Special Issue: Biopolymers in Drug Delivery and Regenerative Medicine.

Biopolymers and biocomposites have emerged as promising pathways to develop novel materials and substrates for biomedical applications [...].

New Insights for Red Propolis of Alagoas-Chemical Constituents, Topical Membrane Formulations and Their Physicochemical and Biological Properties.

The main objectives of this study were to evaluate the chemical constitution and allergenic potential of red propolis extract (RPE). They were evaluated, using high performance liquid chromatography (HPLC) and the release of ß-hexosaminidase, respectively. A plethora of biologically active polyphenols and the absence of allergic responses were evinced. RPE inhibited the release of ß-hexosaminidase, suggesting that the extract does not stimulate allergic responses. Additionally, the physicochemical properties and antibacterial activity of hydrogel membranes loaded with RPE were analyzed. Bio-polymeric hydrogel membranes (M) were obtained using 5% carboxymethylcellulose (M1 and M2), 1.0% of citric acid (M3) and 10% RPE (for all). Their characterization was performed using thermal analysis, Fourier transform infrared (FTIR), total phenolic content, phenol release test and, antioxidant activity through 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and Ferric Reducing Antioxidant Power (FRAP). The latter appointed to the similar antioxidant capacity of the M1, M2 and M3. The degradation profiles showed higher thermostability to M3, followed by M2 and M1. The incorporation of RPE into the matrices and the crosslinking of M3 were evinced by FTIR. There were differences in the release of phenolic compounds, with a higher release related to M1 and lower in the strongly crosslinked M3. The degradation profiles showed higher thermostability to M3, followed by M2 and M1. The antibacterial activity of the membranes was determined using the disc diffusion assay, in comparison with controls, obtained in the same way, without RPE. The membranes elicited antibacterial activity against Staphylococcus aureus and Staphylococcus epidermidis, with superior performance over M3. The hydrogel membranes loaded with RPE promote a physical barrier against bacterial skin infections and may be applied in the wound healing process.

The biopolymer sugarcane as filling material of critical defects in rats.

PURPOSE: To evaluate the effects of particulate (granule-shaped) SCB on bone repair relating it to its biocompatibility and bone neoformation. METHODS: Thirty Wistar rats were submitted to a one 7-mm-diameter defect and divided equally into three experimental groups, with two different postoperative times of evaluation, 90 and 120 days. Each calvaria defect was filled up with clot (control group), particulated autogenous bone or granulated SCB. Five animals of each group were assessed at 90 and 120 days after surgery. In these two periods, histological and histometric analysis were obtained. RESULTS: The clot group showed a bone resorption trend while the autogenous bone group a bone repair trend. However in the SCB group, the critical defect filled up only with fibrous connective tissue and presented none bone neoformation. CONCLUSION: The sugarcane biopolymer when used in critical size defects was a biocompatible material and proved to be a good material to fill bone cavities, keeping them as uniform areas filled with soft tissue and avoiding the tissue shrinkage.

The biopolymer sugarcane as filling material of critical defects in rats

PURPOSE: To evaluate the effects of particulate (granule-shaped) SCB on bone repair relating it to its biocompatibility and bone neoformation. METHODS: Thirty Wistar rats were submitted to a one 7-mm-diameter defect and divided equally into three experimental groups, with two different postoperative times of evaluation, 90 and 120 days. Each calvaria defect was filled up with clot (control group), particulated autogenous bone or granulated SCB. Five animals of each group were assessed at 90 and 120 days after surgery. In these two periods, histological and histometric analysis were obtained. RESULTS: The clot group showed a bone resorption trend while the autogenous bone group a bone repair trend. However in the SCB group, the critical defect filled up only with fibrous connective tissue and presented none bone neoformation. CONCLUSION : The sugarcane biopolymer when used in critical size defects was a biocompatible material and proved to be a good material to fill bone cavities, keeping them as uniform areas filled with soft tissue and avoiding the tissue shrinkage.

Development of biopolymer nanocomposite for silver nanoparticles and Ciprofloxacin controlled release.

Screening of biopolymeric gel beads containing Silver NanoParticles (Ag-NPs) stabilized in Guar Gum Alkyl Amine (GGAA) and Ciprofloxacin (Cip) was carried out in order to obtain a novel nanocomposite with controlled release profile of both antimicrobians. The selected matrix composed of Alginate/High Methoxyl Pectin (HMP)/GGAA (4:4:1) was able to co-incorporate Ag-NPs and Cip with encapsulation efficiency higher than 70%. SEM images revealed good cohesivity and compatibility between the biopolymers and the cargos. Beads provided protection against Ag-NPs degradation at acidic pHs and HMP would played a key role providing hydrophobic regions. While Cip release profile showed a pH independent diffusional process, Ag-NPs release was restricted to matrix erodability. Calcium quelating agents and/or alginate degrading enzymes could modulate the release profile. The bactericidal activity of beads was tested in liquid medium, showing cooperative effects between the antimicrobials against Pseudomonas aeruginosa, Escherichia coli, Bacillus cereus and Staphylococcus aureus. TEM images confirmed interaction of Ag-NPs with bacterial surfaces followed by membrane damage. Results suggested the nanocomposite matrix as a promising system for oral treatment of intestinal infectious diseases caused by multidrug resistant and unknown microorganisms, since both Cip and Ag-NPs would be able to reach intestine in the active form.

Hydrogel of polysaccharide of sugarcane molasses as carrier of bone morphogenetic protein in the reconstruction of critical bone defects in rats.

PURPOSE: To evaluate the benefit of using carriers such as the biopolymer gel (hidrogel of polysaccharide of sugarcane molasses) associated with the bone morphogenetic proteins (BMP's) in the repair of critical bone defects in calvaria of Wistar rats. METHODS: Forty-two rats were submitted to a surgical calvaria bone defects. These animals were divided into two experimental groups, positive control group and negative control group. The Group I the calvaria defect was filled up with biopolymer gel, biological membrane, BMP and lyophilized graft. The Group II was treated with biopolymer gel, BMP and lyophilized graft. And the group III (positive control group) was treated with BMP, lyophilized graft and biological membrane. In the negative control group (Group IV) a defect was made in the rat calvaria and the animals were sacrificed immediately after the surgery. The animals of experimental groups and positive control group were slaughtered after subsequent periods of 90 and 180 days. In these periods, the histological analysis and image assessment by cone bean tomographic imaging were obtained. RESULTS: There was highest bone tissue formation with statistically significant results in the groups that associated biopolymer gel and membrane (Group I), followed by the group III (BMP, lyophilized graft and biological membrane). The lower bone formation occurred in the group not using the sugarcane biopolymer gel (Group II). The radiolucent areas of the analyzes of 180 days among the groups studied were respectively, 14.98 mm(2), 26.65 mm(2) and 35.81 mm(2). CONCLUSION: The biopolymer gel showed to be an excellent bone morphogenetic protein carrier, probably by facilitating the controlled release of these proteins in the process of bone repair.

Hydrogel of polysaccharide of sugarcane molasses as carrier of bone morphogenetic protein in the reconstruction of critical bone defects in rats

PURPOSE: To evaluate the benefit of using carriers such as the biopolymer gel (hidrogel of polysaccharide of sugarcane molasses) associated with the bone morphogenetic proteins (BMP's) in the repair of critical bone defects in calvaria of Wistar rats. METHODS: Forty-two rats were submitted to a surgical calvaria bone defects. These animals were divided into two experimental groups, positive control group and negative control group. The Group I the calvaria defect was filled up with biopolymer gel, biological membrane, BMP and lyophilized graft. The Group II was treated with biopolymer gel, BMP and lyophilized graft. And the group III (positive control group) was treated with BMP, lyophilized graft and biological membrane. In the negative control group (Group IV) a defect was made in the rat calvaria and the animals were sacrificed immediately after the surgery. The animals of experimental groups and positive control group were slaughtered after subsequent periods of 90 and 180 days. In these periods, the histological analysis and image assessment by cone bean tomographic imaging were obtained. RESULTS: There was highest bone tissue formation with statistically significant results in the groups that associated biopolymer gel and membrane (Group I), followed by the group III (BMP, lyophilized graft and biological membrane). The lower bone formation occurred in the group not using the sugarcane biopolymer gel (Group II). The radiolucent areas of the analyzes of 180 days among the groups studied were respectively, 14.98 mm², 26.65 mm² and 35.81 mm². CONCLUSION: The biopolymer gel showed to be an excellent bone morphogenetic protein carrier, probably by facilitating the controlled release of these proteins in the process of bone repair.

Análisis de las polihidroxialcanoato sintasas (PhaC1 y PhaC2) en una cepa de Pseudomonas fluorescens IBUN S1602, aislada en suelos colombianos / Analysis of polyhydroxyalkanoate synthases (PhaC1 and PhaC2) in a strain of Pseudomonas fluorescens IBUN S1602 isolated from Colombian soil

La cepa Pseudomonas fluorescens IBUN S1602 conforma el grupo de aislamientos provenientes de suelos colombianos de caña de azúcar, que acumula polihidrioxialcanoato (PHA), fue seleccionada como promisoria para escalamiento comercial por tener afinidad por sustratos alternativos y económicos como el glicerol, aceites usados, suero de leche, entre otros. Dada la importancia de la enzima sintasa en la síntesis de los PHAs, en el presente trabajo se realizó el análisis molecular de los genes phaC1 y phaC2 que codifican las enzimas sintasas tipo II (PhaC1 y PhaC2). Para la obtención de los amplímeros requeridos en la secuenciación, se utilizó la técnica de PCR bajo condiciones estandarizadas para iniciadores diseñados reportados en las bases de datos. Se identificaron dos fragmentos de 1680 pb y 1683 pb correspondientes a phaC1 y phaC2. El análisis comparativo de las secuencias proteicas resultantes de estos genes demuestra que la sintasa IBUN S1602 contiene la región α/β hidrolasa y 8 residuos de aminoácidos conservados, que son características de las sintasas examinadas a nivel mundial. Se analizó la estructura enzimática a nivel primario y se predijo la secundaria. Se concluyó que las sintasas de la cepa Pseudomonas fluorescens IBUN S1602 presentan alta homología con las sintasas tipo II que se reportan para Pseudomonas. Los resultados obtenidos contribuyen al entendimiento básico de la biosíntesis de PHA, la cual permitirá, en un futuro, el aumento de la calidad de PHA debida a la modulación del nivel de sintasa que se exprese en un organismo recombinante, con el fin de variar el peso molecular del biopolímero, propiedad esencial en el estudio de aplicaciones industriales.

The strain Pseudomonas fluorescens IBUN S1602 forms the group of isolates from colombian sugarcane soil´s, which accumulates polyhydroxyalkanoate biopolymer (PHA) and was selected as promising for commercial scale by having affinity for economic and alternative substrates such as glycerol, oils, whey, among others. Given the importance of the synthase enzyme in the synthesis of PHAs, was realized the molecular analysis of genes phaC1 and phaC2 which encode type II synthases (PhaC1 y PhaC2). To obtain the amplimers required in the sequencing, was used the PCR technique under standardized conditions for primers designed based on the updated review in databases. Were identified two fragments of 1680 bp and 1683 bp for phaC1 and phaC2. Comparative analysis of the resulting protein sequences of these genes shows that the IBUN S1602 synthases containing the region α/β hydrolase and 8 conserved amino acid residues that are characteristic of synthases examined worldwide. Enzyme structure was analyzed at the primary level and was predicted the secondary. It is concluded that synthase strain Pseudomonas fluorescens IBUN S1602 has high homology with type II synthases that are reported for Pseudomonas. The results contribute to basic understanding of the biosynthesis of PHA, and will allow in the future, increasing the quality of PHA due to modulation of the level of synthase is expressed in a recombinant organism, in order to vary the weight molecular biopolymer, an essential property in the study of industrial applications.

Rat adipose tissue-derived stem cells transplantation attenuates cardiac dysfunction post infarction and biopolymers enhance cell retention.

BACKGROUND: Cardiac cell transplantation is compromised by low cell retention and poor graft viability. Here, the effects of co-injecting adipose tissue-derived stem cells (ASCs) with biopolymers on cell cardiac retention, ventricular morphometry and performance were evaluated in a rat model of myocardial infarction (MI). METHODOLOGY/PRINCIPAL FINDINGS: 99mTc-labeled ASCs (1x10(6) cells) isolated from isogenic Lewis rats were injected 24 hours post-MI using fibrin a, collagen (ASC/C), or culture medium (ASC/M) as vehicle, and cell body distribution was assessed 24 hours later by gamma-emission counting of harvested organs. ASC/F and ASC/C groups retained significantly more cells in the myocardium than ASC/M (13.8+/-2.0 and 26.8+/-2.4% vs. 4.8+/-0.7%, respectively). Then, morphometric and direct cardiac functional parameters were evaluated 4 weeks post-MI cell injection. Left ventricle (LV) perimeter and percentage of interstitial collagen in the spare myocardium were significantly attenuated in all ASC-treated groups compared to the non-treated (NT) and control groups (culture medium, fibrin, or collagen alone). Direct hemodynamic assessment under pharmacological stress showed that stroke volume (SV) and left ventricle end-diastolic pressure were preserved in ASC-treated groups regardless of the vehicle used to deliver ASCs. Stroke work (SW), a global index of cardiac function, improved in ASC/M while it normalized when biopolymers were co-injected with ASCs. A positive correlation was observed between cardiac ASCs retention and preservation of SV and improvement in SW post-MI under hemodynamic stress. CONCLUSIONS: We provided direct evidence that intramyocardial injection of ASCs mitigates the negative cardiac remodeling and preserves ventricular function post-MI in rats and these beneficial effects can be further enhanced by administering co-injection of ASCs with biopolymers.

Effect of polymeric diets in patients on continuous ambulatory peritoneal dialysis.

OBJECTIVE: To determine if a diet complemented with calcium caseinate is better than a natural high protein diet for increasing serum albumin levels in patients on continuous ambulatory peritoneal dialysis (CAPD). PATIENTS AND METHODS: A 4-month clinical trial involving 100 patients older than 18 years was performed. Patients were randomized into two groups: group A, high protein diet (1.4 g natural protein/kg target weight/day and 35 kcal/kg target weight/day); and group B, calcium caseinate (0.7 g calcium caseinate plus 0.7 g natural protein diet/kg target weight/day and 35 kcal/kg target weight/day). Serum levels of albumin, total proteins (TP), BUN, creatinine, glucose, urea, sodium, and potassium, and hematocrit, leukocytes, erythrocytes, and hemoglobin were analyzed at baseline and every 30 days. RESULTS: The final mean albumin value was, for group A, 3.04 +/- 0.39 g/dL, and for group B, 3.12 +/- 0.41 g/dL (p < 0.05); TP for group A, 6.29 +/- 0.47 g/dL, and for group B, 6.49 +/- 0.51 g/dL (p < 0.05); leukocytes for group A, 6888 +/- 1282/mm3, for group B, 7288 +/- 1878/mm3 (p = 0.05); BUN for group A, 47 +/- 11 mg/dL, for group B, 50 +/- 16 mg/dL (p = 0.05). Regression analysis showed a treatment effect in serum albumin and TP levels from the third month in both groups. In group B, a constant elevation of serum albumin of 0.19 mg/dL and TP of 0.27 mg/dL was observed in every month of treatment with calcium caseinate. In the regression analysis of group A we observed a smaller increase in serum albumin, 0.06 mg/dL, and in TP, 0.11 mg/dL, in each month of treatment with the high protein diet. Both differences are significant (p < 0.05). CONCLUSION: Calcium caseinate used in CAPD patients suffering from malnutrition increases serum albumin levels.