Bifunctional Succinylated ε-Polylysine-Coated Mesoporous Silica Nanoparticles for pH-Responsive and Intracellular Drug Delivery Targeting the Colon

The stomach, small intestine, and colon-specific gastrointestinal tract delivery systems for bioactive nutrients

Oral administration is a convenient way to deliver bioactive nutrients. However, the complex and dynamic environment of the gastrointestinal (GI) tract poses distinct challenges. These include the acidic environment of the stomach, limited transport across the GI mucosa, and the risk of enzymatic degradation, all of which can compromise the nutritional effectiveness of orally delivered nutrients. In response to these challenges, various GI tract delivery systems have been developed to target specific regions, such as the stomach, small intestine, or colon, to precisely control the release of bioactive nutrients and enhance their health-promoting benefits. This review critically examines the principles underlying stomach-, small intestine-, and colon-targeted delivery systems, highlighting the selection of appropriate wall materials and the interactions between delivery systems and the mucosal epithelial barrier. Moreover, we describe relevant biological models and quantitative analyses to measure these interactions. In particular, we emphasize the significant advantages offered by colon-targeted delivery systems in maintaining a healthy colonic microenvironment. This review aims to inspire novel concepts and stimulate further research into GI tract delivery systems, offering promising avenues for maximizing the therapeutic effects of bioactive nutrients in practical applications.

Nanomedicine innovations in colon and rectal cancer: advances in targeted drug and gene delivery systems

Nanotechnology has revolutionized cancer diagnostics and therapy, offering unprecedented possibilities to overcome the constraints of conventional treatments. This study provides a detailed overview of the current progress and difficulties in the creation of nanostructured materials, with a specific emphasis on their use in drug and gene delivery systems. The study examines tactics that attempt to improve the effectiveness and safety of chemotherapeutic drugs such as doxorubicin (Dox) by focusing on the potential of antibody-drug conjugates and functionalized nanoparticles. Moreover, it clarifies the challenges encountered in administering nanoparticles orally for gastrointestinal treatments, emphasizing the crucial physicochemical properties that affect their behavior in the gastrointestinal system. This study highlights the transformational potential of nanostructured materials in precision oncology by examining advanced breakthroughs such cell membrane-camouflaged nanoparticles and inorganic nanoparticles designed for gastrointestinal disorders. The text investigates the processes involved in the absorption of nanoparticles and their destruction in lysosomes, revealing the many methods in which enterocytes take up these particles. This study strongly supports the use of advanced nanoparticle-based methods to reduce the harmful effects on the whole body and improve the effectiveness of therapy, based on a thorough examination of current experiments on animals and humans. The main objective of this paper is to provide a fundamental comprehension that will stimulate more investigation and practical use in the field of cancer nanomedicine, advancing its boundaries.

Nanoparticle-Based Drug Delivery Systems for Inflammatory Bowel Disease Treatment

Inflammatory bowel disease (IBD) is a chronic, non-specific inflammatory condition characterized by recurring inflammation of the intestinal mucosa. However, the existing IBD treatments are ineffective and have serious side effects. The etiology of IBD is multifactorial and encompasses immune, genetic, environmental, dietary, and microbial factors. The nanoparticles (NPs) developed based on specific targeting methodologies exhibit great potential as nanotechnology advances. Nanoparticles are defined as particles between 1 and 100 nm in size. Depending on their size and surface functionality, NPs exhibit different properties. A variety of nanoparticle types have been employed as drug carriers for the treatment of inflammatory bowel disease (IBD), with encouraging outcomes observed in experimental models. They increase the bioavailability of drugs and enable targeted drug delivery, promoting localized treatment and thus enhancing efficacy. Nevertheless, numerous challenges persist in the translation from nanomedicine to clinical application, including enhanced formulations and preparation techniques, enhanced drug safety profiles, and so forth. In the future, it will be necessary for scientists and clinicians to collaborate in order to study disease mechanisms, develop new drug delivery strategies, and screen new nanomedicines. Nevertheless, numerous challenges persist in the translation from nanomedicine to clinical application, including enhanced formulations and preparation techniques, enhanced drug safety profiles, and so forth. In the future, it will be necessary for scientists and clinicians to collaborate in order to study disease mechanisms, develop new drug delivery strategies, and screen new nanomedicines.

Eco-Friendly Fungal Chitosan-Silica Dual-Shell Microcapsules with Tailored Mechanical and Barrier Properties for Potential Consumer Product Applications

Commercial perfume microcapsules are becoming popular across the globe to fulfill consumers' demands. However, most of microcapsules rely on synthetic polymers and/or animal-sourced ingredients to form the shells. Therefore, replacement of the shell materials is imperative to minimize environmental microplastic pollution, as well as to meeting peoples' needs, religious beliefs, and lifestyles. Herein, we report a methodology to fabricate environmentally benign dual-shell (fungal chitosan-SiO2) microcapsules laden with fragrance oil (hexyl salicylate). Anionically stabilized oil droplets were coated with fungal chitosan via interfacial electrostatic interactions at pH 2, which were then covered by an inorganic coating of SiO2 produced via external alkaline mineralization of sodium silicate. Core-shell microcapsules with a spherical morphology were achieved. Under compression, dual-shell chitosan-SiO2 microcapsules yielded a mean nominal rupture stress of 3.0 ± 0.2 MPa, which was significantly higher than that of single-shell microcapsules (1.7 ± 0.2 MPa). After 20 days in neutral pH water, only ∼2.5% of the oil was released from dual-shell microcapsules, while single-shell microcapsules cumulatively released more than 10%. These findings showed that the additional SiO2 coating significantly enhanced both mechanical and barrier properties of microcapsules, which may be appealing for multiple commercial applications, including cosmetics and detergents.

Silica nanoparticle design for colorectal cancer treatment: Recent progress and clinical potential

Colorectal cancer (CRC) is the third most common cancer worldwide and the second most common cause of cancer death. Nanotherapies are able to selectively target the delivery of cancer therapeutics, thus improving overall antitumor efficiency and reducing conventional chemotherapy side effects. Mesoporous silica nanoparticles (MSNs) have attracted the attention of many researchers due to their remarkable advantages and biosafety. We offer insights into the recent advances of MSNs in CRC treatment and their potential clinical application value.

Advances in peptide-based drug delivery systems

Drug delivery systems (DDSs) are designed to deliver drugs to their specific targets to minimize their toxic effects and improve their susceptibility to clearance during targeted transport. Peptides have high affinity, low immunogenicity, simple amino acid composition, and adjustable molecular size; therefore, most peptides can be coupled to drugs via linkers to form peptide-drug conjugates (PDCs) and act as active pro-drugs. PDCs are widely thought to be promising DDSs, given their ability to improve drug bio-compatibility and physiological stability. Peptide-based DDSs are often used to deliver therapeutic substances such as anti-cancer drugs and nucleic acid-based drugs, which not only slow the degradation rate of drugs in vivo but also ensure the drug concentration at the targeted site and prolong the half-life of drugs in vivo. This article provides an profile of the advancements and future development in functional peptide-based DDSs both domestically and internationally in recent years, in the expectation of achieving targeted drug delivery incorporating functional peptides and taking full advantage of synergistic effects.

Potential Applications and Additive Manufacturing Technology-Based Considerations of Mesoporous Silica: A Review

Nanoporous materials are categorized as microporous (pore sizes 0.2-2 nm), mesoporous (pore sizes 2-50 nm), and macroporous (pore sizes 50-1000 nm). Mesoporous silica (MS) has gained a significant interest due to its notable characteristics, including organized pore networks, specific surface areas, and the ability to be integrated in a variety of morphologies. Recently, MS has been widely accepted by range of manufacturer and as drug carrier. Moreover, silica nanoparticles containing mesopores, also known as mesoporous silica nanoparticles (MSNs), have attracted widespread attention in additive manufacturing (AM). AM commonly known as three-dimensional printing is the formalized rapid prototyping (RP) technology. AM techniques, in comparison to conventional methods, aid in reducing the necessity for tooling and allow versatility in product and design customization. There are generally several types of AM processes reported including VAT polymerization (VP), powder bed fusion (PBF), sheet lamination (SL), material extrusion (ME), binder jetting (BJ), direct energy deposition (DED), and material jetting (MJ). Furthermore, AM techniques are utilized in fabrication of various classified fields such as architectural modeling, fuel cell manufacturing, lightweight machines, medical, and fabrication of drug delivery systems. The review concisely elaborates on applications of mesoporous silica as versatile material in fabrication of various AM-based pharmaceutical products with an elaboration on various AM techniques to reduce the knowledge gap.

Responsive nanosystems for targeted therapy of ulcerative colitis: Current practices and future perspectives

The pharmacological approach to treating gastrointestinal diseases is suffering from various challenges. Among such gastrointestinal diseases, ulcerative colitis manifests inflammation at the colon site specifically. Patients suffering from ulcerative colitis notably exhibit thin mucus layers that offer increased permeability for the attacking pathogens. In the majority of ulcerative colitis patients, the conventional treatment options fail in controlling the symptoms of the disease leading to distressing effects on the quality of life. Such a scenario is due to the failure of conventional therapies to target the loaded moiety into specific diseased sites in the colon. Targeted carriers are needed to address this issue and enhance the drug effects. Conventional nanocarriers are mostly readily cleared and have nonspecific targeting. To accumulate the desired concentration of the therapeutic candidates at the inflamed area of the colon, smart nanomaterials with responsive nature have been explored recently that include pH responsive, reactive oxygen species responsive (ROS), enzyme responsive and thermo - responsive smart nanocarrier systems. The formulation of such responsive smart nanocarriers from nanotechnology scaffolds has resulted in the selective release of therapeutic drugs, avoiding systemic absorption and limiting the undesired delivery of targeting drugs into healthy tissues. Recent advancements in the field of responsive nanocarrier systems have resulted in the fabrication of multi-responsive systems i.e. dual responsive nanocarriers and derivitization that has increased the biological tissues and smart nanocarrier's interaction. In addition, it has also led to efficient targeting and significant cellular uptake of the therapeutic moieties. Herein, we have highlighted the latest status of the responsive nanocarrier drug delivery system, its applications for on-demand delivery of drug candidates for ulcerative colitis, and the prospects are underpinned.

Bioactive glass in the treatment of ulcerative colitis to regulate the TLR4 / MyD88 / NF-κB pathway

Ulcerative colitis (UC) is a chronic and recurrent intestinal disease of unknown aetiology, and the few treatments approved for UC have serious side effects. In this study, a new type of uniformly monodispersed calcium-enhanced radial mesoporous micro-nano bioactive glass (HCa-MBG) was prepared for UC treatment. We established cellular and rat UC models to explore the effects and mechanism of HCa-MBG and traditional BGs (45S5, 58S) on UC. The results showed that BGs significantly reduced the cellular expression of several inflammatory factors, such as IL-1β, IL-6, TNF-α and NO. In the animal experiments, BGs were shown to repair the DSS-damaged colonic mucosa. Moreover, BGs downregulated the mRNA levels of the inflammatory factors IL-1β, IL-6, TNF-α and iNOS, which were stimulated by DSS. BGs were also found to manage the expression of key proteins in NF-kB signal pathway. However, HCa-MBG was more effective than traditional BGs in terms of improving UC clinical manifestations and reducing the expression of inflammatory factors in rats. This study confirmed for the first time that BGs can be used as an adjuvant drug in UC treatment, thereby preventing UC progression.

Surface design of nanocarriers: Key to more efficient oral drug delivery systems

As nanocarriers (NCs) can improve the solubility of drugs, prevent their degradation by gastrointestinal (GI) enzymes and promote their transport across the mucus gel layer and absorption membrane, the oral bioavailability of these drugs can be substantially enhanced. All these properties of NCs including self-emulsifying drug delivery systems (SEDDS), solid lipid nanoparticles (SLNs), nanostructured lipid carriers (NLCs), liposomes, polymeric nanoparticles, inorganic nanoparticles and polymeric micelles depend mainly on their surface chemistry. In particular, interaction with food, digestive enzymes, bile salts and electrolytes, diffusion behaviour across the mucus gel layer and fate on the absorption membrane are determined by their surface. Bioinert surfaces limiting interactions with gastrointestinal fluid and content as well as with mucus, adhesive surfaces providing an intimate contact with the GI mucosa and absorption enhancing surfaces can be designed. Furthermore, charge converting surfaces shifting their zeta potential from negative to positive directly at the absorption membrane and surfaces providing a targeted drug release are advantageous. In addition to these passive surfaces, even active surfaces cleaving mucus glycoproteins on their way through the mucus gel layer can be created. Within this review, we provide an overview on these different surfaces and discuss their impact on the performance of NCs in the GI tract.

Multifunctional hydrogels based on chitosan, hyaluronic acid and other biological macromolecules for the treatment of inflammatory bowel disease: A review

Hydrogel is a three-dimensional network polymer material rich in water. It is widely used in the biomedical field because of its unique physical and chemical properties and good biocompatibility. In recent years, the incidence of inflammatory bowel disease (IBD) has gradually increased, and the disadvantages caused by traditional drug treatment of IBD have emerged. Therefore, there is an urgent need for new treatments to alleviate IBD. Hydrogel has become a potential therapeutic platform. However, there is a lack of comprehensive review of functional hydrogels for IBD treatment. This paper first summarizes the pathological changes in IBD sites. Then, the action mechanisms of hydrogels prepared from chitosan, sodium alginate, hyaluronic acid, functionalized polyethylene glycol, cellulose, pectin, and γ-polyglutamic acid on IBD were described from aspects of drug delivery, peptide and protein delivery, biologic therapies, loading probiotics, etc. In addition, the advanced functions of IBD treatment hydrogels were summarized, with emphasis on adhesion, synergistic therapy, pH sensitivity, particle size, and temperature sensitivity. Finally, the future development direction of IBD treatment hydrogels has been prospected.

Protein succinylation associated with the progress of hepatocellular carcinoma

Although post‐translational modification is critical to tumorigenesis, how succinylation modification of lysine sites influences hepatocellular carcinoma (HCC) remains obscure. 90 tumours and paired adjacent normal tissue of liver cancer were enrolled for succinylation staining. 423 HCC samples with 20 genes related to succinylation modification from TCGA were downloaded for model construction. Statistical methods were employed to analyse the data, including the Non‐Negative Matrix Factorization (NMF) algorithm, t‐Distributed Stochastic Neighbour Embedding (t‐SNE) algorithm, and Cox regression analysis. The staining pan‐succinyllysine antibody staining indicated that tumour tissues had a higher succinyllysine level than adjacent tissues (p < 0.001), which could be associated with a worse prognosis (p = 0.02). The survival was associated with pathological stage, tumour recurrence status and succinyllysine intensity in the univariate or multivariable cox survival analysis model. The risk model from 20 succinyllysine‐related genes had the best prognosis prediction. The high expression of succinylation modification in HCC contributed to the worse patient survival prognosis. Model construction of 20 genes related to succinylation modification (MEAF6, OXCT1, SIRT2, CREBBP, KAT5, SIRT4, SIRT6, SIRT7, CPT1A, GLYATL1, SDHA, SDHB, SDHC, SDHD, SIRT1, SIRT3, SIRT5, SUCLA2, SUCLG1 and SUCLG2) could be reliable in predicting prognosis in HCC.

Colonic Delivery of Nutrients for Sustained and Prolonged Release of Gut Peptides: A Novel Strategy for Appetite Management

Obesity is one of the major global threats to human health and risk factors for cardiometabolic diseases and certain cancers. Glucagon-like peptide-1 (GLP-1) plays a major role in appetite and glucose homeostasis and recently the USFDA approved GLP-1 agonists for the treatment of obesity and type 2 diabetes. GLP-1 is secreted from enteroendocrine L-cells in the distal part of the gastrointestinal (GI) tract in response to nutrient ingestion. Endogenously released GLP-1 has a very short half-life of <2 min and most of the nutrients are absorbed before reaching the distal GI tract and colon, which hinders the use of nutritional compounds for appetite regulation. The review article focuses on nutrients that endogenously stimulate GLP-1 and peptide YY (PYY) secretion via their receptors in order to decrease appetite as preventive action. In addition, various delivery technologies such as pH-sensitive, mucoadhesive, time-dependent, and enzyme-sensitive systems for colonic targeting of nutrients delivery are described. Sustained colonic delivery of nutritional compounds could be one of the most promising approaches to prevent obesity and associated metabolic diseases by, e.g., sustained GLP-1 release.

Novel Drug and Gene Delivery System and Imaging Agent Based on Marine Diatom Biosilica Nanoparticles

Mesoporous silica nanoparticles (MSNs) have great potential for applications as a drug delivery system (DDS) due to their unique properties such as large pore size, high surface area, biocompatibility, biodegradability, and stable aqueous dispersion. The MSN-mediated DDS can carry chemotherapeutic agents, optical sensors, photothermal agents, short interfering RNA (siRNA), and gene therapeutic agents. The MSN-assisted imaging techniques are applicable in cancer diagnosis. However, their synthesis via a chemical route requires toxic chemicals and is challenging, time-consuming, and energy-intensive, making the process expensive and non-viable. Fortunately, nature has provided a viable alternative material in the form of biosilica from marine resources. In this review, the applications of biosilica nanoparticles synthesized from marine diatoms in the field of drug delivery, biosensing, imaging agents, and regenerative medicine, are highlighted. Insights into the use of biosilica in the field of DDSs are elaborated, with a focus on different strategies to improve the physico-chemical properties with regards to drug loading and release efficiency, targeted delivery, and site-specific binding capacity by surface functionalization. The limitations, as well as the future scope to develop them as potential drug delivery vehicles and imaging agents, in the overall therapeutic management, are discussed.

Silica nanoparticles: Biomedical applications and toxicity

Silica nanoparticles (SiNPs) are composed of silicon dioxide, the most abundant compound on Earth, and are used widely in many applications including the food industry, synthetic processes, medical diagnosis, and drug delivery due to their controllable particle size, large surface area, and great biocompatibility. Building on basic synthetic methods, convenient and economical strategies have been developed for the synthesis of SiNPs. Numerous studies have assessed the biomedical applications of SiNPs, including the surface and structural modification of SiNPs to target various cancers and diagnose diseases. However, studies on the in vitro and in vivo toxicity of SiNPs remain in the exploratory stage, and the toxicity mechanisms of SiNPs are poorly understood. This review covers recent studies on the biomedical applications of SiNPs, including their uses in drug delivery systems to diagnose and treat various diseases in the human body. SiNP toxicity is discussed in terms of the different systems of the human body and the individual organs in those systems. This comprehensive review includes both fundamental discoveries and exploratory progress in SiNP research that may lead to practical developments in the future.

Influence of Critical Parameters on Cytotoxicity Induced by Mesoporous Silica Nanoparticles

Mesoporous Silica Nanoparticles (MSNs) have received increasing attention in biomedical applications due to their tuneable pore size, surface area, size, surface chemistry, and thermal stability. The biocompatibility of MSNs, although generally believed to be satisfactory, is unclear. Physicochemical properties of MSNs, such as diameter size, morphology, and surface charge, control their biological interactions and toxicity. Experimental conditions also play an essential role in influencing toxicological results. Therefore, the present study includes studies from the last five years to statistically analyse the effect of various physicochemical features on MSN-induced in-vitro cytotoxicity profiles. Due to non-normally distributed data and the presence of outliers, a Kruskal-Wallis H test was conducted on different physicochemical characteristics, including diameter sizes, zeta-potential measurements, and functionalisation of MSNs, based on the viability results, and statistical differences were obtained. Subsequently, pairwise comparisons were performed using Dunn's procedure with a Bonferroni correction for multiple comparisons. Other experimental parameters, such as type of cell line used, cell viability measurement assay, and incubation time, were also explored and analysed for statistically significant results.

pH-Responsive Self-Assembling Peptide-Based Biomaterials: Designs and Applications

Stimuli-responsive peptide-based biomaterials are increasingly gaining interest for various specific and targeted treatments, including drug delivery and tissue engineering. Among all stimuli, pH can be especially useful because endogenous pH changes are often associated with abnormal microenvironments. pH-Responsive amino acids and organic linkers can be easily incorporated into peptides that self-assemble into various nanostructures. Thus, these largely biocompatible and easily tunable platforms are ideal candidates for drug release and as fibrous materials capable of mimicking the native extracellular matrix. In this review, we highlight common design motifs and mechanisms of pH-responsiveness in self-assembling peptide-based biomaterials, focusing on recent advances of these biomaterials applied in drug delivery and tissue engineering. Finally, we suggest future challenges and areas for potential development in pH-responsive self-assembling peptide-based biomaterials.

Enhancing the efficacy of albendazole for liver cancer treatment using mesoporous silica nanoparticles: an in vitro study

The present study aimed to synthesize albendazole (ABZ)-loaded Mobil Composition of Matter No. 41 (MCM-41 NPs) to increase the efficacy of the drug against liver cancer. ABZ was loaded into MCM-41 NPs, and after in vitro characterization, such as size, size distribution, zeta potential, morphology, chemical composition, thermal profile, drug release, surface and pore volume, and pore size, their biological effects were evaluated using 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) cell migration assays. The results demonstrated that monodispersed and spherical NPs with a size of 220 ± 11.5 and 293 ± 8.7 nm, for MCM-41 NPs and ABZ-loaded MCM-41 NPs, respectively, and drug loading efficiency of 30 % were synthesized. ABZ was loaded physically into MCM-41 NPs, leading to a decrease in surface volume, pore size, and pore volume. Also, MCM-41 NPs could increase the cytotoxicity effects of ABZ by 2.9-fold (IC₅₀ = 23 and 7.9 µM for ABZ and ABZ-loaded MCM-41 NPs, respectively). In addition, both ABZ and ABZ-loaded MCM-41 NPs could restrain the cell migration by 12 %. Overall, the results of the present study suggest evaluating the potency of MCM-41 NPs, as a potent nanoplatform, for ABZ delivery in vivo environment.

See also the Graphical Abstract(Fig. 1).

Advances in the treatment of inflammatory bowel disease: Focus on polysaccharide nanoparticulate drug delivery systems

The complex pathogenesis of inflammatory bowel disease (IBD) explains the several hurdles for finding an efficient approach to cure it. Nowadays, therapeutic protocols aim to reduce inflammation during the hot phase or maintain remission during the cold phase. Nonetheless, these drugs suffer from severe side effects or poor efficacy due to low bioavailability in the inflamed region of the intestinal tract. New protocols based on antibodies that target proinflammatory cytokines are clinically relevant. However, besides being expensive, their use is associated with a primary nonresponse or a loss of response following a long administration period. Accordingly, many researchers exploited the physiological changes of the mucosal barrier for designing nanoparticulate drug delivery systems to target inflamed tissues. Others exploited biocompatibility and relative affordability of polysaccharides to test their intrinsic anti-inflammatory and healing properties in IBD models. This critical review updates state of the art on advances in IBD treatment. Data on using polysaccharide nanoparticulate drug delivery systems for IBD treatment are reviewed and discussed.

Glucose sensitive konjac glucomannan/concanavalin A nanoparticles as oral insulin delivery system

Compared with injection, oral drug delivery is a better mode of administration because of its security, low pain and simplicity. Insulin is the first choice for clinical treatment of type 1 diabetes, but, because insulin inability to resist gastrointestinal (GI) digestion results in poor oral bioavailability of insulin. Herein, we developed a targeted oral delivery system for diabetes. ConA-INS-KGM nanoparticles were prepared, loaded with insulin, fabricated from konjac glucomannan (KGM) and concanavalin A (ConA) through a crosslinking method, as an insulin oral delivery system in response to different blood glucose levels. The size of nanoparticles was characterized by TEM, which showed that these nanoparticles were formed spherical particles with a diameter of about 500 nm. In vitro release of insulin from these nanoparticles was studied, which indicated that insulin release is reversible at different glucose concentrations. In vivo tests demonstrated that they are safe and have high biocompatibility. Using the nanoparticles to treat diabetic mice, we found that they can control blood sugar levels for 6 h, retaining their glucose-sensitive properties during this time. Therefore, these nanoparticles have significant potential as glucose-responsive systems for diabetes and show great applications in biomedical fields.

Advanced Delivery Systems Based on Lysine or Lysine Polymers

Polylysine and materials that integrate lysine form promising drug delivery platforms. As a cationic macromolecule, a polylysine polymer electrostatically interacts with cells and is efficiently internalized, thereby enabling intracellular delivery. Although polylysine is intrinsically pH-responsive, the conjugation with different functional groups imparts smart, stimuli-responsive traits by adding pH-, temperature-, hypoxia-, redox-, and enzyme-responsive features for enhanced delivery of therapeutic agents. Because of such characteristics, polylysine has been used to deliver various cargos such as small-molecule drugs, genes, proteins, and imaging agents. Furthermore, modifying contrast agents with polylysine has been shown to improve performance, including increasing cellular uptake and stability. In this review, the use of lysine residues, peptides, and polymers in various drug delivery systems has been discussed comprehensively to provide insight into the design and robust manufacturing of lysine-based delivery platforms.

Application of Non-Viral Vectors in Drug Delivery and Gene Therapy

Vectors and carriers play an indispensable role in gene therapy and drug delivery. Non-viral vectors are widely developed and applied in clinical practice due to their low immunogenicity, good biocompatibility, easy synthesis and modification, and low cost of production. This review summarized a variety of non-viral vectors and carriers including polymers, liposomes, gold nanoparticles, mesoporous silica nanoparticles and carbon nanotubes from the aspects of physicochemical characteristics, synthesis methods, functional modifications, and research applications. Notably, non-viral vectors can enhance the absorption of cargos, prolong the circulation time, improve therapeutic effects, and provide targeted delivery. Additional studies focused on recent innovation of novel synthesis techniques for vector materials. We also elaborated on the problems and future research directions in the development of non-viral vectors, which provided a theoretical basis for their broad applications.

Orally Administrable Therapeutic Nanoparticles for the Treatment of Colorectal Cancer

Colorectal cancer (CRC) is one of the most common and lethal human malignancies worldwide; however, the therapeutic outcomes in the clinic still are unsatisfactory due to the lack of effective and safe therapeutic regimens. Orally administrable and CRC-targetable drug delivery is an attractive approach for CRC therapy as it improves the efficacy by local drug delivery and reduces systemic toxicity. Currently, chemotherapy remains the mainstay modality for CRC therapy; however, most of chemo drugs have low water solubility and are unstable in the gastrointestinal tract (GIT), poor intestinal permeability, and are susceptible to P-glycoprotein (P-gp) efflux, resulting in limited therapeutic outcomes. Orally administrable nanoformulations hold the great potential for improving the bioavailability of poorly permeable and poorly soluble therapeutics, but there are still limitations associated with these regimes. This review focuses on the barriers for oral drug delivery and various oral therapeutic nanoparticles for the management of CRC.

Microfluidic assembly of pomegranate-like hierarchical microspheres for efflux regulation in oral drug delivery

Herein, a multi-functional nano-in-micro hierarchical microsphere system is demonstrated for controlling the intestinal efflux pumps that affect the oral bioavailability of many therapeutic drugs. The hierarchical particles were generated by a co-flow microfluidic device and consisted of porous silica nanoparticles packed in Eudragit® polymeric matrix. Meropenem (MER), a last-resort antibacterial drug, was loaded into porous silica (MCM-48) with a loading capacity of 34.3 wt%. In this unique materials combination, MCM-48 enables ultrahigh loading of a hydrophilic MER, while the Eudragit® polymers not only protect MER from gastric pH but also act as an antagonist for p-glycoprotein protein efflux pumps to reduce the efflux of MER back into the gastrointestinal lumen. We investigated the in-vitro temporal MER release and bidirectional (absorptive and secretory) drug permeation model across the Caco-2 monolayer. The bioavailability of MER was significantly improved by all of the prepared formulations (i.e. increased absorptive transport and reduced secretory transport). The Eudragit® RSPO formulated MER-MCM showed the best performance with an efflux ratio (i.e. secretory transport/absorptive transport) of 0.35, which is 7.4 folds less than pure MER (2.62). Lastly, the prepared formulations were able to retain the antibacterial activity of MER against Staphylococcus aureus and Pseudomonas aeruginosa. STATEMENT OF SIGNIFICANCE: Meropenem (MER) is a last resort antibiotic used for the treatment of drug-resistant and acute infections and only available as intravenous injectable dosage due to its poor chemical and thermal stability, and ultra-poor oral bioavailability because of the efflux action of P-glycoprotein (P-gp) pumps. Multifunctional colloidal micro/nanoparticles can help to solve these issues. Herein, we designed pomegranate-like hierarchical microspheres comprised of porous silica nanoparticles and enteric Eudragit® polymers (Eudragit®S100, Eudragit®RSPO, and Eudragit®RS100) using a co-flow microfluidic device. Our formulations allow for ultrahigh loading of hydrophilic MER, protects MER from gastric pH, and also block P-gp efflux pumps for enhanced MER permeation/retention with Eudragit®RSPO - showing 13.9-folds higher permeation and 7.4-folds reduction in efflux ratio in a bi-directional Caco-2 monolayer culture system.

Bi-functionalized aminoguanidine-PEGylated periodic mesoporous organosilica nanoparticles: a promising nanocarrier for delivery of Cas9-sgRNA ribonucleoproteine

BACKGROUND

There is a great interest in the efficient intracellular delivery of Cas9-sgRNA ribonucleoprotein complex (RNP) and its possible applications for in vivo CRISPR-based gene editing. In this study, a nanoporous mediated gene-editing approach has been successfully performed using a bi-functionalized aminoguanidine-PEGylated periodic mesoporous organosilica (PMO) nanoparticles (RNP@AGu@PEG1500-PMO) as a potent and biocompatible nanocarrier for RNP delivery.

RESULTS

The bi-functionalized MSN-based nanomaterials have been fully characterized using electron microscopy (TEM and SEM), nitrogen adsorption measurements, thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), and dynamic light scattering (DLS). The results confirm that AGu@PEG1500-PMO can be applied for gene-editing with an efficiency of about 40% as measured by GFP gene knockdown of HT1080-GFP cells with no notable change in the morphology of the cells.

CONCLUSIONS

Due to the high stability and biocompatibility, simple synthesis, and cost-effectiveness, the developed bi-functionalized PMO-based nano-network introduces a tailored nanocarrier that has remarkable potential as a promising trajectory for biomedical and RNP delivery applications.

Targeting strategies of oral nano-delivery systems for treating inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic relapsing inflammatory disorder of gastrointestinal tract with rising incidence. Established treatments of IBD are characterized by significantly adverse effects, insufficient therapeutic efficacy. Employing the oral nano-drug delivery systems for targeted therapy is capable of effectively avoiding systematic absorption and increasing local drug concentration, consequently leading to decreased adverse effects and improved therapeutic outcomes. This review gives a brief profile of pathophysiological considerations in terms of developing disease-directed drug delivery systems, then focuses on mechanisms and strategies of current oral nano-drug delivery systems, including size-, enzyme-, redox-, pH-, ligand-receptor-, mucus-dependent systems, and proposes the future directions of managements for IBD.

Ophthalmic Drops with Nanoparticles Derived from a Natural Product for Treating Age-Related Macular Degeneration

There is a continuing, urgent need for an ophthalmic (eye) drop for the clinical therapy of age-related macular degeneration (AMD), a leading cause of blindness. Here, we report the first formulation of an eye drop that is effective via autophagy for AMD treatment. This eye drop is based on a single natural product derivative (ACD), which is an amphiphilic molecule containing a 6-aminohexanoate group (H₂N(CH₂)₅COO-). We demonstrate that this eye drop reverses the abnormal angiogenesis induced in a primate model of AMD that has the pathological characteristics close to that of human AMD. The ACD molecule was self-assembled in an aqueous environment leading to nanoparticles (NPs) about 9.0 nm in diameter. These NPs were encapsulated in calcium alginate hydrogel. The resulting eye drop effectively slowed the release of ACD and displayed extended release periods in both simulated blood (pH 7.4) and inflammatory (pH 5.2) environments. We show that the eye drop penetrated both the corneal and blood-eye barriers and reached the fundus. With low cellular toxicity, the drop targeted S1,25D₃-membrane-associated rapid response steroid-binding protein (1,25D₃-MARRS) promoting autophagy in a dose-dependent manner. In addition, the drop inhibited cell migration and tubular formation. On the other hand, when protein 1,25D₃-MARRS was knocked down, the eye drop did not exhibit such inhibition functionalities. Our study indicates that the 6-aminohexanoate group on self-assembled NPs encapsulated in hydrogel leads to the positive in vivo outcomes. The present formulation offers a promising approach for clinical treatment of human AMD.

Application of a Scavenger Receptor A1-Targeted Polymeric Prodrug Platform for Lymphatic Drug Delivery in HIV

We have developed a macromolecular prodrug platform based on poly(l-lysine succinylated) (PLS) that targets scavenger receptor A1 (SR-A1), a receptor expressed by myeloid and endothelial cells. We demonstrate the selective uptake of PLS by murine macrophage, RAW 264.7 cells, which was eliminated upon cotreatment with the SR-A inhibitor polyinosinic acid (poly I). Further, we observed no uptake of PLS in an SR-A1-deficient RAW 264.7 cell line, even after 24 h incubation. In mice, PLS distributed to lymphatic organs following i.v. injection, as observed by ex vivo fluorescent imaging, and accumulated in lymph nodes following both i.v. and i.d. administrations, based on immunohistochemical analysis with high-resolution microscopy. As a proof-of-concept, the HIV antiviral emtricitabine (FTC) was conjugated to the polymer's succinyl groups via ester bonds, with a drug loading of 14.2% (wt/wt). The prodrug (PLS-FTC) demonstrated controlled release properties in vitro with a release half-life of 15 h in human plasma and 29 h in esterase-inhibited plasma, indicating that drug release occurs through both enzymatic and nonenzymatic mechanisms. Upon incubation of PLS-FTC with human peripheral blood mononuclear cells (PBMCs), the released drug was converted to the active metabolite FTC triphosphate. In a pharmacokinetic study in rats, the prodrug achieved ∼7-19-fold higher concentrations in lymphatic tissues compared to those in FTC control, supporting lymphatic-targeted drug delivery. We believe that the SR-A1-targeted macromolecular PLS prodrug platform has extraordinary potential for the treatment of infectious diseases.

Stimulus-Responsive Nanomedicines for Disease Diagnosis and Treatment

Stimulus-responsive drug delivery systems generally aim to release the active pharmaceutical ingredient (API) in response to specific conditions and have recently been explored for disease treatments. These approaches can also be extended to molecular imaging to report on disease diagnosis and management. The stimuli used for activation are based on differences between the environment of the diseased or targeted sites, and normal tissues. Endogenous stimuli include pH, redox reactions, enzymatic activity, temperature and others. Exogenous site-specific stimuli include the use of magnetic fields, light, ultrasound and others. These endogenous or exogenous stimuli lead to structural changes or cleavage of the cargo carrier, leading to release of the API. A wide variety of stimulus-responsive systems have been developed-responsive to both a single stimulus or multiple stimuli-and represent a theranostic tool for disease treatment. In this review, stimuli commonly used in the development of theranostic nanoplatforms are enumerated. An emphasis on chemical structure and property relationships is provided, aiming to focus on insights for the design of stimulus-responsive delivery systems. Several examples of theranostic applications of these stimulus-responsive nanomedicines are discussed.

Influence of the Surface Functionalization on the Fate and Performance of Mesoporous Silica Nanoparticles

Mesoporous silica nanoparticles have been broadly applied as drug delivery systems owing to their exquisite features, such as excellent textural properties or biocompatibility. However, there are various biological barriers that prevent their proper translation into the clinic, including: (1) lack of selectivity toward tumor tissues, (2) lack of selectivity for tumoral cells and (3) endosomal sequestration of the particles upon internalization. In addition, their open porous structure may lead to premature drug release, consequently affecting healthy tissues and decreasing the efficacy of the treatment. First, this review will provide a comprehensive and systematic overview of the different approximations that have been implemented into mesoporous silica nanoparticles to overcome each of such biological barriers. Afterward, the potential premature and non-specific drug release from these mesoporous nanocarriers will be addressed by introducing the concept of stimuli-responsive gatekeepers, which endow the particles with on-demand and localized drug delivery.

Smart Protein-Based Formulation of Dendritic Mesoporous Silica Nanoparticles: Toward Oral Delivery of Insulin

Oral insulin administration still represents a paramount quest that almost a century of continuous research attempts did not suffice to fulfill. Before pre-clinical development, oral insulin products have first to be optimized in terms of encapsulation efficiency, protection against proteolysis, and intestinal permeation ability. With the use of dendritic mesoporous silica nanoparticles (DMSNs) as an insulin host and together with a protein-based excipient, succinylated β-lactoglobulin (BL), pH-responsive tablets permitted the shielding of insulin from early release/degradation in the stomach and mediated insulin permeation across the intestinal cellular membrane. Following an original in vitro cellular assay based on insulin starvation, direct cellular fluorescent visualization has evidenced how DMSNs could ensure the intestinal cellular transport of insulin.

Basics to advances in nanotherapy of colorectal cancer

Colorectal cancer (CRC) is the third most common cancer existing across the globe. It begins with the formation of polyps leading to the development of metastasis, especially in advanced stage patients, who necessitate intensive chemotherapy that usually results in a poor response and high morbidity owing to multidrug resistance and severe untoward effects to the non-cancerous cells. Advancements in the targeted drug delivery permit the targeting of tumor cells without affecting the non-tumor cells. Various nanocarriers such as liposomes, polymeric nanoparticles, carbon nanotubes, micelles, and nanogels, etc. are being developed and explored for effective delivery of cytotoxic drugs to the target site thereby enhancing the drug distribution and bioavailability, simultaneously subduing the side effects. Moreover, immunotherapy for CRC is being explored for last few decades. Few clinical trials have even potentially benefited patients suffering from CRC, still immunotherapy persists merely an experimental alternative. Assessment of the ongoing and completed trials is to be warranted for effective treatment of CRC. Scientists are paying efforts to develop novel carrier systems that may enhance the targeting potential of low therapeutic index chemo- and immune-therapeutics. Several preclinical studies have revealed the superior efficacy of nanotherapy in CRC as compared to conventional approaches. Clinical trials are being recruited to ascertain the safety and efficacy of CRC therapies. The present review discourses in a nutshell the molecular interventions including the genetics, signaling pathways involved in CRC, and advances in various strategies explored for the treatment of CRC with a special emphasis on nanocarriers based drug targeting.