Extraction and In Vitro Skincare Effect Assessment of Polysaccharides Extract from the Roots of Abelmoschus manihot (L.).

Obtaining high-added value compounds from agricultural waste receives increasing attention, as it can both improve resource utilization efficiency and reduce waste generation. In this study, polysaccharides are extracted from the discarded roots of Abelmoschus manihot (L.) by the high-efficiency ultrasound-assisted extraction (UAE). The optimized condition was determined as solid-liquid ratio SL ratio = 1:20, temperature T = 30 °C and time T = 40 min, achieving an extraction yield of 13.41%. Composition analysis revealed that glucose (Glc, 44.65%), rhamnose (Rha, 26.30%), galacturonic acid (GalA, 12.50%) and galactose (Gal, 9.86%) are the major monosaccharides of the extract. The extract showed a low degree of esterification (DE) value of 40.95%, and its Fourier-transform infrared (FT-IR) spectrum exhibited several characteristic peaks of polysaccharides. Inspired by the wide cosmetic applications of polysaccharides, the skincare effect of the extract was evaluated via the moisture retention, total phenolic content (TPC) quantification, 2,2-Diphenyl-1-picrylhydrazyl (DPPH)-free radical scavenging activity, anti-hyaluronidase and anti-elastase activity experiments. The extract solutions demonstrated a 48 h moisture retention rate of 10.75%, which is superior to that of commercially available moisturizer hyaluronic acid (HA). Moreover, both the TPC value of 16.16 mg GAE/g (dw) and DPPH-free radical scavenging activity of 89.20% at the concentration of 2 mg/mL indicated the strong anti-oxidant properties of the extract. Furthermore, the anti-hyaluronidase activity and moderate anti-elastase activity were determined as 72.16% and 42.02%, respectively. In general, in vitro skincare effect experiments suggest moisturizing, anti-oxidant, anti-radical and anti-aging activities of the A. manihot root extract, indicating its potential applications in the cosmetic industry.

Assessment of calcium alginate gels as wall materials for encapsulation systems.

BACKGROUND: Calcium alginate gels are widely used to encapsulate active compounds. Some characteristic parameters of these gels are necessary to describe the release of active compounds through mechanistic mathematical models. In this work, transport and kinetics properties of calcium alginate gels were determined through simple experimental techniques. RESULTS: The weight-average molecular weight ( M ¯ w = 192 × 103 Da) and the fraction of residues of α-l-guluronic acid ( F G = 0.356) of sodium alginate were determined by capillary viscometry and 1 H-nuclear magnetic resonance at 25 °C, respectively. Considering the half egg-box model, both values were used to estimate the molecular weight of calcium alginate as M g = 2.02 × 105 Da. An effective diffusion coefficient of water ( D eff , w = 2.256 × 10-9 m2 s-1 ) in calcium alginate was determined using a diffusion cell at 37 °C. Finally, a kinetics constant of depolymerization ( k m = 9.72 × 10-9 m3 mol-1 s-1 ) of calcium alginate was obtained considering dissolution of calcium to a medium under intestinal conditions. CONCLUSION: The experimental techniques used are simple and easily reproducible. The obtained values may be useful in the design, production, and optimization of the alginate-based delivery systems that require specific release kinetics of the encapsulated active compounds. © 2023 Society of Chemical Industry.

Assessment of Biochemical Determinants in Multiple Sclerosis Patients Following the Oral Administration of ß-D-Mannuronic Acid (M2000).

BACKGROUND: Multiple sclerosis is an autoimmune chronic inflammatory disease of the central nervous system that can lead to some serious disabilities. Despite using various immunomodulatory and anti-inflammatory drugs that have therapeutic effects, they cannot reduce its progression completely and have some unwanted side effects too. The immunomodulatory and anti-inflammatory effects of the ß-D-Mannuronic acid (M2000) have been proven in several surveys, and the present research was designed to determine its toxicity and therapeutic effects in MS patients. METHODS: This study was performed on 15 MS patients who took 25 mg/kg/day the oral form of the ß-D-Mannuronic acid for six months, and 15 healthy people as a control group. Serum levels of Urea, Creatinine, GGT, Vitamin D3, Uric acid, and Anti-Phospholipids were compared to evaluate the therapeutic and possible toxic effects of this drug after this period. RESULTS: Non- toxic effects through the study of urea, creatinine, GGT, and non-significant changes in uric acid and anti-Phospholipids levels, besides a significant rise in vitamin, D3 levels in the M2000 treated cases were found. CONCLUSIONS: Our results suggested that ß-D-Mannuronic acid is a safe drug and has no toxicity when administered orally and also has some therapeutic effects in MS patients.

A randomized clinical trial for the assessment of the efficacy and safety of guluronic acid (G2013) in patients with rheumatoid arthritis.

Objective: To evaluate the safety, efficacy and tolerability of guluronic acid (G2013) in order to treat the rheumatoid arthritis patients who had inadequate response to conventional drugs. Methods: A randomized, 12-week clinical trial with two treatment arms: guluronic acid (G2013) and conventional treatment was performed. The diagnosed RA patients according to the ACR/European League against Rheumatism 2010 classification criteria, with an active disease at baseline that had inadequate response to conventional therapy were considered for the study. G2013 was administered orally twice a day with capsules of 500 mg during a period of 12 weeks and the patients were followed up for the safety and efficacy. Results: Our data showed that, the mean changes in the G2013 and control groups were -7.54 and -2.5 for tender joint count; -7.59 and -3.59 for swollen joint count; -30 and -0.9 for physician global assessment; -23.18 and -1.81 for patient global assessment; -14.45 and -1.45 for erythrocyte sedimentation rate, respectively. Improvements seen with G2013 were significantly greater than those with conventional drugs. In total, in 15.3% of G2013-treated patients and 69.2% of conventional-treated patients adverse events (AEs) occurred in this study. Conclusion: These data from routine rheumatology clinical practice highlight the effectivenessof G2013 in combination with conventional therapy with more desirable safety profile compared to the conventional-treated patients. Therefore, G2013 therapy could be an appropriate choice in order to manage the RA disease. (Clinical trial identifier: IRCT2016092813739N5).

An in vitro assessment for evaluating the efficiency of ß-d-mannuronic acid (M2000) in myelodysplastic syndrome.

ß-d-Mannuronic acid (M2000), a novel non-steroidal anti-inflammatory drug (NSAID) with immunosuppressive properties, has been previously shown to exhibit potential therapeutic effects on autoimmune diseases. Immunosuppression therapy has been a standard approach for myelodysplastic syndrome (MDS) for many years. We evaluated the effect of M2000 on isolated peripheral blood mononuclear cells (PBMCs) from patients with MDS. The PBMCs were isolated from 13 patients with MDS and 13 normal donors. The cells were then treated with low, moderate, and high doses of M2000 and diclofenac as a control group. The level of interleukin (IL)-6, tumor necrosis factor alpha (TNF-α), IL-3, granulocyte colony-stimulating factor (G-CSF) gene expression and the serum level of IL-6 and TNF-α production were evaluated by real-time polymerase chain reaction and enzyme-linked immunosorbent assay methods, respectively. Our findings indicated a significant reduction in the production of IL-6 and TNF-α as inflammatory cytokines. Furthermore, the level of G-CSF gene expression was significantly increased. In conclusion, M2000, a newly designed NSAID, has a remarkable effect on isolated PBMC in patients with MDS, which might bring a potential hope for its oral administrations in these patients.

Assessment of immunological profile in ankylosing spondylitis patients following a clinical trial with guluronic acid (G2013), as a new NSAID with immunomodulatory properties.

The present research aims to study the effects of guluronic acid (G2013) on gene expression levels of the T-bet, GATA3, RORγt, AHR, and FOXP3 transcription factors and on gene expression of their related cytokines following oral administration of this drug in ankylosing spondylitis (AS) patients. In this trial (clinical trial identifier: IRCT2016091813739N4), 14 AS patients and 12 age- and sex-matched healthy individuals were enrolled. The level of transcription factors' gene expression and expression of their related cytokines were measured by quantitative real-time PCR, before and 3 months after G2013 therapy. Our data indicated that the gene expression levels of the T-bet and IFN-γ were not significantly reduced during 12 weeks of treatment with G2013 (p > 0.05). The findings showed that the gene expression levels of the GATA3 and IL-4 increased significantly during 12 weeks of treatment with G2013 (p < 0.05). In addition, gene expression levels of the RORγt, IL-17, AHR, and IL-22 decreased significantly during the 12-week treatment with G2013 (p < 0.05). Moreover, the gene expression level of the FOXP3 increased significantly during 12 weeks of treatment with G2013, but the gene expression level of IL-10 did not increase significantly (p < 0.05, p > 0.05, respectively). The present study showed that oral intake of G2013 was able to modify the severity of articular and inflammatory symptoms of AS through reducing the gene expression levels of the RORγt, IL-17, AHR, and IL-22 and increasing the gene expression levels of the GATA3, IL-4, and FOXP3.

High precision microfluidic microencapsulation of bacteriophages for enteric delivery.

A Salmonella specific bacteriophage Felix O1 (Myoviridae) was microencapsulated in a pH responsive polymer formulation. The formulation incorporated a pH responsive methacrylic acid copolymer Eudragit® S100 (10% (w/v)) with the addition of the biopolymer sodium alginate, the composition of which was varied in the range (0.5% (w/v)-2% (w/v)). The microencapsulation process employed commercially available microfluidic droplet generation devices. We have used readily available low cost microfluidic chips instead of bespoke in-house fabricated glass capillary devices which are accessible only in specialist research facilities. We show that these co-flow microfluidic devices can easily be used to prepare phage encapsulated microparticles making them suitable for use by both the phage research community and industry in order to evaluate and optimise phage compatible formulations for microencapsulation. A novelty of the work reported here is that the size of the generated monodispersed droplets could be precisely controlled in the range 50 µm-200 µm by varying the flow rates of the dispersed and continuous phases. Consequently, alginate concentration and microparticle size were shown to influence the phage release profile and the degree of acid protection afforded to phages upon exposure to simulated gastric fluid (SGF). Bigger microparticles (∼100 µm) showed better acid protection compared with smaller beads (∼50 µm) made from the same formulation. Increasing the alginate composition resulted in improved acid protection of phages for similar particle sizes. The high viscosity formulations containing higher amounts of alginate (e.g. 2% (w/v)) negatively affected ease of droplet generation in the microfluidic device thereby posing a limitation in terms of process scale-up. Felix O1 encapsulated in the formulation containing 10% (w/v) ES100 and 1% (w/v) alginate showed excellent protection upon exposure of the gelled microparticles to SGF (pH 1 for 2 h) without the use of any antacids in the encapsulation matrix. Encapsulated phages previously exposed to SGF (pH 1 for 2 h) were released at elevated pH in simulated intestinal fluid (SIF) and were shown to arrest bacterial growth in the log growth phase. We have therefore demonstrated the microencapsulation of phages using readily available microfluidic chips to produce solid dosage microcapsule forms with a rapid pH triggered release profile suitable for targeted delivery and controlled release in the gastrointestinal tract.

Applying multi-criteria analysis for preliminary assessment of the properties of alginate immobilized Myriophyllum spicatum in lake water samples.

The preliminary assessment of the properties of alginate immobilized aquatic weed Myriophyllum spicatum beads-MsAlg in a multi-element system of nine Serbian lakes water samples was done. Herein, the results obtained in the biosorption experiment with MsAlg contents of twenty-two elements analysed by inductively coupled plasma-optical emission spectrometry, biosorption capacity, element removal efficiency, total hardness (TH) and quality index of water (WQI) are presented. Scanning electron microscopy with energy dispersive X-ray spectroscopy was used for the characterization of M. spicatum and its beads. The study showed that aluminium, magnesium and strontium were adsorbed by MsAlg in the water samples from all examined lakes; barium and iron in the water samples from six lakes. The overall average efficiency of MsAlg in biosorption of elements was in the following order: Al > Ba > Sr > Fe > Mg (58.6, 51.7, 48.2, 23.9 and 17.7%, respectively). The increase of TH and WQI values after the biosorption was noticed in all studied lake water samples. The most significant correlations for pH were regarding the contents of B, Mg and Ca, whereas WQI was highly correlated to the contents of B and Mg, and pH. The complexity of the obtained data was explained by Cluster Analysis and Principal Component Analysis, which showed good discrimination capabilities between the water samples taken from different locations. Considering that the invasive M. spicatum is natural, widespread and that its immobilization is cheap and eco-friendly, presented findings could be helpful in further assessment of MsAlg beads for its potential use as biofilter.

Preparation and characterization of new low cost adsorbent beads based on activated bentonite encapsulated with calcium alginate for removal of 2,4-dichlorophenol from aqueous medium.

This study explored the potential of composites organo-bentonite/alginate beads as adsorbents for the removal of 2,4-dichlorophenol (2,4DCP) from aqueous solution. Bentonite was firstly modified with cationic surfactants octadecyltrimethylammonium, hexadecyl trimethylammonium and phenyltrimethylammonium, then encapsulated with calcium alginate to form adsorbent composite beads. X-ray diffraction was used to study the change in the structural properties of the samples. The intercalated cationic surfactants were characterized by Fourier transform infrared spectroscopy (FTIR). The adsorption was studied using various operating parameters such as contact time, temperature, pH and initial 2,4DCP concentration. The results showed that the amount of 2,4DCP increased with increasing initial concentration, contact time and temperature indicating that the adsorption process of 2,4DCP onto composites is endothermic. Adsorption of 2,4DCP followed pseudo-second-order kinetics. The Langmuir isotherm model fitted well the isotherm data, indicating a monolayer homogeneous adsorption. The prepared adsorbents exhibited relatively high adsorption capacity of 142 to 391 mg/g founded by this model.

A phase I/II randomized, controlled, clinical trial for assessment of the efficacy and safety of ß-D-mannuronic acid in rheumatoid arthritis patients.

BACKGROUND: Following the potent efficacy of ß-D-mannuronic acid (M2000) in phase I/II trial in ankylosing spondylitis patients, the present clinical trial was conducted to evaluate the efficacy, safety, and tolerability of this novel drug in rheumatoid arthritis (RA) patients who had inadequate response to conventional therapy. METHOD: The study was a 12-week randomized, controlled, phase I/II clinical trial with two treatment arms: M2000 and conventional treatment. Patients who had RA according to the modified American College of Rheumatology (ACR) criteria, with active disease at baseline also inadequate response to conventional therapy, were enrolled in this study. M2000 was administrated at a dose of two capsules (500 mg) per day orally during a period of 12 weeks. The primary endpoint was the proportion of patients fulfilling the ACR 20% improvement criteria after 12 weeks of M2000 therapy. Moreover, the patients were also followed up for safety. RESULTS: There were no statistically significant differences between treatment and conventional groups at baseline characteristics. The ACR20 response rate was significantly higher among M2000-treated patients than conventional-treated control, so that 74% of patients in treatment group showed an ACR20 response after 12 weeks of M2000 therapy (74 versus 16%; P = 0.011). 10% of M2000-treated patients and 57.1% of conventional-treated patient's adverse events occurred during this study. CONCLUSION: Treatment with M2000 in combination with conventional therapy showed a significantly superior efficacy along with a high safety profile compared to conventional-treated patients. Thereby, M2000 might be suggested as a suitable option in the treatment of RA.

Seasonal biomass and alginate stock assessment of three abundant genera of brown macroalgae using multispectral high resolution satellite remote sensing: A case study at Ekas Bay (Lombok, Indonesia).

The potential of Indonesian bays as alginate producers was assessed by determining the stock of wild brown algae and exploring their biomass as alginophytes at the scale of entire bay, using a combination of field observations, remote sensing high resolution data and GIS tools. Ekas Bay in Lombok Island presented a stock of brown macroalgae which varied with season and species: for Padina the biomass reached 97.85±12.63 and 79.54±2.53tons in May/June and November respectively; for Sargassaceae species, it reached 669.70±109.64 and 147.70±77.97tons in May/June and November respectively. The best alginate yields occurred during the May/June period: Padina could produce 9.10±0.06tons DW of alginates. Interestingly, Sargassum/Turbinaria together allow 207.61±0.42tons DW of alginates. This study suggests that wild Sargassaceae represent an interesting stock in terms of biomass, alginate yield and M/G ratio.

In vitro and in vivo toxicity assessment of alginate/eudragit S 100-enclosed chitosan-calcium phosphate-loaded iron saturated bovine lactoferrin nanocapsules (Fe-bLf NCs).

Lactoferrin has been known to have antimicrobial properties. This research was conducted to investigate the toxicity of Alginate/EUDRAGIT® S 100-enclosed chitosan-calcium phosphate-loaded Fe-bLf nanocapsules (NCs) by in vitro and in vivo assays. Brine shrimp lethality assay showed that the LC50 value of NCs was more than 1mg/mL which indicated that NCs was not toxic to Brine shrimp. However, the LC50 values for the positive control potassium dichromate at 24h is 64.15µg/mL, which was demostrated the toxic effect against the brine shrimp. MTT cytotoxicity assay also revealed that NCs was not toxic against non-cancerous Vero cell line with IC50 values of 536µg/mL. Genotoxicity studies by comet assay on Vero cells revealed that NCs exerted no significant genotoxic at 100µg/mL without tail or shorter comet tail. Allium cepa root assay carried out at 125, 250, 500 and 1000µg/mL for 24h revealed that the NCs was destitute of significant genotoxic effect under experimental conditions. The results show that there is no significant difference (p>0.05) in mitotic index between the deionized water and NCs treated Allium cepa root tip cells. In conclusion, no toxicity was observed in NCs in this study. Therefore, nontoxic NCs has the good potential to develop as a therapeutic agent.

Chemical and toxicological assessment of arsenic sorption onto Fe-sericite composite powder and beads.

Batch sorption and leaching of arsenic (1-30mgL-1) on Fe-sericite composite powder and beads were investigated in this study. Fe-sericite composite powder was made from natural sericite modified with iron, and alginate was used to transform the powder into beads. The maximum sorption capacities of the Fe-sericite composite powder (15.04 and 13.21mgg-1 for As(III) and As(V), respectively) were higher than those of the corresponding beads (9.02 and 7.11mgg-1 for As(III) and As(V), respectively) owing to the higher specific surface area of the powder. In addition, the leaching amounts of As(III) from Fe-sericite composite beads (≤ 15.03%) were higher than those of the corresponding powder (≤ 5.71%). However, acute toxicity of As(III)-sorbed Fe-sericite composite beads toward Daphnia magna was not significantly different from that of the corresponding powder (p > 0.05). Considering higher uptake of the powder particles by the daphnids, Fe-sericite composite beads seem to be a more appropriate and safer sorbent for arsenic removal in practical application. Based on Fe content, Fe-sericite composite beads had similar or higher maximum sorption capacities (71.19 and 56.11mgg-1 Fe for As(III) and As(V), respectively) than those of previously reported sorbents.

Assessment of different systems for the production of aldonic acids and sorbitol by calcium alginate-immobilized Zymomonas mobilis cells.

Equimolar amounts of lactobionic acid and sorbitol may be obtained in a reaction catalyzed by the enzymes glucose-fructose oxidoreductase and glucono-δ-lactonase, which are found in the periplasm of Zymomonas mobilis. These reactions are generally conducted using immobilized bacterial cells, and the cell treatment and immobilization steps are costly and time-consuming. This study evaluated alternatives to simplify the preparation of calcium alginate-immobilized biocatalyst and its application in different operation modes and types of reactors. It was possible to eliminate cell permeabilization with cetyltrimethylammonium bromide, and the reticulation of Z. mobilis cells with glutaraldehyde sufficed to inhibit the fermentative metabolism of carbohydrates by the bacterium, with accumulation of bioconversion products. When the process was carried out in a mechanically stirred reactor in batch mode, 530 mmol L- 1 of products were obtained in 24 h. The process was also tested in fed-batch mode so as to use of a larger amount of lactose, since it could not be used in the batch because of its low solubility in water. Under this condition, final products concentration reached 745 mmol L- 1 within 42 h. Similar results were obtained for reactions conducted in a pneumatically stirred reactor in batch and fed-batch modes, proving the potential use of this process in several industrial settings.

Assessment of Influence of Contact Time between Alginate and Type III Dental Stone on Properties of Cast Model: An in vitro Study.

INTRODUCTION: Alginate is a versatile, irreversible hydrocolloid impression material, which is cost-effective and forms an essential component in dental practice. For elevating the hardness of the cast models, hardeners are combined with stone. Hence, we planned the present study to evaluate the impact of altering the time of contact between alginate and stone after various interim periods. MATERIALS AND METHODS: The present study included the assessment of impact of time of contact between alginate and stone by the construction of 90 casts using a cylinder model. Two bisecting lines were marked and were named as y and y'. These lines were used for testing the dimensional stability. Using chemically cured acrylic resin, the construction of ten special trays was done. All the impression casts were randomly divided into two study groups, with 45 casts in each group-group I: control group, casts were removed after 60 minutes; group II: study group, casts were removed after 9 hours. A digital caliper was used for measuring the dimensional stability of the cast. All the data were collected and analyzed. RESULTS: In the specimens of the control group (group I) and the study group (group II), the mean dimensions from y to y' were found to be 17.54 and 17.95 respectively. The mean reading of hardness in the control group and study group was found to be 0.59 and 0.20 respectively. In groups I and II, the number of specimens showing clarity of two lines (X and X") was 0 and 5 respectively. CONCLUSION: There was no change in the dimensional stability of the dental stone model when the contact time was increased. CLINICAL SIGNIFICANCE: Within certain limits, the contact time between alginate and stone can be altered without significantly altering the properties of the cast.

Reactogenicity and safety assessment of an attenuated nanovaccine against scorpion envenomation: Preclinical study.

An attenuated nanovaccine (Nps - V∗) has been developed to protect humans from fatal scorpion envenomation in at-risk regions. This study was conducted to evaluate the toxicity and the local reactogenicity of the Nps - V∗ nanovaccine developed against Androctonus australis hector (Aah) venom. Assessment of the systemic inflammatory response and serum cytokine levels were evaluated in vaccinated mice with 100µg of irradiated Aah venom (V∗) encapsulated or not into polymeric calcium-alginate nanoparticles (Nps) and injected by subcutaneous (s.c) route. The local reactogenicity was evaluated by dermal Draize observations and skin tissue analysis at the injection site of vaccinated rabbits with 250 or 500µg of V∗-loaded into Nps. All animals gained weight and had normal food consumption during the study. Additionally, results showed that the nanoformulation Nps - V∗ did not cause clinical evidence of systemic toxicity in mice or rabbits, a transient edema/erythema at the injection site was only recorded as treatment-related reactogenicity. These results indicated a favorable safety profile for Nps - V∗ and supported its use in superior animal tests, then in a Phase 1 clinical trial.

A Randomized Controlled Trial on the Outcome in Comparing an Alginate Silver Dressing With a Conventional Treatment of a Necrotizing Fasciitis Wound.

Necrotizing fasciitis (NF) is a high morbidity and mortality disease and also demands high economic resources. The standard treatment of NF is surgical debridement and proper dressing for wound bed preparation. The efficacy of silver alginate dressing can inhibit the growth of microorganisms and keep the environment clean for wound bed preparation. However an optimal dressing to manage such wounds has yet to emerge. NF patients who were admitted between April 2013 and May 2016 were randomized to have wound dressing using either silver dressing (Ag group) or normal saline solution gauze (NSS group). The 4 main outcomes for comparison between the 2 groups were the duration of wound bed preparation, total cost during hospital stay, the duration of hospital stay, and the pain score. Thirty-nine patients were included in the study: 19 patients in the NSS group and 20 patients in the Ag group. The mean duration of wound bed preparation in the NSS group was 31.87 days, and in Ag group it was 21.39 days, but this trend was not statistically significant ( P = .057). The mean cost of treatment in the NSS and Ag groups was not significantly different ( P = .434; US$3308.83 and US$2647.82, respectively). The duration of hospital days in the 2 groups was not significantly different either (29.19 days [NSS group] and 20.99 days [Ag group]; P = .222). The pain score was significantly lower in the Ag group than those in the NSS group. Although silver dressing seems to be expensive, the cost of total treatment during hospital stay and the duration of hospital stay were not significantly different between groups. However, the mean duration of wound bed preparation seems to trend favoring toward the silver dressing group.

Bioprinting Pattern-Dependent Electrical/Mechanical Behavior of Cardiac Alginate Implants: Characterization and Ex Vivo Phase-Contrast Microtomography Assessment.

Three-dimensional (3D)-bioprinting techniques may be used to modulate electrical/mechanical properties and porosity of hydrogel constructs for fabrication of suitable cardiac implants. Notably, characterization of these properties after implantation remains a challenge, raising the need for the development of novel quantitative imaging techniques for monitoring hydrogel implant behavior in situ. This study aims at (i) assessing the influence of hydrogel bioprinting patterns on electrical/mechanical behavior of cardiac implants based on a 3D-printing technique and (ii) investigating the potential of synchrotron X-ray phase-contrast imaging computed tomography (PCI-CT) for estimating elastic modulus/impedance/porosity and microstructural features of 3D-printed cardiac implants in situ via an ex vivo study. Alginate laden with human coronary artery endothelial cells was bioprinted layer by layer, forming cardiac constructs with varying architectures. The elastic modulus, impedance, porosity, and other structural features, along with the cell viability and degradation of printed implants were examined in vitro over 25 days. Two selected cardiac constructs were surgically implanted onto the myocardium of rats and 10 days later, the rat hearts with implants were imaged ex vivo by means of PCI-CT at varying X-ray energies and CT-scan times. The elastic modulus/impedance, porosity, and structural features of the implant were inferred from the PCI-CT images by using statistical models and compared with measured values. The printing patterns had significant effects on implant porosity, elastic modulus, and impedance. A particular 3D-printing pattern with an interstrand distance of 900 µm and strand alignment angle of 0/45/90/135° provided relatively higher stiffness and electrical conductivity with a suitable porosity, maintaining high cell viability over 7 days. The X-ray photon energy of 30-33 keV utilizing a CT-scan time of 1-1.2 h resulted in a low-dose PCI-CT, which provided a good visibility of the low-X-ray absorbent alginate implants. After 10 days postimplantation, the PCI-CT provided a reasonably accurate estimation of implant strand thickness and alignment, pore size and interconnectivity, porosity, elastic modulus, and impedance, which were consistent with our measurements. Findings from this study suggest that 3D-printing patterns can be used to modulate electrical/mechanical behavior of alginate implants, and PCI-CT can be potentially used as a 3D quantitative imaging tool for assessing structural and electrical/mechanical behavior of hydrogel cardiac implants in small animal models.

Immobilization of ammonia-oxidizing bacteria by polyvinyl alcohol and sodium alginate

Abstract Ammonia-oxidizing bacteria were immobilized by polyvinyl alcohol (PVA) and sodium alginate. The immobilization conditions and ammonia oxidation ability of the immobilized bacteria were investigated. The following immobilization conditions were observed to be optimal: PVA, 12%; sodium alginate, 1.1%; calcium chloride, 1.0%; inoculum concentration, 1.3 immobilized balls/mL of immobilized medium; pH, 10; and temperature, 30 °C. The immobilized ammonia-oxidizing bacteria exhibited strong ammonia oxidation ability even after being recycled four times. The ammonia nitrogen removal rate of the immobilized ammonia-oxidizing bacteria reached 90.30% under the optimal immobilization conditions. When compared with ammonia-oxidizing bacteria immobilized by sodium alginate alone, the bacteria immobilized by PVA and sodium alginate were superior with respect to pH resistance, the number of reuses, material cost, heat resistance, and ammonia oxidation ability.

Preparation and in vitro assessment of wet-spun gemcitabine-loaded polymeric fibers: Towards localized drug delivery for the treatment of pancreatic cancer.

BACKGROUND/OBJECTIVES: There has been minimal improvement in the prognosis of pancreatic cancer cases in the past 3 decades highlighting the crucial need for more effective therapeutic approaches. A drug delivery system capable of locally delivering high concentrations of chemotherapeutics directly at the site of the tumor is clearly required. The aim of this study was to fabricate and characterize the biophysical properties of gemcitabine-eluting wet-spun polymeric fibers for localized drug delivery applications. METHODS/RESULTS: Fibers spun from alginate or chitosan solutions with or without the anticancer drug gemcitabine had a uniform surface area, were internally homogeneous and ranged from 50-120 µm in diameter. Drug encapsulation ranged from 13-52%, depending on the type and concentration of polymer used. Gemcitabine displayed first-order release kinetics where 64-82% of the loaded drug was rapidly released within the first 10 h followed by a sustained release over the next 134 h. A time dependent inhibition of ex vivo tumor spheroid growth and cell viability was observed after incubation with gemcitabine-loaded fibers but not control fibers. CONCLUSION: With further development these studies could lead to the manufacture of a safe and effective delivery system designed to combat non-resectable pancreatic cancer for which currently there is minimal chance of cure.