The simplicity and versatility of hydrazone crosslinking has made it a strategy of choice for the conjugation of bioactive molecules. However, the labile nature of hydrazone linkages and reversibility of this coupling reaction restricts its full potential. Based on the fundamental understanding of hydrazone stability, this problem is circumvented by resonance‐stabilization of a developing N2 positive charge in a hydrazone bond. A novel chemistry is presented to develop a resilient hydrazone bond that is stable and non‐ reversible under physiological conditions. A carbodihydrazide (CDH) type hydrazide derivative of the biomolecule forms intrinsically stabilized hydrazone‐linkages that are nearly 15‐fold more stable at pH 5 than conventional hydrazone. This chemoselective coupling reaction is catalyst‐free, instantaneous, and virtually non‐cleavable under physiological conditions, therefore can serve as a catalyst‐free alternative to click chemistry. This novel crosslinking reaction is used to tailor a hyaluronan hydrogel, which delivered exceptional hydrolytic stability, mechanical properties, low swelling, and controlled enzymatic degradation. These desired characteristics are achieved without increasing the chemical crosslinking. The in vivo evaluation of this hydrogel revealed neo‐bone with highly ordered collagen matrix mimicking natural bone regeneration. The proximity ligation assay or PLA is used to detect blood vessels, which highlighted the quality of engineered tissue.

Releasibility of doxorubicin from drug-conjugates is believed to be a prerequisite for its anti-cancer activity. Here, a new glyco-drug approach that circumvents the releasibility restriction is reported, opening a new possibility to design efficient, target specific drug delivery system. It is discovered that stable amide coupling of doxorubicin (DOX) tohyaluronan (HA) shows dose dependent cytotoxicity to CD44 positive human coloncancer cells (HCT116) as compared to human breast cancer cells(MCF-7) and mouse fibroblast cells (NIH-3T3), which express less CD44 receptor. This direct conjugation approach is an easy scalable strategy that could be adopted to design innocuous anti-tumor nanoparticle formulations.

Through this systematic approach we present an unbiased overview of all published preclinical studies investigating the effect of bladder tissue engineering on cystometric bladder capacity. Preclinical research in healthy animals appears to show the feasibility of bladder augmentation by tissue engineering. However, in view of the disappointing clinical results based on healthy animal models new approaches should also be evaluated in preclinical models using dysfunctional/diseased bladders. This endeavor may aid in the development of clinically applicable tissue engineered bladder augmentation with satisfactory long-term outcome.

After implanting the tubular constructs a retroperitoneal tunnel was formed that functioned as a urinary conduit in most cases. Improved large tubular scaffolds may generate alternatives to gastrointestinal tissue for urinary diversion.

In the field of regenerative medicine, various types of biodegradable and nonbiodegradable scaffolds have been developed for urinary tract tissue-engineering applications. Naturally derived or synthetic materials have been tested to determine their properties and their effectiveness. However, the majority of the current literature focuses on the reconstruction of the urethra, urinary diversion, and urinary bladder, while limited data have been published regarding the use of biomaterials in ureteral reconstruction. Tissue engineering might offer alternative and less invasive therapeutic options for long ureteral defects compared with the current surgical reconstructive techniques and their potential complications. In this article, we aimed to review the literature regarding ureteral tissue engineering through a Medline search and describe new potential options for future clinical applications. We concluded that the available literature is inconclusive since the superiority of a specific scaffold has not been demonstrated and the latest developments of regenerative medicine have not been evaluated in ureteral tissue engineering yet.