Chitosan Concentration Research Articles

Ethyl cellulose-chitosan microspheres of sumatriptan succinate for nasal drug delivery

The research investigated the preparation of mucoadhesive microspheres using ethyl cellulose and chitosan as polymers. Two methods were employed, with the first method utilizing an emulsion solvent evaporation technique and the second method incorporating additional homogenization and sonication steps. The results showed that the first method yielded nearly perfect spherical microspheres with a particle size range of 50 µm, while the second method produced irregularly shaped microspheres with larger particle sizes within the range of 200 µm. The drug entrapment efficiency was significantly higher in the first method compared to the second method, and within the first method, drug entrapment efficiency decreased with increasing chitosan concentration. These findings underscore the importance of method selection and chitosan concentration in microsphere synthesis, providing insights for optimizing drug delivery systems for targeted applications.

Preparation and characterization of polyphenol-loaded microcapsules based on zeaxylated protein

Pomegranate seeds are rich in polyphenols, known for their significant health benefits. In this study, we developed microcapsules to encapsulate pomegranate seed polyphenols (PSP) using a combination of zeaxylated protein (Zein) and chitosan (Cs). The optimization process involved a Zein to Cs volume ratio of 1:1, a chitosan concentration of 1.0 mg mL−1, and a polyphenol concentration of 2.0 mg mL−1. Scanning electron microscopy confirmed the formation of Zein/Cs/PSP complex coacervates, indicating the successful encapsulation. Fourier-transform infrared spectroscopy provided further evidence of electrostatic attraction between PSP and the Zein/Cs matrix. Differential scanning calorimetry analysis demonstrated the successful incorporation of PSP into the Zein/Cs wall material. Moreover, the encapsulated core material exhibited exceptional storage stability and retained its antioxidant activity. Notably, more than 85% of the encapsulated PSP remained intact after 5 h of simulated intestinal fluid digestion. This study underscores the potential of pomegranate seeds for comprehensive utilization in food engineering.

Formulasi Sediaan Patch dari Ekstrak Daun Salam (Syzygium polyanthum [Wight.] Walp.)dan Uji Aktivitas Antibakteri Propionibacterium acne Secara In Vitro

The use of S. polyanthum as an alternative to treat acne has been widely studied because it contains active substances that have antibacterial properties against Propionibacterium acne. The formulation of S. polyanthum extract into a patch preparation has many advantages. This study aimed to formulate and evaluate the physical properties of S. polyanthum extract patches, and determine their antibacterial activity against Propionibacterium acne. Patch preparations were made using the solvent casting method in 6 formulas with various polymer concentrations. Evaluation of the preparations included organoleptic tests, weight uniformity, thickness, pH, folding resistance, swelling, and turbidity. Antibacterial activity test against Propionibacterium acne was carried out on the resulting extract and patch preparations. The resulting patch provides a distinctive color and aroma of the extract, with a weight between 0.036–0.050 mm, thickness between 0.21–0.30 mm, pH between 4.43–5.06, folding power >500 folds, swelling percentage in medium phosphate buffer, pH 5.8, between 19.2%-30.8%, and distilled water between 18.8%-29.2%, and turbidity in medium phosphate buffer, pH 5.8, between 5.50–8.16 NTU, and distilled water between 4.02–5.57 NTU. S.polyanthum extract had the largest inhibition zone at 5% concentration, namely 13.56±1.40 mm. Meanwhile, patch preparations had the greatest inhibition in F1, namely 11.31±0.175 mm. S. polyanthum extract can be formulated into patches with a concentration of 5% at various concentrations of HPMC and chitosan. Patch preparations on F1 with a comparison of HPMC : chitosan (7:3) gave the largest inhibition zone against Propionibacterium acne, namely 11.31±0.175 mm.

Development of alginate beads for precise environmental release applications: A design of experiment based approach and analysis

Controlled release of active ingredients are important for drug delivery and more recently environmental applications including modulated dosing of chemical and biological controls. This study demonstrates the importance of investigating various material science factors that can influence the diffusion rates of alginate beads to improve and tune their performance for marine environmental applications. This investigation aimed to design a rational workflow to aid in leveraging alginate bead use as a carrier matrix for releasing a specific active agent into water. Experiments were conducted to focus on the narrow a large list of relevant material formulation parameters, which included chitosan molecular weight, chitosan concentration, calcium concentration, drop height, and bead size. Once the most relevant material preparation methods were screened, a more robust statistic Design of Experiments approach was performed and results determined the important (and unimportant) factors for increasing dye release kinetics in marine water. The process was further streamlined by narrowing the critical experimental factors to a three-level based on the prior analysis: chitosan MW, chitosan concentration, and bead size. Analysis of the collected data indicated that while chitosan MW had a negligible impact (Fstatistic = 0.22), bead size (Fstatistic = 60.33) significantly influenced the diffusion rates based on surface area. However, chitosan MW had minor effects where lower chitosan MW enabled higher product release rates. This case investigation was a novel application of the design of experiment approach towards environmental applications to understand differences in release rates to marine waters for the first time and the workflow provided also serve as the basis for researchers to optimize other environmental applications requiring optimization when it is unknown how a large number of formulation variables will impact performance in different environmental scenarios.

Tailoring polyethylene oxide-modified cross-linked chitosan/PVA nanofibrous membranes: Burn dressing scaffold developed for mupirocin release

In emergency treatment research, the focus on chitosan-based products for wound healing has been consistent. This study specifically explores a dressing made by mixing chitosan (CS) and poly (vinyl alcohol) PVA. Using electrospinning technology, nanofiber membranes of CS and PVA are created with the assistance of non-toxic and hydrophilic polyethylene oxide (PEO). The outcome is a new nanofibrous membrane loaded with mupirocin, designed for healing burn wounds.The study delves into the influence of PVA, CS, and PEO concentrations on the structural and chemical characteristics of the mats. This comprehensive exploration involves techniques such as Scanning Electron Microscope (SEM), Atomic Force Microscopy (AFM) imaging, Fourier Transform Infrared Spectrometry (FTIR analysis), and Contact angle measurements. Additionally, the research evaluates the antibacterial performance and biomedical behavior of the developed scaffolds.PEO proves beneficial in the electrospinning process, contributing to smoother fibers. Meanwhile, the addition of CS and mupirocin leads to formation of the thinner nanofibers (251 ± 5 μm and 263 ± 4 μm, respectively) and scaffolds with higher swelling (up to ∼3.5 times at 90 min). Notably, the (MTT) assay confirms the non-cytotoxicity of the fabricated nanofibers, with proliferations exceeding ∼85% for all samples.The crosslinked samples released the drug more slowly than the non-crosslinked dressings, with 80% of the scaffolds releasing the drug within 24 h. The in-vivo investigations suggested that the drug-containing scaffolds performed reliably and showed promise as a medical dressing for treating burn wounds.

Towards chitosan-amorphous calcium phosphate nanocomposite: Co-precipitation induced by spray drying

This article reports the successful one-step synthesis of two micron-sized composite powders consisting of chitosan and amorphous calcium phosphate. These composite materials are prepared by spray drying of a solution containing chitosan and calcium phosphate precursors. The co-precipitation of chitosan and calcium phosphate precursors during the process induces a highly homogeneous distribution of the phases. The mineral phase identified as spherical nanoparticles dispersed in chitosan showed no chemical bonding with the polymer. As demonstrated by electron microscopy, small angle X-ray scattering and spectroscopies, variation in chitosan concentrations significantly influences the size and spatial distribution of the mineral phase. These results present a promising approach for the preparation of chitosan/amorphous calcium phosphate composite powders with controlled and tunable properties with potential applications in the field of biomaterial engineering such as bone substitutes.

Effect of Different Concentrations of Chitosan on Germination and Growth of Sweet Thai Basil

Sweet Thai basil, Ocimum basilicum var. thyrsiflora is a medicinal plant that is widely used in many industries due to its richness in phytochemical contents. The present study was carried out to improve the germination growth and of sweet Thai basil. In the current research sweet Thai basil seeds were treated with different concentrations of chitosan (0, 2, 4 and 6 ml/L). The result showed that treatment at 4 ml/ L chitosan produced seed germination percentage 100, seed germination speed (1.51), vigor index (6.93) taller seedlings (7.69 cm in height), with bigger stem diameter (0.90 mm), leaf area (1.59 cm2/leaf), and root length (3.19 cm). However, 4 ml/L chitosan concentration was best compare to 0, 2 and 4 ml/L concentration of chitosan. On the other hand, it is recommended for the seeds of sweet Thai basil to be treated with 4 ml/L of chitosan with different plant density.

Tunable Release of Calcium from Chitosan-Coated Bioglass.

Bioglass presents a standard biomaterial for regeneration of hard tissues in orthopedics and dentistry. The notable osteo-inductive properties of bioglass are largely due to the release of calcium ions from it. However, this release is not easily controllable and can often be excessive, especially during the initial interaction of the biomaterial with the surrounding tissues. Consequently, this excessive release can deplete the calcium content of the bioglass, ultimately reducing its overall bioactivity. In this study, we have tested if applying biopolymer chitosan coatings of different thicknesses would be able to mitigate and regulate the calcium ion release from monodisperse bioglass nanoparticles. Calcium release was assessed for four different chitosan coating thicknesses at different time points over the period of 28 days using a fluorescence quencher. Expectedly, chitosan-coated particles released less calcium as the concentration of chitosan in the coating solution increased, presumably due to the increased thickness of the chitosan coating around the bioglass particles. The mechanism of release remained constant for each coating thickness, corresponding to anomalous, non-Fickian diffusion, but the degree of anomalousness increased with the deposition of chitosan. Zeta potential testing showed an expected increase in the positive double layer charge following the deposition of the chitosan coating due to the surface exposure of the amine groups of chitosan. Less intuitively, the zeta potential became less positive as thickness of the chitosan coating increased, attesting to the lower density of the surface charges within thicker coatings than within the thinner ones. Overall, the findings of this study demonstrate that chitosan coating efficiently prevents the early release of calcium from bioglass. This coating procedure also allows for the tuning of the calcium release kinetics by controlling the chitosan concentration in the parent solution.

Enhanced drug delivery and wound healing potential of berberine-loaded chitosan-alginate nanocomposite gel: characterization and in vivo assessment.

Berberine-encapsulated polyelectrolyte nanocomposite (BR-PolyET-NC) gel was developed as a long-acting improved wound healing therapy. BR-PolyET-NC was developed using an ionic gelation/complexation method and thereafter loaded into Carbopol gel. Formulation was optimized using Design-Expert® software implementing a three-level, three-factor Box Behnken design (BBD). The concentrations of polymers, namely, chitosan and alginate, and calcium chloride were investigated based on particle size and %EE. Moreover, formulation characterized in vitro for biopharmaceutical performances and their wound healing potency was evaluated in vivo in adult BALB/c mice. The particle distribution analysis showed a nanocomposite size of 71 ± 3.5 nm, polydispersity index (PDI) of 0.45, ζ-potential of +22 mV, BR entrapment of 91 ± 1.6%, and loading efficiency of 12.5 ± 0.91%. Percentage drug release was recorded as 89.50 ± 6.9% with pH 6.8, thereby simulating the wound microenvironment. The in vitro investigation of the nanocomposite gel revealed uniform consistency, well spreadability, and extrudability, which are ideal for topical wound use. The analytical estimation executed using FT-IR, DSC, and X-ray diffraction (XRD) indicated successful formulation with no drug excipients and without the amorphous state. The colony count of microbes was greatly reduced in the BR-PolyET-NC treated group on the 15th day from up to 6 CFU compared to 20 CFU observed in the BR gel treated group. The numbers of monocytes and lymphocytes counts were significantly reduced following healing progression, which reached to a peak level and vanished on the 15th day. The observed experimental characterization and in vivo study indicated the effectiveness of the developed BR-PolyET-NC gel toward wound closure and healing process, and it was found that >99% of the wound closed by 15th day, stimulated via various anti-inflammatory and angiogenic factors.

Optimisation of Chitosan as A Natural Flocculant for Microplastic Remediation

The objective of this study is to determine the optimal concentration of chitosan for microplastic remediation using the coagulation-flocculation method. The chitosan concentrations employed in this study include 10, 20, 30, and 40 ppm. The process of coagulation was conducted for one minute, with a rotational speed of 120 rpm. The process of flocculation was performed for 30 minutes with a rotational speed of 60 rpm. The findings of the study indicate that chitosan demonstrates a high efficacy in microplastic removal, resulting in a removal rate of 68.3%. Furthermore, the research findings indicate that the optimal concentration of chitosan for microplastic remediation was determined to be 30 ppm. The concentration of chitosan has a direct impact on the pH, TDS, COD, and BOD values. In general, an increase in chitosan concentration leads to a drop in pH and TDS values; conversely, an increase in chitosan concentration results in a rise in COD and BOD values.

The fundamental efficacy of hesperidin-loaded/chitosan-coated hybrid nanoparticles as a prospective regimen in wound healing amendment: In vitro and in vivo comprehensive study

Hesperidin (Hsd), a promising bioactive phytomedicine, possesses a wound-healing activity. However, its poor solubility necessitates frequent topical application of high doses. Hence, this study aimed to prepare and characterize Hsd-loaded hybrid nanoparticles (Hsd-HNPs), followed by surface coating with chitosan (CS) to overcome such obstacles.Hsd was first encapsulated in a poly (D, L-lactic-co-glycolic) acid/soy phosphatidylcholine (PLGA/SPC) matrix, producing Hsd-HNPs, which were evaluated to choose the most appropriate one (F2). Then, F2 was coated with three concentrations of CS, and F2/CS1 was the optimal one, with a homogenous particle size of 254.10 ± 4.59 nm, a positive zeta potential of 24.23 ± 2.70 mV, a percent Hsd entrapping efficiency of 60.41 ± 4.56 %, and a percent yield of 75.67 ± 2.36 %. The stability of F2/CS1 was studied at a refrigerated temperature of 4 ± 1 °C. Then, it was incorporated into a gel base and subjected to further investigation of ex vivo skin permeation and in vivo wound healing activity.F2/CS1 demonstrated good stability at 4 ± 1 °C. The results of permeation studies manifested an enhanced pattern of Hsd permeation from F2/CS1 gel compared to that of the free Hsd. After topical application of F2/CS1 gel to the induced wound rat model, a significant and prominent wound healing efficacy was emphasized by histopathological and immunohistochemical examinations. In conclusion, Hsd/CS-HNPs (F2/CS1) gel could be regarded as promising topical nanophytomedicine with enhanced permeation and potentiated wound healing activity.

Solubility Enhancement of Poorly Water-Soluble Drug Ritonavir using Polyvinylpyrrolidone and Chitosan-based Platform Technique

The antiviral medication ritonavir (RTV) belongs to the biopharmaceutics classification system (BCS) class II drug category and is known for its high permeability and poor solubility. Therefore, the prime objective of this research was to increase the rate of dissolution and improve the solubility of RTV using a polymer system. Solid dispersions consisting of binary polymer components i.e., chitosan (CH) and polyvinylpyrrolidone (PVP) were prepared using microwave microwave-assisted physical mixing technique and optimization of solid dispersion was performed with 32 factorial designs. Dispersions were analyzed for their physicochemical characteristics by the use of X-ray diffraction (XRD), differential scanning calorimetry (DSC), and fourier transform infrared spectroscopy (FTIR). The polymeric dispersions prepared were evaluated for the release of RTV throughout 1 h in 0.1N sodium chloride in a USP class II dissolving device. The phase solubility study demonstrated a considerable improvement in the saturation solubility of RTV when CH and PVP K30 were present either individually or in combination. Virtual interaction studies between the drug and polymers revealed physical interactions driven by van der Waals and hydrophobic forces between RTV and excipients. Carbonyl, amine, and hydroxyl groups, among others, were probably present in both RTV and CH, which allowed for these interactions to take place. There was no discernible interaction between the RTV and the polymers included in the FTIR research. The dispersion strategies have improved the dissolving rate, according to the in-vitro drug release investigation. A formulation including a polymeric dispersion of the optimal concentration of PVP and chitosan may efficiently boost the release of RTV, according to the in-vitro release profile.

CHITOSAN INHIBITS THE <i>IN VITRO</i> DEVELOPMENT OF <i>Colletotrichum</i> SP. FROM BANANA (<i>Musa x paradisiaca</i> L.) FRUITS

The banano (Musa x paradisiaca L.) is a tropical fruit, susceptible to infection by Colletotrichum sp. Fungicides are the most typical approach for controlling postharvest infections. Concerns regarding its negative impact on human health and the environment have prompted the quest for alternate remedies. Because of its antimicrobial activity, chitosan is an environmentally friendly alternative. This study aimed to determine the influence of chitosan on the in vitro development of Colletotrichum sp. isolated from banana fruits. Inhibition mycelial growth, spore concentration and spore germination were evaluated in three chitosan concentrations, 0.5 %, 1.0 % and 1.5 %. Optical, fluorescence, and scanning electron microscopy were used to examine the impact of chitosan on spore growth and morphology. We observed that chitosan solutions inhibited Colletotrichum species in vitro. Chitosan at 1.5 % significantly decreased the percentage of mycelial growth inhibition and spore concentration in comparison with the control. Compared to the control, a concentration of 1.5 % chitosan considerably decreased the mycelial growth and spore concentration. In addition, a complete inhibition of spore germination and a low mycelium content was observed with 1.0% and 1.5% chitosan, controlling the in vitro development of Colletotrichum sp. in banana fruits.

Chitosan Rheological Behavior in an Acidic Water Mixture for Pharmaceutical and Biomedical Applications

The importance of chitosan (CH) has grown significantly over the last two decades due to its renewable and biodegradable source, and also because of the recent increase in the our knowledge of its functionality in technological and biomedical applications. The present article reviews the biopolymer CH and its derivatives, as versatile biomaterials for potential drug delivery systems, as well as tissue engineering applications, analgesia and treatment of arthritis. CH and its derivatives, as natural antimicrobial agents, can be applied in biomedical, biotechnological, and pharmaceutical applications. Its antimicrobial activity depends on many factors such as its molecular size, source, associated components, concentration, and type of microorganism. In our research described here we prepared and characterized the dynamic viscosity and the rheological properties of a biopolymer material based on CH in solution in acidic water. The dynamic viscosity and shear stress were measured under the influence of an increasing CH concentration of 1–10 g/l and an increasing temperature of 288.15–318.15 K.

Biodegradable Plastic Synthesis Based on Kluwih Seeds (Artocarpus camansi) and Chitosan with the Addition of Glycerol

The natural resources of agricultural products have the potential to be raw material for making biodegradable plastic, one of which is starch from kluwih seeds (Artocarpus camansi). This study examines the potential of kluwih seed starch as a basic material for making biodegradable plastic. This research method is experimental, the raw material for making biodegradable plastic is the kluwih seed starch originating from Aceh Besar Regency, Aceh Province. Other additives used are chitosan as reinforcement and glycerol as plasticizers. The analysis is carried out, namely mechanical properties, morphology, thermal, functional groups, water absorption and degradation analysis. The results of the analysis of this study show that the kluwih seed starch functions as a basic material for making biodegradable plastic. As chitosan concentration increases, the resulting tensile strength increases with results obtained around 119.17-166.67 kgf/mm2, while the percentage of elongation is lower the results obtained are 6.82-11.15%. The morphological analysis shows the biodegrable plastic produced has a compact and homogeneous structure. The thermal analysis shows a good thermal stability to ranging from 180 to 370 oC. The results of the biodegradable plastic FTIR show wave numbers 1662.64–1049 cm-1. Water absorption analysis is obtained around 7.658-12.068%, a decrease in water absorption is influenced by the addition of chitosan concentration. Biodegradable paltic planted in the soil containing EM4 degraded for 3 days.

Ultrasound-Triggered Amoxicillin Release from Chitosan/Ethylene Glycol Diglycidyl Ether/Amoxicillin Hydrogels Having a Covalently Bonded Network.

An antibiotic release system triggered by ultrasound (US) was investigated using chitosan (CS)/ethylene glycol diglycidyl ether (EGDE) hydrogel carriers with amoxicillin (Amox) drug. Different CS concentrations of 1.5, 2, 2.5, and 3 wt % were gelled with EGDE and Amox was entrapped in the hydrogel carrier; the accelerated release was observed as triggered by 43 kHz US exposure at different US output powers ranging from 0 to 35 W. Among these CS hydrogel systems, the degree of accelerated Amox release depended on the CS concentration for the hydrogelation and the matrix with 2 wt % CS exhibited efficient Amox release at 35 W US power with around 19 μg/mL. The drug released with time was fitted with Higuchi and Korsmeyer-Peppas models, and the enhancement was caused by US aiding drug diffusion within the hydrogel matrix by a non-Fickian diffusion mechanism. The US effect on the viscoelasticity of the hydrogel matrix indicated that the matrix became somewhat softened by the US exposure to the dense hydrogels for 2.5 and 3% CS/EGDE, while the degree of softening was slightly marked in the CS/EGDE hydrogels prepared with 1.5 and 2% CS concentration. Such US softening also aided drug diffusion within the hydrogel matrix, suggesting an enhanced Amox release.

Mempertahankan Mutu Tomat dengan Penggunaan Konsentrasi Chitosan Coconut Crabs

Various studies have been carried out in post-harvest handling of tomatoes to maintain quality quality. Among them is research on the effect of ripeness level and concentration of Chitosan CC on the quality and quality of tomatoes (solanum lycopersicum L.), in addition to the influence of the type of packaging material, temperature and storage duration on the quality characteristics of tomatoes. However, research on post-harvest handling of tomatoes using newsprint packaging methods, dried banana leaves, Styrofoam lunch boxes and plastic PP has not been carried out. Therefore, this study aims to see the effect of post-harvest handling on tomato quality with the use of different edible coating chitosan coconut crabs (Cs CC). This study used a Complete Randomized Design (RAL) with 1 factor consisting of 5 treatments using Chitosan Coconut Crabs (Cs CC). The treatment is as follows: P0 = Control, P1 = Cs CC 1%, P2 = Cs CC 2%, P3 = Cs CC 3%, P4 = Cs CC 4%. The results showed that tomatoes with early ripeness level showed weight loss, and a significantly higher level of consumer favorability, as well as a significantly lower level of fruit hardness compared to tomatoes with early green ripeness. The results of research on the effect of using edible coating crab shell waste are proven to maintain tomato weight loss of less than 10% during storage time with treatment, the higher the concentration of edible coating will inhibit shrinkage, the smaller weight shrinkage. In the results of the study, the best value was produced in research with an edible coating concentration of 0.75% with the lowest weight shrinkage value of 5.22%. Tomatoes with early ripeness level of turning show shrinkage, and a significantly higher level of consumer favorability, as well as a significantly lower level of fruit hardness compared to tomatoes with an early green ripeness. Chitosan concentration of 2 % significantly increases the solute content of tomato fruits.

The impact of chitosan in experimental resin with different photoinitiator systems

Objectiveto investigate the effect of different concentrations of chitosan added to experimental resins containing either BAPO or camphorquinone (CQ) as photoinitiators, regarding degree of conversion (DC), flexural strength (FS), flexural elastic modulus (E), Knoop microhardness (KHN), cytotoxicity, genotoxicity and antimicrobial activity. MethodsExperimental resins with polymeric matrix of BisGMA and TEGDMA was added either 0.5 wt% BAPO or 0.5 wt% camphorquinone/0.2% amine along with and chitosan concentrations of 0.5%; 1.0% or 2.0%. Degree of conversion was measured using Fourier transformed infrared spectroscopy. Flexural strength and elastic modulus were obtained through three-point bending test and Knoop microhardness was measured in a microidenter. Direct cytotoxicity was performed in human keratinocytes and genotoxicity test was done in murine macrophages cells. Antimicrobial activity was acessed against Staphylococcus aureus and Streptococcus mutans through the inhibition halo. Data were analyzed using two-way ANOVA and Tukey teste (α = 0.05). Results: The materials containing photoinitiator BAPO showed higher values of DC, FS, E, and KHN compared to resins with CQ. The addition of chitosan did not affect the properties of these materials. However, in resins containing CQ, the addition of chitosan improve these properties compared to control group. For the groups containing BAPO the chitosan reduced cytotoxicity and genotoxicity compared to materials with camphorquinone. The materials with 1.0% and 2.0% chitosan showed increased antibacterial activity in the materials containing BAPO as photoinitiator for both bacteria. Significance: The alternative photoinitiator BAPO and chitosan can improve physical and biological properties of photoactivated resins when compared with the materials with photoinitiator camphorquinone.

Actividad de recubrimientos de quitosano, nanopartículas de quitosano y ZnO contra hongos aislados e identificados molecularmente de frutas con potencial de exportación en la zona norte del Perú

Las pérdidas postcosecha de frutas de exportación originan cuantiosas pérdidas económicas, siendo la acción de hongos una de las principales causas. Para el control de estos se utilizan fungicidas, muchos de los cuales tienen alta toxicidad y poder residual. La búsqueda de alternativas al uso de estos se convierte en un tópico importante de investigación. La presente investigación tuvo como objetivo evaluar recubrimientos basados en quitosano, nanopartículas (NPs) de quitosano y ZnO para inhibir hongos aislados de frutas con potencial de exportación en el norte del Perú. En primer lugar, los hongos se aislaron e identificaron, molecularmente en base al gen internal transcribed spacer (ITS), de arándano, limón, uva y aguaymanto. Se prepararon recubrimientos líquidos de quitosano, con diferentes concentraciones de nanopartículas de quitosano y ZnO. Estos recubrimientos fueron evaluados in vitro sobre parte de los hongos aislados utilizando la técnica de halos de inhibición. Los recubrimientos preparados presentaron efecto antifúngico contra Alternaria Alternata (arándano), Aspergillus tubingensis (limón), Aspergillus niger (limón), Thielaviopsis ethacetica (limón) y Aspergillus niger (aguaymanto). Se determinó que la concentración de NPs de quitosano no tuvo ningún efecto sobre la capacidad antifúngica de los recubrimientos, mientras que las NPs de ZnO si tuvieron un efecto directamente proporcional. Los recubrimientos en base a quitosano y NPs de quitosano y ZnO tienen un potencial de uso como agente antifúngico en frutas de exportación.

Glucose-Sensitive Biosensor Design by Zinc Ferrite (ZnFe2O4) Nanoparticle-Modified Poly (o-toluidine) Film

Glucose oxidase (GOD) immobilized poly(o-toluidine) (POT) coated Pt electrode was designed for glucose-sensitive biosensor. Since POT film structure affects enzyme activity, parameters of enzyme immobilization and POT synthesis conditions were optimized. Optimal monomer concentration for POT film synthesis was determined as 40 mM and the scanning rate was determined as 50 mV/s. As for the immobilization process results, GOD, glutaraldehyde (GAL) and chitosan (Chi) concentrations were decided as 2 mg/ml 0.10%, and 0.5% for the Pt/POT electrode. Zinc ferrite nanoparticle (ZnFe2O4NP) was immobilized together with POT film in the presence of GOD enzyme. It was revealed that ZnFe2O4NP increased the current responses and stability of the Pt/POT electrode.