Core-shell structured poly(vinyl alcohol)/sodium alginate bead for single-stage autotrophic nitrogen removal

2017 ◽  
Vol 322 ◽  
pp. 408-416 ◽  
Author(s):  
Hyokwan Bae ◽  
Minkyu Choi ◽  
Yun-Chul Chung ◽  
Seockheon Lee ◽  
Young Je Yoo
Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2381
Author(s):  
Katarzyna Bialik-Wąs ◽  
Ewelina Królicka ◽  
Dagmara Malina

Here, we report on studies on the influence of different crosslinking methods (ionic and chemical) on the physicochemical (swelling ability and degradation in simulated body fluids), structural (FT-IR spectra analysis) and morphological (SEM analysis) properties of SA/PVA hydrogels containing active substances of natural origin. First, an aqueous extract of Echinacea purpurea was prepared using a Soxhlet apparatus. Next, a series of modified SA/PVA-based hydrogels were obtained through the chemical crosslinking method using poly(ethylene glycol) diacrylate (PEGDA, Mn = 700 g/mol) as a crosslinking agent and, additionally, the ionic reaction in the presence of a 5% w/v calcium chloride solution. The compositions of SA/PVA/E. purpurea-based hydrogels contained a polymer of natural origin—sodium alginate (SA, 1.5% solution)—and a synthetic polymer—poly(vinyl alcohol) (PVA, Mn = 72,000 g/mol, 10% solution)—in the ratio 2:1, and different amounts of the aqueous extract of E. purpurea—5, 10, 15 or 20% (v/v). Additionally, the release behavior of echinacoside from the polymeric matrix was evaluated in phosphate-buffered saline (PBS) at 37 °C. The results indicate that the type of the crosslinking method has a direct impact on the release profile. Consequently, it is possible to design a system that delivers an active substance in a way that depends on the application.


2009 ◽  
Vol 21 (8) ◽  
pp. 758-764 ◽  
Author(s):  
Suraj Kumar Tripathy ◽  
Jin-Nyoung Jo ◽  
Kwang-Joong O ◽  
Sang-Do Han ◽  
In-Hwan Lee ◽  
...  

2021 ◽  
Author(s):  
Nantaprapa Tuancharoensri ◽  
Gareth Ross ◽  
Winita Punyodom ◽  
Sararat Mahasaranon ◽  
Jirapas Jongjitwimol ◽  
...  

2021 ◽  
Vol 398 (1) ◽  
pp. 2000194
Author(s):  
Vítor Corrêa da Costa ◽  
Fernando Gomes de Souza Junior ◽  
Luana de Castro Sousa ◽  
Kaushik Pal ◽  
Romildo Dias Tolêdo Filho

2020 ◽  
Vol 202 ◽  
pp. 110935 ◽  
Author(s):  
Shiying Wang ◽  
Qianli Ma ◽  
Ruifei Wang ◽  
Qizhan Zhu ◽  
Liupeng Yang ◽  
...  

Pharmaceutics ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 1149
Author(s):  
Ludovico Esposito ◽  
Ana Isabel Barbosa ◽  
Tânia Moniz ◽  
Sofia Costa Lima ◽  
Paulo Costa ◽  
...  

Nature has led to the discovery of biopolymers with noteworthy pharmaceutical applications. Blended biopolymers have demonstrated promising characteristics when compared with their individual counterparts. Sodium alginate (SA) is a marine polymer that has demonstrated the ability to form hydrogels, an interesting property for the development of cutaneous formulations. Predicting the good performance of blended biopolymers, a novel series of hybrid hydrogels based on SA and poly(vinyl) alcohol (PVA) were prepared. Quercetin, a natural polyphenolic flavonoid commonly found in fruits and vegetables, is widely known for its strong anti-inflammatory and antioxidant activity, thus with potential applications against melanoma, dermatitis, psoriasis, and skin ageing. Here, hydrogels were produced at different ratios of SA and PVA. The surface morphology, structure, interaction of polymers, the capacity to absorb water and the entrapment efficiency of quercetin were evaluated for the blended hydrogels. Targeting the cutaneous application of the formulations, the rheological properties of all unloaded and quercetin-loaded hydrogels revealed pseudoplastic behavior, evidence of non-thixotropy, good resistance to deformation, and profile maintenance with temperatures ranging from 20 °C up to 40 °C. The incorporation of quercetin in the hydrogel retained its antioxidant activity, confirmed by radical scavenging assays (ABTS and DPPH). The permeability of quercetin through the skin showed different penetration/permeation profiles according to the hydrogel’s blend. This behavior will allow the selection of SA-PVA at 2/1 ratio for a local and prolonged skin effect, making the use of these hydrogels a good solution to consider for the treatment of skin ageing and inflammation.


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