Synthesis of poly(N-isopropylacrylamide-co-2-hydroxyethyl methacrylate) with low polydispersity using ultrasonic irradiation.

Poly(N-isopropylacrylamide-co-2-hydroxyethyl methacrylate) having low polydispersity was synthesized in mixed solvent of ethanol and water using ultrasonic irradiation without any chemical polymerization initiator. The effects of the volume fraction of ethanol in the solvent, the molar ratio of two monomers, the monomer concentration and the ultrasonic power intensity on the time courses of the conversion to the polymer, the number average molecular weight, and the polydispersity of synthesized polymer were investigated in order to determine the optimal conditions to synthesize the copolymers with a narrow molecular weight distribution (i.e. low polydispersity). The optimum volume fraction of ethanol in the solvent was 60 vol% to synthesize the copolymers with a low polydispersity. A higher ultrasonic power intensity resulted in a faster polymerization rate and a lower number average molecular weight. The polydispersity was less than 1.5 for all ultrasonic power intensities up to 450 W/dm3 applied in this work. A higher monomer concentration gave a faster polymerization rate and a higher number average molecular weight. The polydispersity was less than 1.5 when the monomer concentration was lower than 0.4 mol/dm3. A higher molar ratio of N-isopropylacrylamide resulted in a higher polymerization rate and a lower number average molecular weight. The copolymers with polydispersity less than 1.5 can be obtained regardless of the molar ratio of N-isopropylacrylamide. The copolymers synthesized by the ultrasonic polymerization method had a high temperature responsibility.

Determination of serum lipoprotein lipase using a latex particle-enhanced turbidimetric immunoassay with an automated analyzer.

BACKGROUND: Lipoprotein lipase (LPL) plays a central role in triglyceride-rich lipoprotein metabolism by catalyzing the hydrolysis of triglycerides. Quantification of serum LPL is useful for diagnosing lipid disorders, but there is no rapid method of measuring LPL for clinical use. METHODS: We developed a rapid and sensitive latex particle-enhanced turbidimetric immunoassay (LTIA) serum LPL using latex bead-immobilized anti-LPL monoclonal antibodies. The assay was performed on a Hitachi 7700 P analyzer and evaluated for its validity as a method of quantitating the serum LPL concentration in parallel with ELISA. RESULTS: Dilution tests using LTIA produced a calibration curve from 0.5 to 800ng/ml. Within-run CV was obtained in the range of 2.2-5.5%. No interference was observed in the testing of specimens containing potentially interfering substances such as bilirubin-F and C, hemoglobin, triglycerides and rheumatoid factor. A strong correlation between LTIA and ELISA was confirmed (n=40, r=0.967, y=0.99x-1.86). The normal range of LPL in pre-heparin serum was 50-77ng/ml and in post-heparin plasma 354-410ng/ml, respectively. CONCLUSION: The LTIA assay is applicable in quantitating the concentration of LPL in both pre-heparin serum and post-heparin plasma. This assay is more convenient and faster than ELISA and highly suitable for clinical routine analysis.