Polyurethane/doxorubicin nanoparticles based on electrostatic interactions as pH-sensitive drug delivery carriers

Advancements in nanoscale delivery systems: optimizing intermolecular interactions for superior drug encapsulation and precision release

Nanoscale preparations, such as nanoparticles, micelles, and liposomes, are increasingly recognized in pharmaceutical technology for their high capability in tailoring the pharmacokinetics of the encapsulated drug within the body. These preparations have great potential in extending drug half-life, reducing dosing frequency, mitigating drug side effects, and enhancing drug efficacy. Consequently, nanoscale preparations offer promising prospects for the treatment of metabolic disorders, malignant tumors, and various chronic diseases. Nevertheless, the complete clinical potential of nanoscale preparations remains untapped due to the challenges associated with low drug loading degrees and insufficient control over drug release. In this review, we comprehensively summarize the vital role of intermolecular interactions in enhancing encapsulation and controlling drug release within nanoscale delivery systems. Our analysis critically evaluates the characteristics of common intermolecular interactions and elucidates the techniques employed to assess them. Moreover, we highlight the significant potential of intermolecular interactions in clinical translation, particularly in the screening and optimization of preparation prescriptions. By attaining a deeper understanding of intermolecular interaction properties and mechanisms, we can adopt a more rational approach to designing drug carriers, leading to substantial advancements in the application and clinical transformation of nanoscale preparations. Moving forward, continued research in this field offers exciting prospects for unlocking the full clinical potential of nanoscale preparations and revolutionizing the field of drug delivery.

Hydrazidomethyl starch as a pH-sensitive coating for magnetic core in tailored magnetic nanoparticles with selective doxorubicin release

The work aimed to use and modify starch as a biodegradable and biocompatible polysaccharide to create a modern pH-sensitive anticancer drug carrier based on a hydrazone bond. The multi-step reaction created a material that can bind to the carbonyl group of anticancer drugs. Additionally, polysaccharide was used to coat magnetic nanoparticles to increase the applicability of the carrier system. At each synthesis stage, the material was characterized in detail by performing FTIR-ATR spectra, thermal analysis, XRD, and SEM photos. In the next step, doxorubicin was loaded with a maximum of 19 % drug loading to the carrier via hydrazone bond. In the last research stage, the carrier-hydrazone bond-drug system was tested in solutions with different pH values, imitating the environments of a cancer cell, a healthy cell, and their subcellular elements regarding drug release from the carrier. The obtained release results indicate a >4-fold increase in the amount of drug released from the carrier in conditions of a slightly lower pH environment (70 %), compared to neutral pH (15 %). This represents a promising potential for using the material as an intelligent drug delivery system (DDS).

Aptamer-Based Smart Targeting and Spatial Trigger-Response Drug-Delivery Systems for Anticancer Therapy

In recent years, the field of drug delivery has witnessed remarkable progress, driven by the quest for more effective and precise therapeutic interventions. Among the myriad strategies employed, the integration of aptamers as targeting moieties and stimuli-responsive systems has emerged as a promising avenue, particularly in the context of anticancer therapy. This review explores cutting-edge advancements in targeted drug-delivery systems, focusing on the integration of aptamers and stimuli-responsive platforms for enhanced spatial anticancer therapy. In the aptamer-based drug-delivery systems, we delve into the versatile applications of aptamers, examining their conjugation with gold, silica, and carbon materials. The synergistic interplay between aptamers and these materials is discussed, emphasizing their potential in achieving precise and targeted drug delivery. Additionally, we explore stimuli-responsive drug-delivery systems with an emphasis on spatial anticancer therapy. Tumor microenvironment-responsive nanoparticles are elucidated, and their capacity to exploit the dynamic conditions within cancerous tissues for controlled drug release is detailed. External stimuli-responsive strategies, including ultrasound-mediated, photo-responsive, and magnetic-guided drug-delivery systems, are examined for their role in achieving synergistic anticancer effects. This review integrates diverse approaches in the quest for precision medicine, showcasing the potential of aptamers and stimuli-responsive systems to revolutionize drug-delivery strategies for enhanced anticancer therapy.

Natural Polymeric Nanobiocomposites for Anti-Cancer Drug Delivery Therapeutics: A Recent Update

Cancer is one of the most common lethal diseases and the leading cause of mortality worldwide. Effective cancer treatment is a global problem, and subsequent advancements in nanomedicine are useful as substitute management for anti-cancer agents. Nanotechnology, which is gaining popularity, enables fast-expanding delivery methods in science for curing diseases in a site-specific approach, utilizing natural bioactive substances because several studies have established that natural plant-based bioactive compounds can improve the effectiveness of chemotherapy. Bioactive, in combination with nanotechnology, is an exceptionally alluring and recent development in the fight against cancer. Along with their nutritional advantages, natural bioactive chemicals may be used as chemotherapeutic medications to manage cancer. Alginate, starch, xanthan gum, pectin, guar gum, hyaluronic acid, gelatin, albumin, collagen, cellulose, chitosan, and other biopolymers have been employed successfully in the delivery of medicinal products to particular sites. Due to their biodegradability, natural polymeric nanobiocomposites have garnered much interest in developing novel anti-cancer drug delivery methods. There are several techniques to create biopolymer-based nanoparticle systems. However, these systems must be created in an affordable and environmentally sustainable way to be more readily available, selective, and less hazardous to increase treatment effectiveness. Thus, an extensive comprehension of the various facets and recent developments in natural polymeric nanobiocomposites utilized to deliver anti-cancer drugs is imperative. The present article provides an overview of the latest research and developments in natural polymeric nanobiocomposites, particularly emphasizing their applications in the controlled and targeted delivery of anti-cancer drugs.

Acid/reduction dual-sensitive amphiphilic graft polyurethane with folic acid and detachable poly(ethylene glycol) as anticancer drug delivery carrier

In order to not only improve the stability of nanomicelles in blood circulation but also promote the cellular uptake in tumors and rapidly release the encapsulated drugs in tumor cells, a kind of acid/reduction dual-sensitive amphiphilic graft polyurethane with folic acid and detachable poly(ethylene glycol) (FA-PUSS-g_imi-mPEG) was synthesized by grafting folic acid and monomethoxy poly(ethylene glycol) to the polyurethane side chain. FA-PUSS-g_imi-mPEG could self-assemble in aqueous solution to form negatively charged nanomicelles, which endowed them good stability under normal physiological condition. Using ultraviolet-visible spectrometer (UV-vis) and dynamic light scattering (DLS), it was found that the hydrophilic poly(ethylene glycol) layer of FA-PUSS-g_imi-mPEG micelles could be detached due to the cleavage of benzoic-imine bond under slightly acidic condition, which resulted in reversing the charge of the micellar surface and exposing folic acid to the micellar surface. FA-PUSS-g_imi-mPEG micelles could load doxorubicin (DOX), moreover the drug release rate was faster at pH 5.0 and 10 mM glutathione (GSH) than that under normal physiological condition. The results of cell experiments further demonstrated that FA-PUSS-g_imi-mPEG micelles had acid/reduction dual-sensitive property. The changes in the structure of FA-PUSS-g_imi-mPEG micelles could enhance the cellular uptake under acid condition and the micelles could accelerate the drug release in tumor cells due to the presence of disulfide bonds in the polymer. Therefore, FA-PUSS-g_imi-mPEG micelles could efficiently deliver anticancer drug into tumor cells and enhance the inhibition of cellular proliferation through multi-effect synergy.

Construction of nano slow-release systems for antibacterial active substances and its applications: A comprehensive review

At present, nano-carrier materials with antibacterial activity are of great significance. Due to the widespread resistance of many pathogenic microorganisms, it has seriously threatened human health. The natural antimicrobial substances extracted from fruits and vegetables can significantly improve their stability combined with nano-carrier materials. The resistance of pathogenic microorganisms will be substantially reduced, greatly enhancing the effect of active antimicrobial substances. Nanotechnology has excellent research prospects in the food industry, antibacterial preservation, food additives, food packaging, and other fields. This paper introduces nano-carrier materials and preparation techniques for loading and encapsulating active antibacterial substances in detail by constructing a nano-release system for active antibacterial substances. The antibacterial effect can be achieved by protecting them from adverse external conditions and destroying the membrane of pathogenic microorganisms. The mechanism of the slow release of the bacteriostatic active substance is also described. The mechanism of carrier loading and release is mainly through non-covalent forces between the bacteriostatic active substance and the carrier material, such as hydrogen bonding, π-π stacking, van der Waals forces, electrostatic interactions, etc., as well as the loading and adsorption of the bacteriostatic active substance by the chemical assembly. Finally, its wide application in food and medicine is introduced. It is hoped to provide a theoretical basis and technical support for the efficient utilization and product development of bacteriostatic active substances.

Novel Tumor-Targeted Self-Nanostructured and Compartmentalized Water-in-Oil-in-Water Polyurethane-Polyurea Nanocapsules for Cancer Theragnosis

Encapsulation of water-soluble bioactive compounds for enabling specific accumulation in tumor locations, while avoiding premature clearance and/or degradation in the bloodstream, is one of the main hallmarks in nanomedicine, especially that of NIR fluorescent probes for cancer theragnosis. The herein reported technology furnishes water-dispersible double-walled polyurethane-polyurea hybrid nanocapsules (NCs) loaded with indocyanine green (ICG-NCs), using a versatile and highly efficient one-pot and industrially scalable synthetic process based on the use of two different prepolymers to set up the NCs walls. Flow cytometry and confocal microscopy confirmed that both ICG-loaded NCs internalized in monocyte-derived dendritic cells (moDCs). The in vivo analysis of xenograft A375 mouse melanoma model revealed that amphoteric functionalization of NCs' surface promotes the selective accumulation of ICG-NCs in tumor tissues, making them promising agents for a less-invasive theragnosis of cancer.

Nanoaggregates of Biphilic Carboxyl-Containing Copolymers as Carriers for Ionically Bound Doxorubicin

Application of nanocarriers for drug delivery brings numerous advantages, allowing both minimization of side effects common in systemic drug delivery and improvement in targeting, which has made it the focal point of nanoscience for a number of years. While most of the studies are focused on encapsulation of hydrophobic drugs, delivery of hydrophilic compounds is typically performed via covalent attachment, which often requires chemical modification of the drug and limits the release kinetics. In this paper, we report synthesis of biphilic copolymers of various compositions capable of self-assembly in water with the formation of nanoparticles and suitable for ionic binding of the common anticancer drug doxorubicin. The copolymers are synthesized by radical copolymerization of N-vinyl-2-pyrrolidone and acrylic acid using n-octadecyl-mercaptan as a chain transfer agent. With an increase of the carboxyl group's share in the chain, the role of the electrostatic stabilization factor of the nanoparticles increased as well as the ability of doxorubicin as an ion binder. A mathematical description of the kinetics of doxorubicin binding and release is given and thermodynamic functions for the equilibrium ionic binding of doxorubicin are calculated.

Biomedical Polyurethanes for Anti-Cancer Drug Delivery Systems: A Brief, Comprehensive Review

With the intensive development of polymeric biomaterials in recent years, research using drug delivery systems (DDSs) has become an essential strategy for cancer therapy. Various DDSs are expected to have more advantages in anti-neoplastic effects, including easy preparation, high pharmacology efficiency, low toxicity, tumor-targeting ability, and high drug-controlled release. Polyurethanes (PUs) are a very important kind of polymers widely used in medicine, pharmacy, and biomaterial engineering. Biodegradable and non-biodegradable PUs are a significant group of these biomaterials. PUs can be synthesized by adequately selecting building blocks (a polyol, a di- or multi-isocyanate, and a chain extender) with suitable physicochemical and biological properties for applications in anti-cancer DDSs technology. Currently, there are few comprehensive reports on a summary of polyurethane DDSs (PU-DDSs) applied for tumor therapy. This study reviewed state-of-the-art PUs designed for anti-cancer PU-DDSs. We studied successful applications and prospects for further development of effective methods for obtaining PUs as biomaterials for oncology.

Acid-sensitive charge-reversal co-assembled polyurethane nanomicelles as drug delivery carriers

In order to obtain drug delivery carriers with good stability in blood and high cellular uptake efficiency, carboxyl groups and tertiary amine groups were respectively introduced into polyurethane to synthesize two kinds of amphiphilic polyurethanes with opposite charges (PUC and PUN). Their structures were characterized by Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (¹H NMR) spectroscopy and gel permeation chromatography (GPC). PUC-PUN co-assembled nanomicelles were prepared by electrostatic interaction between PUC and PUN micelles, which showed acid-sensitive property. When the pH of the solution was decreased from 7.4 to 6.5, PUC-PUN-1 micelles showed negative-to-positive charge-reversal property among these micelles. The results of stability and cell experiments demonstrated that PUC-PUN-1 micelles not only had excellent stability in simulated normal physiological environment but also could obviously enhance the cellular uptake efficiency. PUC-PUN-1 micelles had low cytotoxicity against SGC-7901 and MGC-803 cells, whereas PUC-PUN-1/DOX micelles had higher cytotoxicity compared to pure DOX and PUN-1/DOX micelles. Moreover, the results of in vivo antitumor activity experiments showed that PUC-PUN-1/DOX micelles had better tumor inhibition ability and safety than pure DOX. In addition, the results of in vitro drug release experiments indicated that PUC-PUN-1/DOX micelles had almost no burst release or leakage of drugs in pH 7.4 environment. However, the drug release was accelerated in pH 5.0, which followed Fickian diffusion mechanism.

Dual responsive dextran-graft-poly (N-isopropylacrylamide)/doxorubicin prodrug via Schiff base reaction

Stimulus-responsive nanoparticles stand out in studies for cancer treatment since these systems can promote a selective release of the drug in tumor tissues and cells, minimizing the effects caused by conventional chemotherapy. Dextran-graft-poly (N-isopropylacrylamide) copolymers were synthesized via Schiff base formation. The synthesis of copolymers was confirmed by Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (NMR) and the analyses of dynamic light scattering (DLS) showed that the copolymers were thermal and pH dual-responsive. The chemotherapy drug doxorubicin (DOX) was conjugated to the copolymers via Schiff base formation, obtaining nanoparticles by self-assembling with size smaller than 130 nm. A higher percentage of doxorubicin was released at pH 5.0 (59.1 ± 2.1%) compared to physiological pH (34.9 ± 4.8%), confirming a pH-sensitive release profile. The in vitro cytotoxicity assay demonstrated that DOX-loaded nanoparticles can inhibit cancer cell proliferation and promote reduced cytotoxicity in non-tumor cells. The D_45kP_30k-DOX nanoparticles induced morphological changes in HCT-116 cells suggesting cell death and the cell uptake assay indicated that the nanoparticles can be internalized by endocytosis. Therefore, DOX-loaded nanoparticles exhibited potential as smart systems for cancer treatment.

Loading of doxorubicin on poly(methyl methacrylate-co-methacrylic acid) nanoparticles and release study

Nanoparticles (NP) of 12.7 nm in diameter of the poly(methyl methacrylate (MMA)-co-methacrylic acid (MAA)) copolymer were prepared. ¹³C-NMR results showed a MMA:MAA molar ratio of 0.64:0.36 in the copolymer, which is similar to the poly(MMA-co-MAA) commercially known as the FDA approved Eudragit S100 (0.67:0.33). The NP prepared in this study were loaded at pH 5 with varying amounts (from 0.54 to 6.91%) of doxorubicin (DOX), an antineoplastic drug. ¹H-NMR results indicated the electrostatic interactions between the ionized carboxylic groups of the MAA units in the copolymer and the proton of the glycosidic amine in DOX. Measurements by QLS and TEM indicated that the loading destabilizes the NP, and that for increase stability, they aggregate in a reversible way, forming aggregates with a diameter up to 99.5 nm at a DOX load of 6.91%. The analysis of drug release data at pH 7.4 showed that loaded NP with at least 4.38% DOX release the drug very slowly and follows the Higuchi model; the former suggests that they could remain for long periods in the bloodstream to reach and destroy cancer cells.

Doxorubicin-Loaded PLGA Nanoparticles for Cancer Therapy: Molecular Weight Effect of PLGA in Doxorubicin Release for Controlling Immunogenic Cell Death

Direct local delivery of immunogenic cell death (ICD) inducers to a tumor site is an attractive approach for leading ICD effectively, due to enabling the concentrated delivery of ICD inducers to the tumor site. Herein, we prepared doxorubicin (DOX)-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) using different molecular weight PLGA (7000 g/mol and 12,000 g/mol), showing different drug release kinetics. The different release kinetics of DOX might differently stimulate a tumor cell-specific immune response by releasing damage-associated molecular patterns (DAMPs), resulting in showing a different antitumor response in the living body. DOX-PLGA_7K NPs showed faster DOX release kinetics than DOX-PLGA_12K NPs in the physiological condition. DOX-PLGA_7K NPs and DOX-PLGA_12K NPs were successfully taken up by the CT-26 tumor cells, subsequently showing different DOX localization times at the nucleus. Released DOX successfully lead to cytotoxicity and HMGB1 release in vitro. Although the DOX-PLGA_7K NPs and DOX-PLGA_12K NPs showed different sustained DOX release kinetics in vitro, tumor growth of the CT-26 tumor was similarly inhibited for 28 days post-direct tumor injection. Furthermore, the immunological memory effect was successfully established by the ICD-based tumor-specific immune responses, including DC maturation and tumor infiltration of cytotoxic T lymphocytes (CTLs). We expect that the controlled release of ICD-inducible chemotherapeutic agents, using different types of nanomedicines, can provide potential in precision cancer immunotherapy by controlling the tumor-specific immune responses, thus improving the therapeutic efficacy.

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.