Development of chitosan-coated agar-gelatin particles for probiotic delivery and targeted release in the gastrointestinal tract.

This study reports the development of a novel and simple formulation for probiotic delivery using chitosan-coated agar-gelatin gel particles. This methodology involves the production of agar-gelatin particles by thermally treating a mixture of agar and gelatin solutions at high temperatures (121 °C) and subsequently coating with chitosan. The particles were able to protect the probiotic strain Lactobacillus plantarum NCIMB 8826 during incubation for 2 h in simulated gastric fluid (pH 2), as no statistically significant loss (P > 0.05) in cell concentration was observed, and also resist dissolution in simulated intestinal fluid (pH 7.2). Interestingly, this protection is related to the fact that the intense thermal treatment affected the physicochemical properties of agars and resulted in the formation of a strong and tight polymer network, as indicated by the X-ray diffraction (XRD) analysis. Using an in vitro faecal batch fermentation model simulating the conditions of the distal part of the large intestine (pH 6.7-6.9), it was demonstrated by quantitative real-time PCR that the majority of L. plantarum cells were released from the agar-gelatin particles within 30 to 48 h. Overall, this work led to the development of a novel methodology for the production of probiotic-containing particles, which is simpler compared with current encapsulation technologies and has a lot of potential to be used for the controlled release of probiotics and potentially other solid bioactives in the large intestine.Key Points• Chitosan gel particles is a simple and scalable method of probiotic encapsulation.• Autoclaving agar-gelatin particles increases their stability at low pH.• Chitosan gel particles protected L. plantarum during gastrointestinal conditions.• Probiotics could be controlled release in the colon using chitosan gel particles.

The effect of agar jelly on energy expenditure, appetite, gastric emptying and glycaemic response.

BACKGROUND AND PURPOSE: Agar contains a high amount of soluble fibre and has been shown to delay gastric emptying (GE) without impacting on glycaemic response (GR). The current study aimed to further the limited data on the effect of agar on metabolism by assessing the effects on GE and GR as well as appetite- and diet-induced thermogenesis (DIT). METHODS: In this randomized control trial, eleven healthy volunteers were tested on two occasions following an overnight fast. Following baseline and resting measurements, volunteers were either fed a fruit-flavoured drink (liquid) or consumed a fruit-flavoured jelly (jelly). The two were exactly the same in composition except the jelly contained 4 g of agar crystals. Both contained 50 g of available carbohydrate. DIT was measured using indirect calorimetry, GE using the (13)C sodium acetate breath test, appetite using visual analogue scale and GR using finger prick blood samples. RESULTS: The jelly significantly delayed GE across all time points-latency phase (p = 0.07), lag phase (p = 0.04), half-time (p < 0.0001), ascension time (p = 0.025). The jelly also increased all appetite parameters-hunger (p = 0.006), fullness (p = 0.035), desire to eat (p = 0.03) and prospective consumption (p = 0.011). However, there were no significant differences in either GR or postprandial DIT between the liquid and jelly. CONCLUSION: Agar delays GE and increases appetite but does not change GR or DIT most probably due to the increase in viscosity caused by the agar jelly.

Seaweed polysaccharide derived bioaldehyde nanocomposite: Potential application in anticancer therapeutics.

In the present study, we have demonstrated synthesis of agar aldehyde (Aald) from seaweed polysaccharide and its further successful application for preparation of Aald mediated solid silver nanocomposite (Aald-AgNPs). Aald-AgNPs were characterized for biophysical properties by FTIR, XRD, SEM, TEM, XPS, and UV-vis spectroscopy. Aald-AgNPs were further tested in vitro and in vivo for anticancer activity. The results of the in vitro study revealed that Aald-AgNPs exhibited activity against 3 cancer cell lines. Aald-AgNPs were found to act through causing dose dependent increase in cell size, inducing anueploidy, mitochondrial disintegration and increasing septa formation in cell cytoplasm. Results of in vivo anticancer activity against ME-180, Colon-26, and HL-60 xenograft mice tumor models showed 64 %, 27.3 % and 51 % reduction in tumor volume, respectively with 83-100 % survival rate. Aald-AgNPs exhibited excellent antibacterial activity. It was interesting to note that Aald-AgNPs did not exhibit any significant detrimental effect on viability and metabolic activity of normal bone marrow derived mesenchymal stem cells. This study opens new areas of research for chemists and biologists to use seaweed-derived polymers to develop nanocomposites for cancer therapeutics.

A multifunctional metal-biopolymer coordinated double network hydrogel combined with multi-stimulus responsiveness, self-healing, shape memory and antibacterial properties.

Outfitted with abundant hydrogen bonding and coordination active groups, carboxymethyl chitosan (CMC) possesses a class of naturally occurring ligands for coordination with metal ions, establishing its excellent potential for various fields. Herein, by incorporating the naturally derived CMC into a thermally reconfigurable agarose (Agar) gel medium, a novel type of metal-biopolymer coordinated double network hydrogel (DN gel) was successfully fabricated via the strong coordination interactions. The interpenetrated CMC was confirmed to retain its excellent chelating abilities within the bulk gel matrix, which resulted in a series of metal-coordinated DN gels through spontaneous self-associative complexation with metal ions such as Cu2+, Zn2+, Ni2+, Co2+, Fe3+, and Cr3+. Moreover, these two types of physical cross-links are functionally independent and reversible, which enables the programming of the hydrogel with multi-functionality, including pH-regulated shape memory behavior, multi-staged self-healing properties and durable antibacterial activities. Thus, we believe that the successful preparation of such a coordination-driven DN gel will lead to the development of biopolymer-based multifunctional hydrogels, as well as provide new insight into nanocomponent assembly and soft electronic biosensing systems for biomedical applications.

Agar/κ-carrageenan/montmorillonite nanocomposite hydrogels for wound dressing applications.

In this study, agar/κ-carrageenan/montmorillonite (MMT) hydrogels were prepared to examine their usability as wound dressing materials and to see the effect of MMT amount on some properties of agar/κ-carrageenan hydrogel materials. Hydrogels were characterized by SEM-EDX, TEM and DSC analyses. By increasing the MMT content within hydrogel matrix from 0% to 5%, the decomposition temperature of the hydrogel material was increased from 256.6 °C to 262.1 °C. Swelling amount of hydrogels in d-glucose solution (2682%) was found to be much higher compared with other physiological solutions such as physiological saline solution (937%), synthetic urine solution (746%) and simulated wound fluid (563%). The release studies of analgesic lidocaine hydrochloride (LDC) and antibiotic chloramphenicol (CLP) drugs from hydrogel systems demonstrated that the release amount of LDC and CLP from hydrogels could be controlled by MMT amount within hydrogel matrix. The concentrations of drugs within hydrogel sample stored at 4 °C for 6 months did not exhibit a significant change. Hydrogel materials containing CLP exhibited good antibacterial activity against E. coli and S. aureus. Cytotoxicity test results indicated that hydrogels were biocompatible with MG-63 cells. The ultimate compressive stress of agar/κ-carrageenan hydrogel with LDC and CLP and agar/κ-carrageenan/MMT hydrogel including 5% MMT with LDC and CLP was measured as 38.30 kPa and 47.70 kPa, respectively. The experimental results revealed that prepared agar/κ-carrageenan and agar/κ-carrageenan/MMT hydrogels have great potential for wound care applications.

Rapid and non-invasive detection and imaging of the hydrocolloid-injected prawns with low-field NMR and MRI.

Method development for monitoring economically motivated food adulteration is pivotal for preventing health problems caused by illegal food additives. In this work, low-field nuclear magnetic resonance (LF-NMR) spectroscopy and magnetic resonance imaging (MRI) was applied for the detection and mapping of adulterated prawns injected with different hydrocolloids including gelatin, carrageenan, agar, amorophophallus konjac and xanthan gum. The characteristic T2 fitting curves were obtained which can be used to tell apart adulterated prawns from normal ones. Furthermore, the benefit from high quality LF-MRI images showed the major accumulation site of the hydrocolloids injected in prawn. The location of these injections was mainly confined to well resolved accumulation in brain region and three following subtle sites: back, tail and claws. Different hydrocolloids can be successfully distinguished in adulterated prawns with principal component analysis. Therefore, rapid, non-invasive and low-cost LF-NMR technique offers a powerful tool for the identification of hydrocolloids adulteration in real-time.

Superiority of oral agar and phototherapy combination in the treatment of neonatal hyperbilirubinemia.

OBJECTIVE: To determine the value of oral agar in the treatment of neonatal hyperbilirubinemia and to compare it with two other treatment modalities: phototherapy alone and phototherapy plus oral agar. METHODS: Two hundred eight jaundiced full-term newborns were divided into four groups. They were given either phototherapy alone, phototherapy plus oral agar, oral agar alone, or no treatment (control group). The changes in the serum bilirubin values were determined and the results were compared statistically, mainly using analysis of variance. RESULTS: In all three therapy groups, the time required to reduce the bilirubin level to either 15 mg/dL or to 10 mg/dL was significantly shorter than that required by the control group. Although oral agar was found to be as effective as phototherapy, the most significant decrease in bilirubin level was in the combination group. CONCLUSIONS: The efficacy of phototherapy in decreasing the serum bilirubin level in neonatal hyperbilirubinemia can be augmented with the use of oral agar. Oral agar can also be used as a single agent for the treatment of neonatal hyperbilirubinemia, since it is as effective as phototherapy.

Macroscopic enzyme-mapping verification of large, homogeneous, experimental myocardial infarcts of predictable size and location in dogs.

Difficulty is frequently experienced in producing a large homogeneous myocardial infarct in the dog heart because of the extensive network of coronary anastomoses. This problem may be overcome by combining the ligation of the left anterior descending coronary artery with agar injection into the distal coronary vasculature to obliterate anastomotic channels. All infarcts produced in this manner occupied a constant area in the anterior wall of the left ventricle. From our results in 25 dogs, the individual infarct averaged 12.3 Gm. in weight (range 9.4 to 13.5), representing 25 to 30 per cent of the total left ventricular muscle mass. The homogeneity of the infarct was verified by a simple, macroscopic enzyme-mapping technique based on the inability of the ischemic (dehydrogenase-deficient) myocardium to reduce triphenyl tetrazolium chloride and by detailed histologic studies. Apart from providing ample raw material for comprehensive morphologic, chemical, histochemical, and radioisotopic analyses, a large myocardial infarct also serves as a useful experimental model for various physiological and hemodynamic studies of cardiogenic shock and left ventricular akinesis.

Induction of experimental chronic Pseudomonas aeruginosa lung infection with P. aeruginosa entrapped in alginate microspheres.

Alginate-producing, mucoid P. aeruginosa is frequently found in the lungs of patients with cystic fibrosis (CF), where it causes a chronic infection. The importance of alginate in the pathogenesis was demonstrated by the ability to establish chronic P. aeruginosa lung infection in rats if P. aeruginosa entrapped in minute alginate-beads were inoculated transtracheally. Alginate beads containing P. aeruginosa were formed by nebulizing a suspension of seaweed sodium-alginate and P. aeruginosa into a calcium solution. The alginate bead method of establishing infection was compared to an agar-bead method and proved to be quantitatively similar after 4 weeks. The ability of the two methods to induce formation of precipitins, IgA and IgG antibodies against P. aeruginosa antigens, including outer membrane proteins, flagella, exoenzymes and alginate, was assessed by crossed immunoelectrophoresis, enzyme-linked immunosorbent assay and immunoblotting. The two methods of inducing infection were comparable and infected rats had significantly higher antibody response than rats inoculated with sterile beads. We suggest that the alginate bead model closely resembles the later stages of CF-lung infection and that it offers the theoretical advantage of using a substance which is chemically similar to the alginate produced in vivo by P. aeruginosa.

A histological study of the use of agar as a delivery vehicle for alcohol or iron to rats.

The supply of ethanol and other substances to the rat has necessitated the development of quite complex dietary preparation and feeding techniques. This study reports the use of ethanol/water solutions in conjunction with normal rat chow diet to provide up to 30 g/kg/day ethanol to study animals. By additionally supplying agar gels containing ethanol, voluntary intake of ethanol was raised to a possible maximum of 48 g/kg/day. Hepatic steatosis was produced in 7/18 rats supplied ethanol in this fashion. Agar gels were also used to provide carbonyl iron to rats and it produced grade 3 to 4 hepatocyte iron loading in all study animals. The study demonstrates a practical method for administering ethanol and iron to rats without altering normal dietary intake. Ethanol supplied in this way does produce hepatic injury in the rat.

Effects of cellulose, agar and their mixture on colonic mucin degradation in rats.

A feeding study was conducted to elucidate the role of two different fibers, cellulose and agar, and mixture of the two fibers on fecal mucinase activity in rats. Fiber-free basal control diet was mixed with either 15% cellulose, 15% agar or half cellulose (7.5%) and half agar (7.5%). These diets were fed for 5 weeks to groups of 6 male Sprague-Dawley rats. Mucinase activity was assayed in fresh rat feces. Body weight gain of rats fed different diet groups did not show significant difference (p greater than 0.05). Specific and total mucinase activity was highest in rats fed fiber-free control diet and 15% agar diet, intermediate in rats fed the fiber mixture group and lowest in rats fed 15% cellulose diet. The differences among the three groups were significant (p less than 0.05).

Comparison of hypolipidemic effect of refined konjac meal with several common dietary fibers and their mechanisms of action.

The effects of RKM in comparison with pectin, algin and agar on lipid levels in serum and liver and on liver histopathology in rats were studied. In addition, the effects of all the tested materials on the composition and output of fecal bile acid were observed. All four kinds of dietary fiber were given at a level of 5% of diet to young male rats of Wistar strain fed on a lipid-rich diet containing 5% lard, 1% cholesterol and 0.25% cholate. All the dietary fibers tested have similar effects on serum lipid composition. In all groups, these substances prevented increases in total cholesterol in fasting serum, but the level of triglyceride was unchanged. The concentrations of total cholesterol and triglyceride in the liver were lower in the RKM group than in the control group and the other three groups. Hepatic histopathological examination also showed the most significant lipotropic effect in the RKM group. The daily output of fecal bile acids (CDCA + GDCA) was significantly increased in the four experimental groups than in the normal group and the control group. The increase of CDCA was more significant than GDCA, suggesting that the increase of fecal bile acids, especially CDCA, may be one of the mechanisms by which RKM and the other three dietary fibers exerts a hypocholesterolemic effect.

Use of agar-based diet to fulfil the food and water requirements of mice.

Mice were fed an agar-based diet without an additional source of water for 5 weeks. In comparison with a similar group of mice fed a commercial diet and water ad libitum, there were no significant changes in bodyweight.

[Clinical evaluation of hydrogel-type dressing materials after their 8-year use]. / Kliniczna ocena hydrozelowych materialów opatrunkowych po 8-letnim ich zastosowaniu.

The subject to assessment were hydrogel dressings (in 42 patients) compared with the classical gauze dressing with an addition of various pharmaceuticals (in 65 patients). We found out that the gauze dressings get dry 24 hours after they have been applied, their replacement being very painful. The hydrogel dressings, on the other hand, do not cause any pain when replaced after the 24 hours. The hygroscopic properties of hydrogel dressings allow a quick cleaning of the wound from microorganisms. Permitting an easy absorption of antibiotics and other drugs, they contribute to an acceleration of the healing process and epidermis development.

[Experimental studies of new Polish hydrogel dressing materials HDR]. / Badania doswiadczalne nowych polskich opatrunków hydrozelowych o symbolu HDR.

Recently the spectrum of dressings was enriched, incorporating the so-called hydrogel dressing, made by Geistlich Sons Ltd. and Byk Goldbin-Konstanz referred to as "Geliperm". In Poland, HDR hydrogel dressings' technology was launched by Institute of Radiative Technology, Lódz+ Polytechnic. This type of dressing is obtained by radiative cross-linking of hydrophilic polymers. The experimental studies of the new Polish hydrogel materials were accomplished at the Department of Experimental Surgery and Biomaterials Research, the Chair of traumatologic Surgery, Medical Academy of Wroclaw. These studies concerned three kinds of hydrogel dressings, different in composition and irradiation conditions. HDR-1 10% of polyvinylpyrrolidone+, 1.5% of agar, 1.5% of polyethylene glycol 300, irradiated with 30 kGy (gamma radiation of 60Co); HDR-1 with neomycin--formula as above plus neomycin sulfate (2.5%); HDR-2 6% of polyvinylpyrrolidone++, 1% of agar, 1.5% of polyethylene glycol 300, irradiated with 25-27 kGy (gamma radiation of 60Co). The usable properties of the HDR dressings approximate those of the West German products. Owing to the lab tests, biological and in vitro examinations we had performed, it was possible to state that aqueous extracts of the hydrogel dressings subjected to assessment did'nt exhibit hemolytical or toxic activities in cellular tests, at the same time lacking an irritating effect. They cause a minimal tissular reaction and accelerate the process of healing.

[Characteristics of diffusion of polyene antibiotic levorin]. / Osobennosti diffuzii polienovogo antibiotika levorina.

Studies were performed which provided estimation of the impact of some physico-chemical properties of levorin, a polyene antibiotic, and in particular its multicomponent nature and capacity for isomerization on formation of inhibition zones in assay of the antibiotic activity by the agar diffusion method. It was shown that the levorin complex components markedly differed in the biological activity and diffusion capacity. The diffusive properties of the highly active components A2 and A3 were better. The diffusion rate of isomerized levorin was much lower than that of the initial levorin. To provide better diffusion of the levorin components with low diffusion capacity it was recommended to use a new solution composed of ethanol, glycerol and water at a ratio of 15:25:60.

[Determining the sensitivity of Pseudomonas to chemotherapeutic preparations by the micromethod in liquid synthetic medium]. / Opredelenie chuvstvite'lnosti pseudomonad k khimioterapevti- cheskim preparatam mikrometodom v zhidkoi sinteticheskoi srede.

Ever increasing interest is being displayed lately to simple, economic and standard systems for assay of antibiotic sensitivity of microbes with microtechniques in nutrient media requiring no raw materials in short supply. For determining sensitivity of Pseudomonas spp. to chemotherapeutics a liquid synthetic medium balanced by its cationic composition and containing no competing agents of sulfanylamides was used. Three procedures were comparatively estimated: the method of serial dilutions in the liquid medium with using immunological trays, the method of serial dilutions in agar and the diffusion test. In the estimation 185 strains of various Pseudomonas species were used: P. aeruginosa, P. cepacia, P. fluorescens, P. stutzeri, P. putida and P. pseudomallei. The method using the liquid synthetic medium and trays provided more precise interpretation of the results of the assay of the Pseudomonas spp. sensitivity to aminoglycosides, tetracycline, polymyxin and sulfamonomethoxine that the routine procedures. It showed some other advantages such as simplicity, low cost, low medium requirement and glassware economy. The application of the method allowed to exclude the use of expensive imported nutrient media in assay of sulfanylamide sensitivity.

Desenvolvimento de métodos microbiológicos rápidos (MMRs) para avaliação da potência de agentes antimicrobianos e suas incertezas de medição / Development of rapid microbiological methods (RMMs) for evaluation of potency of antimicrobial agents and their measurement uncertainties

O método de difusão em ágar tem sido utilizado na avaliação da atividade antimicrobiana desde a descoberta da penicilina. Apesar disso, pouco avanço ocorreu no sentido de reduzir o tempo necessário para a determinação dos halos de inibição de crescimento. O objetivo deste projeto foi desenvolver, otimizar e validar métodos microbiológicos rápidos (MMRs) para a avaliação da potência de agentes antimicrobianos, além de identificar, quantificar e avaliar as principais fontes de incerteza associadas à determinação da potência. O projeto foi dividido em quatro etapas: 1) influência da composição do meio de cultura na formação dos halos de inibição; 2) estudo da incerteza de medição associada à determinação da potência de agentes antimicrobianos; 3) desenvolvimento, otimização e validação de métodos microbiológicos rápidos (MMRs) para determinação da potência de agentes antimicrobianos e 4) determinação dos parâmetros envolvidos na formação dos halos de inibição de crescimento e estudo dos mecanismos de difusão e crescimento microbiano. Os resultados deste projeto possibilitaram a redução do tempo necessário para a determinação do tamanho dos halos de inibição. Adicionalmente, contribuiu com a elucidação dos mecanismos de difusão e crescimento microbiano, possibilitando identificar e quantificar as principais fontes de incerteza de medição associadas à formação dos halos de inibição

Agar diffusion method has been used in the evaluation of antimicrobial activity since the discovery of penicillin. Nevertheless, little progress has occurred in order to reduce the time required for the determination of growth inhibition zones. The goal of this project was to develop, optimize and validate rapid microbiological methods (RMMs) for evaluation of potency of antimicrobials, as well as to identify, quantify and assess the main sources of uncertainty associated with potency. The project was divided into four steps: 1) influence of culture medium composition on inhibition zones; 2) study of measurement uncertainty associated with antimicrobials potencies; 3) development, optimization and validation of rapid microbiological methods (RMMs) for the determination of antimicrobials potencies and 4) determination of the parameters involved in the formation of inhibition zones and study of mechanisms of diffusion and microbial growth. The results of this project allowed the reduction of the time required for the determination of inhibition zone sizes. Additionally, it contributed to the elucidation of the mechanisms of diffusion and microbial growth, making it possible to identify and quantify the main sources of measurement uncertainty associated with formation of inhibition zone sizes

Obstructing small bowel bezoars due to an agar diet: diagnosis using double balloon enteroscopy.

Primary small bowel bezoars are rare and may cause acute abdomen due to small bowel obstruction (SBO). A 70-year-old Japanese woman presented to the emergency room with abdominal pain, nausea and vomiting. The patient reported that she had eaten a large amount of highly-concentrated, agar dissolved in boiling water two days prior to presentation. Double balloon enteroscopy (DBE) revealed that white-colored, hard bezoars were clogged in the jejunum. At surgery, many bezoars were found impacted in the distal jejunum, and enterotomy was performed. The bezoars were elastic hard, crystallized objects. These bezoars were considered to have formed from highly-concentrated, dissolvable agar.