Eco-benign synthesis of nano­gold chitosan-bacterial cellulose in spent ground coffee kombucha consortium: Characterization, microbiome community, and biological performance.

Biomaterials that are mediocre for cell adhesion have been a concern for medical purposes. In this study, we fabricated nano­gold chitosan-bacterial cellulose (CBC-Au) via a facile in-situ method using spent ground coffee (SGC) in a kombucha consortium. The eco-benign synthesis of monodispersed gold nanoparticles (Au NPs) in modified bacterial cellulose (BC) was successfully achieved in the presence of chitosan (CHI) and a symbiotic culture of bacteria and yeast (SCOBY). The dominant microbiome community in SGC kombucha were Lactobacillaceae and Saccharomycetes. Chitosan-bacterial cellulose (CBC) and CBC-Au affected the microfibril networks in the nano cellulose structures and decreased the porosity. The modified BC maintained its crystallinity up to 80 % after incorporating CHI and Au NPs. Depth profiling using X-ray photoelectron spectroscopy (XPS) indicated that the Au NPs were distributed in the deeper layers of the scaffolds and a limited amount on the surface of the scaffold. Aspergillus niger fungal strains validated the biodegradability of each scaffold as a decomposer. Bacteriostatically CBC-Au showed better antimicrobial activity than BC, in line with the adhesion of NIH-3T3 fibroblast cells and red blood cells (RBCs), which displayed good biocompatibility performance, indicating its potential use as a medical scaffold.

Fabrication and characterization of hybrid eco-friendly high methoxyl pectin/gelatin/TiO2/curcumin (PGTC) nanocomposite biofilms for salmon fillet packaging.

Hybrid eco-friendly nanocomposite films were fabricated by blending high-methoxyl pectin, gelatin, TiO2, and curcumin through the solution casting method. Various concentrations (0-5 wt%) of TiO2 nanoparticles (TNPs) and curcumin as an organic filler were added to the blend solutions. A high TNP concentration affected the surface morphology, roughness, and compactness of the films. Additionally, 3D mapping revealed the nanoparticle distribution in the film layers. Moisture content, water solubility, and light transmittance reduced dramatically with increasing TNP content, in accordance with the water vapor and oxygen permeabilities. X-ray diffraction revealed that the films were semicrystalline nanocomposites, and the thermal properties of the films increased when 5 wt% of TNPs was incorporated into the blend solution. Fourier-transform infrared and Raman analyses revealed interactions among biopolymers, nanoparticles, and organic fillers through hydrogen bonding. The shelf life of fresh salmon fillets was prolonged to six days for all groups, revealed by total viable counts and psychrotrophic bacteria counts, and the pH of the salmon fillets could be extended until the sixth day for all groups. Biodegradation assays demonstrated a significant weight loss in the nanocomposite films. Therefore, a nanocomposite film with 5 wt% TNPs could potentially be cytotoxic to NIH 3T3 cells.

Recent developments in selenium-containing polymeric micelles: prospective stimuli, drug-release behaviors, and intrinsic anticancer activity.

Selenium is capable of forming a dynamic covalent bond with itself and other elements and can undergo metathesis and regeneration reactions under optimum conditions. Its dynamic nature endows selenium-containing polymers with striking sensitivity towards some environmental alterations. In the past decade, several selenium-containing polymers were synthesized and used for the preparation of oxidation-, reduction-, and radiation-responsive nanocarriers. Recently, thioredoxin reductase, sonication, and osmotic pressure triggered the cleavage of Se-Se bonds and swelling or disassembly of nanostructures. Moreover, some selenium-containing nanocarriers form oxidation products such as seleninic acids and acrylates with inherent anticancer activities. Thus, selenium-containing polymers hold promise for the fabrication of ultrasensitive and multifunctional nanocarriers of radiotherapeutic, chemotherapeutic, and immunotherapeutic significance. Herein, we discuss the most recent developments in selenium-containing polymeric micelles in light of their architecture, multiple stimuli-responsive properties, emerging immunomodulatory activities, and future perspectives in the delivery and controlled release of anticancer agents.

Adenine-Functionalized Supramolecular Micelles for Selective Cancer Chemotherapy.

Functional supramolecular micelles containing self-complementary multiple hydrogen bonding adenine groups (A-PPG) can spontaneously self-assemble into stable nanosized micelles in aqueous solution. These micelles can be used to selectively deliver anticancer drugs to cancer cells and effectively promote tumor cell death via apoptosis, without harming normal cells. The drug-loaded micelles exhibit tunable drug-loading capacity and rapid pH-triggered drug release under acidic conditions, as well as a high drug-entrapment stability in serum-rich media due to the reversible hydrogen-bonded adenine-adenine interactions within the micellar interior; these properties are critical to achieving effective chemotherapeutic drug delivery and controlled drug release. In vitro assays show that the drug-loaded micelles exert significant cytotoxic effects on cancer cells, with minimal effects on normal cells under physiological conditions. Cytotoxicity assays using A-PPG micelles loaded with different anticancer drugs confirm these effects. Importantly, cellular internalization and flow cytometric analyses demonstrate that the adenine moieties within A-PPG micelles significantly increase selective endocytic uptake of the supramolecular micelles by cancer cells, which in turn induce apoptotic cell death and substantially enhance the response to chemotherapy. Thus, A-PPG micelles can improve the safety and efficacy of cancer chemotherapy.

Biodegradable polymer-nanoclay composites as intestinal sleeve implants installed in digestive tract for obesity and type 2 diabetes treatment.

Obesity and type 2 diabetes have become serious health problems in 21st century. Development of non-invasive treatment to treat obesity and type-2 diabetes is still unmet needs. For targeting on this, one of the promising treatments is to implant an intestine sleeve in the gastrointestinal tract for limitation of food absorption. In this context, biodegradable polymer intestine sleeve was composed of polycaprolactone (PCL), poly-DL-lactic acid (PDLLA) and disk-shape nano-clay (Laponite®), and fabricated as an implantable device. Here, Laponite® as a rheological additive to improve the compatibility of PCL and PDLLA, and the polymers/clay composites were also evaluated by scanning electron microscopy SEM analysis and mechanical measurements. The mass ratio 90/10/1 of PCL/PDLLA/Laponite® composite was selected for fabrication of intestine sleeve, because of the highest toughness and flexibility, which are tensile strength of 91.9 N/mm2 and tensile strain of 448% at the failure point. The prepared intestine sleeve was implanted and deployed at the duodenum in type2 diabetic rats, providing significant benefits in control of the body weight and blood glucose, while compared with the non-implanted type 2 diabetic rats. More importantly, the food intake records and histopathological section reports presented that the implanted rats still have normal appetites and no noticeable acute symptoms of inflammation in the end of the test. These appreciable performances suggested the implantation of biocompatible polymer composites has a highly potential treatment for obesity and type 2 diabetes.

Fabrication of silver seeds and nanoparticle on core-shell Ag@SiO2 nanohybrids for combined photothermal therapy and bioimaging.

In this study, two core-shell nanohybrids of different morphologies, namely SiO2-coated silver (Ag) with surface-exposed silver seeds (Ag@SiO2@Agseed) and SiO2-coated Ag with surface-exposed Ag nanoparticles (Ag@SiO2@AgNPs), were fabricated using the Stober method. Potential applications in bioimaging and photothermal therapy (PTT) of the two fabricated nanohybrids were also explored. Upon exposure to visible light (400 nm), Ag@SiO2@Agseed with surface-exposed Ag seeds exhibited greater photothermal conversion efficiency than Ag@SiO2@AgNPs. In vitro MTT assays in the dark and subsequent bioimaging using HeLa cells proved the potential biocompatibility of the fabricated core-shell nanohybrids. PTT applications of the two fabricated core-shell nanohybrids were studied by incubating HeLa cells with the nanohybrids, exposure to 400 nm laser, and subsequent staining with annexin V and propidium iodide (PI), and the two core-shell nanohybrids gave distinctively different PI staining results. Interestingly, Ag@SiO2@Agseed caused higher cell death upon light exposure compared to Ag@SiO2@AgNPs as the former generated more heat within the cells. These results demonstrated potential bioimaging and PPT applications of the fabricated core-shell nanohybrids and offer a novel candidate for phototherapy-based biomedical applications.

Formation of gold decorated porphyrin nanoparticles and evaluation of their photothermal and photodynamic activity.

A core-shell gold (Au) nanoparticle with improved photosensitization have been successfully fabricated using Au nanoparticles and 5,10,15,20 tetrakis pentafluorophenyl)-21H,23H-porphine (PF6) dye, forming a dyad through molecular self-assembly. Au nanoparticles were decorated on the shell and PF6 was placed in the core of the nanoparticles. Highly stable Au nanoparticles were achieved using PF6 with poly(N-vinylcaprolactam-co-N-vinylimidazole)-g-poly(D,L-lactide) graft copolymer hybridization. This was compared with hybridization using cetyltrimethylammonium bromide and polyethylene glycol-b-poly(D,L-lactide) for shell formation with PF6-Au. The resulting PF6-poly(N-vinylcaprolactam-co-N-vinylimidazole)-g-poly(D,L-lactide)-Au core-shell nanoparticle were utilized for photothermal and photodynamic activities. The spectroscopic analysis and zeta potential values of micelles revealed the presence of a thin Au layer coated on the PF6 nanoparticle surface, which generally enhanced the thermal stability of the gold nanoparticles and the photothermal effect of the shell. The core-shell PF6-Au nanoparticles were avidly taken up by cells and demonstrated cellular phototoxicity upon irradiation with 300W halogen lamps. The structural arrangement of PF6 dyes in the core-shell particles assures the effectiveness of singlet oxygen production. The study verifies that PF6 particles when companied with Au nanoparticles as PF6-Au have possible combinational applications in photodynamic and photothermal therapies for cancer cells because of their high production of singlet oxygen and heat.