Formation of thermo-sensitive polyelectrolyte complex micelles from two biocompatible graft copolymers for drug delivery

Exploring the Application of Micellar Drug Delivery Systems in Cancer Nanomedicine

Various formulations of polymeric micelles, tiny spherical structures made of polymeric materials, are currently being investigated in preclinical and clinical settings for their potential as nanomedicines. They target specific tissues and prolong circulation in the body, making them promising cancer treatment options. This review focuses on the different types of polymeric materials available to synthesize micelles, as well as the different ways that micelles can be tailored to be responsive to different stimuli. The selection of stimuli-sensitive polymers used in micelle preparation is based on the specific conditions found in the tumor microenvironment. Additionally, clinical trends in using micelles to treat cancer are presented, including what happens to micelles after they are administered. Finally, various cancer drug delivery applications involving micelles are discussed along with their regulatory aspects and future outlooks. As part of this discussion, we will examine current research and development in this field. The challenges and barriers they may have to overcome before they can be widely adopted in clinics will also be discussed.

Advances of peptides for antibacterial applications

In the past few decades, peptide antibacterial products with unique antibacterial mechanisms have attracted widespread interest. They can effectively reduce the probability of drug resistance of bacteria and are biocompatible, so they possess tremendous development prospects. This review provides recent research and analysis on the basic types of antimicrobial peptides (including poly (amino acid)s, short AMPs, and lipopeptides) and factors to optimize antimicrobial effects. It also summarizes the two most important modes of action of antimicrobial peptides and the latest developments in the application of AMPs, including antimicrobial agent, wound healing, preservative, antibacterial coating and others. Finally, we discuss the remaining challenges to improve the antibacterial peptides and propose prospects in the field.

Polymeric micelles in cancer therapy: State of the art

In recent years, polymeric micelles have been extensively utilized in pre-clinical studies for delivering poorly soluble chemotherapeutic agents in cancer. Polymeric micelles are formed via self-assembly of amphiphilic polymers in facile manners. The wide availability of hydrophobic and, to some extent, hydrophilic polymeric blocks allow researchers to explore various polymeric combinations for optimum loading, stability, systemic circulation, and delivery to the target cancer tissues. Moreover, polymeric micelles could easily be tailor-made by increasing and decreasing the number of monomers in each polymeric chain. Some of the widely accepted hydrophobic polymers are poly(lactide) (PLA), poly(caprolactone) (PCL), poly(lactide-co-glycolide) (PLGA), polyesters, poly(amino acids), lipids. The hydrophilic polymers used to wrap the hydrophobic core are poly(ethylene glycol), poly(oxazolines), chitosan, dextran, and hyaluronic acids. Drugs could be conjugated to polymers at the distal ends to prepare pharmacologically active polymeric systems that impart enhanced solubility and stability of the conjugates and provide an opportunity for combination drug delivery. Their nano-size enables them to accumulate to the tumor microenvironment via the Enhanced Permeability and Retention (EPR) effect. Moreover, the stimuli-sensitive breakdown provides the micelles an effective means to deliver the therapeutic cargo effectively. The tumor micro-environmental stimuli are pH, hypoxia, and upregulated enzymes. Externally applied stimuli to destroy micellar disassembly to release the payload include light, ultrasound, and temperature. This article delineates the current trend in developing polymeric micelles combining various block polymeric scaffolds. The development of stimuli-sensitive micelles to achieve enhanced therapeutic activity are also discussed.

A review on recent advances in amino acid and peptide-based fluorescence and its potential applications

Fluorescence is widely used to detect functional groups and ions, and peptides are used in various fields due to their excellent biological activity.

A review of the properties and applications of bioadhesive hydrogels

Due to their outstanding properties, bioadhesive hydrogels have been extensively studied by researchers in recent years.

Temperature and H2O2-operated nano-valves on mesoporous silica nanoparticles for controlled drug release and kinetics

Temperature and H₂O₂ dual-responsive nanoparticles were fabricated from ferrocene modified mesoporous silica (MSN-Fc) and β-cyclodextrin-poly(N-isopropylacrylamide) (β-CD-PNIPAM) star-shaped polymer due to the host-guest interactions for controlled drug release. The formation and structure of β-CD-PNIPAM@MSN-Fc composite nanoparticles was confirmed by FTIR, TGA, TEM and N₂ adsorption-desorption isotherms. The size of nanoparticles was about 100-150 nm with well-ordered mesoporous structure and PNIPAM chains coating on the surface as outer shell. The channels of MSNs and hydrophobic cavities of β-CD were all contributed to the high drug loading capacity for nanoparticles. The release of DOX from nanoparticles was enhanced with the increase of temperature above LCST or adding H₂O₂ in ambient O₂. The release kinetics were studied using different models to explain drug release mechanism. Furthermore, the drug loaded composite nanoparticles exhibited excellent anti-cancer activity.

Multi-Responsive Nanocarriers Based on β-CD-PNIPAM Star Polymer Coated MSN-SS-Fc Composite Particles

A temperature, glutathione (GSH), and H₂O₂ multi-responsive composite nanocarrier (MSN-SS-Fc@β-CD-PNIPAM) based on β-cyclodextrin-poly(N-isopropylacrylamide) (β-CD-PNIPAM) star polymer capped ferrocene modified mesoporous silica nanoparticles (MSN-SS-Fc) was successfully prepared. The surface of the mesoporous silica was first modified by ferrocene (Fc) via a disulfide bond (-SS-) to form an oxidizing and reducing site and then complexed with a β-CD-PNIPAM star shaped polymer through host-guest interactions as a nano-valve to provide temperature responsive characteristics. The structure and properties of the complex nanoparticles were studied by FTIR, TGA, EDS, Zeta potential, and elemental analysis. Doxorubicin (DOX) and Naproxen (NAP), as model drugs, were loaded into nanocarriers to assess drug loading and release behaviour. The release of drugs from nanocarriers was enhanced with an increase of the GSH, H₂O₂ concentration, or temperatures of the solution. The kinetics of the release process were studied using different models. This nanocarrier presents successful multi-stimuli responsive drug delivery in optimal stimuli and provides potential applications for clinical treatment.

Construction and Swelling Properties of Thermosensitive N-isopropyl Acrylamide Microspheres With Controllable Size

In recent years, thermosensitive poly(N-isopropylacrylamide) (PNIPAM) microspheres have received extensive attention due to their many advantages, and their size and swelling ratio are two crucial factors. In this paper, homogeneous and hollow thermosensitive microspheres were prepared by free radical polymerization in an aqueous solution. The effects of the process parameters on the size of the microspheres were studied. The results indicated that the change in size during reaction at different temperatures was not obvious. The size of the microspheres ranged from 802 ± 35.4 nm to 423 ± 33.7 nm with the changes in the dosage of the initiator. Meanwhile, it was observed that the size of microspheres was slightly reduced due to the increase of reaction time. When the dosage of methyl methacrylate (MAA) is increased, the size of the hollow microspheres increased by more than 110%. The average size of the microspheres was smaller when the content of sodium dodecyl sulfate (SDS) was 3 wt%. The microspheres with varying reaction parameters showed a continuous decreasing swelling ratio when the temperatures were changed from 28 °C to 35 °C. In comparison with homogeneous microspheres, the average swelling ratio of hollow microspheres was larger.

In Situ Drug Delivery to Breast Cancer-Associated Extracellular Matrix

The extracellular matrix (ECM) contributes to tumor progression through changes induced by tumor and stromal cell signals that promote increased ECM density and stiffness. The increase in ECM stiffness is known to promote tumor cell invasion into surrounding tissues and metastasis. In addition, this scar-like ECM creates a protective barrier around the tumor that reduces the effectiveness of innate and synthetic antitumor agents. Herein, clinically approved breast cancer therapies as well as novel experimental approaches that target the ECM are discussed, including in situ hydrogel drug delivery systems, an emerging technology the delivers toxic chemotherapeutics, gene-silencing microRNAs, and tumor suppressing immune cells directly inside the tumor. Intratumor delivery of therapeutic agents has the potential to drastically reduce systemic side effects experienced by the patient and increase the efficacy of these agents. This review also describes the opposing effects of ECM degradation on tumor progression, where some studies report improved drug delivery and delayed cancer progression and others report enhanced metastasis and decreased patient survival. Given the recent increase in ECM-targeting drugs entering preclinical and clinical trials, understanding and addressing the factors that impact the effect of the ECM on tumor progression is imperative for the sake of patient safety and survival outcome.

Formation of complexes in aqueous solutions of amphiphilic triblock polyelectrolytes of different topologies and an oppositely charged protein

The complexation of lysozyme with aggregates from two triblock amphiphilic polyelectrolytes of the same blocks but different topologies and block molar masses, namely PS-b-SCPI-b-PEO and SCPI-b-PS-b-PEO, is investigated by scattering and spectroscopy methods. Light scattering reveals that the interaction with lysozyme causes shrinkage of the self-assembled nanoparticles in the case of the hydrophobic-polyelectrolyte-hydrophilic sequence. In the polyelectrolyte-hydrophobic-hydrophilic sequence, the opposite trend is observed. Small angle neutron scattering confirms the existence of micellar and fractal aggregates and the complexation with lysozyme. The pH-dependence of the interactions and the stability of the hybrid protein/polymer nanoparticles upon salt addition are tested. The native conformation of the protein is found to be preserved during complexation. This study reveals that both micellar and fractal aggregates made of amphiphilic triblock polyelectrolytes are capable of loading with oppositely charged proteins in a controllable manner, tuned primarily by the structure of the triblock terpolymer.

A biocompatible and magnetic nanocarrier with a safe UV-initiated docetaxel release and cancer secretion removal properties increases therapeutic potential for skin cancer

Cancer is a leading fatal disease worldwide. To increase its therapeutic efficiency, more effective with less side effect and patient acceptable administration approach is expected. Moreover, modification of tumor microenvironment is proved to be operative recently. In this paper, a nanocarrier named LDEDDS was developed for intelligent tropical administration of skin cancer, along with removal of hydrophobic cancerous secretion to change tumor microenvironment. It was made by coating of amphipathic polymer P(BA-co-HBA) on docetaxel (TXT, a model hydrophobic anticancer drug) loaded Fe₃O₄@ZnO. Results showed that an optimal loading rate of TXT in Fe₃O₄@ZnO was 89.75±0.15%, corresponding to loading capacity of 17.95±2.97% when the mass ratio of Fe₃O₄@ZnO to TXT was 1:20. The LDEDDS had a narrow distribution size of 115.8nm in average and was superparamagnetic. Without UV radiation, it had low TXT release (<7% in 48h) and cytotoxicity (<14% in 96h) to both the normal and carcinoma skin cells. While under a UV with a dose much lower than physiological dose of normal sunlight, LDEDDS released around 60% and 90% of TXT in 1 and 48h. 1h UV treated LDEDDS removed up to 62% of cancer secreted epidermal growth factor (EGF), a model hydrophobic secretion in 96h. Consequently, 1h UV treated LDEDDS inhibited up to 60% of the growth of skin cancer cells in 96h, overriding those effects of the same concentration of TXT in in vitro cellular experiments. This is the first study to change tumor microenvironment by removal of cancerous secretion and is proved to be effective. Along with the superparamagnetic property, which provides potential for concentrating, increasing penetration and internalization into cancerated cells as well as removing from body under an external magnetic field, we predict LDEDDS will have potential applications in clinic skin cancer therapy.

Temperature-Responsive Smart Nanocarriers for Delivery Of Therapeutic Agents: Applications and Recent Advances

Smart drug delivery systems (DDSs) have attracted the attention of many scientists, as carriers that can be stimulated by changes in environmental parameters such as temperature, pH, light, electromagnetic fields, mechanical forces, etc. These smart nanocarriers can release their cargo on demand when their target is reached and the stimulus is applied. Using the techniques of nanotechnology, these nanocarriers can be tailored to be target-specific, and exhibit delayed or controlled release of drugs. Temperature-responsive nanocarriers are one of most important groups of smart nanoparticles (NPs) that have been investigated during the past decades. Temperature can either act as an external stimulus when heat is applied from the outside, or can be internal when pathological lesions have a naturally elevated termperature. A low critical solution temperature (LCST) is a special feature of some polymeric materials, and most of the temperature-responsive nanocarriers have been designed based on this feature. In this review, we attempt to summarize recent efforts to prepare innovative temperature-responsive nanocarriers and discuss their novel applications.

PEG shielded MMP sensitive CPPs for efficient and tumor specific gene delivery in vivo

Gene therapy has great potential to treat a range of different diseases, such as cancer. For that therapeutic gene can be inserted into a plasmid vector and delivered specifically to tumor cells. The most frequently used applications utilize lipoplex and polyplex approaches where DNA is non-covalently condensed into nanoparticles. However, lack of in vivo efficacy is the major concern that hinders translation of such gene therapeutic applications into clinics. In this work we introduce a novel method for in vivo delivery of plasmid DNA (pDNA) and efficient tumor-specific gene induction using intravenous (i.v) administration route. To achieve this, we utilize a cell penetrating peptide (CPP), PepFect14 (PF14), double functionalized with polyethylene glycol (PEG) and a matrix metalloprotease (MMP) substrate. We show that this delivery vector effectively forms nanoparticles, where the condensed CPP and pDNA are shielded by the PEG, in an MMP-reversible manner. Administration of the complexes results in efficient induction of gene expression specifically in tumors, avoiding normal tissues. This strategy is a potent gene delivery platform that can be used for tumor-specific induction of a therapeutic gene.

Multifunctional polymeric micelles for delivery of drugs and siRNA

Polymeric micelles, self-assembling nano-constructs of amphiphilic copolymers with a core-shell structure have been used as versatile carriers for delivery of drugs as well as nucleic acids. They have gained immense popularity owing to a host of favorable properties including their capacity to effectively solubilize a variety of poorly soluble pharmaceutical agents, biocompatibility, longevity, high stability in vitro and in vivo and the ability to accumulate in pathological areas with compromised vasculature. Moreover, additional functions can be imparted to these micelles by engineering their surface with various ligands and cell-penetrating moieties to allow for specific targeting and intracellular accumulation, respectively, to load them with contrast agents to confer imaging capabilities, and incorporating stimuli-sensitive groups that allow drug release in response to small changes in the environment. Recently, there has been an increasing trend toward designing polymeric micelles which integrate a number of the above functions into a single carrier to give rise to “smart,” multifunctional polymeric micelles. Such multifunctional micelles can be envisaged as key to improving the efficacy of current treatments which have seen a steady increase not only in hydrophobic small molecules, but also in biologics including therapeutic genes, antibodies and small interfering RNA (siRNA). The purpose of this review is to highlight recent advances in the development of multifunctional polymeric micelles specifically for delivery of drugs and siRNA. In spite of the tremendous potential of siRNA, its translation into clinics has been a significant challenge because of physiological barriers to its effective delivery and the lack of safe, effective and clinically suitable vehicles. To that end, we also discuss the potential and suitability of multifunctional polymeric micelles, including lipid-based micelles, as promising vehicles for both siRNA and drugs.