Bifidobacteria Encapsulation and Viability of Probiotic Culture during Oral Delivery in a Milk Drink Matrix

The use of an alginate hydrogel exclusively for the immobilization of bifidobacteria during oral delivery led to a decrease in the total number of bifidobacteria to 4.0 lg CFU/ml in pH gradients in models of the stomach and intestines, which required clarification of the composition of the protective coating. The introduction of resistant starch into the composition of the microcapsule contributed to the preservation of the viability of immobilized bifidobacteria up to 87% of the initial concentration when passing through the model environment simulating the human digestion system. The introduction of sodium carboxymethylcellulose into the composition of the hydrogel contributed to the regulation of the degradation of the polymer matrix and the controlled release of bifidobacteria. The use of sodium carboxymethylcellulose 0.5% in the formation of a polymer microcapsule provided the maximum encapsulation efficiency of 93.2% and the maximum decay rate of bacteria-loaded microcapsules of 95.7%. The modified alginate matrix contributes to maintaining the level of viable cells of probiotic microorganisms (Bifidobacterium bifidum 791) of at least 108 CFU/g when stored for three weeks. As a result of the research, a system for oral delivery of immobilized bifidobacteria in the structure of microparticles with a closed surface in the matrix of a milk drink has been developed, which increases the effectiveness of probiotics for human health in the composition of food products.

Multifunctional smart hydrogels: potential in tissue engineering and cancer therapy

In recent years, clinical applications have been proposed for various hydrogel products. Hydrogels can be derived from animal tissues, plant extracts and/or adipose tissue extracellular matrices; each type of hydrogel presents significantly different functional properties and may be used for many different applications, including medical therapies, environmental pollution treatments, and industrial materials. Due to complicated preparation techniques and the complexities associated with the selection of suitable materials, the applications of many host-guest supramolecular polymeric hydrogels are limited. Thus, improvements in the design and construction of smart materials are highly desirable in order to increase the lifetimes of functional materials. Here, we summarize different functional hydrogels and their varied preparation methods and source materials. The multifunctional properties of hydrogels, particularly their unique ability to adapt to certain environmental stimuli, are chiefly based on the incorporation of smart materials. Smart materials may be temperature sensitive, pH sensitive, pH/temperature dual sensitive, photoresponsive or salt responsive and may be used for hydrogel wound repair, hydrogel bone repair, hydrogel drug delivery, cancer therapy, and so on. This review focuses on the recent development of smart hydrogels for tissue engineering applications and describes some of the latest advances in using smart materials to create hydrogels for cancer therapy.

Injectable biopolymer based hydrogels for drug delivery applications

Biopolymer based pH-sensitive hydrogels were prepared using chitosan (CS) with polyethylene glycol (PEG) of different molecular weights in the presence of silane crosslinker. The incorporated components remain undissolved in different swelling media as they are connected by siloxane linkage which was confirmed by Fourier transform infrared spectroscopy. The swelling in water was enhanced by the addition of higher molecular weight PEG. The swelling behaviour of the hydrogels against pH showed high swelling in acidic and basic pH, whereas, low swelling was examined at pH 6 and 7. This characteristic pH responsive behaviour at neutral pH made them suitable for injectable controlled drug delivery. The controlled release analysis of Cefixime (CFX) (model drug) loaded CS/PEG hydrogel exhibited that the entire drug was released in 30 min in simulated gastric fluid (SGF) while in simulated intestinal fluid (SIF), 85% of drug was released in controlled manner within 80 min. This inferred that the developed hydrogels can be an attractive biomaterial for injectable drug delivery with physiological pH and other biomedical applications.

The effect of polymer and CaCl2 concentrations on the sulfasalazine release from alginate-N,O-carboxymethyl chitosan beads

In this study, pH-sensitive blended polymeric beads were prepared by ionic gelation of mixed alginate and N,O-carboxymethyl chitosan (NOCC) solutions in aqueous media containing calcium chloride. To prepare drug-loaded beads, sulfasalazine (SA) as a model drug was added to the initial aqueous polymer solution. These beads were characterized and evaluated in vitro as potential carriers for colon-specific drug delivery. A 3² full factorial experimental design was employed to evaluate the effect of polymer and CaCl₂ concentrations on swelling and drug release behavior of the beads in simulated gastrointestinal tract fluid. It was found that the rate of swelling and drug release decreased significantly with increasing polymer and CaCl₂ concentrations, but polymer concentration was more effective than CaCl₂ concentration. The beads prepared using 4.5% polymer concentration and 4% CaCl₂ concentration retained approximately 60% of the loaded drug before approaching the simulated colonic fluid. Based on the results, the alginate-NOCC beads prepared with high polymer concentration could be potentially suitable polymeric carriers for colon-specific delivery of SA.