Chitosan-recombinamer layer-by-layer coatings for multifunctional implants

Producción CientíficaThe main clinical problems for dental implants are (1) formation of biofilm around the implant—a condition known as peri-implantitis and (2) inadequate bone formation around the implant—lack of osseointegration. Therefore, developing an implant to overcome these problems is of significant interest to the dental community. Chitosan has been reported to have good biocompatibility and anti-bacterial activity. An osseo-inductive recombinant elastin-like biopolymer (P-HAP), that contains a peptide derived from the protein statherin, has been reported to induce biomineralization and osteoblast differentiation. In this study, chitosan/P-HAP bi-layers were built on a titanium surface using a layer-by-layer (LbL) assembly technique. The difference in the water contact angle between consecutive layers, the representative peaks in diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), X-ray photoelectron spectroscopy (XPS), and the changes in the topography between surfaces with a different number of bi-layers observed using atomic force microscopy (AFM), all indicated the successful establishment of chitosan/P-HAP LbL assembly on the titanium surface. The LbL-modified surfaces showed increased biomineralization, an appropriate mouse pre-osteoblastic cell response, and significant anti-bacterial activity against Streptococcus gordonii, a primary colonizer of tissues in the oral environmentMinisterio de Economía, Industria y Competitividad (Project MAT2013-42473-R and MAT2015-68901R)Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA244U13, VA313U14 and VA015U16

In vitro degradation and in vivo biocompatibility of chitosan-poly(butylene succinate) fiber mesh scaffolds

In tissue engineering, the evaluation of the host response to the biomaterial implantation must be assessed to determine the extent of the inflammatory reaction. We studied the degradation of poly(butylene succinate) and chitosan in vitro using lipase and lysozyme enzymes, respectively. The subcutaneous implantation of the scaffolds was performed to assess tissue response. The type of inflammatory cells present in the surrounding tissue, as well as within the scaffold, was determined histologically and by immunohistochemistry. In the presence of lipase or lysozyme, the water uptake of the scaffolds increased. Based on the weight loss data and scanning electron microscopy analysis, the lysozyme combined with lipase had a notable effect on the in vitro degradation of the scaffolds. The in vivo implantation showed a normal inflammatory response, with presence of neutrophils, in a first stage, and macrophages, lymphocytes, and giant cells in a later stage. Vascularization in the surrounding tissue and within the implant increased with time. Moreover, the collagen deposition increased with time inside the implant. In vivo, the scaffolds maintained the structural integrity. The degradation in vitro was faster and greater compared to that observed in vivo within the same time periods.Ana R Costa-Pinto was supported by the scholarship SFRH/24735/2005 from the Portuguese “Fundação para a Ciência e a Tecnologia” (FCT). This work was partially supported by the European Network of Excellence EXPERTISSUES (NMP3-CT-2004-500283) and FCT funded project Maxbone (PTDC/ SAU-ENB/115179/2009)

Silane grafted biosourced melanin: A sustainable approach for nanobiosensing applications

Nanotechnology has revolutionized areas of biotechnology owing to its multidiversified applications, improved sensitivity, surface size, and cost. In the past years, some issues have arisen regarding the impact of nanomaterials on the environment and human health. In this regard, there is a growing interest in identifying natural and sustainable nanostructured biomaterials as an alternative to toxic petrochemical derived materials. The most commonly used materials in nanobiotechnology applications possess inherent limitations regarding biocompatibility, which leads to foreign-body response at the implantation site, causing a rejection of the implant. In parallel, the recovery of byproducts from other industries and their transformation into valuable resources have been key factors in the circular economy. Given that, there is urgency to move toward sustainable research and green nanotechnologies with an undeniable biocompatibility. Herein, we propose a design based on natural melanin nanoparticles (MNPs) obtained from the ink sacs of Sepia officinalis, a waste product from the food industry, grafted with silane (MNPs GPTMS) for biomedical applications. The design, characterization of both physical and chemical properties, and biological properties of the MNPs GPTMS are reported. The silane, (3-glycidyloxypropyl)trimethoxysilane, allows facile functionalization of different bioreceptors onto the surface of MNPs GPTMS, herein demonstrated with antibodies and an enzyme. Cellular viability studies confirmed the cytocompatibility of MNPs GPTMS and hemocompatibility of 50 μg/mL. The engineered MNPs GPTMS provide a powerful, sustainable, and biocompatible biomaterial-based tool for specific bioreceptor targeting molecules that can be used in diverse biomedical field applications such as nanobiosensing.FCT -Fundação para a Ciência e a Tecnologia(Norte-01-0145-FEDER-022190