scholarly journals Immobilization of β-Galactosidase by Encapsulation of Enzyme-Conjugated Polymer Nanoparticles Inside Hydrogel Microparticles

Author(s):  
Narmin Suvarli ◽  
Lukas Wenger ◽  
Christophe Serra ◽  
Iris Perner-Nochta ◽  
Jürgen Hubbuch ◽  
...  

Increasing the shelf life of enzymes and making them reusable is a prominent topic in biotechnology. The encapsulation inside hydrogel microparticles (HMPs) can enhance the enzyme’s stability by preserving its native conformation and facilitating continuous biocatalytic processes and enzyme recovery. In this study, we present a method to immobilize β-galactosidase by, first, conjugating the enzyme onto the surface of polymer nanoparticles, and then encapsulating these enzyme-conjugated nanoparticles (ENPs) inside HMPs using microfluidic device paired with UV-LEDs. Polymer nanoparticles act as anchors for enzyme molecules, potentially preventing their leaching through the hydrogel network especially during swelling. The affinity binding (through streptavidin-biotin interaction) was used as an immobilization technique of β-galactosidase on the surface of polymer nanoparticles. The hydrogel microparticles of roughly 400 μm in size (swollen state) containing unbound enzyme and ENPs were produced. The effects of encapsulation and storage in different conditions were evaluated. It was discovered that the encapsulation in acrylamide (AcAm) microparticles caused an almost complete loss of enzymatic activity. Encapsulation in poly(ethylene glycol) (PEG)-diacrylate microparticles, on the other hand, showed a residual activity of 15–25%, presumably due to a protective effect of PEG during polymerization. One of the major factors that affected the enzyme activity was presence of photoinitiator exposed to UV-irradiation. Storage studies were carried out at room temperature, in the fridge and in the freezer throughout 1, 7 and 28 days. The polymer nanoparticles showcased excellent immobilization properties and preserved the activity of the conjugated enzyme at room temperature (115% residual activity after 28 days), while a slight decrease was observed for the unbound enzyme (94% after 28 days). Similar trends were observed for encapsulated ENPs and unbound enzyme. Nevertheless, storage at −26°C resulted in an almost complete loss of enzymatic activity for all samples.

2014 ◽  
Vol 47 (19) ◽  
pp. 6531-6539 ◽  
Author(s):  
Duangratchaneekorn Muenmart ◽  
Andrew B. Foster ◽  
Alan Harvey ◽  
Ming-Tsz Chen ◽  
Oscar Navarro ◽  
...  

Author(s):  
M. Müller ◽  
R. Hermann

Three major factors must be concomitantly assessed in order to extract relevant structural information from the surface of biological material at high resolution (2-3nm).Procedures based on chemical fixation and dehydration in graded solvent series seem inappropriate when aiming for TEM-like resolution. Cells inevitably shrink up to 30-70% of their initial volume during gehydration; important surface components e.g. glycoproteins may be lost. These problems may be circumvented by preparation techniques based on cryofixation. Freezedrying and freeze-substitution followed by critical point drying yields improved structural preservation in TEM. An appropriate preservation of dimensional integrity may be achieved by freeze-drying at - 85° C. The sample shrinks and may partially collapse as it is warmed to room temperature for subsequent SEM study. Observations at low temperatures are therefore a necessary prerequisite for high fidelity SEM. Compromises however have been unavoidable up until now. Aldehyde prefixation is frequently needed prior to freeze drying, rendering the sample resistant to treatment with distilled water.


Biomaterials ◽  
2019 ◽  
Vol 216 ◽  
pp. 119252 ◽  
Author(s):  
Shengliang Li ◽  
Qingyuan Deng ◽  
Xiao Li ◽  
Yongwei Huang ◽  
Xiaozhen Li ◽  
...  

ACS Nano ◽  
2021 ◽  
Author(s):  
Miao Zhao ◽  
Edward Leggett ◽  
Struan Bourke ◽  
Souzana Poursanidou ◽  
Sadie Carter-Searjeant ◽  
...  

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2047
Author(s):  
Naofumi Naga ◽  
Mitsusuke Sato ◽  
Kensuke Mori ◽  
Hassan Nageh ◽  
Tamaki Nakano

Addition reactions of multi-functional amine, polyethylene imine (PEI) or diethylenetriamine (DETA), and poly(ethylene glycol) diglycidyl ether (PEGDE) or poly(ethylene glycol) diacrylate (PEGDA), have been investigated to obtain network polymers in H2O, dimethyl sulfoxide (DMSO), and ethanol (EtOH). Ring opening addition reaction of the multi-functional amine and PEGDE in H2O at room temperature or in DMSO at 90 °C using triphenylphosphine as a catalyst yielded gels. Aza-Michael addition reaction of the multi-functional amine and PEGDA in DMSO or EtOH at room temperature also yielded corresponding gels. Compression test of the gels obtained with PEI showed higher Young’s modulus than those with DETA. The reactions of the multi-functional amine and low molecular weight PEGDA in EtOH under the specific conditions yielded porous polymers induced by phase separation during the network formation. The morphology of the porous polymers could be controlled by the reaction conditions, especially monomer concentration and feed ratio of the multi-functional amine to PEGDA of the reaction system. The porous structure was formed by connected spheres or a co-continuous monolithic structure. The porous polymers were unbreakable by compression, and their Young’s modulus increased with the increase in the monomer concentration of the reaction systems. The porous polymers absorbed various solvents derived from high affinity between the polyethylene glycol units in the network structure and the solvents.


Author(s):  
Panagiota Koralli ◽  
Spyridon Tsikalakis ◽  
Maria Goulielmaki ◽  
Stella Arelaki ◽  
Janina Müller ◽  
...  

Conjugated polymer nanoparticles (CPNs) have emerged as a new promising class of cancer theranostic agents due to their desirable optical features, such as high absorption coefficient and photoluminescence quantum yields,...


2015 ◽  
Vol 6 (21) ◽  
pp. 3962-3969 ◽  
Author(s):  
Chunhui Dai ◽  
Dongliang Yang ◽  
Wenjie Zhang ◽  
Biqing Bao ◽  
Yixiang Cheng ◽  
...  

We prepared a series of novel chiral far-red/near-infrared fluorescent CPNs with different nanoparticle sizes, which show size-dependent chirality and are successfully employed for cell imaging.


Materials ◽  
2017 ◽  
Vol 10 (12) ◽  
pp. 1420 ◽  
Author(s):  
Yasmine Braeken ◽  
Srujan Cheruku ◽  
Anitha Ethirajan ◽  
Wouter Maes

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