There exists a technological need for advanced materials with improved properties for emerging biomedical applications. Recent developments in macroporous materials have demonstrated their applicability as indispensable tools in biomedical research. Cryogels, which are materials with a macroporous 3D structure, are produced as a result of controlled freezing during polymerization with a highly interconnected polymer network. Cryogels’ interest lies in their ability to address some of the limitations of their hydrogel analogues. In this review, hydrogel and cryogel basic concepts are discussed as a short primer for readers unfamiliar with the cryogels literature. Next, a general overview of the methods for synthesis and characterization of cryogels is provided, highlighting key concepts relevant to cryogels and explaining their unique properties. Finally an in‐depth overview of specific technologies and fields where cryogels have been applied is given. It is argued that the latest advances in cryogel technologies are able to address challenges in bioseparation, tissue engineering, and other emerging bioengineering disciplines.

Sophorolipids (SLs), biosurfactants with antimicrobial properties, have been tried to address the problem of antibiotic resistance. The synergistic action of SL and antibiotics was checked using standard microdilution and spread plate methods. WithStaphylococcus aureus, SL-tetracycline combination achieved total inhibition before 4 h of exposure while tetracycline alone couldnot achieve total inhibition till the end of 6 h. The inhibition caused by exposure of bacterium to SL-tetracycline mixture was~25% more as compared to SL alone. In spite of known robustness of gram-negative bacteria, SL-cefaclor mixture proved to be efficient againstEscherichia coliwhich showed~48% more inhibition within 2 h of exposure as compared to cefaclor alone. Scanning electron microscopy of the cells treated with mixture revealed bacterial cell membrane damage and pore formation. Moreover, SLs being a type of asymmetric bola, they are expected to form self-assemblies with unique functionality. This led to the speculation that SLs being amphiphilic in nature can span through the structurally alike cell membrane and facilitate the entry of drug molecules.

Lack of suitable auto/allografts has been delaying surgical interventions for the treatment of numerous disorders and has also caused a serious threat to public health. Tissue engineering could be one of the best alternatives to solve this issue. However, deficiency of oxygen supply in the wounded and implanted engineered tissues, caused by circulatory problems and insufficient angiogenesis, has been a rate-limiting step in translation of tissue-engineered grafts. To address this issue, we designed oxygen-releasing electrospun composite scaffolds, based on a previously developed hybrid polymeric matrix composed of poly(glycerol sebacate) (PGS) and poly(ε-caprolactone) (PCL). By performing ball-milling, we were able to embed a large percent of calcium peroxide (CP) nanoparticles into the PGS/PCL nanofibers able to generate oxygen. The composite scaffold exhibited a smooth fiber structure, while providing sustainable oxygen release for several days to a week, and significantly improved cell metabolic activity due to alleviation of hypoxic environment around primary bone-marrow-derived mesenchymal stem cells (BM-MSCs). Moreover, the composite scaffolds also showed good antibacterial performance. In conjunction to other improved features, such as degradation behavior, the developed scaffolds are promising biomaterials for various tissue-engineering and wound-healing applications.

Traumatic joint injuries can result in significant cartilage defects, which can greatly increase the risk of osteoarthritis development. Due to the limited self-healing capacity of avascular cartilage, tissue engineering approaches are required for filling defects and promoting cartilage regeneration. Current approaches utilize invasive surgical procedures for extraction and implantation of autologous chondrocytes, therefore injectable biomaterials have gained interest in order to minimize the risk of infection as well as patient pain and discomfort. Here, we engineered biomimetic, hyaluronic acid (HA)-based cryogel scaffolds that possess shape-memory properties as they contract and regain their shape following syringe injection to non-invasively fill cartilage defects. The cryogels, fabricated with HA and glycidyl methacrylate at -20 °C, resulted in an elastic, macroporous and highly interconnected network that provided a conducive microenvironment for chondrocytes to remain viable and metabolically active following injection through a syringe needle. Chondrocytes seeded within cryogels and cultured for 15 days exhibited enhanced cell proliferation, metabolism and production of cartilage extracellular matrix glycosaminoglycans compared to in HA-based hydrogels. Furthermore, immunohistochemical staining revealed production of collagen type II from chondrocyte-seeded cryogels, indicating the maintenance of cell phenotype. These results demonstrate the potential of chondrocyte-seeded, HA-based, injectable cryogel scaffolds to promote regeneration of cartilage tissue for non-surgically invasive defect repair.

Sophorolipids (SLs) are glycolipidic biosurfactants suitable for various biological and physicochemical applications. The nonedible Jatropha oil has been checked as the alternative raw material for SL synthesis usingC. bombicola(ATCC22214). This is useful towards lowering the SL production cost. Through optimization of fermentation parameters and use of resting cell method, the yield 15.25 g/L could be achieved for Jatropha oil derived SL (SLJO) with 1% v/v oil feeding. The synthesized SL displayed good surfactant property. It reduced the surface tension of distilled water from 70.7 mN/m to 33.5 mN/m with the Critical Micelle Concentration (CMC) value of 9.5 mg/L. Keeping the prospective use of the SL in mind, the physicochemical properties were checked along with emulsion stability under temperature, pH stress, and in hard water. Also antibacterial action and stain removal capability in comparison with commercial detergent was demonstrated. SLJO enhanced the detergent performance. Based on the results, it can be said that SLs have utility as fabric cleaner with advantageous properties such as skin friendly nature, antibacterial action, and biodegradability. Therefore SLs are potential green molecules to replace synthetic surfactants in detergents so as to reduce harm caused to environment through detergent usage.