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Injectable, tissue mimetic, bioactive, and biodegradable hydrogels offer less invasive regeneration and repair of tissues. The monitoring swelling and in vitro degradation capacities of hydrogels are highly important for drug delivery and tissue regeneration processes. Bioactivity of bone tissue engineered constructs in terms of mineralized apatite formation capacity is also pivotal. We have previously reported in situ forming chitosan‐based injectable hydrogels integrated with hydroxyapatite and heparin for bone regeneration, promoting angiogenesis. These hydrogels were functionalized by glycerol and pH to improve their mechano‐structural properties. In the present study, functionalized hybrid hydrogels were investigated for their swelling, in vitro degradation, and bioactivity performances. Hydrogels have degraded gradually in phosphate‐buffered saline (PBS) with and without lysozyme enzyme. The percentage weight loss of hydrogels and their morphological and chemical properties, and pH of media were analyzed. The swelling ratio of hydrogels (55%–68%(wt), 6 h of equilibrium) indicated a high degree of cross‐linking, can be suitable for controlled drug release. Hydrogels have gradually degraded reaching to 60%–70% (wt%) in 42 days in the presence and absence of lysozyme, respectively. Simulated body fluid (SBF)‐treated hydrogels containing hydroxyapatite‐induced needle‐like carbonated‐apatite mineralization was further enhanced by heparin content significantly.

Injectable, tissue mimetic, bioactive, and biodegradable hydrogels offer less invasive regeneration and repair of tissues. The monitoring swelling and in vitro degradation capacities of hydrogels are highly important for drug delivery and tissue regeneration processes. Bioactivity of bone tissue engineered constructs in terms of mineralized apatite formation capacity is also pivotal. We have previously reported in situ forming chitosan‐based injectable hydrogels integrated with hydroxyapatite and heparin for bone regeneration, promoting angiogenesis. These hydrogels were functionalized by glycerol and pH to improve their mechano‐structural properties. In the present study, functionalized hybrid hydrogels were investigated for their swelling, in vitro degradation, and bioactivity performances. Hydrogels have degraded gradually in phosphate‐buffered saline (PBS) with and without lysozyme enzyme. The percentage weight loss of hydrogels and their morphological and chemical properties, and pH of media were analyzed. The swelling ratio of hydrogels (55%–68%(wt), 6 h of equilibrium) indicated a high degree of cross‐linking, can be suitable for controlled drug release. Hydrogels have gradually degraded reaching to 60%–70% (wt%) in 42 days in the presence and absence of lysozyme, respectively. Simulated body fluid (SBF)‐treated hydrogels containing hydroxyapatite‐induced needle‐like carbonated‐apatite mineralization was further enhanced by heparin content significantly.

Injectable, tissue mimetic, bioactive, and biodegradable hydrogels offer less invasive regeneration and repair of tissues. The monitoring swelling and in vitro degradation capacities of hydrogels are highly important for drug delivery and tissue regeneration processes. Bioactivity of bone tissue engineered constructs in terms of mineralized apatite formation capacity is also pivotal. We have previously reported in situ forming chitosan‐based injectable hydrogels integrated with hydroxyapatite and heparin for bone regeneration, promoting angiogenesis. These hydrogels were functionalized by glycerol and pH to improve their mechano‐structural properties. In the present study, functionalized hybrid hydrogels were investigated for their swelling, in vitro degradation, and bioactivity performances. Hydrogels have degraded gradually in phosphate‐buffered saline (PBS) with and without lysozyme enzyme. The percentage weight loss of hydrogels and their morphological and chemical properties, and pH of media were analyzed. The swelling ratio of hydrogels (55%–68%(wt), 6 h of equilibrium) indicated a high degree of cross‐linking, can be suitable for controlled drug release. Hydrogels have gradually degraded reaching to 60%–70% (wt%) in 42 days in the presence and absence of lysozyme, respectively. Simulated body fluid (SBF)‐treated hydrogels containing hydroxyapatite‐induced needle‐like carbonated‐apatite mineralization was further enhanced by heparin content significantly.

Hard and soft tissue repair and regeneration require multiple surgical interventions, as very often-repeated clinical procedures are required. In addition, insufficient vascularisation remains as the main challenge for bone repair and regeneration. Therefore, bone regeneration via minimal invasive biomaterials promoting angiogenesis by bioactive agents are very much considered at present. Hereof, among new generation biomaterials, in-situ forming stimuli responsive injectable hydrogels have been of interest both in clinical and non-clinical communities. In this study, novel pH and thermosensitive in-situ formed injectable hydrogel compositions were developed by a heparin (Hep) functionalised chitosan (CS) polymer matrix integrated with a nonsintered hydroxyapatite (HA) system neutralised with sodium bicarbonate (NaHCO3). Due to designed bioactive features, CS/HA/Hep hydrogels are desired to ensure strong chemical anchorage and biological bridging by promoting vascular network formation at bone tissue defects due to the potential binding capacity of Hep for endogenous angiogenic growth factors and proteins. The production and optimisation of hydrogel compositions and their modification for pre-sterile synthesis technique with glycerol additive for enhancing mechanical properties meanwhile were investigated. The versatile properties of hydrogels were investigated for many aspects, such as injectability, gelation, rheology, mechanical properties, degradability, bioactivity, biocompatibility and angiogenesis. Hydrogel compositions showed facile injectability allowing suitable manual injection by 21 gauge (G) minimum needle thickness, and fast gelation at average body temperature (37 °C). In modified hydrogels, slight pH increment at solutions above 6.4 provided interpenetrating cross-linked morphology starting gelation in 2-3 minutes with enhanced elasticity, and mechanical strength. Hydrogels showed great bioactivity confirmed in Simulated Body Fluid (SBF) by forming m

Hard and soft tissue repair and regeneration require multiple surgical interventions, as very often-repeated clinical procedures are required. In addition, insufficient vascularisation remains as the main challenge for bone repair and regeneration. Therefore, bone regeneration via minimal invasive biomaterials promoting angiogenesis by bioactive agents are very much considered at present. Hereof, among new generation biomaterials, in-situ forming stimuli responsive injectable hydrogels have been of interest both in clinical and non-clinical communities. In this study, novel pH and thermosensitive in-situ formed injectable hydrogel compositions were developed by a heparin (Hep) functionalised chitosan (CS) polymer matrix integrated with a nonsintered hydroxyapatite (HA) system neutralised with sodium bicarbonate (NaHCO3). Due to designed bioactive features, CS/HA/Hep hydrogels are desired to ensure strong chemical anchorage and biological bridging by promoting vascular network formation at bone tissue defects due to the potential binding capacity of Hep for endogenous angiogenic growth factors and proteins. The production and optimisation of hydrogel compositions and their modification for pre-sterile synthesis technique with glycerol additive for enhancing mechanical properties meanwhile were investigated. The versatile properties of hydrogels were investigated for many aspects, such as injectability, gelation, rheology, mechanical properties, degradability, bioactivity, biocompatibility and angiogenesis. Hydrogel compositions showed facile injectability allowing suitable manual injection by 21 gauge (G) minimum needle thickness, and fast gelation at average body temperature (37 °C). In modified hydrogels, slight pH increment at solutions above 6.4 provided interpenetrating cross-linked morphology starting gelation in 2-3 minutes with enhanced elasticity, and mechanical strength. Hydrogels showed great bioactivity confirmed in Simulated Body Fluid (SBF) by forming m

In this thesis, the nature of the Sn94- in solution and its reactivity with transition metal atoms and electrophiles have been studied. The Sn94- ion is a very strong Brønsted base that deprotonates en to form the Sn9H3- ion and is a potent ion sequestering agent that competes with 2,2,2-crypt for binding K+. The Sn9H3- ion has a pKa in a range of 32.2– 44 in dmso and can be reversibly interconverted to K3Sn9- through addition of K+ and base. Addition of K+ to Sn9H3- in the absence of base gives the proposed coupled Sn9–Sn96- dimer. The diamagnetic Sn9H3- ion was mischaracterized as the Sn93- paramagnetic radical in numerous publications since 1983. The Sn9H3- ion reacts with Ni(cod)2 and Pd(PPh3)4 complexes and give the M@Sn9H3- clusters (M= Ni, Pd). The Ni@Sn9H3- ion reacts with (arene)M(CO)3 complexes to form is the Ni@Sn9M(CO)34- ion. Endohedral d–10 atoms do not affect the pKa's of the hydrido clusters, whereas coordination of M(CO)3 group (M= Cr, Mo) significantly increases the acidity. The M@Sn9SnCy33- ions, where M= Ni and Pd, have been prepared with two different synthetic routes from Ni@Sn9H3- and Sn9SnCy33- ions, respectively. The Ni@Sn9H3- ion reacts with Cy3SnCl and gives the Ni@Sn9SnCy33- ion. The Sn9SnCy33- ion reacts with Pd(PPh3)