Camphorquinone (CQ) is by far the most widely used visible-light photoinitiator in biomedical applications. Despite the fact that CQ is well established and has a good clinical acceptance, photoinitiating systems based on CQ have some drawbacks in particular poor water solubility and low photoreactivity. Here the synthesis and testing of a new camphorquinone derivative are described. Carboxylated-camphorquinone (CQCOOH) was synthesized using ketopinic acid as the starting material. The chemical structure of CQCOOH was verified by 1H-NMR, 1H–13C-COSY-NMR, FT-IR, mass spectroscopy, and UV–visible spectrophotometry. CQCOOH was used with an amine coinitiator and diphenyliodonium chloride (DPIC) accelerator as a visible light induced photoinitiating system for the preparation of hydrogels. CQCOOH exhibits a significantly higher photoreactivity compared to CQ with the same amine-DPIC system. Already after 5s exposure time, the polymer crosslinked with the CQCOOH-amine-DPIC system to form a hydrogel. Furthermore, higher crosslink density and better mechanical properties are observed compared to those hydrogels prepared with the CQ-amine-DPIC system. Experiments measuring the activity or integrity of cells (MTT and LDH assay, respectively) were performed to investigate the compatibility of the photoinitiating system components with human gingival fibroblast (HGF). According to these experiments neither CQCOOH, l-arginine nor N-phenylglycine as amine coinitiators have toxic effects even in high concentrations. In contrast, HGF cell viability is considerably decreased at DPIC-concentrations higher than 0.25%

Polyamines mimicking substances which occur naturally in biosilicas have been synthesized and show an accelerating effect on silica condensation, which depends on the chemical nature, the architecture (linear or branched), and the degree of polymerization.

A simple method for the functionalization of a common implant material (Ti6Al4V) with biodegradable, drug loaded chitosan-tripolyphosphate (CS-TPP) nanoparticles is developed in order to enhance the osseointegration of endoprostheses after revision operations. The chitosan used has a tailored degree of acetylation which allows for a fast biodegradation by lysozyme. The degradability of chitosan is proven via viscometry. Characteristics and degradation of nanoparticles formed with TPP are analyzed using dynamic light scattering. The particle degradation via lysozyme displays a decrease in particle diameter of 40% after 4 days. Drug loading and release is investigated for the nanoparticles with bone morphogenetic protein 2 (BMP-2), using ELISA and the BRE luciferase test for quantification and bioactivity evaluation. Furthermore, nanoparticle coatings on titanium substrates are created via spray-coating and analyzed by ellipsometry, scanning electron microscopy and X-ray photoelectron spectroscopy. Drug loaded nanoparticle coatings with biologically active BMP-2 are obtained in vitro within this work. Additionally, an in vivo study in mice indicates the dose dependent induction of ectopic bone growth through CS-TPP-BMP-2 nanoparticles. These results show that biodegradable CS-TPP coatings can be utilized to present biologically active BMP-2 on common implant materials like Ti6Al4V.