This Review is an overview of the unique characteristics of cyclodextrin in forming an inclusion complex via host-guest noncovalent interactions. The modification of cyclodextrin advances its application as a pharmaceutical solubilizer, fabrication of functional molecular machines such as polyrotaxane, polypseudorotaxane, and polycatenanes and grafting of cyclodextrin with different linear, branched chain polymers. The different stimuli-based supramolecular assemblies involving cyclodextrin as a key mediator with linked triggering responses on payload release is highlighted. In addition, the applications of cyclodextrin in diagnostic imaging and medical devices is briefly demonstrated. Cyclodextrin is a relatively low cost, biocompatible, biodegradable, and highly explored material with low toxicity for drug formulation, drug delivery, and wide varieties of other biomedical applications such as those in medical devices fabrication, biosensor, tissue engineering, and bio-imaging. The toxicological profile of cyclodextrin is well established and safe for human consumption in food and medicine.
MMC, the addition of inert polydispersed macromolecules in the culture media, effectively emulates the dense in vivo extracellular space, resulting in amplified deposition of ECM in vitro and subsequent production of cohesive, ECM-rich living substitutes.
Therapeutic strategies based on the principles of tissue engineering by self-assembly put forward the notion that functional regeneration can be achieved by utilising the inherent capacity of cells to create highly sophisticated supramolecular assemblies. However, in dilute ex vivo microenvironments, prolonged culture time is required to develop an extracellular matrix-rich implantable device. Herein, we assessed the influence of macromolecular crowding, a biophysical phenomenon that regulates intra- and extra-cellular activities in multicellular organisms, in human corneal fibroblast culture. In the presence of macromolecules, abundant extracellular matrix deposition was evidenced as fast as 48 h in culture, even at low serum concentration. Temperature responsive copolymers allowed the detachment of dense and cohesive supramolecularly assembled living substitutes within 6 days in culture. Morphological, histological, gene and protein analysis assays demonstrated maintenance of tissue-specific function. Macromolecular crowding opens new avenues for a more rational design in engineering of clinically relevant tissue modules in vitro.
The regeneration of cells and cell sheets mediated by thermoresponsive substrates represents an important and ever growing area in tissue engineering. This review seeks to track the development of this field from inception to the present day by highlighting the most significant breakthroughs as well as focusing on important physical and chemical characterization of substrates produced for this specific purpose. Furthermore, a critical evaluation encompassing the advantages and disadvantages of different techniques used for producing such surfaces will be included as well as suggestions for possible future directions.
Cell-based scaffold-free therapies seek to develop in vitro organotypic three-dimensional (3D) tissue-like surrogates, capitalising upon the inherent capacity of cells to create tissues with efficiency and sophistication that is still unparalleled by human-made devices. Although automation systems have been realised and (some) success stories have been witnessed over the years in clinical and commercial arenas, in vitro organogenesis is far from becoming a standard way of care. This limited technology transfer is largely attributed to scalability-associated costs, considering that the development of a borderline 3D implantable device requires very high number of functional cells and prolonged ex vivo culture periods. Herein, we critically discuss advancements and shortfalls of scaffold-free cell-based tissue engineering strategies, along with pioneering concepts that have the potential to transform regenerative and reparative medicine.
The definitive goal of this research is to develop protein-based scaffolds for use in soft tissue regeneration, particularly in the field of dermal healing. The premise of this investigation was to characterize the mechanical properties of gelatin cross-linked with microbial transglutaminase (mTGase) and to investigate the cytocompatibility of mTGase cross-linked gelatin. Dynamic rheological analysis revealed a significant increase in the storage modulus and thermal stability of gelatin after cross-linking with mTGase. Static, unconfined compression tests showed an increase in Young's modulus of gelatin gels after mTGase cross-linking. A comparable increase in gel strength was observed with 0.03% mTGase and 0.25% glutaraldehyde cross-linked gelatin gels. In vitro studies using 3T3 fibroblasts indicated cytotoxicity at a concentration of 0.05% mTGase after 72 h. However, no significant inhibition of cell proliferation was seen with cells grown on lower concentrations of mTGase cross-linked gelatin substrates. The mechanical improvement and cytocompatibility of mTGase crosslinked gelatin suggests mTGase has potential for use in stabilizing gelatin gels for tissueengineering applications.
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