Polyester-based nanoparticles for nucleic acid delivery

Biodegradable polyester-based nano drug delivery system in cancer chemotherapy: a review of recent progress (2021-2023)

Cancer presents a formidable threat to human health, with the majority of cases currently lacking a complete cure. Frequently, chemotherapy drugs are required to impede its progression. However, these drugs frequently suffer from drawbacks such as poor selectivity, limited water solubility, low bioavailability, and a propensity for causing organ toxicity. Consequently, a concerted effort has been made to seek improved drug delivery systems. Nano-drug delivery systems based on biodegradable polyesters have emerged as a subject of widespread interest in this pursuit. Extensive research has demonstrated their potential for offering high bioavailability, effective encapsulation, controlled release, and minimal toxicity. Notably, poly (ε-caprolactone) (PCL), poly (lactic-co-glycolic acid) (PLGA), and polylactic acid (PLA) have gained prominence as the most widely utilized options as carriers of the nano drug delivery system. This paper comprehensively reviews recent research on these materials as nano-carriers for delivering chemotherapeutic drugs, summarizing their latest advancements, acknowledging their limitations, and forecasting future research directions.

Promising Gene Delivery Properties of Polycations Based on 2-(N,N-dimethylamino)ethyl Methacrylate and Polyethylene Glycol Monomethyl Ether Methacrylate Copolymers

Cationic copolymers based on 2-(N,N-dimethylamino)ethyl methacrylate and polyethylene glycol monomethyl ether (pDMAEMA-co-PEO) with different molecular weights have been synthesized. Their physicochemical properties were studied by NMR spectroscopy, sedimentation, and potentiometric titration. According to the data of potentiometric titration for the synthesized pegylated cationic copolymers, the apparent dissociation constants were determined in the pH range from 4.5 to 8.5. The physicochemical properties of interpolyelectrolyte complexes of these polycations with circular DNA (IPEC DNA) were also studied by dynamic light scattering, electrophoretic mobility, and TEM methods. It has been established that the diameter and electrokinetic potential (ζ-potential) of interpolyelectrolyte complexes can be varied over a wide range (from 200 nm to 1.5 μm and from -25 mV to +30 mV) by changing the ratio of oppositely charged ionizable groups in pegylated cationic copolymers and DNA, as well as by regulating medium pH. The resistance of the IPEC DNA/polycation complex to the action of nucleases was studied by electrophoresis in agarose gel; the cytotoxic effect of the polymers in vitro, and the efficiency of penetration (transfection) of IPEC DNA with PDMAEMA-co-PEO-polycations into eukaryotic cells of a cell line derived from human embryonic kidneys HEK 293 in vitro.

Biomedical applications of nanomaterials in the advancement of nucleic acid therapy: Mechanistic challenges, delivery strategies, and therapeutic applications

In the past few decades, substantial advancement has been made in nucleic acid (NA)-based therapies. Promising treatments include mRNA, siRNA, miRNA, and anti-sense DNA for treating various clinical disorders by modifying the expression of DNA or RNA. However, their effectiveness is limited due to their concentrated negative charge, instability, large size, and host barriers, which make widespread application difficult. The effective delivery of these medicines requires safe vectors that are efficient & selective while having non-pathogenic qualities; thus, nanomaterials have become an attractive option with promising possibilities despite some potential setbacks. Nanomaterials possess ideal characteristics, allowing them to be tuned into functional bio-entity capable of targeted delivery. In this review, current breakthroughs in the non-viral strategy of delivering NAs are discussed with the goal of overcoming challenges that would otherwise be experienced by therapeutics. It offers insight into a wide variety of existing NA-based therapeutic modalities and techniques. In addition to this, it provides a rationale for the use of non-viral vectors and a variety of nanomaterials to accomplish efficient gene therapy. Further, it discusses the potential for biomedical application of nanomaterials-based gene therapy in various conditions, such as cancer therapy, tissue engineering, neurological disorders, and infections.

Biomaterial-based gene therapy

Gene therapy, a medical approach that involves the correction or replacement of defective and abnormal genes, plays an essential role in the treatment of complex and refractory diseases, such as hereditary diseases, cancer, and rheumatic immune diseases. Nucleic acids alone do not easily enter the target cells due to their easy degradation in vivo and the structure of the target cell membranes. The introduction of genes into biological cells is often dependent on gene delivery vectors, such as adenoviral vectors, which are commonly used in gene therapy. However, traditional viral vectors have strong immunogenicity while also presenting a potential infection risk. Recently, biomaterials have attracted attention for use as efficient gene delivery vehicles, because they can avoid the drawbacks associated with viral vectors. Biomaterials can improve the biological stability of nucleic acids and the efficiency of intracellular gene delivery. This review is focused on biomaterial-based delivery systems in gene therapy and disease treatment. Herein, we review the recent developments and modalities of gene therapy. Additionally, we discuss nucleic acid delivery strategies, with a focus on biomaterial-based gene delivery systems. Furthermore, the current applications of biomaterial-based gene therapy are summarized.

Biocompatibility and Antimicrobial Activity of Electrospun Fibrous Materials Based on PHB and Modified with Hemin

The effect of the hemin (Hmi) on the structure and properties of nanocomposite electrospun materials based on poly-3-hydroxybutyrate (PHB) is discussed in the article. The additive significantly affected the morphology of fibers allowed to produce more elastic material and provided high antimicrobial activity. The article considers also the impact of the hemin on the biocompatibility of the nonwoven material based on PHB and the prospects for wound healing.

The Advancement of Biodegradable Polyesters as Delivery Systems for Camptothecin and Its Analogues-A Status Report

Camptothecin (CPT) has demonstrated antitumor activity in lung, ovarian, breast, pancreas, and stomach cancers. However, this drug, like many other potent anticancer agents, is extremely water-insoluble. Furthermore, pharmacology studies have revealed that prolonged schedules must be administered continuously. For these reasons, several of its water-soluble analogues, prodrugs, and macromolecular conjugates have been synthesized, and various formulation approaches have been investigated. Biodegradable polyesters have gained popularity in cancer treatment in recent years. A number of biodegradable polymeric drug delivery systems (DDSs), designed for localized and systemic administration of therapeutic agents, as well as tumor-targeting macromolecules, have entered clinical trials, demonstrating the importance of biodegradable polyesters in cancer therapy. Biodegradable polyester-based DDSs have the potential to deliver the payload to the target while also increasing drug availability at intended site. The systemic toxicity and serious side-effects associated with conventional cancer therapies can be significantly reduced with targeted polymeric systems. This review elaborates on the use of biodegradable polyesters in the delivery of CPT and its analogues. The design of various DDSs based on biodegradable polyesters has been described, with the drug either adsorbed on the polymer's surface or encapsulated within its macrostructure, as well as those in which a hydrolyzed chemical bond is formed between the active substance and the polymer chain. The data related to the type of DDSs, the kind of linkage, and the details of in vitro and in vivo studies are included.

Nanoparticles in Endodontics Disinfection: State of the Art

Endodontic-related diseases constitute the fourth most expensive pathologies in industrialized countries. Specifically, endodontics is the part of dentistry focused on treating disorders of the dental pulp and its consequences. In order to treat these problems, especially endodontic infections, dental barriers and complex root canal anatomy should be overcome. This constitutes an unmet medical need since the rate of successful disinfection with the currently marketed drugs is around 85%. Therefore, nanoparticles constitute a suitable alternative in order to deliver active compounds effectively to the target site, increasing their therapeutic efficacy. Therefore, in the present review, an overview of dental anatomy and the barriers that should be overcome for effective disinfection will be summarized. In addition, the versatility of nanoparticles for drug delivery and their specific uses in dentistry are comprehensively discussed. Finally, the latest findings, potential applications and state of the art nanoparticles with special emphasis on biodegradable nanoparticles used for endodontic disinfection are also reviewed.

Redox-Responsive Disulfide Cyclic Peptides: A New Strategy for siRNA Delivery

RNA interference (RNAi) is a powerful tool capable of targeting virtually any protein without time-consuming and expensive drug development studies. However, due to obstacles facing efficient and safe delivery, RNAi-based therapeutic approach remains a challenge. Herein, we have designed and synthesized a number of disulfide-constraining cyclic and hybrid peptides using tryptophan and arginine residues. Our hypothesis was that peptide structures would undergo reduction by intracellular glutathione (more abundant in cancer cells) and unpack the small interfering RNA (siRNA) from the peptide/siRNA complexes. A subset of newly developed peptides (specifically, C4 and H4) exhibited effective cellular internalization of siRNA (∼70% of the cell population; monitored by flow cytometry and confocal microscopy), the capability of protecting siRNA against early degradation by nucleases (monitored by gel electrophoresis), minimal cytotoxicity in selected cell lines (studied by cell viability and LC₅₀ calculations), and efficient protein silencing by 70-75% reduction in the expression of targeting signal transducer and activator of transcription 3 (STAT3) in human triple-negative breast cancer (TNBC) MDA-MB-231 cells, analyzed using the Western blot technique. Our results indicate the birth of a promising new family of siRNA delivery systems that are capable of safe and efficient delivery, even in the presence of nucleases.

Development of a novel rapamycin loaded nano- into micro-formulation for treatment of lung inflammation

It has recently emerged that drugs such as the mTOR inhibitor rapamycin (Rapa) may play a key role in the treatment of airway inflammation associated with lung diseases, such as chronic obstructive pulmonary disease, asthma, and cystic fibrosis. Nevertheless, Rapa clinical application is still prevented by its unfavorable chemical-physical properties, limited oral bioavailability, and adverse effects related to non-specific biodistribution. In this paper, the design and production of a novel formulation of Rapa based on nano into micro (NiM) particles are detailed. To achieve it, Rapa-loaded nanoparticles were produced by nanoprecipitation of an amphiphilic pegylated poly-ɛ-caprolactone/polyhydroxyethyl aspartamide graft copolymer. The obtained nanoparticles that showed a drug loading of 14.4 wt% (corresponding to an encapsulation efficiency of 82 wt%) did not interact with mucins and were able to release and protect Rapa from degradation in simulated lung and cell fluids. To allow their local administration to the lungs as a dry powder, particle engineering at micro-sized level was done by embedding nanoparticles into mannitol-based microparticles by spray drying. Obtained NiM particles had a mean diameter of about 2-µ, spherical shape and had good potential to be delivered to the lungs by a breath-activated dry powder inhalers. Rheological and turbidity experiments showed that these NiM particles can dissolve in lung simulated fluid and deliver the Rapa-loaded pegylated nanoparticles, which can diffuse through the mucus layer.

In-depth drug delivery to tumoral soft tissues via pH responsive hydrogel

A pH responsive nanoparticle–hydrogel hybrid drug delivery system was investigated for in-depth anticancer drug delivery to solid tumours. It consists of acid susceptible polymer nanoparticles loaded in a chitosan hydrogel. The hybrid formulation was characterized by UV-visible spectroscopy, FTIR, SEM, TEM, particle size analysis, zeta potential measurement and viscosity measurement. Drug encapsulation and nanoparticle loading efficiencies were found to be 48% and 72% respectively which describes the efficient interaction of the chemical entities in this hybrid drug delivery system. The hydrogel exhibited pH responsive behaviour: minimal drug and nanoparticle release at physiological pH but an increase in viscosity under acidic conditions and fast nanoparticle and drug release. The cytotoxicity of the drug loaded hydrogel was investigated against the MCF-7 breast cancer cell line along with the drug and nanoparticles without hydrogel. The drug loaded hydrogel showed a better cytotoxic effect on MCF-7 cancer cells. Thus, drug loaded nanoparticles containing hydrogel could be a better option for maximum drug distribution in tumours.

A pH responsive nanoparticle–hydrogel hybrid drug delivery system was investigated for in-depth anticancer drug delivery to solid tumours.

Green and sustainable synthesis of poly(δ-valerolactone) with a TBD catalyzed ring-opening polymerization reaction

A green and sustainable method is proposed for the TBD catalyzed ring-opening polymerization of δ-valerolactone.

Exosome membrane-modified M2 macrophages targeted nanomedicine: Treatment for allergic asthma

BACKGROUNDS

Exosomes are naturally secreted nanovesicles that have emerged as a promising therapeutic nanodelivery platform due to their specific composition, biological properties, and stability. Modifying synthetic nanoparticles with the intrinsic hallmarks of exosome membrane to create exosome mimetics could lead to safe and efficient smart silencer delivery.

OBJECTIVES

The study focuses on exploring the combination of polylactic-co-glycolic acid (PLGA)-based nanoparticles with naturally occurring exosome membrane from M2 macrophages to deliver a Dnmt3aos smart silencer to treat allergic asthma (AA) in mice.

MATERIALS AND METHODS

Exosome membrane of M2 macrophages and PLGA nanoparticles (PLGA NPs) wrapped with the smart silencer of Dnmt3aos (Dnmt3aos^{smart silencer}) were first synthesized. The resulting exosome membrane coated PLGA@Dnmt3aos^{smart silencer} (EM-PLGA@Dnmt3aos^{smart silencer}) was administered intravenously into Der f1-induced asthma mice, which was followed by the investigation of therapeutic outcomes and the mechanism in vivo.

RESULTS

Seven infusions of EM-PLGA@Dnmt3aos^{smart silencer} ameliorated AA with a marked reduction of lung inflammation. After intravenous injection, the EM-PLGA@Dnmt3aos^{smart silencer} was distributed in various organs, including the lungs, with retention over 48 h, and it targeted M2 macrophages. Moreover, the injections of EM-PLGA@Dnmt3aos^{smart silencer} markedly decreased the proportion of M2 macrophages and inflammatory cytokines in the airway. More importantly, the EM-PLGA@Dnmt3aos^{smart silencer} treatment did not obviously suppress the overall immune function of host.

CONCLUSION

To our knowledge, this study provides the first experimental evidence of the ability of EM-PLGA@Dnmt3aos^{smart silencer} to target M2 macrophages in the treatment of AA by combining exosome membrane and biomaterials, thus presenting a novel immunotherapy for the allergic disease.

Recent Advances and Challenges in Gene Delivery Mediated by Polyester-Based Nanoparticles

Gene therapy is a promising approach for the treatment of several diseases, such as chronic or viral infections, inherited disorders, and cancer. The cellular internalization of exogenous nucleic acids (NA) requires efficient delivery vehicles to overcome their inherent pharmacokinetic drawbacks, e.g. electrostatic repulsions, enzymatic degradation, limited cellular uptake, fast clearance, etc. Nanotechnological advancements have enabled the use of polymer-based nanostructured biomaterials as safe and effective gene delivery systems, in addition to viral vector delivery methods. Among the plethora of polymeric nanoparticles (NPs), this review will provide a comprehensive and in-depth summary of the polyester-based nanovehicles, including poly(lactic-co-glycolic acid) (PLGA) and polylactic acid (PLA) NPs, used to deliver a variety of foreign NA, e.g. short interfering RNA (siRNA), messenger RNA (mRNA), and plasmid DNA (pDNA). The article will review the versatility of polyester-based nanocarriers including their recent application in the delivery of the clustered, regularly-interspaced, short palindromic repeats/Cas (CRISPR/Cas) genome editing system for treating gene-related diseases. The remaining challenges and future trend of the targeted delivery of this revolutionary genome-editing system will be discussed. Special attention will be given to the pivotal role of nanotechnology in tackling emerging infections such as coronavirus disease 2019 (COVID-19): ground-breaking mRNA vaccines delivered by NPs are currently used worldwide to fight the pandemic, pushing the boundaries of gene therapy.

Particle engineering principles and technologies for pharmaceutical biologics

The global market of pharmaceutical biologics has expanded significantly during the last few decades. Currently, pharmaceutical biologic products constitute an indispensable part of the modern medicines. Most pharmaceutical biologic products are injections either in the forms of solutions or lyophilized powders because of their low oral bioavailability. There are certain pharmaceutical biologic entities formulated into particulate delivery systems for the administration via non-invasive routes or to achieve prolonged pharmaceutical actions to reduce the frequency of injections. It has been well documented that the design of nano- and microparticles via various particle engineering technologies could render pharmaceutical biologics with certain benefits including improved stability, enhanced intracellular uptake, prolonged pharmacological effect, enhanced bioavailability, reduced side effects, and improved patient compliance. Herein, we review the principles of the particle engineering technologies based on bottom-up approach and present the important formulation and process parameters that influence the critical quality attributes with some mathematical models. Subsequently, various nano- and microparticle engineering technologies used to formulate or process pharmaceutical biologic entities are reviewed. Lastly, an array of commercialized products of pharmaceutical biologics accomplished based on various particle engineering technologies are presented and the challenges in the development of particulate delivery systems for pharmaceutical biologics are discussed.

Poly(anhydride-ester) gemcitabine: Synthesis and particle engineering of a high payload hydrolysable polymeric drug for cancer therapy

Gemcitabine (GMT) is a nucleoside analog used in the treatment of a variety of solid tumors. GMT was chemically modified with a hydrolysable linker, and subsequently incorporated into a poly(anhydride-ester) backbone via melt-polymerization, with the active antimetabolite GMT, thus, becoming the repeat unit that makes up this new material, a biodegradable polymer. Characterization of the structure of polymeric GMT (polyGMT) revealed the incorporation of an average 26 molecules of GMT per polymer chain, which corresponds to a drug loading of 58%w/w. The glass transition temperature of the formed polyGMT was determined to be 123 °C. PolyGMT was engineered into nanoparticles (NPs) using a dialysis-based method, with a resulting geometric diameter of 206 ± 38 nm. The particles are easily dispersible and stable in aqueous-based media, with a hydrodynamic diameter of 229 ± 28 nm. The prepared hydrolysable polyGMT NPs demonstrate ultra-long release profile due to the hydrophobic nature of the linker, and as per characteristic erosion behavior of polymers with anhydride-ester bonds. Accelerated in vitro release studies demonstrate the recovery of free GMT upon hydrolysis, with biological activity as assessed by cytotoxicity assays performed in adenocarcinoma human alveolar basal epithelial (A549) and highly metastatic murine osteosarcoma (K7M2) cells lines. The characteristics of polyGMT, including its thermal properties and built in hydrolysable structure, are thus conducive for use in the preparation of drug delivery systems. Engineered structures prepared with polyGMT can maintain their morphology at ambient and physiologically relevant conditions, and free GMT is recovered as the anhydride and ester bonds are hydrolyzed. This work is innovative as for the first time we demonstrate the ability to polymerize GMT in a hydrolysable polymer structure, and engineer NPs of this polymeric chemotherapy. The synthetic strategy allows for tuning of the polymer hydrophobicity and thus potentialize its behavior, including degradation profile, by varying the linker chemistry. Such controlled release hydrolysable polymers with very high drug loading and controlled erosion profiles are relevant as they may offer new opportunities in drug delivery applications for the treatment of malignant neoplasms.

Polymeric nanoparticles for RNA delivery

As exemplified by recent clinical approval of RNA drugs including the latest COVID-19 mRNA vaccines, RNA therapy has demonstrated great promise as an emerging medicine. Central to the success of RNA therapy is the delivery of RNA molecules into the right cells at the right location. While the clinical success of nanotechnology in RNA therapy has been limited to lipid-based nanoparticles currently, polymers, due to their tunability and robustness, have also evolved as a class of promising material for the delivery of various therapeutics including RNAs. This article overviews different types of polymers used in RNA delivery and the methods for the formulation of polymeric nanoparticles and highlights recent progress of polymeric nanoparticle-based RNA therapy.

Nano-soldiers Ameliorate Silibinin Delivery: A Review Study

Flavonoids are a large group of naturally occurring compounds, which are of interest due to their great pharmacological effects and health-promoting impacts. These properties have led to their extensive application in a variety of pathological conditions, particularly cancer. Flavonoids are used in large quantities in a human's daily diet and a high amount of flavonoids are found in the intestine after oral usage. However, flavonoid concentrations in tissue/plasma are low because of their low bioavailability, the leading to the low efficacy of flavonoids in different clinical disorders. For this reason, nanotechnology application for delivering flavonoids to tumor sites has recently received significant attention. Silibinin is a key member of flavonoids and a bioactive component of silymarin, which is widely isolated from Silybum marianum. This plant-derived chemical has a number of valuable biological and therapeutic activities such as antioxidant, anti-inflammatory, neuroprotective, anti-tumor, hepatoprotective, cardioprotective and anti-diabetic. These beneficial effects have been demonstrated in in vivo and in vitro experiments. However, it seems that silibinin has a variety of limitations and poor bioavailability is the most important factor restricting its wide application. Hence, there have been attempts to improve the bioavailability of silibinin and it has been suggested that nano-soldiers are potential candidates for this aim. In the present review, we describe the different drug delivery systems for improving the bioavailability of silibinin.

Poly(3-Hydroxybutyrate)-Based Nanoparticles for Sorafenib and Doxorubicin Anticancer Drug Delivery

Dual drug-loaded nanotherapeutics can play an important role against the drug resistance and side effects of the single drugs. Doxorubicin and sorafenib were efficiently co-encapsulated by tailor-made poly([R,S]-3-hydroxybutyrate) (PHB) using an emulsion-solvent evaporation method. Subsequent poly(ethylene glycol) (PEG) conjugation onto nanoparticles was applied to make the nanocarriers stealth and to improve their drug release characteristics. Monodisperse PHB-sorafenib-doxorubicin nanoparticles had an average size of 199.3 nm, which was increased to 250.5 nm after PEGylation. The nanoparticle yield and encapsulation efficiencies of drugs decreased slightly in consequence of PEG conjugation. The drug release of the doxorubicin was beneficial, since it was liberated faster in a tumor-specific acidic environment than in blood plasma. The PEG attachment decelerated the release of both the doxorubicin and the sorafenib, however, the release of the latter drug remained still significantly faster with increased initial burst compared to doxorubicin. Nevertheless, the PEG-PHB copolymer showed more beneficial drug release kinetics in vitro in comparison with our recently developed PEGylated poly(lactic-co-glycolic acid) nanoparticles loaded with the same drugs.

Biocompatible Polymers Combined with Cyclodextrins: Fascinating Materials for Drug Delivery Applications

Cyclodextrins (CD) are a group of cyclic oligosaccharides with a cavity/specific structure that enables to form inclusion complexes (IC) with a variety of molecules through non-covalent host-guest interactions. By an elegant combination of CD with biocompatible, synthetic and natural polymers, different types of universal drug delivery systems with dynamic/reversible properties have been generated. This review presents the design of nano- and micro-carriers, hydrogels, and fibres based on the polymer/CD supramolecular systems highlighting their possible biomedical applications. Application of the most prominent hydrophobic aliphatic polyesters that exhibit biodegradability, represented by polylactide and polycaprolactone, is described first. Subsequently, particular attention is focused on materials obtained from hydrophilic polyethylene oxide. Moreover, examples are also presented for grafting of CD on polysaccharides. In summary, we show the application of host-guest interactions in multi-component functional biomaterials for controlled drug delivery.

Research and development of drug delivery systems based on drug transporter and nano-formulation

In recent years, the continuous occurrence of multi-drug resistance in the clinic has made people pay more attention to the transporter. Changes in the expression and activity of transporters can cause corresponding changes in drug pharmacokinetics and pharmacodynamics. The drug-drug interactions (DDI) caused by transporters can seriously affect drug effectiveness and toxicity. In the development of pharmaceutical preparations, people have increasingly concerned about the effects and regulation of transporters in drug effects. To improve the targeting and physicochemical properties of drugs, the development of targeted agents is very rapid. Among them, novel nano-formulations are the best. With the continuous innovation and development of nano-formulation, its application has become more and more extensive. Nano-formulation has exerted certain advantages in the drug development based on transporters, and is also involved in the combination of targeted transporters. This review focuses on the application of novel nano-agents targeting transporters and the introduction of drug-transporter-based nano-formulations.

Aberrantly expressed microRNAs and their implications in childhood central nervous system tumors

Even though the treatment of childhood cancer has evolved significantly in recent decades, aggressive central nervous system (CNS) tumors are still a leading cause of morbidity and mortality in this population. Consequently, the identification of molecular targets that can be incorporated into diagnostic practice, effectively predict prognosis, follow treatment response, and materialize into potential targeted therapeutic approaches are still warranted. Since the first evidence of the participation of miRNAs in cancer development and progression 20 years ago, notable progress has been made in the basic understanding of the contribution of their dysregulation as epigenetic driver of tumorigenesis. Nevertheless, among the plethora of articles in the literature, microRNA profiling of pediatric tumors are scarce. This article gives an overview of the recent advances in the diagnostic/prognostic potential of miRNAs in a selection of pediatric CNS tumors: medulloblastoma, ependymoma, pilocytic astrocytoma, glioblastoma, diffuse intrinsic pontine glioma, atypical teratoid/rhabdoid tumors, and choroid plexus tumors.

Silencing KLK12 expression via RGDfC-decorated selenium nanoparticles for the treatment of colorectal cancer in vitro and in vivo

Short interfering RNA (siRNA) has been investigated as a promising modality of cancer treatment due to its capability to target specific target genes for downregulation. However, the successful application of this strategy depends on producing a safe and effective carrier system for delivering siRNA to the tumor. Thus, investigation of siRNA delivery carriers is a fundamental step in the field of siRNA-based therapeutics. In the current research, the surface of selenium nanoparticles (SeNPs) were modified with the tumor-targeted molecular RGDfC peptide with positive charge to synthetize the biocompatible siRNA carrier RGDfC-SeNPs. Subsequently, KLK12-siRNA was loaded onto the surface of RGDfC-SeNPs to create functionalized nanoparticles (RGDfC-Se@siRNA) that we tested for in vitro and in vivo antitumor efficacy. We measured significantly greater particle uptake in HT-29 colorectal cancer cells relative to HUVECs, providing evidence for the targeted delivery of RGDfC-Se@siRNA. We found that RGDfC-Se@siRNA could enter HT-29 cells primarily via clathrin-mediated endocytosis. Further, these particles experienced faster siRNA release in an acidic microenvironment compared to pH 7.4. The results from quantitative PCR and Western blot assays suggested that the target gene of KLK12 in HT-29 cells were obviously silenced by RGDfC-Se@siRNA. The further biological studies showed that treatment with RGDfC-Se@siRNA had ability to suppress the proliferation and migration/invasion of HT-29 cells, and triggered HT-29 cells apoptosis. RGDfC-Se@siRNA could induce the mitochondrial membrane potential (MMP) disruption and enhance the reactive oxygen species (ROS) generation in HT-29 cells, indicating that RGDfC-Se@siRNA induced the HT-29 cells apoptosis possibly by a ROS-mediated mitochondrial dysfunction pathway. Importantly, the in vivo antitumor study also verified that RGDfC-Se@siRNA could significantly suppress the growth of tumor in vivo. In addition, we did not observe any signs of systemic or tissue-specific toxicity after administration of RGDfC-Se@siRNA in mice. As a whole, these findings suggest that RGDfC-Se@siRNA has promising potential as a therapy for colorectal cancer.

Dendrimers as Pharmaceutical Excipients: Synthesis, Properties, Toxicity and Biomedical Applications

The European Medicines Agency (EMA) and the Current Good Manufacturing Practices (cGMP) in the United States of America, define excipient as the constituents of the pharmaceutical form other than the active ingredient, i.e., any component that is intended to furnish pharmacological activity. Although dendrimers do not have a pharmacopoeia monograph and, therefore, cannot be recognized as a pharmaceutical excipient, these nanostructures have received enormous attention from researchers. Due to their unique properties, like the nanoscale uniform size, a high degree of branching, polyvalency, aqueous solubility, internal cavities, and biocompatibility, dendrimers are ideal as active excipients, enhancing the solubility of poorly water-soluble drugs. The fact that the dendrimer's properties are controllable during their synthesis render them promising agents for drug-delivery applications in several pharmaceutical formulations. Additionally, dendrimers can be used for reducing the drug toxicity and for the enhancement of the drug efficacy. This review aims to discuss the properties that turn dendrimers into pharmaceutical excipients and their potential applications in the pharmaceutical and biomedical fields.

Self-assembled amphiphilic copolymers as dual delivery system for immunotherapy

Subunit vaccines using recombinant antigens appear as the privileged vaccination technology for safety reasons but still require the development of carriers/adjuvants ensuring optimal immunogenicity and efficacy. Micelles from self-assembled amphiphilic copolymers have recently emerged as highly relevant and promising candidates owing to their ease of preparation, low size (entering in lymphatic capillaries for reaching lymph nodes), size/surface tunability and chemical versatility enabling introduction of stimuli (e.g. pH) responsive features and biofunctionalization with dedicated molecules. In particular, research efforts have increasingly focused on dendritic cells (DCs) targeting and activation by co-delivering (with antigen) ligands of pattern recognition receptors (PRRs, e.g. toll-like receptors). Such strategy has appeared as one of the most effective for eliciting CD 8+ T-cell response, which is crucial in the eradication of tumors and numerous infectious diseases. In this short review, we highlight the recent advances in such micelle-based carriers in subunit vaccination and how their precise engineering can be a strong asset for guiding and controlling immune responses.

Small interfering RNAs (siRNAs) in cancer therapy: a nano-based approach

Cancer is one of the most complex diseases that has resulted in multiple genetic disorders and cellular abnormalities. Globally, cancer is the most common health concern disease that is affecting human beings. Great efforts have been made over the past decades in biology with the aim of searching novel and more efficient tools in therapy. Thus, small interfering RNAs (siRNAs) have been considered one of the most noteworthy developments which are able to regulate gene expression following a process known as RNA interference (RNAi). RNAi is a post-transcriptional mechanism that involves the inhibition of gene expression through promoting cleavage on a specific area of a target messenger RNA (mRNA). This technology has shown promising therapeutic results for a good number of diseases, especially in cancer. However, siRNA therapeutics have to face important drawbacks in therapy including stability and successful siRNA delivery in vivo. In this regard, the development of effective siRNA delivery systems has helped addressing these issues by opening novel therapeutic windows which have allowed to build up important advances in Nanomedicine. In this review, we discuss the progress of siRNA therapy as well as its medical application via nanoparticle-mediated delivery for cancer treatment.

Kinetic study of TBD catalyzed δ-valerolactone polymerization using a gas-driven droplet flow reactor

The reaction kinetics of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) catalyzed δ-valerolactone polymerization was determined using a gas-driven droplet reactor.