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15 pages, 3026 KiB

Open AccessArticle

Structural, Thermal, and Release Properties of Hybrid Materials Based on Layered Zinc Hydroxide and Caffeic Acid

by Christhy V. Ruiz, María E. Becerra and Oscar Giraldo

Nanomaterials 2020, 10(1), 163; https://doi.org/10.3390/nano10010163 - 17 Jan 2020

Cited by 9 | Viewed by 3336

Abstract

Caffeic acid (CA) molecules were immobilized in a layered inorganic host matrix based on zinc hydroxide structures with different starting interlayer anions, nitrate, and acetate. The chemical composition, structure, thermal stability, morphology, and surface of the host matrices and hybrid compounds were analyzed [...] Read more.

Caffeic acid (CA) molecules were immobilized in a layered inorganic host matrix based on zinc hydroxide structures with different starting interlayer anions, nitrate, and acetate. The chemical composition, structure, thermal stability, morphology, and surface of the host matrices and hybrid compounds were analyzed by X-ray diffraction (XRD), themogravimetric/differencial thermal analysis (TG/DTA), Fourier transform infrarred spectroscopy (FT-IR), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Additionally, the surface charge of the materials was investigated using zeta potential at pH ~7. The results show an influence of the surface charge on the chemical, interaction, and structure of the resulting hybrid materials as a function of the starting layered structures. An expansion of the basal spacing to 10.20 Å for zinc hydroxide nitrate (ZHN), and a shrinkage to 10.37 Å for zinc hydroxide acetate (ZHA). These results suggest that the CA lies with a tilt angle in the interlayer region of the inorganic host matrix. The immobilization of CA is favored in ZHN, with respect to ZHA, because a single-layered phase was identified. A higher thermal stability at 65 °C was observed for ZHN-CA than for ZHA-CA. The evaluation of the release behavior showed a higher percentage of CA released from ZHN than ZHA, and the release mechanism was described by the Elovich model. The hybrid materials show potential characteristics for use as bioactive delivery systems. Full article

(This article belongs to the Special Issue Nanostructured Materials and Natural Extract)

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13 pages, 1627 KiB

Open AccessArticle

Antibacterial and Antioxidant Potential of Silver Nanoparticles Biosynthesized Using the Spruce Bark Extract

by Corneliu Tanase, Lavinia Berta, Năstaca Alina Coman, Ioana Roșca, Adrian Man, Felicia Toma, Andrei Mocan, Alexandru Nicolescu, László Jakab-Farkas, Domokos Biró and Anca Mare

Nanomaterials 2019, 9(11), 1541; https://doi.org/10.3390/nano9111541 - 30 Oct 2019

Cited by 56 | Viewed by 4307

Abstract

Biosynthesized silver nanoparticles (AgNPs) are widely used in Pharmacy and Medicine. In particular, AgNPs synthesized and mediated by plant extracts have shown topossess several biological activities. In the present study, AgNPs were synthesized using Picea abies L. stem bark extract as reducing agent. [...] Read more.

Biosynthesized silver nanoparticles (AgNPs) are widely used in Pharmacy and Medicine. In particular, AgNPs synthesized and mediated by plant extracts have shown topossess several biological activities. In the present study, AgNPs were synthesized using Picea abies L. stem bark extract as reducing agent. Factors, such as metal ion solution, pH, and time, which play a role in the AgNPs synthesis, were assessed. The synthesized AgNPs were characterized by Ultraviolet-Visible Spectrometry, Fourier transform infrared spectroscopy, and Transmission Electron Microscopy (TEM). Further, the study has been extended to evaluate the antimicrobial and antioxidant activity of AgNPs. The broad peak obtained at 411–475 nm (UV-Vis spectroscopy), and the color change pattern, confirmed the synthesis of AgNPs. TEM results showed spherical or rarely polygonal AgNPs with an average size of 44 nm at pH = 9. The AgNPs showed antioxidant activity and antibacterial effect against human pathogenic Gram-positive and Gram-negative bacteria. The results show that spruce bark extract is suitable for obtaining AgNPs, with antibacterial and antioxidant activity. Full article

(This article belongs to the Special Issue Nanostructured Materials and Natural Extract)

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11 pages, 6567 KiB

Open AccessArticle

Colorimetric Determination of the Activity of Starch-Debranching Enzyme via Modified Tollens’ Reaction

by Ke Luo, Nack-geun Kim, Sang-Mook You and Young-Rok Kim

Nanomaterials 2019, 9(9), 1291; https://doi.org/10.3390/nano9091291 - 10 Sep 2019

Cited by 18 | Viewed by 6540

Abstract

Nelson–Somogyi and 3,5-dinitrosalicylic acid (DNS) assays are the classical analytical methods for the determination of activity of starch-debranching enzymes, however, they have a narrow detection range and do not adapt to the quantitative measurement of linear polysaccharides. Herein, we developed a simple and [...] Read more.

Nelson–Somogyi and 3,5-dinitrosalicylic acid (DNS) assays are the classical analytical methods for the determination of activity of starch-debranching enzymes, however, they have a narrow detection range and do not adapt to the quantitative measurement of linear polysaccharides. Herein, we developed a simple and accurate colorimetric assay for determining the activity of starch-debranching pullulanase through the modified Tollens’ reaction in combination with UV irradiation. Silver nanoparticles (AgNPs) were formed by reducing aldehyde groups in short-chain glucans (SCGs) generated by debranching of waxy maize starch using pullulanase through the modified Tollens’ reaction. In addition to providing a reducing moiety to the Tollens’ reaction, the debranching product, SCGs, also enhanced the colloidal stability of synthesized AgNPs, of which the amplitude of its surface plasmon resonance (SPR) absorbance peak was proportional to the concentration of SCGs ranging from 0.01–10 mg/mL. The detection limit of this system was 0.01 mg/mL, which was found to be 100 times higher than that of the conventional DNS assay. The purification of SCGs by recrystallization and gelatinization improved the selectivity of this colorimetric assay for debranching products, which provides a simple and accurate means of monitoring the debranching process and characterizing the activity of starch-debranching enzymes. Full article

(This article belongs to the Special Issue Nanostructured Materials and Natural Extract)

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16 pages, 1920 KiB

Open AccessArticle

Effect of pH-Responsive Charge-Conversional Polymer Coating to Cationic Reduced Graphene Oxide Nanostructures for Tumor Microenvironment-Targeted Drug Delivery Systems

by Kitae Ryu, Jaehong Park and Tae-il Kim

Nanomaterials 2019, 9(9), 1289; https://doi.org/10.3390/nano9091289 - 9 Sep 2019

Cited by 15 | Viewed by 3527

Abstract

Tumor tissue represents a slightly acidic pH condition compared to normal tissue due to the accumulation of lactic acids via anaerobic metabolism. In this work, pH-responsive charge-conversional polymer (poly(ethylene imine)-poly(l-lysine)-poly(l-glutamic acid), PKE polymer) was employed for endowing charge-conversional property [...] Read more.

Tumor tissue represents a slightly acidic pH condition compared to normal tissue due to the accumulation of lactic acids via anaerobic metabolism. In this work, pH-responsive charge-conversional polymer (poly(ethylene imine)-poly(l-lysine)-poly(l-glutamic acid), PKE polymer) was employed for endowing charge-conversional property and serum stability to poly(ethylene imine) conjugated reduced graphene oxide-based drug delivery system (PEI-rGO). Zeta-potential value of PEI-rGO coated with PK₅E₇ polymer (PK₅E₇(PEI-rGO)) was −10.9 mV at pH 7.4 and converted to 29.2 mV at pH 6.0, showing pH-responsive charge-conversional property. Sharp-edged plate morphology of PEI-rGO was transformed to spherical nanostructures with vague edges by PK₅E₇ coating. Size of PK₅E₇(PEI-rGO) was found to be smaller than that of PEI-rGO in the serum condition, showing its increased serum stability. Loaded doxorubicin (DOX) in PK₅E₇(PEI-rGO) could be released rapidly in lysosomal condition (pH 5.0, 5 mM glutathione). Furthermore, DOX-loaded PK₅E₇(PEI-rGO) showed enhanced anticancer activity in HeLa and A549 cells in the tumor microenvironment-mimicking condition (pH 6.0, serum), which would be mediated by non-specific cellular interaction with decorated serum proteins. These results indicate that the pH-responsive charge-conversional PKE polymer coating strategy of cationic rGO nanostructures possesses a potential for acidic tumor microenvironment-targeted drug delivery systems. Full article

(This article belongs to the Special Issue Nanostructured Materials and Natural Extract)

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11 pages, 3366 KiB

Open AccessArticle

Zingiber officinale Extract (ZOE) Incorporated with Layered Double Hydroxide Hybrid through Reconstruction to Preserve Antioxidant Activity of ZOE against Ultrasound and Microwave Irradiation

by Hyoung-Jun Kim, Su-Bin Lee, Ae-Jin Choi and Jae-Min Oh

Nanomaterials 2019, 9(9), 1281; https://doi.org/10.3390/nano9091281 - 8 Sep 2019

Cited by 14 | Viewed by 3065

Abstract

We prepared Zingiber officinale extract (ZOE) incorporated in a layered double hydroxide (LDH) hybrid through a reconstruction method in order to preserve the antioxidant activity of ZOE from ultrasound and microwave irradiation. X-ray patterns, infrared spectroscopy, and scanning electron microscopy suggested that ZOE [...] Read more.

We prepared Zingiber officinale extract (ZOE) incorporated in a layered double hydroxide (LDH) hybrid through a reconstruction method in order to preserve the antioxidant activity of ZOE from ultrasound and microwave irradiation. X-ray patterns, infrared spectroscopy, and scanning electron microscopy suggested that ZOE moieties were encapsulated in the interparticle space of reconstructed LDH, thus preserving its intact structure. Dynamic light scattering and zeta-potential measurement also supported the hypothesis that ZOE moieties were located in the interparticle pore of LDH rather than at the surface of LDH particles. Thermogravimetry analysis revealed that thermal stability of encapsulated ZOE could be enhanced by LDH encapsulation. Radical scavenging assay showed that antioxidant activity of ZOE–LDH hybrid was increased after ultrasound and microwave irradiation, while ZOE itself dramatically lost its antioxidant activity upon ultrasound and microwave treatment. Full article

(This article belongs to the Special Issue Nanostructured Materials and Natural Extract)

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16 pages, 2949 KiB

Open AccessArticle

Incorporation of Glycine max Merrill Extract into Layered Double Hydroxide through Ion-Exchange and Reconstruction

by Do-Gak Jeung, Hyoung-Jun Kim and Jae-Min Oh

Nanomaterials 2019, 9(9), 1262; https://doi.org/10.3390/nano9091262 - 5 Sep 2019

Cited by 20 | Viewed by 3083

Abstract

We incorporated extract of Glycine max Merrill (GM), which is generally known as soybean, into a layered double hydroxide (LDH) nanostructure through two different methods, ion-exchange and reconstruction. Through X-ray diffraction, field-emission scanning electron microscopy, and zeta-potential measurement, GM moiety seemed to be [...] Read more.

We incorporated extract of Glycine max Merrill (GM), which is generally known as soybean, into a layered double hydroxide (LDH) nanostructure through two different methods, ion-exchange and reconstruction. Through X-ray diffraction, field-emission scanning electron microscopy, and zeta-potential measurement, GM moiety seemed to be simply attached on the surface of LDH by ion-exchange process, while the extract could be incorporated in the inter-particle pore of LDHs by reconstruction reaction. The quantification exhibited that both incorporation method showed comparable extract loading capacity of 15.6 wt/wt% for GM-LDH hybrid prepared by ion-exchange (GML-I) and 18.6 wt/wt% for GM-LDH hybrid by reconstruction (GML-R). On the other hand, bioactive substance in both GM-LDH hybrids, revealed that GML-R has higher daidzein content (0.0286 wt/wt%) compared with GML-I (0.0108 wt/wt%). According to time-dependent daidzein release, we confirmed that GML-R showed pH dependent daidzein release; a higher amount of daidzein was released in pH 4.5 physiological condition than in pH 7.4, suggesting the drug delivery potential of GML-R. Furthermore, alkaline phosphatase activity and collagen fiber formation on human osteoblast-like MG-63 cells displayed that GML-R had superior possibility of osteoblast differentiation than GML-I. From these results, we concluded that reconstruction method was more effective for extract incorporation than ion-exchange reaction, due to its pH dependent release property and alkaline phosphatase activity. Full article

(This article belongs to the Special Issue Nanostructured Materials and Natural Extract)

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19 pages, 3965 KiB

Open AccessArticle

Food Additive Titanium Dioxide and Its Fate in Commercial Foods

by Ji-Soo Hwang, Jin Yu, Hyoung-Mi Kim, Jae-Min Oh and Soo-Jin Choi

Nanomaterials 2019, 9(8), 1175; https://doi.org/10.3390/nano9081175 - 16 Aug 2019

Cited by 49 | Viewed by 7288

Abstract

Titanium dioxide (TiO₂) is one of the most extensively utilized food additives (E171) in the food industry. Along with nanotechnology development, the concern about the presence of nanostructured particles in E171 TiO₂ and commercial food products is growing. In the [...] Read more.

Titanium dioxide (TiO₂) is one of the most extensively utilized food additives (E171) in the food industry. Along with nanotechnology development, the concern about the presence of nanostructured particles in E171 TiO₂ and commercial food products is growing. In the present study, the physicochemical properties of commercially available E171 TiO₂ particles, including particle size distribution, were investigated, followed by their cytotoxicity and intestinal transport evaluation. The fate determination and quantification of E171 TiO₂ in commercial foods were carried out based on the analytical procedure developed using simulated foods. The results demonstrated that TiO₂ is a material mainly composed of particles larger than 100 nm, but present as an agglomerated or aggregated particle in commercial foods with amounts of less than 1% (wt/wt). Titanium dioxide particles generated reactive oxygen species and inhibited long-term colony formation, but the cytotoxicity was not related to particle size distribution or particle type (food- or general-grade). All TiO₂ particles were mainly transported by microfold (M) cells, but also by intestinal tight junction. These findings will be useful for TiO₂ application in the food industry and predicting its potential toxicity. Full article

(This article belongs to the Special Issue Nanostructured Materials and Natural Extract)

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15 pages, 1932 KiB

Open AccessArticle

Novel LDPE/Chitosan Rosemary and Melissa Extract Nanostructured Active Packaging Films

by Aris Giannakas, Constantinos Salmas, Areti Leontiou, Dimitrios Tsimogiannis, Antigoni Oreopoulou and Joerg Braouhli

Nanomaterials 2019, 9(8), 1105; https://doi.org/10.3390/nano9081105 - 1 Aug 2019

Cited by 30 | Viewed by 4723

Abstract

The increased global market trend for food packaging is imposing new improved methods for the extension of shelf-life and quality of food products. Active packaging, which is based on the incorporation of additives into packaging materials, is becoming significant for this purpose. In [...] Read more.

The increased global market trend for food packaging is imposing new improved methods for the extension of shelf-life and quality of food products. Active packaging, which is based on the incorporation of additives into packaging materials, is becoming significant for this purpose. In this work, nanostructured low-density polyethylene (LDPE) was combined with chitosan (CS) to aim for a food packaging development with an increased oxygen permeability barrier and higher antimicrobial activity. Furthermore, essential oil extracts as rosemary (RO) and Melissa (MO) were added to this packaging matrix in order to improve its antioxidant properties and vanish food odor problems. The novel nanostructured active packaging film was tested using laboratory instrumental methods, such as thermogravimetry (TG), Fourier-transform infrared (FTIR) spectrometry, the X-ray diffraction (XRD) method, a dilatometer for tensile properties (DMA), and an oxygen permeation analyzer (OPA). Moreover, laboratorian tests according to ASTM standards were carried out for the estimation of water sorption, water vapor permeability, overall migration, and, finally, the antioxidant properties of such films. The experimental results have indicated that the final material exhibits advanced properties. More specifically, chitosan addition was observed to lead to an enhanced oxygen and water-vapor permeability barrier while the extracted essential oil addition led to enhanced tensile strength and antioxidant properties. Full article

(This article belongs to the Special Issue Nanostructured Materials and Natural Extract)

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18 pages, 3090 KiB

Open AccessArticle

Preparation and Characterization of Self Nano-Emulsifying Drug Delivery System Loaded with Citraland Its Antiproliferative Effect on Colorectal Cells In Vitro

by Mira Nadiah Mohd Izham, Yazmin Hussin, Muhammad Nazirul Mubin Aziz, Swee Keong Yeap, Heshu Sulaiman Rahman, Mas Jaffri Masarudin, Nurul Elyani Mohamad, Rasedee Abdullah and Noorjahan Banu Alitheen

Nanomaterials 2019, 9(7), 1028; https://doi.org/10.3390/nano9071028 - 18 Jul 2019

Cited by 63 | Viewed by 6598

Abstract

Citral is an active compound naturally found in lemongrass, lemon, and lime. Although this pale-yellow liquid confers low water solubility, the compound has been reported to possess good therapeutic features including antiproliferative and anticancer modalities. The self nano-emulsifying drug delivery system (SNEDDS) is [...] Read more.

Citral is an active compound naturally found in lemongrass, lemon, and lime. Although this pale-yellow liquid confers low water solubility, the compound has been reported to possess good therapeutic features including antiproliferative and anticancer modalities. The self nano-emulsifying drug delivery system (SNEDDS) is a type of liquid-lipid nanocarrier that is suitable for the loading of insolubilized oil-based compound such as Citral. This study reports the design and optimization of a SNEDDS formulation, synthesis and characterization as well as loading with Citral (CIT-SNEDDS). Further assessment of theantiproliferative effects of CIT-SNEDDS towards colorectal cancer cells was also conducted. SNEDDS composed of coconut oil, dimethyl sulfoxide (DMSO) and Tween 80. CIT-SNEDDS was prepared via gentle agitation of SNEDDS with 0.5% Citral for 72 h at room temperature. Physicochemical characterization was performed using several physicochemical analyses. The average particle size of CIT-SNEDDS was16.86 ± 0.15 nm, zeta potential of 0.58 ± 0.19 mV, and polydispersity index (PDI) of 0.23 ± 0.01. In vitro drug release of Citral from CIT-SNEDDS was 79.25% of release, and for Citral the release percentage was 93.56% over 72 h. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was done to determine the cytotoxicity effect of CIT-SNEDDS in human colorectal cancer cell lines HT29 and SW620. The half maximal inhibitory concentrations (IC₅₀) for 72 hof CIT-SNEDDS and Citral on SW620 were 16.50 ± 0.87 µg/mL and 22.50 ± 2.50 µg/mL, respectively. The IC₅₀ values of CIT-SNEDDS and Citral after 72 h of treatment on HT29 were 34.10 ± 0.30 µg/mL and 21.77 ± 0.23 µg/mL, respectively. This study strongly suggests that CIT-SNEDDS has permitted the sustained release of Citral and that CIT-SNEDDS constitutes a potential soluble drug nanocarrier that is effective against colorectal cancer cells. Full article

(This article belongs to the Special Issue Nanostructured Materials and Natural Extract)

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16 pages, 21754 KiB

Open AccessArticle

Sesquiterpenoids from Tussilago farfara Flower Bud Extract for the Eco-Friendly Synthesis of Silver and Gold Nanoparticles Possessing Antibacterial and Anticancer Activities

by You Jeong Lee, Kwangho Song, Song-Hyun Cha, Seonho Cho, Yeong Shik Kim and Youmie Park

Nanomaterials 2019, 9(6), 819; https://doi.org/10.3390/nano9060819 - 31 May 2019

Cited by 38 | Viewed by 4715

Abstract

Sesquiterpenoids from the flower bud extract of Tussilago farfara were effectively utilized as a reducing agent for eco-friendly synthesis of silver and gold nanoparticles. The silver and gold nanoparticles had a characteristic surface plasmon resonance at 416 nm and 538 nm, respectively. Microscopic [...] Read more.

Sesquiterpenoids from the flower bud extract of Tussilago farfara were effectively utilized as a reducing agent for eco-friendly synthesis of silver and gold nanoparticles. The silver and gold nanoparticles had a characteristic surface plasmon resonance at 416 nm and 538 nm, respectively. Microscopic images revealed that both nanoparticles were spherical, and their size was measured to be 13.57 ± 3.26 nm for the silver nanoparticles and 18.20 ± 4.11 nm for the gold nanoparticles. The crystal structure was determined to be face-centered cubic by X-ray diffraction. Colloidal stability of the nanoparticle solution was retained in a full medium, which was used in the cell culture experiment. The antibacterial activity result demonstrated that the silver nanoparticles showed better activity (two- to four-fold enhancement) than the extract alone on both Gram-positive and Gram-negative bacteria. Interestingly, the highest antibacterial activity was obtained against vancomycin-resistant Enterococci Van-A type Enterococcus faecium. Cytotoxicity on cancer cell lines confirmed that gold nanoparticles were more cytotoxic than silver nanoparticles. The highest cytotoxicity was observed on human pancreas ductal adenocarcinoma cells. Therefore, both nanoparticles synthesized with the sesquiterpenoids from T. farfara flower bud extract can be applicable as drug delivery vehicles of anticancer or antibacterial agents for future nanomedicine applications. Full article

(This article belongs to the Special Issue Nanostructured Materials and Natural Extract)

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Review

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21 pages, 4498 KiB

Open AccessReview

Functional Layered Double Hydroxide Nanohybrids for Biomedical Imaging

by Wenji Jin and Dae-Hwan Park

Nanomaterials 2019, 9(10), 1404; https://doi.org/10.3390/nano9101404 - 2 Oct 2019

Cited by 28 | Viewed by 4525

Abstract

Biomedical investigations using layered double hydroxide (LDH) nanoparticles have attracted tremendous attentions due to their advantages such as biocompatibility, variable-chemical compositions, anion-exchange capacity, host–guest interactions, and crystallization-dissolution characters. Bio-imaging becomes more and more important since it allows theranostics to combine therapy and diagnosis, [...] Read more.

Biomedical investigations using layered double hydroxide (LDH) nanoparticles have attracted tremendous attentions due to their advantages such as biocompatibility, variable-chemical compositions, anion-exchange capacity, host–guest interactions, and crystallization-dissolution characters. Bio-imaging becomes more and more important since it allows theranostics to combine therapy and diagnosis, which is a concept of next-generation medicine. Based on the unique features mentioned above, LDHs create novel opportunities for bio-imaging and simultaneous therapy with LDHs-based nanohybrids. This review aims to explore the recent advances in multifunctional LDH nanohybrids ranging from synthesis to practical applications for various bio-imaging with therapeutic functions. Furthermore, their potential both as diagnostic agents and drug delivery carriers will be discussed with the improvement in noninvasive bio-imaging techniques. Full article

(This article belongs to the Special Issue Nanostructured Materials and Natural Extract)

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