Drug Encapsulation Capacity Research Articles

PH-responsive chitosan-mediated spherical mesoporous silica microspheres for high loading and controlled delivery of 5-Fluorouracil

The objective of this study is to develop a drug carrier to overcome the inherent drawbacks of 5-Fluorouracil (5-Fu), including low bioavailability, short half-life, and systemic toxicity. In the present work, mesoporous silica nanoparticles (MSNs) capped by chitosan (CS) to encapsulate 5-Fu (5-Fu MSNs/CS) were fabricated by the sol-gel process, ultrasonic impregnation, and emulsion cross-linking. The 5-Fu MSNs/CS microspheres exhibit pH-responsive drug release and remarkable drug encapsulation capacity, as well as perfect sphericity, high specific surface area (680.62 cm2/g), and uniform particle size (2.64 ± 0.05 μm). The drug-loading content and encapsulation efficiency are 14.12 ± 0.53 % and 82.21 ± 2.13 %, respectively. The cumulative release of 5-Fu from MSNs/CS microspheres is fast and sustained at pH 5.0 (89.56 ± 0.97 %) compared to that at pH 7.4 (57.88 ± 0.91 %) in 96 h, and it is Fickian diffusion controlled. In conclusion, the MSNs/CS microspheres prepared in this study could be potential carriers for 5-Fu delivery.

Hydrogen-bonded cytosine-endowed supramolecular polymeric nanogels: Highly efficient cancer cell targeting and enhanced therapeutic efficacy

We demonstrate that cytosine moieties within physically cross-linked supramolecular polymers not only manipulate drug delivery and release, but also confer specific targeting of cancer cells to effectively enhance the safety and efficacy of chemotherapy—and thus hold significant potential as a new perspective for development of drug delivery systems. Herein, we successfully developed physically cross-linked supramolecular polymers (PECH-PEG-Cy) comprised of hydrogen-bonding cytosine pendant groups, hydrophilic poly(ethylene glycol) side chains, and a hydrophobic poly(epichlorohydrin) main chain. The polymers spontaneously self-assemble into a reversibly hydrogen-bonded network structure induced by cytosine and directly form spherical nanogels in aqueous solution. Nanogels with a high hydrogen-bond network density (i.e., a higher content of cytosine moieties) exhibit outstanding long-term structural stability in cell culture substrates containing serum, whereas nanogels with a relatively low hydrogen-bond network density cannot preserve their structural integrity. The nanogels also exhibit numerous unique physicochemical characteristics in aqueous solution, such as a desirable spherical size, high biocompatibility with normal and cancer cells, excellent drug encapsulation capacity, and controlled pH-responsive drug release properties. More importantly, in vitro experiments conclusively indicate the drug-loaded PECH-PEG-Cy nanogels can selectively induce cancer cell-specific apoptosis and cell death via cytosine receptor-mediated endocytosis, without significantly harming normal cells. In contrast, control drug-loaded PECH-PEG nanogels, which lack cytosine moieties in their structure, can only induce cell death in cancer cells through non-specific pathways, which significantly inhibits the induction of apoptosis. This work clearly demonstrates that the cytosine moieties in PECH-PEG-Cy nanogels confer selective affinity for the surface of cancer cells, which enhances their targeted cellular uptake, cytotoxicity, and subsequent induction of programmed cell death in cancer cells.

Nanogel: Types, Methods of Preparation, Limitation, Evaluation and Application – A Systematic Review

Nanogels combine the characteristics of nanomaterials with hydrogels. To meet the expanding demands from various areas, a sizable number of nanogels have been designed and manufactured using the emulsion solvent diffusion nano precipitated method, emulsion evaporation of the solvent method, reverse micellar method and modified diffusion emulsification method. Thermosensitive nanogel, pH-sensitive nanogel, ultrasound-sensitive magnetic response, response to multiple stimuli, chain transfer polymerization, photo-induced crosslinking polymerization and modifications for active targeting are the types of nanogels based on response towards stimuli and polysaccharide, chitosan, pullulan, hyaluronic acid, alginate, cyclodextrin, gum acacia, protein are used to prepare nanogel. Nanogels have considerable potential and novelty within the biomedical sector due to their uniformity, adjustable dimensions, little toxicity, resilience in the presence of serum, and capacity for responsive behavior with a comparatively high drug encapsulation capacity. Nanogels have considerable potential in bioactive substance delivery, organ targeting, and chemotherapy. The article highlighted the preparation, types, evaluation and applicability of nanogel as a targeted delivery system.

Ethosomes as Promising Transdermal Delivery Systems of Natural‐Derived Active Compounds

Ethosomes are novel lipid‐based vesicular systems that demonstrate unique improvements in drug delivery with respect to other nanoparticles, especially for transdermal applications. Their high ethanol content strongly improves flexibility and deformability, which allows squeezing through the intercellular spaces without any drug leakage. The ethanol, moreover, contributes to increase the fluidity of the lipids of the cell membranes in dermal layers, allowing an in‐depth penetration of the nanostructures. Moreover, the high ethanol content of ethosomes allows the promotion of the encapsulation of either hydrophilic or lipophilic active agents, a feature particularly useful when it deals with natural extracts, a family of compounds characterized by a huge chemical variability. As a further advantage, being natural extracts often obtained in ethanol‐based solutions, their incorporation in ethosomes makes not necessarily expensive and time‐consuming procedures finalized at solvent removal. Following the initial exploitation of ethosomes, research focuses on the development of variants such as invasomes and transethosomes, which show improved drug encapsulation and delivery capacity. This review provides the state‐of‐the‐art on ethosomal research, with special attention on the encapsulation and delivery of natural extracts and their transdermal delivery.

Bioorthogonal chemical imaging of solid lipid nanoparticles with minimal labeling by stimulated Raman scattering microscopy

AbstractSolid lipid nanoparticles (SLNs) are a state‐of‐the‐art lipid‐based pharmaceutical drug delivery system. Advantages of SLNs include high biocompatibility, low immunogenicity, superiority in drug encapsulation capacity, and improved colloidal stability. They became widely known in late 2020, as several COVID‐19 vaccines are built upon SLNs technology. Despite the increasing impact, the characterization methods of SLNs are currently very limited especially in biological environment, which hinders fundamental understanding of the delivery mechanism and contributes to relatively low success rate in clinical translations. Here, we present close‐to‐label‐free imaging of deuterated SLNs using the emerging stimulated Raman scattering (SRS) microscopy. The introduction of deuterium to lipid structure renders bioorthogonal chemical specificity. Notably, with this approach, we have achieved ultrahigh single‐particle sensitivity both in vitro and in vivo, even with particle counting ability. Our bioorthogonal chemical imaging modality by SRS microscopy can be generalized to visualize a wide spectrum of lipid‐based drug carriers with high spatiotemporal resolution, chemical specificity, and ultimate sensitivity. This work opens up ways to address critical questions in SLN drug delivery and could also facilitate innovations in lipid nanotechnology and clinical translations.Key points Direct imaging of lipid nanocarrier that is the basis of the COVID‐19 vaccines. Novel single‐particle imaging technique applied to nanomedicine. Frontier of nanomaterial, optical imaging, and molecular pharmacology.

Influence of Polycaprolactone Concentration and Solvent Type on the Dimensions and Morphology of Electrosprayed Particles.

Polycaprolactone (PCL) micro- and nanoparticles produced using the electrospraying technique present high drug encapsulation capacity, a controllable surface area, and a good cost-benefit ratio. PCL is also considered a non-toxic polymeric material with excellent biocompatibility and biodegradability. All these characteristics make PCL micro- and nanoparticles a promising material for tissue engineering regeneration, drug delivery, and surface modification in dentistry. In this study, PCL electrosprayed specimens were produced and analyzed to determine their morphology and size. Three PCL concentrations (2, 4, and 6 wt%) and three solvent types (chloroform (CF), dimethylformamide (DMF), and acetic acid (AA)) with various solvent mixtures ratios (1:1 CF/DMF, 3:1 CF/DMF, 100% CF, 1:1 AA/CF, 3:1 AA/CF, and 100% AA) were used while keeping the remaining electrospray parameters constant. SEM images followed by ImageJ analysis showed a change in the morphology and size of the particles among various tested groups. A two-way ANOVA demonstrated a statistically significant interaction (p < 0.001) between PCL concentration and solvents on the size of the particles. With the increase in the PCL concentration, an increase in the number of fibers was observed among all the groups. The morphology and dimensions of the electrosprayed particles, as well as the presence of fibers, were significantly dependent on the PCL concentration, choice of solvent, and solvent ratio.

Combined and Single Doxorubicin/Naproxen Drug Loading and Dual-Responsive pH/Ultrasound Release from Flexible Metal-Organic Framework Nanocarriers

In this study, the flexible aluminum-based MIL-53(Al) metal-organic framework was loaded with doxorubicin (DOX) and naproxen (NAP) and was examined as a promising pH/ultrasound dual-responsive drug delivery system. The two drugs were encapsulated in MIL-53(Al) individually to produce the DOX@MIL-53(Al) and NAP@MIL-53(Al) nanocarriers. They were also encapsulated as a dual-drug formulation to produce the DOX* + NAP*@MIL-53(Al) nanocarrier. The MOF nanoparticles were characterized using the Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), and Dynamic Light Scattering (DLS) techniques. In the case of the DOX@MIL, the nanocarriers’ drug Encapsulation Efficiency (EE) and Encapsulation Capacity (EC) were 92% and 16 wt.%, respectively, whereas, in the case of NAP@MIL-53(Al), the average NAP EE and EC were around 97.7% and 8.5 wt.%, respectively. On the other hand, in the DOX* + NAP*@MIL-53(Al) nanoparticles, the average DOX* EE and EC were 38.9% and 6.22 wt.%, respectively, while for NAP*, the average EE and EC were 70.2% and 4.49 wt.%, respectively. In vitro release experiments demonstrated the good pH and Ultrasound (US) dual-responsiveness of these nanocarriers, with a maximum US-triggered DOX and NAP release, at a pH level of 7.4, of approximately 53% and 95%, respectively. In comparison, the measured release was around 90% and 36% at pH 5.3 for DOX and NAP, respectively. In the case of the dualdrug formulation, the nanocarrier displayed similar pH/US dual-responsive behavior. Finally, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) results confirmed the biocompatibility and low cytotoxicity of MIL-53(Al) at concentrations up to 1000 μg/ml.

Biocompatible magnetic hydroxyapatite Fe3O4-HAp nanocomposites for T1-magnetic resonance imaging guided photothermal therapy of breast cancer

Theranostic nanomedicine designs integrating diagnostic and therapeutic paradigms have been achieving considerable success at clinics. However, the toxicity of nanocomposites in these designs remains a major obstacle to the success of personalized medicine. Herein, highly biocompatible iron and hydroxyapatite materials were selected to design a Fe3O4-HAp nano-theranostic system with controlled dimensions using simple solvothermal synthesis. The biocompatibility of Fe3O4-HAp magnetic hydroxyapatite nanocomposites (MHNCs) was further enhanced by Food and Drug Administration- (FDA-) approved triblock copolymers, namely, Pluronic® F-127. Indeed, polymer modification improved the drug encapsulation capacity of HAp, and 70% anti-TROP 2 was loaded onto the surface of MHNCs for intracellular targeting of breast cancer. The Fe3O4 component of MHNCs possessed a high T1-MR imaging enhancement feature with an excellent r1 value, demonstrating these MHNCs as capable substitutes for Gd-based toxic contrast agents. Moreover, indocyanine green (ICG-) coupled-MHNCs revealed strong absorption in the near-infrared region and produced enough temperature (75 °C), even at low (50 ug/mL) concentrations, to ablate cancerous cells upon 808 laser irradiation to induce cell toxicity and apoptosis. The promising diagnostic and photothermal therapeutic performance of these designed MHNCs make them an ideal nano-theranostic agent.

Review on nanogel/emulgel formulations of traditional medicines

Nanotechnology is being ventured into as an emerging trend eliciting improvements in nearly all technological fields, and the pharmaceutical sector is no exception to this. It has been used for many years for synthetic drugs. But nowadays, the focus is on traditional medicines. This work is focused on the nanogel and nanoemulgel formulations of traditional medication and holds strong relevance in the emerging era of nanomedicine. Herbal medicines are making a resurgence in the twenty-first century, as the dangers and limitations of modern medicine become increasingly evident, and herbal remedies are considered a balanced and reasonable approach to treatment. Advances in analysis and clinical research demonstrate the efficacy of herbal drugs in disease prevention and treatment. The main issue with herbal remedies is their inability to dissolve and stabilize. New technical breakthroughs have the potential to eliminate the problems connected with herbal therapy.Nanoformulations reflect the interface between new technology and herboceuticals. Thus nanosized novel drug delivery system of herbal drugs has a potential future due to their high drug encapsulation capacity, homogeneity, low toxicity, and improved stability.

The Advancing of Selenium Nanoparticles Against Infectious Diseases.

Infectious diseases, caused by the direct exposure of cellular or acellular pathogens, are found to be closely associated with multiple inflammation and immune responses, keeping one of the top threats to human health. As an indispensable trace element, Selenium (Se) plays important roles in antioxidant defence and redox state regulation along with a variety of specific metabolic pathways. In recent decades, with the development of novel nanotechnology, Selenium nanoparticles (Se NPs) emerged as a promising agent for biomedical uses due to their low toxicity, degradability and high bioavailability. Taking the advantages of the strong ability to trigger apoptosis or autophagy by regulating reactive oxygen species (ROS), Se NPs have been widely used for direct anticancer treatments and pathogen killing/clearance in host cells. With excellent stability and drug encapsulation capacity, Se NPs are now serving as a kind of powerful nano-carriers for anti-cancer, anti-inflammation and anti-infection treatments. Notably, Se NPs are also found to play critical roles in immunity regulations, such as macrophage and T effector cell activation, which thus provides new possibilities to achieve novel nano-immune synergetic strategy for anti-cancer and anti-infection therapies. In this review, we summarized the progress of preparation methods for Se NPs, followed by the advances of their biological functions and mechanisms for biomedical uses, especially in the field of anti-infection treatments. Moreover, we further provide some prospects of Se NPs in anti-infectious diseases, which would be helpful for facilitating their future research progress for anti-infection therapy.

Understanding the pH dependent fluorescence and doxorubicin release from graphene oxide functionalized citric acid dendrimer as a highly efficient drug delivery system

In this work, the third generation of a dendrimer based on citric acid and 1, 3, 5 benzene tricarbonyl trichloride, as a core (G3), was synthesized to modify graphene oxide (GO) surface. A novel graphene oxide hybrid (GO-G3) with green fluorescent in an acidic medium (pH 4) was developed to track its interaction with cancer and healthy cell lines as a potential drug carrier. GO-G3 is highly fluorescent due to hydrogen bonding that passivates the electron-hole recombination process. The interaction among G3 dendrimer and GO surface was investigated at two pH in detail as the main cause for observation of such pH-dependent fluorescent in acidic media. The functionalized GO were studied carefully and characterized by multiple techniques such as fluorescence spectroscopy; SEM (scanning electron microscope); TEM (Transmission electron microscopy), FT-IR (Fourier transformed infrared spectroscopy); XRD (X-ray diffraction spectroscopy); XPS (X-ray photoelectron spectroscopy), DLS (Dynamic light scattering), AFM (atomic force microscopy); UV-Vis absorption spectroscopy, Raman spectroscopy and CLSM (Confocal laser scanning microscopy). The synthesized dendrimer displayed no emission under a UV lamp. However, after the functionalization of the GO surface with G3 dendrimer, green photoluminescence was detected at 471 nm. G3 dendrimer covers GO surface and prevents both GO sheets restacking and also electron-hole recombination process that consequently led to the observation of pH-dependent photoluminescence (PL). The drug encapsulation capacity of hybrid for doxorubicin (DOX) drug was 159.48% and also, the drug release profile of GO-G3/DOX hybrid indicated a pH-dependent release with more preference for drug discharge in acidic media. Furthermore, the cytotoxicity investigation of GO-G3/DOX against T47D cells (human breast cancer cells) indicated the IC50 value of 12.02 μg/ml.

Nanogels: An overview of properties, biomedical applications, future research trends and developments

Nanogels in biomedical field are promising and innovative materials as dispersions of hydrogel nanoparticles based on crosslinked polymeric networks that have been called as next generation drug delivery systems due to their relatively high drug encapsulation capacity, uniformity, tunable size, ease of preparation, minimal toxicity, stability in the presence of serum, and stimuli responsiveness. Nanogels show a great potential in chemotherapy, diagnosis, organ targeting and delivery of bioactive substances. The main subjects reviewed in this article concentrates on: (i) Nanogel assimilation in the nanomedicine domain; (ii) Features and advantages of nanogels, the main characteristics, such as: swelling capacity, stimuli sensitivity, the great surface area, functionalization, bioconjugation and encapsulation of bioactive substances, which are taken into account in designing the structures according to the application; some data on the advantages and limitations of the preparation techniques; (iii) Recent progress in nanogels as a carrier of genetic material, protein and vaccine. Recent tremendous developments in their synthesis open access to systems with complex architectures and compositions allowing for tailoring microgels with specific properties. At the same time state-of-the-art theoretical and simulation approaches offer deeper understanding of the behavior and structure of nano- and microgels under external influences and confinement at interfaces or at high volume fractions. Developments in the experimental analysis of nano- and microgels have become particularly important for structural investigations covering a broad range of length scales relevant to the internal structure, the overall size and shape, and interparticle interactions in concentrated samples. Here we summarize emerging research of nanogewls for biomedical applications and provide an overview of the state-of-the-art, recent developments as well as emerging trends in the field of nano- and microgels.

Study effect of Baicalein encapsulated/loaded Chitosan-nanoparticle on allergic Asthma pathology in mouse model.

Asthma as chronic airway disease has high prevalence in children and imbalance of Th1/Th2 is a critical mechanism in pathogenesis of the asthma. Baicalein as a cell protective and anti-inflammatory flavonoid may have anti-asthma effect. Therefore, for better using lung, baicalein was used in chitosan-nanoparticle as anti-asthma treatment. Baicalein was loaded and encapsulated in chitosan nanoparticle. The morphology, physical characters (particle size, zeta potential and FT-IR) were analyzed. Drug encapsulation and loading capacity, accumulative release-time were studied. After asthma model producing, the mice were treated with L-B-NP and E-B-NP. At least, MCh challenge test, Cytokines measurement and Lung Histopathology were done. Nanoparticles had average size 285±25nm with negative charge -2.5mV. The L-B-NP decreased penh value and E-B-NP decreased inflammation. Both nanoparticles increased IL-12 and decreased IL-5. Also, L-B-NP decreased mucus secretion in bronchi. L-B-NP and E-B-NP control immune-allergo-inflammatory response of asthma. L-B-NP controlled AHR and E-B-NP controlled inflammation that can be used as controlling anti-asthma drug.

Judging Enzyme-Responsive Micelles by Their Covers: Direct Comparison of Dendritic Amphiphiles with Different Hydrophilic Blocks.

Enzymatically degradable polymeric micelles have great potential as drug delivery systems, allowing the selective release of their active cargo at the site of disease. Furthermore, enzymatic degradation of the polymeric nanocarriers facilitates clearance of the delivery system after it has completed its task. While extensive research is dedicated toward the design and study of the enzymatically degradable hydrophobic block, there is limited understanding on how the hydrophilic shell of the micelle can affect the properties of such enzymatically degradable micelles. In this work, we report a systematic head-to-head comparison of well-defined polymeric micelles with different polymeric shells and two types of enzymatically degradable hydrophobic cores. To carry out this direct comparison, we developed a highly modular approach for preparing clickable, spectrally active enzyme-responsive dendrons with adjustable degree of hydrophobicity. The dendrons were linked with three different widely used hydrophilic polymers—poly(ethylene glycol), poly(2-ethyl-2-oxazoline), and poly(acrylic acid) using the CuAAC click reaction. The high modularity and molecular precision of the synthetic methodology enabled us to easily prepare well-defined amphiphiles that differ either in their hydrophilic block composition or in their hydrophobic dendron. The micelles of the different amphiphiles were thoroughly characterized and their sizes, critical micelle concentrations, drug loading, stability, and cell internalization were compared. We found that the micelle diameter was almost solely dependent on the hydrophobicity of the dendritic hydrophobic block, whereas the enzymatic degradation rate was strongly dependent on the composition of both blocks. Drug encapsulation capacity was very sensitive to the type of the hydrophilic block, indicating that, in addition to the hydrophobic core, the micellar shell also has a significant role in drug encapsulation. Incubation of the spectrally active micelles in the presence of cells showed that the hydrophilic shell significantly affects the micellar stability, localization, cell internalization kinetics, and the cargo release mechanism. Overall, the high molecular precision and the ability of these amphiphiles to report their disassembly, even in complex biological media, allowed us to directly compare the different types of micelles, providing striking insights into how the composition of the micelle shells and cores can affect their properties and potential to serve as nanocarriers.

Herbal Nanogel Formulation: A Novel Approch

:Increasing research interest has been focused on controlled as well as sustained drug delivery using natural and biocompatible constituents in recent years. Many of them herbal constituents are avoided due to pharmacokinetic and pharmacodynamic issues of herbal constituents. There are many new technological ways and comparisons have been studied to upgrade the herbal discoveries in pharmaceutical market. This review will focus on the nanogel for herbal medicines with high delivery rate, patient compliance and efficiency. A nanoparticles contained hydrogel with cross linked polymer networks called as ‘Nanogel’. Nanogel preferred for herbal medicines due to stability and for the ease. Nanogels in terms of herbal drugs are promising and novel approach which also can be called as future generation drug delivery systems owing to high drug encapsulation capacity, uniformity, minimum toxicity, greater stability.

Serum protein-hyaluronic acid complex nanocarriers: Structural characterisation and encapsulation possibilities

A protein-polysaccharide-based potential nanocarrier system have been developed via a simple, one-step preparation protocol without the use of long-term heating and the utilization of hardly removable crosslinking agents, surfactants, and toxic organic solvents. To the best of our knowledge, this article is the first which summarizes in detail the pH-dependent quantitative relationship between the bovine serum albumin (BSA) and hyaluronic acid (HyA) confirmed by several physico-chemical techniques. The formation of colloidal complex nanoconjugates with average diameter of ca. 210–240 nm is strongly depend on the pH and the applied BSA:HyA mass ratio. Particle charge titrations studies strongly support the core-shell type structure, where the BSA core is covered by a thick HyA shell. Besides the optimization of these conditions, the drug encapsulation capacity and the dissolution profiles have been also studied for ibuprofen (IBU) and 2-picolinic acid (2-PA) as model drugs.

In situ scavenging of mitochondrial ROS by anti-oxidative MitoQ/hyaluronic acid nanoparticles for environment-induced dry eye disease therapy

Excessive accumulation of mitochondrial reactive oxygen species (ROS) triggers the vicious circle in development of environment-induced dry eye disease (DED). Thus, mitochondria-specific antioxidants that in situ scavenge ROS and restore homeostasis in mitochondria can be employed to inhibit or alleviate environment-induced DED. Herein, novel mitochondria-specific anti-oxidative nanoparticles (NPs) consisting of negatively charged hyaluronic acid and the positively charged MitoQ were prepared by charge-driven self-assembly strategy assisted by heat treatment. The effects of operation temperature on size, morphology, zeta potential, and polydispersity index (PDI) of the MitoQ NPs were investigated. The NPs prepared by this strategy exhibited relatively higher drug encapsulation capacity and loading efficiency compared to that prepared from amphiphilic block copolymer using the traditional self-assembly method. The heat treatment enhanced the interaction between the charged molecules HA and MitoQ, thus the resultant NPs had more compact structure with uniform spherical morphology. In comparison with free MitoQ, MitoQ NPs had increased mitochondrial distribution, thereby exhibited a stronger mitochondrial ROS scavenging activity in the tested cell line. MitoQ NPs also exerted a better curative effect against environment-induced DED: it better alleviated the DED symptoms, reduced the ROS accumulation on eye surface, and enhanced the suppression of gene expression of inflammation related-factors in vivo. These results present the potential use of MitoQ NPs, for the treatment of a wide range of ROS-related diseases.

Superparamagnetic chitosan nanocomplexes for colorectal tumor-targeted delivery of irinotecan.

Conventional chemotherapy is effective for metastatic tumors widely present in colorectal cancer patients; however, chemotherapy may cause severe systemic toxicity due to a lack of specificity towards cancer cells. Effective delivery systems that can enhance targeted drug delivery to the desired tumor site and simultaneously protect the activity of drugs are in high demand. To that end, this study developed chitosan-based polyelectrolyte complexes (PECs) with the orientation of superparamagnetic nanoparticles, which enables the targeting delivery of the first-line model drug irinotecan (IRT) to the tumor area under a magnetic field. Colloidal PECs were mildly and facilely fabricated with chitosan and poly(glutamic acid) (PGA) via an all-in-water process, excluding the use of any potentially toxic chemicals. Iso-dispersed superparamagnetic Fe3O4 nanoparticles with relatively small particle diameters (~10nm) were embedded into the IRT-loaded nano-PECs. The optimized nano-PECs showed high drug encapsulation capacity and improved anti-colon cancer cell efficacy compared with the free drug. Furthermore, the magnetic nano-PECs exhibited effective internalization by colon tumor cells, and favorable tumor-targeting ability was demonstrated via in vivo biodistribution study. Therefore, this magnetic targeted drug delivery nano-PECs system provides a promising platform to overcome the side effects of conventional chemotherapy for colorectal cancer.

Architecture based selectivity of Amphiphilic block copolymers of poly(ethylene oxide) and poly(ε-caprolactone) for drug delivery

Architecture of amphiphilic block copolymers is an important parameter that affects their critical micelles concentration (CMC), drug loading capacity and drug release behavior. In this context, 4-arm star-shaped block copolymers comprising of poly(ethylene oxide) as a hydrophilic segment and poly(ε-caprolactone) as a hydrophobic part, 4 s-P(CL-b-EO), is compared with its linear counterpart having otherwise similar total molar mass, chemical composition and molar mass of individual components (PCL-b-PEO-b-PCL). As a first step, the micelles prepared by linear block copolymer (LPM) and star-shaped block copolymer (SPM) were compared for CMC, drug encapsulation capacity, and drug release behavior. Micelles based on star-shaped polymers were found to have low CMC, high drug encapsulation capacity and better sustained release behavior. Blood hemolysis and cytotoxicity studies of both linear and star-shaped block copolymers revealed that these are safer to use for biological applications. Micelles based on star shaped polymers (SPM) and linear block copolymer (LPM) were further employed for individual delivery of cefixime (CEF) and its co-delivery with clarithromycin (CLA). Finally, growth inhibition efficiency of SPM, LPM, CEF, CLA, CEF-SPM, CEF-LPM, CEF-CLA-SPM, and CEF-CLA-LPM are evaluated against S. pneumoniae and S. pneumoniae (resistant) by antibacterial assay and morphological topography imaging by AFM. Minimum inhibitory concentration (MIC50) of drugs encapsulated in SPM is found to be considerably lower compared to direct application of drugs and drug encapsulated in LPM.

Purification of Boron Nitride Nanotubes Enhances Biological Application Properties.

Commercially available boron nitride nanotubes (BNNTs) and their purified form (pBNNTs) were dispersed in aqueous solutions with various dispersants, and their cytotoxicity and drug encapsulation capacity were monitored. Our data suggest that pBNNTs showed an average increase in dispersibility of 37.3% in aqueous solution in the presence of 10 different dispersants. In addition, 100 μg of pBNNTs induced an average decrease in cytotoxicity of 27.4% compared to same amount of BNNTs in normal cell lines. The same amount of pBNNTs can encapsulate 10.4-fold more drug (camptothecin) compared to BNNTs. These data suggest that the purification of BNNTs improves several of their properties, which can be applied to biological experiments and are thus essential in the biological application of BNNTs.