Synthesis and self-assembly of amphiphilic poly(acrylic acid-b-dl-lactide) to form micelles for pH-responsive drug delivery

Cu (II)-porphyrin metal-organic framework/graphene oxide: synthesis, characterization, and application as a pH-responsive drug carrier for breast cancer treatment

A new multifunctional graphene oxide/Cu (II)-porphyrin MOF nanocomposite (CuG) comprised of Cu-TCPP MOF supported on graphene oxide (GO) nanosheets, has been fabricated by a solvothermal method at low temperature and one-pot process. Cu-TCPP MOF with universal advantages, such as high porosity, nontoxicity, large surface area, and safe biodegradation, combined with GO allows the achievement of an efficient doxorubicin loading (45.7%) and smart pH-responsive release for chemotherapy. More significantly, more than 97% of DOX was released by CuG at pH 5 which was more than that at pH 7.4 (~ 33.5%), while Cu-TCPP MOF displayed DOX release of 68.5% and 49% at pH 5 and 7.4, respectively, illustrating the effect of GO on the smart MOF construction for controllable releasing behavior in vitro. The results of in vitro anticancer experiments demonstrate that the developed nanocarrier exhibited slight or no cytotoxicity on normal cells, while the drug-loaded nanocarrier increased significant cancer cell-killing ability with higher therapeutic efficacy than free DOX, indicating the sustained release behavior of the CuG nanocarrier without any "burst effect". Moreover, the in vivo experiments demonstrated that the CuG-DOX exhibited significantly higher anticancer efficiency compared with free DOX. High anti-cancer therapeutic efficacy of this nanoscale carrier as an efficient pH sensitive agent, has the potential to enter further biomedical investigations. A new smart multifunctional graphene oxide-Cu (II)-porphyrin MOF nanocomposite (CuG) formed of Cu-TCPP MOF and graphene oxide (GO) has successfully fabricated and demonstrated an efficient pH-responsive drug release behavior in cancer therapy without using any targeting ligand.

Theranostic potential of biodegradable polymeric nanoparticles with paclitaxel and curcumin against breast carcinoma

In this study, integrin-mediated targeting and near-infrared fluorescence (NIRF) traceable polyethylene glycol-b-poly(lactic-co-glycolic acid) (PEG-PLGA)-based polymeric nanoparticles (NPs) were prepared to investigate the effects of paclitaxel (PTX) and curcumin (CUR) combination therapy on breast cancer. Cyclic (arginine-glycine-aspartic acid-phenylalanine-lysine) (cRGDfK) was selected as a ligand for breast cancer and conjugated to the end of NPs (cRGDfK-NPs). For fluorescence imaging, sulfo-cyanine 5.5 (Cy5.5) was incorporated into NPs (Cy5.5-NPs). A series of hybrid NPs consisting of NPs, cRGDfK-NPs, and Cy5.5-NPs with drugs encapsulated inside the core (Cy5.5-cRGDfK-NPs/PTX + CUR) were prepared by self-assembly. The efficacy of PTX and CUR combination and the ability of the integrin-mediated targeting of NPs were systemically investigated using a 4T1 mouse breast cancer cell line and a nude mouse xenograft model. We suggested that Cy5.5-cRGDfK-NPs/PTX + CUR has superior theranostic potential against breast carcinoma.

A small molecule nanodrug consisting of pH-sensitive ortho ester-dasatinib conjugate for cancer therapy

The main objective of this paper is to develop a self-delivered prodrug system with nanoscale characteristics to enhance the efficacy of tumor therapy. The pH-sensitive prodrug was composed of ortho ester-linked dasatinib (DAS-OE), which was further self-assembled with or without doxorubicin (DOX) to obtain two carrier-free nanoparticles (DOX/DAS-OE NPs or DAS-OE NPs). The prodrug-based nanoparticles united the superiorities of small molecules and nano-assemblies together and displayed well-defined structure, uniform spherical shape, high drug loading ratio and on-demand drug release behavior. The drug loading content of DAS and DOX was 61.6% and 21.9%, respectively, and more than 80.2% of DAS and 60.2% DOX were released from DOX/DAS-OE NPs within 20 h at pH 5.0. Both in vitro and in vivo studies demonstrated that the pH-sensitive ortho ester bonds in the prodrug underwent hydrolysis to release DAS and DOX simultaneously after cellular internalization, resulting in remarkable antitumor effect. Tumor growth inhibition rate was 19.9% (free DAS), 35.5% (free DOX), 66.3% (DAS-OE NPs) and 82.8% (DOX/DAS-OE NPs), respectively. Thus, the ortho ester-linked prodrug system shows great potentials in cancer therapy.

Silica-Based Nanoparticles as Drug Delivery Vehicles for Prostate Cancer Treatment

Prostate cancer (PCa) is one of the most commonly diagnosed cancers and is the fifth common cause of cancer-related mortality in men. Current methods for PCa treatment are insufficient owing to the challenges related to the non-specificity, instability and side effects caused by the drugs and therapy agents. These drawbacks can be mitigated by the design of a suitable drug delivery system that can ensure targeted delivery and minimise side effects. Silica based nanoparticles (SBNPs) have emerged as one of the most versatile materials for drug delivery due to their tunable porosities, high surface area and tremendous capacity to load various sizes and chemistry of drugs. This review gives a brief overview of the diagnosis and current treatment strategies for PCa outlining their existing challenges. It critically analyzes the design, development and application of pure, modified and hybrid SBNPs based drug delivery systems in the treatment of PCa, their advantages and limitations.

Novel pH-Sensitive Urushiol-Loaded Polymeric Micelles for Enhanced Anticancer Activity

Purpose

The aim of this study was to develop a means of improving the bioavailability and anticancer activity of urushiol by developing an urushiol-loaded novel tumor-targeted micelle delivery system based on amphiphilic block copolymer poly(ethylene glycol)-b-poly-(β-amino ester) (mPEG-PBAE).

Materials and Methods

We synthesized four different mPEG-PBAE copolymers using mPEG-NH₂ with different molecular weights or hydrophobicity levels. Of these, we selected the mPEG₅₀₀₀-PBAE-C₁₂ polymer and used it to develop an optimized means of preparing urushiol-loaded micelles. Response surface methodology was used to optimize this formulation process. The micellar properties, including particle size, pH sensitivity, drug release dynamics, and critical micelle concentrations, were characterized. We further used the MCF-7 human breast cancer cell line to explore the cytotoxicity of these micelles in vitro and assessed their pharmacokinetics, tissue distribution, and antitumor activity in vivo.

Results

The resulting micelles had a mean particle size of 160.1 nm, a DL value of 23.45%, and an EE value of 80.68%. These micelles were found to release their contents in a pH-sensitive manner in vitro, with drug release being significantly accelerated at pH 5.0 (98.74% in 72 h) without any associated burst release. We found that urushiol-loaded micelles were significantly better at inducing MCF-7 cell cytotoxicity compared with free urushiol, with an IC₅₀ of 1.21 mg/L. When these micelles were administered to tumor model animals in vivo, pharmacokinetic analysis revealed that the total AUC and MRT of these micelles were 2.28- and 2.53-fold higher than that of free urushiol, respectively. Tissue distribution analyses further revealed these micelles to mediate significantly enhanced tumor urushiol accumulation.

Conclusion

The pH-responsive urushiol-loaded micelles described in this study may be ideally suited for clinical use for the treatment of breast cancer.

The Influence of Mucin-Based Artificial Saliva on Properties of Polycaprolactone and Polylactide

Polycaprolactone (PCL) and polylactide (PLA) are the two most common biodegradable polymers with potential use in oral applications. Both polymers undergo mainly slow hydrolytic degradation in the human body. However, specific conditions of the oral cavity, like elevated temperature, low pH, and presence of saliva affect the rate of hydrolysis. The study examined the properties of solid samples of PCL and PLA subjected to degradation in phosphate buffered saline (PBS) and artificial saliva (AS) at temperatures of 37 or 42 °C, and pH values 2 or 7.4. A number of tests were performed, including measurement of the degree of swelling, weight loss, molecular weight, differential scanning calorimetry, and thermogravimetry of polymers, as well as hardness and tensile strength. Additionally, topography and stiffness of surfaces using atomic force microscopy are presented. It has been noticed that in the artificial saliva, the processes of polymer degradation occur slightly more slowly, and the effects of temperature and pH are less pronounced. We believe that a layer of porcine gastric mucin from artificial saliva that adsorbed on the surface of polymers may have a key role in the observed differences; this layer resembles protective mucin coating tissues in the oral cavity.

Emerging Applications of Porphyrins and Metalloporphyrins in Biomedicine and Diagnostic Magnetic Resonance Imaging

In recent years, scientific advancements have constantly increased at a significant rate in the field of biomedical science. Keeping this in view, the application of porphyrins and metalloporphyrins in the field of biomedical science is gaining substantial importance. Porphyrins are the most widely studied tetrapyrrole-based compounds because of their important roles in vital biological processes. The cavity of porphyrins containing four pyrrolic nitrogens is well suited for the binding majority of metal ions to form metalloporphyrins. Porphyrins and metalloporphyrins possess peculiar photochemical, photophysical, and photoredox properties which are tunable through structural modifications. Their beneficial photophysical properties, such as the long wavelength of emission and absorption, high singlet oxygen quantum yield, and low in vivo toxicity, have drawn scientists' interest to discover new dimensions in the biomedical field. Applications of porphyrins and metalloporphyrins have been pursued in the perspective of contrast agents for magnetic resonance imaging (MRI), photodynamic therapy (PDT) of cancer, bio-imaging, and other biomedical applications. This review discusses photophysics and the photochemistry of porphyrins and their metal complexes. Secondly, it explains the current developments and mode of action for contrast agents for MRI. Moreover, the application of porphyrin and metalloporphyrin-based molecules as a photosensitizer in PDT of cancer, the mechanism of the generation of reactive oxygen species (ROS), factors that determine the efficiency of PDT, and the developments to improve this technology are delineated. The last part explores the most recent research and developments on metalloporphyrin-based materials in bio-imaging, drug delivery, and the determination of ferrochelatase in bone marrow indicating their prospective clinical applications.

Glutathione-dependent micelles based on carboxymethyl chitosan for delivery of doxorubicin

Novel glutathione (GSH)-dependent micelles based on carboxymethyl chitosan (CMCS) were developed for triggered intracellular release of doxorubicin (DOX). DOX-33'-Dithiobis (N-hydroxysuccinimidyl propionate)-CMCS (DOX-DSP-CMCS) prodrugs were synthesized. DOX was attached to the amino group on CMCS via disulfide bonds and drug-loaded micelles were formed by self-assembly. The micelles formed core-shell structure with CMCS and DOX as the shell and core, respectively, in aqueous media. The structure of the prodrugs was confirmed by IR and proton nuclear magnetic resonance (¹H NMR) spectroscopy. The drug-loading capacity determined by UV spectrophotometry was 4.96% and the critical micelle concentration of polymer prodrugs determined by pyrene fluorescence was 0.089 mg/mL. Micelles were spherical and the mean size of the nanoparticles was 174 nm, with a narrow polydispersity index of 0.106. Moreover, in vitro drug release experiments showed that the micelles were highly GSH-sensitive owing to the reductively degradable disulfide bonds. Cell counting kit (CCK-8) assays revealed that DOX-DSP-CMCS micelles exhibited effective cytotoxicity against HeLa cells. Moreover, confocal laser scanning microscopy (CLSM) demonstrated that DOX-DSP-CMCS micelles could efficiently deliver and release DOX in the cancer cells. In conclusion, the DOX-DSP-CMCS nanosystem is a promising drug delivery vehicle for cancer therapy.

Supramolecular prodrug micelles based on the complementary multiple hydrogen bonds as drug delivery platform for thrombosis therapy

To improve the effect of thrombosis therapy, an amphiphilic supramolecular prodrug consisting of diosgenin derivative (theophylline–diosgenin) and uracil-terminated poly(ethylene glycol) (PEG-U) was designed and synthesized successfully.

Preparation and characterization of amphiphilic calixarene nanoparticles as delivery carriers for paclitaxel

Two types of amphoteric calix[n]arene carboxylic acid (CnCA) derivative, i.e., calix[6]arene hexa-carboxylic acid (C6HCA) and calix[8]arene octo-carboxylic acid (C8OCA), were synthesized by introducing acetoxyls into the hydroxyls of calix[n]arene (n=6, 8). C6HCA and C8OCA nanoparticles (NPs) were prepared successfully using the dialysis method. CnCA NPs had regular spherical shapes with an average diameter of 180-220 nm and possessed negative charges of greater than -30 mV. C6HCA and C8OCA NPs were stable in 4.5% bovine serum albumin solutions and buffers (pH 5-9), with a low critical aggregation concentration value of 5.7 mg·L(-1) and 4.0 mg·L(-1), respectively. C6HCA and C8OCA NPs exhibited good paclitaxel (PTX) loading capacity, with drug loading contents of 7.5% and 8.3%, respectively. The overall in vitro release behavior of PTX from the CnCA NPs was sustained, and C8OCA NPs had a slower release rate compared with C6HCA NPs. These favorable properties of CnCA NPs make them promising nanocarriers for tumor-targeted drug delivery.

An interpenetrated bioactive nonlinear optical MOF containing a coordinated quinolone-like drug and Zn(ii) for pH-responsive release

An interpenetrated acentric bioactive MOF with a high drug content of 63.9% has been prepared, which shows a good release of the drug and a strong SHG signal.

Nanoparticle assembly of a photo- and pH-responsive random azobenzene copolymer

Stimuli-responsive polymeric nanoparticles with a core of hydrophobic azobenzene-containing acrylate units and a shell of hydrophilic acrylic acid units were prepared from a novel photo- and pH-responsive amphiphilic random azobenzene copolymer. Upon UV light irradiation, the trans azobenzene changed to the cis form and thus the water contact angle and the absorption of water on the polymer film could be changed, while little effect was exerted on the morphology of the nanoparticles although the polarity of the core of nanoparticles increased. Adjusting pH of the nanoparticle solution could exert a strong effect on the morphology of the nanoparticles. The prime nanoparticles (pH 6) changed to nanoparticle aggregates at pH 3, and to swollen nanoparticles at pH 11. The controlled release of Nile Red from the nanoparticles under the stimuli was demonstrated.

Poly(ethylene glycol)-poly(lactic-co-glycolic acid) based thermosensitive injectable hydrogels for biomedical applications

Stimuli triggered polymers provide a variety of applications related with the biomedical fields. Among various stimuli triggered mechanisms, thermoresponsive mechanisms have been extensively investigated, as they are relatively more convenient and effective stimuli for biomedical applications. In a contemporary approach for achieving the sustained action of proteins, peptides and bioactives, injectable depots and implants have always remained the thrust areas of research. In the same series, Poloxamer based thermogelling copolymers have their own limitations regarding biodegradability. Thus, there is a need to have an alternative biomaterial for the formulation of injectable hydrogel, which must remain biocompatible along with safety and efficacy. In the same context, poly(ethylene glycol) (PEG) based copolymers play a crucial role as a biomedical material for biomedical applications, because of their biocompatibility, biodegradability, thermosensitivity and easy controlled characters. This review stresses on the physicochemical property, stability and composition prospects of smart PEG/poly(lactic-co-glycolic acid) (PLGA) based thermoresponsive injectable hydrogels, recently utilized for biomedical applications. The manuscript also highlights the synthesis scheme and stability characteristics of these copolymers, which will surely help the researchers working in the same area. We have also emphasized the applied use of these smart copolymers along with their formulation problems, which could help in understanding the possible modifications related with these, to overcome their inherent associated limitations.

Bioavailability of phytochemicals and its enhancement by drug delivery systems

Issues of poor oral bioavailability of cancer chemopreventives have hindered progress in cancer prevention. Novel delivery systems that modulate the pharmacokinetics of existing drugs, such as nanoparticles, cyclodextrins, niosomes, liposomes and implants, could be used to enhance the delivery of chemopreventive agents to target sites. The development of new approaches in prevention and treatment of cancer could encompass new delivery systems for approved and newly investigated compounds. In this review, we discuss some of the delivery approaches that have already made an impact by either delivering a drug to target tissue or increasing its bioavailability by many fold.

Stimulus-sensitive polymeric nanoparticles and their applications as drug and gene carriers

Polymeric nanoparticles are promising candidates as drug and gene carriers. Among polymeric nanoparticles, those that are responsive to internal or external stimuli are of greater interest because they allow more efficient delivery of therapeutics to pathological regions. Stimulus-sensitive polymeric nanoparticles have been fabricated based on numerous nanostructures, including micelles, vesicles, crosslinked nanoparticles, and hybrid nanoparticles. The changes in chemical or physical properties of polymeric nanoparticles that occur in response to single, dual, or multiple stimuli endow these nanoparticles with the ability to retain cargoes during circulation, target the pathological region, and release their cargoes after cell internalization. This Review focuses on the most recent developments in the preparation of stimulus-sensitive polymeric nanoparticles and their applications in drug and gene delivery.