Radiation synthesis and characterization of sodium alginate/chitosan/hydroxyapatite nanocomposite hydrogels: a drug delivery system for liver cancer

Polysaccharide Hydroxyapatite (Nano)composites and Their Biomedical Applications: An Overview of Recent Years

Hydroxyapatite can combine with polysaccharide originating biomaterials with special applications in the biomedical field. In this review, the synthesis of (nano)composites is discussed, focusing on natural polysaccharides such as alginate, chitosan, and pectin. In this way, advances in recent years in the development of preparing materials are revised and discussed. Therefore, an overview of the recent synthesis and applications of polyssacharides@hydroxyapatites is presented. Several studies based on chitosan@hydroxyapatite combined with other inorganic matrices are highlighted, while pectin@hydroxyapatite is present in a smaller number of reports. Biomedical applications as drug carriers, adsorbents, and bone implants are discussed, combining their dependence with the nature of interactions on the molecular scale and the type of polysaccharides used, which is a relevant aspect to be explored.

A green approach for preparation of chitosan/hydroxyapatite/graphitic carbon nitride hydrogel nanocomposite for improved 5-FU delivery

Reducing the side effects of cancer treatment methods is an important issue. The loading efficiency and sustained release of 5-Fluorouracil (5-FU) have been significantly improved by creating a new method. A nanocarrier with pH sensitivity has been developed through the w/o/w emulsification method. It is loaded with 5-FU and comprises of chitosan (CS), hydroxyapatite (HAp), and graphitic carbon nitride (g-C3N4). g-C3N4 nanosheets were incorporated in CS/HAp hydrogel to improve the entrapment and loading efficiency. Drug loading efficiency and entrapment efficiency reached 48 % and 87 %, respectively, and the FTIR and XRD tests verified evidence of the formation of chemical bonds among the drug and nanocarrier. Structural analysis was done using FE-SEM. DLS and zeta potential were employed to obtain average size distribution and surface charge. The release profile of 5-FU in various conditions shows the nanoparticles' pH dependence, and the nanocomposite's controlled release is consistent with the Korsmeyer-Peppas kinetic model. Cell apoptosis and cytotoxicity were evaluated in vitro using flow cytometry and MTT analysis. The biocompatibility of CS/HAp/g-C3N4 against MCF-7 cells was shown by the MTT method and confirmed by flow cytometry. CS/HAp/g-C3N4@5-FU led to the highest apoptosis rate in MCF-7 cells, indicating the nanocarrier's efficiency in killing cancer cells. These data indicate that the designed CS/HAp/g-C3N4@5-FU can be a potential drug for treating cancer cells.

Synthesis, Characterization, and Investigation of Doxorubicin Drug Release Properties of Poly(acrylamide-co-acrylic Acid/Maleic Acid)-Hydroxyapatite Composite Hydrogel

BACKGROUND

Hydroxyapatite and its derivatives have been used for a lot of applications. One of them is drug release studies. Due to its low adhesion strength and lack of the strength and durability required for load-carrying applications, there is a need to improve the properties of hydroxyapatite. For this aim, the most important factors are increasing pH sensitivity and preventing coagulation. Mixing it with multifunctional polymers is the best solution.

OBJECTIVES

The main objectives are: 1- preparing poly(acrylamide-co-acrylic acid/maleic acid)- hydroxyapatite (PAm-co-PAA/PMA-HApt), 2- assessment of (PAm-co-PAA/PMA-HApt) and dox-loaded poly(acrylamide-co-acrylic acid/maleic acid) (Dox-(PAm-co-PAA/PMA-HApt)) composite hydrogels, and 3- elucidating the difference in behavior of drug release studies between hydroxyapatite (HApt) and poly(acrylamide-co-acrylic acid/maleic acid) composite hydrogels.

METHODS

A composite of PAm-co-PAA/PMA-HApt was prepared by direct polymerization of acrylamide-co-acrylic acid/maleic acid in a suspension of HApt. The drug loading and release features of PAm-co-PAA/PMA-HApt and HApt were then investigated for doxorubicin (dox) release. Using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TG/DTA), this unique composite hydrogel has been physicochemically investigated. Also, a colorimetric assay was used to assess the in vitro biocompatible support and anticancer activity of HApt and the newly developed composite hydrogel XTT (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide) assay.

RESULTS

According to the results of drug release studies of this new material, it is pH sensitive, and PAm-co-PAA/PMA-HApt demonstrated a faster release than HApt at 37°C in the acidic solution of pH 4.5 than in the neutral solution of pH 7.4. The XTT assay outcomes also demonstrated the biocompatibility of PAm-co-PAA/PMA-HApt and HApt and the cytotoxic effect of dox-loaded PAm-co-PAA/PMA-HApt.

CONCLUSION

It should be inferred that the drug release profile was improved at pH 4.5 by the newly produced pH-sensitive composite hydrogel.

Nanocomposite Hydrogels-A Promising Approach towards Enhanced Bioavailability and Controlled Drug Delivery

Nanotechnology has emerged as the eminent focus of today's research to overcome challenges related to conventional drug delivery systems. A wide spectrum of novel delivery systems has been investigated to improve the therapeutic outcomes of drugs. The polymer-based nanocomposite hydrogels (NCHs) that have evolved as efficient carriers for controlled drug delivery are of particular interest in this regard. Nanocomposites amalgamate the properties of both nanoparticles (NPs) as well as hydrogels, exhibiting superior functionalities over conventional hydrogels. This multiple functionality is based upon advanced mechanical, electrical, optical as well as magnetic properties. Here is a brief overview of the various types of nanocomposites, such as NCHs based on Carbon-bearing nanomaterials, polymeric nanoparticles, inorganic nanoparticles, and metal and metal-oxide NPs. Accordingly, this article will review numerous ways of preparing these NCHs with particular emphasis on the vast biomedical applications displayed by them in numerous fields such as tissue engineering, drug delivery, wound healing, bioprinting, biosensing, imaging and gene silencing, cancer therapy, antibacterial therapy, etc. Moreover, various features can be tuned, based on the final application, by controlling the chemical composition of hydrogel network, which may also influence the released conduct. Subsequently, the recent work and future prospects of this newly emerging class of drug delivery system have been enlisted.

Development and Evaluation of Cellulose Derivative and Pectin Based Swellable pH Responsive Hydrogel Network for Controlled Delivery of Cytarabine

In the present study, pH-sensitive, biodegradable, and biocompatible Na-CMC/pectin poly(methacrylic acid) hydrogels were synthesized using an aqueous free radical polymerization technique and encapsulated by cytarabine (anti-cancer drug). The aim of the project was to sustain the plasma profile of cytarabine through oral administration. Sodium carboxymethyl cellulose (Na-CMC) and pectin were cross-linked chemically with methacrylic acid (MAA) as a monomer, using methylene bisacrylamide (MBA) as cross-linker and ammonium per sulfate (APS) as an initiator. Prepared hydrogel formulations were characterized for their texture, morphology, cytarabine loading efficiency, compositional and structural properties, thermal nature, stability, swelling response, drug release profile (pH 1.2 and pH 7.4), and in-vivo pharmacokinetic evaluation. Cytarabine-loaded hydrogels were also evaluated for their safety profile by carrying out toxicity studies in rabbits. Results demonstrated efficient encapsulation of cytarabine into the prepared network with loading ranging from 48.5-82.3%. The highest swelling ratio of 39.38 and maximum drug release of 83.29-85.27% were observed at pH 7.4, highlighting the pH responsiveness of the grafted system. Furthermore, cytarabine maximum release was noticed over 24 h, ensuring a sustained release response for all formulations. Histopathological studies and hemolytic profiles confirmed that the prepared hydrogel system was safe, biocompatible, and non-irritant, showing no symptoms of any toxicities and degeneration in organs. Moreover, pharmacokinetic estimation of the cytarabine-loaded hydrogel showed a remarkable increase in the plasma half-life from 4.44 h to 9.24 h and AUC from 22.06 μg/mL.h to 56.94 μg/mL.h. This study revealed that the prepared hydrogel carrier system has excellent abilities in delivering the therapeutic moieties in a controlled manner.

Biocompatible, Multi-Mode, Fluorescent, T2 MRI Contrast Magnetoelectric-Silica Nanoparticles (MagSiNs), for On-Demand Doxorubicin Delivery to Metastatic Cancer Cells

There is a need to improve current cancer treatment regimens to reduce systemic toxicity, to positively impact the quality-of-life post-treatment. We hypothesized the negation of off-target toxicity of anthracyclines (e.g., Doxorubicin) by delivering Doxorubicin on magneto-electric silica nanoparticles (Dox-MagSiNs) to cancer cells. Dox-MagSiNs were completely biocompatible with all cell types and are therapeutically inert till the release of Doxorubicin from the MagSiNs at the cancer cells location. The MagSiNs themselves are comprised of biocompatible components with a magnetostrictive cobalt ferrite core (4−6 nm) surrounded by a piezoelectric fused silica shell of 1.5 nm to 2 nm thickness. The MagSiNs possess T2-MRI contrast properties on par with RESOVIST™ due to their cobalt ferrite core. Additionally, the silica shell surrounding the core was volume loaded with green or red fluorophores to fluorescently track the MagSiNs in vitro. This makes the MagSiNs a suitable candidate for trackable, drug nanocarriers. We used metastatic triple-negative breast cancer cells (MDAMB231), ovarian cancer cells (A2780), and prostate cancer cells (PC3) as our model cancer cell lines. Human umbilical vein endothelial cells (HUVEC) were used as control cell lines to represent blood-vessel cells that suffer from the systemic toxicity of Doxorubicin. In the presence of an external magnetic field that is 300× times lower than an MRI field, we successfully nanoporated the cancer cells, then triggered the release of 500 nM of doxorubicin from Dox-MagSiNs to successfully kill >50% PC3, >50% A2780 cells, and killed 125% more MDAMB231 cells than free Dox.HCl. In control HUVECs, the Dox-MagSiNs did not nanoporate into the HUVECS and did not exhibited any cytotoxicity at all when there was no triggered release of Dox.HCl. Currently, the major advantages of our approach are, (i) the MagSiNs are biocompatible in vitro and in vivo; (ii) the label-free nanoporation of Dox-MagSiNs into cancer cells and not the model blood vessel cell line; (iii) the complete cancellation of the cytotoxicity of Doxorubicin in the Dox-MagSiNs form; (iv) the clinical impact of such a nanocarrier will be that it will be possible to increase the current upper limit for cumulative-dosages of anthracyclines through multiple dosing, which in turn will improve the anti-cancer efficacy of anthracyclines.

Role of Polysaccharides Mimetic Components in Targeted Cancer Treatment

Organic or inorganic compounds are synthesized or formulated in a manner that they completely show their therapeutic actions like as a natural polysaccharide in the body. Polysaccharides, the major type of natural polymers, are efficiently biologically active, non-toxic, hydrophilic, and biodegradable and show various properties. In this manuscript, the main focus is on delivering anticancer drugs with the help of mimetic components of polysaccharides. All data collected for this manuscript was from PubMed, Elsevier, Taylor, and Francis Bentham science journals. Most chemotherapeutics are therapeutically toxin to the human body, have a narrow therapeutic index, sluggish pharmaceutical delivery mechanisms, and are poorly soluble in water. The use of mimetic components of polysaccharides leads to the enhancement of the solubility of drugs in the biological environment. The manuscript summarizes the use of mimetic components of polysaccharides along with anticancer agents which are capable to inhibit the growth of cancerous cells in the body which shows lesser adverse effects in the biological system compared to other therapies.

Synthesis and Characterization of Carboxymethyl Chitosan Nanosponges with Cyclodextrin Blends for Drug Solubility Improvement

This study aimed to enhance the solubility and release characteristics of docetaxel by synthesizing highly porous and stimuli responsive nanosponges, a nano-version of hydrogels with the additional qualities of both hydrogels and nano-systems. Nanosponges were prepared by the free radical polymerization technique and characterized by their solubilization efficiency, swelling studies, sol-gel studies, percentage entrapment efficiency, drug loading, FTIR, PXRD, TGA, DSC, SEM, zeta sizer and in vitro dissolution studies. In vivo toxicity study was conducted to assess the safety of the oral administration of prepared nanosponges. FTIR, TGA and DSC studies confirmed the successful grafting of components into the stable nano-polymeric network. A porous and sponge-like structure was visualized through SEM images. The particle size of the optimized formulation was observed in the range of 195 ± 3 nm. The fabricated nanosponges noticeably enhanced the drug loading and solubilization efficiency of docetaxel in aqueous media. The drug release of fabricated nanosponges was significantly higher at pH 6.8 as compared to pH 1.2 and 4.5. An acute oral toxicity study endorsed the safety of the system. Due to an efficient preparation technique, as well as its enhanced solubility, excellent physicochemical properties, improved dissolution and non-toxic nature, nanosponges could be an efficient and a promising approach for the oral delivery of poorly soluble drugs.

Alginic Acid Polymer-Hydroxyapatite Composites for Bone Tissue Engineering

Natural bone is a composite organic-inorganic material, containing hydroxyapatite (HAP) as an inorganic phase. In this review, applications of natural alginic acid (ALGH) polymer for the fabrication of composites containing HAP are described. ALGH is used as a biocompatible structure directing, capping and dispersing agent for the synthesis of HAP. Many advanced techniques for the fabrication of ALGH-HAP composites are attributed to the ability of ALGH to promote biomineralization. Gel-forming and film-forming properties of ALGH are key factors for the development of colloidal manufacturing techniques. Electrochemical fabrication techniques are based on strong ALGH adsorption on HAP, pH-dependent charge and solubility of ALGH. Functional properties of advanced composite ALGH-HAP films and coatings, scaffolds, biocements, gels and beads are described. The composites are loaded with other functional materials, such as antimicrobial agents, drugs, proteins and enzymes. Moreover, the composites provided a platform for their loading with cells for the fabrication of composites with enhanced properties for various biomedical applications. This review summarizes manufacturing strategies, mechanisms and outlines future trends in the development of functional biocomposites.

Anticancer Effect of Alginate-Chitosan Hydrogel Loaded with Curcumin and Chrysin on Lung and Breast Cancer Cell Lines

OBJECTIVE

We conducted the present study to investigate the anticancer effects of curcumin and chrysin loaded in the alginate-chitosan hydrogel on breast cancer (T47D) and lung cancer (A549).

BACKGROUND

Cancer, which is defined as abnormal cell growth, is one of the biggest public health problems in the world. Natural compounds, such as polyphenols, are used as chemo-preventive and chemotherapeutic agents in different types of cancer owing to their antioxidant, antineoplastic, and cytotoxic properties. To improve their bioavailability and releasing behavior, hydrogel systems with high drug loading and stability and hydrophilic nature have been designed.

METHODS

The curcumin-chrysin-loaded alginate-chitosan hydrogels were prepared through the ionic gelation mechanism utilizing CaCl2. The prepared hydrogels were studied by using the Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The MTT and DAPI staining assays were employed for cytotoxicity and apoptosis studies of curcumin-chrysin-loaded alginate-chitosan hydrogels. The effects of the curcumin-chrysin-loaded alginate-chitosan hydrogels on the cell cycle of cell lines T47D and A549 were also evaluated using the propidium iodide staining.

RESULTS

The FTIR indicated specific bands at 1607 and 1422 cm-1 (the carbonyl of alginate) at 834 cm-1 (sodium alginate), 1447 cm-1, and 1026 cm-1 (COOH and C-O stretching bands alginate and chitosan). The curcumin-chrysin-loaded alginate-chitosan hydrogels could significantly (p<0.05) reduce the viability and induce apoptosis, Morover, cause G2/M arrest of the cell cycle in both A549 and T47D cell lines.

CONCLUSION

The alginate-chitosan hydrogels could work best as an enhanced anticancer drug delivery system.

Formulation and evaluation of interpenetrating polymeric network for controlled drug delivery

Novel Cytarabine-loaded agarose and fenugreek-based hydrogel were formulated via the crosslinking process. Graft copolymerization of methacrylic acid (MAA) on agarose and fenugreek was carried out by using methylene bisacrylamide (MBA) as a crosslinker and potassium persulfate as an initiator. The influence of different formulation ingredients (fenugreek, agarose, MBA, MAA) on swelling index, percentage drug release, and percentage gel content were investigated. It was observed that an increase in the concentration of fenugreek and agarose resulted in an increase in the swelling index (72.45-97.17%). However, an increase in the amount of MBA led to a decrease in the swelling index from 74.23% to 57.74%. A similar result tendency was noted in the case of drug release. FTIR was employed to elucidate effective grafting. The thermal behavior of hydrogel was evaluated through TGA and DSC analysis whereas surface morphology was elucidated through SEM. Release studies were performed at both acidic and basic pH, that is, 1.2 and 7.4. Hence, formulated biocompatible hydrogels proved to be a promising system for the controlled delivery of Cytarabine.

Peptide-Chitosan Engineered Scaffolds for Biomedical Applications

Peptides are signaling epitopes that control many vital biological events. Increased specificity, synthetic feasibility with concomitant lack of toxicity, and immunogenicity make this emerging class of biomolecules suitable for different applications including therapeutics, diagnostics, and biomedical engineering. Further, chitosan, a naturally occurring linear polymer composed of d-glucosamine and N-acetyl-d-glucosamine units, possesses anti-microbial, muco-adhesive, and hemostatic properties along with excellent biocompatibility. As a result, chitosan finds application in drug/gene delivery, tissue engineering, and bioimaging. Despite these applications, chitosan demonstrates limited cell adhesion and lacks biosignaling. Therefore, peptide-chitosan hybrids have emerged as a new class of biomaterial with improved biosignaling properties and cell adhesion properties. As a result, recent studies encompass increased application of peptide-chitosan hybrids as composites or conjugates in drug delivery, cell therapy, and tissue engineering and as anti-microbial material. This review discusses the recent investigations involving chitosan-peptide materials and uncovers various aspects of these interesting hybrid materials for biomedical applications.

Methionine-Functionalized Graphene Oxide/Sodium Alginate Bio-Polymer Nanocomposite Hydrogel Beads: Synthesis, Isotherm and Kinetic Studies for an Adsorptive Removal of Fluoroquinolone Antibiotics

In spite of the growing demand for new antibiotics, in the recent years, the occurrence of fluoroquinolone antibiotics (as a curative agent for urinary tract disorders and respiratory problems) in wastewater have drawn immense attention. Traces of antibiotic left-overs are present in the water system, causing noxious impact on human health and ecological environments, being a global concern. Our present work aims at tackling the major challenge of toxicity caused by antibiotics. This study deals with the efficient adsorption of two commonly used fluoroquinolone (FQ) antibiotics, i.e., Ofloxacin (OFX) and Moxifloxacin (MOX) on spherical hydrogel beads generated from methionine‒functionalized graphene oxide/ sodium alginate polymer (abbreviated Met-GO/SA) from aqueous solutions. The composition, morphology and crystal phase of prepared adsorbents were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR), high-resolution transmission electron microscopy (HR-TEM) and thermogravimetric analysis/differential thermogravimetry (TGA/DTG). Batch adsorption tests are followed to optimize the conditions required for adsorption process. Both functionalized and non-functionalized adsorbents were compared to understand the influence of several experimental parameters, such as, the solution pH, contact time, adsorbent dosage, temperature and initial concentration of OFX and MOX on adsorption. The obtained results indicated that the functionalized adsorbent (Met-GO/SA) showed a better adsorption efficiency when compared to non-functionalized (GO/SA) adsorbent. Further, the Langmuir isotherm was validated as the best fitting model to describe adsorption equilibrium and pseudo second-order-kinetic model fitted well for both types of adsorbate. The maximum adsorption capacities of Met-GO/SA were 4.11 mg/g for MOX and 3.43 mg/g for OFX. Thermodynamic parameters, i.e., ∆G°, ∆H° and ∆S° were also calculated. It was shown that the overall adsorption process was thermodynamically favorable, spontaneous and exothermic in nature. The adsorbents were successfully regenerated up to four cycles with 0.005 M NaCl solutions. Overall, our work showed that the novel Met-GO/SA nanocomposite could better contribute to the removal of MOX and OFX from the liquid media. The gel beads prepared have adequate features, such as simple handling, eco-friendliness and easy recovery. Hence, polymer gel beads are promising candidates as adsorbents for large-scale water remediation.

Porous and highly responsive cross-linked β-cyclodextrin based nanomatrices for improvement in drug dissolution and absorption

AIMS

Aim of the study was to enhance the solubility of Chlorthalidone by developing beta-cyclodextrin cross-linked hydrophilic nanomatrices.

MAIN METHODS

Nine different formulations were fabricated by free radical polymerization technique. All formulations were characterized through different studies. FTIR spectroscopy of unloaded and loaded nanomatrices was processed to determine compatibility of constituents and that of the drug with the system. Surface morphology of the nanomatrices was studied by SEM. The size of the optimized formulation was determined by zeta sizer. Swelling, in-vitro release and solubility studies were carried out in different media and results of in-vitro release profiles of nanomatrices and commercially available tablet of Chlorthalidone were compared. For determination of biocompatibility, toxicity studies were proclaimed in rabbits.

KEY FINDINGS

Main peaks of corresponding functional groups of individual constituents and that of drug were depicted in FTIR spectra of unloaded and loaded nanomatrices. Porous and fluffy structure was visualized through SEM images. Particle size of the optimized formulation was in the range of 175 ± 5.27 nm. Percent loading of optimized formulation showed the best result. Comparing the in-vitro drug release profiles of nanomatrices and commercially available tablet, the results of the synthesized nanomatrices were quite satisfactory. Solubility profiles were also high as compared to the drug alone. Moreover, toxicity studies confirmed that nanomatrices were biocompatible and no sign of any toxic effect was found.

SIGNIFICANCE

We concluded that our developed nanomatrices had successfully enhanced the solubility of Chlorthalidone and can also be used for other poorly aqueous soluble drugs.

Polymerization Reactions and Modifications of Polymers by Ionizing Radiation

Ionizing radiation has become the most effective way to modify natural and synthetic polymers through crosslinking, degradation, and graft polymerization. This review will include an in-depth analysis of radiation chemistry mechanisms and the kinetics of the radiation-induced C-centered free radical, anion, and cation polymerization, and grafting. It also presents sections on radiation modifications of synthetic and natural polymers. For decades, low linear energy transfer (LLET) ionizing radiation, such as gamma rays, X-rays, and up to 10 MeV electron beams, has been the primary tool to produce many products through polymerization reactions. Photons and electrons interaction with polymers display various mechanisms. While the interactions of gamma ray and X-ray photons are mainly through the photoelectric effect, Compton scattering, and pair-production, the interactions of the high-energy electrons take place through coulombic interactions. Despite the type of radiation used on materials, photons or high energy electrons, in both cases ions and electrons are produced. The interactions between electrons and monomers takes place within less than a nanosecond. Depending on the dose rate (dose is defined as the absorbed radiation energy per unit mass), the kinetic chain length of the propagation can be controlled, hence allowing for some control over the degree of polymerization. When polymers are submitted to high-energy radiation in the bulk, contrasting behaviors are observed with a dominant effect of cross-linking or chain scission, depending on the chemical nature and physical characteristics of the material. Polymers in solution are subject to indirect effects resulting from the radiolysis of the medium. Likewise, for radiation-induced polymerization, depending on the dose rate, the free radicals generated on polymer chains can undergo various reactions, such as inter/intramolecular combination or inter/intramolecular disproportionation, b-scission. These reactions lead to structural or functional polymer modifications. In the presence of oxygen, playing on irradiation dose-rates, one can favor crosslinking reactions or promotes degradations through oxidations. The competition between the crosslinking reactions of C-centered free radicals and their reactions with oxygen is described through fundamental mechanism formalisms. The fundamentals of polymerization reactions are herein presented to meet industrial needs for various polymer materials produced or degraded by irradiation. Notably, the medical and industrial applications of polymers are endless and thus it is vital to investigate the effects of sterilization dose and dose rate on various polymers and copolymers with different molecular structures and morphologies. The presence or absence of various functional groups, degree of crystallinity, irradiation temperature, etc. all greatly affect the radiation chemistry of the irradiated polymers. Over the past decade, grafting new chemical functionalities on solid polymers by radiation-induced polymerization (also called RIG for Radiation-Induced Grafting) has been widely exploited to develop innovative materials in coherence with actual societal expectations. These novel materials respond not only to health emergencies but also to carbon-free energy needs (e.g., hydrogen fuel cells, piezoelectricity, etc.) and environmental concerns with the development of numerous specific adsorbents of chemical hazards and pollutants. The modification of polymers through RIG is durable as it covalently bonds the functional monomers. As radiation penetration depths can be varied, this technique can be used to modify polymer surface or bulk. The many parameters influencing RIG that control the yield of the grafting process are discussed in this review. These include monomer reactivity, irradiation dose, solvent, presence of inhibitor of homopolymerization, grafting temperature, etc. Today, the general knowledge of RIG can be applied to any solid polymer and may predict, to some extent, the grafting location. A special focus is on how ionizing radiation sources (ion and electron beams, UVs) may be chosen or mixed to combine both solid polymer nanostructuration and RIG. LLET ionizing radiation has also been extensively used to synthesize hydrogel and nanogel for drug delivery systems and other advanced applications. In particular, nanogels can either be produced by radiation-induced polymerization and simultaneous crosslinking of hydrophilic monomers in "nanocompartments", i.e., within the aqueous phase of inverse micelles, or by intramolecular crosslinking of suitable water-soluble polymers. The radiolytically produced oxidizing species from water, •OH radicals, can easily abstract H-atoms from the backbone of the dissolved polymers (or can add to the unsaturated bonds) leading to the formation of C-centered radicals. These C-centered free radicals can undergo two main competitive reactions; intramolecular and intermolecular crosslinking. When produced by electron beam irradiation, higher temperatures, dose rates within the pulse, and pulse repetition rates favour intramolecular crosslinking over intermolecular crosslinking, thus enabling a better control of particle size and size distribution. For other water-soluble biopolymers such as polysaccharides, proteins, DNA and RNA, the abstraction of H atoms or the addition to the unsaturation by •OH can lead to the direct scission of the backbone, double, or single strand breaks of these polymers.

A Statistical Study on the Development of Metronidazole-Chitosan-Alginate Nanocomposite Formulation Using the Full Factorial Design

The goal of this study was to develop and statistically optimize the metronidazole (MET), chitosan (CS) and alginate (Alg) nanoparticles (NP) nanocomposites (MET-CS-AlgNPs) using a (2¹ × 3¹ × 2¹) × 3 = 36 full factorial design (FFD) to investigate the effect of chitosan and alginate polymer concentrations and calcium chloride (CaCl₂) concentration ondrug loading efficiency(LE), particle size and zeta potential. The concentration of CS, Alg and CaCl₂ were taken as independent variables, while drug loading, particle size and zeta potential were taken as dependent variables. The study showed that the loading efficiency and particle size depend on the CS, Alg and CaCl₂ concentrations, whereas zeta potential depends only on the Alg and CaCl₂ concentrations. The MET-CS-AlgNPs nanocomposites were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), scanning electron microscopy (SEM) and in vitro drug release studies. XRD datashowed that the crystalline properties of MET changed to an amorphous-like pattern when the nanocomposites were formed.The XRD pattern of MET-CS-AlgNPs showed reflections at 2θ = 14.2° and 22.1°, indicating that the formation of the nanocompositesprepared at the optimum conditions havea mean diameter of (165±20) nm, with a MET loading of (46.0 ± 2.1)% and a zeta potential of (−9.2 ± 0.5) mV.The FTIR data of MET-CS-AlgNPs showed some bands of MET, such as 3283, 1585 and 1413 cm⁻¹, confirming the presence of the drug in the MET-CS-AlgNPs nanocomposites. The TGA for the optimized sample of MET-CS-AlgNPs showed a 70.2% weight loss compared to 55.3% for CS-AlgNPs, and the difference is due to the incorporation of MET in the CS-AlgNPs for the formation of MET-CS-AlgNPs nanocomposites. The release of MET from the nanocomposite showed sustained-release properties, indicating the presence of an interaction between MET and the polymer. The nanocomposite shows a smooth surface and spherical shape. The release profile of MET from its MET-CS-AlgNPs nanocomposites was found to be governed by the second kinetic model (R² between 0.956–0.990) with more than 90% release during the first 50 h, which suggests that the release of the MET drug can be extended or prolonged via the nanocomposite formulation.

Capecitabine-loaded anti-cancer nanocomposite hydrogel drug delivery systems: in vitro and in vivo efficacy against the 4T1 murine breast cancer cells

In this work, nanocomposite hydrogel drug delivery systems based on polyvinyl alcohol and montmorillonite loaded with the capecitabine, as an anti-cancer drug, were developed for oral administration. The gel fraction and swelling ability of the prepared nanocomposite hydrogels were experimentally measured. In vitro release kinetics of capecitabine in nanocomposite hydrogel drug delivery systems were studied. In vitro flow cytometry assay was utilized to exhibit the anti-cancer activity of the prepared nanocomposite hydrogel drug delivery systems against 4T1 cancer cell line. The anti-tumor efficacy of the nanocomposite hydrogel drug delivery systems was also studied in vivo on animal models. The results showed that the amount of montmorillonite incorporated into the nanocomposite hydrogel drug delivery systems could be recognized as a key parameter to adjust the values of the gel fraction, swelling and capecitabine release rate in a manner which by increasing the montmorillonite content, the gel fraction is increased while the swelling and drug release rate are decreased. The flow cytometry results demonstrated the better anti-cancer activity of the capecitabine-loaded nanocomposite hydrogel drug delivery systems as compared with the pure capecitabine. The in vivo assays indicated that the administration of nanocomposite hydrogel drug delivery systems had a significant effect on the reduction of the tumor growth in animal models as compared with pure capecitabine administration. In general, the prepared nanocomposite hydrogel drug delivery systems exhibited a suitable efficacy against 4T1 cancer cell line both in vitro and in vivo and they could be considered as promising candidates for controlled release of anti-cancer drugs in chemotherapy with enhanced therapeutic effects.

Polymers and Polymer Nanocomposites for Cancer Therapy

Synthetic polymers, biopolymers, and their nanocomposites are being studied, and some of them are already used in different medical areas. Among the synthetic ones that can be mentioned are polyolefins, fluorinated polymers, polyesters, silicones, and others. Biopolymers such as polysaccharides (chitosan, hyaluronic acid, starch, cellulose, alginates) and proteins (silk, fibroin) have also become widely used and investigated for applications in medicine. Besides synthetic polymers and biopolymers, their nanocomposites, which are hybrids formed by a macromolecular matrix and a nanofiller (mineral or organic), have attracted great attention in the last decades in medicine and in other fields due to their outstanding properties. This review covers studies done recently using the polymers, biopolymers, nanocomposites, polymer micelles, nanomicelles, polymer hydrogels, nanogels, polymersomes, and liposomes used in medicine as drugs or drug carriers for cancer therapy and underlines their responses to internal and external stimuli able to make them more active and efficient. They are able to replace conventional cancer drug carriers, with better results.

Analysis of In Vitro Osteoblast Culture on Scaffolds for Future Bone Regeneration Purposes in Dentistry

One of the main focuses of tissue engineering is to search for tridimensional scaffold materials, complying with nature's properties for tissue regeneration. Determining material biocompatibility is a fundamental step in considering its use. Therefore, the purpose of this study was to analyze osteoblast cell adhesion and viability on different materials to determine which was more compatible for future bone regeneration. Tridimensional structures were fabricated with hydroxyapatite, collagen, and porous silica. The bovine bone was used as material control. Biocompatibility was determined by seeding primary osteoblasts on each tridimensional structure. Cellular morphology was assessed by SEM and viability through confocal microscopy. Osteoblast colonization was observed on all evaluated materials' surface, revealing they did not elicit osteoblast cytotoxicity. Analyses of four different materials studied with diverse compositions and characteristics showed that adhesiveness was best seen for HA and viability for collagen. In general, the results of this investigation suggest these materials can be used in combination, as scaffolds intended for bone regeneration in dental and medical fields.

A Novel Complex of Chitosan⁻Sodium Carbonate and Its Properties

Chitosan has excellent properties, as it is nontoxic, mucoadhesive, biocompatible, and biodegradable. However, the poor water solubility of chitosan is a major disadvantage. Here, a novel chitosan-sodium carbonate complex was formed by adding a large amount of sodium carbonate to a chitosan/acetic acid solution, which is water-soluble. Fourier transform infrared spectroscopy, energy dispersive spectrometry, scanning electron microscopy, and solid-state nuclear magnetic resonance techniques were used to detect and characterize the aforementioned complex, which appeared to be a neat flake crystal. Solid-state nuclear magnetic resonance (SSNMR) was used to verify the connections between carbonate, sodium ions, and the protonated amino group in chitosan on the basis of 13C signals at the chemical shift of 167.745 ppm and 164.743 ppm. Further confirmation was provided by the strong cross-polarization signals identified by the SSNMR 2D 13C⁻¹H frequency-switched Lee⁻Goldberg heteronuclear correlation spectrum. The cytotoxicity of a film prepared using this complex was tested using rat fibroblasts. The results show that the film promoted cell proliferation, which provides evidence to support its nontoxicity. The ease of film-forming and the results of cytocompatibility testing suggest that the chitosan-sodium carbonate complex has the potential for use in tissue engineering.

Study on the preparation and drug release property of soybean selenoprotein/carboxymethyl chitosan composite hydrogel

Soybean selenoprotein/carboxymethyl chitosan (SSP/CMCS) composite hydrogel obtained by the crosslinking of genipin was evaluated for caffeine release. The gelation process of the hydrogel was investigated by resonance Rayleigh scattering spectra and viscosity methods. The hydrogels presented a compact network structure, which was observed by positive fluorescence microscopy (PFM). The structural properties of the hydrogel were revealed by fluorescence and FT-IR. The swelling characteristic of the hydrogel and its application in the slow release of caffeine were also studied. These results indicate that there is obvious interaction between SSP and CMCS by the addition of genipin, and the CMCS/SSP solution experiences a significant sol-gel phase transition process upon polymerization. The swelling ratio and release of caffeine slow down obviously at pH 1.2. However, larger swelling and more drug release can be observed at pH 7.4. The experimental values of the empiric diffusional exponent show that the release profiles abide by the non-Fickian diffusion process under both investigated pH conditions. The hydrogel, which is pale transparent with light yellow color at room temperature, can be formulated to be a suitable carrier for site-specific drug delivery.

Chitosan nanocomposites based on distinct inorganic fillers for biomedical applications

Chitosan (CHI), a biocompatible and biodegradable polysaccharide with the ability to provide a non-protein matrix for tissue growth, is considered to be an ideal material in the biomedical field. However, the lack of good mechanical properties limits its applications. In order to overcome this drawback, CHI has been combined with different polymers and fillers, leading to a variety of chitosan-based nanocomposites. The extensive research on CHI nanocomposites as well as their main biomedical applications are reviewed in this paper. An overview of the different fillers and assembly techniques available to produce CHI nanocomposites is presented. Finally, the properties of such nanocomposites are discussed with particular focus on bone regeneration, drug delivery, wound healing and biosensing applications.

The impact of functionalized CNT in the network of sodium alginate-based nanocomposite beads on the removal of Co(II) ions from aqueous solutions

Significant efforts have been made to develop highly efficient adsorbents to remove radioactive Co(II) ion pollutants from medical and industrial wastewaters. In this study, amide group functionalized multi-walled carbon nanotube (CNT-CONH2) imprinted in the network of sodium alginate containing hydroxyapatite, and new nanocomposite beads were synthesized. Then, they were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). The prepared nanocomposite beads were used as an adsorbent of Co(II) ions from an aqueous solution. The presence and distribution of Co(II) ions in the surface of the nanocomposite beads was confirmed using FESEM, EDS and metal mapping analysis. The effect of various experimental conditions such as time, pH, and initial concentration of the adsorbate solution and temperature on the adsorption capacity of the nanocomposite beads were explored. The maximum Co(II) ions adsorption capacity of the prepared nanocomposite beads with the largest surface area of 163.4m(2)g(-1) was 347.8mgg(-1) in the optimized condition. The adsorption mechanism followed a pseudo-second-order kinetic model. Furthermore, the Freundlich appears to produce better fit than the Langmuir adsorption isotherm. Finally, thermodynamic studies suggest that endothermic adsorption process of Co(II) ions is spontaneous and thermodynamically favorable.