Characterization of novel multifunctional cationic polymeric liposomes formed from octadecyl quaternized carboxymethyl chitosan/cholesterol and drug encapsulation

Exploring the diverse applications of Carbohydrate macromolecules in food, pharmaceutical, and environmental technologies

Carbohydrates are a class of macromolecules that has significant potential across several domains, including the organisation of genetic material, provision of structural support, and facilitation of defence mechanisms against invasion. Their molecular diversity enables a vast array of essential functions, such as energy storage, immunological signalling, and the modification of food texture and consistency. Due to their rheological characteristics, solubility, sweetness, hygroscopicity, ability to prevent crystallization, flavour encapsulation, and coating capabilities, carbohydrates are useful in food products. Carbohydrates hold potential for the future of therapeutic development due to their important role in sustained drug release, drug targeting, immune antigens, and adjuvants. Bio-based packaging provides an emerging phase of materials that offer biodegradability and biocompatibility, serving as a substitute for traditional non-biodegradable polymers used as coatings on paper. Blending polyhydroxyalkanoates (PHA) with carbohydrate biopolymers, such as starch, cellulose, polylactic acid, etc., reduces the undesirable qualities of PHA, such as crystallinity and brittleness, and enhances the PHA's properties in addition to minimizing manufacturing costs. Carbohydrate-based biopolymeric nanoparticles are a viable and cost-effective way to boost agricultural yields, which is crucial for the increasing global population. The use of biopolymeric nanoparticles derived from carbohydrates is a potential and economically viable approach to enhance the quality and quantity of agricultural harvests, which is of utmost importance given the developing global population. The carbohydrate biopolymers may play in plant protection against pathogenic fungi by inhibiting spore germination and mycelial growth, may act as effective elicitors inducing the plant immune system to cope with pathogens. Furthermore, they can be utilised as carriers in controlled-release formulations of agrochemicals or other active ingredients, offering an alternative approach to conventional fungicides. It is expected that this review provides an extensive summary of the application of carbohydrates in the realms of food, pharmaceuticals, and environment.

Liposomal nanocarriers containing siRNA as small molecule-based drugs to overcome cancer drug resistance

This review discusses the application of nanoliposomes containing siRNA/drug to overcome multidrug resistance for all types of cancer treatments. As drug resistance-associated factors are overexpressed in many cancer cell types, pumping chemotherapy drugs out of the cytoplasm leads to an inadequate therapeutic response. The siRNA/drug-loaded nanoliposomes are a promising approach to treating multidrug-resistant cancer, as they can effectively transmit a small-molecule drug into the target cytoplasm, ensuring that the drug binds efficiently. Moreover, nanoliposome-based therapeutics with advances in nanotechnology can effectively deliver siRNA to cancer cells. Overall, nanoliposomes have the potential to effectively deliver siRNA and small-molecule drugs in a targeted manner and are thus a promising tool for the treatment of cancer and other diseases.

Stimuli-responsive liposomal nanoformulations in cancer therapy: Pre-clinical & clinical approaches

The site-specific delivery of antitumor agents is of importance for providing effective cancer suppression. Poor bioavailability of anticancer compounds and the presence of biological barriers prevent their accumulation in tumor sites. These obstacles can be overcome using liposomal nanostructures. The challenges in cancer chemotherapy and stimuli-responsive nanocarriers are first described in the current review. Then, stimuli-responsive liposomes including pH-, redox-, enzyme-, light-, thermo- and magneto-sensitive nanoparticles are discussed and their potential for delivery of anticancer drugs is emphasized. The pH- or redox-sensitive liposomes are based on internal stimulus and release drug in response to a mildly acidic pH and GSH, respectively. The pH-sensitive liposomes can mediate endosomal escape via proton sponge. The multifunctional liposomes responsive to both redox and pH have more capacity in drug release at tumor site compared to pH- or redox-sensitive alone. The magnetic field and NIR irradiation can be exploited for external stimulation of liposomes. The light-responsive liposomes release drugs when they are exposed to irradiation; thermosensitive-liposomes release drugs at a temperature of >40 °C when there is hyperthermia; magneto-responsive liposomes release drugs in presence of magnetic field. These smart nanoliposomes also mediate co-delivery of drugs and genes in synergistic cancer therapy. Due to lack of long-term toxicity of liposomes, they can be utilized in near future for treatment of cancer patients.

Chemical Modification of Chitosan for Developing Cancer Nanotheranostics

Cancer is a worldwide public health issue that has not been conquered. Theranostics, the combination of a therapeutic drug and imaging agent in one formulation using nanomaterials, has been developed to better cure cancer in recent years. Although diverse biomaterials have been applied in cancer theranostics, chitosan (CS), a natural polysaccharide bearing easy modification sites with excellent biocompatibility and biodegradability, shows great potential for developing cancer nanotheranostics. In this review, we seek to describe the chemical functionalities of CS used in cancer theranostics and their synthesis methods. We also present recent discoveries and research progresses on how the CS functionalization could improve the delivery efficiency of CS-based nanotheranostics. Finally, we report several case studies about the application of CS-based nanotheranostics. This paper focuses on the strategies to construct CS-based theranostics systems via chemical routes and highlights their applications in cancer treatment, which can provide useful references for further studies.

New phase therapeutic pursuits for targeted drug delivery in glioblastoma multiforme

Glioblastoma multiforme (GBM) is known as the most aggressive and prevalent brain tumor with a high mortality rate. It is reported in people who are as young as 10 years old to as old as over 70 years old, exhibiting inter and intra tumor heterogeneity. There are several genomic and proteomic investigations that have been performed to find the unexplored potential targets of the drug against GBM. Therefore, certain effective targets have been taken to further validate the studies embarking on the robustness in the field of medicinal chemistry followed by testing in clinical trials. Also, The Cancer Genome Atlas (TCGA) project has identified certain overexpressed targets involved in the pathogenesis of GBM in three major pathways, i.e., tumor protein 53 (p53), retinoblastoma (RB), and receptor tyrosine kinase (RTK)/rat sarcoma virus (Ras)/phosphoinositide 3-kinase (PI3K) pathways. This review focuses on the compilation of recent developments in the fight against GBM thus, directing future research into the elucidation of pathogenesis and potential cure for GBM. Also, it highlights the potential biomarkers that have undergone extensive research and have promising prognostic and predictive values. Additionally, this manuscript analyses the advent of gene therapy and immunotherapy, unlocking the way to consider treatment approaches other than, or in addition to, conventional chemo-radiation therapies. This review study encompasses all the relevant research studies associated with the pathophysiology, occurrence, diagnostic tools, and therapeutic intervention for GBM. It highlights the evolution of various therapeutic perspectives against GBM from the most conventional form of radiotherapy to the recent advancement of gene/cell/immune therapy. Further, the review focuses on various targeted therapies for GBM including chemotherapy sensitization, radiotherapy, nanoparticles based, immunotherapy, cell therapy, and gene therapy which would offer a comprehensive account for exploring several facets related to GBM prognostics.

Liposomes: Structure, Biomedical Applications, and Stability Parameters With Emphasis on Cholesterol

Liposomes are essentially a subtype of nanoparticles comprising a hydrophobic tail and a hydrophilic head constituting a phospholipid membrane. The spherical or multilayered spherical structures of liposomes are highly rich in lipid contents with numerous criteria for their classification, including structural features, structural parameters, and size, synthesis methods, preparation, and drug loading. Despite various liposomal applications, such as drug, vaccine/gene delivery, biosensors fabrication, diagnosis, and food products applications, their use encounters many limitations due to physico-chemical instability as their stability is vigorously affected by the constituting ingredients wherein cholesterol performs a vital role in the stability of the liposomal membrane. It has well established that cholesterol exerts its impact by controlling fluidity, permeability, membrane strength, elasticity and stiffness, transition temperature (Tm), drug retention, phospholipid packing, and plasma stability. Although the undetermined optimum amount of cholesterol for preparing a stable and controlled release vehicle has been the downside, but researchers are still focused on cholesterol as a promising material for the stability of liposomes necessitating explanation for the stability promotion of liposomes. Herein, the prior art pertaining to the liposomal appliances, especially for drug delivery in cancer therapy, and their stability emphasizing the roles of cholesterol.

Quaternary Ammonium Chitosans: The Importance of the Positive Fixed Charge of the Drug Delivery Systems

As a natural polysaccharide, chitosan has good biocompatibility, biodegradability and biosecurity. The hydroxyl and amino groups present in its structure make it an extremely versatile and chemically modifiable material. In recent years, various synthetic strategies have been used to modify chitosan, mainly to solve the problem of its insolubility in neutral physiological fluids. Thus, derivatives with negative or positive fixed charge were synthesized and used to prepare innovative drug delivery systems. Positively charged conjugates showed improved properties compared to unmodified chitosan. In this review the main quaternary ammonium derivatives of chitosan will be considered, their preparation and their applications will be described to evaluate the impact of the positive fixed charge on the improvement of the properties of the drug delivery systems based on these polymers. Furthermore, the performances of the proposed systems resulting from in vitro and ex vivo experiments will be taken into consideration, with particular attention to cytotoxicity of systems, and their ability to promote drug absorption.

Application of Paclitaxel-loaded EGFR Peptide-conjugated Magnetic Polymeric Liposomes for Liver Cancer Therapy

Developing the methodologies that allow for safe and effective delivery of therapeutic drugs to target sites is a very important research area in cancer therapy. In this study, polyethylene glycol (PEG)-coated magnetic polymeric liposome (MPL) nanoparticles (NPs) assembled from octadecyl quaternized carboxymethyl chitosan (OQC), PEGylated OQC, cholesterol, and magnetic NPs, and functionalized with epithelial growth factor receptor (EGFR) peptide, were successfully prepared for in-vivo liver targeting. The two-step liver targeting strategy, based on both magnetic force and EGFR peptide conjugation, was evaluated in a subcutaneous hepatocellular carcinoma model of nude mouse. The results showed that EGFR-conjugated MPLs not only accumulated in the liver by magnetic force, but could also diffuse into tumor cells as a result of EGFR targeting. In addition, paclitaxel (PTX) was incorporated into small EGFR-conjugated MPLs (102.0±0.7 nm), resulting in spherical particles with high drug encapsulation efficiency (>90%). The use of the magnetic targeting for enhancing the transport of PTX-loaded EGFR-conjugated MPLs to the tumor site was further confirmed by detecting PTX levels. In conclusion, PTX-loaded EGFR-conjugated MPLs could potentially be used as an effective drug delivery system for targeted liver cancer therapy.

Self-assembly of strawberry-like organic–inorganic hybrid particle clusters with directionally distributed bimetal and facile transformation of the core and corona

Controllable structure of organic–inorganic hybrid particle clusters were successfully fabricated by self-assembly which derived from the strong interaction between carboxyl groups of the organic particles and amino groups of the inorganic particles.

The Why, Where, Who, How, and What of the vesicular delivery systems

Though vesicular delivery systems have been widely explored and reviewed, no comprehensive review exists that covers their development from the inception of the concept to its culmination in the form of regulated marketed formulations. With the advancement of scientific research in the field of nanomedicine, certain category of vesicular delivery systems have successfully reached the global market. Despite extensive research and highly encouraging results in a plethora of pathological conditions in the preclinical studies, translation of these nanomedicines from laboratory to market has been very limited. Aim of this review is to describe comprehensively the various colloidal delivery systems, focusing mainly on their conventional and advanced methods of preparation, different characterization techniques and main success stories of their journey from bench to bedside of the patient. The review also touches the finer nuances of the use of modern formulation approach of DoE (Design of Experiments) in their formulation and the status of regulatory guidelines for the approval of these nanomedicines.

Cholesterol-induced physicochemical changes in dodecylamine-based metallosomes: drug entrapping ability and interactions with biological molecules

Multivesicular metallosomes have been synthesized from metal functionalized amphiphiles. They have been thoroughly characterized and explored for their entrapment efficiency towards drug and other biomolecules.

Optimization of Conditions for Cyanidin-3-OGlucoside (C3G) Nanoliposome Production by Response Surface Methodology and Cellular Uptake Studies in Caco-2 Cells

We aimed to optimize the formulation of C3G nanoliposomes using response surface methodology. Additionally, we evaluated the stability, particle change, and encapsulation efficiency (EE) of C3G nanoliposomes under different temperatures and storage durations, as well as in simulated gastrointestinal juice (SGF) and simulated intestinal fluid. The morphology of C3G nanoliposomes was observed by transmission electron microscope. The ability of C3G nanoliposomes to affect cancer cell morphology and inhibit cancer cell proliferation was studied with Caco-2 cells. Reverse-phase evaporation method is a simple and efficient method for liposome preparation. The optimal preparation conditions for this method were as follows: C3G concentration of 0.17 mg/mL, phosphatidylcholine/cholesterol ratio of 2.87, and rotary evaporation temperature of 41.41 °C. At optimal conditions, the particle size and EE of the C3G nanoliposomes were 165.78 ± 4.3 nm and 70.43% ± 1.95%, respectively. The C3G nanoliposomes showed an acceptable stability in SGF at 37 °C for 4 h, but were unstable under extended storage durations and high temperatures. Moreover, our results showed that different concentrations of C3G nanoliposomes affected the morphology and inhibited the proliferation of Caco-2 cells.

Aerosol Nanoencapsulation: Single-Pass Floating Self-Assembly of Biofunctional Hybrid Nanoplatforms

Multifunctional nanoplatforms were prepared via floating self-assembly using a hard nanoparticle (NP) as the core and a modified-polymer (MP, cholesterol-chitosan linked with polyethylenimine) droplet as the shell in a single-pass aerosol nanoencapsulation process. The floating hard NPs (silica, calcium carbonate, gold-decorated graphene oxide, and thiol-capped gold) were directly injected into MP droplets at the opening of a spraying device. Subsequently, the solvent was thermally extracted from the droplets, resulting in the formation of biofunctional nanoplatforms. Measured in vitro, the genes complexed with the nanoplatforms were transfected into target cells, exhibiting higher efficiencies for the MP particles alone without a significant increase in in vitro cell cytotoxicity. The aerosol encapsulation could be further extended to prepare other combinations [gold-silica and gold-calcium carbonate including doxorubicin (Dox)] using the MP, and their hybrid natures demonstrated photothermal cancer cell killing and chemo-thermal Dox release capabilities through surface plasmon resonance heating.

Quaternized Carboxymethyl Chitosan-Based Silver Nanoparticles Hybrid: Microwave-Assisted Synthesis, Characterization and Antibacterial Activity

A facile, efficient, and eco-friendly approach for the preparation of uniform silver nanoparticles (Ag NPs) was developed. The synthesis was conducted in an aqueous medium exposed to microwave irradiation for 8 min, using laboratory-prepared, water-soluble quaternized carboxymethyl chitosan (QCMC) as a chemical reducer and stabilizer and silver nitrate as the silver source. The structure of the prepared QCMC was characterized using Fourier transform infrared (FT-IR) and ¹H nuclear magnetic resonance (NMR). The formation, size distribution, and dispersion of the Ag NPs in the QCMC matrix were determined using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible (UV-Vis), transmission electron microscopy (TEM), and field emission scanning electron microscope (FESEM) analysis, and the thermal stability and antibacterial properties of the synthesized QCMC-based Ag NPs composite (QCMC-Ag) were also explored. The results revealed that (1) QCMC was successfully prepared by grafting quaternary ammonium groups onto carboxymethyl chitosan (CMC) chains under microwave irradiation in water for 90 min and this substitution appeared to have occurred at -NH₂ sites on C2 position of the pyranoid ring; (2) uniform and stable spherical Ag NPs could be synthesized when QCMC was used as the reducing and stabilizing agent; (3) Ag NPs were well dispersed in the QCMC matrix with a narrow size distribiution in the range of 17–31 nm without aggregation; and (4) due to the presence of Ag NPs, the thermal stability and antibacterial activity of QCMC-Ag were dramatically improved relative to QCMC.

Development of self-assembling peptide nanovesicle with bilayers for enhanced EGFR-targeted drug and gene delivery

Development of rational vectors for efficient drug and gene delivery is crucial for cancer treatment. In this study, epidermal growth factor receptor (EGFR)-binding peptide amphiphile (PA) were used as the primary bilayer skeleton material to construct ultra-stable self-assembling peptide nanovesicle (SPV). The resulted EGFR-targeted SPV (ESPV) could efficiently encapsulate therapeutic cargos (drugs or small interfering RNAs [siRNAs]) or labelled fluorescent cargo (quantum dots [QDs]) and exhibited excellent affinity for EGFR-positive cancer cells. Moreover, ESPV could deliver more drug or plasmid DNA to tumour sites and promote gene expression (a three-fold ratio of ESPVs vs cationic liposomes). Notably, the individual delivery or co-delivery of doxorubicin (DOX) and the acetylcholinesterase (AChE) gene via the ESPVs resulted in excellent drug/gene delivery both in vitro and in vivo and exerted a significant growth-suppressing effect on a liver cancer xenograft. This nanoscale, targeted cargo-packaging technology may provide a new strategy for the design of highly targeted cancer therapy vectors.

Codelivery of paclitaxel and small interfering RNA by octadecyl quaternized carboxymethyl chitosan-modified cationic liposome for combined cancer therapy

Conventional therapeutic approaches for cancer are limited by cancer cell resistance, which has impeded their clinical applications. The main goal of this work was to investigate the combined antitumor effect of paclitaxel with small interfering RNA modified by cationic liposome formed from modified octadecyl quaternized carboxymethyl chitosan. The cationic liposome was composed of 3β-[N-(N', N'-dimethylaminoethane)-carbamoyl]-cholesterol, dioleoylphosphatidylethanolamine, and octadecyl quaternized carboxymethyl chitosan. The cationic liposome properties were characterized by Fourier transform infrared spectroscopy, dynamic light scattering and zeta potential measurements, transmission electron microscopy, atomic force microscopy, and gel retardation assay. The cationic liposome exhibited good properties, such as a small particle size, a narrow particle size distribution, a good spherical shape, a smooth surface, and a good binding ability with small interfering RNA. Most importantly, when combined with paclitaxel and small interfering RNA, the composite cationic liposome induced a great enhancement in the antitumor activity, which showed a significantly higher in vitro cytotoxicity in Bcap-37 cells than liposomal paclitaxel or small interfering RNA alone. In conclusion, the results indicate that cationic liposome could be further developed as a codelivery system for chemotherapy drugs and therapeutic small interfering RNAs.

Brain-targeted delivery of trans-activating transcriptor-conjugated magnetic PLGA/lipid nanoparticles

Magnetic poly (D,L-lactide-co-glycolide) (PLGA)/lipid nanoparticles (MPLs) were fabricated from PLGA, L-α-phosphatidylethanolamine (DOPE), 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-amino (polyethylene glycol) (DSPE-PEG-NH₂), and magnetic nanoparticles (NPs), and then conjugated to trans-activating transcriptor (TAT) peptide. The TAT-MPLs were designed to target the brain by magnetic guidance and TAT conjugation. The drugs hesperidin (HES), naringin (NAR), and glutathione (GSH) were encapsulated in MPLs with drug loading capacity (>10%) and drug encapsulation efficiency (>90%). The therapeutic efficacy of the drug-loaded TAT-MPLs in bEnd.3 cells was compared with that of drug-loaded MPLs. The cells accumulated higher levels of TAT-MPLs than MPLs. In addition, the accumulation of QD-loaded fluorescein isothiocyanate (FITC)-labeled TAT-MPLs in bEnd.3 cells was dose and time dependent. Our results show that TAT-conjugated MPLs may function as an effective drug delivery system that crosses the blood brain barrier to the brain.

Assessment of drug entrapment within liposomes using photophysical probes

The photophysical and photochemical behavior of (R)-cinacalcet (CIN) and (S)-naproxen (NPX) entrapped within liposomes has been studied. For this purpose, liposome encapsulated drugs have been prepared through thin layer evaporation and characterized by transmission electron microscopy, cryoscopy scanning electron microscopy and dynamic light scattering. Steady state and time-resolved fluorescence experiments showed similar spectra, emission quantum yields, singlet energies and lifetimes for the selected drugs, outside and inside liposomes. By contrast, laser flash photolysis experiments revealed an important enhancement of the triplet lifetimes for entrapped drugs inside liposomes, indicating the spatial confinement existing in the microenvironment prevailing in these biomimetic entities. Thus, this photophysical property shows potential as a non-invasive, direct and valuable tool to monitor encapsulation of photoactive drugs and to probe the intraliposome environment. In addition, it provides a new quantitative indicator of the capability of liposomes to act as drug carriers.

Optimization on condition of epigallocatechin-3-gallate (EGCG) nanoliposomes by response surface methodology and cellular uptake studies in Caco-2 cells

The major component in green tea polyphenols, epigallocatechin-3-gallate (EGCG), has been demonstrated to prevent carcinogenesis. To improve the effectiveness of EGCG, liposomes were used as a carrier in this study. Reverse-phase evaporation method besides response surface methodology is a simple, rapid, and beneficial approach for liposome preparation and optimization. The optimal preparation conditions were as follows: phosphatidylcholine-to-cholesterol ratio of 4.00, EGCG concentration of 4.88 mg/mL, Tween 80 concentration of 1.08 mg/mL, and rotary evaporation temperature of 34.51°C. Under these conditions, the experimental encapsulation efficiency and size of EGCG nanoliposomes were 85.79% ± 1.65% and 180 nm ± 4 nm, which were close with the predicted value. The malondialdehyde value and the release test in vitro indicated that the prepared EGCG nanoliposomes were stable and suitable for more widespread application. Furthermore, compared with free EGCG, encapsulation of EGCG enhanced its inhibitory effect on tumor cell viability at higher concentrations.

Aerosol-based fabrication of modified chitosans and their application for gene transfection

Modified chitosan nanoparticles were conveniently obtained by a one-step aerosol method, and their potential for gene transfection was investigated. Droplets containing modified chitosans were formed by collison atomization, dried to form solid particles, and collected and studied for potential use as nanocarriers. Modified chitosans consisted of a chitosan backbone and an additional component [covalently attached cholesterol; or blends with poly(l-lysine) (PLL), polyethyleneimine (PEI), or poly(ethylene glycol) (PEG)]. Agarose gel retardation assays confirmed that modified chitosans could associate with plasmid DNA. Even though the average cell viability of cholesterol-chitosan (Ch-Cs) showed a slightly higher cytotoxicity (∼90% viability) than that for unmodified chitosan (Cs, ∼95%), transfection (>7.5 × 10(5) in relative light units (RLU) mg(-1)) was more effective than it was for Cs (∼7.6 × 10(4) RLU mg(-1)). The blending of PEI with Cs (i.e., a Cs/PEI) to produce transfection complexes enhanced the transfection efficiency (∼1.3 × 10(6) RLU mg(-1)) more than did the addition of PLL (i.e., a Cs/PLL, ∼9.3 × 10(5) RLU mg(-1)); however, it also resulted in higher cytotoxicity (∼86% viability for Cs/PEI vs ∼94% for Cs/PLL). The average cell viability (∼92%) and transfection efficiency (∼1.9 × 10(6) RLU mg(-1)) were complemented further by addition of PEG in Cs/PEI complexes (i.e., a Cs/PEI-PEG). This work concludes that gene transfection of Cs can be significantly enhanced by adding cationic polymers during aerosol fabrication without wet chemical modification processes of Cs.

MC540 and upconverting nanocrystal coloaded polymeric liposome for near-infrared light-triggered photodynamic therapy and cell fluorescent imaging

In clinic, the application of photodynamic therapy (PDT) in deep tissue is severely constrained by the limited penetration depth of visible light needed for activating the photosensitizer (PS). In this Article, a merocyanine 540 (MC540) and upconverting nanoparticle (UCN) coloaded functional polymeric liposome nanocarrier, (MC540 + UCN)/FPL, was designed and constructed successfully for solving this problem in PDT. Compared with the conventional approaches using UCNs absorbing PSs directly, the combination of UCN and polymeric liposome has unique advantages. The UCN core as a transducer can convert deep-penetrating near-infrared light to visible light for activating MC540. The functional polymeric liposome shell decorated with folate as a nanoshield can keep the UCN and MC540 stable, protect them from being attacked, and help them get into cells. The results show that (MC540 + UCN)/FPL is an individual nanosphere with an average size of 26 nm. MC540 can be activated to produce singlet oxygen successfully by upconverting fluorescence emitted from UCNs. After (MC540 + UCN)/FPL was modified with folate, the cell uptake efficiency increased obviously. More interestingly, in the PDT effect test, the (MC540 + UCN)/FPL nanocarrier further improved the inhibition effect on tumor cells by anchoring targeting folate and transactivating transduction peptide. Our data suggest that the (MC540 + UCN)/FPL nanocarrier may be a useful nanoplatform for future PDT treatment in deep-cancer therapy based on upconversion mechanism.

Amphiphilic chitosan derivatives-based liposomes: synthesis, development, and properties as a carrier for sustained release of salidroside

A novel amphiphilic chitosan derivative of N,N-dimethylhexadecyl carboxymethyl chitosan (DCMCs) was synthesized. The structure of DCMCs was confirmed via FT-IR and (1)H NMR, and the critical micelle concentration (CMC) was investigated by fluorescence spectroscopy. The results indicated that DCMCs has hydrophilic carboxyl and hydrophobic methylene groups and the CMC value was 23.00 mg·L(-1). The polymeric liposomes (DCMCs/cholesterol liposomes, DC-Ls) were developed, and its properties were evaluated. The DC-Ls exhibited multilamellar spheres with positive charge (+73.30 mV), narrow size distribution (PDI = 0.277), and good crystal properties. Salidroside was first to encapsulate into DC-Ls. Compared with traditional liposomes (phosphatidylcholine/cholesterol liposome, PC-Ls), DC-Ls showed higher encapsulation efficiency (82.46%) and slower sustained release rate. The in vitro salidroside release from DC-Ls was governed by two distinct stages (i.e., burst release and sustained release) and was dependent on the pH of the release medium. The case II transport and case I Fichian diffusion were the main release mechanisms for the entire release procedure. These results indicated that DC-Ls may be a potential carrier system for the production of functional foods that contain salidroside or other bioactive food ingredients.

Properties and evaluation of quaternized chitosan/lipid cation polymeric liposomes for cancer-targeted gene delivery

Development of high-stability and efficient nonviral vectors with low cytoxicity is important for targeted tumor gene therapy. In this study, cationic polymeric liposomes (CPLs), with similar lipid bilayer structure and high thermal stability, were prepared from polymeric surfactants of quaternized (carboxymethyl)chitosan with different carbon chains (dodecyl, tetradecyl, hexadecyl, and octadecyl). By comparing different factors that influence gene delivery, tetradecyl-quaternized (carboxymethy)chitosan (TQCMC) CPLs, with suitable size (184.4 ± 17.1 nm), ζ potentials (27.5 ± 4.9 mV), and productivity for synthesis TQCMC (weight yield 13.1%), were selected for gene transfection evaluation in various cancer cell lines. Although TQCMC CPLs have lower gene transfection efficiency compared with cationic liposomes (Lipofectamine 2000) in vitro, they displayed higher reporter gene delivery ability for cancer tissues (bearing U87 and SMMC-7721 tumors) in vivo after intravenous injection. TQCMC CPLs also have lower cell cytotoxicity and lower cytokine production or liver injury for BALB/c mice. We conclude that the CPLs are promising gene delivery systems that may be used to target various cancers.

Polymeric theranostics: using polymer-based systems for simultaneous imaging and therapy

Polymer-based nanomedicine is a large and fast growing field. Polymer-based systems have been extensively used as therapeutic carriers as well as bioimaging agents for example in tumour diagnosis. However, fewer polymeric systems have been able to combine both therapy and imaging in a new field that is called theranostics (theragnostics). This review aims to summarise the recent developments and trends on polymeric theranostics. Four different types of therapies/treatments are examined namely drug delivery, gene delivery, photodynamic therapy and hyperthermia treatment combined with different imaging moieties like magnetic resonance imaging agents, fluorescent agents and microbubbles for ultrasound imaging.

Smart multifunctional core-shell nanospheres with drug and gene co-loaded for enhancing the therapeutic effect in a rat intracranial tumor model

Glioblastoma with high mortality has been one of the most serious cancers threatening human health. Because of the present treatment limitations, there is an urgent need to construct a multifunctional vesicle for enhancing the treatment of in situ malignant glioblastoma. In our study, drug and gene co-loaded magnetic PLGA/multifunctional polymeric liposome (magnetic PLGA/MPLs) core-shell nanospheres were constructed. They were mainly self-assembled from two parts: hydrophobic PLGA cores that can load drugs and magnetic nanocrystals; and polymeric lipid shells anchored with functional molecules such as PEG chains, TAT peptides and RGD peptides that can help the vectors to condense the gene, prolong the circulation time, cross the blood brain barrier and target delivery to the cancer tissue. The results showed that the magnetic PLGA/MPLs nanosphere has a nanosized core-shell structure, can achieve sustained drug release and has good DNA binding abilities. Importantly, compared with the control group and other groups with single functionality, it can co-deliver the drug and gene into the same cell in vitro and show the strongest inhibiting effect on the growth of the in situ malignant glioblastoma in vivo. All of these results indicated that the different functional components of magnetic PLGA/MPLs, can form an organic whole and none of them can be dispensed with. The magnetic PLGA/MPLs nanosphere may be another option for treatment of glioblastoma.

Microstructural reorganization and cargo release in pyrene urethane methacrylate random copolymer hollow capsules

We report the synthesis of polymer microcapsules by direct one-pot free radical random copolymerization approach. Urethane methacrylate comb monomers having pendant pyrene (Py) and 3-pentadecyl phenol (PDP) units were copolymerized in a random manner using benzoyl peroxide (BPO) as free radical initiator in dimethylformamide (DMF) as solvent. These copolymers and corresponding homopolymers spontaneously self-organized into microspheres upon drop casting from solvents like DMF and tetrahydrofuran (THF). Stable microspheres were obtained in water by dialyzing THF solution of the polymers against water in dialysis bags with molecular weight cutoff of ∼2000. The hollow nature of the spheres was confirmed by rhodamine B (RhB) encapsulation followed by Förster resonance energy transfer (FRET) based fluorescence emission from RhB upon exciting pyrene. The microenvironment inside the capsule was probed by following the I(1)/I(3) ratio of pyrene emission as well as RhB release as a function of temperature. The RhB encapsulated in the pyrene homopolymer PIHP-100Py capsules experienced strong donor-acceptor interaction and did not undergo complete release even at high temperature (85 °C). The encapsulated RhB from the copolymers with low pyrene incorporation was released almost fully upon heating beyond 50 °C. Pyrene moieties in the PIHP-100Py were shielded from surrounding water and experienced a hydrophobic environment, whereas in the low pyrene incorporated copolymer the PDP units were better shielded from the hydrophilic environment. This work represents a simple approach to produce polymer hollow capsules, and the varying pyrene incorporation was used to trace the microenvironment inside the capsules.

Polymeric liposomes-coated superparamagnetic iron oxide nanoparticles as contrast agent for targeted magnetic resonance imaging of cancer cells

The purpose of this study was to use polymeric liposomes (PLs) with a targeting ligand (folate) to coat superparamagnetic iron oxide nanoparticles (SPIONs) and transfer the magnetic nanoparticles from organic phases to aqueous solutions, and further evaluate their efficacy as a magnetic resonance imaging (MRI) contrast agent. The formed nanoparticles exhibited a narrow range of size dispersity (core size of the particles is about 8-10 nm) and relatively high T2 relaxivities (r2 = 164.14 s(-1) mM(-1) for folate-PLs-coated SPIONs). The in vitro tumor cell targeting efficacy of the folate functionalized and PLs-coated SPIONs was evaluated upon observing cellular uptake of magnetite liposomes by HeLa cells, which overexpresses surface receptors for folic acid. In the Prussian blue staining experiments, cells incubated with folate-PLs-coated SPIONs showed much higher intracellular iron density than did the cells incubated with the folate-free PLs-coated SPIONs. Meanwhile, the MTT assay explains the negligible cell cytotoxicity of SPIONs and folate-PLs-coated SPIONs. In HeLa cells, the in vitro MRI study also indicates the better T2-weighted images in folate-PLs-coated SPIONs than in folate-free PLs-coated SPIONs.