Chitosan Liquid Research Articles

Training on Identification of Hazardous Food Preservatives and Utilization of Chitosan as A Natural Preservative

Food preservation with borax and formaldehyde is still widely practiced. The use of borax and formaldehyde as food preservatives has a negative impact on health. Knowledge and skills to identify borax and formaldehyde content using simple, cheap, and easy techniques need to be trained. A simple technique for testing borax uses the turmeric method, while formaldehyde uses young papaya sap. The public also needs to be given an alternative, safe way of preserving food with chitosan. Participatory methods were used in this activity. The activity stages begin with preparation and socialization, training, monitoring, and evaluation. The activity was attended by 23 people on the first day and 17 people on the second day, including cadres of the FKK, PKK, Karang Taruna, Elderly Forum, LPMK, and culinary UKM. There was a significant increase in the knowledge of training participants with an N gain of 0.58, including the moderate or quite effective category. Participants also responded positively. Participants have the skills to detect borax using the turmeric method and formaldehyde using papaya sap. Training participants are also skilled in using liquid chitosan as a natural food preservative. The conclusion of this activity is that the training participants increased their knowledge about dangerous food preservatives, had the skills to detect borax and formaldehyde in food ingredients with simple technology, and applied liquid chitosan as a natural preservative.

The Influence of Chitin- and Chitosan-Based Soil Amendments on Pathogen Severity of Apple and Pear Scab

Apple and pear scab are foliar pathogens of apple and pear trees. Unmanaged, yield and aesthetic losses can be severe. The risk of resistance associated with over-reliance on fungicides means novel pathogen management methods and products are increasingly required. Chitin and chitosan are widely recognised as induced resistance (IR) agents that trigger plant defence responses that in turn enhance plant resilience to pathogen ingress. A container and field trial was conducted using apple (Malus sylvestris) and pear (Pyrus communis ‘Conference’) respectively to assess the efficacy of a range of liquid and granular chitin/chitosan-based IR agents and fertilisers against apple and pear scab. A synthetic fungicide (penconazole) spray program used within the UK for apple and pear scab control was included for comparison. Application of chitin/chitosan IR agents at concentrations above 1% caused phytotoxicity. Limited efficacy as scab protectants was also demonstrated when chitin/chitosan IR agents were applied at concentrations of 0.25%. However, chitin IR agents when applied at 0.5% and 1% and chitosan IR agents at 1% demonstrated efficacy as scab protectants and resulted in an increased leaf chlorophyll content, increased fruit yield, and reduced leaf scab severity when compared against the watered control. Only one of three chitin/chitosan fertilisers evaluated demonstrated efficacy as scab protectants (liquid chitosan). A synthetic fungicide penconazole spray program provided the greatest protection against apple and pear scab in the container trials. However, under field conditions the degree of scab control following application of chitin and chitosan at 1% and the chitosan containing fertiliser liquid chitosan was statistically comparable to fungicide treated trees. Results suggest application of an appropriate chitin/chitosan IR agent(s) and fertiliser offers a useful addition to existing methods of apple and pear scab management under field and container conditions.

Characteristics of tin oxide nanoparticles produced by pulsed laser ablation technique in various concentrations of chitosan liquid and their potential application as an antibacterial agent

Tin oxide nanoparticles (SnO2 NPs) have become a potential candidate as an antibacterial agent for gram-negative and gram-positive bacteria. In this present work, SnO2 NPs have been successfully synthesized in the chitosan liquid medium by using the pulse laser ablation method utilizing quite low energy Nd:YAG laser (30 mJ). The produced tin oxide nanoparticles were then applied as an antibacterial agent for gram-negative and gram-positive bacteria. Experimentally, a pulse Nd:YAG laser beam is irradiated and focused on the surface of a high-purity tin metal plate placed at the bottom of the Petri dish that is filled with chitosan liquid medium. The effect of chitosan concentrations (0.05%, 0.1%, and 0.2%) on the characteristics of produced SnO2 NPs was examined. The higher concentration of chitosan (0.2%) gains the smallest diameter size (15.05 nm) and lowest concentrations of produced tin oxide nanoparticles. The application of produced SnO2 NPs as the antibacterial agent was demonstrated using gram-negative (Escherichia coli) and gram-positive (Bacillus subtilis) utilizing disk diffusion technique. The result certified that increment of the SnO2 NPs concentrations (100, 125, and 150 ppm) increases the diameter of inhibition zone (DIZ) both for E coli and B subtilis bacteria, which approve that the produced tin oxide nanoparticles can effectively be used as antibacterial agents for both gram-negative and gram-positive bacteria.

Nematicidal effect of chitosan on Meloidogyne incognita in vitro and on tomato in a pot experiment

The present study investigated to evaluate the potential of liquid chitosan of three concentrations (0.5, 1 and 2%) on Meloidogyne incognita (Kofoid and White, 1919) Chitwood, 1949 in vitro and on tomato under controlled conditions ((24 ± 1 °C, 60 ± 5% humidity). In vitro assay, the effect of the liquid chitosan concentrations on suppressing of hatching from eggs and second juvenile larvae (J2) mortality was determined. The reducing effect of the concentrations on the number of gall and egg mass on tomato roots and the J2 density in the soil was evaluated under controlled conditions. All concentrations suppressed hatch and increased J2 mortality more than control in vitro. The most effective concentration was found at 2% in vitro and its nematicidal effect on egg and J2 was over 70%. The results demonstrated that 0.5, 1 and 2% concentrations were significantly decreased gall/root, egg mass/root and J2 in soil compared to negative control under controlled conditions. No statistically significant difference was found between the nematicidal effects of the concentrations on the gall and egg mass (P≤0.05). It has been determined that 1 and 2% concentrations better suppress the J2 in soil than 0.5%. Although the nematicidal effect of 2% concentration was high in vitro and under controlled conditions, it was determined that it negatively affected plant biomass. Also, only 1% concentration of chitosan application controlled M. incognita on tomato by 58%. The present results show that the use of 1% liquid chitosan concentration against M. incognita will be more effective.

Effectivity of uv-light exposure on bacterial and fungal growth in Channa striata collagen-chitosan composite dressing for wound healing

Introduction: Channa striata collagen-chitosan wound dressing (3:1 v/v) was founded contaminate by bacterial and fungal. Therefore, to suppress bacterial and fungal contamination in Channa striata collagen-chitosan composite dressing, it needs several efforts such as sterilization under Ultra-Violet Light Exposure. The study aimed to determine UV-light exposure duration to supress bacterial and fungal growth on C. striata collagen-chitosan composite dressing. Methods: C. striata collagen was extracted from skin and scales using 2% HCl for 48 hours, then neutralized using NaOH 1 M until collagen fibers appeared. Chitosan powder dissolved in 2% acetic acid. Afterward C. striata collagen and chitosan liquid (1:3 v/v) were mixed and formed until wound dressing was reached. Wound dressing was sterilized under UV exposure for 0, 5, 10, 15, and 30 minutes. Chitosan dressing was used as a negative control. Results: The results of the study showed that the total number of bacteria and fungi decreased significantly with increasing time of exposure of UV light on composites dressing with a value of p=0.001 for bacterial growth and a value of p= 0.005 for fungus growth. The UV exposure on collagen-chitosan dressing to reduce bacterial and fungal growth proved effective in 10 minutes. Conclusions: The UV light exposure treatment can reduce bacterial and fungal contamination on collagen-chitosan composites on each addition duration exposure descriptively.

Multiobjective Optimization Based on “Distance-to-Target” Approach of Membrane Units for Separation of CO2/CH4

The effective separation of CO2 and CH4 mixtures is essential for many applications, such as biogas upgrading, natural gas sweetening or enhanced oil recovery. Membrane separations can contribute greatly in these tasks, and innovative membrane materials are being developed for this gas separation. The aim of this work is the evaluation of the potential of two types of highly CO2-permeable membranes (modified commercial polydimethylsiloxane and non-commercial ionic liquid–chitosan composite membranes) whose selective layers possess different hydrophobic and hydrophilic characteristics for the separation of CO2/CH4 mixtures. The study of the technical performance of the selected membranes can provide a better understanding of their potentiality. The optimization of the performance of hollow fiber modules for both types of membranes was carried out by a “distance-to-target” approach that considered multiple objectives related to the purities and recovery of both gases. The results demonstrated that the ionic liquid–chitosan composite membranes improved the performance of other innovative membranes, with purity and recovery percentage values of 86 and 95%, respectively, for CO2 in the permeate stream, and 97 and 92% for CH4 in the retentate stream. The developed multiobjective optimization allowed for the determination of the optimal process design and performance parameters, such as the membrane area, pressure ratio and stage cut required to achieve maximum values for component separation in terms of purity and recovery. Since the purities and recoveries obtained were not enough to fulfill the requirements imposed on CO2 and CH4 streams to be directly valorized, the design of more complex multi-stage separation systems was also proposed by the application of this optimization methodology, which is considered as a useful tool to advance the implementation of the membrane separation processes.

Evaluation of Inducing Agents and Synthetic Fungicide Combinations for Management of Foliar Pathogens of Urban Trees

Unmanaged, foliar pathogens of urban trees can be detrimental to tree health and aesthetics. Overreliance on synthetic fungicides increasingly means alternative means of pathogen management are now required. The purpose of these studies was to investigate the efficacy of 3 commercially available agents, harpin protein, salicylic acid derivative, and liquid chitosan, which can initiate induced resistance (IR) in plants. IR agents were applied independently and in combination with a synthetic fungicide (boscalid + pyraclostrobin) against 2 foliar pathogens (Venturia pirina and Guignardia aesculi) under field conditions with Pyrus communis ‘Williams’ Bon Chrétien’ and horse chestnut (Aesculus hippocastanum) acting as tree hosts. These agents were tested over 3 consecutive years. In 4 of 5 field studies, the use of an IR agent alone reduced pathogen symptom severity, increased fruit/seed yield, and enhanced leaf chlorophyll content. In virtually all studies, application of boscalid + pyraclostrobin at 2/3 strength plus an IR agent provided the same degree of pathogen control as boscalid + pyraclostrobin at full strength. Application of boscalid + pyraclostrobin at 1/3 strength plus an IR agent provided a reasonable degree of foliar pathogen control. Results showed that a combined mix of an IR agent with a 1/3 reduced dose of boscalid + pyraclostrobin was as effective at reducing symptom severity of 2 foliar pathogens as boscalid + pyraclostrobin applied at full strength, provided at least 4 sprays were applied during a growing season.

Effect of Water and Organic Pollutant in CO2/CH4 Separation Using Hydrophilic and Hydrophobic Composite Membranes.

Membrane technology is a simple and energy-conservative separation option that is considered to be a green alternative for CO2 capture processes. However, commercially available membranes still face challenges regarding water and chemical resistance. In this study, the effect of water and organic contaminants in the feed stream on the CO2/CH4 separation performance is evaluated as a function of the hydrophilic and permselective features of the top layer of the membrane. The membranes were a commercial hydrophobic membrane with a polydimethylsiloxane (PDMS) top layer (Sulzer Chemtech) and a hydrophilic flat composite membrane with a hydrophilic [emim][ac] ionic liquid–chitosan (IL–CS) thin layer on a commercial polyethersulfone (PES) support developed in our laboratory. Both membranes were immersed in NaOH 1M solutions and washed thoroughly before characterization. The CO2 permeance was similar for both NaOH-treated membranes in the whole range of feed concentration (up to 250 GPU). The presence of water vapor and organic impurities of the feed gas largely affects the gas permeance through the hydrophobic PDMS membrane, while the behavior of the hydrophilic IL–CS/PES membranes is scarcely affected. The effects of the interaction of the contaminants in the membrane selective layer are being further evaluated.

Utilization of Chitosan as Coating Material in Making NPK Slow Release Fertilizer

AbstractIn the implementation of fertilization, only about 50% of the fertilizer can be absorbed by plants while some are degraded or drifted by groundwater so that fertilization becomes inefficient which will also pollute the environment with the content of N, P, and K. The loss of N as nitrogen gas due to denitrification is up to 30–40%, the loss of N as ammonia gas due to volatilization is about 10–20, the loss of N as nitrate due to the washing by water flow is about 44%, and erosion can reach 45%. One solution to this problem is using a slow release fertilizer (SRF) where the nutrient is released slowly within a certain time. The SRF technology modifies the fertilizer utilizing chitosan coating on granule surface of the fertilizer. Liquid chitosan is used for coating and it is sprayed on the surface of fertilizer granule in the rotary pan granulator. It is found that the resistance of the chitosan coated fertilizer in the water is about 3–6 months. The characteristics of the nutrients released from SRF NPK 16‐16‐16 coated with chitosan are about 103.26 mg nutrients of N, 21.8 mg nutrients of P, and 65.62 mg nutrients of K within a month of immersion time.

Fraksinasi dan karakterisasi asap cair dari kayu ulin (Eusideroxylon zwageri Teijsm. & Binn.) sebagai pelarut kitosan

The purpose of this reseach was to study the solubility of chitosan in liquid smoke as a preliminary study of the application of a combination of liquid chitosan as a bioimmunizer and growth booster in plants.Fractionation and characterization of liquid smoke from ulin wood (Eusideroxylon zwageri Teijsm. & Binn.) and its ability test as chitosan solvent have been performed. Fractional distillation done using a set of tools distillation each fraction,fraction 1 ( ≤ 100° C), the fraction 2 (101-120° C), and fraction 3 (121-140°C). The resulting liquid smoke was then measured degree of acidity, the total acid analysis, the specific gravity, chitosan solubility test in liquid smoke. The result of the research showed that the liquid smoke recovery value of fractionation distillation of each fraction was 54.91; 29.39; and 8.8 (%). The result of liquid smoke characterization of each fraction obtained pH value fraction 1, fraction 2, and fraction 3 are respectively 2.33; 2.14; and 2.08, the total acid was 2.97; 4.59; and 8.88 (% g/mL), the specific gravity was 1,005; 1,006; and 1.009, and the phenol content was respectively 2.06; 3.67; and 2.30 (g/L). The solubility of chitosan in liquid smoke increasing with the concentration of each liquid smoke fraction and 5% (v/v) of liquid smoke concentration was able to dissolve chitosan more than 50 g/L.

CHITOSAN AS ANTIFUNGAL IN CHANNA STRIATA COLLAGENCHITOSAN FOR WOUND HEALING

The Snakehead fish contains high protein that was mostly used as a treatment during healing process in either invasive or passive surgery. Therefore, it could be developed as well as a mixture of wounds dressing for skin healing. The aim of this study was to know the effect of combination of concentrations between chitosan and collagen of Snakehead fish (Channa striata) skin and scales on fungal total number recovered from the composite. Snakehead fish skin and scales was treated by soaking in 2% HCl solvent for 48 hours to obtain collagen from its filtrate. Filtrate obtained continued to neutralize with 1 M NaOH until soluble collagen appeared. Collagen obtained in this study then mixed with 2% chitosan liquid to make wound dressing in various concentrations group. Combination of colagen mixture in this study were chitosan liquid only as control, 25% collagen-75% chitosan (C1), 50% collagen-50% chitosan (C2) and 75% collagen-25% chitosan (C3). The study results showed that on Control, C1 and C2 group there was no fungal contamination, but on C3 group there was contamination of fungal with total counting about 2,43 x 103 CFU. Based on statistically test showed that there was discrepancy for each group with p-value was 0,02 (p<0,05).

Biocoagulant of blood based on chitosan nanoparticle from crustacea

Chitosan is a chitin derivative natural polymer compound isolated from aquaculture waste, such as a crab shell that is the most chitosan source. Nanocitosan as a drug delivery offers delivery with non-harmful routes such as oral, nose, eye, and absorption. Nanokitosan can be absorbed by human organs that have nano-sized membrane penetration capabilities such as the kidneys, liver, and lungs where nanoparticles are 1-1,000 nm in size. Chitosan nanoparticles are prepared by ionic gelation techniques. The mechanism of this method is the formation of chitosan nanoparticles based on the electrostatic interaction between the positive amine groups on chitosan (-NH2) with the negative charge group of polyanion tripolyphospate (TPP). The first step is the preparation of chitosan, crab shell waste which is smoothed to 60 mesh, after subsequent smrubination to be smoothed to remove the protein content by dissolved in 3 N NaOH, then crude chitin demineralized to eliminate the mineral content contained in the crab shell with the addition of HCl 1 N and the presence of heating and stirring. The chitin obtained then enters the deacetylation stage to remove the acetyl group present in the crab shell by adding 50% NaOH and carried out by heating and stirring. The chitosan obtained was then dissolved in 3% lactic acid to obtain liquid chitosan, then added NaTPP to reduce the chitosan particle size to nano size. The obtained nitrocitosan size is 688 nm distribution with variation of NaTPP addition of 0.1% concentration and stirring 60 minutes. The resulting nitocytosan is tested to increase the rate of blood clotting that has been shown to shorten blood clotting time by up to 30 seconds.

Injectable freeze-dried chitosan-platelet-rich-plasma implants improve marrow-stimulated cartilage repair in a chronic-defect rabbit model.

Bone-marrow stimulation (BMS) improves knee-joint function but elicits incomplete repair. Liquid chitosan (CS)-glycerol phosphate/blood clots have been shown to improve BMS-based cartilage repair. Platelet-rich-plasma (PRP)-a rich source of growth factors and cytokines-improves recruitment and chondrogenic potential of subchondral mesenchymal stem cells. We hypothesised that repair response in a rabbit chronic-defect model will improve when freeze-dried CS/PRP is used to augment BMS. Bilateral trochlear defects created in New Zealand white rabbits were allowed to progress to a chronic stage over 4weeks. Chronic defects were debrided and treated by BMS in second surgery, then augmented with PRP (BMS+PRP) or freeze-dried CS/PRP implants (BMS+CS/PRP). The quality of 8-week repair tissue was assessed by macroscopic, histological, and micro computed tomography (Micro-CT) analysis. ICRS macroscopic scores indicated fibrocartilaginous or fibrous repair in control defects that were improved in the BMS+CS/PRP group. An overall improvement in repair in BMS+CS/PRP group was further confirmed by higher O'Driscoll scores, %Saf-O and %Coll-II values. Micro-CT analysis of subchondral bone indicated ongoing remodelling with repair still underway. Quality and quantity of cartilage repair was improved when freeze-dried CS/PRP implants were used to augment BMS in a chronic defect model.

POTENSI PEMANFAATAN KITOSAN TERMODIFIKASI ASAP CAIR SEBAGAI BAHAN EDIBLE COATING ANTI MIKROBA UNTUK PENGAWETAN DAGING


 This research is a preliminary study of the utilization of chitosan modified with liquid smoke to produce edible coating material that can be used as a preservative of beef. Chitosan compounds obtained from shrimp shell waste, while liquid smoke produced from pyrolysis of palm shells at a temperature of 340oC. Edible coating solution with various concentrations was made by dissolving chitosan (1-1.5%) into 3% liquid smoke, which was then applied as a meat preservative. Meat samples that have been dipped edible coating for 15 minutes, then stored in the refrigerator and observed decreased endurance every 24 hours for 8 days. Analysis results of Gas Chromatography-Mass Spectrometry (GC-MS) showed that liquid smoke contains phenol and acetic acid compounds that have antimocrobial properties. Meat endurance test was done by analyzing the aroma, texture and color of meat. The results showed that the beef that has been coated liquid chitosan solution can last up to 7 days. Chitosan concentration affects the endurance of meat, the greater the chitosan concentration, the better the meat endurance. The optimum concentration was obtained at 1% of chitosan, the meat still has an acceptable aroma, texture and color for up to 6 days. This suggests that chitosan-liquid smoke can be used as an edible coating material.

Synergistic antifungal effect of chitosan-stabilized selenium nanoparticles synthesized by pulsed laser ablation in liquids against Candida albicans biofilms.

BackgroundCandida albicans is a major opportunistic fungal pathogen. One of the most important virulence factors that contribute to the pathogenesis of candidiasis is its ability to form biofilms. A key characteristic of Candida biofilms is their resistance to antifungal agents. Due to significant morbidity and mortality rates related to biofilm-associated drug resistance, there is an urgency to develop novel nanotechnology-based approaches preventing biofilm-related infections.MethodsIn this study, we report, for the first time, the synthesis of selenium nanoparticles by irradiating selenium pellets by nanosecond pulsed laser ablation in liquid chitosan as a capping agent. Synergy of the fungicidal effect of selenium nanoparticles and chitosan was quantified by the combination index theorem of Chou–Talalay.ResultsThis drug combination resulted in a potent fungicidal effect against a preformed C. albicans biofilm in a dose–response manner. By advanced electron microscopy techniques, we documented the adhesive and permeabilizing properties of chitosan, therefore allowing selenium nanoparticles to enter as the cell wall of the yeast became disrupted and distorted. Most importantly, we demonstrated a potent quantitative synergistic effect when compounds such as selenium and chitosan are combined.ConclusionThese chitosan-stabilized selenium nanoparticles could be used for ex vivo applications such as sterilizers for surfaces and biomedical devices.

Konsentrasi Efektif Daya Antibiofilm Kitosan Cangkang Udang terhadap Streptococcus Viridans (The Effective Concentration of Antibiofilms Capacity from Shrimp Shells Chitosan towards Streptococcus Viridans)

Background.Periapical tooth infection is one of infection problems which often happens such as abscess periapical which is caused by bacteria. The bacteria which can form biofilms is named streptococcus viridans. It is resistant towards an antibacterial agent. Chitosan made of shrimp shells is used as a natural antibiofilms agent for streptococcus viridans. Purpose.To determine the effective concentration of antibiofilms capacity from shrimp shells chitosan towards streptococcus viridans. Method.The research method used in this research is laboratory experimental research. The research design is post-test only controlgroup design. Streptococcus viridans is given vortex until it becomes homogeneous with standard turbidity McFarland of 0.5, than, it is planted inside a microtitter plate using TSB Glu for 5x24 hours. At last, Streptococcus viridans is colored using crystal violet and the picture of biofilms is observed using inverted microscope. Chitosan liquid diluted through various concentration 0.195%, 0.39%, 0.78%, 1.56%, 3.125%, 6.25%, 12.5%, 25%, 50% and 100% are going to be added to the microtitter plate and being incubated for 24 hours. The interpretation of the result on the longitude of the wave through optical density is 570nm. Result.There is a significant difference between the concentration of 100%, 50%, 25%, 12.5%, 6.25%, 3.125%, 1.56%, 0.78%, and 0.39% and the control group. Chitosan’s effective concentration in resisting the biofilms is 50%. The result is determined by statistical analysis. Conclusion.The effective concentration to resist the formation of Streptococcus viridans biofilms using shrimp shells chitosan is 50%.

Using electrochemical oxidation of Rutin in modeling a novel and sensitive immunosensor based on Pt nanoparticle and graphene–ionic liquid–chitosan nanocomposite to detect human chorionic gonadotropin

This study aims at developing an innovative electrochemical immunoassay system for an ultrasensitive detection of human chorionic gonadotropin (hCG). hCG is a secretion of the placenta during pregnancy and gestational trophoblastic diseases. It increases as a consequence of abnormal placental invasion and placental immaturity. Thus, an exact diagnosis of the concentration of hCG in urine or serum plays an important role in monitoring trophoblastic diseases in all modern immunological pregnancy tests. In this work, a novel immunosensor is constructed by covalent immobilization of Pt nanoparticles (PtNPs) onto robust nanocomposite containing graphene (Gr), chitosan (Chit) and 1-methyl-3-octyl imidazolium tetrafluoroborate as ionic liquid (IL) (Gr–IL–Chit). The nanocomposite not only led to increase the electrode surface area and accelerate the electron transfer kinetics, but also it could provide a highly stable matrix to enhance the loading amount of the nanoparticles. PtNPs acts as a linker to immobilize hCG antibody onto the modified electrode. The amine groups of the antibody are covalently attached to PtNPs. Cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) were employed to trace the assembly process of the immunosensor. In this study, we used Rutin (RU) for the first time as the redox probe in the development of the electrochemical immunosensor. Upon biorecognition hCG to its antibody, peak current of RU decreased due to the formation of hCG–anti hCG complex. Through differential pulse voltammetry (DVP) experiments, it was found that proposed immunosensor could detect hCG at two broad linear ranges: 0.00106–2.12 and 2.12–350mIU/mL and a low detection limit of 0.00035mIU/mL. The immunosensor was found stable, reproducible, and highly specific for hCG detection.

Synthesis and antifungal property of N-(aryl) and quaternary N-(aryl) chitosan derivatives against Botrytis cinerea

A series of N-(aryl) and their quaternary N-(aryl) chitosan derivatives were synthesized and evaluated for their antifungal activity against crop-threatening fungus Botrytis cinerea. Schiff bases were firstly synthesized by the reaction of chitosan with cinnamaldehyde, cuminaldehyde and 4-dimethylaminobenzaldehyde followed by reduction with sodium borohydride to form N-(aryl) chitosans. Quaternary N-(aryl) chitosans were then obtained by reaction of N-(aryl) chitosan compounds with ethyl iodide. The chemical structures were characterized by 1H-NMR, FT-IR and UV spectroscopic techniques. The antifungal activity was evaluated in vitro against B. cinerea by mycelial growth inhibition method and in vivo by application of compounds to tomato plants prior to inoculation with fungal spores. In an in vitro experiment, all quaternized chitosans were more active than N-(aryl) chitosan derivatives and N,N,N-(diethylcinnamyl) chitosan (QC1) was the most potent (EC50 = 1,147 mg/L) against mecelia however, N,N,N-(diethyl-p-dimethylaminobenzyl) chitosan (QC3) was the most potent (EC50 = 334 mg/L) against spores. In an in vivo study, no disease incidence (0.0 %) was observed with QC1 and QC3 at 1,000 mg/L. Spray liquid chitosan enhanced total phenolics and guaiacol peroxidase in inoculated leaves.

Injectable gel scaffold based on biopolymer microspheres via an enzymatic reaction.

Injectable gel scaffolds are produced via an enzymatic reaction and extra electrostatic interactions between enzymatic peptide-functionalized heparin microspheres and a chitosan liquid phase. As a result of the controllability of this approach, the gel scaffolds with double-network structures can render the formulation of a therapeutically effective platform for tissue engineering.

Prevascularization of biofunctional calcium phosphate cement for dental and craniofacial repairs

ObjectivesCalcium phosphate cement (CPC) is promising for dental and craniofacial repairs. Vascularization in bone tissue engineering constructs is currently a major challenge. The objectives of this study were to investigate the prevascularization of macroporous CPC via coculturing human umbilical vein endothelial cells (HUVEC) and human osteoblasts (HOB), and determine the effect of RGD in CPC on microcapillary formation for the first time. MethodsMacroporous CPC scaffold was prepared using CPC powder, chitosan liquid and gas-foaming porogen. Chitosan was grafted with Arg-Gly-Asp (RGD) to biofunctionalize the CPC. HUVEC and HOB were cocultured on macroporous CPC-RGD and CPC control without RGD for up to 42d. The osteogenic and angiogenic differentiation, bone matrix mineral synthesis, and formation of microcapillary-like structures were measured. ResultsRGD-grafting in CPC increased the gene expressions of osteogenic and angiogenic differentiation markers than those of CPC control without RGD. Cell-synthesized bone mineral content also increased on CPC-RGD, compared to CPC control (p<0.05). Immunostaining with endothelial marker showed that the amount of microcapillary-like structures on CPC scaffolds increased with time. At 42d, the cumulative vessel length for CPC-RGD scaffold was 1.69-fold that of CPC control. SEM examination confirmed the morphology of self-assembled microcapillary-like structures on CPC scaffolds. SignificanceHUVEC+HOB coculture on macroporous CPC scaffold successfully achieved prevascularization. RGD incorporation in CPC enhanced osteogenic differentiation, bone mineral synthesis, and microcapillary-like structure formation. The novel prevascularized CPC-RGD constructs are promising for dental, craniofacial and orthopedic applications.