A detailed study of the production of polysaccharide aerogel (bio-aerogel) particles from lab to pilot scale is surveyed in this article. An introduction to various droplets techniques available in the market is given and compared with the lab scale production of droplets using pipettes and syringes. An overview of the mechanisms of gelation of polysaccharide solutions together with non-solvent induced phase separation option is then discussed in the view of making wet particles. The main steps of particle recovery and solvent exchange are briefly described in order to pass through the final drying process. Various drying processes are overviewed and the importance of supercritical drying is highlighted. In addition, we present the characterization techniques to analyse the morphology and properties of the aerogels. The case studies of bio-aerogel (agar, alginate, cellulose, chitin, κ-carrageenan, pectin and starch) particles are reviewed. Potential applications of polysaccharide aerogel particles are briefly given. Finally, the conclusions summarize the prospects of the potential scale-up methods for producing bio-aerogel particles.

Due to the synergic feature of individual components in hybrid (nano)biomaterials, their application in regenerative medicine has drawn significant attention. Aiming to address all the current challenges of aerogel as a potent scaffold in bone tissue engineering application, we adopted a novel synthesis approach to synergistically improve the pore size regime and mechanical strength in the aerogel. The three-dimensional aerogel scaffold in this study has been synthesized through a versatile one-pot aqueous-based sol−gel hybridization/assembly of organosilane (tetraethyl orthosilicate) and silk fibroin (SF) biopolymer, followed by unidirectional freeze-casting of the as-prepared hybrid gel and supercritical drying. The developed ultralight silica-SF aerogel hybrids demonstrated a hierarchically organized porous structure with interesting honeycomb-shaped micromorphology and microstructural alignment (anisotropy) in varied length scales. The average macropore size of the hybrid aerogel lied in ∼0.5−18 μm and was systematically controlled with freeze-casting conditions. Together with high porosity (91−94%), high Young's modulus (∼4−7 MPa, >3 order of magnitude improvement compared to their pristine aerogel counterparts), and bone-type anisotropy in the mechanical compressive behavior, the silica-SF hybrid aerogel of this study acted as a very competent scaffold for bone tissue formation. The results of in vitro assessments revealed that the silica-SF aerogel is not only cytocompatible and nonhemolytic but also acted as an open porous microenvironment to trigger osteoblast cell attachment, growth, and proliferation on its surface within 14 days of incubation. Moreover, to support the in vitro results, in vivo bone formation within the aerogel implant in the bone defect site was studied. The X-ray radiology and microcomputed tomography analyses confirmed that a significant new bone tissue density formed in the defect site within 25 days of implantation. Also, in vivo toxicology studies showed a zero-toxic impact of the aerogel implant on the blood biochemical and hematological parameters. Finally, the study clearly shows the potential of aerogel as a bioactive and osteoconductive open porous cellular matrix for a successful osseointegration process.

We prepared from cellulose fibres monolithic aero-and cryogels. Cellulose is dissolved in hydrated calciumthiocyanate melt, gelled, aged and dried by several methods. The density of cellulose aerogels produced by supercritical drying is in the range between 10 and 60 kg/m 3 with a surface area of 200-220 m 2 /g. The cellulose cryogels produced by freeze drying exhibit a maximum surface area of 160 m 2 /g. Sputtered cellulose aero-and cryogels are examined with a scanning electron microscope. The results are discussed with respect to the literature and simple mathematical models.

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