Gelatin/alginate-based microspheres with sphere-in-capsule structure for spatiotemporal manipulative drug release in gastrointestinal tract

Dynamic gastrointestinal digestion of tilapia (Oreochromis mossambicus) skin gelatin: changes of hydrolysate properties and dipeptidyl peptidase IV inhibitory activity

BACKGROUND

It is important to study the physicochemical properties of tilapia (Oreochromis mossambicus) skin gelatin and the changes in dipeptidyl peptidase IV (DPP-IV) inhibition activity during gastrointestinal digestion in order to understand and exploit the potential of tilapia as a source of DPP-IV inhibitory peptides.

RESULTS

The DPP-IV inhibition of fish-skin gelatin increased from 9.92 ± 0.76% to 36.75 ± 0.98%, and further to 51.06 ± 1.23%, following simulated intestinal digestion for a period of 60 min. After gastric digestion, the degree of hydrolysis (DH) was 18.19 ± 0.48%, the average molecular weight (AMW) was 219 ± 7.19 kDa, the sum of charged groups was -5.08 ± 0.32, and the surface hydrophobicity of the hydrolysate was 24.81 ± 0.25. After intestinal digestion, these values changed to 27.72 ± 0.47%, 146.56 ± 8.16 kDa, -8.09 ± 0.32, and 13.04 ± 0.53, respectively. The DH and sum of charged groups exhibited positive correlations with DPP-IV inhibition (0.94 and 0.71, respectively), but AMW showed a negative correlation (-0.96). MATLAB fit functions were applied to predict theoretical inhibition values, with the fitted equation: DPP-IV inhibition = 2.5885 × DH - 0.0983 × AMW - 1.0047 × sum of charged groups + 3.5118. The test set for the multiple linear regression model demonstrated an R2 equal to or greater than 0.8.

CONCLUSION

The DH, AMW, and sum of charged groups in the hydrolysate correlated with DPP-IV inhibition, and the fitted equation predicted DPP-IV inhibition effectively in tilapia skin gelatin. © 2024 Society of Chemical Industry.

Microfluidic Gastrointestinal Cell Culture Technologies-Improvements in the Past Decade

Gastrointestinal cell culture technology has evolved in the past decade with the integration of microfluidic technologies, bringing advantages with greater selectivity and cost effectiveness. Herein, these technologies are sorted into three categories, namely the cell-culture insert devices, conventional microfluidic devices, and 3D-printed microfluidic devices. Each category is discussed in brief with improvements also discussed here. Introduction of different companies and applications derived from each are also provided to encourage uptake. Subsequently, future perspectives of integrating microfluidics with trending topics like stool-derived in vitro communities and gut-immune-tumor axis investigations are discussed. Insights on modular microfluidics and its implications on gastrointestinal cell cultures are also discussed here. Future perspectives on point-of-care (POC) applications in relations to gastrointestinal microfluidic devices are also discussed here. In conclusion, this review presents an introduction of each microfluidic platform with an insight into the greater contribution of microfluidics in gastrointestinal cell cultures.

The contemplation of amylose for the delivery of ulcerogenic nonsteroidal anti-inflammatory drugs

This manuscript proposes an innovative approach to mitigate the gastrointestinal adversities linked with nonsteroidal anti-inflammatory drugs (NSAIDs) by exploiting amylose as a novel drug delivery carrier. The intrinsic attributes of V-amylose, such as its structural uniqueness, biocompatibility and biodegradability, as well as its capacity to form inclusion complexes with diverse drug molecules, are meticulously explored. Through a comprehensive physicochemical analysis of V-amylose and ulcerogenic NSAIDs, the plausibility of amylose as a protective carrier for ulcerogenic NSAIDs to gastrointestinal regions is elucidated. This review further discusses the potential therapeutic advantages of amylose-based drug delivery systems in the management of gastric ulcers. By providing controlled release kinetics and enhanced bioavailability, these systems offer promising prospects for the development of more effective ulcer therapies.

Gelatin microsphere-alginate hydrogel combined system for sustained and gastric targeted delivery of 5-fluorouracil

In the current study, novel gelatin microspheres/methacrylated alginate hydrogel combined system (5-FU-GELms/Alg-MA) was developed for gastric targeted delivery of 5-fluorouracil as an anticancer agent. While water-in-oil emulsification method was used for the production of 5-FU-GELms, Alg-MA was synthesized through methacrylation reaction occurred by epoxide ring-opening mechanism. Then, 5-FU-GELms/Alg-MA hydrogel system was fabricated by the encapsulation of 5-FU-GELms into Alg-MA hydrogel network via UV-crosslinking. To evaluate applicability of fabricated 5-FU-GELms/Alg-MA as gastric targeted drug delivery vehicle, both swelling and in vitro drug release experiments were carried out at pH 1.2 medium resembling gastric fluid. Compared to drug release directly from 5-FU-GELms, 5-FU-GELms/Alg-MA hydrogel system showed more controlled and sustained drug release profile with lower amount of cumulative release starting from early stages, since hydrogel matrix created a barrier to the diffusion of 5-FU included in microspheres. Drug release kinetic results obtained by applying various kinetic models to release data showed that the mechanism of 5-FU release from 5-FU-GELms/Alg-MA hydrogel system is controlled by Fickian diffusion. All results revealed that 5-FU-GELms/Alg-MA hydrogel integrated system could be potentially utilized as gastric targeted drug carrier to enhance therapeutic efficacy and reduce systemic side effects in gastric cancer treatments for future studies.

Using chitosan, hyaluronic acid, alginate, and gelatin-based smart biological hydrogels for drug delivery in oral mucosal lesions: A review

AIMS

Oral mucosal diseases can lead to pain, difficulty speaking and eating, psychological distress, and cancer. Topical drug delivery using biological macromolecules, specifically hydrogels, is gaining interest due to the drawbacks of conventional treatments for oral mucosal lesions.

SCOPE

Biological hydrogels made from natural polymers and their derivatives, such as chitosan, hyaluronic acid, alginate, and gelatin, represent promising alternatives to conventional oral medication delivery methods. Topical drug delivery is beneficial for oral mucosal lesions as it can directly target the affected area, especially with the development of smart stimuli-responsive hydrogels, which allow for more controlled drug release. Biological hydrogels have already been used to deliver drugs like lidocaine and nystatin. This review summarizes the current research on applying smart natural polymer-based hydrogels for drug delivery in oral mucosal lesions.

CONCLUSION

Smart biological hydrogels show great promise as topical drug delivery systems for oral mucosal lesions, offering sustained drug release, increased therapeutic efficacy, and minimized systemic complications. Technological advancement is expected to lead to the development of more effective and safer drug delivery systems. The potential benefits of biological polymer-based hydrogels make them an exciting area of research for oral mucosal lesion treatment.

A Bioartificial Pancreas with "Immune Stealth" and Continuous Oxygen Supply for Islet Transplantation

Transplantation of microencapsulated islet cells remains a promising strategy for the normalization of glucose metabolism control in type 1 diabetes mellitus. However, vigorous host immunologic rejection, fibrotic overgrowth around the microcapsules, and poor oxygen supply often lead to graft failure. Herein, a bioartificial pancreas is constructed, which incorporates the "stealth effect" based on polyethylene glycol copolymers and the high oxygen-carrying performance of fluorinated nanoparticles. Polycationic poly(l-lysine)-grafted-poly(ethylene glycol) is successfully coated on the surface of alginate microcapsules through electrostatic interaction, which can not only resist fibrinogen adhesion and avoid excessive fibrosis around the microcapsules but also isolate the host immune system from attacking, achieving a "stealth effect" of microencapsulated islet cells. Furthermore, the coloading of fluoride-based O2 nanocarriers gives them enhanced oxygen-carrying and continuous oxygen supply capabilities, thereby effectively prolonging the survival of islet cells. The intracapsular islet cells still display similar cell viability and almost normal insulin secretion function even in long-term culture under hypoxic conditions. Collectively, here a new approach is opened for microencapsulated islets to efficiently evade host immune attack and improve oxygen supply and a promising strategy is provided for islet transplantation in type 1 diabetes mellitus.

3D-printing-assisted synthesis of paclitaxel-loaded niosomes functionalized by cross-linked gelatin/alginate composite: Large-scale synthesis and in-vitro anti-cancer evaluation

Breast cancer is one of the most lethal cancers, especially in women. Despite many efforts, side effects of anti-cancer drugs and metastasis are still the main challenges in breast cancer treatment. Recently, advanced technologies such as 3D-printing and nanotechnology have created new horizons in cancer treatment. In this work, we report an advanced drug delivery system based on 3D-printed gelatin-alginate scaffolds containing paclitaxel-loaded niosomes (Nio-PTX@GT-AL). The morphology, drug release, degradation, cellular uptake, flow cytometry, cell cytotoxicity, migration, gene expression, and caspase activity of scaffolds, and control samples (Nio-PTX, and Free-PTX) were investigated. Results demonstrated that synthesized niosomes had spherical-like, in the range of 60-80 nm with desirable cellular uptake. Nio-PTX@GT-AL and Nio-PTX had a sustained drug release and were biodegradable. Cytotoxicity studies revealed that the designed Nio-PTX@GT-AL scaffold had <5 % cytotoxicity against non-tumorigenic breast cell line (MCF-10A) but showed 80 % cytotoxicity against breast cancer cells (MCF-7), which was considerably more than the anti-cancer effects of control samples. In migration evaluation (scratch-assay), approximately 70 % reduction of covered surface area was observed. The anticancer effect of the designed nanocarrier could be attributed to gene expression regulation, where a significant increase in the expression and activity of genes promoting apoptosis (CASP-3, CASP-8, and CASP-9) and inhibiting metastasis (Bax, and p53) and a remarkable decrease in metastasis-enhancing genes (Bcl2, MMP-2, and MMP-9) were observed. Also, flow cytometry results declared that Nio-PTX@GT-AL reduced necrosis and increased apoptosis considerably. The results of this study prove that employing 3D-printing and niosomal formulation is an effective approach in designing nanocarriers for efficient drug delivery applications.

In Vitro Characterizations of Post-Crosslinked Gelatin-Based Microspheres Modified by Phosphatidylcholine or Diammonium Phosphate as Antibiotic Delivery Vehicles

Hydrogel-based microspheres prepared by emulsification have been widely used as drug carriers, but biocompatibility remains a challenging issue. In this study, gelatin was used as the water phase, paraffin oil was used as the oil phase, and Span 80 was used as the surfactant. Microspheres were prepared using a water-in-oil (W/O) emulsification. Diammonium phosphate (DAP) or phosphatidylcholine (PC) were further used to improve the biocompatibility of post-crosslinked gelatin microspheres. The biocompatibility of DAP-modified microspheres (0.5-10 wt.%) was better than that of PC (5 wt.%). The microspheres soaked in phosphate-buffered saline (PBS) lasted up to 26 days before fully degrading. Based on microscopic observation, the microspheres were all spherical and hollow inside. The particle size distribution ranged from 19 μm to 22 μm in diameter. The drug release analysis showed that the antibiotic gentamicin loaded on the microspheres was released in a large amount within 2 h of soaking in PBS. It was stabilized until the amount of microspheres integrated was significantly reduced after soaking for 16 days and then released again to form a two-stage drug release curve. In vitro experiments showed that DAP-modified microspheres at concentrations less than 5 wt.% had no cytotoxicity. Antibiotic-impregnated and DAP-modified microspheres had good antibacterial effects against Staphylococcus aureus and Escherichia coli, but these drug-impregnated groups hinder the biocompatibility of hydrogel microspheres. The developed drug carrier can be combined with other biomaterial matrices to form a composite for delivering drugs directly to the affected area in the future to achieve local therapeutic effects and improve the bioavailability of drugs.