[Obtaining and characteristics of domestic preparation interferon alpha-2b with prolonged effect].

Pegylated interferon alpha-2b (PEG-IFN alpha-2b) is a domestic preparation of a modified recombinant interferon alpha-2b with prolonged effect. The preparation was obtained by N-terminal pegylation of IFN alpha-2b with polyethylene glycol (PEG). This paper presents the method of PEG-IFN alpha-2b synthesis and characteristics of the obtained product. PAAG electrophoresis, Western blot analysis and MALDI-TOF mass-spectrometry confirm that the preparation is an N-terminal pegylated IFN alpha-2b that contains no more than 10% of dipegylated IFN alpha-2b. The comparison of PEG-IFN alpha-2b with its foreign analogue has revealed the similarity of their biological activity and pharmacokinetic parameters.

Liquid photopolymerizable compositions as immobilized matrix of biosensors.

Series of liquid photopolymerizable compositions (LPhPC) based on oligouretanemetacrylate (OUM-1000T and OUM-2000T) and oligocarbonatemetacrylate (OCM-2), monomethacrylic ether of ethylene glycol and vinylpyrrolidone (VP) were tested. It was shown that the LPhPC, which contained VP (as basic hydrophylic matrix), OCM-2 (cross-linking agent) and OUM-2000T (to increase adsorption of polymer) was the most optimal. The blend contained 3 g/100 ml of enzyme. ISFET based biosensors for analysis of glucose and urea had the following characteristics: linear response in the range of concentrations 0.1-10 mmol/l, 0.05-20 mmol/l, angle of slope of concentration curve--30 mV/pC, 38 mV/pC, and response time of approximately 10-15, 5-10 min, correspondingly. The value of Km for immobilized urease and beta-glucose oxidase (GOD) achieved 0.85 and 3.1 mmol/l, respectively. It was established that under immobilization conditions at 20 degrees C the residual activity of GOD was about 35% from the initial level, the residual activity of horseradish peroxidase (HRP) and urease was 42% and 20%, respectively. In case of an immobilization of GOD at -50 degrees C its residual activity reached almost 50% from the initial level. It was investigated how different sources of UV radiation and different substances (including specific and non-specific substrates) influenced stability of the enzymes in the LPhPC and in the prepared membrane at storage. Dynamics of changes of enzyme activity at the process of photo immobilization was characterized, and requirements for enzyme maximal storage were selected. The proposed LPhPC may be prepared in advance since enzymes do not lose their activity during 2 months. Therefore, two processes, i.e. manufacturing of a transducer and preparation of a biological membrane on its surface, can be combined in one. In order to achieve this, approaches of modern electronics, such as for example photolithography, can be used. The developed LPhPC is homogenous, non-active to biological substances, permeable for the analyzed sample, can be prepared using a simple immobilization procedure, and has a defined hydrophobic-hydrophilic balance and sufficient level of adhesion to transducer surfaces. These all cover the requirements to modern biosensors.

[Liquid photo-polymerized compositions as an immobilized matrix of biosensors]. / Zhidkie fotopolimerizuiushchiesia kompozitsii v kachestve immobilizatsionnogo matriksa.

Series of liquid photopolimerized compositions based on oligourethanemetacrylate (OUM-1000T and OUM-2000T) and oligocarbonatemethacrylate (OCM-2), butilmethacrylate, methacrylic that acid, monomethacrylic ether of ethylene glycol and vinylpirrolidone (VP) were tested. It was shown the optimal variant of enzyme sensor development was a composition containing VP (a basic hydrophylic matrix), OCM-2 (crosslinked components) and OUM-2000T (crosslinked and increasing adsorption of polymer component). The blend contains 3% of enzyme. The obtained biosensors as based on immobilized beta-glucose oxidase and ureases have the following charachteristics: the linear response in the range of the concentration 0.1-10 mM, 0.05-20 mM, angle of slope of curve 30 mV/pC, 38 mV/pC, and response time 10-15, 5-10 mines, respectively. The maximal response of urease sensor was in the diapazon of pH 6.0-6.5. The increase of NaCl concentration in the solution to 300 mM caused reduction of sensor response. Under this concentration the was latter equal to half of initial response. Further increase of NaCl concentration (to 500 mM) doesn't lead to further response reduction. K(m) was calculated and it was shown, that amount of immobilized urease and beta-glucose oxidase in photopolymer material was equal 0.85 and 3.1 mM respectively.

[Optimization of the conditions of immobilization of enzymes in a photopolymeric membrane]. / Optimizatsiia uslovii immobilizatsii fermentov v fotopolimernoi membrane.

The residual activity of enzymes immobilized in the membrane on the basis on 1-vinyl-2-pyrrolidinone as photopolymerizable composition is studied. It is established, that under conditions of the immobilization at 20 degrees C the residual activity glucoseoxidase is about 35% from a initial level, horseredish peroxidase and urease from Jeack beans--42% and 20%, respectively. In case of an immobilization of beta-glucoseoxidase -50 degrees C it reaches almost 50% from a initial level. It was investigated the influence of different sources of UV-radiation and different substances on stability of the enzymes in the composition and in the immobilization matrix at storage. Dynamic of changes of enzyme activity at the photoimmobilization was characterized, and also the requirements for providing of its maximal storage was selected.

[Electrochemical sensor based on photopolymeric membranes for determining urea]. / Elektrokhimicheskii sensor na osnove fotopolimernykh membran dlia opredeleniia mocheviny.

A new electrochemical enzymatic sensor based on the ion selective field effect transistors (ISFETs) and photocurable membrane was developed for the determination of urea. For the immobilization of urease on the gate surface of the ISFET a simple method, involving the use of liquid photocurable compositions on the basis of vinylpirollidone, oligouretanemetacrylate and oligocarbonatemetacrylate, was applied. The linearange of the response of the developed electrochemical sensor lies in the range 0.05-20 mM. The latter corresponds to the claims of the medical practice. The overall time of the analysis is 5-10 min. The effects of the buffer concentration and its pH as well as temperature and presence of ammonia ions in the measuring medium on the amplitude of the sensor response were estimated. The duration of sensor work is as shortest 40 days. The proposed sensor on the basis of the ISFET is promising for the express analysis of the level urea in blood, while the developed method of membrane preparation with entrapped enzyme can be combined with the integral technology of producing of the biosensors semiconductor transducers.

[Photopolymers as an immobilized matrix in biosensing]. / Fotopolimery kak immobilizatsionnyi matriks v biosensorike.

Biosensors are perspective devices for analysis of substances in chemistry, biological chemistry, medicine, biotechnology and also for environment status monitoring. Their advantages are compact size, short time of analysis, display high response and simplicity in usage. The working characteristics of biosensors often depend on efficacy of a biological stuff immobilization on the surface of transducer. In this context there is a need for development of immobilization methods capable to provide for execution of the following demands: 1) compatibility of this process with technology of building transducer; 2) simplicity in fulfillment, cheapness and expressness at manufacture of biomembranes; 3) ability to provide the maximal safety of a biological stuff activity and its high adhesion to a surface of transducer; 4) reproducibility at serial application and capacity of standardizing. Usage of photocrosslinked and photopolymerized compound at the immobilization of a biological stuff allows to provide execution of the listed above demands. The present review is devoted to features of application of the given class of compound at building of biosensors.