Bioactive glasses have long been investigated in mineralized tissue regeneration, but recently their potential applications in soft tissue repair, and in particular wound healing, have demonstrated great promise.

The efficient capture of radionuclides with long half-lives such as technetium-99 ((99)Tc), uranium-238 ((238)U), and iodine-129 ((129)I) is pivotal to prevent their transport into groundwater and/or release into the atmosphere. While different sorbents have been considered for capturing each of them, in the current work, nanostructured chalcogen-based aerogels called chalcogels are shown to be very effective at capturing ionic forms of (99)Tc and (238)U, as well as nonradioactive gaseous iodine (i.e., a surrogate for (129)I2), irrespective of the sorbent polarity. The chalcogel chemistries studied were Co0.7Bi0.3MoS4, Co0.7Cr0.3MoS4, Co0.5Ni0.5MoS4, PtGe2S5, and Sn2S3. The PtGe2S5 sorbent performed the best overall with capture efficiencies of 98.0% and 99.4% for (99)Tc and (238)U, respectively, and >99.0% for I2(g) over the duration of the experiment. The capture efficiencies for (99)Tc and (238)U varied between the different sorbents, ranging from 57.3-98.0% and 68.1-99.4%, respectively. All chalcogels showed >99.0% capture efficiency for iodine over the test duration. This versatile nature of chalcogels can provide an attractive option for the environmental remediation of the radionuclides associated with legacy wastes from nuclear weapons production as well as wastes generated during nuclear power production or nuclear fuel reprocessing.

Attributable to their low chemical durability, borate-based glasses have been demonstrated to convert rapidly to hydroxy-carbonated apatite (HCA), the inorganic component of bone. However, the effect of sol-gel processing on the bioactivity of borate-based glasses has not been investigated. In this study, the gel and glass forming abilities of six different borate-based glass formulations with borate content ranging from 36 to 61 mol % and based on a previously studied four component melt-derived glass system [(46.1)B 2 O 3 −(26.9)CaO−(24.4)Na 2 O−(2.6)P 2 O 5 ; mol %] were investigated. Compared to melt-quench, sol-gel processing fabricated nanoporous glass particles with at least 2 orders of magnitude greater values for specific surface areas and total pore volumes, which translated to dramatically higher aqueous interaction and ion release rates. Surprisingly, when immersed in simulated body fluid, HCA conversion was achieved in as little as 3 h for sol-gel derived borate based glasses, demonstrating a 25-fold increase in mineralization rate when compared to melt derived equivalents. The ability of the sol-gel derived borate-based glasses to rapidly convert to bone-like HCA holds promise in numerous potential tissue engineering applications, including the repair and augmentation of mineralized tissues.

Powders of a Sn2S3 chalcogen-based aerogel (chalcogel) were combined with powdered polyacrylonitrile (PAN) in different mass ratios (SnS33, SnS50, and SnS70; # = mass% of chalcogel), dissolved in dimethyl sulfoxide, and added dropwise to deionized water to form pellets of a porous PAN-chalcogel hybrid material. These pellets, along with pure powdered (SnSp) and granular (SnSg) forms of the chalcogel, were then used to capture iodine gas under both dynamic (dilute) and static (concentrated) conditions. Both SnSp and SnSg chalcogels showed very high iodine loadings at 67.2 and 68.3 mass%, respectively. The SnS50 hybrid sorbent demonstrated a high, although slightly reduced, maximum iodine loading (53.5 mass%) with greatly improved mechanical rigidity. In all cases, X-ray diffraction results showed the formation of crystalline SnI4 and SnI4(S8)2, revealing that the iodine binding in these materials is mainly due to a chemisorption process, although a small amount of physisorption was observed.

There is increasing focus on the development of bioactive scaffolds for tissue engineering and regenerative medicine that mimic the native nanofibrillar extracellular matrix. Solution blow spinning (SBS) is a rapid, simple technique that produces nanofibers with open fiber networks for enhanced cell infiltration. In this work, highly porous bioactive fibers were produced by combining SBS with thermally induced phase separation. Fibers composed of poly­(d,l-lactide) (PLA) and dimethyl carbonate were sprayed directly into a cryogenic environment and subsequently lyophilized, rendering them highly porous. The surface areas of the porous fibers were an order of magnitude higher in comparison with smooth control fibers of the same diameter (43.5 m2·g–1 for porous fibers produced from 15% w/v PLA in dimethyl carbonate) and exhibited elongated surface pores. Macroporous scaffolds were produced by spraying water droplets simultaneously with fiber formation, creating a network of fibers and ice microspheres, which act as in situ macroporosifiers. Subsequent lyophilization resulted in three-dimensional (3D) scaffolds formed of porous nanofibers with interconnected macropores due to the presence of the ice spheres. Nanobioactive glass was incorporated for the production of 3D macroporous, bioactive, therapeutic-ion-releasing scaffolds with potential applications in non-load-bearing bone tissue engineering. The bioactive characteristics of the fibers were assessed in vitro through immersion in simulated body fluid. The release of soluble silica ions was faster for the porous fibers within the first 24 h, with confirmation of hydroxyapatite on the fiber surface within 84 h.