Preparation of dual-targeted redox-responsive nanogels based on pegylated sorbitan for targeted and antitumor drug delivery

Reduction-sensitive N, N'-Bis(acryloyl) cystinamide-polymerized Nanohydrogel as a Potential Nanocarrier for Paclitaxel Delivery

Novel monomer, N, N'-bis(acryloyl) cystinamide (NBACA), was designed and synthesized with L-cystine as row material. By using this NBACA both as the monomer and crosslinker, reduction-sensitive nanohydrogel was prepared in ethanol via distillation-precipitation polymerization. The obtained nanohydrogel can provide a relatively hydrophobic environment and hydrogen-bonding sites inside the gel; therefore, it is suitable for loading hydrophobic drug. When paclitaxel that possess poor water-solubility was used as a model drug, the nanohydrogel represented a high drug-loading capacity, and dispersed well in aqueous solutions. Furthermore, the disulfide-group-containing nanohydrogel exhibited good reduction-sensitive drug-release behavior. The nanohydrogel biodegraded rapidly in a reducing environment, and released approximately 80% of the PTX within 24 h. Cytotoxicity assays showed that the PTX-loaded nanohydrogel exhibited high cytotoxicity against MCF-7 breast cancer cells, while blank nanohydrogels displayed a negligible cytotoxicity.

Ultrasonic De-cross-linking of the pH- and Magneto-Responsive PHEMA/PMMA Microgel to Janus Nanoparticles: A New Synthesis Based on "Grafting from"/"Grafting to" Polymerization

Stimuli-responsive Janus nanoparticles (NPs) with a two-facial structure have been used widely in biomedical applications. Among several methods to prepare these NPs, surface-initiated atom transfer radical polymerization (SI-ATRP) has received much attention due to the precise deposition of polymers on the surface of the substrate. In this study, Janus nanoparticles with asymmetric surface chemistry were prepared through a masking method in three steps involving the covalent deposition of super paramagnetic iron oxide nanoparticles (SPIONs) on the cross-linked substrate based on methotrexate (MTX)-grafted poly(2-hydroxyethyl methacrylate) (CPM), surface functionalization of unreacted sites of immobilized SPIONs with 2-bromoisobutyryl bromide (BIBB) in order to prepare the macro-initiator (Br-Fe3O4-CPM), growing poly(methyl methacrylate) (PMMA) on the surface of the macro-initiator through the SI-ATRP method. Optical microscopy was utilized to monitor the successful modification of SPIONs. Poly(methyl methacrylate)-iron oxide-poly(2-hydroxyethyl methacrylate) (PMMA-Fe3O4-PHEMA) microgel was exposed to optimum ultrasound (US) waves to prepare the PMMA-Fe3O4-PHEMA nanoparticle. Transmission electron microscopy (TEM) was used to confirm the precise deposition of polymers and the Janus structure. The MTX release of US-synthesized Janus NPs was studied in PBS at pH values of 7.4 and 5.8. The release data were analyzed using the Excel add-in DDSolver program to evaluate the kinetics of the drug release process from the nanocarrier under different pH values.

Fabrication, characterization and optimization of berberine-loaded PLA nanoparticles using coaxial electrospray for sustained drug release

BACKGROUND

Berberine (BBR) broadly found in medicinal plants has a major application in pharmacological therapy as an anticancer drug. Clinical applications of this promising natural drug are limited due to its poor water solubility and low bioavailability.

OBJECTIVE

In this study, for the first time, we synthesized core-shell BBR-loaded PLA nanoparticles (NPBs) by using coaxial electrospray (CES) to solve the poor bioavailability of BBR.

METHODS

Three-factor (feeding rate, polymeric solution concentration and applied voltage), three-level, Box-Behnken design was used for optimization of the size and particle size distribution of the prepared NPBs.

RESULTS

Based on the results of response surface methodology, the NPBs with the mean size of 265 nm and particle size distribution of 43 nm were synthesized. A TEM image was used to well illustrate the core-shell structure of the NPBs. Encapsulation efficiency and BBR loading capacity for the optimized NPBs were determined at about 81% and 7.5%, respectively. Release of NPBs was examined at pH 7.4 and 5.8. NPBs had a slower release profile than free BBR in both pH values, and the rate of BBR release was more and faster in acidic pH than in physiological one. Effects of the NPBs on the drug release were confirmed by data fitting with six kinetic models. NPBs showed an increased cytotoxic efficacy against HCT116 cells (IC₅₀ = 56 μM), while NIH3T3 cells, non-neoplastic fibroblast cells, (IC₅₀ > 150 μM) were less affected by NPBs. Flow cytometry demonstrated that the cellular uptake of NPBs were higher than BBR at different concentrations.

CONCLUSIONS

A new approach was developed in this study to prepare NPBs using the CES process for improving the efficiency and controlled BBR release. It is concluded that nano-scaled NPBs prepared by CES can improve toxicity and chemotherapeutic properties of BBR against cancerous cells. We believe that these NPBs can exhibit further potential in cancer drug delivery systems. Graphical abstract.

Polymers and Polymer Nanocomposites for Cancer Therapy

Synthetic polymers, biopolymers, and their nanocomposites are being studied, and some of them are already used in different medical areas. Among the synthetic ones that can be mentioned are polyolefins, fluorinated polymers, polyesters, silicones, and others. Biopolymers such as polysaccharides (chitosan, hyaluronic acid, starch, cellulose, alginates) and proteins (silk, fibroin) have also become widely used and investigated for applications in medicine. Besides synthetic polymers and biopolymers, their nanocomposites, which are hybrids formed by a macromolecular matrix and a nanofiller (mineral or organic), have attracted great attention in the last decades in medicine and in other fields due to their outstanding properties. This review covers studies done recently using the polymers, biopolymers, nanocomposites, polymer micelles, nanomicelles, polymer hydrogels, nanogels, polymersomes, and liposomes used in medicine as drugs or drug carriers for cancer therapy and underlines their responses to internal and external stimuli able to make them more active and efficient. They are able to replace conventional cancer drug carriers, with better results.

Preparation of multifunctional Janus nanoparticles on the basis of SPIONs as targeted drug delivery system

Passing the Blood-Brain-Barrier (BBB) is a challenging aspect in nanomedicine. Utilizing surfactant particles is reported to be a potent strategy for easier BBB penetration. On the other hand, loading different functional molecules on a single particle is therapeutically and economically beneficial. In this study, multifunctional amphiphilic Janus nanoparticles have been prepared on the basis of superparamagnetic iron oxide nanoparticles. This Janus platform is armed with folic acid targeting agent and Doxorubicin (DOX) drug that have been conjugated on different sides of the nanoparticles. DOX has been conjugated via imine bond that makes these particles pH sensitive. Chemo-physical characters, in-vitro drug release pattern and toxicity of nanoparticles on rat C6 glioma cell line were studied that confirmed the preparation and pH-dependent behavior of nanoparticles. Microscopy observations showed the Janus morphology of nanoparticles and their cell penetration behavior. Prepared Janus nanoparticle can be utilized as a multifunctional nanomedicine platform for brain cancer treatment.

Redox-responsive nano-carriers as tumor-targeted drug delivery systems

With ever increasing scientific knowledge and awareness, research is underway around the globe to design new types of stimuli (external/internal) responsive nano-carriers for biotechnological applications at large and biomedical/pharmaceutical in particular. Based on literature evidence, stimuli-responsive carriers have been classified into four major categories, i.e. (1) physical, (2) chemical, (3) biological, and (4) dual (combination of any of the first three classes). Among various types, redox-responsive nano-carriers are of supreme interests and discussed here in this review. The difference in redox potential in tumor and normal tissue is considered as a potential target for tumor targeting leading to the development of redox-responsive drug delivery systems (DDS). In this regard, a high concentration of glutathione in tumor/intracellular environment has extensively been exploited. Disulfide bonds were found as a promising tool for designing redox-responsive which tend to cleave in a reductive environment forming sulfhydryl groups. Many nano-carriers have been explored widely to control tumor growth. These systems were used against the tumor xenograft animal model and showed improved tumor targeting with tumor growth inhibition. Herein, an effort has been made to summarize various aspects from design to development of numerous types of redox-responsive DDS including liposomes, micelles, nanoparticles, nanogel and prodrug based nanomedicines. An emphasis is also given on various types of nano-carriers with special reference to the tumor-targeted drug delivery applications. Also, dual responsive nano-carriers (in addition to redox-responsive) have also been briefly discussed. Towards the end of the chapter, the information is also given on their future perspectives.