Quantum dots as a fluorescent labeling tool for live-cell imaging of Leptospira.

Leptospirosis is a global public health problem caused by Gram-negative pathogenic bacteria belonging to the genus Leptospira. The disease is transmitted through the urine of infected animals, which contaminates water and soil, leading to the infection of other animals and humans. Currently, several approaches exist to detect these bacteria; however, a new sensitive method for the live-cell imaging of Leptospira is required. In this study, we report the green synthesis of cadmium telluride quantum dots (CdTe QDs) which are unique fluorescent nanocrystals with a high fluorescence quantum yield capable of modifying cell surfaces and are biocompatible with cells. The fabrication of QDs with concanavalin A (ConA), a carbohydrate-binding lectin and known biological probe for Gram-negative bacteria, produced ConA-QDs which can effectively bind on Leptospira and exhibit strong fluorescence under simple fluorescence microscopy, allowing the live-cell imaging of the bacteria. Overall, we performed the simple synthesis of ConA-QDs and demonstrated their potential use as versatile fluorescent probes for the live-cell imaging of Leptospira. This technique could be further applied to track leptospiral cells and study the infection mechanism, contributing to a more thorough understanding of leptospirosis and how to control it in the future.

Ultrafine Graphite Scrap and Carbon Blocks Prepared by High-Solid-Loading Bead Milling and Conventional Ball Milling: A Comparative Assessment.

A comparison between the physical characteristics of graphite ultrafine particles and the properties of graphite blocks prepared from graphite scrap using bead and conventional ball milling techniques is presented. Industrial-scale bead milling was used to prepare graphite scrap with an initial particle size d50 of 24 µm in the ultrafine range of <10 µm. Bead milling can significantly reduce the production time of ultrafine graphite from graphite scrap from 72 h by ball milling to 10 min. Ultrafine graphite scrap prepared from both ball milling and bead milling yields particles with a similar morphology, with a minor difference in crystalline size La and stacking height Lc observed. Carbon blocks were fabricated from both techniques, yielding carbon blocks with an almost identical microstructure and block density. Blocks from bead milling have slightly higher flexural strength as well as comparable hardness and resistivity. The block's flexural strength, hardness, and resistivity were 68.37 MPa, 99, and 36.9 µΩ·m, respectively, in a bead-milled carbon block and 61.86 MPa, 95.5, and 38.6 µΩ·m, respectively, for a ball-milled carbon block. Bead milling can be applied for the preparation of ultrafine graphite particles and graphite blocks with production that is 9 times faster for the same ultrafine graphite particle output and final product quality.

Improvement of Ball Mill Performance in Recycled Ultrafine Graphite Waste Production for Carbon Block Applications.

A carbon block is a carbonaceous material used in various applications such as bearings, mechanical seals, and electrical brushes. This work aims to fabricate carbon blocks from industrial graphite waste, a residue from the cutting and tooling process of graphite block production. The ball milling process was used to fabricate ultrafine graphite waste to enhance the packing of carbon blocks. The milling performance was profoundly affected by dispersing agents in which sodium dodecyl sulfate (SDS), lignosulfonate (LS), and mixed dispersant (LS-SDS) were applied. The results showed that LS-SDS had the best milling performance, the greatest grinding index, and a flowable slurry, indicating the potentiality of this formulation for the environmentally friendly manufacture of ultrafine graphite waste. Carbon blocks were prepared from oven-dried ultrafine graphite waste, which was mixed with amorphous carbon and pitch. This carbon mixture was formed a block by compaction before carbonization and impregnation. The density of the fabricated carbon blocks increased from 1.76 to 1.83 g/cm3 after impregnation along with the increase in hardness, flexural strength, and reduction in electrical resistivity from 83, 62 MPa, and 40 µΩ m to 88, 81 MPa, and 39 µΩ m, respectively. The physical properties of carbon blocks prepared from ultrafine graphite waste were comparable to the properties of typical pristine carbon products.

Application of QuantiFERON ELISA for Detection of Interferon-Gamma Autoantibodies in Adult-Onset Immunodeficiency Syndrome.

OBJECTIVE: Patients who develop interferon-gamma autoantibodies (IFN-ɤ autoAbs) in adult-onset immunodeficiency (AOID) syndrome are more likely to develop opportunistic and recurrent intracellular infections. The assay to detect IFN-ɤ autoAbs is essential for the diagnosis and therapeutic monitoring of AOID syndrome. Therefore, this study applied the QuantiFERON assay for the detection of IFN-ɤ autoAbs. METHODS: Serum from patients with AOID syndrome (n = 19) and serum from healthy patients (n = 20) was collected and applied using 2 neutralizing platforms of enzyme-linked immunosorbent assay (ELISA) kits (the BD ELISA and the QuantiFERON ELISA) for IFN-ɤ autoAbs detection. RESULTS: The pooled serum from patients with AOID syndrome showed >50% inhibition at 1:5000 dilution (positive), whereas the pooled serum from healthy patients showed <50% inhibition at 1:5000 dilution (negative) according to the neutralizing QuantiFERON ELISA. Each specimen showed the same result according to both the neutralizing BD ELISA and the neutralizing QuantiFERON ELISA. Moreover, the patient serum showed a variation in titer ranging from 1:5000 to >1:5,000,000 according to the neutralizing QuantiFERON ELISA. CONCLUSION: The QuantiFERON ELISA kit could be applied for the detection of IFN-ɤ autoAbs for the diagnosis and therapeutic monitoring of AOID syndrome.

Effect of surface chemistry-modified polycaprolactone scaffolds on osteogenic differentiation of stem cells from human exfoliated deciduous teeth.

The aim of this study was to investigate the effect of surface modification of a polycaprolactone scaffold on promoting osteogenic differentiation of stem cells from human exfoliated deciduous teeth. Four different polycaprolactone scaffold were evaluated: untreated; coated with hyaluronic acid; coated with gelatin; and coated with hyaluronic acid and then with gelatin. The resulting scaffolds were characterized using scanning electron microscopy and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). Human stem cells were cultured on the modified scaffolds placed in osteogenic differentiation medium. During culture, the osteogenic potential of the stem cells was examined by evaluating alkaline phosphatase activity and staining intensity, expression of osteoblastic-specific genes, and matrix mineralization. Scanning electron microscopy and ATR-FTIR confirmed productive biomacromolecular surface treatment of the polycaprolactone scaffold. All scaffolds permitted differentiation of stem cells into osteoblastic cells, but the gelatin-coated polycaprolactone scaffold facilitated osteogenesis of a larger number of stem cells than the untreated and the hyaluronic acid-coated scaffolds. We demonstrate that gelatin is an appropriate macromolecule for modifying the surface of an electrospun polycaprolactone fibre scaffold that is used subsequently in bone tissue engineering applications.

Colorimetric reverse transcription loop-mediated isothermal amplification (RT-LAMP) as a visual diagnostic platform for the detection of the emerging coronavirus SARS-CoV-2.

COVID-19, caused by the infection of SARS-CoV-2, has emerged as a rapidly spreading infection. The disease has now reached the level of a global pandemic and as a result a more rapid and simple detection method is imperative to curb the spread of the virus. We aimed to develop a visual diagnostic platform for SARS-CoV-2 based on colorimetric RT-LAMP with levels of sensitivity and specificity comparable to that of commercial qRT-PCR assays. In this work, the primers were designed to target a conserved region of the RNA-dependent RNA polymerase gene (RdRp). The assay was characterized for its sensitivity and specificity, and validated with clinical specimens collected in Thailand. The developed colorimetric RT-LAMP assay could amplify the target gene and enabled visual interpretation in 60 min at 65 °C. No cross-reactivity with six other common human respiratory viruses (influenza A virus subtypes H1 and H3, influenza B virus, respiratory syncytial virus types A and B, and human metapneumovirus) and five other human coronaviruses (MERS-CoV, HKU-1, OC43, 229E and NL63) was observed. The limit of detection was 25 copies per reaction when evaluated with contrived specimens. However, the detection rate at this concentration fell to 95.8% when the incubation time was reduced from 60 to 30 min. The diagnostic performance of the developed RT-LAMP assay was evaluated in 2120 clinical specimens and compared with the commercial qRT-PCR. The results revealed high sensitivity and specificity of 95.74% and 99.95%, respectively. The overall accuracy of the RT-LAMP assay was determined to be 99.86%. In summary, our results indicate that the developed colorimetric RT-LAMP provides a simple, sensitive and reliable approach for the detection of SARS-CoV-2 in clinical samples, implying its beneficial use as a diagnostic platform for COVID-19 screening.

Impact of household vinegar on calculus removal and mechanical properties of orthodontic resin.

PURPOSE: This study evaluated calculus removal efficacy of household vinegar and its effect on autopolymerizing orthodontic resin following repeated immersion. METHODS: A total of 72 sectioned specimens of orthodontic retainers with calculus deposits following cleaning with the help of immersion in vinegar of different dilutions between 12.5% and 100%, tap water, effervescent tablets, and mechanical debridement were digitally analyzed. Changes in Ca and Fe ions in vinegar were assessed by atomic emission spectroscopy (AES). For mechanical testing, autopolymerizing polymethyl methacrylate (PMMA) samples were similarly grouped and immersed for 78 cycles and their flexural strength and hardness measured. Fourier-transform infrared spectroscopy (FTIR) was performed to evaluate changes in their chemical composition. One-way analysis of variance (ANOVA) and Tukey's test were used to analyze the differences in the mean flexural strength and hardness between the groups (p ≤ 0.05). RESULTS: A minimum immersion of 2 h in 25% vinegar solution combined with brushing attained efficiency of 74.13 ± 22% calculus removal. Whereas, tap water and effervescent tablets had 15% and 49% efficiency, respectively. AES results showed diffusion of Ca ions from calculus into the vinegar solution as a plausible mechanism for its structural weakening and removal. Results of mechanical testing showed that undiluted vinegar solution affected the flexural strength of PMMA and this effect was significantly different from that of the effervescent tablets and the remaining vinegar concentrations. There was no significant difference in hardness between the groups. The FTIR showed no changes in the chemical composition of PMMA samples following repeated immersions. CONCLUSION: Vinegar can be useful in the removal of calculus from dental appliances but should be used in diluted forms to minimize side effects.

Rh blood phenotyping (D, E, e, C, c) microarrays using multichannel surface plasmon resonance imaging.

The application of Surface Plasmon Resonance Imaging (SPRi) for the detection of transmembrane antigen of the Rhesus (Rh) blood group system is demonstrated. Clinically significant Rh blood group system antigens, including D, C, E, c, and e, can be simultaneously identified via solid phase immobilization assay, which offers significant time savings and assay simplification. Red blood cells (RBCs) flowed through the micro-channel, where a suitable condition for Rh blood group detection was an RBC dilution of 1:10 with a stop-flow condition. Stop flow showed an improvement in specific binding compared to continuous flow. Rh antigens required a longer incubation time to react with the immobilized antibody than A and B antigens due to the difference in antigen type and their location on the RBC. The interaction between the immobilized antibodies and their specific antigenic counterpart on the RBC showed a significant difference in RBC removal behavior using shear flow, measured from the decay of the SPR signal. The strength of the interaction between the immobilized antibody and RBC antigen was determined from the minimum wall shear stress required to start the decay process in the SPR signal. For a given range of immobilized antibody surface densities, the Rh antigen possesses a stronger interaction than A, B, and AB antigens. Identification of 82 samples of ABO and Rh blood groups using SPRi showed good agreement with the standard micro-column agglutination technique. A wider coverage of antigenic recognition for RBC when using the solid phase immobilization assay was demonstrated for the RBC with the antigenic site located on the transmembrane protein of the clinically significant Rh antigen. Given the level of accuracy and precision, the technique showed potential for the detection of the Rh minor blood group system.

Influence of the cross-linking agent on mechanical properties of PMMA powder with compromised particle morphology.

OBJECTIVE: To investigate the effect of a cross-linking agent on the mechanical properties of self-cured orthodontic acrylic resin using PMMA powder (CPM-PMMA) with a compromised microstructure. MATERIALS AND METHODS: The mechanical properties of three sample groups were investigated in this study: CPM-PMMA, orthocryl and orthoplast. CPM-PMMA powder was prepared by suspension polymerization. It was mixed with a commercially available liquid (orthocryl) to yield a test specimen and to compare its flexural properties and Vicker hardness with the two commercial products. Molecular weight and particle size distribution of all groups were examined. Particle morphology was observed using scanning electron microscopy (SEM) and optical microscopy (OM). RESULTS: The average molecular weight of the CPM-PMMA powder was similar to that of the industrial products. Its particle size distribution was narrow and limited to large sizes (91.1-149µm). SEM and OM presented the compromise particle morphology. However, the flexural properties and Vicker hardness of CPM-PMMA powder mixed with orthocryl liquid showed no significant difference compared with orthocryl sample group. In addition, the CPM-PMMA had higher flexural properties than the orthoplast samples. CONCLUSIONS: Although the CPM-PMMA powder presented a compromised particle morphology and narrow particle size distribution, when mixed with orthocryl liquid, the cured resin produced acceptable mechanical properties due to the large amount of cross-linking agent. This result could indicate that the mechanical properties of self-cured acrylic resins are mainly dependent on the amount of cross-linking agent in the liquid component.

Surface plasmon resonance imaging for ABH antigen detection on red blood cells and in saliva: secretor status-related ABO subgroup identification.

Low antigenic expression of ABO subgroup system on red blood cell (RBC) is cause of discrepancy between forward and reverse blood typing in the standard agglutination technique. Neutralization agglutination is employed for verification of the detection of ABH substances in saliva. However, the neutralization technique is complicated, time-consuming and requires expertise. To overcome these drawbacks, surface plasmon resonance (SPR) imaging was developed for ABH antigen detection on RBCs and in saliva. An antibody array was designed to classify the ABO subgroups by anti-A, anti-B, and anti-H antibodies; the array was immobilized on a carboxymethyl-dextran sensor-surface. RBCs and saliva specimens from sixty-four donors were analysed by passing them over the antibody array, where the secretor status and blood group could be simultaneously identified. Consequently, the immobilized antibodies could specifically and quantitatively detect the ABH antigen on RBCs. Using the direct assay, the SPR signal of saliva detection was weaker than that of RBC detection. However, a sandwich assay with a mixture of anti-A, anti-B, and anti-H antibodies could efficiently enhance the signal. The sensor chip provided high specificity (cut-off at 100 to 175 micro refractive index units) and high precision at 0.06%-4.9% CV. The blood group results of the sixty-four donor specimens obtained by SPR agreed with the standard agglutination test with 100% accuracy. SPR could indicate different ABH antigen densities on the RBCs and nearly the same amounts of ABH substances in the saliva of strong and weak subgroups. Finally, we also demonstrated reduced assay time and fewer complications with the SPR imaging platform compared to the neutralization technique.

SiO2-nanocomposite film coating of CAD/CAM composite resin blocks improves surface hardness and reduces susceptibility to bacterial adhesion.

Composite resin blocks for computer-aided design/computer-aided manufacturing (CAD/CAM) applications have recently become available. However, CAD/CAM composite resins have lower wear resistance and accumulate more plaque than CAD/CAM ceramic materials. We assessed the effects of SiO2-nanocomposite film coating of four types of CAD/CAM composite resin blocks: Cerasmart, Katana Avencia block, Lava Ultimate, and Block HC on surface hardness and bacterial attachment. All composite blocks with coating demonstrated significantly greater Vickers hardness, reduced surface roughness, and greater hydrophobicity than those without coating. Adhesion of Streptococcus mutans to the coated specimens was significantly less than those for the uncoated specimens. These reduced levels of bacterial adherence on the coated surface were still evident after treatment with saliva. Surface modification by SiO2-nanocomposite film coating has potential to improve wear resistance and susceptibility to plaque accumulation of CAD/CAM composite resin restorations.

Colorimetric Detection by Gold Nanoparticle DNA Probes for Miltenberger Series (GP.Mur, GP.Hop, and GP.Bun) Identification.

BACKGROUND: Miltenberger (Mi) series are the collective glycophorin hybrids in the MNS blood group system. Mi series are composed of several subtypes, for examples, GP.Mur, GP.Hop, and GP.Bun. The incompatibility of Mi series blood transfusion poses the risk of hemolysis. Due to the lack of standard antibodies for Mi series blood typing, colorimetric gold nanoparticle (AuNP) DNA probes were therefore explored for Mi series identification. METHODS: AuNPs were synthesized and conjugated to an RvB (test) probe and an RvA2 (control) probe. Each of the AuNP DNA probes was tested against the amplified products of Mi(+) (GP.Mur/Hop/Bun), Mi(-), and the blank (no amplified product). The change in color was observed by visual inspection and UV-Vis spectroscopy. RESULTS: The amplified product of the Mi(+) sample retained the color on both probes (test+/control+). The amplified product of the Mi(-) sample retained the color only on the control probe (test-/control+) and the amplified product of the blank turned clear on both probes (test-/control-). The results by optical density absorbance measurement were concordant with the results by visual inspection. Both probes were validated with the amplified products of the ten Mi(+) and ten Mi(-) samples. All of the samples were correctly identified. CONCLUSION: AuNP DNA probes (RvB and RvA2) could be applied to distinguish the amplified products of Mi(+), Mi(-), and the blank by visual inspection and/or OD absorbance measurement.

Hemoculture and Direct Sputum Detection of mecA-Mediated Methicillin-Resistant Staphylococcus aureus by Loop-Mediated Isothermal Amplification in Combination With a Lateral-Flow Dipstick.

This study reports loop-mediated isothermal amplification (LAMP) for rapid detection of methicillin-resistant Staphylococcus aureus from direct clinical specimens. Four primers including outer and inner primers were specifically designed on the two target sequences-femB to identify S. aureus and mecA to identify antibiotic-resistant gene. Reference strains including various species of gram-positive/gram-negative isolates were used to evaluate and optimize LAMP assays. The optimum LAMP condition was found at 63°C within 70 min assay time (include hybridization with FITC probe for 5 min and further 5 min for reading the results on the lateral flow dipstick). The detection limits of LAMP for mecA was 10 pg of total DNA or 100 CFU/ml. The LAMP assays were applied to a total of 155 samples of direct DNA extraction from sputum and hemoculture bottles. The sensitivity of LAMP for mecA detection in sputum and hemoculture bottles was 93.3% (28/30) and 100% (52/52), respectively. In conclusion, LAMP assay is an alternative technique for rapid detection of MRSA infection with a technical simplicity and cost-effective method in a routine diagnostic laboratory.

Application of Long-Range Surface Plasmon Resonance for ABO Blood Typing.

In this study, we demonstrate a long-range surface plasmon resonance (LR-SPR) biosensor for the detection of whole cell by captured antigens A and B on the surface of red blood cells (RBCs) as a model. The LR-SPR sensor chip consists of high-refractive index glass, a Cytop film layer, and a thin gold (Au) film, which makes the evanescent field intensity and the penetration depth longer than conventional SPR. Therefore, the LR-SPR biosensor has improved capability for detecting large analytes, such as RBCs. The antibodies specific to blood group A and group B (Anti-A and Anti-B) are covalently immobilized on a grafting self-assembled monolayer (SAM)/Au surface on the biosensor. For blood typing, RBC samples can be detected by the LR-SPR biosensor through a change in the refractive index. We determined that the results of blood typing using the LR-SPR biosensor are consistent with the results obtained from the agglutination test. We obtained the lowest detection limits of 1.58 × 105 cells/ml for RBC-A and 3.83 × 105 cells/ml for RBC-B, indicating that the LR-SPR chip has a higher sensitivity than conventional SPR biosensors (3.3 × 108 cells/ml). The surface of the biosensor can be efficiently regenerated using 20 mM NaOH. In summary, as the LR-SPR technique is sensitive and has a simple experimental setup, it can easily be applied for ABO blood group typing.

SPR-DNA array for detection of methicillin-resistant Staphylococcus aureus (MRSA) in combination with loop-mediated isothermal amplification.

In this study, we evaluated surface plasmon resonance imaging (SPR imaging) as a DNA biosensor for the detection of methicillin-resistant Staphylococcus aureus (MRSA) which is one of the most common causes of nosocomial infections. The DNA sample were collected from clinical specimens, including sputum and blood hemoculture were undergone LAMP amplification for 0.18 kbp and 0.23 kbp DNA fragments of femB and mecA genes, respectively. The self-assembled monolayer surface (SAMs) was used for immobilized streptavidin-biotinylated probes on the sensor surface for the detection of LAMP amplicons from MRSA. Both LAMP amplicons were simultaneously hybridized with ssDNA probes immobilized onto a bio-functionalized surface to detect specific targets in the multiplex DNA array platform. In addition, the sensor surface could be regenerated allowing at least five cycles of use with a shortened assay time. The detection limit of LAMP-SPR sensing was 10 copies/µl and LAMP-SPR sensing system showed a good selectivity toward the MRSA.

Wear resistance of a modified polymethyl methacrylate artificial tooth compared to five commercially available artificial tooth materials.

STATEMENT OF PROBLEM: Wear resistance is a limitation of artificial denture teeth. Improving the wear resistance of conventional artificial denture teeth is of value to prosthodontic patients. PURPOSE: The purpose of this in vitro study was to evaluate the wear resistance and hardness of modified polymethyl methacrylate artificial denture teeth compared to 5 commercially available artificial tooth materials. MATERIAL AND METHODS: This study evaluated 180 artificial denture teeth (6 groups) that included 3 groups of conventional artificial teeth (MajorDent, Cosmo HXL, and Gnathostar), 2 groups of composite resin artificial teeth (Endura and SR Orthosit PE), and 1 group of modified surface artificial teeth. The flattened buccal surface of each tooth (n=15) was prepared for investigation with the Vickers hardness test and the elucidate wear test (n=15) by using a brushing machine. Each group was loaded for 18,000 cycles, at 2 N, and 150 rpm. The wear value was identified with a profilometer. The data were statistically analyzed by using 1-way ANOVA and post hoc Turkey honestly significant difference tests (α=.001). The tribologies were observed under a scanning electron microscope, and the cytotoxicities were evaluated by MTT assay. RESULTS: The Vickers hardnesses ranged from 28.48 to 39.36. The wear depths and worn surface area values ranged from 1.12 to 10.79 µm and from 6.74 to 161.95 µm(2). The data revealed that the modified artificial denture teeth were significantly harder and exhibited significantly higher wear resistance than did the conventional artificial teeth (P<.001). The scanning electron microscopic images revealed cross sections of the conventional artificial denture teeth with intensively worn surface areas after brushing. The cytotoxicity test revealed 97.85% cell viability, which indicates the nontoxicity of the modified surface of this material. CONCLUSIONS: Within the limitations of this study, the polymethyl methacrylate modified surface artificial denture teeth was not significantly different from that of the composite resin artificial denture teeth, with the exceptions that the surface was harder and more wear resistant.

Evaluation of agglutination strength by a flow-induced cell movement assay based surface plasmon resonance (SPR) technique.

A flow-induced cell movement assay combined with a surface plasmon resonance (SPR) technique was developed to quantify the agglutination strength, derived from the standard tube-agglutination test. Red blood cells (RBCs), based on the ABO blood group system, were specifically captured by anti-A and/or anti-B antibodies immobilized on a sensor surface. The agglutination strength corresponds to the amount of antigen-antibody interactions or the strength of RBC adhesion. Under a shear flow, the adherent RBCs were forced to move out of the region of interest with different average cell velocities (vc) depending upon the adhesion strength and wall shear stress (WSS). That is, a higher adhesion strength (higher agglutination strength) or lower WSS represents a lower vc or vice versa. In this work, the agglutination strength was derived from the vc that was calculated from the time derivative of the relative SPR signal by using a simple model of cell movement response, whose validity was verified. The vc values of different samples were correlated with their agglutination strengths at a given WSS and antibody surface density. The vc decreased as the agglutination strength increased, which can be considered as a linear regression. The coefficient of variation of the calculated vc decreased to 0.1 as vc increased to 30 µm min(-1). The sensitivity of this assay can be controlled by optimizing the antibody surface density or the WSS. This assay has the capability to resolve the antigen density of A1 and B RBCs from that of A1B RBCs.

The effects of silane-SiO2 nanocomposite films on Candida albicans adhesion and the surface and physical properties of acrylic resin denture base material.

STATEMENT OF PROBLEM: Polysiloxane has been used as a coupling material in restorative dental materials for several decades. However, few studies are available on the application of polysiloxane in other dental prosthesis functions. PURPOSE: The purpose of this study was to investigate the effects of silane-SiO2 nanocomposite films on Candida albicans adhesion and the surface and physical properties of acrylic resin denture base materials. MATERIAL AND METHODS: Specimens were separated into 2 groups, uncoated and coated. They were coated with a film by using the dip-coating method. Specimens were incubated with Candida albicans 10(7) cells/mL for 1 hour, and the adherent cells were counted under an optical microscope. The following surface properties were measured: surface chemical composition with Fourier-transform infrared spectrometry, surface roughness with a surface profiler, surface energy with the sessile drop method, and surface hardness with a microhardness tester. The physical properties, including water sorption, water solubility, ultimate flexural strength, and flexural modulus, were evaluated according to International Organization for Standardization 20795-1 requirements. The adhesion of Candida albicans and the surface properties of the specimens were investigated after cleaning with effervescent tablets and brushing. An MTT assay was used to evaluate the coated specimens. The results were statistically analyzed with the Mann-Whitney U test (α=.05). RESULTS: A significant reduction in Candida albicans adhesion (P=.002) was observed before cleaning. In addition, the surface energy was comparable (P=.100), the surface hardness increased significantly (P=.008), and the surface roughness remained unchanged (P=.310). After cleaning with effervescent tablets, a significant decrease in Candida albicans adhesion (P=.002) and in surface roughness (P=.008) was observed; however, similar surface energies were measured (P=.100). After cleaning with a toothbrush, the adhesion of Candida albicans was significantly higher on the coated specimen than on the uncoated specimen (P=.004). The surface roughness values were significantly different (P=.008), and the surface energies could not be determined. The coated specimen had a silicon-oxygen-silicon peak instead of an ester bond in the polymethyl methacrylate structure. The coating film reduced the water sorption (P=.008) and water solubility (P=.032), and increased the ultimate flexural strength (P=.008) and flexural modulus (P=.032) of the specimen. The coated specimen also had satisfactory toxicity results. CONCLUSIONS: Reduced Candida albicans adhesion was observed on the coated specimens. The polymeric film did not change the surface roughness of the acrylic resin specimen; however, it did slightly reduce the surface energy. The physical properties of the acrylic resin did not decrease after it was coated with the film.

ABO blood-typing using an antibody array technique based on surface plasmon resonance imaging.

In this study, readily available antibodies that are used in standard agglutination tests were evaluated for their use in ABO blood typing by a surface plasmon resonance imaging (SPR imaging) technique. Five groups of antibodies, including mixed clones of anti-A, anti-B, and anti-AB, and single clones of anti-A and anti-B, were used to construct the five-line detection arrays using a multichannel flow cell in the SPR imager. The red blood cell (RBC) samples were applied to a multichannel flow cell that was orthogonal to the detection line arrays for blood group typing. We found that the blood samples were correctly grouped in less than 12 min by the SPR imaging technique, and the results were consistent with those of the standard agglutination technique for all 60 samples. We found that mixed clones of antibodies provided 33%-68% greater change in the SPR signal than the single-clone antibodies. Applying the SPR imaging technique using readily available antibodies may reduce the costs of the antibodies, shorten the measurement time, and increase the throughput.