No abstract

An alkaline phosphatase activity detection system was constructed based on the different quenching effect of the enzyme substrate and product on the β-CD-functionalized CdTe QDs.

The aggregation-induced emission (AIE) of a 1,2-diphenyl-1,2-di(p-tolyl)ethene (TPE) was explored as a novel fluorescence method for probing the assembling/disassembling of amphiphilic molecules. The fluorescence intensity was able to monitor the formation of micelles and determine the critical micelle concentration (CMC) of surfactants. The temperature-dependent micellization of the pharmaceutically important PEO-PPO-PEO copolymer, Pluronic F127, was further studied by using the TPE fluorescence spectrum intensity. Our results showed good agreement with those reported in the literature by using other methods. The special advantage of the AIE probe method was further explored to determine the assembling/disassembling process of the colored amphiphilic molecule, 1-[4-(3-phenylazophenoxy)butyl]triethylamine bromide (AzoC4), whose CMC value has not previously been described. Since the TPE fluorescence signal mainly comes from the aqueous phase, not from the inside of hydrophobic core, it provides a possible platform to study the CMC of those colored surfactants. Based on the novel fluorescence properties of TPE in the aggregated and dispersed states, one can conclude that the TPE method is a promising method for the determination of the CMC and critical micellization temperature (CMT), particularly having a special advantage to determine the assembling/disassembling process of colored amphiphilic molecules.

A novel comb-like derivative CPEG-g-DNQ was prepared by incorporating light responsive 2-diazo-1,2-naphthoquinone (DNQ) groups into the structure of comb-like poly(ethylene glycol) (CPEG). DLS and TEM results showed that CPEG-g-DNQ self-assembled into spherical micelles with an average size of about 135 nm in water. Upon exposure to light, the micelles could be disrupted because of the conversion of hydrophobic DNQ to hydrophilic 3-indenecarboylic acid. Additionally, hydrophobic coumarin 102 was successfully loaded into the micelles and photo-induced ON-OFF release was demonstrated by fluorescence spectroscopy. MTT assay revealed that the micelles are biocompatible. These photo-responsive micelles might have great potential for controlled release of hydrophobic drugs.

Abomasa (vells) were removed from 30 fetal calves at each of the 6th, 7th, 8th, and 9th mo of development. Milk clotting enzymes were exhaustively extracted in 10% NaCl solutions from the dried abomasal tissue. Total enzyme activity at each stage of fetal development was compared with that from abomasa of 3 to 5-day-old milk-fed calves. Enzyme activity was present in the abomasa of bovine fetuses as early as the 6th mo of development and increased as the fetuses approached full term. Average activity recovered from fetal vells at the 6th, 7th, 8th, and 9th mo of development represented 2, 7, 12, and 31% of the activity per vell, and 8, 14, 22, and 38% of the activity per unit vell weight, of that recovered from high quality calf vells. Diffusion patterns on casein-agar gels produced by bovine fetal extracts differed from those produced by commercial calf rennet extract or porcine pepsin.