Magnetic norbornene polymer as multiresponsive nanocarrier for site specific cancer therapy

Hydrophobic tag-based protein degradation: Development, opportunity and challenge

Targeted protein degradation (TPD) has emerged as a promising approach for drug development, particularly for undruggable targets. TPD technology has also been instrumental in overcoming drug resistance. While some TPD molecules utilizing proteolysis-targeting chimera (PROTACs) or molecular glue strategies have been approved or evaluated in clinical trials, hydrophobic tag-based protein degradation (HyT-PD) has also gained significant attention as a tool for medicinal chemists. The increasing number of reported HyT-PD molecules possessing high efficiency in degrading protein and good pharmacokinetic (PK) properties, has further fueled interest in this approach. This review aims to present the design rationale, hydrophobic tags in use, and diverse mechanisms of action of HyT-PD. Additionally, the advantages and disadvantages of HyT-PD in protein degradation are discussed. This review may help inspire the development of more HyT-PDs with superior drug-like properties for clinical evaluation.

Synthesis and characterization of poly(ethylene glycol) bottlebrush networks via ring‐opening metathesis polymerization

Herein it is reported how the overlap concentration (C*) can be used to overcome crosslinking due to diol impurities in commercial PEG, allowing for the synthesize of bottlebrush polymers with good control over molecular weight. Additionally, PEG-based bottlebrush networks are synthesized via ROMP, attaining high conversions with minimal sol fractions (<2%). The crystallinity and mechanical properties of these networks are then further altered by solvent swelling with phosphate buffer solution (PBS) and 1-ethyl-3-methylimidazolium ethyl sulfate/DCM cosolvents. The syntheses reported here highlight the potential of the bottlebrush network architecture for use in the rational design of new materials.

Applications of Fourier transform infrared spectroscopy to pharmaceutical preparations

Introduction: Various pharmaceutical preparations are widely used for clinical treatment. Elucidation of the mechanisms of drug release and evaluation of drug efficacy in biological samples are important in drug design and drug quality control.Areas covered: This review classifies recent applications of Fourier transform infrared (FTIR) spectroscopy in the field of medicine to comprehend drug release and diffusion. Drug release is affected by many factors of preparations, such as drug delivery system and microstructure polymorphism. The applications of FTIR imaging and nano-FTIR technique in biological samples lay a foundation for studying drug mechanism in vivo.Expert opinion: FTIR spectroscopy meets the research needs on preparations to understand the processes and mechanisms underlying drug release. The combination of attenuated total reflectance-FTIR imaging and nano-FTIR accompanied by chemometrics is a potent tool to overcome the deficiency of conventional infrared detection. FTIR shows an enormous potential in drug characterization, drug quality control, and bio-sample detection.

Pharmaceutical Applications of Iron-Oxide Magnetic Nanoparticles

Advances of nanotechnology led to the development of nanoparticulate systems with many advantages due to their unique physicochemical properties. The use of iron-oxide magnetic nanoparticles (IOMNPs) in pharmaceutical areas increased in the last few decades. This article reviews the conceptual information about iron oxides, magnetic nanoparticles, methods of IOMNP synthesis, properties useful for pharmaceutical applications, advantages and disadvantages, strategies for nanoparticle assemblies, and uses in the production of drug delivery, hyperthermia, theranostics, photodynamic therapy, and as an antimicrobial. The encapsulation, coating, or dispersion of IOMNPs with biocompatible material(s) can avoid the aggregation, biodegradation, and alterations from the original state and also enable entrapping the bioactive agent on the particle via adsorption or covalent attachment. IOMNPs show great potential for target drug delivery, improving the therapy as a consequence of a higher drug effect using lower concentrations, thus reducing side effects and toxicity. Different methodologies allow IOMNP synthesis, resulting in different structures, sizes, dispersions, and surface modifications. These advantages support their utilization in pharmaceutical applications, and getting suitable drug release control on the target tissues could be beneficial in several clinical situations, such as infections, inflammations, and cancer. However, more toxicological clinical investigations about IOMNPs are necessary.

Delivery of Doxorubicin Using Double-Layered Core-Shell Nanocarrier Based on Magnetic Fe3O4 Core and Salep Shells

Herein, we developed a magnetic drug delivery system based on magnetic Fe₃O₄ nanoparticles with double shells of modified salep polysaccharide for the delivery of doxorubicin (Dox). The drug-loaded nanocarrier was synthesized in an easy way, and large amounts of drug molecules were loaded into the nanocarrier. The drug-loaded nanocarrier showed excellent pH responsibility in vitro, and large amounts of Dox were released at lower pH (60% release), whereas the nanocarrier was stable at neutral pH. The hemolysis assay results showed that the nanocarrier has negligible hemolytic effects on human red blood cells and showed good biocompatibility. Moreover, the result of coagulation assays showed that the nanocarrier was not active in any coagulation pathways. Cytotoxicity assays of nanocarrier and drug-loaded nanocarrier toward HeLa cells demonstrated that the nanocarrier has negligible toxicity, whereas the drug-loaded nanocarrier kills more than 90% of cells during 48 h. The flow cytometry analysis also showed that the uptake of drug-loaded nanocarrier into the cancerous cells is time-dependent and higher concentrations of drug internalized into the cells at longer incubation time. On the basis of the results, we suggest that the present nanocarrier can be applicable for in vivo drug delivery as an easy-made and cheap nanocarrier.

A carboxymethyl dextran-based polymeric conjugate as the antigen carrier for cancer immunotherapy

BACKGROUND

Antigen-specific cytotoxic T lymphocytes (CTLs), which eliminate target cells bearing antigenic peptides presented by surface major histocompatibility complex (MHC) class I molecules, play a key role in cancer immunotherapy. However, the majority of tumors are not immunologically rejected since they express self-antigens which are not recognized by CTLs as foreign. To foreignize these tumors for CTL-mediated immunological rejection, it is essential to develop carriers that can effectively deliver foreign antigens to cancer cells.

METHODS

A polymeric conjugate, composed of a carboxymethyl dextran (CMD) as the backbone and ovalbumin (OVA) as a model foreign antigen, was prepared to investigate its potential as the antigen carrier for cancer immunotherapy.

RESULTS

An in vitro cellular uptake study showed that the conjugate was successfully taken up by TC-1 cervical cancer cells. When CMD-OVA was systemically administered to tumor-bearing mice, the strong fluorescence signal was observed at the tumor site over the whole period of time period, suggesting high tumor targetability of the conjugate. Compared to free OVA, CMD-OVA induced significantly higher antigen presentation at the tumor site.

CONCLUSIONS

The CMD-OVA conjugate can effectively deliver the antigen to the tumor site, implying its high potential as the antigen carrier for cancer immunotherapy.

Recent Progress and Advances in Stimuli-Responsive Polymers for Cancer Therapy

The conventional chemotherapeutic agents, used for cancer chemotherapy, have major limitations including non-specificity, ubiquitous biodistribution, low concentration in tumor tissue, and systemic toxicity. In recent years, owing to their unique features, polymeric nanoparticles have been widely used for the target-specific delivery of drugs in the body. Although polymeric nanoparticles have addressed a number of important issues, the bioavailability of drugs at the disease site, and especially upon cellular internalization, remains a challenge. A polymer nanocarrier system with a stimuli-responsive property (e.g., pH, temperature, or redox potential), for example, would be amenable to address the intracellular delivery barriers by taking advantage of pH, temperature, or redox potentials. With a greater understanding of the difference between normal and pathological tissues, there is a highly promising role of stimuli-responsive nanocarriers for drug delivery in the future. In this review, we highlighted the recent advances in different types of stimuli-responsive polymers for drug delivery.

Anti-Trop2 antibody-conjugated bioreducible nanoparticles for targeted triple negative breast cancer therapy

Trop2, a transmembrane glycoprotein, has emerged as a biomarker for targeted cancer therapy since it is overexpressed in 80% of triple negative breast cancer (TNBC) patients. For the site-specific delivery of the anticancer drug into TNBC, anti-Trop2 antibody-conjugated nanoparticles (ST-NPs) were prepared as the potential nanocarrier, composed of carboxymethyl dextran (CMD) derivatives with bioreducible disulfide bonds. Owing to its amphiphilicity, the CMD derivatives were self-assembled into nano-sized particles in an aqueous condition. Doxorubicin (DOX), chosen as a model anticancer drug, was effectively encapsulated into the nanoparticles. DOX-loaded ST-NPs (DOX-ST-NPs) rapidly released DOX in the presence of 10mM glutathione (GSH), whereas the DOX release is significantly retarded in the physiological condition (PBS, pH 7.4). Confocal microscopic images and flow cytometry analysis demonstrated that DOX-ST-NPs were selectively taken up by MDA-MB-231 as the representative Trop2-expressing TNBC cells. Consequently, DOX-ST-NPs exhibited higher toxicity to Trop2-positive MDA-MB-231 cancer cells, compared to DOX-loaded control nanoparticles without the disulfide bond or anti-Trop2 antibody. Overall, ST-NPs might be a promising carrier of DOX for targeted TNBC therapy.

Synthesis, Characterization and Thermal Properties of Poly(ethylene oxide), PEO, Polymacromonomers via Anionic and Ring Opening Metathesis Polymerization

Branched polymers are a valuable class of polymeric materials. In the present study, anionic polymerization techniques were employed for the synthesis of low molecular weight poly(ethylene oxide) (PEO) macromonomers bearing norbornenyl end groups. The macromonomers were characterized by SEC, MALDI-TOF and NMR spectroscopy. Subsequent ring opening metathesis polymerization (ROMP) of the macromonomers using ruthenium catalysts (Grubbs catalysts of the 1st, 2nd and 3rd generations) afforded the corresponding polymacromonomers. The effects of the macromonomer molecular weight, the type of the catalyst, the nature of the solvent, the monomer concentration and the polymerization temperature on the molecular characteristics of the branched polymers were examined in detail. The crystallization behavior of the macromonomers and the corresponding polymacromonomers were studied by Differential Scanning Calorimetry (DSC). The thermal stability and the kinetics of the thermal decomposition of the samples were also studied by Thermogravimetric Analysis (TGA). The activation energies of the thermal decomposition were analyzed using the Ozawa–Flynn–Wall and Kissinger methodologies.

Dynamic Nanoparticle Assemblies for Biomedical Applications

Designed synthesis and assembly of nanoparticles assisted by their surface ligands can create "smart" materials with programmed responses to external stimuli for biomedical applications. These assemblies can be designed to respond either exogenously (for example, to magnetic field, temperature, ultrasound, light, or electric pulses) or endogenously (to pH, enzymatic activity, or redox gradients) and play an increasingly important role in a diverse range of biomedical applications, such as biosensors, drug delivery, molecular imaging, and novel theranostic systems. In this review, the recent advances and challenges in the development of stimuli-responsive nanoparticle assemblies are summarized; in particular, the application-driven design of surface ligands for stimuli-responsive nanoparticle assemblies that are capable of sensing small changes in the disease microenvironment, which induce the related changes in their physico-chemical properties, is described. Finally, possible future research directions and problems that have to be addressed are briefly discussed.

pH-Sensitive Nanoaggregates for Site-Specific Drug-Delivery as Well as Cancer Cell Imaging

Multifunctional polymeric nanoaggregates could enable targeted cancer therapy and imaging, which eventually facilitate monitoring of the therapeutic effect. A fluorescent nanoaggregate is constructed for theranostic application. Chlorambucil (Chl), a fluorescent inactive chemotherapeutic agent, is covalently attached to the nanoaggregate for therapeutic action. The pyrene (Py) motif is also covalently attached to the nanoaggregates, with the motivation of cancer cell imaging. This nanoaggregate is further functionalized with biotin (Btn) for receptor-mediated drug delivery. The efficiency of this system is evaluated by in vitro cell studies to prove its receptor-mediated internalization as well as theranostic capabilities. This newly designed nanocarrier, Nor-Chl-Py-Btn (Nor, norbornene), has the ability to combine both therapeutic and diagnostic capabilities into a single polymer that offers existing prospects for the development of nanomedicine.

Modular Design of Poly(norbornenes) for Organelle-Specific Imaging in Tumor Cells

Through modular ROMP (ring-opening metathesis polymerization) directly from monomeric norbornenes of bioactive peptides, rhodamine B chromophore, and PEG solubilizer, we designed and synthesized a series of water-soluble poly(norbornenes) with organelle-specific imaging capability in tumor cells. For the selection of FxrFxK, TAT, and SV40 peptide sequences, these fluorescence probes exhibited different targeting specificity toward mitochondria, lysosome, and nucleolus, respectively, based on the same poly(norbornene) backbonds. More importantly, the ROMP strategy enables selective combination from various monomers and allows programmable biofunctionalization via peptide sequence permutations, which would greatly extend the biomedical applications such as imaging, diagnosis, and therapy for these synthetic polymers.

Unique nanotubes from polynorbornene derived graphene sheets

Graphene functionalized polynorbornene nanohybrids (PNAGRs) have been synthesized successfully and their interesting self-aggregation in organic solvent (tetrahydrofuran, THF) has been investigated thoroughly for the 1^st time in our present study.

Switchable two-photon imaging of RGD-functionalized polynorbornenes with enhanced cellular uptake in living cells

Two-photon imaging polynorbornenes were fabricated directly from photochromic spiropyran, RGD peptides and hydrophilic PEG monomers via modular ROMP.

Recent developments in hyaluronic acid-based nanomedicine for targeted cancer treatment

INTRODUCTION

Hyaluronic acid (HA) has emerged as a promising applicant for the tumor-targeted delivery of various therapeutic agents. Because of its biocompatibility, biodegradability and receptor-binding properties, HA has been extensively investigated as the drug delivery carrier. In this review, recent advances in HA-based nanomedicines are discussed.

AREAS COVERED

This review focuses on HA-based nanomedicines for the diagnosis and treatment of cancer. In particular, recent advances in HA-drug conjugates and HA-based nanoparticles for small molecular drug delivery are discussed. The bioreducible HA conjugates for small interfering ribonucleic acid delivery have been also discussed.

EXPERT OPINION

To develop a successful HA-based nanomedicine, it has to be prepared without significant deterioration of intrinsic property of HA. The chemical modification of HA with drugs or hydrophobic moieties may reduce the binding affinity of HA to the receptors. In addition, since the HA-based nanomedicines tend to accumulate in the liver after their systemic administration, new strategies to overcome this issue have to be developed.

A renewable resource-derived thixotropic self-assembled supramolecular gel: magnetic stimuli responsive and real-time self-healing behaviour

A simple fluorescent, self-healing and magnetic responsive molecular gel was developed from a renewable resource.

A versatile gold cross-linked nanoparticle based on triblock copolymer as the carrier of doxorubicin

Gold cross-linked nanoparticles based on PCL-b-PDMAEMA-b-PEG triblock copolymer has been developed as a carrier for anticancer drugs with enhanced biostability.

Targeting delivery and deep penetration using multistage nanoparticles for triple-negative breast cancer

Targeting delivery and size-induced deep penetration have been applied in triple-negative breast cancer (TNBC) theranostics.

Promises and pitfalls of intracellular delivery of proteins

The direct delivery of functional proteins into the cell cytosol is a key issue for protein therapy, with many current strategies resulting in endosomal entrapment. Protein delivery to the cytosol is challenging due to the high molecular weight and the polarity of therapeutic proteins. Here we review strategies for the delivery of proteins into cells, including cell-penetrating peptides, virus-like particles, supercharged proteins, nanocarriers, polymers, and nanoparticle-stabilized nanocapsules. The advantages and disadvantages of these approaches including cytosolar delivery are compared and contrasted, with promising pathways forward identified.

Efficient approach to prepare multiple chemotherapeutic agent conjugated nanocarrier

A pH-responsive, multiple chemotherapeutic agent derived nanocarrier has been synthesized by conjugating doxorubicin, indomethacin, and folate to the backbone of norbornene polymer.