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Effect of operational factors on bioregeneration of binary phenol and 4-chlorophenol-loaded granular activated carbon using PVA-immobilized biomass cryogels

Leong KY, Adnan R, Lim PE, Ng SL, Seng CE

Environ Sci Pollut Res Int, 2017 Sep;24(26):20959-20971.
PMID: 28726220 DOI: 10.1007/s11356-017-9636-7

The effects of dry biomass density in cryogel beads, shaking speed and initial concentration ratio of phenol to 4-chlorophenol (4-CP) on the bioregeneration efficiencies of binary phenol and 4-CP-loaded granular activated carbon (GAC) for phenol and 4-CP, respectively, were investigated under the simultaneous adsorption and biodegradation approach. The results revealed higher bioregeneration efficiencies of binary-loaded GAC for phenol and 4-CP at higher dry biomass density but moderate shaking speed. The optimum dry biomass density in cryogel beads and shaking speed for use in bioregeneration were found to be 0.01 g/mL and 250 rpm, respectively. With respect to the initial phenol to 4-CP concentration ratio, the bioregeneration efficiencies were lower under increasing phenol and 4-CP initial concentrations, respectively, with the effect being more conspicuous under increasing 4-CP concentration. Higher bioregeneration efficiencies were achieved with the use of immobilized rather than suspended biomasses.

Matched MeSH terms: Cryogels*
Adhesive cryogel particles for bridging confined and irregular tissue defects

Xue YT, Chen MY, Cao JS, Wang L, Hu JH, Li SY, et al.

Mil Med Res, 2023 Mar 23;10(1):15.
PMID: 36949519 DOI: 10.1186/s40779-023-00451-1

BACKGROUND: Reconstruction of damaged tissues requires both surface hemostasis and tissue bridging. Tissues with damage resulting from physical trauma or surgical treatments may have arbitrary surface topographies, making tissue bridging challenging.
METHODS: This study proposes a tissue adhesive in the form of adhesive cryogel particles (ACPs) made from chitosan, acrylic acid, 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS). The adhesion performance was examined by the 180-degree peel test to a collection of tissues including porcine heart, intestine, liver, muscle, and stomach. Cytotoxicity of ACPs was evaluated by cell proliferation of human normal liver cells (LO2) and human intestinal epithelial cells (Caco-2). The degree of inflammation and biodegradability were examined in dorsal subcutaneous rat models. The ability of ACPs to bridge irregular tissue defects was assessed using porcine heart, liver, and kidney as the ex vivo models. Furthermore, a model of repairing liver rupture in rats and an intestinal anastomosis in rabbits were established to verify the effectiveness, biocompatibility, and applicability in clinical surgery.
RESULTS: ACPs are applicable to confined and irregular tissue defects, such as deep herringbone grooves in the parenchyma organs and annular sections in the cavernous organs. ACPs formed tough adhesion between tissues [(670.9 ± 50.1) J/m2 for the heart, (607.6 ± 30.0) J/m2 for the intestine, (473.7 ± 37.0) J/m2 for the liver, (186.1 ± 13.3) J/m2 for muscle, and (579.3 ± 32.3) J/m2 for the stomach]. ACPs showed considerable cytocompatibility in vitro study, with a high level of cell viability for 3 d [(98.8 ± 1.2) % for LO2 and (98.3 ± 1.6) % for Caco-2]. It has comparable inflammation repair in a ruptured rat liver (P = 0.58 compared with suture closure), the same with intestinal anastomosis in rabbits (P = 0.40 compared with suture anastomosis). Additionally, ACPs-based intestinal anastomosis (less than 30 s) was remarkably faster than the conventional suturing process (more than 10 min). When ACPs degrade after surgery, the tissues heal across the adhesion interface.
CONCLUSIONS: ACPs are promising as the adhesive for clinical operations and battlefield rescue, with the capability to bridge irregular tissue defects rapidly.

Matched MeSH terms: Cryogels
Synthesis and characterization of carbon cryogel microspheres from lignin-furfural mixtures for biodiesel production

Zainol MM, Amin NA, Asmadi M

Bioresour Technol, 2015 Aug;190:44-50.
PMID: 25919936 DOI: 10.1016/j.biortech.2015.04.067

The aim of this work was to study the potential of biofuel and biomass processing industry side-products as acid catalyst. The synthesis of carbon cryogel from lignin-furfural mixture, prepared via sol-gel polycondensation at 90°C for 0.5h, has been investigated for biodiesel production. The effect of lignin to furfural (L/F) ratios, lignin to water (L/W) ratios and acid concentration on carbon cryogel synthesis was studied. The carbon cryogels were characterized and tested for oleic acid conversion. The thermally stable amorphous spherical carbon cryogel has a large total surface area with high acidity. Experimental results revealed the optimum FAME yield and oleic acid conversion of 91.3wt.% and 98.1wt.%, respectively were attained at 65°C for 5h with 5wt.% catalyst loading and 20:1 methanol to oleic acid molar ratio. Therefore, carbon cryogel is highly potential for heterogeneous esterification of free fatty acid to biodiesel.

Matched MeSH terms: Cryogels/chemical synthesis*
Interconnected macropores cryogel with nano-thin crosslinked network regenerated cellulose

Salleh KM, Zakaria S, Gan S, Baharin KW, Ibrahim NA, Zamzamin R

Int J Biol Macromol, 2020 Apr 01;148:11-19.
PMID: 31893531 DOI: 10.1016/j.ijbiomac.2019.12.240

Dissolved oil palm empty fruit bunch cellulose (EFBC) and sodium carboxymethylcellulose (NaCMC) were chemically crosslinked with epichlorohydrin (ECH) to generate designated hydrogel. After swelling process in distilled water, the swollen hydrogel was frozen and freeze-dried to form cryogel. The swelling phenomenon of hydrogel during the absorption process gave substantial effects on thinning of crosslinked network wall, pore size and volume, steadiness of cryogel skeletal structure, and re-swelling of cryogel. The swelling effects on hydrogel were confirmed via microscopic study using variable pressure scanning electron microscope (VPSEM). From the retrieved VPSEM images, nano-thin crosslinked network wall of 24.31 ± 1.97 nm and interconnected pores were observed. As a result, the amount of water, the swelling degree, and the freeze-drying process indirectly affected the VPSEM images that indicated pore size and volume, formation of interconnected pores, and re-swelling of cryogel. This study determined the intertwined factors that affected both hydrogel and cryogel properties by investigating the swelling phenomenon and its ensuing effects.

Matched MeSH terms: Cryogels/chemistry*
Fulltext Hyaluronic Acid-Mediated Drug Delivery System Targeting for Inflammatory Skin Diseases: A Mini Review

How KN, Yap WH, Lim CLH, Goh BH, Lai ZW

Front Pharmacol, 2020;11:1105.
PMID: 32848737 DOI: 10.3389/fphar.2020.01105

Hyaluronic acid (HA), a major component of extracellular matrix has been widely applied in pharmaceutical and cosmetic industries due to its reported pharmacological properties. Various types of HA drug delivery system including nanoparticles, cryogel-based formulations, microneedle patches, and nano-emulsions were developed. There are studies reporting that several HA-based transdermal delivery systems exhibit excellent biocompatibility, enhanced permeability and efficient localized release of anti-psoriasis drugs and have shown to inhibit psoriasis-associated skin inflammation. Similarly HA is found in abundant at epidermis of atopic dermatitis (AD) suggesting its role in atopic AD pathology. Anti-allergenic effect of atopic eczema can be achieved through the inhibition of CD44 and protein kinase C alpha (PKCα) interaction by HA. Herein, we aim to evaluate the current innovation on HA drug delivery system and the other potential applications of HA in inflammatory skin diseases, focusing on atopic dermatitis and psoriasis. HA is typically integrated into different delivery systems including nanoparticles, liposomes, ethosomes and microneedle patches in supporting drug penetration through the stratum corneum layer of the skin. For instance, ethosomes and microneedle delivery system such as curcumin-loaded HA-modified ethosomes were developed to enhance skin retention and delivery of curcumin to CD44-expressing psoriatic cells whereas methotrexate-loaded HA-based microneedle was shown to enhance skin penetration of methotrexate to alleviate psoriasis-like skin inflammation. HA-based nanoparticles and pluronic F-127 based dual responsive (pH/temperature) hydrogels had been described to enhance drug permeation through and into the intact skin for AD treatment.

Matched MeSH terms: Cryogels