Photodegradable Macromers and Hydrogels for Live Cell Encapsulation and Release
摘要:
Hydrogel scaffolds are commonly used as 3D carriers for cells because their properties can be tailored to match natural extracellular matrix. Hydrogels may be used in tissue engineering and regenerative medicine to deliver therapeutic cells to injured or diseased tissue through controlled degradation. Hydrolysis and enzymolysis are the two most common mechanisms employed for hydrogel degradation, but neither allows sequential or staged release of cells. In contrast, photodegradation allows external real-time spatial and temporal control over hydrogel degradation, and allows for staged and sequential release of cells. We synthesized and characterized a series of macromers incorporating photodegradbale ortho-nitrobenzyl (o-NB) groups in the macromer backbone. We formed hydrogels from these macromers via redox polymerization and quantified the apparent rate constants of degradation (k(app)) of each via photorheology at 370 nm, 10 mW/cm(2). Decreasing the number of aryl ethers on the o-NB group increases k(app), and changing the functionality from primary to seconday at the benzylic site dramatically increases k(app). Human mesenchymal stem cells (hMSCs) survive encapsulation in the hydrogels (90% viability postencapsulation). By exploiting the differences in reactivity of two different o-NB linkers, we quantitatively demonstrate the biased release of one stem cell population (green-fluoroescent protein expressing hMSCs) over another (red-fluorescent protein expressing hMSCs).
Process for preparing 4-nitrophenol derivatives of formula (IV) with high selectivity, which comprises converting phenols to diphenyl oxalate derivatives of formula (III) and conducting nitration reaction and hydrolysis to give said 4-nitrophenol derivatives. ##STR1## In the above formulae, R is, the same or different from each other, an alkyl group having 1 to 4 carbon atoms; a halogen atom; an alkoxy group having 1 to 4 carbon atoms; a formyl group; a nitrile group; --COOR.sup.1 (R.sup.1 is an alkyl group having 1 to 4 carbon atoms); --CONR.sup.2 R.sup.3 (R.sup.2 and R.sup.3 are, the same or different from each other, hydrogen atom(s) or alkyl group(s) having 1 to 4 carbon atoms); or --COR.sup.4 (R.sup.4 is an alkyl group having 1 to 4 carbon atoms), and R is not substituted at the 4-position of the phenyl ring and not substituted at the 2- and 6-positions of the phenyl ring at the same time, and, n is 1, 2 or 3.
Photodegradable Macromers and Hydrogels for Live Cell Encapsulation and Release
作者:Donald R. Griffin、Andrea M. Kasko
DOI:10.1021/ja305280w
日期:2012.8.8
Hydrogel scaffolds are commonly used as 3D carriers for cells because their properties can be tailored to match natural extracellular matrix. Hydrogels may be used in tissue engineering and regenerative medicine to deliver therapeutic cells to injured or diseased tissue through controlled degradation. Hydrolysis and enzymolysis are the two most common mechanisms employed for hydrogel degradation, but neither allows sequential or staged release of cells. In contrast, photodegradation allows external real-time spatial and temporal control over hydrogel degradation, and allows for staged and sequential release of cells. We synthesized and characterized a series of macromers incorporating photodegradbale ortho-nitrobenzyl (o-NB) groups in the macromer backbone. We formed hydrogels from these macromers via redox polymerization and quantified the apparent rate constants of degradation (k(app)) of each via photorheology at 370 nm, 10 mW/cm(2). Decreasing the number of aryl ethers on the o-NB group increases k(app), and changing the functionality from primary to seconday at the benzylic site dramatically increases k(app). Human mesenchymal stem cells (hMSCs) survive encapsulation in the hydrogels (90% viability postencapsulation). By exploiting the differences in reactivity of two different o-NB linkers, we quantitatively demonstrate the biased release of one stem cell population (green-fluoroescent protein expressing hMSCs) over another (red-fluorescent protein expressing hMSCs).
Insights into the modular design of kinase inhibitors and application to Abl and Axl
作者:Sameer Phadke、Lluis Lopez-Barcons、Nathalie Vandecan、Zhifen Wu、Taylor K. Johnson、Eric J. Lachacz、Sofia D. Merajver、Matthew B. Soellner
DOI:10.1039/d1md00296a
日期:——
Selectivity analysis and biological testing of a matched set of kinase inhibitors led to the identification of potent, selective inhibitors of Abl (wild-type and T315I) and Axl kinases.