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The effects of solvents on the structural stability of cross-linked lysozyme crystals were investigated by an immersion test using alkaline (0.1 M ammonia [NH₃] and 0.1 M sodium hydroxide [NaOH]), acidic (0.1 M acetic acid [CH₃COOH] and 0.1 M hydrochloric acid [HCl]) and organic (50% [v/v] and undiluted ethanol, acetone, 2-propanol and dimethyl sulfoxide [DMSO]) solvents. The morphology and lattice constants were monitored by optical microscopy and X-ray crystallography. The cross-linked crystals exhibited good stability against NH₃, CH₃COOH, HCl, ethanol, acetone and 2-propanol. However, samples preserved in DMSO and NaOH were severely degraded.

In the present investigation, a glucose sensor based on conducting polyaniline nanowire electrode junction (CPNEJ) has been reported. The CPNEJ platform was modified by glucose oxidase by cross-linking in the presence of glutaraldehyde. The signal transduction mechanism of the sensor is based on the change in micro electrode junction conductance as a result of glucose oxidation induced change in the polymer redox state. Small size of CPNEJ sensor causes to regenerate enzyme naturally without need of redox mediators, as a result it consumes minimum amount of oxygen and also gives very fast response. This sensor exhibited good linear response range from 1 mM to 20 mM of glucose concentration with excellent sensitivity of 12 μA/mM.

Sample preparation is an important procedure for atomic force microscope (AFM) studies. However, flexible virus particles have a tendency to aggregate together and are easily compressed during sample preparation or by AFM tip that subsequently hamper studying of virus by AFM. Herein, low concentration chemical reagent of glutaraldehyde (2%, v/v) is pre-mixed in virus suspension that facilitates the dispersion and observation of recombinant serotype 2 adeno-associated virus particles deposited on mica surface with little deformation.

Crosslinked film of hyperbranched poly(amine-ester) (HPAE) was prepared by crosslinking its terminal hydroxyl groups with glutaraldehyde (GA). Atom force microscope (AFM) and scanning electron microscope (SEM) reveals that they have smooth surfaces, dense and homogenous matrices. It was found that the water static contact angle is smaller than 41.7°, the tensile strength is higher than 8.9 MPa, the elongation at break is higher than 5.1%, the swelling degree is higher than 42% in water, and the Bovine hemoglobin (Hb) adsorption is relatively low. These results indicate that the crosslinked HPAE films might have some potential applications in many areas.

The thermal and degradable properties of carbodiimide (EDC) or glutaraldehyde (GTA) cross-linked gelatin membranes have been investigated in order to evaluate the effects of different concentrations of two kinds of cross-linking reagent on the stability of membranes. In the thermogram recorded from a gelatin membrane cross-linked with EDC solution, the endothermic peak of 0.8% EDC cross-linking gelatin was centered at about 61°C that was higher than other samples treated with EDC solutions. Denaturation temperature (Td) of gelatin samples increased on increasing EDC concentration (0.2% to 0.8%), in agreement with the simultaneous increased of the extent of cross-linking. But increasing GTA concentration from 0.05% to 0.6%, the Td values of gelatin samples were decreased from 66.2°C to 56.3°C . In addition, two endothermic peaks were observed in 0.4% and 0.6% GTA cross-linking groups because of the GTA concentration was too high to complete cross-linking reaction. Therefore, partial of gelatin membrane was cross-linked completely but others were not. In the thermogravimetric analysis, the proportion of cracking endothermic peak of 0.6% GTA cross-linking gelatin (g15G0.6) was higher than the peak of 0.6% EDC cross-linking gelatin (g15C0.6). Therefore, g15G0.6 cracked to smaller molecules has to absorb more calorific capacity than g15C0.6. The increase in the strength of covalent binding on increasing the proportion of endothermic peak was evident. The results of degradable rate were in agreement with the lower concentration of cross-linked reagent the faster degraded rate of gelatin membrane. The MTT assay showed that 15% gelatin cross-linked by 0.8% EDC has the least cytotoxicity, and cell activity of this group was similar to control group (blank dish). As the concentration of GTA in gelatin membranes was down to 0.05% or 0.1% the cell viability was returned to approach the value of control group.

The surface modification for immobilization of antibodies on the aluminum oxide surface was developed for biosensing application. The aluminum oxide has been received much attention since it has various advantages including low cost, hardness, resistance to organic solvents, and high capacitance. In addition, the aluminum oxide can prevent the leakage current in the electrical detection. For development of the protein anchorable surface, the aluminum oxide chip was treated with oxygen plasma and directly immersed in ethanol and toluene solution of 3-aminopropyltriethoxysilane (APTES). Next, this amine modified chip was immersed in the glutaraldehyde solution that contained sodium cyanoborohydride. Finally, the fluorescent materials, the Alexa 488, and the FITC conjugated anti-IgG were reacted to the aldehyde-modified surface. To verify the modified surface, the intensity of the fluorescence was measured and compared. The higher intensity of the fluorescence was observed when the APTES was dissolved in toluene rather than in ethanol. From the highest intensity of the fluorescence observed, the FITC conjugated anti-IgG was well immobilized on the modified surface of the aluminum oxide with APTES and glutaraldehyde. Thus, the proposed surface modification method can immobilize the proteins including antibodies, and can be applied for the various biological researches including biosensors and biochips.

Heat-sensitive, fiber optic, flexible endoscopes have made great contributions for the non-invasive diagnosis and treatment of disease. These heat-sensitive endoscopes need to be carefully cleaned, rinsed, high level disinfected, and rinsed to remove the disinfectant between each patient. Alkaline glutaraldehyde, ortho-phthalaldehyde, and peracetic acid are widely used high level disinfectants, but they each have limitations. We combined various concentrations of alcohols, salts, surfactants, buffers, and pH values with glutaraldehyde to find a chemically stable high level disinfectant that quickly kills all species of mycobacteria in suspension or dried onto a substrate, and can kill bacterial spores in a practical exposure time, and be easily rinsed from endoscope surfaces.