Physicochemical, Structural, and In Vitro Gastrointestinal Tract Release Properties of Sodium Alginate-Based Cryogel Beads Filled with Hydroxypropyl Distarch Phosphate as a Curcumin Delivery System.

The objectives of this study were to produce sodium alginate (SA)-based cryogel beads filled with different concentrations (0, 0.4, 1.0, and 2.5%, w/w) of hydroxypropyl distarch phosphate (HDP) as a curcumin delivery system and to investigate the physicochemical, structural, and in vitro gastrointestinal tract release properties of the cryogel beads. According to FT-IR analysis, the formation of ionic crosslinking between SA and Ca2+ and the presence of HDP were found. XRD analysis demonstrated the successful encapsulation of curcumin in the beads by observing the disappearance of the characteristic peaks of curcumin. SEM analysis results revelated that SA-based cryogel beads exhibited a denser internal structure as the HDP concentration was increased. The encapsulation efficiency of curcumin in SA cryogel beads filled with HDP concentration from 0% to 2.5% was increased from 31.95% to 76.66%, respectively, indicating that HDP can be a suitable filler for the encapsulation of curcumin in the production of SA-based cryogel beads. After exposure to simulated gastric fluid (SGF) and simulated intestinal fluid (SIF), the release rate of curcumin was decreased as HDP concentration was increased. Accordingly, SA-based cryogel beads filled with HDP can be utilized for the delivery system of curcumin in the food industry.

Combined protein A imprinting and cryogelation for production of spherical affinity material.

Cryogels have been demonstrated to be efficient when applied for protein isolation. Owing to their macroporous structure, cryogels can also be used for treating particle-containing material, e.g. cell homogenates. Another challenging development in protein purification technology is the use of molecularly imprinted polymers (MIPs). These MIPs are robust and can be used repeatedly. The paper presents a new technology that combine the formation of cryogel beads concomitantly with making imprints of a protein. Protein A was chosen as the print molecule which was also be the target in the purification step. The present paper describes a new method to produce protein-imprinted cryogel beads. The protein-imprinted material was characterized and the separation properties were evaluated with regard to both the target protein and whole cells with target protein exposed on the cell surface. The maximum protein A adsorption was 18.1 mg/g of wet cryogel beads. The selectivity coefficient of protein A-imprinted cryogel beads for protein A was 5.44 and 12.56 times greater than for the Fc fragment of IgG and protein G, respectively.

Molecularly imprinted cryogel beads for cholesterol removal from milk samples.

This study presents the development of a cholesterol-selective adsorbent that can be easily produced for the highly efficient removal of cholesterol from milk. A fundamental affinity separation technology which was combined with the specific recognition property of molecular imprinting with a high flow rate and the resulting cryogel was used to separate cholesterol separation from milk samples. The proposed material offers a reasonable pore size and structure, high surface area, and mechanical and chemical stability. To separation the cholesterol from milk, poly(2-hyroxyethyl methacrylate-N-methacryloyl-l-tryptophan methylester) cryogel beads were prepared using a functional monomer that allowed the formation of cholesterol-selective binding sites and enhanced the selective removal of cholesterol from milk. Characterization studies of the cholesterol-imprinted cryogel beads (CHO-MIPs) were carried out by attenuated total reflectance-Fourier transform infrared spectroscopy, scanning electron microscopy, elemental analysis, water-uptake tests and surface area measurements. The interactions between CHO-MIP and cholesterol were investigated and the factors affecting the adsorption of cholesterol were determined to find optimum conditions. Reusability as a measure of the continuity of the prepared CHO-MIPs was also investigated. The selectivity of the CHO-MIP beads was determined by using competing molecules (estradiol and progesterone), which are cholesterol analogues. The experimental data showed that the specific areas of the CHO-MIP and non-imprinted (NIP) cryogel beads were 17.6 and 14.7 m2/g, respectively. The CHO-MIP cryogel beads were 4.77 and 2.76 fold more selective for cholesterol compared to estradiol and progesterone respectively. The cholesterol adsorption capacity of the CHO-MIP beads was 288.72 mg/g when the cholesterol concentration in solution was 3.0 mg/mL. After eight adsorption-desorption cycles, the adsorption capacity of the CHO-MIP beads decreased by 9.21 %. The Langmuir-Freundlich isotherm model was well fitted as compare to Langmuir and Freundlich isotherms. The obtained kinetics data showed that a pseudo-second order mechanism was predominant for the CHO-MIP cryogel bead adsorption.

Carboxylated cellulose cryogel beads via a one-step ester crosslinking of maleic anhydride for copper ions removal.

In this study, we developed a one step protocol to prepare highly carboxylated and chemically crosslinked cellulose nanofibril (CNF) cryogel beads using maleic anhydride (MA). Fourier transform infrared spectroscopy (FTIR) and conductometric-potentiometric titration results confirmed the presence of carboxyl groups and ester linkages produced simultaneously during the ring open reaction of MA, yielding a carboxylic content of up to 2.78 mmol/g. The effect of CNF concentration on the morphology and wet mechanical strength of the crosslinked cryogel beads were also investigated, and results suggested that higher CNF concentration yielded a compact network that displayed a maximum compressive stress of 2800 Pa at 60 % strain. In addition, the heavy metal ions (i.e., Cu (II)) removal capacity, kinetics, mechanism as well as the recyclability of the resulted CNF-MA cryogel beads were examined.