Sparking Nano-Metals on a Surface of Polyethylene Terephthalate and Its Application: Anti-Coronavirus and Anti-Fogging Properties.

The nano-metal-treated PET films with anti-virus and anti-fogging ability were developed using sparking nano-metal particles of Ag, Zn, and Ti wires on polyethylene terephthalate (PET) films. Ag nanoparticles were detected on the PET surface, while a continuous aggregate morphology was observed with Zn and Ti sparking. The color of the Ag-PET films changed to brown with increasing repeat sparking times, but not with the Zn-PET and Ti-PET films. The water contact angle of the nano-metal-treated PET films decreased with increasing repeat sparking times. The RT-PCR anti-virus test confirmed the high anti-virus efficiency of the nano-metal-treated PET films due to the fine particle distribution, high polarity, and binding of the nano-metal ions to the coronavirus, which was destroyed by heat after UV irradiation. A highly transparent, anti-fogging, and anti-virus face shield was prepared using the Zn-PET film. Sparking was an effective technique to prepare the alternative anti-virus and anti-fogging films for medical biomaterial applications because of their low cost, convenience, and fast processing.

Formulation and Characterization of Nicotine Microemulsion-Loaded Fast-Dissolving Films for Smoking Cessation.

The present study aimed to develop a nicotine microemulsion (NCT-ME) and incorporate it into a fast-dissolving film. The NCT-ME was prepared by mixing the specified proportions of nicotine (NCT), surfactant, co-solvent, and water. The NCT-ME was measured by its average droplet size, size distribution, zeta potential, and morphology. NCT-ME fast-dissolving films were prepared by the solvent casting technique. The films were characterized by morphology, weight, thickness, disintegration time, and mechanical strength properties and the determined NCT loading efficiency and in vitro drug release. The results showed that almost all NCT-MEs presented droplet sizes of less than 100 nm with a spherical form, narrow size distribution, and zeta potentials of -10.6 to -73.7 mV. There was no difference in weight and thickness between all NCT-ME films, but significant changes in the disintegration times were noticed in NCT40-Smix[PEG-40H(2:1)]10 film. The mechanical properties of films varied with changes in type of surfactant. About 80% of the drug release was observed to be between 3 and 30 min. The drug release kinetics were fitted with the Higuchi matrix model. The NCT40-Smix[P-80(1:1)]10 film showed the highest dissolution rate. It was concluded that the developed ME-loaded fast-dissolving film can increase drug release to a greater extent than the films without ME.

Mass Spectrometry-Based Metabolomics of Phytocannabinoids from Non-Cannabis Plant Origins.

Phytocannabinoids are isoprenylated resorcinyl polyketides produced mostly in glandular trichomes of Cannabis sativa L. These discoveries led to the identification of cannabinoid receptors, which modulate psychotropic and pharmacological reactions and are found primarily in the human central nervous system. As a result of the biogenetic process, aliphatic ketide phytocannabinoids are exclusively found in the cannabis species and have a limited natural distribution, whereas phenethyl-type phytocannabinoids are present in higher plants, liverworts, and fungi. The development of cannabinomics has uncovered evidence of new sources containing various phytocannabinoid derivatives. Phytocannabinoids have been isolated as artifacts from their carboxylated forms (pre-cannabinoids or acidic cannabinoids) from plant sources. In this review, the overview of the phytocannabinoid biosynthesis is presented. Different non-cannabis plant sources are described either from those belonging to the angiosperm species and bryophytes, together with their metabolomic structures. Lastly, we discuss the legal framework for the ingestion of these biological materials which currently receive the attention as a legal high.

In Vitro and In Vivo Regulation of SRD5A mRNA Expression of Supercritical Carbon Dioxide Extract from Asparagus racemosus Willd. Root as Anti-Sebum and Pore-Minimizing Active Ingredients.

Oily skin from overactive sebaceous glands affects self-confidence and personality. There is report of an association between steroid 5-alpha reductase gene (SRD5A) expression and facial sebum production. There is no study of the effect of Asparagus racemosus Willd. root extract on the regulation of SRD5A mRNA expression and anti-sebum efficacy. This study extracted A. racemosus using the supercritical carbon dioxide fluid technique with ethanol and investigated its biological compounds and activities. The A. racemosus root extract had a high content of polyphenolic compounds, including quercetin, naringenin, and p-coumaric acid, and DPPH scavenging activity comparable to that of the standard L-ascorbic acid. A. racemosus root extract showed not only a significant reduction in SRD5A1 and SRD5A2 mRNA expression by about 45.45% and 90.86%, respectively, but also a reduction in the in vivo anti-sebum efficacy in male volunteers, with significantly superior percentage changes in facial sebum production and a reduction in the percentages of pore area after 15 and 30 days of treatment. It can be concluded that A. racemosus root extract with a high content of polyphenol compounds, great antioxidant effects, promising downregulation of SRD5A1 and SRD5A2, and predominant facial sebum reduction and pore-minimizing efficacy could be a candidate for an anti-sebum and pore-minimizing active ingredient to serve in functional cosmetic applications.

Morphology, Mechanical, and Water Barrier Properties of Carboxymethyl Rice Starch Films: Sodium Hydroxide Effect.

Carboxymethyl rice starch films were prepared from carboxymethyl rice starch (CMSr) treated with sodium hydroxide (NaOH) at 10-50% w/v. The objective of this research was to determine the effect of NaOH concentrations on morphology, mechanical properties, and water barrier properties of the CMSr films. The degree of substitution (DS) and morphology of native rice starch and CMSr powders were examined. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) were used to investigate the chemical structure, crystallinity, and thermal properties of the CMSr films. As the NaOH concentrations increased, the DS of CMSr powders increased, which affected the morphology of CMSr powders; a polyhedral shape of the native rice starch was deformed. In addition, the increase in NaOH concentrations of the synthesis of CMSr resulted in an increase in water solubility, elongation at break, and water vapor permeability (WVP) of CMSr films. On the other hand, the water contact angle, melting temperature, and the tensile strength of the CMSr films decreased with increasing NaOH concentrations. However, the tensile strength of the CMSr films was relatively low. Therefore, such a property needs to be improved and the application of the developed films should be investigated in the future work.

Extraction of Tropical Fruit Peels and Development of HPMC Film Containing the Extracts as an Active Antibacterial Packaging Material.

In recent years, instead of the use of chemical substances, alternative substances, especially plant extracts, have been characterized for an active packaging of antibacterial elements. In this study, the peels of mangosteen (Garcinia mangostana), rambutan (Nephelium lappaceum), and mango (Mangifera indica) were extracted to obtain bioactive compound by microwave-assisted extraction (MAE) and maceration with water, ethanol 95% and water-ethanol (40:60%). All extracts contained phenolics and flavonoids. However, mangosteen peel extracted by MAE and maceration with water/ethanol (MT-MAE-W/E and MT-Ma-W/E, respectively) contained higher phenolic and flavonoid contents, and exhibited greater antibacterial activity against Staphylococcus aureus and Escherichia coli. Thus, both extracts were analyzed by liquid chromatograph-mass spectrometer (LC-MS) analysis, α-mangostin conferring antibacterial property was found in both extracts. The MT-MAE-W/E and MT-Ma-W/E films exhibited 30.22 ± 2.14 and 30.60 ± 2.83 mm of growth inhibition zones against S. aureus and 26.50 ± 1.60 and 26.93 ± 3.92 mm of growth inhibition zones against E. coli. These clear zones were wider than its crude extract approximately 3 times, possibly because the film formulation enhanced antibacterial activity with sustained release of active compound. Thus, the mangosteen extracts have potential to be used as an antibacterial compound in active packaging.

High Substitution Synthesis of Carboxymethyl Chitosan for Properties Improvement of Carboxymethyl Chitosan Films Depending on Particle Sizes.

This study investigated the effect of chitosan particle sizes on the properties of carboxymethyl chitosan (CMCh) powders and films. Chitosan powders with different particle sizes (75, 125, 250, 450 and 850 µm) were used to synthesize the CMCh powders. The yield, degree of substitution (DS), and water solubility of the CMCh powders were then determined. The CMCh films prepared with CMCh based on chitosan with different particle sizes were fabricated by a solution casting technique. The water solubility, mechanical properties, and water vapor transmission rate (WVTR) of the CMCh films were measured. As the chitosan particle size decreased, the yield, DS, and water solubility of the synthesized CMCh powders increased. The increase in water solubility was due to an increase in the polarity of the CMCh powder, from a higher conversion of chitosan into CMCh. In addition, the higher conversion of chitosan was also related to a higher surface area in the substitution reaction provided by chitosan powder with a smaller particle size. As the particle size of chitosan decreased, the tensile strength, elongation at break, and WVTR of the CMCh films increased. This study demonstrated that a greater improvement in water solubility of the CMCh powders and films can be achieved by using chitosan powder with a smaller size.

The Cannabis Terpenes.

Terpenes are the primary constituents of essential oils and are responsible for the aroma characteristics of cannabis. Together with the cannabinoids, terpenes illustrate synergic and/or entourage effect and their interactions have only been speculated in for the last few decades. Hundreds of terpenes are identified that allude to cannabis sensory attributes, contributing largely to the consumer's experiences and market price. They also enhance many therapeutic benefits, especially as aromatherapy. To shed light on the importance of terpenes in the cannabis industry, the purpose of this review is to morphologically describe sources of cannabis terpenes and to explain the biosynthesis and diversity of terpene profiles in different cannabis chemovars.

Enhancement of anti-inflammatory activity of polyphenolic flavonoid rutin by encapsulation.

The cellular mechanisms underlying the anti-inflammatory activity of rutin which has been found to have in vivo inhibitory effects merit more evaluation. The effects of rutin and encapsulated-rutin on lipopolysaccharide (LPS)-induced IL-6 secretion, NF-κB expression, as well as protein denaturation were investigated. The secretion of IL-6 was not found to have significantly reduced upon incubation with either rutin or encapsulated-rutin at all concentrations. At 100 µg/mL, the cells treated with encapsulated-rutin brought about slightly reduced IL-6 secretion but significantly inhibited NF-kB protein expression and protein denaturation in comparison with rutin. Inflammation can be resolved through many mechanisms. The inhibition of IL-6 and NF-kB can serve not only to terminate inflammation but also to inhibit other cytokines or mechanisms. Further investigations are necessary to clarify, verify and establish the anti-inflammatory mechanisms of rutin. Additionally, the encapsulation is an interesting technique for enhancing rutin activity.

Determination of vat-photopolymerization parameters for microneedles fabrication and characterization of HPMC/PVP K90 dissolving microneedles utilizing 3D-printed mold.

Three-dimensional (3D) printing serves as an alternative method for fabricating microneedle (MN) patches with a high object resolution. In this investigation, four distinct needle shapes: pyramid mounted over a long cube (shape A), cone mounted over a cylinder (shape B), pyramidal shape (shape C), and conical shape (shape D) were designed using computer-aided design (CAD) software with compensated bases of 350, 450 and 550 µm. Polylactic acid (PLA) biophotopolymer resin from eSun and stereolithography (SLA) 3D printer from Anycubic technology were used to print MN patches. The 3D-printed MN patches were employed to construct MN molds, and those molds were used to produce hydroxypropyl methylcellulose (HPMC) and polyvinyl pyrrolidone (PVP) K90 dissolving microneedles (DMNs). Various printing parameters, such as curing time, printing angle, and anti-aliasing (AA), were varied to evaluate suitable printing conditions for each shape. Furthermore, physical appearance, mechanical property, and skin insertion ability of HPMC/PVP K90 DMNs were examined. The results showed that for shape A and C, the suitable curing time and printing angle were 1.5 s and 30° while for shapes B and D, they were 2.0 s and 45°, respectively. All four shapes required AA to eliminate their stair-stepped edges. Additionally, it was demonstrated that all twelve designs of 3D-printed MN patches could be employed for fabricating MN molds. HPMC/PVP K90 DMNs with the needles of shape A and B exhibited better physicochemical properties compared to those of shape C and D. Particularly, both sample 9 and 10 displayed sharp needle without bent tips, coupled with minimal height reduction (< 10%) and a high percentage of blue dots (approximately 100%). As a result, 3D printing can be utilized to custom construct 3D-printed MN patches for producing MN molds, and HPMC/PVP K90 DMNs manufactured by those molds showed excellent physicochemical properties.

HPMC/PVP K90 Dissolving Microneedles Fabricated from 3D-Printed Master Molds: Impact on Microneedle Morphology, Mechanical Strength, and Topical Dissolving Property.

Three-dimensional (3D) printing can be used to fabricate custom microneedle (MN) patches instead of the conventional method. In this work, 3D-printed MN patches were utilized to fabricate a MN mold, and the mold was used to prepare dissolving MNs for topical lidocaine HCl (L) delivery through the skin. Topical creams usually take 1-2 h to induce an anesthetic effect, so the delivery of lidocaine HCl from dissolving MNs can allow for a therapeutic effect to be reached faster than with a topical cream. The dissolving-MN-patch-incorporated lidocaine HCl was constructed from hydroxypropyl methylcellulose (HPMC; H) and polyvinyl pyrrolidone (PVP K90; P) using centrifugation. Additionally, the morphology, mechanical property, skin insertion, dissolving behavior, drug-loading content, drug release of MNs and the chemical interactions among the compositions were also examined. H51P2-L, H501P2-L, and H901P2-L showed an acceptable needle appearance without bent tips or a broken structure, and they had a low % height change (<10%), including a high blue-dot percentage on the skin (>80%). These three formulations exhibited a drug-loading content approaching 100%. Importantly, the composition-dependent dissolving abilities of MNs were revealed. Containing the lowest amount of HPMC in its formulation, H901P2-L showed the fastest dissolving ability, which was related to the high amount of lidocaine HCl released through the skin. Moreover, the results of an FTIR analysis showed no chemical interactions among the two polymers and lidocaine HCl. As a result, HPMC/PVP K90 dissolving microneedles can be used to deliver lidocaine HCl through the skin, resulting in a faster onset of anesthetic action.

Natural polysaccharides and their derivatives targeting the tumor microenvironment: A review.

Polysaccharides have gained attention as valuable supplements and natural medicinal resources, particularly for their anti-tumor properties. Their low toxicity and potent anti-tumor effects make them promising candidates for cancer prevention and treatment. The tumor microenvironment is crucial in tumor development and offers potential avenues for novel cancer therapies. Research indicates that polysaccharides can positively influence the tumor microenvironment. However, the structural complexity of most anti-tumor polysaccharides, often heteropolysaccharides, poses challenges for structural analysis. To enhance their pharmacological activity, researchers have modified the structure and properties of natural polysaccharides based on structure-activity relationships, and they have discovered that many polysaccharides exhibit significantly enhanced anti-tumor activity after chemical modification. This article reviews recent strategies for targeting the tumor microenvironment with polysaccharides and briefly discusses the structure-activity relationships of anti-tumor polysaccharides. It also summarises the main chemical modification methods of polysaccharides and discusses the impact of chemical modifications on the anti-tumor activity of polysaccharides. The review aims to lay a theoretical foundation for the development of anti-tumor polysaccharides and their derivatives.

A MAX phase (Ti3AlC2) as a performance enhancer for poly(lactic acid) electrospun membranes in steam generation and solar desalination.

Clean water and sanitation issues motivate researchers to develop water evaporators for freshwater generation. The composite membrane evaporator was electrospun herein based on poly(lactic acid) (PLA) and Ti3AlC2 MAX phase as a property enhancer. As a precursor for the MXenes synthesis, the MAX phase has never been explored with PLA for water evaporator potential. Alternative use of the MAX phase can reduce the production cost arising from chemical synthesis. This work explored the potential of the MAX phase as an additive to enhance PLA membrane performance for steam generation and desalination applications. Under the infrared irradiation (∼1.0 kW/m2), the mechanically-improved PLA/MAX phase membrane showed an enhanced water evaporation rate of 1.70 kg/m2 h (93.93 % efficiency), with an approximately 52 % rate increment relative to the PLA membrane. Based on the artificial seawater (3.5 % w/w), the membrane exhibited an evaporation rate of 1.60 kg/m2 h (87.57 % efficiency). The membrane showed self-floating ability at the air-water interface, excellent thermal stability over the entire operating temperatures, and reusability after repeated cycles. Moreover, the generated freshwater contained exceptionally low cations concentrations, as low as those in potable water. The developed composite membrane also had proved its potential for solar desalination in the water generation field.

Modification of a Carboxymethyl Cellulose/Poly(vinyl alcohol) Hydrogel Film with Citric Acid and Glutaraldehyde Crosslink Agents to Enhance the Anti-Inflammatory Effectiveness of Triamcinolone Acetonide in Wound Healing.

Anti-inflammatory wound healing involves targeted drug delivery to the wound site using hydrogel materials to prolong drug effectiveness. In this work, hydrogel films were fabricated using carboxymethyl cellulose (CMC) and poly(vinyl alcohol) (PVA) crosslinked with citric acid (CA) and glutaraldehyde (GA) at different concentrations. The crosslinker densities were optimized with various CA (2-10% w/v) and GA (1-5% v/v) concentrations. The optimized crosslink densities in the hydrogel exhibited additional functional group peaks in the FT-IR spectra at 1740 cm-1 for the C=O stretching of the ester linkage in CA and at 1060 cm-1 for the C-O-C stretching of the ether group in GA. Significantly, the internal porous structures of hydrogel composite films improved density, swelling capacities, solubility percentage reduction, and decreased water retention capacities with optimized crosslinker densities. Therefore, these hydrogel composite films were utilized as drug carriers for controlled drug release within 24 h during medical treatment. Moreover, the hydrogel films demonstrated increased triamcinolone acetonide (TAA) absorption with higher crosslinker density, resulting in delayed drug release and improved TAA efficiency in anti-inflammatory activity. As a result, the modified hydrogel showed the capability of being an alternative material with enhanced anti-inflammatory efficiency with hydrogel films.

Inside-out templating: A strategy to decorate helical carbon nanotubes and 2D MoS2 on ethyl cellulose sponge for enhanced oil adsorption and oil/water separation.

Ethyl cellulose (EC)-based composite sponges were developed for oil spillage treatment. The EC sponge surface was decorated with helical carbon nanotubes (HCNTs) and molybdenum disulfide (MoS2) (1 phr) using the inside-out sugar templating method. The inside surface of a sugar cube was coated with HCNTs and MoS2. After filling the sugar cube pores with EC and the subsequent sugar leaching, the decorating materials presented on the sponge surface. The EC/HCNT/MoS2 sponge had a high level of oil removal based on its adsorption capacity (41.68 g/g), cycled adsorption (∼75-79 %), separation flux efficiency (∼85-95 %), and efficiency in oil/water emulsion separation (92-94 %). The sponge maintained adsorption capacity in acidic, basic, and salty conditions, adsorbed oil under water, and functioned as an oil/water separator in a continuous pump-assisted system. The compressive stress and Young's modulus of the EC sponge increased following its decoration using HCNTs and MoS2. The composite sponge was robust based on cycled compression and was thermally stable up to ∼120 οC. Based on the eco-friendliness of EC, the low loading of HCNTs and MoS2, and sponge versatility, the developed EC/HCNT/MoS2 sponge should be good candidate for use in sustainable oil adsorption and separation applications.

Itaconic Acid Cross-Linked Biomolecule Immobilization Approach on Amine-Functionalized Silica Nanoparticles for Highly Sensitive Enzyme-Linked Immunosorbent Assay (ELISA).

Biomolecule immobilization on nanomaterials is attractive for biosensors since it enables the capture of a higher concentration of bioreceptor units while also serving as a transduction element. The technique could enhance the accuracy, specificity, and sensitivity of the analytical measurements of biomolecules. However, it was found that the limitation in chemically binding biomolecules on nanoparticle surfaces could only cross-link between the C-terminal and N-terminal. Here, we report the facile one-step synthesis of amine-functionalized silica nanoparticles (AFSNPs). (3-Aminopropyl)triethoxysilane was used as a precursor to modify the functional surface of nanoparticles via the Stöber process. The biomolecules were immobilized to the AFSNPs through itaconic acid, a novel cross-linker that binds between the N-terminal and N-terminal and potentially improves proteins and nucleic acid immobilization onto the nanoparticle surface. The newly developed immobilization approach on AFSNPs for biomolecular detection enhanced the efficiency of ELISA, resulting in increased sensitivity. It might also be easily used to identify different pathogens for clinical diagnostics.

Extraction, purification, structural characterization, and bioactivities of the genus Schisandra polysaccharides: A review.

The genus Schisandra, a member of the Magnoliaceae family, is a well-known tonic traditional Chinese medicine with a long history of traditional medicinal and functional food used in China. Polysaccharides are one of its main active constituents, which have a wide range of bioactivities, such as anti-inflammatory, anti-tumor, neuroprotection, anti-diabetes, hepatoprotection, immunomodulation, and anti-fatigue. In this paper, we review the extraction, isolation, purification, structural characterization, bioactivities, as well as structure-activity relationship of polysaccharides from the genus Schisandra. In conclusion, we hope that this review could provide reference for the subsequent research on structural, bioactivities, development and application of the genus Schisandra polysaccharides.

Biological activities of phenolic compounds and triterpenoids from the galls of Terminalia chebula.

Nine phenolic compounds, including two phenolic carboxylic acids, 1 and 2, seven hydrolyzable tannins, 3-9, eight triterpenoids, including four oleanane-type triterpene acids, 10-13, and four of their glucosides, 14-17, isolated from a MeOH extract of the gall of Terminalia chebula Retz. (myrobalan tree; Combretaceae), were evaluated for their inhibitory activities against melanogenesis in B16 melanoma cells induced by α-melanocyte-stimulating hormone (α-MSH), against the Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol 13-acetate (TPA) in Raji cells, and against TPA-induced inflammation in mice. Their 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activities and cytotoxic activities against four human cancer cell lines were also evaluated. Compounds 6-9 and 12 exhibited potent inhibitory activities against melanogenesis (39.3-66.3% melanin content) with low toxicity to the cells (74.5-105.9% cell viability) at a concentration of 10 µM. Western-blot analysis revealed that isoterchebulin (8) reduced the protein levels of MITF (=microphtalmia-associated transcription factor), tyrosinase, and TRP-1 (=tyrosine-related protein 1), mostly in a concentration-dependent manner. Eight triterpenoids, 10-17, showed potent inhibitory effects on EBV-EA induction with the IC50 values in the range of 269-363 mol ratio/32 pmol TPA, while these compounds exhibited no DPPH scavenging activities (IC50 >100 µM). On the other hand, the nine phenolic compounds, 1-9, exhibited potent radical-scavenging activities (IC50 1.4-10.9 µM) with weak inhibitory effects on EBV-EA induction (IC50 460-518 mol ratio/32 pmol TPA). The tannin 6 and seven triterpenoids, 10-16, have been shown to inhibit TPA-induced inflammation (1 µg/ear) in mice with the ID50 values in the range of 0.06-0.33 µmol/ear. Arjungenin (10) exhibited inhibitory effect on skin-tumor promotion in an in vivo two-stage mouse-skin carcinogenesis test based on 7,12-dimethylbenz[a]anthracene (DMBA) as initiator and with TPA as promoter. Compounds 1, 2, 4, 5, 7-9, 12, and 13, against HL60 cell line, compounds 1 and 4, against AZ521 cell line, and compounds 1, 11, and 12, against SK-BR-3 cell line, showed moderate cytotoxic activities (IC50 13.9-73.2 µM).

Appraisal of biological activities and identification of phenolic compound of African marigold (Tagetes erecta) flower extract.

The flowers of African marigold (Tagetes erecta L), a medicinal plant widely cultivated in Thailand, were subjected to evaluation for total phenolics, DPPH scavenging and thiobarbituric acid-reactive substance (TBARs) assays as well as tyrosinase inhibitory activity. In preliminary studies, the ethyl acetate (EA) extract obtained by continuous extraction showed the highest activities with highest phenolic content among all extracts. Bioassay-guided fractionation of EA extract led to isolation of a flavonoid identified as quercetagetin. Interestingly, it was found that quercetagetin exhibited potent DPPH scavenging activity with IC50 of 3.70 µg/ml which is about 2-3 times higher activity than standard quercetin (IC50 5.07 µg/ml) and trolox (IC50 9.93 µg/ml). Moreover, it exhibited tyrosinase inhibitory activity on L-tyrosine (IC50 89.31 µg/ml), higher than α- and ß-arbutins (IC50 157.77 and 222.35 µg/ml) and slightly higher (IC50 128.41 µg/ml) than ellagic acid (IC50 151.1 µg/ml) when using L-DOPA as substrate. Testing with skin fibroblasts, all the extracts and quercetagetin demonstrated no toxic effect. These finding strongly indicate that African marigold flower is a promising source of natural antioxidative and tyrosinase inhibitory substances with safe to skin.

Surface-Modified Carboxylated Cellulose Nanofiber Hydrogels for Prolonged Release of Polyhexamethylene Biguanide Hydrochloride (PHMB) for Antimicrobial Applications.

The surface modification of cellulose nanofibers (CNFs) using a 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)/sodium bromide (NaBr)/sodium hypochlorite (NaClO) system was successful in improving their hydrophilicity. Following that, we fabricated hydrogels containing carboxylated cellulose nanofibers (c-CNFs) and loaded them with polyhexamethylene biguanide (PHMB) using a physical crosslinking method, aiming for efficient antimicrobial uses. The morphological and physicochemical properties of all hydrogel formulations were characterized, and the results revealed that the 7% c-CNFs-2 h loaded with PHMB formulation exhibited desirable characteristics such as regular shape, high porosity, good mechanical properties, suitable gel content, and a good maximum swelling degree. The successful integration of PHMB into the c-CNF matrix was confirmed by FTIR analysis. Furthermore, the 7% c-CNFs-2 h loaded with the PHMB formulation demonstrated PHMB contents exceeding 80% and exhibited a prolonged drug release pattern for up to 3 days. Moreover, this formulation displayed antibacterial activity against S. aureus and P. aeruginosa. In conclusion, the novel approach of c-CNF hydrogels loaded with PHMB through physical crosslinking shows promise as a potential system for prolonged drug release in topical drug delivery while also exhibiting excellent antibacterial activity.