Chitosan-glutaraldehyde activated calcium pectinate beads as a covalent immobilization support

2017 ◽  
Vol 12 ◽  
pp. 266-274 ◽  
Author(s):  
Marwa I. Wahba
Author(s):  
VijayKrishna Raghunathan ◽  
Shin Ae Park ◽  
Nihar M. Shah ◽  
Christopher M. Reilly ◽  
Leandro Teixeira ◽  
...  

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 147
Author(s):  
Kristina A. Malsagova ◽  
Tatyana O. Pleshakova ◽  
Vladimir P. Popov ◽  
Igor N. Kupriyanov ◽  
Rafael A. Galiullin ◽  
...  

Gas-phase etching and optical lithography were employed for the fabrication of a silicon nanoribbon chip (Si-NR chip). The quality of the so-fabricated silicon nanoribbons (Si-NRs) was monitored by optical Raman scattering spectroscopy. It was demonstrated that the structures of the Si-NRs were virtually defect-free, meaning they could be used for highly sensitive detection of biological macromolecules. The Si-NR chips were then used for the highly sensitive nanoelectronics detection of DNA oligonucleotides (oDNAs), which represent synthetic analogs of 106a-5p microRNA (miR-106a-5p), associated with the development of autism spectrum disorders in children. The specificity of the analysis was attained by the sensitization of the Si-NR chip sur-face by covalent immobilization of oDNA probes, whose nucleotide sequence was complementary to the known sequence of miR-106a-5p. The use of the Si-NR chip was demonstrated to al-low for the rapid label-free real-time detection of oDNA at ultra-low (~10−17 M) concentrations.


2021 ◽  
Author(s):  
Bo Liu ◽  
Luanying Yang ◽  
Gang Wang ◽  
Sha He ◽  
Xiaobo Wang ◽  
...  

A simple and low-cost electrochemical CEA immunosensor was investigated via the self-polymerization of dopamine and a dithiol compound spacer for the covalent immobilization of antibodies. The designed CEA immunosensor exhibited a linear response and a low detection limit.


Biomolecules ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 657
Author(s):  
Cintia Wanda Rivero ◽  
Natalia Soledad García ◽  
Jesús Fernández-Lucas ◽  
Lorena Betancor ◽  
Gustavo Pablo Romanelli ◽  
...  

Nowadays, enzyme-mediated processes offer an eco-friendly and efficient alternative to the traditional multistep and environmentally harmful chemical processes. Herein we report the enzymatic synthesis of cladribine by a novel 2′-deoxyribosyltransferase (NDT)-based combined biocatalyst. To this end, Lactobacillus delbrueckii NDT (LdNDT) was successfully immobilized through a two-step immobilization methodology, including a covalent immobilization onto glutaraldehyde-activated biomimetic silica nanoparticles followed by biocatalyst entrapment in calcium alginate. The resulting immobilized derivative, SiGPEI 25000-LdNDT-Alg, displayed 98% retained activity and was shown to be active and stable in a broad range of pH (5–9) and temperature (30–60 °C), but also displayed an extremely high reusability (up to 2100 reuses without negligible loss of activity) in the enzymatic production of cladribine. Finally, as a proof of concept, SiGPEI 25000-LdNDT-Alg was successfully employed in the green production of cladribine at mg scale.


2014 ◽  
Vol 1060 ◽  
pp. 45-49
Author(s):  
Kamonrak Cheewatanakornkool ◽  
Pornsak Sriamornsak

The main objective of this study was to fabricate biopolymer-based microbeads, providing enteric properties and controlled release of diclofenac sodium, using layer-by-layer technique. The calcium pectinate microbeads have been designed and coated with chitosan and pectin multilayers. Drug release was performed in simulate gastric fluid (pH 1.2) for 2 hours, followed by pH 6.8 buffer for 8 hours. The effects of chitosan concentration, number of layer and drying technique on drug release were investigated. The results showed that the calcium pectinate microbeads could be simply prepared by ionotropic gelation and then coated with chitosan and pectin solutions using layer-by-layer procedure. The diameter of the microbeads ranged from 800 to 1000 μm for air-dried samples and from 1 to 2 mm for freeze-dried samples. The freeze-dried microbeads had a rough surface and many pores inside, as observed by SEM. The microbeads coated with 4% chitosan/4% pectin revealed a slower drug release than those coated with 1% chitosan/4% pectin and demonstrated a controlled release pattern. Moreover, different drying techniques and numbers of layer also influenced drug release behavior of the prepared microbeads.


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