β-Cyclodextrin grafted polyethyleneimine hydrogel immobilizing hydrophobically modified glucose oxidase

Recent advances in glucose-oxidase-based nanocomposites for diabetes diagnosis and treatment

Glucose oxidase (GOx) has attracted a lot of attention in the field of diabetes diagnosis and treatment in recent years owing to its inherent biocompatibility and glucose-specific catalysis. GOx can effectively catalyze the oxidation of glucose in the blood to hydrogen peroxide (H2O2) and glucuronic acid and can be used as a sensitive element in biosensors to detect blood glucose concentrations. Nanomaterials based on the immobilization of GOx can significantly improve the performance of glucose sensors through, for example, reduced electron tunneling distance. Moreover, various insulin-loaded nanomaterials (e.g., metal-organic backbones, and mesoporous silica nanoparticles) have been developed for the control of blood glucose concentrations based on GOx catalytic chemistry. These nano-delivery carriers are capable of releasing insulin in response to GOx-mediated changes in the microenvironment, allowing for a rapid return of the blood microenvironment to a normal state. Therefore, glucose biosensors and insulin delivery vehicles immobilized with GOx are important tools for the diagnosis and treatment of diabetes. This paper reviews the characteristics of various GOx-based nanomaterials developed for glucose biosensing and insulin-responsive release as well as research progress, and also highlights the current challenges and opportunities facing this field.

Immobilization of lipase on β-cyclodextrin grafted and aminopropyl-functionalized chitosan/Fe3O4 magnetic nanocomposites: An innovative approach to fruity flavor esters esterification

The lipase from Bacillus licheniformis NCU CS-5 was immobilized onto β-cyclodextrin (CD) grafted and aminopropyl-functionalized chitosan-coated Fe₃O₄ magnetic nanocomposites (Fe₃O₄-CTS-APTES-GA-β-CD). Fourier transform infrared spectroscopy, thermogravimetry analysis, X-ray diffraction, scanning electron microscopy and transmission electron microscopy showed that not only the functionalized magnetic nanoparticles were synthesized but also the immobilized lipase was successfully produced. The immobilized lipase exhibited higher optimal pH value (10.5) and temperature (60℃) than the free lipase. The pH and thermal stabilities of the immobilized lipase were improved significantly compared to the free lipase. The immobilized lipase remained more than 80% of the relative activity at temperature of 60 ℃ and pH 12.0. The immobilized lipase also remained over 80% of its relative activity after 28 days of storage and 15 cycles of application. The application of the immobilized lipase in esterification of isoamyl acetate and pentyl valerate showed that maximum esterification efficiency was achieved in n-hexane having 68.0% and 89.2% respectively. Therefore, these results indicated that the Fe₃O₄-CTS-APTES-GA-β-CD nanoparticles are novel carriers for immobilizing enzyme, and the immobilized lipase can be used as an innovative green approach to the synthesis of fruity flavor esters in food industry.

Cyclodextrin embedded covalently crosslinked networks: synthesis and applications of hydrogels with nano-containers

Recent advancements in the synthesis of hydrogels containing cyclodextrin (CD) units within the gel network have been reviewed.

Enzyme production ofd-gluconic acid and glucose oxidase: successful tales of cascade reactions

This review mainly focuses on the use of glucose oxidase in the production ofd-gluconic acid, which is a reactant of undoubtable interest in different industrial areas. As example of diverse enzymatic cascade reactions.

Glucose-sensitive polymer nanoparticles for self-regulated drug delivery

Glucose-sensitive drug delivery systems, which can continuously and automatically regulate drug release based on the concentration of glucose, have attracted much interest in recent years. Self-regulated drug delivery platforms have potential application in diabetes treatment to reduce the intervention and improve the quality of life for patients. At present, there are three types of glucose-sensitive drug delivery systems based on glucose oxidase (GOD), concanavalin A (Con A), and phenylboronic acid (PBA) respectively. This review covers the recent advances in GOD-, Con A-, or PBA-mediated glucose-sensitive nanoscale drug delivery systems, and provides their major challenges and opportunities.

Multifunctionalized polyethyleneimine-based nanocarriers for gene and chemotherapeutic drug combination therapy through one-step assembly strategy

Gene therapy combined with chemotherapy to achieve synergistic therapeutic effects has been a hot topic in recent years. In this project, the human tumor necrosis factor-related apoptosis-inducing ligand-encoding plasmid gene (TRAIL) and doxorubicin (Dox)-coloaded multi-functional nanocarrier was constructed based on the theory of circulation, accumulation, internalization, and release. Briefly, polyethyleneimine (PEI) was selected as skeleton material to synthesize PEI–polyethylene glycol (PEG)–TAT (PPT). Dox was conjugated to PEI using C6-succinimidyl 6-hydrazinonicotinate acetone hydrazone (C6-SANH), and a pH-sensitive Dox-PEI (DP) conjugate was obtained. Then, intracellular cationic pH-sensitive cellular assistant PPT and DP were mixed to condense TRAIL, and TRAIL–Dox coloaded PPT/DP/TRAIL (PDT) nanocarriers were obtained by one-step assembly. TRAIL was completely condensed by DP or PPT when mass ratios (DP/PPT to TRAIL) were up to 100:64, which indicated that DP and PPT could be mixed at any ratio for TRAIL condensation. The intracellular uptake rate of PDT was enhanced (P<0.05) when the contents of PPT in PPT+DP increased from 0 to 30%. Free Dox and TRAIL-loaded nanocarriers (PPT/C6-SANH-PEI/TRAIL [PCT]) were selected as controls to verify the synergistic antitumor effects of PDT. Compared with free TRAIL, TRAIL-protein expression was upregulated by PDT and PCT on Western blotting assays. The in vitro cytotoxicity of PDT was significantly enhanced compared to free Dox and PCT (P<0.01). Furthermore, murine PDT nanocarriers showed higher in vivo antitumor ability than both the Dox group (P<0.05) and the murine PCT group (P<0.05). These results indicated that the TRAIL + Dox synergistic antitumor effect could be achieved by PDT, which paves the way to gene–drug combination therapy for cancer.

Biomolecule-Responsive Hydrogels in Medicine

Recent advances and applications of biomolecule-responsive hydrogels, namely, glucose-responsive hydrogels, protein-responsive hydrogels, and nucleic-acid-responsive hydrogels are highlighted. However, achieving the ultimate purpose of using biomolecule-responsive hydrogels in preclinical and clinical areas is still at the very early stage and calls for more novel designing concepts and advance ideas. On the way toward the real/clinical application of biomolecule-responsive hydrogels, plenty of factors should be extensively studied and examined under both in vitro and in vivo conditions. For example, biocompatibility, biointegration, and toxicity of biomolecule-responsive hydrogels should be carefully evaluated. From the living body's point of view, biocompatibility is seriously depended on the interactions at the tissue/polymer interface. These interactions are influenced by physical nature, chemical structure, surface properties, and degradation of the materials. In addition, the developments of advanced hydrogels with tunable biological and mechanical properties which cause no/low side effects are of great importance.

Glucose Oxidase-Based Glucose-Sensitive Drug Delivery for Diabetes Treatment

The glucose-sensitive drug delivery systems based on glucose oxidase (GOD), which exhibit highly promising applications in diabetes therapy, have attracted much more interest in recent years. The self-regulated drug delivery systems regulate drug release by glucose concentration automatically and continuously to control the blood glucose level (BGL) in normoglycemic state. This review covers the recent advances at the developments of GOD-based glucose-sensitive drug delivery systems and their in vivo applications for diabetes treatment. The applications of GOD-immobilized platforms, such as self-assembly layer-by-layer (LbL) films and polymer vesicles, cross-linking hydrogels and microgels, hybrid mesoporous silica nanoparticles, and microdevices fabricated with insulin reservoirs have been surveyed. The glucose-sensitive drug delivery systems based on GOD are expected to be a typical candidate for smart platforms for potential applications in diabetes therapy.

Investigation of the Sequential Actions of Doxorubicin and p53 on Tumor Cell Growth Via Branched Polyethylenimine-β-cyclodextrin Conjugates

The combination of gene therapy and chemotherapy has showed increased therapeutic efficacy in the treatment of cancers, but it is not well investigated about the actual coordination pattern between therapeutic gene and chemical drug. In this work, p53/BPEI-β-CD/AD-dox complex was fabricated and employed to investigate the interaction manner between p53 and doxorubicin (Dox). Briefly, branched polyethylenimine (BPEI) was conjugated with β-cyclodextrin hydrate (β-CD) to form BPEI-β-CD backbone, and p53 plasmid was condensed by positively charged BPEI via electrostatic interaction, while Dox was first conjugated with adamantine (AD) and then assembled with BPEI-β-CD backbone via the host-guest interaction. It was found that the BPEI-β-CD backbone possessed high endocytosis efficiency but low cytotoxicity. Moreover, p53/BPEI-β-CD/AD-dox complex released Dox and enabled the expression of p53 gene in a sequential manner, and the released Dox and expressed p53 gene showed successive inhibition of the growth of HeLa cells in vitro. With the ability to co-deliver chemical drug and therapeutic gene and exert their inhibitory actions on tumor cell growth in a sequential manner, this DNA/BPEI-β-CD/AD-drug complex via electrostatic interaction and host-guest assembly not only achieved long-term efficacy in inhibiting tumor cell growth but also can be employed as a platform to investigate the coordination pattern between chemical drugs and therapeutic genes for other purposes.

Evaluation of multilayer coated magnetic nanoparticles as biocompatible curcumin delivery platforms for breast cancer treatment

A novel biocompatible multi-layer iron oxide magnetic nanoparticles with sustained sensitive release profile, and improved cellular uptake.