Size Of Nanogels Research Articles

Design of enzyme immobilized zwitterionic copolymer nanogels and its size effect on electrochemical reaction

For enzyme-based electrochemical devices, an improvement in electron transfer between the enzyme and electrode is important. Thus, we developed a nano-scaled hydrogel that includes an electron mediator and enzyme to realize nano-sized effects that enhance the functions. Three different chain lengths (short, medium, and long) of copolymers composed of 2-methacryloyloxyethyl phosphorylcholine (MPC) and methacrylic acid N-hydroxysuccinimide ester (MNHS; poly(MPC-co-MNHS), PMS) were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. The PMS nanogels can bind to the amino ferrocene (AFc) of the electron mediator and glucose oxidase (GOD) as a catalyst. The mono-dispersive PMS nanogels approximately 200–250 nm in size bound with AFc were prepared with different polymer chain lengths and amounts of AFc (PMMFcX_Y%, X= ‘degree of polymerization, 50, 75, 100’ and Y= ‘AFc feeding ratio against the amount of NHS group in the polymer chain, 50 %, 100 %’). The size of PMMFcX_Y% could be controlled by changing degree of polymerization or AFc feeding ratio. After the modification of GOD to PMMFcX_Y%, their size increased slightly from the original size (ca. 200–250 nm) to approximately 250–300 nm. The catalytic activity of nanogel in dispersed system was higher than that of microgel, indicating that nanogels could improve glucose transport in hydrogel layer. Compared to the catalytic reaction of the PMMFc 75_50 %-GOD nanogel-modified electrodes with that of microgel modified electrode, the current response was improved by decreasing the nanogel size, as evaluated by electrochemical measurements. These results revealed that the smaller nanogels could improve both glucose transport and electron transfer via mediator by smaller size, resulting higher efficiency of enzyme immobilized electrode.

Potential of a CO2-Responsive supramolecular drug-carrier system as a safer and more effective treatment for cancer

We combined carbon dioxide (CO2)-responsive cytosine-containing rhodamine 6G (Cy-R6G) as a hydrophobic anticancer agent with hydrogen-bonded cytosine-functionalized polyethylene glycol (Cy-PEG) as a hydrophilic supramolecular carrier to construct a CO2-responsive drug delivery system, with the aim of enhancing the responsiveness of the system to the tumor microenvironment and thus the overall effectiveness of anticancer therapy. Due to self-complementary hydrogen bonding interactions between cytosine units, Cy-R6G and Cy-PEG co-assemble in water to form spherical-like nanogels, with Cy-R6G effectively encapsulated within the nanogels. The nanogels exhibit several distinctive physical features, such as widely tunable nanogel size and drug loading capacity for Cy-R6G, intriguing fluorescence properties, high co-assembled structural stability in normal aqueous environments, enhanced anti-hemolytic characteristics, sensitive dual CO2/pH-responsive behavior, and precise and easily controllable CO2-induced release of Cy-R6G. Cytotoxicity assays clearly indicated that, due to the presence of cytosine receptors on the surface of cancer cells, Cy-R6G-loaded nanogels exert selective cytotoxicity against cancer cells in pristine culture medium, but do not affect the viability of normal cells. Surprisingly, in CO2-rich culture medium, Cy-R6G-loaded nanogels exhibit a further significant enhancement in cytotoxicity against cancer cells, and remain non-cytotoxic to normal cells. More importantly, a series of in vitro experiments demonstrated that compared to pristine culture medium, CO2-rich culture medium promotes more rapid selective internalization of Cy-R6G-loaded nanogels into cancer cells through cytosine-mediated macropinocytosis and thus accelerates the induction of apoptosis. Therefore, this newly developed system provides novel avenues for the development of highly effective CO2-responsive drug delivery systems with potent anticancer capabilities.

Influencing Factors and Stimulus-Sensitivity of Chitosan/Polymethacrylic Acid (CS/PMAA) Nanogels as Nanocarriers

ABSTRACT Nanogel, nanosized hydrogel, can contribute to biomedical and pharmaceutical, especially in drug delivery, due to its enthralling properties. Small size, large surface area, hydrophilicity, and stimulus responsiveness of nanogel ameliorate tissue penetration, drug loading capacity, and targeted drug delivery. The current study prepared nanosized, pH-sensitive, biocompatible, and stable chitosan/polymethacrylic acid (CS/PMAA) based nanogels using MBA as a crosslinker and APS as an initiator. FTIR confirmed the reaction between functional groups to synthesize nanogels sufficiently in a spherical shape, as affirmed by a FESEM. DLS data revealed nanosized particles with a size range of 70–170 nm and a range of 6–13 for polydispersity index (PDI). A study showed that 2% of MBA crosslinker is sufficient to achieve the desired crosslinking in 60 minutes reaction time (RT) with nanogel size ~ 92 nm. Increasing RT from 30 to 80 minutes during nanogel synthesis demonstrated a decrease in nanogel sizes from 186–73 nm. Synthesized nanogels have shown pH sensitivity (stimuli responsiveness) in acidic and alkaline mediums with an increase in particle size in pH-2 (~144 nm) and pH-8 (~280 nm) compared to intermediate pHs. The pH sensitivity of nanogels by changing the size per the suspended medium’s pH is crucial for prolonged systemic circulation and targeted drug delivery. Moreover, nanogels have shown good colloidal stability with zeta potential (ZP) +28 mv in acidic and −38 mv alkaline mediums. DSC and XRD results demonstrated thermal stability and amorphous morphology of nanogels, respectively. BET surface analysis revealed the surface area of nanogels in the range of 65–68 cm2/g with an average pore size of 28–32 nm. In-vitro cytotoxicity in the L-929 cell line by MTT assay established the cell viability (>70%) after 24 hours of incubation, substantiating the non-toxicity and biocompatibility of nanogels as nanocarriers for drug delivery.

Nanoscopic gel particle for intra-articular injection formulation

Hyaluronic acid (HA) based nanogels showed effective intracellular delivery efficacy for anti-cancer and anti-inflammatory drugs, characterized by their ability targeting relevant cell receptors. In the present study, we demonstrate the ability of hyaluronic acid-polyethyleneimine (HA-PEI) nanogels as a promising dual-functional interfacial active for intra-articular injection to intervene arthritis. Nanomechanical measurements on both model substrates and human cartilage samples confirm that the HA-PEI nanogels can significantly improve interfacial lubrication, in comparison to HA molecules, or silica-based nanoparticles. We show that the Coefficient of Friction significantly decreases with a decreasing nanogel size. The exceptional lubricating performance, coupled with the proven drug delivery capability, evidences the great potential of nanoscopic hydrogels for early-stage arthritis treatment. The flexibility in choosing the chemical nature, molecular architecture, and structural characteristics of nanogels makes it possible to modulate both drug delivery kinetics and interfacial lubrication, thus representing an innovative approach to treat degenerative joint diseases.

Synthesis, characterization and stability of crosslinked chitosan-maltodextrin pH-sensitive nanogels

Polysaccharide-based nanogels offer a wide range of chemical compositions and are of great interest due to their biodegradability, biocompatibility, non-toxicity, and their ability to display pH, temperature, or enzymatic response. In this work, we synthesized monodisperse and tunable pH-sensitive nanogels by crosslinking, through reductive amination, chitosan and partially oxidized maltodextrins, by keeping the concentration of chitosan close to its overlap concentration, i.e. in the dilute and semi-dilute regime. The chitosan/maltodextrin nanogels presented sizes ranging from 63 ± 9 to 279 ± 16 nm, showed quasi-spherical and cauliflower-like morphology, reached a ζ-potential of +36 ± 2 mV and maintained a colloidal stability for up to 7 weeks. It was found that the size and surface charge of nanogels depended both on the oxidation degree of maltodextrins and chitosan concentration, as well as on its degree of acetylation and protonation, the latter tuned by pH. The pH-responsiveness of the nanogels was evidenced by an increased size, owed to swelling, and ζ-potential when pH was lowered. Finally, maltodextrin-chitosan biocompatible nanogels were assessed by cell viability assay performed using the HEK293T cell line.

Synthesis of Poly(methacrylamide‐co‐methacrylic acid) Nanogels: Effect of Synthesis Parameters on the Nanosize, Characterization and Stimuli‐Sensitive Characteristics

AbstractPoly(methacrylamide‐co‐methacrylic acid) P(MAAm‐co‐MAAc) nanogels were synthesized using emulsion polymerization method and characterized in terms of structure, stimuli‐sensitive behavior and nanosize. The effect of monomer, surfactant (sodium dodecyl sulfate) and cross‐linker (N,N′‐methylenebisacrylamide) concentration on the nanosize of the nanogels was investigated. The hydrodynamic size of nanogels was determined by dynamic light scattering (DLS) and it was found to be in the range of 109.8–146.1 nm. Polydispersity index (PDI) values were lower than 0.3 (in the range of 0.145–0.261) confirming the narrow size distribution of the nanogels. Zeta potential measurements indicated that the nanogels exhibited good stability. Stimuli‐sensitive behavior of the nanogels was evaluated using UV‐visible spectroscopy. Characterization of the nanogels was carried out by Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), X‐ray diffraction (XRD) and scanning electron microscopy (SEM).

Mucoadhesive, Fluconazole-Loaded Nanogels Complexed with Sulfhydryl-β-cyclodextrin for Oral Thrush Treatment.

The objective of this study was to generate fluconazole-loaded mucoadhesive nanogels to address the problem of hydrophobicity of fluconazole (FL). An inclusion complex was formulated with sulfhydryl-β-CD (SH-β-CD) followed by nanogels formation by a Schiff base reaction of carbopol 940 (CA-940) and gelatin (GE). For characterization, PXRD, FT-IR analysis, drug content, and phase solubility studies were performed. Similarly, nanogels were assessed for particle size, zeta potential, organoleptic, and spreadability studies. Moreover, drug contents, rheological, in vitro drug permeation, release kinetics, toxicity, and stability studies of nanogels were performed. Furthermore, mucoadhesive characteristics over the buccal mucosal membrane of the goat were evaluated. The nanogels formulated with a higher amount of CA-940 and subsequently loaded with the inclusion complexes of FL showed promising results. PXRD and FT-IR analysis confirmed the physical complexes by displaying a reduction in the intensity of peaks of FL. The average particle size of nanogels was in the range of 257 to 361 nm. The highest drug content of 88% was encapsulated within the FL-SH-β-CD complex. All formulations at 0.5-1% concentration displayed no toxicity to the Caco-2 cell lines. Nanogels loaded with FL-SH-β-CD complexes showed 18-fold improved mucoadhesion on the buccal mucous membrane of the goat when compared to simple nanogels. The in vitro permeation study exhibited significantly enhanced permeation and first-order concentration-dependent drug release was observed. On the bases of these findings, we can conclude that a mucoadhesive nanogel-based drug delivery system can be an ideal therapy for candidiasis.

Zwitterion-Modified Nanogel Responding to Temperature and Ionic Strength: A Dissipative Particle Dynamics Simulation.

The self-assembly and stimuli-responsive properties of nanogel poly(n-isopropylacrylamide) (p(NIPAm)) and zwitterion-modified nanogel poly(n-isopropylacrylamide-co-sulfobetainemethacrylate) (p(NIPAm-co-SBMA)) were explored by dissipative particle dynamics simulations. Simulation results reveal that for both types of nanogel, it is beneficial to form spherical nanogels at polymer concentrations of 5-10%. When the chain length (L) elongates from 10 to 40, the sizes of the nanogels enlarge. As for the p(NIPAm) nanogel, it shows thermoresponsiveness; when it switches to the hydrophilic state, the nanogel swells, and vice versa. The zwitterion-modified nanogel p(NIPAm-co-SBMA) possesses thermoresponsiveness and ionic strength responsiveness concurrently. At 293 K, both hydrophilic p(NIPAm) and superhydrophilic polysulfobetaine methacrylate (pSBMA) could appear on the outer surface of the nanogel; however, at 318 K, superhydrophilic pSBMA is on the outer surface to cover the hydrophobic p(NIPAm) core. As the temperature rises, the nanogel shrinks and remains antifouling all through. The salt-responsive property can be reflected by the nanogel size; the volumes of the nanogels in saline systems are larger than those in salt-free systems as the ionic condition inhibits the shrinkage of the zwitterionic pSBMA. This work exhibits the temperature-responsive and salt-responsive behavior of zwitterion-modified-pNIPAm nanogels at the molecular level and provides guidance in antifouling nanogel design.

Cationic Nanogels Enable Gold Nanoparticle Immobilization and Regulated Catalytic Activity.

Polyelectrolyte nanogel consisting of charged network is a prospective platform for developing nanoreactor due to their integrated features of both polyelectrolyte and hydrogel. In this work, cationic poly (methacrylatoethyl trimethyl ammonium chloride) (PMETAC) nanogels with regulated size (30-82 nm) and crosslinking degree (10-50%), has been synthesized by Electrostatic Assembly Directed Polymerization (EADP) method and applied to load gold nanoparticles (AuNPs). Based on the typical reduction reaction of 4-nitrophenol (4-NP), the catalytic performance of the constructed nanoreactor was examined by studying their kinetic process, where the loaded AuNPs exhibited dependent activity on crosslinking degree of nanogels, while independent catalytic activity on nanogel size. Our results validate that, polyelectrolyte nanogels are capable of loading metal NPs and regulating their catalytic performance, therefore demonstrates potential for developing functional nanoreactors.

The regulation of ethanol in reaction medium on the properties of nanogels prepared by photopolymerization at 532 nm

Nanogels with a unique three-dimensional structure have wide applications in tissue engineering and drug delivery. In this study, polyethylene glycol diacrylate (PEGDA) nanogels were prepared by photopolymerization under the irradiation of 532 nm laser using a mixture of ethanol and water as the solvent. The reaction parameters including laser power and stirring speed were systematically investigated. Since the amphiphilic PEGDA self-emulsifies to form micelles in water, the regulation of ethanol content in reaction medium can tune the size and morphology of nanogels. Based on these, the photopolymerization mechanism of PEGDA in aqueous solution of ethanol was proposed.

Additive-free synthesis of poly(n-vinyl pyrrolidone) and poly(n-isopropylacrylamide) nanogels with controlled sizes.

An easy method is proposed to prepare poly(vinyl pyrrolidone) (PVP) and poly(N-isopropylacrylamide) (PNiPAAm) nanogels with sizes less than 100 nm. The underlying principle is to prepare dilute polymer solutions in acetone/water mixtures where acetone acts to break tridimensional structure of water hence disrupting the H-bonds bridging polymer coils causing separation and shrinkage in their sizes. Irradiation of these solutions by gamma-rays directly leads to the formation of intramolecular crosslinks within the coils resulting with nanogels with sizes smaller than precursor coils. While the average size of nanogels of PVP irradiated in water only is 236 nm, they were reduced to about 44 nm when irradiation was carried out in acetone/water solutions at near theta compositions. PNiPAAm nanogels were also synthesized by irradiating their dilute acetone/water solutions. Multimodal coil size distribution of PNiPAAm was converted into monomodal distribution with 70 nm average size and low dispersity by the addition of acetone. Irradiation of such solutions yielded PNiPAAm nanogels with 50 nm average size. Stability of nanogels was followed for 1 year not showing any changes in their sizes or size distributions. Nanogels were characterized by dynamic light scattering, scanning electron microscopy, and atomic force microscopy techniques.

Polyvinylpyrrolidone K-30-Based Crosslinked Fast Swelling Nanogels: An Impeccable Approach for Drug's Solubility Improvement.

Poor solubility is a global issue of copious pharmaceutical industries as large number of drugs in development stage as well as already marketed products are poorly soluble which results in low dissolution and ultimately dosage increase. Current study is aimed at developing a polyvinylpyrrolidone- (PVP-K30-) based nanogel delivery system for solubility enhancement of poorly soluble drug olanzapine (OLP), as solubilization enhancement is the most noteworthy application of nanosystems. Crosslinking polymerization with subsequent condensation technique was used for the synthesis of nanogels, a highly responsive polymeric networks in drug's solubility. Developed nanogels were characterized by percent entrapment efficiency, sol-gel, percent swelling, percent drug loaded content (%DLC), percent porosity, stability, solubility, in vitro dissolution studies, FTIR, XRD, and SEM analysis. Furthermore, cytotoxicity study was conducted on rabbits to check the biocompatibility of the system. Particle size of nanogels was found with 178.99 ± 15.32 nm, and in vitro dissolution study exhibited that drug release properties were considerably enhanced as compared to the marketed formulation OLANZIA. The solubility studies indicated that solubility of OLP was noticeably improved up to 36.7-fold in phosphate buffer of pH 6.8. In vivo cytotoxicity study indicated that prepared PVP-K30-based formulation was biocompatible. On the basis of results obtained, the developed PVP-K30-co-poly (AMPS) nanogel delivery system is expected to be safe, effective, and cost-effective for solubility improvement of poorly soluble drugs.

Controlling Size and Surface Chemistry of Cationic Nanogels by Inverse Microemulsion ATRP

AbstractThe unique properties of cationic nanogels, such as their hydrophilicity and high loading capacity, make them a promising platform as drug delivery agents, particularly for the delivery of hydrophilic biomolecules. Although several synthetic methods exist for cationic nanogels, polymerization in dispersed media is advantageous due to its ability to provide control over composition and high monomer conversion. However, polymer droplets typically suffer from a significant increase in size during polymerization due to the Ostwald ripening process. Herein, the preparation of cationic nanogels by atom transfer radical polymerization under inverse microemulsion conditions of a hydrophilic inimer that prevents monomer diffusion and hence limits droplets’ growth during polymerization is reported. Additionally, the surface functionality of the nanogels can be modulated by the application of hydrophobic reactive surfactants or by grafting hydrophilic shells to form core‐shell cationic nanogels. The synthesized cationic nanogels are biocompatible, internalized to HEK 293 cells, and have a high complexation ability for plasmid DNA.

Producing submicron chitosan-stabilized oil Pickering emulsion powder by an electrostatic collector-equipped spray dryer

Chitosan (CS) was modified with two fatty acids, i.e., capric acid (CA) and palmitic acid (PA). Particle size (315.8 nm), zeta potential (31.8 mV), and viscosity (29.4 mPa.s) of CS-PA nanogels were lower than CS-CA nanogels (793.2 nm, 53.3 mV, and 70.7 mPa.s). First, hempseed oil-in-water Pickering nanoemulsions were stabilized by CS-based particles/maltodextrin (MD). Then, the emulsions were dried using an electrostatic collector-equipped spray dryer. The D50 of re-dispersed emulsion powders with CS-PA/MD coating was 936 nm. According to the FE-SEM images, oil coated with CS-PA/MD showed higher porosity and C/O ratio at the particle surface compared to the CS-CA/MD coating leading to more oil leakage. In addition, the crystallinity of hempseed oil coated with CS-PA/MD was higher than the one coated with CS-CA/MD. These findings showed that submicron Pickering emulsion powders could be achieved by targeted modification of CS and using a spray dryer equipped with an electrostatic collector.

A Protein-Like Nanogel for Spinning Hierarchically Structured Artificial Spider Silk.

Spider dragline silk is draw-spun from soluble, β-sheet-crosslinked spidroin in aqueous solution. This spider silk has an excellent combination of strength and toughness, which originates from the hierarchical structure containing β-sheet crosslinking points, spiral nanoassemblies, a rigid sheath, and a soft core. Inspired by the spidroin structure and spider spinning process, a soluble and crosslinked nanogel is prepared and crosslinked fibers are drew spun with spider-silk-like hierarchical structures containing cross-links, aligned nanoassemblies, and sheath-core structures. Introducing nucleation seeds in the nanogel solution, and applying prestretch and a spiral architecture in the nanogel fiber, further tunes the alignment and assembly of the polymer chains, and enhances the breaking strength (1.27GPa) and toughness (383MJ m-3 ) to approach those of the best dragline silk. Theoretical modeling provides understanding for the dependence of the fiber's spinning capacity on the nanogel size. This work provides a new strategy for the direct spinning of tough fiber materials.

Accurate assembly and direct characterization of DNA nanogels crosslinked by G-quadruplex, i-motif and duplex with surface-enhanced Raman spectroscopy

The direct characterization of DNA nanogels at the atomic level is desirable and of great significance, however, has been challenging because of structural complexity and the larger size of nanogels. Herein, we demonstrated a simple, sensitive and reliable SERS (Surface-enhanced Raman spectroscopy)-based approach towards direct monitoring microstructures, such as three types of nanogels crosslinked by DNA G-quadruplex, i-motif and GC duplex. The achievement is attributed to the detection of featured Raman bands corresponding to the formation of Watson-Crick and Hoogsteen hydrogen bonds as well as C·C+ base pairs. Importantly, this work reveals that the silver nanoparticles attaching on the surface of nanogels can form local ‘hotspots’ and produce high-quality of Raman spectra under the assistance of iodide, aluminum ions and dichloromethane, therefore, shows great potential for wide applications in accurate characterization of various DNA nanostructures.

Effect of environmental factors on the emulsion polymerization of nanogels

Emulsion polymerization techniques have been identified as the potential synthetic methods for the preparation of polymer nanogels. Poly(2-diisopropylaminoethyl meth-acrylate) (PDPA) nanogels were prepared via emulsion polymerization in the presence of surfactants. The effects of different parameters (e.g., monomer and surfactant content, crosslinker, initiator, and pH) on nanogel size were investigated. By controlling these factors, the monodispersed nanogels with desired-size could be obtained. This study could shed light on future applications of the nanogels and the further developments of highly interesting concepts, and further promotes the development of controlled drug release, tissue engineering, and regenerative medicine.

Regulated Polyelectrolyte Nanogels for Enzyme Encapsulation and Activation.

Polyelectrolyte (PE) nanogels consisting of cross-linked PE networks integrate the advanced features of both nanogels and PEs. The soft environment and abundant intrinsic charges are of special interest for enzyme immobilization. However, the crucial factors that regulate enzyme encapsulation and activation remain obscure to date. Herein, we synthesized cationic poly (dimethyl aminoethyl methacrylate), PDMAEMA, nanogels with well-defined size and cross-link degrees and fully investigated the effects of different control factors on lipase immobilization. We demonstrate that the cationic PDMAEMA nanogels indeed enable efficient and safe loading of anionic lipase without disturbing their structures. Strong charge interaction achieved by tuning pH and larger particle size are favorable for lipase loading, while the enhanced enzymatic activity demands nanogels with smaller size and a moderate cross-link degree. As such, PDMAEMA nanogels with a hydrodynamic radius of 35 nm and 30% cross-linker fraction display the optimal catalytic efficiency, which is fourfold of that of free lipase. Moreover, the immobilization endows enhanced enzymatic activity in a broad scope of pH, ionic strength, and temperature, demonstrating effective protection and activation of lipase by the designed nanogels. Our study validates the crucial controls of the size and structure of PE nanogels on enzyme encapsulation and activation, and the revealed findings shall be helpful for designing functional PE nanogels and boosting their applications for enzyme immobilization.

Peptide-Based Hydrogels and Nanogels for Delivery of Doxorubicin.

IntroductionThe clinical use of the antitumoral drug doxorubicin (Dox) is reduced by its dose-limiting toxicity, related to cardiotoxic side effects and myelosuppression. In order to overcome these drawbacks, here we describe the synthesis, the structural characterization and the in vitro cytotoxicity assays of hydrogels (HGs) and nanogels (NGs) based on short peptide sequences loaded with Dox or with its liposomal formulation, Doxil.MethodsFmoc-FF alone or in combination with (FY)3 or PEG8-(FY)3 peptides, at two different ratios (1/1 and 2/1 v/v), were used for HGs and NGs formulations. HGs were prepared according to the “solvent-switch” method, whereas NGs were obtained through HG submicronition by the top-down methodology in presence of TWEEN®60 and SPAN®60 as stabilizing agents. HGs gelation kinetics were assessed by Circular Dichroism (CD). Stability and size of NGs were studied using Dynamic Light Scattering (DLS) measurements. Cell viability of empty and filled Dox HGs and NGs was evaluated on MDA-MB-231 breast cancer cells. Moreover, cell internalization of the drug was evaluated using immunofluorescence assays.ResultsDox filled hydrogels exhibit a high drug loading content (DLC=0.440), without syneresis after 10 days. Gelation kinetics (20–40 min) and the drug release (16–28%) over time of HGs were found dependent on relative peptide composition. Dox filled NGs exhibit a DLC of 0.137 and a low drug release (20–40%) after 72 h. Empty HGs and NGs show a high cell viability (>95%), whereas Dox loaded ones significantly reduce cell viability after 24 h (49–57%) and 72 h (7–25%) of incubation, respectively. Immunofluorescence assays evidenced a different cell localization for Dox delivered through HGs and NGs with respect to the free drug.DiscussionA modulation of the Dox release can be obtained by changing the ratios of the peptide components. The different cellular localization of the drug loaded into HGs and NGs suggests an alternative internalization mechanism. The high DLC, the low drug release and preliminary in vitro results suggest a potential employment of peptide-based HGs and NGs as drug delivery tools.

FORMULATION AND ANTIOXIDANT ACTIVITY OF NANO GEL ETHANOL EXTRACT OF KEPOK BANANA PEEL (MUSA X PARADISIACA L.)

Kepok banana peel (Musa x paradisiaca L.) contains flavonoids that act as antioxidants. The antioxidant activity of the ethanol extract of Kepok banana peel can be used as an active ingredient of nano gel. Nano-sized preparations can increase the efficiency of the delivery of active ingredients with lesser side effects and also decrease the stratum corneum to make it easier to penetrate. The objectives of this study were to determine whether the ethanol extract of Kepok banana peel (Musa x paradisiaca L.) can be formulated as nano gel and to measure its antioxidant activity. The method of nano gel preparation was stirring technique by using a magnetic stirrer and a sonicator. The antioxidant activity was measured using DPPH method. The results showed that the ethanol extract of kepok banana peel could be formulated as nano gel with size F0 = 161.9 nm; F1 = 171.3 nm; F2 = 165.6 nm; F3 = 163.9 nm which fulfilled the nano gel size requirement (20-200 nm) and the potential zeta value F0 = -43.4 mV; F1 = -43.7 mV; F2 = -46.9 mV; F3 = -47.0 mV fulfilled the requirements (smaller than -30 mV and greater than +30 mV). The antioxidant activity showed that the IC50 of ethanol extract of was stronger than IC50 of 1% nano gel (198.0279 µg/ml : 282.8933 µg/ml).