QCM measurements, apatite formation was detected as a frequency decrease in the Ti or ZrO2 sensor. Frequency decreases were observed at around 1 hour for Ti and at around 2 hours for the ZrO2 sensor after the injection of SBF. This revealed that the Ti sensor showed faster apatite formation than ZrO2. There was no significant difference in the amounts of apatite formation between the Ti and ZrO2 sensors after 24 hours of apatite formation in SBF. In conclusion, the present quantitative study using QCM revealed that apatite formation on the Ti surface in the SBF was obviously faster than that on the ZrO2 surface. Faster apatite formation may predict faster initiation of bone formation on Ti compared with ZrO2.

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Quantitative Assessment of Periodontal Bacteria Using a Cell-Based Immunoassay with Functionalized Quartz Crystal Microbalance

Chemosensors ◽

10.3390/chemosensors9070159 ◽

2021 ◽

Vol 9 (7) ◽

pp. 159

Author(s):

Satit Rodphukdeekul ◽

Miyuki Tabata ◽

Chindanai Ratanaporncharoen ◽

Yasuo Takeuchi ◽

Pakpum Somboon ◽

...

Keyword(s):

Monoclonal Antibody ◽

Quartz Crystal Microbalance ◽

Quantitative Assessment ◽

Quartz Crystal ◽

Dynamic Range ◽

Gold Surface ◽

Enzyme Linked Immunosorbent Assay ◽

Inflammatory Disorder ◽

Label Free ◽

Periodontal Bacteria

Periodontal disease is an inflammatory disorder that is triggered by bacterial plaque and causes the destruction of the tooth-supporting tissues leading to tooth loss. Several bacteria species, including Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, are considered to be associated with severe periodontal conditions. In this study, we demonstrated a quartz crystal microbalance (QCM) immunoassay for quantitative assessment of the periodontal bacteria, A. actinomycetemcomitans. An immunosensor was constructed using a self-assembled monolayer of 11-mercaptoundecanoic acid (11-MUA) on the gold surface of a QCM chip. The 11-MUA layer was evaluated using a cyclic voltammetry technique to determine its mass and packing density. Next, a monoclonal antibody was covalently linked to 11-MUA using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide to act as the biorecognition element. The specificity of the monoclonal antibody was confirmed by an enzyme-linked immunosorbent assay. A calibration curve, for the relationship between the frequency shifts and number of bacteria, was used to calculate the number of A. actinomycetemcomitans bacteria in a test sample. Based on a regression equation, the lower detection limit was 800 cells, with a dynamic range up to 2.32 × 106 cells. Thus, the QCM biosensor in this study provides a sensitive and label-free method for quantitative analysis of periodontal bacteria. The method can be used in various biosensing assays for practical application and routine detection of periodontitis pathogens.

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