A biologically active, high-strength tissue adhesive is needed for numerous medical applications in tissue engineering and regenerative medicine. Integration of biomaterials or implants with surrounding native tissue is crucial for both immediate functionality and long-term performance of the tissue. Here, we use the biopolymer chondroitin sulphate (CS), one of the major components of cartilage extracellular matrix, to develop a novel bioadhesive that is readily applied and acts quickly. CS was chemically functionalized with methacrylate and aldehyde groups on the polysaccharide backbone to chemically bridge biomaterials and tissue proteins via a twofold covalent link. Three-dimensional hydrogels (with and without cells) bonded to articular cartilage defects. In in vitro and in vivo functional studies this approach led to mechanical stability of the hydrogel and tissue repair in cartilage defects.

The effect of 500 eV electrons on nanometer scale thick films of trimethyl(methylcyclopentadienyl)platinum(IV) (MeCpPtIVMe3), were studied in situ, under ultrahigh vacuum conditions using a combination of temperature-programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), mass spectrometry, and reflection absorption infrared spectroscopy. TPD results revealed the presence of a monolayer state, with a desorption energy >10 kJ mol−1 larger than the multilayer. XPS data indicate that electron beam induced decomposition of adsorbed MeCpPtIVMe3 produced a carbonaceous film that contained Pt atoms in an electronic state intermediate between metallic Pt and Pt(IV). In addition to Pt(IV) reduction, electron beam irradiation was also accompanied by the evolution of methane and hydrogen from the adsorbate layer and the loss of C−H groups. The rate of Pt(IV) reduction and methane production and the loss of C−H groups from the film were all proportional to the MeCpPtIVMe3 coverage and the incident electron flux. Rate constants for all three processes were comparable, yielding an average reaction cross section of 2.2 × 10−16 cm2 for 500 eV electrons. Changes in the chemical composition of the adsorbate layer as a result of electron beam irradiation were consistent with a process in which one carbon atom desorbs for each MeCpPtIVMe3 molecule that decomposes. A comparison of the gas-phase products observed during the electron irradiation of adsorbed MeCpPtIVMe3 and CpPtIVMe3 support the idea that electron-stimulated decomposition of these platinum precursors involves by Pt−CH3 bond cleavage.