Glucose-responsive nanoparticles designed via a molecular-docking-driven method for insulin delivery

Anti-inflammatory Fucoidan-ConA oral insulin nanosystems for smart blood glucose regulation

The smart oral administration Insulin device has the potential to improve glycemic management. It can reduce the risk of hypoglycemia associated with exogenous Insulin (INS) therapy while also avoiding many of the disadvantages associated with subcutaneous injections. Furthermore, diabetes mellitus (DM) is an endocrine illness characterized by inflammation, and it is critical to minimize the amount of inflammatory markers in diabetic patients while maintaining average blood glucose. In this study, a responsive nanosystem vitamin B12-Fucoidan-Concanavalin A (VB12-FU-ConA NPs) with anti-inflammatory action was developed for smart oral delivery of Insulin. Con A has high sensitivity and strong specificity as a glucose-responsive material. Fucoidan has anti-inflammatory, immunomodulatory, and hypoglycemic functions, and it can bind to Con A to form a reversible complex. Under high glucose conditions, free glucose competitively binds to Con A, which swells the nanocarrier and promotes Insulin release. Furthermore, in the low pH environment of the gastrointestinal tract, positively charged VB12 and anionic fucoidan bind tightly to protect the Insulin wrapped in the carrier, and VB12 can also bind to intestinal epithelial factors to improve transit rate, thereby promoting INS absorption. In vitro tests showed that the release of nanoparticles in hyperglycemic solutions was significantly higher than the drug release in normoglycemic conditions. Oral delivery of the nanosystems dramatically lowered blood glucose levels in type I diabetic mice (T1DM) during in vivo pharmacodynamics, minimizing the risk of hypoglycemia. Blood glucose levels reached a minimum of 8.1 ± 0.4 mmol/L after 8 h. Administering the nanosystem orally notably decreased the serum levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in diabetic mice. The nano delivery system can be degraded and metabolized in the intestinal tract after being taken orally, demonstrating good biodegradability and biosafety. In conclusion, the present study showed that VB12-FU-ConA nanocarriers are expected to be a novel system for rationalizing blood glucose.

Dually crosslinked degradable polyionic micelles for sustained glucose-responsive insulin release

Glucose -sensitive delivery systems hold great promise as a therapeutic approach for high-incidence diabetes owing to their ability to release insulin whenever elevated glycemia is detected. However, they are unstable in a hyperglycemic environment, which leads to short-term sustained insulin release. Herein, we designed dually crosslinked insulin polyionic micelles (DCM@insulin) based on triblock polymers of o-glycol and phenylboronic acid-functionalized poly(ethylene glycol)-poly(dimethylamino carbonate)-poly(dimethylamino-trimethylene carbonate) (mPEG-P(AC-co-MPD)-PDMAC and mPEG-P(AC-co-MAPBA)-PDMATC, respectively) for sustained glucose-responsive insulin release. DCM@insulin with a phenylboronic acid ester structure (first crosslinking structure) enhanced glycemic responsiveness by regulating insulin release in a hyperglycemic environment. Additionally, the UV-crosslinking structure (second crosslinking structure) formed by the residual double bonds in AC units endowed DCM@insulin with the ability to effectively protect the loaded insulin against protease degradation and avoid burst release under multiple insulin release. The in vivo findings demonstrated that DCM@insulin effectively maintained glycemic levels (BGLs) within the normal range for 6 h in comparison to single-crosslinked micelles (SCM@insulin). Therefore, the glucose-responsive and dually crosslinked polyionic micelle system exhibits potential as a viable option for the treatment of diabetes.

Nanocarriers address intracellular barriers for efficient drug delivery, overcoming drug resistance, subcellular targeting and controlled release

The cellular barriers are major bottlenecks for bioactive compounds entering into cells to accomplish their biological functions, which limits their biomedical applications. Nanocarriers have demonstrated high potential and benefits for encapsulating bioactive compounds and efficiently delivering them into target cells by overcoming a cascade of intracellular barriers to achieve desirable therapeutic and diagnostic effects. In this review, we introduce the cellular barriers ahead of drug delivery and nanocarriers, as well as summarize recent advances and strategies of nanocarriers for increasing internalization with cells, promoting intracellular trafficking, overcoming drug resistance, targeting subcellular locations and controlled drug release. Lastly, the future perspectives of nanocarriers for intracellular drug delivery are discussed, which mainly focus on potential challenges and future directions. Our review presents an overview of intracellular drug delivery by nanocarriers, which may encourage the future development of nanocarriers for efficient and precision drug delivery into a wide range of cells and subcellular targets.

Electrostatic-Interaction-Aided Microneedle Patch for Enhanced Glucose-Responsive Insulin Delivery and Three-Meal-Per-Day Blood-Glucose Regulation

The phenylborate-ester-cross-linked hydrogel microneedle patch (MNP) was promising in the diabetic field for the glucose-responsive insulin-delivering property and simple fabrication process. However, the unfit design of the charging microneedle network limited the improvement of blood-glucose regulating performances. In this work, insulin-loaded phenylborate-ester-cross-linked MNPs, with the polyzwitterion property, were constructed based on the modified ε-polylysine and poly(vinyl alcohol). The relationship between the charging nature of the MNP network and insulin release was verified by regulating the content of postprotonated positively charged amino groups. The elaborately designed MNP possessed improved glucose-responsive insulin-delivering performance. The in vivo study revealed the satisfactory results on blood-glucose regulation by the optimized MNP under the mimic three-meal-per-day mode. Moreover, the insulin bioactivity in the MNP could be maintained for 2 weeks under 25 °C. In summary, this work developed an effective strategy to improve the glucose-responsive phenylborate-ester-cross-linked MNP and enhance its potential for clinical transformation.

Oral delivery of biomacromolecules by overcoming biological barriers in the gastrointestinal tract: an update

INTRODUCTION

Biomacromolecules have proven to be an attractive choice for treating diseases due to their properties of strong specificity, high efficiency, and low toxicity. Besides greatly improving the patient's complaint, oral delivery of macromolecules also complies with hormone physiological secretion, which has become one of the most innovative fields of research in recent years.

AREAS COVERED

Oral delivery biological barriers for biomacromolecule, transport mechanisms, and various administration strategies were discussed in this review, including absorption enhancers, targeting nanoparticles, mucoadhesion nanoparticles, mucus penetration nanoparticles, and intelligent bionic drug delivery systems.

EXPERT OPINION

The oral delivery of biomacromolecules has important clinical implications; however, these are still facing the challenges of low bioavailability due to certain barriers. Various promising technologies have been developed to overcome the barriers and improve the therapeutic effect of oral biomacromolecules. By considering safety and efficacy comprehensively, the development of intelligent nanoparticles based on the GIT environment has demonstrated some promise in overcoming these barriers; however, a more comprehensive understanding of the oral fate of oral biomacromolecules is still required.

Molecular Docking-Guided Design on Glucose-Responsive Nanoparticles for Microneedle Fabrication and "Three-Meal-per-Day" Blood-Glucose Regulation

It was greatly significant, but difficult, to develop stimulus-responsive polymeric nanoparticles with efficient protein-loading and protein-delivering properties. Crucial obstacles were the ambiguous protein/nanoparticle-interacting mechanisms and the corresponding inefficient trial-and-error strategies, which brought large quantities of experiments in design and optimization. In this work, a molecular docking-guided universal "segment-functional group-polymer" process was proposed to simplify the previous laborious experimental step. The insulin-delivering glucose-responsive polymeric nanoparticles for diabetic treatments were taken as the examples. The molecular docking study obtained insights from the insulin/segment interactions. It was then experimentally confirmed in six functional groups for insulin-loading performances of their corresponding polymers. The optimization formulation was further proved effective in blood-glucose stabilization on the diabetic rats under the "three-meal-per-day" mode. It was believed that the molecular docking-guided designing process was promising in the protein-delivering field.