iRGD mediated pH-responsive mesoporous silica enhances drug accumulation in tumors

The limited penetration of nanocarriers into tumors and the slow release of drugs from these carriers to tumor cells are significant challenges in cancer therapy. In this study, we developed a novel drug delivery carrier derived from mesoporous silica, dually modified with the tumor-homing cyclic peptide iRGD (CRGDKGPDC) and the pH-responsive polymer poly(2-ethyl-2-oxazoline) (PEOz) for treating triple-negative breast cancer. The carrier selectively bound to the αvβ3 integrin receptor, which is specifically expressed in MDA-MB-231 breast cancer cells and vessels. Subsequently, it penetrated deep into the tumor parenchyma through NRP-1 receptor-dependent internalization, with the drug-loaded particles releasing drugs rapidly in the acidic cytoplasmic environment. Results indicated that the drug release rate of PEOz-modified formulations was pH-dependent. Lysosomal escape experiments demonstrated that PEOz-modified particles efficiently escaped lysosomes to release drugs. In vitro cytotoxicity assays revealed that iRGD-functionalized particles were more cytotoxic to NRP-1-positive MDA-MB-231 cells compared to NRP-1-negative MCF-7 cells. Cellular uptake studies demonstrated that iRGD mediated enhanced endocytosis of nanoparticles into MDA-MB-231 cells. In vitro tumor cell spheroid penetration assays confirmed that the PEOz and iRGD dual-modified carrier facilitated deeper distribution of DOX in multicellular spheroids compared to free DOX. Moreover, in a nude mouse model of triple-negative breast cancer, the dual-modified drug-loaded carrier significantly inhibited tumor growth without inducing weight loss or liver and kidney damage. This dual-modified mesoporous silica presents a novel and promising delivery carrier for enhancing cancer treatment.

Layer-by-layer development of chitosan/alginate-based platelet-mimicking nanocapsules for augmenting doxorubicin cytotoxicity against breast cancer

Breast carcinoma is considered one of the most invasive and life-threatening malignancies in females. Mastectomy, radiation therapy, hormone therapy and chemotherapy are the most common treatment choices for breast cancer. Doxorubicin (DOX) is one of the most regularly utilized medications in breast cancer protocols. However, DOX has showed numerous side effects including lethal cardiotoxicity. This study aims to fortify DOX cytotoxicity and lowering its side effects via its combining with the antidiabetic metformin (MET) as an adjuvant therapy, along with its effective delivery using natural platelet-rich plasma (PRP), and newly-developed PRP-mimicking nanocapsules (NCs). The PRP-mimicking NCs were fabricated via layer-by-layer (LBL) deposition of oppositely charged biodegradable and biocompatible chitosan (CS) and alginate (ALG) on a core of synthesized polystyrene nanoparticles (PS NPs) followed by removal of the PS core. Both natural PRP and PRP-mimicking NCs were loaded with DOX and MET adjuvant therapy, followed by their physicochemical characterizations including DLS, FTIR, DSC, and morphological evaluation using TEM. In-vitro drug release studies, cytotoxicity, apoptosis/necrosis, and cell cycle analysis were conducted using MCF-7 breast cancer cells. Also, an in-vivo assessment was carried out using EAC-bearing balb/c mice animal model to evaluate the effect of DOX/MET-loaded natural PRP and PRP-mimicked NCs on tumor weight, volume and growth biomarkers in addition to analyzing the immunohistopathology of the treated tissues. Results confirmed the development of CS/ALG-based PRP-mimicking NCs with a higher loading capacity of both drugs (DOX and MET) and smaller size (259.7 ± 19.3 nm) than natural PRP (489 ± 20.827 nm). Both in-vitro and in-vivo studies were in agreement and confirmed that MET synergized the anticancer activity of DOX against breast cancer. Besides, the developed LBL NCs successfully mimicked the PRP in improving the loaded drugs biological efficiency more than free drugs.

Recent advances of polymer based nanosystems in cancer management

Cancer is still one of the leading causes of death worldwide. Nanotechnology, particularly nanoparticle-based platforms, is at the leading edge of current cancer management research. Polymer-based nanosystems have piqued the interest of researchers owing to their many benefits over other conventional drug delivery systems. Polymers derived from both natural and synthetic sources have various biomedical applications due to unique qualities like porosity, mechanical strength, biocompatibility, and biodegradability. Polymers such as poly(lactic-co-glycolic acid) (PLGA), polycaprolactone (PCL), and polyethylene glycol (PEG) have been approved by the USFDA and are being researched for drug delivery applications. They have been reported to be potential carriers for drug loading and are used in theranostic applications. In this review, we have primarily focused on the aforementioned polymers and their conjugates. In addition, the therapeutic and diagnostic implications of polymer-based nanosystems have been briefly reviewed. Furthermore, the safety of the developed polymeric formulations is crucial, and we have discussed their biocompatibility in detail. This article also discusses recent developments in block co-polymer-based nanosystems for cancer treatment. The review ends with the challenges of clinical translation of polymer-based nanosystems in drug delivery for cancer therapy.

Polymer- and lipid-based gene delivery technology for CAR T cell therapy

Chimeric antigen receptor T cell (CAR T cell) therapy is a revolutionary approach approved by the FDA and EMA to treat B cell malignancies and multiple myeloma. The production of these T cells has been done through viral vectors, which come with safety concerns, high cost and production challenges, and more recently also through electroporation, which can be extremely cytotoxic. In this context, nanosystems can constitute an alternative to overcome the challenges associated with current methods, resulting in a safe and cost-effective platform. However, the barriers associated with T cells transfection show that the design and engineering of novel approaches in this field are highly imperative. Here, we present an overview from CAR constitution to transfection technologies used in T cells, highlighting the lipid- and polymer-based nanoparticles as a potential delivery platform. Specifically, we provide examples, strengths and weaknesses of nanosystem formulations, and advances in nanoparticle design to improve transfection of T cells. This review will guide the researchers in the design and development of novel nanosystems for next-generation CAR T therapeutics.

Well-Defined pH-Sensitive Self-Assembled Triblock Copolymer-Based Crosslinked Micelles for Efficient Cancer Chemotherapy

Delivery of chemotherapeutics to cancer cells using polymeric micelles is a promising strategy for cancer treatment. However, limited stability of micelles, premature drug release and off-target effect are the major obstacles that restrict the utilization of polymeric micelles as effective drug delivery systems. In this work, we addressed these issues through the innovative design of targeted pH-sensitive crosslinked polymeric micelles for chemotherapeutic delivery. A well-defined triblock copolymer, poly(ethylene glycol)-b-poly(2-hydroxyethyl methacrylate)-b-poly(butyl acrylate) (PEG-b-PHEMA-b-PBA), was synthesized by living radical polymerization, and then modified by using 4-pentenoic anhydride to incorporate pendant crosslinkable alkene groups in the middle block. The resulting copolymer underwent self-assembly in aqueous solution to form non-crosslinked micelles (NCMs). Subsequently, intramicellar thiol-ene crosslinking was performed by using 1,4-butanediol bis(3-mercaptopropionate) to give crosslinked micelles (CMs) with pH-sensitive crosslinks. The targeted CM (cRGD-DOX₁₀-CM5) was readily prepared by using tumor-targeting ligand cyclo(Arg-Gly-Asp-D-Phe-Cys) (cRGD) together with the 1,4-butanediol bis(3-mercaptopropionate) during the crosslinking step. The study of cumulative DOX release revealed the pH-sensitive feature of drug release from these CMs. An in vitro MTT assay revealed that NCMs and CMs are biocompatible with MCF 10A cells, and the samples exhibited significant therapeutic efficiency as compared to free DOX. Cellular uptake studies confirmed higher uptake of cRGD-DOX₁₀-CM5 by MCF 10A cancer cells via cRGD-receptor-mediated endocytosis as compared to the corresponding analogues without cRGD. These results indicate that such pH-responsive crosslinked PEG-b-PHEMA-b-PBA-based micelles are therapeutically effective against cancer cells and hold remarkable promise to act as smart drug delivery systems for cancer therapy.

Advances in the therapeutic delivery and applications of functionalized Pluronics: A critical review

Pluronic (PEO-PPO-PEO) block copolymers can form nano-sized micelles with a structure composed of a hydrophobic PPO core and hydrophilic PEO shell layer. Pluronics are U.S. Food and Drug Administration approved polymers, which are widely used for solubilization of drugs and their delivery, gene/therapeutic delivery, diagnostics, and tissue engineering applications due to their non-ionic properties, non-toxicity, micelle forming ability, excellent biocompatibility and biodegradability. Although Pluronics have been employed as drug carrier systems for several decades, numerous issues such as rapid dissolution, shorter residence time in biological media, fast clearance and weak mechanical strength have hindered their efficacy. Pluronics have been functionalized with pH-sensitive, biological-responsive moieties, antibodies, aptamers, folic acid, drugs, different nanoparticles, and photo/thermo-responsive hydrogels. These functionalization strategies enable Pluronics to act as stimuli responsive and targeted drug delivery vehicles. Moreover, Pluronics have emerged in nano-emulsion formulations and have been utilized to improve the properties of cubosomes, dendrimers and nano-sheets, including their biocompatibility and aqueous solubility. Functionalization of Pluronics results in the significant improvement of target specificity, loading capacity, biocompatibility of nanoparticles and stimuli responsive hydrogels for the promising delivery of a range of drugs. Therefore, this review presents an overview of all advancements (from the last 15 years) in functionalized Pluronics, providing a valuable tool for industry and academia in order to optimize their use in drug or therapeutic delivery, in addition to several other biomedical applications.

PEGylated ethyl cellulose micelles as a nanocarrier for drug delivery

Natural polymers provide a better alternative to synthetic polymers in the domain of drug delivery systems (DDSs) because of their renewability, biocompatibility, and low immunogenicity; therefore, they are being studied for the development of bulk/nanoformulations. Likewise, current methods for engineering natural polymers into micelles are in their infancy, and in-depth studies are required using natural polymers as controlled DDSs. Accordingly, in our present study, a new micellar DDS was synthesized using ethyl cellulose (EC) grafted with polyethylene glycol (PEG); it was characterized, its properties, cell toxicity, and hemocompatibility were evaluated, and its drug release kinetics were demonstrated using doxorubicin (DOX) as a model drug. Briefly, EC was grafted with PEG to form the amphiphilic copolymers EC-PEG1 and EC-PEG2 with varying PEG concentrations, and nano-micelles were prepared with and without the drug (DOX) via a dialysis method; the critical micelle concentrations (CMCs) were recorded to be 0.03 mg mL⁻¹ and 0.00193 mg mL⁻¹ for EC-PEG1 and EC-PEG2, respectively. The physicochemical properties of the respective nano-micelles were evaluated via various characterization techniques. The morphologies of the nano-micelles were analyzed via transmission electron microscopy (TEM), and the average size of the nano-micelles was recorded to be ∼80 nm. In vitro, drug release studies were done for 48 h, where 100% DOX release was recorded at pH 5.5 and 52% DOX release was recorded at pH 7.4 from the micelles. In addition, cytotoxicity studies suggested that DOX-loaded micelles were potent in killing MDA-MB-231 and MCF-7 cancer cells, and the blank micelles were non-toxic toward cancerous and normal cells. A cellular uptake study via fluorescence microscopy indicated the internalization of DOX-loaded micelles by cancer cells, delivering the DOX into the cellular compartments. Based on these studies, we concluded that the developed material should be studied further via in vivo studies to understand its potential as a controlled DDS to treat cancer.

Ethyl cellulose was developed as an amphiphilic polymer by PEGylation and fabricated as nanomicelles for delivery of active molecules. This polymeric system can be used as next generation nano drug delivery system (nanoDDS) for cancer therapy.

Enzyme-instructed hybrid nanogel/nanofiber oligopeptide hydrogel for localized protein delivery

Enzyme-catalysis self-assembled oligopeptide hydrogel holds great interest in drug delivery, which has merits of biocompatibility, biodegradability and mild gelation conditions. However, its application for protein delivery is greatly limited by inevitable degradation of enzyme on the encapsulated proteins leading to loss of protein activity. Moreover, for the intracellularly acted proteins, cell membrane as a primary barrier hinders the transmembrane delivery of proteins. The internalized proteins also suffer from acidic and enzymatic degradation in endosomes and lysosomes. We herein develop a protease-manipulated hybrid nanogel/nanofiber hydrogel for localized delivery of intracellularly acted proteins. The embedded polymeric nanogels (CytoC/aNGs) preserve activity of cytochrome c (CytoC) that is an intracellular activator for cell apoptosis as a model protein against proteolysis, and do not affect the gelation properties of the protease-catalysis assembled hydrogels. The injectable hydrogel (CytoC/aNGs/Gel) serves as a reservoir to enhance intratumoral retention and realize sustainable release of CytoC/aNGs. The released CytoC/aNGs increase cellular uptake of CytoC and enhance its intracellular delivery to its target site, cytoplasm, resulting in favorable apoptosis-inducing and cytotoxic effects. We show that a single local administration of CytoC/aNGs/Gel efficiently inhibit the tumor growth in the breast tumor mouse model.

A pH/ROS cascade-responsive and self-accelerating drug release nanosystem for the targeted treatment of multi-drug-resistant colon cancer

The efficacy of chemotherapeutic agents for colon cancer treatment is limited by multidrug resistance (MDR) and insufficient intracellular release of the administered nanomedicine. To overcome these limitations, we constructed a pH/ROS cascade-responsive and self-accelerating drug release nanoparticle system (PLP-NPs) for the treatment of multidrug-resistant colon cancer. The PLP-NPs comprised a reactive oxygen species (ROS)-sensitive polymeric paclitaxel (PTX) prodrug (DEX-TK-PTX), a pH-sensitive poly(l-histidine) (PHis), and beta-lapachone (Lapa), a ROS-generating agent. We found that PLP-NPs could accumulate in tumor tissue through enhancement of the permeability and retention (EPR) effect, and were subsequently internalized by cancer cells via the endocytic pathway. Within the acidic endo-lysosomal environment, PHis protonation facilitated the escape of the PLP-NPs from the lysosome and release of Lapa. The released Lapa generated a large amount of ROS, consumed ATP, and downregulated P-glycoprotein (P-gp) production through the activity of NQO1, an enzyme that is specifically overexpressed in tumor cells. In addition, the generated ROS promoted the release of PTX from DEX-TK-PTX to kill cancer cells, while ATP depletion inhibited P-gp-mediated MDR. In vitro and in vivo experiments subsequently confirmed that PLP-NPs induced tumor-specific cytotoxicity and overcame the MDR of colon cancer. Our findings indicate that the use of the PLP-NPs system represents a promising strategy to counter MDR in the treatment of colon cancer.

A doxorubicin-platinum conjugate system: impacts on PI3K/AKT actuation and apoptosis in breast cancer cells

In recent years, the development of a nano-conjugate system for drug delivery applications has gained attention among researchers. Keeping this in mind, in this study, we developed a doxorubicin-platinum conjugate system that targeted breast cancer cell lines. To achieve this, we developed platinum nanoparticles using polyvinylpyrrolidone (PVP). High resolution-transmission electron microscopy (HR-TEM) revealed the occurrence of octopod-shaped platinum nanoparticles. Subsequently, doxorubicin (DOX) was conjugated on the surface of the as-prepared platinum octopods via an in situ stirring method. The physicochemical characterization of the doxorubicin-platinum conjugate system revealed that the PVP of PtNPs interacts with the NH2 group of doxorubicin via electrostatic interaction/hydrogen bonding. Besides, the doxorubicin-platinum conjugate system exhibited a sustained drug release profile within the cancer cells. Furthermore, the evaluation of the in vitro anticancer efficacy of the doxorubicin-platinum conjugate system in breast cancer cells (MCF-7 and MDA-MB-231) unveiled the induction of apoptosis via intracellular ROS and DNA damage, rather than free DOX and PtNPs. Remarkably, we also perceived that the doxorubicin-platinum conjugate system was strong enough to down-regulate the PI3K/AKT signalling pathway. As a result, the tumour suppressor gene PTEN was activated, which led to the stimulation of a mitochondrion-based intrinsic apoptotic pathway and its downstream caspases, triggering cell death. Hence, our findings suggested that a biologically stable doxorubicin-platinum conjugate system could be an imperative therapeutic agent for anticancer therapy in the near future.

Inclusion of IR-820 into Soybean-Phosphatides-Based Nanoparticles for Near-Infrared-Triggered Release and Endolysosomal Escape in HaCaT Keratinocytes at Insignificant Cytotoxic Level

PURPOSE

The degradation of drugs within endolysosomes has been widely addressed as a cause of poor bioavailability. One of the strategies to allow molecules to escape from a destructive fate is to introduce a photosensitizing moiety into a drug carrier enabling the permeabilization of endosomes and endolysosomes upon irradiation. This paper presents an alternative delivery nanosystem composed of cost-effective soybean phosphatides mixed with IR-820, a near-infrared (NIR) sensitizer, to load various active compounds and trigger an endolysosomal escape with a low cytotoxic effect.

METHODS

IR-820-incorporated phosphatides-based nanoparticles were formulated using a thin-film hydration method to encapsulate different molecular probes and a drug model. The nanoparticles were characterized in vitro using dynamic light scattering, transmission electron microscopy, as well as ultraviolet-visible and fluorescence spectroscopy techniques. The NIR-corresponding generation of the photochemical products, the content release, and the cytotoxicity toward the HaCaT keratinocyte cell line were evaluated. The cellular internalization and endolysosomal escape were monitored using a cytochemical marker and fluorescent probes with a colocalization analysis.

RESULTS

The IR-820-combined nanoparticles revealed the NIR-triggered changes in the singlet oxygen presence, nanoparticle architecture, and release rate without being cytotoxic. Additionally, the nanoplatform appeared to enhance cellular uptake of the macromolecules. The localization of the cytochemical marker and the colocalization analysis on the fluorescence signals of the encapsulated fluorophore and the lysosome-labeling reporter implied the transient endolysosomal escape of the cargo within the HaCaT cells after NIR irradiation.

CONCLUSION

The inclusion of IR-820 into a soybean-phosphatides base ingredient provides NIR responsiveness, particularly the endolysosomal escape of the payload, to the formulated nanoparticles, while preserving the beneficial properties as a drug carrier. This alternative delivery nanomedicine system has future potential to provide high bioavailability of cytosolic drugs utilizing time- and spatial-controllable NIR triggerability as well as the synergistic therapeutic effects with NIR-biomodulation.

Self-Assembly of Amphiphilic Compounds as a Versatile Tool for Construction of Nanoscale Drug Carriers

This review focuses on synthetic and natural amphiphilic systems prepared from straight-chain and macrocyclic compounds capable of self-assembly with the formation of nanoscale aggregates of different morphology and their application as drug carriers. Since numerous biological species (lipid membrane, bacterial cell wall, mucous membrane, corneal epithelium, biopolymers, e.g., proteins, nucleic acids) bear negatively charged fragments, much attention is paid to cationic carriers providing high affinity for encapsulated drugs to targeted cells. First part of the review is devoted to self-assembling and functional properties of surfactant systems, with special attention focusing on cationic amphiphiles, including those bearing natural or cleavable fragments. Further, lipid formulations, especially liposomes, are discussed in terms of their fabrication and application for intracellular drug delivery. This section highlights several features of these carriers, including noncovalent modification of lipid formulations by cationic surfactants, pH-responsive properties, endosomal escape, etc. Third part of the review deals with nanocarriers based on macrocyclic compounds, with such important characteristics as mucoadhesive properties emphasized. In this section, different combinations of cyclodextrin platform conjugated with polymers is considered as drug delivery systems with synergetic effect that improves solubility, targeting and biocompatibility of formulations.

PH-Responsive, Cell-Penetrating, Core/Shell Magnetite/Silver Nanoparticles for the Delivery of Plasmids: Preparation, Characterization, and Preliminary In Vitro Evaluation

Over the past decade, gene therapies have attracted much attention for the development of treatments for various conditions, including cancer, neurodegenerative diseases, protein deficiencies, and autoimmune disorders. Despite the benefits of this approach, several challenges are yet to be solved to reach clinical implementation. Some of these challenges include low transfection rates, limited stability under physiological conditions, and low specificity towards the target cells. An avenue to overcome such issues is to deliver the therapies with the aid of potent cell-penetrating vectors. Non-viral vectors, such as nanostructured materials, have been successfully tested in drug and gene delivery. Here, we propose the development and in vitro evaluation of a nanostructured cell-penetrating vehicle based on core/shell, magnetite/silver nanoparticles. A subsequent conjugation of a pH-responsive polymer was used to assure that the vehicle can carry and release circular DNA. Additionally, the translocating peptide Buforin II was conjugated with the aid of a polyether amine polymer to facilitate translocation and endosome escape. The obtained nanobioconjugates (magnetite/silver-pDMAEMA-PEA-BUFII) were characterized by UV-Vis spectrophotometry, dynamic light scattering (DLS), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope equipped with energy dispersive spectroscopy (SEM+EDS), and transmission electron microscopy (TEM). They were also encapsulated in lecithin liposomes to form magnetoliposomes. The cell viability of Vero cells in the presence of the nanobioconjugates was above 95% and declined to 80% for the magnetoliposomes. The hemolytic tendency of nanobioconjugates and magnetoliposomes was below 10%, while the platelet aggregation approached that of the negative control (i.e., 35%). Cytoplasm coverage values of about 50% for both Vero and neuroblastoma cells confirmed significant cell penetration. Pearson's correlation coefficients for both cell lines allowed us to estimate 20-40% colocalization of the nanobioconjugates with lysotracker green, which implied high levels of endosomal escape. The developed vehicles were also capable of loading around 16% of the added DNA and releasing such cargo with 8% efficiency. The developed nanoplatform holds a significant promise to enable highly efficient gene therapies as it overcomes some of the major issues associated with their eventual translation to the pre-clinical and clinical scale.

Tumor extracellular pH-sensitive polymeric nanocarrier-grafted platinum(iv) prodrugs for improved intracellular delivery and cytosolic reductive-triggered release

Extracellular pH-sensitive Pt(iv)-based nanodrugs enable preferential toxicity to tumor cells via a selectively endocytosed and triggered drug release strategy.

Nanotargeted agents: an emerging therapeutic strategy for breast cancer

Breast cancer is the most common female cancer worldwide and represents 12% of all cancer cases. Improvements in survival rates are largely attributed to improved screening and diagnosis. Conventional chemotherapy remains an important treatment option but it is beset with poor cell selectivity, serious side effects and resistance. Nanoparticle drug delivery systems bring promising opportunities to breast cancer treatment. They may improve chemotherapy by targeting drugs to tumors, generating high drug concentrations at tumors providing slow release of the drug, increased drug stability and concomitant reductions in side effects. The nanotechnology-based drug delivery approaches and the current research and application status of nano-targeted agents for breast cancer are discussed in this review to provide a basis for further study on targeted drug delivery systems.

Cationic block amphiphiles show anti-mitochondrial activity in multi-drug resistant breast cancer cells

Currently, there are limited treatment options for multi-drug resistant breast cancer. Lipid-modified cationic peptides have the potential to reach the mitochondria, which are attractive targets for the treatment of multi-drug resistant (MDR) breast cancer; yet, little is known about their mitochondrial targeting and anti-cancer activity. Interestingly, lipid-modified cationic peptides, typically used as gene transfection agents, exhibit similar structural features to mitochondrial targeted peptides. Using octahistidine-octaarginine (H₈R₈) as a model cationic peptide for cell penetration and endosomal escape, we explored the anti-cancer potential of lipid-modified cationic peptides as a function of amphiphilicity, biodegradability and lipid structure. We found that cationic peptides modified with a lipid that is at least 12 carbons in length exhibit potent anti-cancer activity in the low micromolar range in both EMT6/P and EMT6/AR-1 breast cancer cells. Comparing degradable and non-degradable linkers, as well as L- and D-amino acid sequences, we found that the anti-cancer activity is mostly independent of the biodegradation of the lipid-modified cationic peptides. Two candidates, stearyl-H₈R₈ (Str-H₈R₈) and vitamin E succinate-H₈R₈ (VES-H₈R₈) were cytotoxic to cancer cells by mitochondria depolarization. We observed increased reactive oxygen species (ROS) production, reduced cell bioenergetics and drug efflux, triggering apoptosis and G1 cell cycle arrest. Compared to Str-H₈R₈, VES-H₈R₈ showed enhanced cancer cell selectivity and drug efflux inhibition, thereby serving as a potential novel therapeutic agent. This study deepens our understanding of lipid-modified cationic peptides and uncovers their potential in multi-drug resistant breast cancer.

Novel facile thermosensitive hydrogel as sustained and controllable gene release vehicle for breast cancer treatment

The current research process in gene therapy for cancer treatment has brought much attention due to its great potential for both inherited and acquired diseases. Precise accumulation in target site and on-demand release of drug is critical factors for the efficient gene therapy. Since the delivery of suitable gene largely depends on the delivery carrier, the design of suitable gene delivery vehicle for the sustained gene release in target site are attracting increasingly interest among the researchers. In this report, an effective and relatively convenient gene delivery platform is developed by the electrostatic interaction between negative charged survivin antisense oligonucleotide (Sur-ASON) and positive charged PHB-b-PDMAEMA (PHB-P) co-polymer and then the induction of thermosensitive PF127 hydrogel. The prepared hydrogel could achieve a sustained gene release property in the tumor region after injection, thus to enhance the effect of Survivin antisense oligonucleotide and inhibit P-gp impaired drug uptake simultaneously. In vivo anti-tumor efficacy and H&E staining indicated that Sur-ASON/PHB-P/PF127 hydrogel was greatly effective in enhancing the treatment effects of Sur-ASON while reducing the degradation and the possible adverse side effects, and this novel hydrogel could achieve the controlled gene release up to maximum 16 days. The aforementioned properties indicated that the novel hydrogel could be applied as a promising and convenient anti-cancer agent for anticancer therapy with minimum injection frequency to possibly increase patient compliance.

A two-photon fluorophore labeled multi-functional drug carrier for targeting cancer therapy, inflammation restraint and AIE active bioimaging

Functional drug carriers with simultaneous effective delivery of therapeutic agents to target sites and great imaging ability have attracted great attention in nanomedicine research.

Finding the ideal polyethylenimine-plasmid DNA system for co-delivery of payloads in cancer therapy

Researchers still hold for the development of a safety and advanced delivery system able of efficient therapeutic action. The co-delivery of different payloads is part of this strategy and has already demonstrated to be a valuable tool against the most severe diseases. In the pursuit of an "ideal" drug/gene co-delivery vector for cancer therapy, we present a complete comparison study of different morphology and molecular weight polyethylenimine (PEI)/p53 encoding plasmid DNA (pDNA) polyplexes. Besides pDNA, also methotrexate (MTX) has been loaded into PEI/pDNA nanoparticles. The polyplexes have been characterized in terms of morphology, size, surface charges, loading/encapsulation efficiencies and toxicity. Although the nature of PEI can influence these properties, they deeply vary with the polymer nitrogen to pDNA phosphate (N/P) ratio. The transfection of HeLa cells mediated by PEI/pDNA/MTX vectors leads to both the release of MTX and the p53 protein expression. Modelling of MTX release kinetics brings valuable information concerning drug delivery mechanism. Moreover, the success of transfection is dependent on the nature of PEI and, mainly, on the N/P ratio used in the formulation of polyplexes. This work represents a great contribution for the design and development of innovative PEI based carriers for the most challenging biomedical applications.

Highly functionalized pyrrolidine analogues: stereoselective synthesis and caspase-dependent apoptotic activity

Spiropyrrolidines were synthesized employing a new class of azomethine ylide for the first time and were tested for their anticancer activity, where the cell death mechanism revealed that it is occurring through the caspase-3 dependent pathway.

ATRP Fabricated and Short Chain Polyethylenimine Grafted Redox Sensitive Polymeric Nanoparticles for Codelivery of Anticancer Drug and siRNA in Cancer Therapy

To overcome the limitations of conventional chemotherapy, nanoparticle-mediated combinatorial delivery of siRNA and drugs represents a new approach to overcome its associated side effects. Designing safe and efficient vehicles for their codelivery has emerged as a potential challenge in the clinical translation of these formulations. Herein, we have demonstrated a novel "two-in-one" polyplex nanosystem developed from redox sensitive, short chain polyethylenimine modified poly[(poly(ethylene)glycol methacrylate]-s-s-polycaprolactone copolymer synthesized by atom-transfer free-radical polymerization (ATRP), which can deliver doxorubicin and polo-like kinase I (plk1) siRNA, simultaneously for an enhanced chemotherapeutic effect. The nanoparticles were found to be stable at physiological buffer with and without fetal bovine serum (FBS). The developed polymeric nanosystem was found to be biocompatible and hemocompatible in vitro and in vivo at repeated dose administrations. The polymer could easily self-assemble into ∼100 nm spherical nanoparticles with enhanced doxorubicin loading (∼18%) and effective siRNA complexation at a polymer to siRNA weight ratio of 15. The doxorubicin loaded nanoparticles exhibited ∼4-fold higher drug release in endosomal pH (pH 5) containing 10 mmol of GSH compared to pH 7.4, depicting their redox-sensitive behavior. The polyplexes were capable of delivering both cargos simultaneously to cancer cells in vitro as observed by their excellent colocalization in the cytoplasm of MDA-MB-231 and HeLa cells using confocal laser microscopy. Moreover, in vitro transfection of the cells with polyplexes exhibited 50-70% knockdown of plk1-mRNA expression in both cell lines. In vivo administration of the drug loaded polyplexes to EAT tumor bearing (EAT, Ehrlich ascites tumor) Swiss albino mice showed a ∼29-fold decrease in percent tumor volume in comparison to the control group. The results highlight the therapeutic potential of the polyplexes as a combined delivery of doxorubicin and plk1-siRNA in cancer therapy.

Combinatorial delivery of superparamagnetic iron oxide nanoparticles (γFe2O3) and doxorubicin using folate conjugated redox sensitive multiblock polymeric nanocarriers for enhancing the chemotherapeutic efficacy in cancer cells

Redox sensitive, folate conjugated multiblock polymeric system of (-PLGA-PEG-PLGA-urethane-ss-) demonstrated self-assembly into stable nanoplatforms. The polymeric nanocarriers were encapsulated with doxorubicin and highly crystalline γFe₂O₃ superparamagnetic iron oxide nanoparticles (SPIONs), for co-delivery of the same to cancer cells, with average particle size of ~170nm and zeta potential of ~-33mV. Furthermore, the designed formulation was evaluated for protein adsorption, hemo-cytocompatibility and stability. Glutathione (GSH) induced redox sensitivity of the nanocarriers was depicted by ~4.47 fold increase in drug release in the presence of 10mM GSH. In vitro cellular uptake studies of the designed nanocarriers showed synergistic cytotoxic effect in folate overexpressing cells (HeLa and MDA-MB-231), after subjecting the cells to radio frequency (RF) induced hyperthermia (~43°C). Negligible effect of the combinatorial therapy was observed in normal cells (L929). The developed polymeric system depicted facile synthesis, reproducibility and potential for achieving combinatorial and targeted delivery of drug and SPIONs to cancer cells. This combinatorial approach can help in achieving better therapeutic effect with minimal side effects of chemotherapy.

A general method to regenerate arrayed gold microelectrodes for label-free cell assay

We developed a method to regenerate arrayed gold microelectrodes equipped for a commercial label-free cell analyzer. The regeneration process includes efficient treatment of the gold surface with trypsin (0.25%, v/v) digestion, rinsing with ethanol and deionized water and spinning steps. The proposed method ensured complete regeneration and repeated usage of gold microchips up to 4 times for the real-time electric impedance measurement of anti-cancer drug cytotoxicity.

In vivo tumor targeting and anti-tumor effects of 5-fluororacil loaded, folic acid targeted quantum dot system

In this study, we modulated the anti-cancer efficacy of 5-Fluorouracil (5-FU) using a carrier system with enhanced targeting efficacy towards folate receptors (FRs) expressing malignant tissues. The 5-FU drug was loaded onto Mn-ZnS quantum dots (QDs) encapsulated with chitosan (CS) biopolymer and conjugated with folic acid (FA) based on a simple wet chemical method. The formation of 5-FU drug loaded composite was confirmed using Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC). Furthermore, the in vivo biodistribution and tumor targeting specificity of the 5-FU@FACS-Mn:ZnS in the tumor-bearing mice was conducted based on the Zn(2+) tissue bioaccumulation using inductively coupled plasma (ICP) spectroscopy. In addition to the characterization, the in vitro release profile of 5-FU from the conjugates investigated under diffusion controlled method demonstrated a controlled release behaviour as compared against the release behaviour of free 5-FU drug. The as-synthesized 5-FU@FACS-Mn:ZnS nanoparticle (NP) systemically induced higher level of apoptosis in breast cancer cells in vitro as compared to cells treated with free 5-FU drug following both cell cycle and annexin assays, respectively. Also, the in vivo toxicity assessment of the 5-FU@FACS-Mn:ZnS NPs as compared to the control did not cause any significant increase in the activities of the liver and kidney function biomarkers, malondialdehyde (MDA) and nitric oxide (NO) levels. However, based on the FA-FRs chemistry, the 5-FU@FACS-Mn:ZnS NPs specifically accumulated in the tumor of the tumor-bearing mice and thus contributed to the smaller tumor size and less event of metastasis was observed in the lungs when compared to the tumor-bearing mice groups treated with the free 5-FU drug. In summary, the results demonstrated that the 5-FU@FACS-Mn:ZnS QDs exhibits selective anti-tumor effect in MDA-MB231 breast cancer cells in vitro and 4TI breast cancer cells in vivo, providing a blueprint for improving the 5-FU efficacy and tumor targeting specificity with limited systemic toxicity.

Smart micro/nanoparticles in stimulus-responsive drug/gene delivery systems

New achievements in the realm of nanoscience and innovative techniques of nanomedicine have moved micro/nanoparticles (MNPs) to the point of becoming actually useful for practical applications in the near future. Various differences between the extracellular and intracellular environments of cancerous and normal cells and the particular characteristics of tumors such as physicochemical properties, neovasculature, elasticity, surface electrical charge, and pH have motivated the design and fabrication of inventive "smart" MNPs for stimulus-responsive controlled drug release. These novel MNPs can be tailored to be responsive to pH variations, redox potential, enzymatic activation, thermal gradients, magnetic fields, light, and ultrasound (US), or can even be responsive to dual or multi-combinations of different stimuli. This unparalleled capability has increased their importance as site-specific controlled drug delivery systems (DDSs) and has encouraged their rapid development in recent years. An in-depth understanding of the underlying mechanisms of these DDS approaches is expected to further contribute to this groundbreaking field of nanomedicine. Smart nanocarriers in the form of MNPs that can be triggered by internal or external stimulus are summarized and discussed in the present review, including pH-sensitive peptides and polymers, redox-responsive micelles and nanogels, thermo- or magnetic-responsive nanoparticles (NPs), mechanical- or electrical-responsive MNPs, light or ultrasound-sensitive particles, and multi-responsive MNPs including dual stimuli-sensitive nanosheets of graphene. This review highlights the recent advances of smart MNPs categorized according to their activation stimulus (physical, chemical, or biological) and looks forward to future pharmaceutical applications.

Tumor-penetrating peptide modified and pH-sensitive polyplexes for tumor targeted siRNA delivery

The pH-sensitive copolymer enhanced the lysosome escape of polyplexes and modification of iRGD endowed the polyplexes with effective intratumoral delivery and high transfection efficiency.

ROP and ATRP Fabricated Dual Targeted Redox Sensitive Polymersomes Based on pPEGMA-PCL-ss-PCL-pPEGMA Triblock Copolymers for Breast Cancer Therapeutics

To minimize cardiotoxicity and to increase the bioavailability of doxorubicin, polymersomes based on redox sensitive amphiphilic triblock copolymer poly(polyethylene glycol methacrylate)-poly(caprolactone)-s-s-poly(caprolactone)-poly(polyethylene glycol methacrylate) (pPEGMA-PCL-ss-PCL-pPEGMA) with disulfide linkage were designed and developed. The polymers were synthesized by ring opening polymerization (ROP) of ε-caprolactone followed by atom transfer radical polymerization (ATRP) of PEGMA. The triblock copolymers demonstrated various types of nanoparticle morphologies by varying hydrophobic/hydrophilic content of polymer blocks, with PEGMA content of ∼18% in the triblock copolymer leading to the formation of polymersomes in the size range ∼150 nm. High doxorubicin loading content of ∼21% was achieved in the polymersomes. Disulfide linkages were incorporated in the polymeric backbone to facilitate degradation of the nanoparticles by the intracellular tripeptide glutathione (GSH), leading to intracellular drug release. Release studies showed ∼59% drug release in pH 5.5 in the presence of 10 mM GSH, whereas only ∼19% was released in pH 7.4. In cellular uptake studies, dual targeted polymersomes showed ∼22-fold increase in cellular uptake efficiency in breast cancer cell lines (BT474 and MCF-7) as compared to nontargeted polymersomes with higher apoptosis rates. In vivo studies on Ehrlich's ascites tumor (EAT) bearing Swiss albino mouse model showed ∼85% tumor regression as compared to free doxorubicin (∼42%) without any significant cardiotoxicity associated with doxorubicin. The results indicate enhanced antitumor efficacy of the redox sensitive biocompatible nanosystem and shows promise as a potential drug nanocarrier in cancer therapeutics.

Synthesis and biological evaluation of dual functionalized glutathione sensitive poly(ester-urethane) multiblock polymeric nanoparticles for cancer targeted drug delivery

Dual targeted redox responsive doxorubicin loaded polymeric nanoparticles were prepared and evaluated for anticancer efficacy.

Preparation of biocompatible and photostable PEGylated red fluorescent nanoparticles for cellular imaging

Biocompatible and photostable PEGylated red fluorescent nanoparticles were preparedviasurface-initiated ATRP and their cellular imaging application was successfully demonstrated.