Long-Term Implantability of Resorbable Carboxymethyl Cellulose/Chitosan Microspheres in a Rabbit Renal Arterial Embolization Model.

Purpose: To determine the physiologic response to resorbable carboxymethyl cellulose/chitosan (CMC/CN) microspheres in a long-term rabbit model, including the clinical response, gross pathology, and histopathology.

Materials And Methods: Six rabbits were embolized with CMC/CN microspheres (300-500 µm) in one kidney via an inferior renal artery branch. Angiography was performed immediately before and after embolization and prior to killing at 6 months (180 ± 7 days, n = 3) and 12 months (365 ± 10 days, n = 3).

In vitro evaluation of sunitinib loaded bioresorbable microspheres for potential application in arterial chemoembolization.

Drug-loadable bioresorbable microspheres (BRMS) are designed for treating hypervascular tumors through chemoembolization, thereby reducing systemic side effects via controllable local delivery. The present study investigated the degradation and loading capability of bioresorbable microspheres with an anti-angiogenic agent, sunitinib, and then evaluated the release profiles in different media (PBS, 10μg/mL and 4mg/mL lysozyme solutions), and tested catheter deliverability as well as potential antiangiogenic effects of the loaded microspheres. The dry weight of the BRMS showed a consistent decrease over the period of incubation in a 10μg/mL lysozyme solution with 61.

In vitro comparative study of drug loading and delivery properties of bioresorbable microspheres and LC bead.

Drug loadable bioresorbable microspheres (BRMS) are specially designed for the treatment of hypervascular tumors through arterial embolization. These microspheres consist of carboxymethyl chitosan crosslinked with carboxymethyl cellulose, and are available at different size ranges varying from 50 to 900 µm in diameter. Similar to commercially available non-resorbable drug eluting microspheres, LC Bead microspheres (LCB), BRMS were capable of loading more than 99 % of doxorubicin, an anticancer drug, from the solution within 2 h with highly similar kinetics (difference factor f  = 0.

Intra-articular treatment of knee osteoarthritis: from anti-inflammatories to products of regenerative medicine.

Objectives: Knee osteoarthritis (OA) is a debilitating condition that may ultimately require total knee arthroplasty (TKA). Non-operative treatments are bracing, oral analgesics, physical therapy, and intra-articular knee injection (IAKI). The objective of this paper is to provide a systematic literature review regarding intra-articular treatment of knee OA and insight into promising new products of regenerative medicine that may eventually have a substantial effect on treatment.

Calibrated Bioresorbable Microspheres as an Embolic Agent: An Experimental Study in a Rabbit Renal Model.

Purpose: To evaluate the time frame of resorption and tissue response of newly developed bioresorbable microspheres (BRMS) and vessel recanalization after renal embolization.

Materials And Methods: Embolization of lower poles of kidneys of 20 adult rabbits was performed with BRMS (300-500 µm). Two rabbits were sacrificed immediately after embolization (day 0).

Calibrated bioresorbable microspheres: a preliminary study on the level of occlusion and arterial distribution in a rabbit kidney model.

Purpose: To assess the level of occlusion and arterial distribution of calibrated bioresorbable microspheres (BRMS-I and BRMS-II) compared with tris-acryl gelatin microspheres (TGMS) after renal embolization.

Materials And Methods: Six rabbits underwent renal embolization with 100-300 µm BRMS-I and TGMS; three rabbits received partial occlusion (group 1, n = 3), and three rabbits received total occlusion (group 2, n = 3). Four other rabbits received 100-300 µm BRMS-II (with higher cross-linking density than BRMS-I) in the left kidneys reaching total occlusion (group 3, n = 4).

An in situ forming biodegradable hydrogel-based embolic agent for interventional therapies.

We present here the characteristics of an in situ forming hydrogel prepared from carboxymethyl chitosan and oxidized carboxymethyl cellulose for interventional therapies. Gelation, owing to the formation of Schiff bases, occurred both with and without the presence of a radiographic contrast agent. The hydrogel exhibited a highly porous internal structure (pore diameter 17±4 μm), no cytotoxicity to human umbilical vein endothelial cells, hemocompatibility with human blood, and degradability in lysozyme solutions.

In vitro and in vivo evaluation of biodegradable embolic microspheres with tunable anticancer drug release.

Natural polymer-derived materials have attracted increasing interest in the biomedical field. Polysaccharides have obvious advantages over other polymers employed for biomedical applications due to their exceptional biocompatibility and biodegradability. None of the spherical embolic agents used clinically is biodegradable.

Bioresorbable hydrogel microspheres for transcatheter embolization: preparation and in vitro evaluation.

Purpose: To develop and evaluate a bioresorbable spherical material for embolization.

Materials And Methods: New bioresorbable hydrogel microspheres were prepared from carboxymethyl cellulose and chitosan by using an inverse emulsion method. Size distribution of the microspheres was determined with a microscope, and the colorability was tested with Evans blue dye.

Doxorubicin loading and eluting characteristics of bioresorbable hydrogel microspheres: in vitro study.

Non-bioresorbable drug eluting microspheres are being increasingly used for the treatment of unresectable liver tumors, whereas bioresorbable microspheres have not received much attention. In this study, bioresorbable microspheres prepared from chitosan and carboxymethyl cellulose were loaded with doxorubicin (Doxo) via ion-exchange interactions with carboxylic groups in the microspheres. With a 25-40% decrease in the microsphere size depending on their size ranges, the microspheres could load a maximum of 0.

Novel macromolecular crosslinking hydrogel to reduce intra-abdominal adhesions.

Background: The aim of this study was to compare the anti-adhesion efficacy of a biodegradable, in situ, macromolecular cross-linking hydrogel made from oxidized dextran/N-carboxyethyl chitosan (Odex/CEC) with a commercially available carboxymethylcellulose/modified hyaluronan barrier film (Seprafilm; Genzyme Corporation, Cambridge, MA) in a rat cecum abrasion model.

Methods: The rat model utilized a cecal abrasion and abdominal wall insult surgical protocol. The 2% Odex/CEC hydrogel treatment was applied by syringe to coat both the cecal and the abdominal wall insults, while other animals were treated with Seprafilm applied to the cecal injury only.

In vitro and in vivo suppression of cellular activity by guanidinoethyl disulfide released from hydrogel microspheres composed of partially oxidized hyaluronan and gelatin.

This paper describes the preparation of oxidized hyaluronan crosslinked gelatin microspheres for drug delivery. Microspheres were prepared by a modified water-in-oil-emulsion crosslinking method, where three-dimensional crosslinked hydrogel microspheres formed in the absence of any extraneous crosslinker. SEM analyses of the microspheres showed rough surfaces in their dried state with an average diameter of 90 microm.

Non-cytotoxic, in situ gelable hydrogels composed of N-carboxyethyl chitosan and oxidized dextran.

A series of in situ gelable hydrogels were prepared from oxidized dextran (Odex) and N-carboxyethyl chitosan (CEC) without any extraneous crosslinking agent. The gelation readily took place at physiological pH and body temperature. The gelation process was monitored rheologically, and the effect of the oxidation degree of dextran on the gelation process was investigated.

Mechanically strong double network photocrosslinked hydrogels from N,N-dimethylacrylamide and glycidyl methacrylated hyaluronan.

Hyaluronan (HA) is a natural polysaccharide abundant in biological tissues and it can be modified to prepare biomaterials. In this work, HA modified with glycidyl methacrylate was photocrosslinked to form the first network (PHA), and then a series of highly porous PHA/N,N-dimethylacrylamide (DAAm) hydrogels (PHA/DAAm) with high mechanical strength were obtained by incorporating a second network of photocrosslinked DAAm into PHA network. Due to the synergistic effect produced by double network (DN) structure, despite containing 90% of water, the resulting PHA/DAAm hydrogel showed a compressive modulus and a fracture stress over 0.

Self-crosslinkable hydrogels composed of partially oxidized hyaluronan and gelatin: in vitro and in vivo responses.

Self-crosslinkable hydrogels had been formulated from two precursors, partially oxidized hyaluronan (oHA) and gelatin. The physicochemical properties of the resulting hydrogels have been elucidated by instrumental analyses (FTIR, SEM, and rheometry). These hydrogels were highly porous with an average pore size of 60 microm, and evidently, accommodative to cell infiltration.

Material properties in unconfined compression of human nucleus pulposus, injectable hyaluronic acid-based hydrogels and tissue engineering scaffolds.

Surgical treatment for lower back pain related to degenerative disc disease commonly includes discectomy and spinal fusion. While surgical intervention may provide short-term pain relief, it results in altered biomechanics of the spine and may lead to further degenerative changes in adjacent segments. One non-fusion technique currently being investigated is nucleus pulposus (NP) support via either an injectable hydrogel or tissue engineered construct.

Long-range self-governing motion of polymer gel on a gradiently charged insulating substrate.

Herein, we report a special poly(vinyl alcohol)/dimethylsulfoxide (PVA/DMSO) gel electromechanical system with great self-governed capability. The system is operated in air by applying a noncontacted DC electric field. When the applied electric field exceeds a certain critical value, the gel exhibits fast and self-governing locomotion on the gradiently charged glass substrate.

Rheological characterization of in situ crosslinkable hydrogels formulated from oxidized dextran and N-carboxyethyl chitosan.

The gelation kinetics of an in situ gelable hydrogel formulated from oxidized dextran (Odex) and N-carboxyethyl chitosan (CEC) was investigated rheologically. Both Schiff base mediated chemical and physical crosslinking account for its rapid gelation (30-600 s) between 5 and 37 degrees C. The correlation between gelation kinetics and hydrogel properties with Odex/CEC concentration, their feed ratio, and temperature were elucidated.

Biologically inspired path-controlled linear locomotion of polymer gel in air.

A novel approach based on electrohydrodynamic behavior of a dielectric liquid pattern in electric field was developed to fabricate a poly(vinyl alcohol)/dimethyl sulfoxide (PVA/DMSO) gel electromechanical system. Driving experiments indicate that this system could be well-operated in air by using a direct current (DC) electric field, and the gel exhibits a long-range path-controlled snaillike or snakelike motion with a fast crawling speed of 14.4 mm/s.

Protein diffusion in agarose hydrogel in situ measured by improved refractive index method.

The accurate knowledge of the diffusion behavior of protein within biomimetic hydrogel matrix at body temperature has a great implication for the design of efficient controlled release protein-base drug delivery devices. In this paper, we improved our previous in situ refractive index method with great temperature-controlled capability. For the first time, this newly improved method was employed to study the diffusion of protein (bovine serum albumin (BSA) and lysozyme) in agarose hydrogel at body temperature (37 degrees C).

Biocomposites of plasticized starch reinforced with cellulose crystallites from cottonseed linter.

Environmentally friendly starch biocomposites were successfully developed using a colloidal suspension of cottonseed linter cellulose crystallite as a filler to reinforce glycerol plasticized starch (PS). The cellulose crystallites, having lengths of 350 +/- 70 nm and diameters of 40 +/- 8 nm on average, were prepared from cottonseed linters by acid hydrolysis. The dependence of morphology and properties of the PS-based biocomposites on cellulose crystallites content in the range from 0 to 30 wt.

Thermal gelation of cellulose in a NaOH/thiourea aqueous solution.

Utilizing a novel solvent of cellulose, 6 wt % NaOH/5 wt % thiourea aqueous solution, for the first time, we prepared the thermally induced cellulose gel. We investigated the thermal gelation of cellulose solutions with rheometry and the structure of the gel with 13C NMR, wide-angle X-ray diffraction, environmental scanning electron microscopy, and atomic force microscopy. The cellulose solutions revealed an increase in both the storage modulus (G') and the loss modulus (G") with an increase in the temperature during gelation.

In situ investigation of drug diffusion in hydrogels by the refractive index method.

This work describes a simple but novel analytical method for in situ monitoring of the diffusion process of drugs in hydrogels based on refractive index measurements. The diffusion process was monitored by recording the refraction of a laser beam passing through a triangular cell, which allows the determination of changes in the refractive index distribution from the deviated distance of the linear beam. Compared to conventional methods, this new method exhibits advantages such as more simplicity, lower cost, and speed.