Facile synthesis of food-grade and size-controlled nanocarriers based on self-assembly of procyanidins and phycocyanin

Characterization of emulgels formulated with phycocyanin and diutan gum as a novel approach for biocompatible delivery systems

Phycocyanin (PC), a protein derived from algae, is non-toxic and biocompatible. Due to its environmental and sustainable properties, it has been studied as an alternative stabilizer for food emulsions. In this sense, the main objective of this work is to evaluate the effectiveness of PC and its use in combination with diutan gum (DG), a biological macromolecule, to prepare emulgels formulated with avocado oil. Z-potential measurements show that the optimum pH for working with PC is 2.5. Furthermore, the system exhibited a structured interface at this pH. The surface tension did not decrease further above 1.5 wt% PC. Interestingly, emulsions formulated with >1.5 wt% PC showed recoalescence immediately after preparation. Although 1.5 wt% had the smallest droplet size, this emulsion underwent creaming due to the low viscosity of the system. DG was used in combination with PC to increase viscosity and reduce creaming. As little as 0.1 wt% DG was sufficient to form an emulgel when incorporated into the previous emulsion, which exhibited pseudoplastic behaviour and viscoelastic properties with very low creaming rates. However, the use of PC in combination with DG resulted in a non-aggregated and stable emulgel with 1.5 wt% PC and 0.1 wt% DG.

Customized development of 3D printed anthocyanin-phycocyanin polychromatic oral film via chondroitin sulfate homeostasis: A platform based on starch and κ-carrageenan

The development of oral film with diverse colors and customized nutrition is in line with the innovation of emerging food. In this study, polychromatic system was formed by regulating the ratio of phycocyanin (PC) to blueberry anthocyanin (BA). Further, chondroitin sulfate (CS) was utilized to achieve color-enhanced and homeostatic effects on PC-BA, and κ-carrageenan (KC) - starch complex was exploited as printing ink to construct oral film system. The color-enhanced effect of CS is mainly related to the complexation of sulfate groups, and the film-forming substrates are combined mainly through hydrogen bonding. In addition, the proportion of KC modulated the gel structure of printing ink, and affected 3D printability and physical properties of oral film. OF II (1.5 % KC content) had a uniform and dense network structure, with the most stable color and the highest BA retention (70.33 %) after 8 d of light exposure. Importantly, OF II had an excellent slow-release effect, and BA release rate was as high as 92.52 %. The optimized components can form polychromatic oral film with controllable color and structure, and provide new insights for the creation of sensory personalized and nutritionally customized food.

Design and preparation of novel antioxidant and antibacterial films containing procyanidins and phycocyanin for food packaging

The purpose of this study was to design a novel antioxidant and antibacterial film for food packaging using food-grade raw materials. The films were designed and fabricated based on carboxymethyl chitosan and pectin incorporated with procyanidins (PCs) and phycocyanin (Phy) by the tape casting method. The effects of different proportions of PCs and Phy on the properties and functions of the prepared films were studied. The results showed that the thickness of films could range from 55 to 70 μm, with dense network structure and uniform distribution of elements. Compared with C-Film group, the film loaded with PCs and Phy had lower water solubility and swelling rate, and higher tensile strength and elongation at break. FITR and XRD spectra revealed the molecular interaction mechanism among carboxymethyl chitosan, pectin, PCs and Phy, which could effectively endow the films with ultraviolet barrier properties. Moreover, the addition of PCs and Phy could effectively improve the antioxidant capacity and antibacterial effect of films, for example, the free radical scavenging abilities of most films were above 80% when the concentration of PCs was 40 μg mL-1. In view of these functional properties, the prepared film containing PCs and Phy have been successfully used in food packaging, which was proved by the preservation experiment of grapes. This study can provide theoretical and technical guidance for the preparation of biodegradable antibacterial films, and their application in the food packaging field.

Doxorubicin-Loaded Microalgal Delivery System for Combined Chemotherapy and Enhanced Photodynamic Therapy of Osteosarcoma

Osteosarcoma (OS) is considered the most frequent type of primary malignant bone tumor. Currently, radiotherapy, photodynamic (PDT), and other therapies for osteosarcoma are limited by tumor hypoxia and single efficacy and serve side-effects. Herein, we reported a microalgal drug delivery system (SpiD), doxorubicin (DOX)-loaded Spirulina platensis (Spi) for OS therapy. The specific surface of Spirulina platensis allowed for effective loading of DOX via surface channels and electrostatic interactions. Under 650 nm laser irradiation, SpiD enabled high oxygen production by photosynthesis and enhanced reactive oxygen species (ROS) generation via chlorophyll-assisted photosensitization, synergistically killing tumor cells with the released DOX. Combined chemotherapy and enhanced PDT mediated by SpiD exerted synergic antitumor effects and resulted in potent therapeutic efficacy in orthotopic osteosarcoma mice. Furthermore, SpiD could reduce the side-effects of chemotherapy, showing excellent blood and tissue safety. Taken together, this microalgal drug delivery system provided a natural, efficient, safe, and inexpensive strategy for OS treatment.

Size-controllable food-grade nanoparticles based on sea cucumber polypeptide with good anti-oxidative capacity to prolong lifespan in tumor-bearing mice

Liver cancer, a malignancy with a rising global incidence, poses a significant challenge in achieving effective treatment outcomes. As food-derived nutrient, sea cucumber peptide (SCP) has shown promising anticancer effects. Therefore, we explored the nanodelivery systems to encapsulate SCP to enhance its stability in the gastrointestinal tract and improve absorption within the tumor microenvironment. This study aimed to develop size-controllable multifunctional nanoparticles using SCP, procyanidins (PCs), and vanillin through molecular assembly via a one-pot Mannich condensation approach. These food-grade nanoparticles demonstrated water solubility and exhibited a spherical structure with sizes ranging from 441 to 1360 nm, depending on the concentration of the reactants. In vitro cell experiments demonstrated that SCP nanoparticles modified with PCs effectively reduced the generation of reactive oxygen species from H2O2 and acrylamide while maintaining normal levels of mitochondrial membrane potential. Furthermore, in vivo nutrition intervention studies conducted on tumor-bearing mice revealed that mice treated with SCP nanoparticles exhibited a survival rate of 40 %, which was significantly higher than the 0 % and 20 % survival rates observed in the control and SCP-treated groups, respectively. These findings suggest that SCP nanoparticles, possessing antioxidative properties and controllable sizes, hold potential for precision nutrition in the field of cancer treatment.

Construction of Phlorotannin-Based Nanoparticles for Alleviating Acute Liver Injury

Acute liver injury (ALI) is a severe health condition with limited treatment options. Phlorotannin (PT), a natural compound extracted from seaweeds, has shown potential in improving liver function. However, its poor stability and bioavailability have limited its applications in vivo. In this study, we developed PT-based nanoparticles (NPs) through a Mannich reaction with glycine, which exhibited good biocompatibility and prolonged circulation time in vivo. Our results revealed that the PT NPs possess strong free radical scavenging ability, effectively reducing reactive oxygen species (ROS) and alleviating oxidative stress and proinflammatory responses in the H2O2-induced oxidative damage model of HepG2 cells. Furthermore, the PT NPs effectively attenuated oxidative stress and inflammation in the liver tissue of carbon tetrachloride (CCl4)-induced liver injury mice by regulating the Nrf2/HO-1 signaling pathway. In summary, our results suggested that the PT NPs could serve as a promising nano-therapeutic strategy for alleviating ALI.

Mechanistic insights into the cinnamaldehyde modification of lignin for sustainable anti-fungal reagent

The limited anti-fungal activity of enzymatic hydrolysis lignin (EHL) has been a challenge in its direct application as a bamboo preservative. To address this issue, the cinnamaldehyde modification of EHL was carried out to introduce anti-fungal structures into the lignin matrix, effectively enhancing its anti-fungal activity. The results demonstrated that the minimal inhibitory concentrations of the modified lignin (EHL-DC) against Aspergillus niger significantly improved from 16 mg/mL to 1 mg/mL, with comparable enhancements in anti-fungal activity against other fungi. As a result of the modification, the EHL-DC is more prone to interact with fungal cell membranes, contributing to a roughened, shrunken hyphal surface and a decrease in mycelial biomass. Multiple characterization methods were employed to better grapple with the EHL-DC chemical changes. The nitrogen content increased from 2.3 % to 8.3 %, and alterations in elemental compositions further support the proposed reaction mechanism and its role in enhancing EHL's anti-fungal activity. This study offers novel insights into the high-value utilization of enzymatic hydrolysis lignin based on green chemistry principles.

Microfluidic fabrication of size-controlled nanocarriers with improved stability and biocompatibility for astaxanthin delivery

Improving the stability of astaxanthin (AST) is a vital way to enhance its oral bioavailability. In this study, a microfluidic strategy for the preparation of astaxanthin nano-encapsulation system was proposed. Thanks to the precise control of microfluidic and the rapid preparation ability of the Mannich reaction, the resulting astaxanthin nano-encapsulation system (AST-ACNs-NPs) was obtained with average sizes of 200 nm, uniform spherical shape and high encapsulation rate of 75%. AST was successfully doped into the nanocarriers, according to the findings of the DFT calculation, fluorescence spectrum, Fourier transform spectroscopy, and UV-vis absorption spectroscopy. Compared with free AST, AST-ACNs-NPs showed better stability under the conditions of high temperature, pH and UV light with<20% activity loss rate. The nano-encapsulation system containing AST could significantly reduce the hydrogen peroxide produced by reactive oxygen species, keep the potential of the mitochondrial membrane at a healthy level, and improve the antioxidant ability of H₂O₂-induced RAW 264.7 cells. These results indicated that microfluidics-based astaxanthin delivery system is an effective solution to improve the bioaccessibility of bioactive substances and has potential application value in food industry.

Coassembly of Fiber Hydrogel with Antibacterial Activity for Wound Healing

Wound healing remains a critical challenge due to its vulnerability to bacterial infection and the complicated inflammatory microenvironment. Herein, we report a novel antibacterial hydrogel constructed only by gallic acid (GA) and phycocyanin (PC), which is expected for the treatment of bacteria-infected wounds. These GA/PC hydrogels (GP) was found to coassemble into fibrous networks with a diameter of around 2 μm mainly through noncovalent interactions of hydrogen bonds, van der Waals force, and π interaction. Notably, these GP hydrogels showed excellent rheological properties (i.e., storage modulus of more than 9.0 × 10⁴ Pa) and outstanding biocompatibility and antibacterial activities. Thanks to the incorporation of GA and PC, the GP hydrogels enabled adherence to the moist wound tissue and achieved a sustained release of GA and PC into the wound skin, therefore effectively attenuating inflammation and accelerating wound healing both in normal mice and bacteria-infected mice through regulating the expression of the tight junction protein and the alleviation of oxidative stress. Considering these results, these GP hydrogels are demonstrated to be a promising candidate for bacteria-infected wound healing.