Release dynamics of ciprofloxacin from swellable nanocarriers of poly(2-hydroxyethyl methacrylate): an in vitro study

Injectable and 3D Extrusion Printable Hydrophilic Silicone-Based Hydrogels for Controlled Ocular Delivery of Ophthalmic Drugs

While silicone elastomers have found widespread use in the biomedical industry, 3D printing them has proven to be difficult due to the material's slow drying time, low viscosity, and hydrophobicity. Herein, we arrested the hydrophilic silicone (HS) macrochains into a semi-interpenetrating polymer network (semi-IPN) via an in situ photogelation-assisted 3D microextrusion printing technique. The flow behavior of the pregel solutions and the mechanical properties of the printed HS hydrogels were tested, showing a high elastic modulus (approximately 15 kPa), a low tan δ, high elasticity, and delayed network rupturing. The uniaxial compression tests demonstrated a nearly negligible permanent deformation, suggesting that the printed hybrid hydrogel maintained its elastic properties. Drug loading and diffusion in the microporous hydrogel are shown via the non-Fickian anomalous transport mechanism, leading to highly tunable loading/releasing profiles (approximately 20% cumulative release) depending on the HS concentration. The drug encapsulation exhibits exceptional stability, remaining intact without any degradation even after a storage period of 1 month. As far as we know, this is the first soft biomaterial based on HS that functions as an exceptional controlled drug delivery device.

Development and characterization of Polycaprolactone/chitosan-based scaffolds for tissue engineering of various organs: A review

Research in creating 3D structures mirroring the extracellular matrix (ECM) with accurate environmental cues holds paramount significance in biological applications.Biomaterials that replicate ECM properties-mechanical, physicochemical, and biological-emerge as pivotal tools in mimicking ECM behavior.Incorporating synthetic and natural biomaterials is widely used to produce scaffolds suitable for the intended organs.Polycaprolactone (PCL), a synthetic biomaterial, boasts commendable mechanical properties, albeit with relatively modest biological attributes due to its hydrophobic nature.Chitosan (CTS) exhibits strong biological traits but lacks mechanical resilience for complex tissue regeneration.Notably, both PCL and CTS have demonstrated their application in tissue engineering for diverse types of tissues.Their combination across varying PCL:CTS ratios has increased the likelihood of fabricating scaffolds to address defects in sturdy and pliable tissues.This comprehensive analysis aspires to accentuate their distinct attributes within tissue engineering across different organs.The central focus resides in the role of PCL:CTS-based scaffolds, elucidating their contribution to the evolution of advanced functional 3D frameworks tailored for tissue engineering across diverse organs.Moreover, this discourse delves into the considerations pertinent to each organ.

Effect of pectin and attapulgite filler on swelling, network parameters and controlled release of diltiazem hydrochloride from polyacrylic copolymer gel

Pectin grafted polyacrylic copolymer hydrogels were made by free radical crosslink copolymerization of acrylic acid (AA) and acrylamide (AM) in an aqueous solution of pectin. N'N-methylene bis acrylamide (MBA) was used as a crosslinker. During the polymerization reaction the attapulgite (APG) filler was also incorporated in situ into the network of the copolymer gel. Several filled hydrogels were prepared by varying the amount of pectin and APG filler. These hydrogels were characterized by FTIR, ¹³C NMR, XRD, TGA, SEM, mechanical properties, DMA, swelling, diffusion characteristics and network parameters. The release kinetics of a model drug diltiazem hydrochloride (DT) was studied with these hydrogels. The wt% of pectin, APG and MBA was optimized with a central composite design (CCD) model of response surface methodology (RSM) with equilibrium swelling ratio (ESR), drug adsorption (mg/100 mg gel) and drug release% in 16 h as response. Accordingly, the hydrogel prepared with 5:1 AA:AM molar ratio, 25 wt% monomer concentration, 1% each of initiator and MBA concentration, 18 wt% pectin and 2 wt% APG showed an optimized ESR of 17.75, drug loading of 27.58 and a drug release % of 92.5 in 16 h at a solution pH of 7.4.

Design and Characterization of Biomimetic Kerateine Aerogel-Electrospun Polycaprolactone Scaffolds for Retinal Cell Culture

Age-related macular degeneration (AMD) is a retinal disease that affects 196 million people and causes nearly 9% of blindness worldwide. While several pharmacological approaches slow the effects of AMD, in our opinion, cell-based strategies offer the most likely path to a cure. We describe the design and initial characterization of a kerateine (obtained by reductive extraction from keratin proteins) aerogel-electrospun polycaprolactone fiber scaffold system. The scaffolds mimic key features of the choroid and the Bruch's membrane, which is the basement membrane to which the cells of the retinal pigment epithelium (RPE) attach. The scaffolds had elastic moduli of 2-7.2 MPa, a similar range as native choroid and Bruch's membrane. ARPE-19 cells attached to the polycaprolactone fibers, remained viable for one week, and proliferated to form a monolayer reminiscent of that needed for retinal repair. These constructs could serve as a model system for testing cell and/or drug treatment strategies or directing ex vivo retinal tissue formation in the treatment of AMD.

Cell-Based Therapies for Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a leading cause of blindness worldwide. The pathogenesis of AMD involves dysfunction and loss of the retinal pigment epithelium (RPE), a monolayer of cells that provide nourishment and functional support for the overlying photoreceptors. RPE cells in mammals are not known to divide, renew or regenerate in vivo, and in advanced AMD, RPE loss leads to degeneration of the photoreceptors and impairment of vision. One possible therapeutic approach would be to support and replace the failing RPE cells of affected patients, and indeed moderate success of surgical procedures in which relatively healthy autologous RPE from the peripheral retina of the same eye was transplanted under the retina in the macular area suggested that RPE replacement could be a means to attenuate photoreceptor cell loss. This prompted exploration of the possibility to use pluripotent stem cells (PSCs) as a potential source for "healthy and young" RPE cells for such cell-based therapy of AMD. Various approaches ranging from the use of allogeneic embryonic stem cells to autologous induced pluripotent stem cells are now being tested within early clinical trials. Such PSC-derived RPE cells are either injected into the subretinal space as a suspension, or transplanted as a monolayer patch upon scaffold support. Although most of these approaches are at early clinical stages, safety of the RPE product has been demonstrated by several of these studies. Here, we review the concept of cell-based therapy of AMD and provide an update on current progress in the field of RPE transplantation.

Curcumin-loaded poly-ε-caprolactone nanoparticles show antioxidant and cytoprotective effects in the presence of reactive oxygen species

Interest in novel delivery systems that improve the cytoprotective and antioxidant effects of natural drugs has been explored recently due to the increase in the incidence of chronic diseases in which oxidation mechanisms are involved. Curcumin is a phenolic compound recently shown to be clinically significant due to its anti-inflammatory, anticancer, and antioxidant properties. However, this molecule possesses a low bioavailability and a high degradation rate in the presence of light. Therefore, we prepared nanoparticles of poly-ε-caprolactone and Pluronic® F-68 as a stabilizer and loaded these with curcumin (Cur–PCL nanoparticles) for antioxidant and cytoprotective applications. The nanoparticles did not induce cell death, but they did reduce cell proliferation without affecting cell migration and cell adhesion. Interestingly, Cur–PCL and poly-ε-caprolactone nanoparticles reduced the oxidative stress induced by hydrogen peroxide and presented a cytoprotective effect. Remarkably, poly-ε-caprolactone nanoparticles showed a decrement of 30% in reactive oxygen species presence compared to the positive control. The decrease of reactive oxygen species derived from the administration of poly-ε-caprolactone nanoparticles could be attributed to the presence of Pluronic® F-68. Taken together, these data indicated that these nanoparticles might have a clinical application in disorders related to reactive oxygen species formation.

A chitosan modified asymmetric small-diameter vascular graft with anti-thrombotic and anti-bacterial functions for vascular tissue engineering

Rapid endothelialization and prevention of restenosis are two vital challenges for the preparation of a small-diameter vascular graft (SDVG), while postoperative infection after implantation is often neglected.

From fiber curls to mesh waves: a platform for the fabrication of hierarchically structured nanofibers mimicking natural tissue formation

Bioinstructive scaffolds for regenerative medicine are characterized by intrinsic properties capable of directing cell response and promoting wound healing. The design of such scaffolds requires the incorporation of well-defined physical properties that mimic the native extracellular matrix (ECM). Here, inspired by epithelial tissue morphogenesis, we present a novel approach to code nanofiber materials with controlled hierarchical wavy structures resembling the configurations of native EMC fibers through using thermally shrinking materials as substrates onto which the fibers are deposited. This approach could serve as a platform for fabricating functional scaffolds mimicking various tissues such as trachea, iris, artery wall and ciliary body. Modeling affirms that the mechanical properties of the fabricated wavy fibers could be regulated through varying their wavy patterns. The nanofibrous scaffolds coded with wavy patterns show an enhanced cellular infiltration. In addition, we further investigated whether the wavy patterns could regulate transforming growth factor-beta (TGF-β) production, a key signalling pathway involved in connective tissue development. Our results demonstrated that nanofibrous scaffolds coded with wavy patterns could induce TGF-β expression without the addition of a soluble growth factor. Our new approach could open up new avenues for fabricating bioinstructive scaffolds for regenerative medicine.

Scaffolds for retinal pigment epithelial cell transplantation in age-related macular degeneration

In several retinal degenerative diseases, including age-related macular degeneration, the retinal pigment epithelium, a highly functionalized cell monolayer, becomes dysfunctional. These retinal diseases are marked by early retinal pigment epithelium dysfunction reducing its ability to maintain a healthy retina, hence making the retinal pigment epithelium an attractive target for treatment. Cell therapies, including bolus cell injections, have been investigated with mixed results. Since bolus cell injection does not promote the proper monolayer architecture, scaffolds seeded with retinal pigment epithelium cells and then implanted have been increasingly investigated. Such cell-seeded scaffolds address both the dysfunction of the retinal pigment epithelium cells and age-related retinal changes that inhibit the efficacy of cell-only therapies. Currently, several groups are investigating retinal therapies using seeded cells from a number of cell sources on a variety of scaffolds, such as degradable, non-degradable, natural, and artificial substrates. This review describes the variety of scaffolds that have been developed for the implantation of retinal pigment epithelium cells.

Magnetic poly(2-hydroxyethyl methacrylate) microspheres for affinity purification of monospecific anti-p46 kDa/Myo1C antibodies for early diagnosis of multiple sclerosis patients

The aim of the present study is to develop new magnetic polymer microspheres with functional groups available for easy protein and antibody binding. Monodisperse macroporous poly(2-hydroxyethyl methacrylate) (PHEMA-COOH) microspheres ~4 µm in diameter and containing ∼1 mmol COOH/g were synthesized by multistep swelling polymerization of 2-hydroxyethyl methacrylate (HEMA), ethylene dimethacrylate (EDMA), and 2-[(methoxycarbonyl)methoxy]ethyl methacrylate (MCMEMA), which was followed by MCMEMA hydrolysis. The microspheres were rendered magnetic by precipitation of iron oxide inside the pores, which made them easily separable in a magnetic field. Properties of the resulting magnetic poly(2-hydroxyethyl methacrylate) (mgt.PHEMA) particles with COOH functionality were examined by scanning and transmission electron microscopy (SEM and TEM), static volumetric adsorption of helium and nitrogen, mercury porosimetry, Fourier transform infrared (FTIR) and atomic absorption spectroscopy (AAS), and elemental analysis. Mgt.PHEMA microspheres were coupled with p46/Myo1C protein purified from blood serum of multiple sclerosis (MS) patients, which enabled easy isolation of monospecific anti-p46/Myo1C immunoglobulin G (IgG) antibodies from crude antibody preparations of mouse blood serum. High efficiency of this approach was confirmed by SDS/PAGE, Western blot, and dot blot analyses. The newly developed mgt.PHEMA microspheres conjugated with a potential disease biomarker, p46/Myo1C protein, are thus a promising tool for affinity purification of antibodies, which can improve diagnosis and treatment of MS patients.

Synthesis and characterization of nanoscale zeolitic imidazolate frameworks with ciprofloxacin and their applications as antimicrobial agents

The present study investigated antibiotic drug loading in metal–organic frameworks (MOFs).

Small Diameter Blood Vessels Bioengineered From Human Adipose-derived Stem Cells

Bioengineering of small-diameter blood vessels offers a promising approach to reduce the morbidity associated with coronary artery and peripheral vascular disease. The aim of this study was to construct a two-layered small-diameter blood vessel using smooth muscle cells (SMCs) and endothelial cells (ECs) differentiated from human adipose-derived stem cells (hASCs). The outer layer was constructed with biodegradable polycaprolactone (PCL)-gelatin mesh seeded with SMCs, and this complex was then rolled around a silicone tube under pulsatile stimulation. After incubation for 6 to 8 weeks, the PCL-gelatin degraded and the luminal supporting silicone tube was removed. The smooth muscle layer was subsequently lined with ECs differentiated from hASCs after stimulation with VEGF and BMP4 in combination hypoxia. The phenotype of differentiated SMCs and ECs, and the cytotoxicity of the scaffold and biomechanical assessment were analyzed. Our results demonstrated that the two-layered bioengineered vessels exhibited biomechanical properties similar to normal human saphenous veins (HSV). Therefore, hASCs provide SMCs and ECs for bioengineering of small-diameter blood vessels.

Shish-kebab-structured poly(ε-caprolactone) nanofibers hierarchically decorated with chitosan-poly(ε-caprolactone) copolymers for bone tissue engineering

In this work, scaffolds with a shish-kebab (SK) structure formed by poly(ε-caprolactone) (PCL) nanofibers and chitosan-PCL (CS-PCL) copolymers were prepared via electrospinning and subsequent crystallization for bone tissue engineering applications. The aim of this study was to introduce nanosized topography and the high biocompatibility of chitosan onto PCL nanofibers to enhance cell affinity to PCL scaffolds. CS-PCL copolymers with various ratios were synthesized, and then spontaneously crystallized as kebabs onto the electrospun PCL fibers, which acted as shishes. Scanning electron microscopy (SEM) results demonstrated that the copolymer with PCL to chitosan ratio of 8.8 could hierarchically decorate the PCL nanofibers and formed well-shaped kebabs on the PCL nanofiber surface. Water contact angle tests and biomimetic activity experiments revealed that the shish-kebab scaffolds with CS-PCL kebabs (PCL-SK(CS-PCL(8.8))) showed enhanced hydrophilicity and mineralization ability compared with smooth PCL and PCL-SK(PCL) shish-kebab scaffolds. Osteoblast-like MG63 cells cultured on the PCL-SK(CS-PCL(8.8)) scaffolds showed optimizing cell attachment, cell viability, and metabolic activity, demonstrating that this kind of scaffold has potential applications in bone tissue engineering.

A comparative mechanical and biocompatibility study of poly(ε-caprolactone), hybrid poly(ε-caprolactone)–silk, and silk nanofibers by colloidal electrospinning technique for tissue engineering

Poly(ε-caprolactone) is an established polymer used in the fabrication of scaffolds for tissue engineering applications. Poly(ε-caprolactone)’s intrinsic hydrophobicity and toxicity, however, is greater than other natural polymers which limits its applicability. In this study, these problems were addressed by the modification of poly(ε-caprolactone) nanofibers with nanoparticles made from natural polymers, such as silk fibroin. Silk fibroin nanoparticles were prepared by desolvation and blended with poly(ε-caprolactone) to form a colloidal solution capable of forming nanofibers by electrospinning. Fabricated silk fibroin nanoparticles and three different nanofibers were characterized by transmission electron microscopy, variable pressure field emission scanning electron microscope, contact angle, Fourier transform infrared spectroscopy, thermogravimetric analysis, as well as an evaluation of their mechanical properties. The hybrid nanofibers incorporated with silk nanoparticles improved water absorbability compared to pure poly(ε-caprolactone) nanofibers and had much better mechanical properties than the silk fibroin nanofibers. The cytotoxicity and cell attachment tests were carried by culturing NIH 3T3 fibroblasts with the nanofibers. The hybrid nanofibers exhibited better cell viability and cell attachment than the pure poly(ε-caprolactone) nanofibers. Furthermore, the silk fibroin nanoparticles improved the water contact angle and enhanced cell interaction compared to the unmodified poly(ε-caprolactone). Based on these results, the modification of poly(ε-caprolactone) nanofibers with silk nanoparticles is a promising strategy for the improvement of poly(ε-caprolactone)-based nanofibers for future tissue engineering applications.

Correlation of platelet activating factor and age-related macular degeneration

OBJECTIVE

To investigate the role of Platelet Activating Factor (PAF) in the pathogenesis and development of Age-Related Macular Degeneration (ARMD).

RESEARCH DESIGN AND METHODS

Fifty six patients with ARMD (24 patients with dry ARMD and 32 patients with wet ARMD) and 25 age-matched control participants underwent ophthalmological examination, including visual acuity measurement and evaluation of the retina. The participants were classified into three groups according to their retinal status, based on indirect fundoscopy, Optical Coherence Tomography and fluorescein angiography findings. In order to evaluate the concentrations of PAF in serum, blood samples were collected from all participants and were analyzed with ELISA technique.

RESULTS

The concentrations of PAF differed significantly according to macular lesions and were found to be lower in patients with ARMD than control participants.

CONCLUSIONS

PAF levels are decreased along with the severity of ARMD. Understanding the role of PAF in pathogenesis of ARMD could be the impetus for the development of new therapies field of treatment of ARMD or even other retinal diseases.

Angiogenesis in bone regeneration: tailored calcium release in hybrid fibrous scaffolds

In bone regeneration, silicon-based calcium phosphate glasses (Bioglasses) have been widely used since the 1970s. However, they dissolve very slowly because of their high amount of Si (SiO2 > 45%). Recently, our group has found that calcium ions released by the degradation of glasses in which the job of silicon is done by just 5% of TiO2 are effective angiogenic promoters, because of their stimulation of a cell-membrane calcium sensing receptor (CaSR). Based on this, other focused tests on angiogenesis have found that Bioglasses also have the potential to be angiogenic promoters even with high contents of silicon (80%); however, their slow degradation is still a problem, as the levels of silicon cannot be decreased any lower than 45%. In this work, we propose a new generation of hybrid organically modified glasses, ormoglasses, that enable the levels of silicon to be reduced, therefore speeding up the degradation process. Using electrospinning as a faithful way to mimic the extracellular matrix (ECM), we successfully produced hybrid fibrous mats with three different contents of Si (40, 52, and 70%), and thus three different calcium ion release rates, using an ormoglass-polycaprolactone blend approach. These mats offered a good platform to evaluate different calcium release rates as osteogenic promoters in an in vivo subcutaneous environment. Complementary data were collected to complement Ca(2+) release analysis, such as stiffness evaluation by AFM, ζ-potential, morphology evaluation by FESEM, proliferation and differentiation analysis, as well as in vivo subcutaneous implantations. Material and biological characterization suggested that compositions of organic/inorganic hybrid materials with a Si content equivalent to 40%, which were also those that released more calcium, were osteogenic. They also showed a greater ability to form blood vessels. These results suggest that Si-based ormoglasses can be considered an efficient tool for calcium release modulation, which could play a key role in the angiogenic promoting process.

Controlled release of tinidazole and theophylline from chitosan based composite hydrogels

Several composite hydrogels were synthesized by free radical crosslink copolymerization of acrylic acid (AA) and N' methylene bis-acrylamide (MBA) in the presence of chitosan (CS). During polymerization CS was incorporated in situ in the crosslinked polyacrylic acid gel to produce composite hydrogels. The structure and properties of the hydrogels were characterized by FTIR, (13)C NMR, DTA-TGA, XRD, swelling and diffusion characteristic and also network parameters. The loading and the in vitro release behaviours of theophylline and tinidazole model drugs were studied with these hydrogels. The wt% of CS and MBA and pH of the medium was found to strongly influence the drug release behaviour of the gels. Accordingly, the release rate of these two drugs was much faster at pH of 7.6 than at pH 1.5.

Synthesis and characterization of curcumin loaded polymer/lipid based nanoparticles and evaluation of their antitumor effects on MCF-7 cells

BACKGROUND

Hybrid materials are synthesized using hydrophilic polymer and lipids which ensure their long term systemic circulation through intravenous administration and enhance loading of hydrophobic drugs. The purpose of this study is to prepare, characterize and evaluate the in vitro efficacy of curcumin loaded poly-hydroxyethyl methacrylate/stearic acid nanoparticles in MCF-7.

METHODS

C-PSA-NPs, prepared using the emulsification-solvent evaporation method were characterized by dynamic laser scattering, SEM, AFM, FT-IR, X-ray diffraction, and TGA. The in vitro release behavior was observed in PBS pH7.4, the anticancer potential was analyzed by MTT assay, cell cycle and apoptosis studies were performed through flow cytometry. C-PSA-NPs drug localization and cancer cell morphological changes were analyzed in MCF-7 cell line.

RESULTS

C-PSA-NPs exhibited the mean particle size in the range of 184nm with no aggregation. The surface charge of the material was around -29.3mV. Thermal studies (TGA) and surface chemistry studies (FT-IR, XRD) showed the existence of drug curcumin in C-PSA-NPs. The MTT assay indicated higher anticancer properties and flow cytometry studies revealed that there were better apoptotic activity and maximum localization of C-PSA-NPs than curcumin.

CONCLUSIONS

Polymer lipid based drug delivery appeared as one of the advancements in drug delivery systems. Through the present study, a novel polymer lipid based nanocarrier delivery system loaded with curcumin was demonstrated as an effective and potential alternative method for tumor treatment in MCF-7 cell line.

GENERAL SIGNIFICANCE

C-PSA-NPs exhibited potent anticancer activity in MCF-7 cell line and it indicates that C-PSA-NPs are a suitable carrier for curcumin.

Scaffolds and stem cells: delivery of cell transplants for retinal degenerations

Retinal degenerations and optic neuropathies often lead to death of photoreceptors or retinal ganglion cells, respectively. Stem cell therapies are showing promise for these diseases in preclinical models and are beginning to transition into human trials, but cell delivery and integration remain major challenges. Focusing on photoreceptor- and progenitor-directed approaches, in this article, the authors review how advances in tissue engineering and cell scaffold design are enhancing cell therapies for retinal degeneration.

Curcumin loaded poly(2-hydroxyethyl methacrylate) nanoparticles from gelled ionic liquid--in vitro cytotoxicity and anti-cancer activity in SKOV-3 cells

The main focus of this study is to encapsulate hydrophobic drug curcumin in hydrophilic polymeric core such as poly(2-hydroxyethyl methacrylate) [PHEMA] nanoparticles from gelled ionic liquid (IL) to improve its efficacy. We have achieved 26.4% drug loading in a biocompatible hydrophilic polymer. Curcumin loaded PHEMA nanoparticles (C-PHEMA-NPs) were prepared by nano-precipitation method. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis showed that the prepared nanoparticles were spherical in shape and free from aggregation. The size and zeta potential of prepared C-PHEMA-NPs were about 300 nm and -33.4 mV respectively. C-PHEMA-NPs were further characterized by FT-IR spectroscopy which confirmed the existence of curcumin in the nanoparticles. X-ray diffraction and differential scanning calorimetry studies revealed that curcumin present in the PHEMA nanoparticles were found to be amorphous in nature. The anticancer activity of C-PHEMA-NPs was measured in ovarian cancer cells (SKOV-3) in vitro, and the results revealed that the C-PHEMA-NPs had better tumor cells regression activity than free curcumin. Flow cytometry showed the significant reduction in G0/G1 cells after treatment with C-PHEMA-NPs and molecular level of apoptosis were also studied using western blotting. Toxicity of PHEMA nanoparticles were studied in zebrafish embryo model and results revealed the material to be highly biocompatible. The present study demonstrates the curcumin loaded PHEMA nanoparticles have potential therapeutic values in the treatment of cancer.

Synthesis and characterization of chitosan-multiwalled carbon nanotubes/hydroxyapatite nanocomposites for bone tissue engineering

Chitosan-multiwalled carbon nanotubes/hydroxyapatite nanocomposites were synthesized by a novel in situ precipitation method. The electrostatic adsorption between multiwalled carbon nanotubes and chitosan was investigated and explained by Fourier transform infrared spectroscopy analysis. Morphology studies showed that uniform distribution of hydroxyapatite particles and multiwalled carbon nanotubes in the polymer matrix was observed. In chitosan-multiwalled carbon nanotubes/hydroxyapatite nanocomposites, the diameters of multiwalled carbon nanotubes were about 10 nm. The mechanical properties of the composites were evaluated by measuring their compressive strength and elastic modulus. The elastic modulus and compressive strength increased sharply from 509.9 to 1089.1 MPa and from 33.2 to 105.5 MPa with an increase of multiwalled carbon/chitosan weight ratios from 0 to 5 %, respectively. Finally, the cell biocompatibility of the composites was tested in vitro, which showed that they have good biocompatibility. These results suggest that the chitosan-multiwalled carbon nanotubes/hydroxyapatite nanocomposites are promising biomaterials for bone tissue engineering.

Release behavior and toxicity profiles towards A549 cell lines of ciprofloxacin from its layered zinc hydroxide intercalation compound

Background

Layered hydroxides salts (LHS), a layered inorganic compound is gaining attention in a wide range of applications, particularly due to its unique anion exchange properties. In this work, layered zinc hydroxide nitrate (LZH), a family member of LHS was intercalated with anionic ciprofloxacin (CFX), a broad spectrum antibiotic via ion exchange in a mixture solution of water:ethanol.

Results

Powder x-ray diffraction (XRD), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA) confirmed the drug anions were successfully intercalated in the interlayer space of LZH. Specific surface area of the obtained compound was increased compared to that of the host due to the different pore textures between the two materials. CFX anions were slowly released over 80 hours in phosphate-buffered saline (PBS) solution due to strong interactions that occurred between the intercalated anions and the host lattices. The intercalation compound demonstrated enhanced antiproliferative effects towards A549 cancer cells compared to the toxicity of CFX alone.

Conclusions

Strong host-guest interactions between the LZH lattice and the CFX anion give rise to a new intercalation compound that demonstrates sustained release mode and enhanced toxicity effects towards A549 cell lines. These findings should serve as foundations towards further developments of the brucite-like host material in drug delivery systems.

Nanocrystalline hydroxyapatite and zinc-doped hydroxyapatite as carrier material for controlled delivery of ciprofloxacin

In bone disorders infections are common. The concentration of majority of antibiotics is very low in the bone tissue. A high local dose can be obtained from the ciprofloxacin-loaded hydroxyapatite nanoparticles. The present study is aimed at developing the use of hydroxyapatite and zinc-doped hydroxyapatite nanoparticles as a carrier for ciprofloxacin drug delivery system. The ciprofloxacin-loaded hydroxyapatite and zinc-doped hydroxyapatite have a good antibacterial activity against Pseudomonas aeruginosa and Staphylococcus aureus. Hydroxyapatite and zinc-doped hydroxyapatite were prepared and characterized using X-ray diffraction, Transmission electron microscopy and inductively coupled plasma optical emission spectrometry. They were loaded with ciprofloxacin using optimized drug loading parameters. Drug loading, in vitro drug release and antimicrobial activity were analyzed. The influence of zinc on the controlled release of ciprofloxacin was analyzed. The results show that the presence of zinc increases the drug release percentage and that the drug was released in a controlled manner.