Improved oral delivery of insulin by PLGA nanoparticles coated with 5β-cholanic acid conjugated glycol chitosan

A Comprehensive Review of Nanoparticles: From Classification to Application and Toxicity

Nanoparticles are structures that possess unique properties with high surface area-to-volume ratio. Their small size, up to 100 nm, and potential for surface modifications have enabled their use in a wide range of applications. Various factors influence the properties and applications of NPs, including the synthesis method and physical attributes such as size and shape. Additionally, the materials used in the synthesis of NPs are primary determinants of their application. Based on the chosen material, NPs are generally classified into three categories: organic, inorganic, and carbon-based. These categories include a variety of materials, such as proteins, polymers, metal ions, lipids and derivatives, magnetic minerals, and so on. Each material possesses unique attributes that influence the activity and application of the NPs. Consequently, certain NPs are typically used in particular areas because they possess higher efficiency along with tenable toxicity. Therefore, the classification and the base material in the NP synthesis hold significant importance in both NP research and application. In this paper, we discuss these classifications, exemplify most of the major materials, and categorize them according to their preferred area of application. This review provides an overall review of the materials, including their application, and toxicity.

Materials and structure of polysaccharide-based delivery carriers for oral insulin: A review

Diabetes mellitus is a chronic metabolic disease that affects >500 million patients worldwide. Subcutaneous injection of insulin is the most effective treatment at present. However, regular needle injections will cause pain, inflammation, and other adverse consequences. In recent years, significant progress has been made in non-injectable insulin preparations. Oral administration is the best way of administration due to its simplicity, convenience, and good patient compliance. However, oral insulin delivery is hindered by many physiological barriers in the gastrointestinal tract, resulting in the low relative bioavailability of direct oral insulin delivery. To improve the relative bioavailability, a variety of insulin delivery vectors have been developed. Polysaccharides are used to achieve safe and effective insulin loading due to their excellent biocompatibility and protein affinity. The functional characteristics of polysaccharide-based delivery carriers, such as pH responsiveness, mucosal adhesion, and further functionalization modifications, enhance the gastrointestinal absorption and bioavailability of insulin. This paper reviews the materials and structures of oral insulin polysaccharide-based carriers, providing ideas for further improving the relative bioavailability of oral insulin.

Eco-friendly chitosan-based nanostructures in diabetes mellitus therapy: Promising bioplatforms with versatile therapeutic perspectives

Nature-derived polymers, or biopolymers, are among the most employed materials for the development of nanocarriers. Chitosan (CS) is derived from the acetylation of chitin, and this biopolymer displays features such as biocompatibility, biodegradability, low toxicity, and ease of modification. CS-based nano-scale delivery systems have been demonstrated to be promising carriers for drug and gene delivery, and they can provide site-specific delivery of cargo. Owing to the high biocompatibility of CS-based nanocarriers, they can be used in the future in clinical trials. On the other hand, diabetes mellitus (DM) is a chronic disease that can develop due to a lack of insulin secretion or insulin sensitivity. Recently, CS-based nanocarriers have been extensively applied for DM therapy. Oral delivery of insulin is the most common use of CS nanoparticles in DM therapy, and they improve the pharmacological bioavailability of insulin. Moreover, CS-based nanostructures with mucoadhesive features can improve oral bioavailability of insulin. CS-based hydrogels have been developed for the sustained release of drugs and the treatment of DM complications such as wound healing. Furthermore, CS-based nanoparticles can mediate delivery of phytochemicals and other therapeutic agents in DM therapy, and they are promising compounds for the treatment of DM complications, including nephropathy, neuropathy, and cardiovascular diseases, among others. The surface modification of nanostructures with CS can improve their properties in terms of drug delivery and release, biocompatibility, and others, causing high attention to these nanocarriers in DM therapy.

Self-assembled chitosan-insulin oral nanoparticles - A critical perspective review

Chitosan is an abundant natural cationic polysaccharide with excellent biodegradability, bioadhesion, and biocompatibility. Chitosan is extensively researched for various particulate oral insulin drug delivery systems. Oral insulin is economically efficient and more convenient than injections, with greater patient compliance. Electrostatic ionic interaction between cationic chitosan and anionic polymer or insulin leads to the formation of spontaneously self-assembled nanoparticles. This simple technique attracted many researchers as it can be carried out quickly in mild conditions without harmful solvents, such as surfactants or chemical cross-linkers that might degrade the insulin structure. The formulated chitosan nanoparticles help to protect the core insulin from enzymatic degradation in the digestive system and improve paracellular intestinal uptake from the enterocytes due to mucoadhesion and reversible tight junction opening. Moreover, functionalized chitosan nanoparticles create newer avenues for targeted and prolonged delivery. This review focuses on modified chitosan-insulin nanoparticles and their implications on oral insulin delivery. Dependent variables and their optimal concentration ranges used in self-assembly techniques for chitosan-insulin nanoparticular synthesis are summarized. This review provides a comprehensive guide to fine-tune the essential factors to formulate stable insulin-chitosan nanoparticles using mild ionic interactions.

Progress in oral insulin delivery by PLGA nanoparticles for the management of diabetes

Currently, the only practical way to treat type 1 and advanced insulin-dependent type 2 diabetes mellitus (T1/2DM) is the frequent subcutaneous injection of insulin, which is significantly different physiologically from endogenous insulin secretion from pancreatic islets and can lead to hyperinsulinemia, pain, and infection in patients with poor compliance. Hence, oral insulin delivery has been actively pursued to revolutionize the treatment of insulin-dependent diabetes. In this review, we provide an overview of recent progress in developing poly(lactic co-glycolic acid) (PLGA) nanoparticles (NPs) for oral insulin delivery. Different strategies for insulin-loaded PLGA NPs to achieve normoglycemic effects are discussed. Finally, challenges and future perspectives of PLGA NPs for oral insulin delivery are put forward.

Biomaterials and Extracellular Vesicle Delivery: Current Status, Applications and Challenges

In this review, we will discuss the current status of extracellular vesicle (EV) delivery via biopolymeric scaffolds for therapeutic applications and the challenges associated with the development of these functionalized scaffolds. EVs are cell-derived membranous structures and are involved in many physiological processes. Naïve and engineered EVs have much therapeutic potential, but proper delivery systems are required to prevent non-specific and off-target effects. Targeted and site-specific delivery using polymeric scaffolds can address these limitations. EV delivery with scaffolds has shown improvements in tissue remodeling, wound healing, bone healing, immunomodulation, and vascular performance. Thus, EV delivery via biopolymeric scaffolds is becoming an increasingly popular approach to tissue engineering. Although there are many types of natural and synthetic biopolymers, the overarching goal for many tissue engineers is to utilize biopolymers to restore defects and function as well as support host regeneration. Functionalizing biopolymers by incorporating EVs works toward this goal. Throughout this review, we will characterize extracellular vesicles, examine various biopolymers as a vehicle for EV delivery for therapeutic purposes, potential mechanisms by which EVs exert their effects, EV delivery for tissue repair and immunomodulation, and the challenges associated with the use of EVs in scaffolds.

From Static to Dynamic: A Review on the Role of Mucus Heterogeneity in Particle and Microbial Transport

Mucus layers (McLs) are on the front line of the human defense system that protect us from foreign abiotic/biotic particles (e.g., airborne virus SARS-CoV-2) and lubricates our organs. Recently, the impact of McLs on human health (e.g., nutrient absorption and drug delivery) and diseases (e.g., infections and cancers) has been studied extensively, yet their mechanisms are still not fully understood due to their high variety among organs and individuals. We characterize these variances as the heterogeneity of McLs, which lies in the thickness, composition, and physiology, making the systematic research on the roles of McLs in human health and diseases very challenging. To advance mucosal organoids and develop effective drug delivery systems, a comprehensive understanding of McLs' heterogeneity and how it impacts mucus physiology is urgently needed. When the role of airway mucus in the penetration and transmission of coronavirus (CoV) is considered, this understanding may also enable a better explanation and prediction of the CoV's behavior. Hence, in this Review, we summarize the variances of McLs among organs, health conditions, and experimental settings as well as recent advances in experimental measurements, data analysis, and model development for simulations.

Controlled synthesis of in-situ gold nanoparticles onto chitosan functionalized PLGA nanoparticles for oral insulin delivery

Chitosan-based nanoparticles (chitosan nanoparticles (ChNps), chitosan gold Nps (ChAuNps), and chitosan gold Nps functionalized with poly lactic-co-glycolic acid (PLGA) (ChAuNps/PLGA)) were prepared as nanocarriers for insulin to improve its oral uptake. The emulsion solvent diffusion method was employed to functionalize the Nps with PLGA. TEM, SEM, DLS, and zeta potential were conducted to characterize the Nps. The morphological analysis confirmed the formation of spherical Nps with hydrodynamic particle sizes of 138±23, 16±2.2, and 50±9.3 nm for ChNps, ChAuNps, and ChAuNps/PLGA, respectively. Zeta potential measurements indicated two types of Nps, regardless of insulin entrapment, positively charged, (ChNps (+36 ± 4.2, +31 ± 2.2mv)) and ChAuNps (+37 ± 4.3, +33 ± 2.5mv) and negatively charged (ChAuNps/PLGA (-31 ± 2.7, -26 ± 2.1 mv)). The in vitro studies were assessed by measuring the entrapment efficiencies (EE%) and the release profiles of insulin at different pH values. EE% for ChNps, ChAuNps, and ChAuNps/PLGA were 97 ± 1.5, 98.4 ± 1.9, and 99 ± 1.2%, respectively. At an acidic medium, a significant level of insulin retention was observed (96 ± 0.08%) for ChAuNps/PLGA. While a high amount was released at higher pH values over an extended period of time. In vivo studies, diabetic rats treated with insulin-loaded Nps had reduced blood glucose level (BGL) (38 ± 2.8, 35 ± 6.5, and 27 ± 5.6%) for ChNps ChAuNps and ChAuNps/PLGA, respectively. The pharmacological availability (PA%) and bioavailability (FR%) for insulin-loaded ChAuNps/PLGA were 15.8 ± 0.71% and 7.7 ± 0.93%, respectively. Altogether, emphasize the role of biocompatible Nps and their efficiency in the convenient delivery of insulin, thus lowering the BGL in a safe condition.

Interactions between Nanoparticles and Intestine

The use of nanoparticles (NPs) has surely grown in recent years due to their versatility, with a spectrum of applications that range from nanomedicine to the food industry. Recent research focuses on the development of NPs for the oral administration route rather than the intravenous one, placing the interactions between NPs and the intestine at the centre of the attention. This allows the NPs functionalization to exploit the different characteristics of the digestive tract, such as the different pH, the intestinal mucus layer, or the intestinal absorption capacity. On the other hand, these same characteristics can represent a problem for their complexity, also considering the potential interactions with the food matrix or the microbiota. This review intends to give a comprehensive look into three main branches of NPs delivery through the oral route: the functionalization of NPs drug carriers for systemic targets, with the case of insulin carriers as an example; NPs for the delivery of drugs locally active in the intestine, for the treatment of inflammatory bowel diseases and colon cancer; finally, the potential concerns and side effects of the accidental and uncontrolled exposure to NPs employed as food additives, with focus on E171 (titanium dioxide) and E174 (silver NPs).