Modification Of Gums By Periodate Oxidation: A Natural Cross-Linker

Scientists throughout the world are in search of novel modified biopolymer to fabricate smart drug delivery systems based on hydrogel formulations using several cross-linkers like glutaraldehyde, glyoxal, epichlorhydrin, adipic acid dihydrazide, carbodiimide, genipin, etc. Agents that are fused into the polymeric structure like isocyanates, glutaraldehyde, polyepoxides, etc., and are extremely toxic in nature. In addition, these are susceptible to percolate out into the body on biodegradation of polymeric structure. As an alternative to these toxic cross-linking agents, the periodate-Schiff base staining technique is widely being used for cross-linking in biology and biochemistry. The mechanism of this cross-linking technique is based on the reaction in-between the Schiff reagent and the aldehydes produced via the periodate oxidation. During the past few decades, several researchers have already been studied on the natural gums and also, developed their dialdehyde derivatives via the periodate oxidation technique. These periodate oxidized gums are being used to cross-link gelatin, other proteins and chitosan to develop various smart systems for drug delivery, tissue engineering, wound dressing, edible films, etc. The current review presents a comprehensive discussion of the available reported literature on the periodate oxidation of various gums and their use as natural cross-linker.

Synthesis and identification of artificial antigen of spinosin / 中国中药杂志

Immunogenic antigen (spinosin-BSA) and coating antigen (spinosin-OVA) of spinosin were synthesized by sodium periodate oxidation method. UV scanning analysis method showed that these two spinosins were successfully conjugated with carrier protein and the coupling ratio was 17 and 13.7, respectively. Meanwhile, when immunized by spinosin-BSA，the mice can produce anti-spinosin antibodies with the high titer (1:32 000),specificity (IC₅₀ 211.6 μg·L⁻¹) and low cross-reaction rate measured by ELISA tests. The artificial antigen of spinosin was successfully synthesized, which can be applied for preparation of monoclonal antibodies and establishment of appropriate immune method.

Preparation and identification of Jujuboside A artificial antigen / 中国中药杂志

Immunogenic antigen (jujuboside A-BSA) and coating antigen (jujuboside A-OVA) of jujuboside A were synthesized by sodium periodate oxidation method for the first time. Jujuboside A artificial antigen was confirmed by matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI-TOF-MS). The titer and specificity of the antibody in serum of immunized mice were detected by enzyme-linked immunosorbent assay (ELISA). The corrected relation curve of inhibition rate showed that the antibody against Jujuboside A obtained from immunized mice could bind to jujuboside A and the titer was up to 1∶4 000. The jujuboside A artificial antigen was synthesized, which can be used further to preparation of monoclonal antibody and the pharmacokinetics study of jujuboside A in laboratory animals.

Research on PEGylated uricase by periodate oxidation and reductive- amination / 中国药科大学学报

@#PEGylated uricase was prepared with the N-terminal amino site-specific modification by periodate oxidation followed by reductive-amination. A monomethoxy poly(ethylene glycol)intermediate was synthesized by amidation from monomethoxy poly(ethylene glycol)amine hydrochloride 20000(mPEG20000-NH2 ·HCl)with the relative molecular mass of 20 kD and N-(tert-butoxycarbonyl)-L-serine(Boc-Ser-OH), and then the Boc group of the intermediate was removed by trifluoroacetic acid(TFA)to produce the desired product Ser-mPEG20000. This compound could be oxidated by periodate to obtain a new poly(ethylene glycol)aldehyde derivative with high activity, which could be used to modify proteins with the N-terminal amino site-specific PEGylation after ultrafiltration, and the modification conditions to uricase by Ser-mPEG20000 were optimized. The structures of poly(ethylene glycol)intermediate and the target product were characterized by IR and 1H NMR, and the overall yield of the target product was 72. 8%. The preliminary modification to uricase indicated that the desired product Ser-mPEG20000 could modify proteins easily and efficiently. The optimal modification conditions of uricase PEGylated by Ser-mPEG20000 were obtained as follows: the molar ratio of Ser-mPEG20000 to uricase was 2 ∶1; the pH value of solution was 5. 0; the reaction temperature was 25 °C and the reaction time was 6 h.

Synthesis and identification of artificial antigen of loganin and preliminary study on its immunogenicity / 中草药

Objective: To synthesize and identify the artificial antigen of loganin for the first time, and provide a foundation for the preparation of specific monoclonal antibody and establishment of immunoassay method. Methods: Sodium periodate oxidation method was used to synthesize immunogenic antigen (loganin-BSA) and coating antigen (loganin-OVA) of loganin. Whether loganin was conjugated with BSA and OVA or not was confirmed by matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI-TOF-MS). The titer and specificity of the antibody in serum of immunised mice were detected by enzyme-linked immunosorbent assay (ELISA). Results: The results of MALDI-TOF-MS indicated that loganin was conjugated to BSA. The antibody against loganin obtained from immunised-mice could bind to loganin and the titer was up to 1:40 000. Conclusion: The artificial antigen of loganin was synthesized, which can be used further in the preparation of monoclonal antibody, application in quality control of Chinese materia medica and the pharmacokinetic study of loganin in laboratory animals.

Synthesis and identification of artificial antigen of icariin / 中国药学杂志

OBJECTIVE: To synthesize conjugates as artificial complete antigen and coated antigen of icariin to establish an enzyme linked immunosorbent assay (ELISA).

Synthesis and immunogenicity indentification of artificial antigen of ginsenoside Rg1 / 中草药

Objective: To synthesize the artificial antigen of ginsenoside Rg1-bovine serum albumin (Rg1-BSA) and the artificial coated antigen of ginsenoside Rg1-polylysine (Rg1-PLL), and to provide the basis for the preparation of monoclonal antibody (MAb) and the establishment of immunoassay method. Methods: Rg1-BSA and Rg1-PLL were synthesized by sodium periodate oxidation method. The characterization of the synthesis was examined by UV spectrometry and TLC method. The titer and specificity of the antibody in serum of immunised mice were detected by indirect enzyme-linked immunosorbent assay (I-ELISA) and indirect competitive enzyme-linked immunosorbent assay (I-CELISA), respectively. Results: According to the UV and TLC, the Rg1 was successfully conjugated with BSA and PLL. I-ELISA and IC-ELISA methods were developed using Rg1-PLL. The anti-Rg1 antibody obtained from immunized mice could bind to Rg1 specially and the titer was up to 1:80000. Conclusion: The artificial immunogen Rg1-BSA and coated antigen Rg1-PLL are successfully synthesized, which could be used to prepare the MAb of Rg1 and establish the immunoassay method.