RESUMEN

Sacran is a cyanobacterial supergiant polysaccharide with carboxylate and sulfate groups that exhibits antiallergic and antiinflammatory properties. However, its high anionic functions restrict cell compatibility. Quaternary ammonium groups were substituted to form sacran ampholytes, and the cell compatibility of the cationized sacran hydrogels was evaluated. The cationization process involved the reaction of N-(3-chloro-2-hydroxypropyl)trimethylammonium chloride with the primary amine or hydroxyl groups of sacran. The degree of cationization ranged from 32 to 87% for sugar residues. Hydrogels of sacran ampholytes were prepared by annealing their dried sheets by thermal cross-linking; these hydrogels exhibited anisotropic expansion properties. The water contact angle on the hydrogels decreased from 26.5 to 15.3° with an increase in the degree of cationization, thereby enhancing hydrophilicity. The IC50 values of sacran ampholytes decreased with an increased degree of cationization, resulting in a reduction in cytotoxicity toward the L-929 mouse fibroblast cell line. This reduction was associated with an increase in the cell proliferation density after 3 days of incubation. Scanning electron microscopy images showed fibroblast intercellular connections. Therefore, the sacran ampholyte hydrogel exhibited increased hydrophilicity and cell compatibility, which is beneficial for various biomedical applications.

Asunto(s)

Cianobacterias , Hidrogeles , Polisacáridos , Hidrogeles/química , Hidrogeles/farmacología , Ratones , Animales , Polisacáridos/química , Polisacáridos/farmacología , Cianobacterias/química , Fibroblastos/efectos de los fármacos , Línea Celular , Proliferación Celular/efectos de los fármacos , Cationes/química , Compuestos de Amonio Cuaternario/química , Compuestos de Amonio Cuaternario/farmacología , Sulfatos/química , Materiales Biocompatibles/química , Materiales Biocompatibles/farmacología , Propanoles

RESUMEN

Herein, a sensitive colorimetric detection strategy is proposed for Ag+ detection based on the use of environmentally friendly synthesis of gold nanoparticles (AuNPs), at room temperature, using (tannic acid, TA), as the reductant and pullulan (PUL) as stabilizing agent. The colloidal solution (TA/PUL-AuNPs), at the optimal synthesis conditions, showed maximum absorbance at 529 nm with a berry red color. TEM and FESEM validated that the particles are spherical and monodispersed, while other characterization results elucidated the role of pullulan in the nano-synthesis. Ag+ addition to the probe (TA/PUL-AuNPs), pH 11, resulted in naked-eye color changes, owing to Au@Ag core shell nanostructure formation. Further, the added Ag+ is reduced to AgNPs, on the surface of the TA/PUL-AuNPs probe. A hypsochromic shift in the absorption maximum, from 529 to 409 nm was observed, while (AAg+-Abl)@409 nm exhibited linearity with Ag+ concentrations, from 0.100 to 150 µM. The estimated limit of detection was 30.8 nM, which is far lower than the acceptable limit of 0.930 µM from the regulatory agency. The TA/PUL-AuNPs probe was further tested for Ag+ detection in lake water samples, and it displayed satisfactory detection performances for real sample applications.

RESUMEN

The mechanical properties for paper sheets composited with glucose (Glc), methyl cellulose (MC), and carboxymethyl cellulose (CMC) were investigated. The paper composites were prepared by immersing paper sheets in aqueous solutions of these materials and drying at 100 °C for 30 min. The stress-strain curves for these paper composites were measured by a uniaxial tensile apparatus with a stretching speed of 2 mm/min. The breaking stress and strain for untreated paper were 24 MPa and 0.016, respectively. The paper composites demonstrated stress-strain curves similar to the untreated paper; however, the breaking point largely differed for these composites. The breaking strain and breaking stress for the Glc composite slightly decreased and those for the MC composite gradually increased with the concentration of materials composited. Significant increases in the mechanical properties were observed for the CMC composite. The breaking stress, breaking strain, and breaking energy for the 3 wt.% CMC composite were 2.0-, 3.9-, and 8.0-fold higher than those for untreated paper, respectively. SEM photographs indicated that the CMC penetrated into the inner part of the paper. These results strongly suggest that the mechanical improvement for CMC composites can be understood as an enhancement of the bond strength between the paper fibrils by CMC, which acts as a bonding agent. It was also revealed that the breaking strain, breaking stress, and breaking energy for the CMC composites were at maximum at the first cycle and decreased gradually as the immersion cycles increased.

RESUMEN

This study presented a green, facile and efficient approach for a new combination of targeted gold nanohybrids functionalized with folate-hydrophobic-quaternized pullulan delivering hydrophobic camptothecin (CPT-GNHs@FHQ-PUL) to enhance the efficacy, selectivity, and safety of these systems. New formulations of spherical CPT-GNHs@FHQ-PUL obtained by bio-inspired strategy were fully characterized by TEM, EDS, DLS, zeta-potential, UV-vis, XRD, and ATR-FTIR analyses, showing a homogeneous particles size with an average size of approximately 10.97 ± 2.29 nm. CPT was successfully loaded on multifunctional GNHs@FHQ-PUL via intermolecular interactions. Moreover, pH-responsive CPT release from newly formulated-CPT-GNHs@FHQ-PUL exhibited a faster release rate under acidic conditions. The intelligent CPT-GNHs@FHQ-PUL (IC50 = 6.2 µM) displayed a 2.82-time higher cytotoxicity against human lung cancer cells (Chago-k1) than CPT alone (IC50 = 2.2 µM), while simultaneously exhibiting less toxicity toward normal human lung cells (Wi-38). These systems also showed specific uptake by folate receptor-mediated endocytosis, exhibited excellent anticancer activity, induced the death of cells by increasing apoptosis pathway (13.97%), and arrested the cell cycle at the G0-G1 phase. The results of this study showed that the delivery of CPT by smart GNHs@FHQ-PUL systems proved to be a promising strategy for increasing its chemotherapeutic effects.