Detection of Cartilage Oligomeric Matrix Protein Using a Quartz Crystal Microbalance

Current methods for diagnosing early stage osteoarthritis (OA) based on the magnetic resonance imaging and enzyme-linked immunosorbent assay methods are specific, but require specialized laboratory facilities and highly trained personal to obtain a definitive result. In this work, a user friendly and non-invasive quartz crystal microbalance (QCM) immunosensor method has been developed to detect Cartilage Oligomeric Matrix Protein (COMP) for early stage OA diagnosis. This QCM immunosensor was fabricated to immobilize COMP antibodies utilizing the self-assembled monolayer technique. The surface properties of the immunosensor were characterized by its FTIR and electrochemical impedance spectra (EIS). The feasibility study was based on urine samples obtained from 41 volunteers. Experiments were carried out in a flow system and the reproducibility of the electrodes was evaluated by the impedance measured by EIS. Its potential dynamically monitored the immunoreaction processes and could increase the efficiency and sensitivity of COMP detection in laboratory-cultured preparations and clinical samples. The frequency responses of the QCM immunosensor changed from 6 kHz when testing 50 ng/mL COMP concentration. The linear regression equation of frequency shift and COMP concentration was determined as: y = 0.0872 x + 1.2138 (R2 = 0.9957). The COMP in urine was also determined by both QCM and EIS for comparison. A highly sensitive, user friendly and cost effective analytical method for the early stage OA diagnosis has thus been successfully developed

Surface Plasmon Resonance (SPR) Combined Technology: A Powerful Tool for Investigating Interface Phenomena

Abstract Interface phenomena refer to the phenomena caused by various physical and chemical processes occurring at phase interfaces. These phenomena can include adhesion, friction, lubrication, evaporation, condensation, adsorption, monolayer formation, and other phenomena and are applied in many fields, such as food, papermaking, rubber, material science, energy, and biomedicine. However, traditional detection equipment cannot meet the interface phenomena observation needs because the information detected by techniques such as electrochemistry, spectroscopy, chromatography, and mass spectrometry is limited, as are the sensitivity and minimum detection limit. Surface plasmon resonance (SPR) combined technology is a powerful tool for investigating interface phenomena. This paper reviews all combination technologies of SPR with various conventional detection systems, emphasizing the combination with electrochemistry, Raman spectroscopy, and mass spectrometry. These technologies can observe interface phenomena through SPR and provide redox, molecular structure, functional group change, and other information. Through this information, the reactions on the interface can be made clearer and more controllable, which plays an important role in practical detection. In the future, SPR combined technology will mainly develop toward signal enhancement, light source coupling mode, and sensor chip design, and SPR will be combined with various detection technologies to achieve real‐time in situ detection of interface phenomena

Peptide-based antifouling aptasensor for cardiac troponin I detection by surface plasmon resonance applied in medium sized Myocardial Infarction

Highly selective and sensitive detection of cardiac troponin I (cTnI) is a powerful complement to clinical diagnosis of acute myocardial infarction (AMI). In this study, a strategy for cTnI detection was developed by constructing a universal biosensing interface composed of zwitterionic peptides and aptamers. The peptides were self-assembled onto gold chips, and some of them were biotinylated. The cTnI-specific binding aptamers were immobilized through the streptavidin-biotin system. Surface plasmon resonance (SPR) measurements revealed the preparation process. The developed aptasensor presents a linear detection with cTnI ranging from 20 ng/ml to 600 ng/ml and a detection limit of 20 ng/ml. The high immobilization of the aptamer enhances the sensitivity of the aptasensor and the calculated KD was 6.75 nM. Due to the outstanding antifouling property of the zwitterionic peptide, the developed aptasensor possesses a high resistance towards protein fouling. Moreover, the aptasensor has excellent selectivity and specificity towards cTnI in complex media. Hence, the proposed peptide-based aptasensor shows great potential for practical application in medium sized Myocardial Infarction (MI)

The Biological Effects of Sex Hormones on Rabbit Articular Chondrocytes from Different Genders

The aim of this study was to investigate the biological effects of sex hormones (17β-estradiol and testosterone) on rabbit articular chondrocytes from different genders. We cultured primary rabbit articular chondrocytes from both genders with varying concentration of sex hormones. We evaluate cell proliferation and biochemical functions by MTT and GAG assay. The chondrocyte function and phenotypes were analyzed by mRNA level using RT-PCR. Immunocytochemical staining was also used to evaluate the generation of collagen-II. This study demonstrated that 17β-estradiol had greater positive regulation on the biological function and gene expressions of articular chondrocytes than testosterone, with the optimal concentrations of 10−6 and 10−7 M, particularly for female chondrocytes

The Treatment of Keloid Scars via Modulating Heterogeneous Gelatin-Structured Composite Microneedles to Control Transdermal Dual-Drug Release

Keloid scarring is an abnormal scar disease characterised by excessive proliferation of fibroblasts and over-deposition of collagen during wound healing. Although various treatments for keloid scars have been developed, preventive medicine is believed to be a promising strategy. The skin barrier limits the gentle topical administration of medicaments such as creams and hydrogel dressings, resulting in reduced therapeutic efficacy. In recent years, microneedles (MNs) have been regarded as an appreciable device for topical administration without inducing side effects, and they are painless and do not cause bleeding. In this study, an MN patch with controlled transdermal dual-drug release was developed to achieve combinatory treatment of keloid scars using a heterogeneous gelatin-structured composite MN. Gelatin hydrogel was used as a substrate to load gallic acid (GA) and quercetin-loaded amphiphilic gelatin nanoparticles to fabricate dual-drug heterogeneous composite MNs. The results of the insertion test and mechanical properties of the MNs showed that the heterogeneous composite MN patches could be self-pressed into the stratum corneum and control dual-drug release at different time periods. GA was released at an earlier stage to retard the proliferation of fibroblasts, and quercetin was released at a later stage as a strong antioxidant to erase the generation of reactive oxygen species. Furthermore, real-time quantitative polymerase chain reaction data indicated that the gene expression of fibroblasts (such as Col I and III) was downregulated in the dual-drug system. The above results demonstrate that using heterogeneous composite MNs with the combination of dual-drug pharmacology is beneficial for preventing keloid scar formation

A Facile Fabrication of Biodegradable and Biocompatible Cross-Linked Gelatin as Screen Printing Substrates

This study focuses on preparation and valuation of the biodegradable, native, and modified gelatin film as screen-printing substrates. Modified gelatin film was prepared by crosslinking with various crosslinking agents and the electrode array was designed by screen-printing. It was observed that the swelling ratio of C-2, crosslinked with glutaraldehyde and EDC/NHS (1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide) was found to be lower (3.98%) than that of C-1 (crosslinked with only glutaraldehyde) (8.77%) and C-0 (without crosslinking) (28.15%). The obtained results indicate that the swelling ratios of both C-1 and C-2 were found to be lower than that of C-0 (control one without crosslinking). The Young’s modulus for C-1 and C-2 was found to be 8.55 ± 0.57 and 23.72 ± 2.04 kPa, respectively. Hence, it was conveyed that the mechanical strength of C-2 was found to be two times higher than that of C-l, suggesting that the mechanical strength was enhanced upon dual crosslinking in this study also. The adhesion study indicates that silver ink adhesion on the gelation surface is better than that of carbon ink. In addition, the electrical response of C-2 with a screen-printed electrode (SPE) was found to be the same as the commercial polycarbonate (PC) substrate. The result of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay suggested that the silver SPE on C-2 was non-cytotoxic toward L929 fibroblast cells proliferation. The results indicated that C-2 gelatin is a promising material to act as a screen-printing substrate with excellent biodegradable and biocompatible properties

Evaluation on the use of reactive dye-modified polylysine as the biomarker in immunochromatographic test application

An improved dye immunochromatographic test (DICT) using polylysine (PL) as conjugate spacer loading dye molecules to enhance chromophor color intensity with the potential of a simultaneous multicolored assay has been developed. To construct this new effective chromophor, a dyeing process coupling a reactive dye, Procion Blue MX-7RX (PB7RX), with PL of different molecular weights was performed. The optimal conjugate condition between PB7RX and PL was studied. It showed that under the optimized dyeing conditions, a PL molecular weight of 189.4 kDa and a molar ratio (mol dye/mol amine group in PL) of 1.5 were obtained. The resulting dyed PL chromophor, used as both a spacer and a color intensifier, was further labeled to a model antibody, anti-human serum albumin (anti-HSA), to build a PB7RX-PL-anti-HSA (PPA) conjugate. The PPA obtained in this way generated the highest color intensity of 19,455 assayed by immunochromatographic test strip under densitometer scanning. A competitive DICT for determination of HSA was carried out. A linear range between 0 and 18.77 μg/ml with a detection limit of 0.49 μg/ml was observed. A test for using dyed PL chromophors as biomarkers was also performed to demonstrate the feasibility of a multianalyte immunoassay

High Incidence of Cefoxitin and Clindamycin Resistance among Anaerobes in Taiwan

Susceptibilities to 16 antimicrobial agents were determined by measurement of MICs for 344 isolates of anaerobic bacteria recovered from patients with significant infections. Resistance rates varied among antimicrobial agents and the species tested. The β-lactams were more active in gram-positive than in gram-negative anaerobes. Resistance to meropenem was low (<1%). For β-lactam-β-lactamase inhibitors, piperacillin-tazobactam was most active for all species (resistance, <6%). The rates of resistance to cefoxitin (31 to 65%) and clindamycin (50 to 70%) for non-Bacteroides fragilis species of the B. fragilis group were higher than those for B. fragilis (4% resistant to cefoxitin and 33% resistant to clindamycin). Among members of B. fragilis group, Bacteroides thetaiotaomicron was the most resistant to clindamycin (70%) and cefoxitin (65%). Rates of susceptibility to imipenem and metronidazole for B. fragilis continue to be high compared to those from a previous study 10 years ago. However, resistance to metronidazole was found recently in five strains of B. fragilis. We analyzed the genetic relationships among the metronidazole-resistant B. fragilis strains by pulsed-field gel electrophoresis. The metronidazole-resistant B. fragilis strains showed genotypic heterogeneity, excluding the dissemination of a single clone