Transition Metal Complexes with Tridentate Schiff Bases (O N O and O N N) Derived from Salicylaldehyde: An Analysis of Their Potential Anticancer Activity

Although it is known that the first case of cancer was recorded in ancient Egypt around 1600 BC, it was not until 1917 during the First World War and the development of mustard gas that chemotherapy against cancer became relevant; however, its properties were not recognised until 1946 to later be used in patients. In this sense, the use of metallopharmaceuticals in cancer therapy was extensively explored until the 1960s with the discovery of cisplatin and its anticancer activity. From that date to the present, the search for more effective, more selective metallodrugs with fewer side effects has been an area of continuous exploration. Efforts have led to considering a wide variety of metals from the periodic table, mainly from the d-block, as well as a wide variety of organic ligands, preferably with proven biological activity. In this sense, various research groups have found an ideal binder in Schiff bases, since their raw materials are easily accessible, their synthesis conditions are friendly and their denticity can be manipulated. Therefore, in this review, we have explored the anticancer and antitumor activity reported in the literature for coordination complexes of d-block metals coordinated with tridentate Schiff bases (O N O and O N N) derived from salicylaldehyde. For this work, we have used the main scientific databases CCDC® and SciFinder®.

A microporous surface containing Si3N4/Ta microparticles of PEKK exhibits both antibacterial and osteogenic activity for inducing cellular response and improving osseointegration

As an implantable biomaterial, polyetherketoneketone (PEKK) exhibits good mechanical strength but it is biologically inert while tantalum (Ta) possesses outstanding osteogenic bioactivity but has a high density and elastic modulus. Also, silicon nitride (SN) has osteogenic and antibacterial activity. In this study, a microporous surface containing both SN and Ta microparticles on PEKK (STP) exhibiting excellent osteogenic and antibacterial activity was created by sulfonation. Compared with sulfonated PEKK (SPK) without microparticles, the surface properties (roughness, surface energy, hydrophilicity and protein adsorption) of STP significantly increased due to the SN and Ta particles presence on the microporous surface. In addition, STP also exhibited outstanding antibacterial activity, which inhibited bacterial growth in vitro and prevented bacterial infection in vivo because of the presence of SN particles. Moreover, the microporous surface of STP containing both SN and Ta particles remarkably induced response (e.g., proliferation and differentiation) of rat bone mesenchymal stem (rBMS) cells in vitro. Furthermore, STP significantly improved new bone regeneration and osseointegration in vivo. Regarding the induction of cellular response in vitro and improvement of osseointegration in vivo, the microporous surface containing Ta was better than the surface with SN particles. In conclusion, STP with optimized surface properties activated cellular responses in vitro, enhanced osseointegration and prevented infection in vivo. Therefore, STP possessed the dual biofunctions of excellent osteogenic and antibacterial activity, showing great potential as a bone substitute.

•Microporous surface containing SN/Ta microparticles on PEKK (STP) was created.

•Surface performances (e.g., roughness) of STP were significantly increased.

•STP exhibited antibacterial activity in vitro and prevented infection in vivo.

•STP remarkably induced response of bone mesenchymal stem cells in vitro.

•STP obviously improved bone regeneration and osseointegration in vivo.

Tantalum(v) peroxido complexes as phosphatase inhibitors: a comparative study vis-a-vis peroxidovanadates

Peroxido Ta(v) complexes are found to be more effective as inhibitors of wheat thylakoid acid phosphatase vis-à-vis their V containing analogues. In addition, these compounds showed unique resistance towards degradation in the presence of catalase.

Implantable PEKK/tantalum microparticles composite with improved surface performances for regulating cell behaviors, promoting bone formation and osseointegration

Polyetherketoneketone (PEKK) exhibits admirable biocompatibility and mechanical performances but bioinert while tantalum (Ta) possesses excellent osteogenesis and osseointegration but high elastic modulus and density, and processing is too difficult and expensive. In the present study, combining of the advantages of both PEKK and Ta, implantable composites of PEKK/Ta were fabricated by blending PEKK with Ta microparticles of 20 v% (PT20) and 40 v% (PT40) content. In comparison with PT20 and PEKK, the surface hydrophilicity, surface energy, roughness and proteins adsorption as well as mechanical performances of PT40 significantly increased because of the higher Ta particles content in PEKK. Furthermore, PT40 exhibited the mechanical performances (e.g., compressive strength and modulus of elasticity) close to the cortical bone of human. Compared with PT20 and PEKK, PT40 with higher Ta content remarkably enhanced the responses (including adhesion, proliferation and osteogenic differentiation) of MC3T3-E1 cells in vitro. Moreover, PT40 markedly improved bone formation as well as osseointegration in vivo. In short, incorporation of Ta microparticles into PEKK created implantable composites with improved surface performances, which played key roles in stimulating cell responses/bone formation as well as promoting osseointegration. PT40 might have great potential for bear-loading bone substitute.

Gamma-ray irradiation effects on tantalum thin film for improved mechanical compatibility and cytocompatibility

In this work, tantalum thin films were prepared on titanium substrates by an ion beam sputtering method. Tantalum thin films were irradiated by gamma-ray with different total dose levels. The effect of irradiation on the phase composition, microstructure, surface morphology, and chemical resistance were analyzed. Besides, in vitro cytocompatibility of tantalum films treated with different radiation doses were evaluated via 3T3-E1 cells. Experimental results showed that higher radiation dose resulted in reductions in crystalline nature, denser morphology, lower elastic modulus, less oxygen vacancies and better corrosion resistance. Additionally, 3T3-E1 cells adhered and spread well on the surface of tantalum film with irradiation exposure to 10 kGy. The dense surface morphology, less density of chemical defects and amorphous phase produced by the gamma-ray irradiation played a major role in the improvement of mechanical compatibility, electrochemical stability property along with the cytocompatibility of the tantalum films.

The influence of tantalum on human cell lineages important for healing in soft-tissue reattachment surgery: an in-vitro analysis

BACKGROUND

Porous tantalum is currently used in orthopaedic surgery for a variety of indications including soft tissue re-attachment. However, the clinical results have been variable and a previous laboratory study has suggested that tantalum may actually inhibit chick tendon fibroblasts. The influence of tantalum on human cell-types involved in soft tissue re-attachment has not been defined.

METHODS

Human fibroblasts, human osteoblasts and human mesenchymal stem cells were plated on glass cover slips, half of which were coated with tantalum. Cell numbers were assessed at 1, 2, 7 and 14 days using Cyquant® assay. Cell adhesion and morphology were assessed using light microscopy at 7, 14 and 28 days. To reduce the effect of an expected rate of error, n = 4 was utilised for each cell type and the experiment was repeated twice.

RESULTS

Statistically similar numbers of human osteoblasts and human mesenchymal stem cells were present at 14 days on tantalum-coated and uncoated glass cover slips, revealing no inhibitory effect on cell proliferation. More than double the number of human fibroblasts was seen on tantalum-coated cover slips at that time point (compared to controls), which was statistically significant (p < 0.0001). Morphological assessment revealed normal cell spreading and adhesion on both substrates at all time points.

CONCLUSIONS

In vitro study demonstrates that Tantalum causes a significant increase in the proliferation of human fibroblasts with no quantifiable negative effects seen on fibroblast behaviour after 28 days culture. Furthermore, tantalum does not exert any inhibitory effects on the proliferation or behaviour of human osteoblasts or human mesenchymal stem cells. Tantalum could be an appropriate biomaterial for use in situations where soft tissue requires direct reattachment to implants and may stimulate soft tissue healing.

[Research progress of porous tantalum in bone tissue engineering]

Objective

To review the basical research progress of porous tantalum in bone tissue engineering.

Methods

The related basical research in fabrication, cytobiology, and surface modification of porous tantalum was reviewed and analyzed.

Results

The outstanding physiochemical properties of porous tantalum granted its excellent performance in biocompatibility and osteointegration, as well as promoting cartilage and tendon tissue restoration. However, the clinical utilization of porous tantalum is somehow greatly limited by the complex and rigid commercial fabrication methods and extraordinary high cost. Along with the publication of novel fabrication and surface modification technology, the application of porous tantalum will be more extensive, the promotion in bone tissue regeneration will be more prominent.

Conclusion

Porous tantalum has advantage in bone defect restoration, and significant breakthrough technology is needed in fabrication methods and surface modification.

Reduced fibrous capsule formation at nano-engineered silicone surfaces via tantalum ion implantation

Nano-engineered surface of silicone implant improves the biocompatibility and suppresses the fibrous capsule formation which is the most common side effect of polymeric implants.

Poly(ethylene glycol)/chitosan/sodium glycerophosphate gel replaced the joint capsule with slow-release lubricant after joint surgery

Body fluid is normally the only lubricant after joint replacement surgery, but wear problems have occurred because body fluid has poor lubrication ability. However, traditional lubricant would be diluted by body fluids and then absorbed by the human body. Therefore, an injectable gel with the ability to slow-release lubricant was designed to replace the joint capsule. The proposed gel, poly(ethylene glycol)/chitosan/sodium glycerophosphate (PEG/CS/GP) composite gel was then tested. The tribology results showed that the PEG/CS/GP gel had excellent slow-release properties, especially under pressure, and the PEG played an important role in improving the gel's rheological and mechanical properties. Moreover, this study revealed that the release solution had a good lubrication effect because the PEG and GP could crosslink via the hydrogen bond effect.

A cytotoxic tantalum(v) half-sandwich complex: a new challenge for metal-based anticancer agents

The new and pharmacologically promising electroneutral half-sandwich Ta(v)-dichlorido Schiff-base complex was described.

Laser textured Co-Cr-Mo alloy stored chitosan/poly(ethylene glycol) composite applied on artificial joints lubrication

Arthroplasty brings the wear problems because of body fluid has poor performance as lubricant. Lubricant which is used in artificial joints will rapidly degrade and be absorbed by human body after injecting. To prolong the lubricant's effectiveness, this study prepared chitosan/poly(ethylene glycol) (CS/PEG) and textures to play a role in joint lubrication and wear protection. Chitosan (CS) and poly(ethylene glycol) which have biocompatibility and biodegradability properties can be used in human body. The tribological results shown that CS/PEG sol has excellent performance when this sol was composed by 2wt% CS and 30wt% PEG, the average friction coefficient below 0.016 under the condition of 30-90N load (pressure 4.2-12.6MPa). In this study, CS/PEG was added in the texture of artificial joints, then the surfaces of the CS/PEG formed gel via NaOH solidification effect. The CS/PEG gel film could prevent the CS/PEG sol from diluting in body fluid. Meanwhile, FT-IR, XRD, UV/vis and Raman spectra revealed that CS associated with PEG via hydrogen bond effect may form a particular structure, which leaded the good tribological performance. This study provides a new, simple and green approach to enhance tribological performances of artificial joints.

Laser-textured surface storing a carbon dots/poly(ethylene glycol)/chitosan gel with slow-release lubrication effect

Arthroplasty presents wear problems because body fluid, as the only lubricant, has poor performance.