Papers by Keyword: Biomimetic

Abstract: Degenerative disc disease is an increasing problematic complication following lumbar fusion surgeries. Posterior lumbar interbody fusion (PLIF) is a well-established surgical method for spine stability following intervertebral disc removal. The position and number of titanium cages in PLIF are remain contingent on individual surgeon experience. Thus, a systemic investigation of the efficacy of titanium single mega cage versus two cages in treating degenerative lumbar spinal diseases is imperative. A biomechanical study was aimed to compare the stability achieved in PLIF through interbody reconstruction using a single mega cage (32 mm) Vs. a dual cage (22 mm). Normal intact finite element model of L3–L4 was developed based on computed tomography images from a healthy 27-year-old male volunteer. The study tested the intact model (Model A) and its surgically operated counterparts using four PLIF implantation methods: single transverse cage (Model B), single transverse cage with bone graft (Model C), dual transverse cage (Model D), and dual transverse cage with bone graft (Model E). Combined loads simulating physiological motions—flexion, extension, axial rotation, and lateral bending —were applied across all loading directions. The assessment includes all model range of motion (ROM), micromotion between the cage and endplate, and stress on the cage and internal fixation system (screw and rod). The ROM between Models B, C, D and E were consistently reduced by over 71% compared to intact Model A under all motion scenarios. Model D exhibited the highest peak stress of 115 MPa on the cage during flexion, surpassing Model C and E (Flexion) by fourfold. Model E demonstrated the lowest cage stress (20 MPa) during extension, outperforming the other models. Notably, Model E exhibited minimal endplate stress (2 MPa), cage stress (21 MPa), micromotion (13 µm) during extension, and screw-rod stress (56 MPa) during flexion, making it superior to other implantation methods. In the context of PLIF, Model E showed enhanced biomechanical stability, reducing ROM, stress on the endplates, cage, screw-rod system and micromotion. Alternatively, Model C may be a viable alternative in standard PLIF, especially in cases with limited intervertebral space, providing efficient clinical outcomes with shorter operative times and reduced costs and ease of implantation. Also, this computational study provides valuable understandings into optimizing cage implantation strategies for improved outcomes during PLIF.

Abstract: Titanium based metallic biomaterials for orthopedic implant applications are often associated with biocompatibility problems which can be ameliorated via proper surface modification strategies. Improving the hydrophilic nature of the titanium surface offers an effective strategy to sort out such limitations by intensifying the cellular activity. Development of titania as well as titanate layers on the titanium surface via alkali treatment represents an effective strategy to improve the hydrophilicity of native titanium surface. Inspired from nature, in the present work, we report the formation of three-dimensional (3D) hierarchical nanoflowers resembling Gomphrena globosa flowers developed on commercially pure titanium (cp-Ti) surface via a facile alkali treatment technique. X-ray diffraction studies evidenced anatase and rutile phases of TiO₂ confirming the development of titania on the surface. In addition to the TiO₂ phase, presence of titanate (Na₂Ti₃O₇) has also been observed as alkali treatment was conducted in NaOH solution. The hydrophilicity of the Ti surface has been enhanced after the alkali treatment as evidenced from wettability studies using static contact angle measurements. This increase in hydrophilicity is due to the enrichment of the surface by TiO₂ and titanate and increased roughness of nanoflower surface based on classical Wenzel law. In addition, the alkali-treated surface demonstrated an increased polar surface energy beneficial for biocompatible surfaces.

Abstract: Tooth loss due to periodontal disease, dental caries, trauma or a variety of genetic disorders causes an adverse inability in adult’s lives. It is proved that biodegradable composite scaffolds in dental tissue engineering could play crucial role. To inhibit bacterial colonization in dental structure noticeable research concerning the drug delivery approach has been administrated. Nanostructures retain and release drug molecules more efficiently and continuously than other microstructure. In the present research, composite electrospun nanofibers of polyurethane-Single-walled carbon nanotube (SWNT) by the different mass ratios of metronidazole benzoate were prepared. Physico-chemical characterization of scaffolds including Scanning electron microscopy (SEM), uniaxial tensile testing and Ultraviolet-Visible (UV-Vis) spectroscopy analysis was operated. Culture of dental pulp stem cells (DPSCs) to evaluate cells behavior was carried out. The role of nanofiber diameters and drug content on releasing profile of the scaffolds was investigated. The median diameter of the nanofibrous scaffold was reduced from 330 ± 4 to 120 ± 4 nm. Ultimate stress and Young modulus of the scaffolds by enhancement of drug content increased from 0.28 ± 0.05 up to the 1.8 ± 0.05 MPa and 0.87 ± 0.05 up to the 4.4 ± 0.05 Mpa respectively. According to the result, prolonged and continuous releasing profile of the drug molecules was achieved. As the content of the drug increased, the drug was released continuously. It means that two parameters of fiber's diameter and drug ratio affected the releasing behavior of composite structures. Polyurethane-SWNT scaffolds contained metronidazole benzoate presented appropriate support of DPSCs adhesion and proliferation and biomimetic architecture like the structure of dental ECM.

Abstract: The present study investigated the phase composition, the structural, morphological, and bioactivity properties of silicon- and carbonate-doped biomimetic hydroxyapatite synthesized by precipitation from aqueous solutions in the presence of different amounts of citrate ions. The X-ray diffraction and Fourier transform infrared spectroscopy analyses confirmed that all the samples exhibited single-phase. Base on the results of the morphological study, all the obtained samples consisted of porous agglomerated particles made up of tiny crystallites in the nanometer range. The change in structural order, as well as the decrease in particle size and degree of crystallinity result from the presence of citrate ions were revealed by X-ray diffraction, dynamic light scattering, and scanning electron microscopy analyses. Bioactivity properties of samples were studied by analyzing their bioresorbability in physiological saline (ω (NaCl) = 0.9%) and evaluating their solubility in SBF solution after a certain period of soaking time. The amount of the released Ca²⁺ ions was found to increase with the increasing concentration of citrate ions introduced in the synthesis process. The better solubility of material with the presence of citrate ions was beneficial in the growth of apatite on its surface that made produced material more biocompatible.

Abstract: The objective of this study is to evaluate the sulfuric acid resistance of the concrete coated with bacterial-glycocalix-based biomimetic coating mortar. The variation of the compressive strength and mass of the coated concrete since the specimen was immersed into an aqueous solution of 5 % sulfuric acid were 0.88 and 12 % at the age of 56 days, respectively, showing a superior deterioration resistance. As a result, it can be concluded that the developed biomimetic coating mortar possesses a great potential for enhancing the deterioration resistance performance of concrete.

Abstract: Influence of bovine serum albumin (BSA) concentration, soaking times and soaking temperatures during biomimetic co-deposition process of three dimensionally printed hydroxyapatite (3D printed HA) on weight change, phase composition and microstructure were studied. At 23°C, weight change of all samples monotonically increased with increasing soaking time regardless of BSA concentration used while the weight change initially increased, but leveled off later with increasing soaking time when using solution temperature of 37°C. At 50°C, weight change initially increased for up to 4 h and remained constant for up to 16 h where the weight decreased afterward. This decrease could be related to the competition between the dissolution of 3D printed HA, the deposition of new calcium phosphate crystals and the incorporation of BSA during biomimetic process at high temperatures. From X-ray diffraction, no influence in BSA concentration, time and temperature on the phase composition was observed. Scanning electron microscopy revealed the deposition of new plate-like calcium phosphate crystals on all 3D printed HA. Hydroxyapatite and octacalcium phosphate were found to be the main phases of all biomimetically BSA.

Abstract: A new amphiphilic bio-organic material was developed by conjugating the xanthine oxidase inhibitor, 2-amino-6-hydroxy-8-mercaptopurine (AMHP) with the naturally occurring polyphenol coumaric acid (CA). The formed product, AMHP-CA was allowed to self-assemble at a pH range of 4 through 8. Nanospheres or fibrous assemblies ranging upto micrometers in length were formed, depending upon growth conditions. Furthermore, it was found that the assemblies biomimetically formed gold nanoparticles on its surfaces resulting in AMHP-CA-AuNP hybrids. The DNA sensing ability of the AuNP bound AMHP-CA assemblies was investigated at varying concentrations by studying the changes in conformations of salmon milt DNA by CD spectroscopy and by examining live binding with surface plasmon resonance (SPR) analysis. AuNP bound AMHP-CA assemblies had significantly increased DNA sensing ability and SPR signal compared to binding interactions in the absence of AuNPs. Thus, in this study it was found that AMHP-CA-AuNP assemblies may function as biosensors for DNA detection.

Abstract: Calcium phosphate (CaP) ceramics, e.g. hydroxyapatite Ca₁₀(PO₄)₆(OH)₂ (HAP) and tricalcium phosphate Ca₃(PO₄)₂ (TCP), are widely employed in the field of bone tissue engineering due to their controlled biodegradability and excellent biocompatibility. In the present study, the chemical composition, microtexture and structure of CaP deposits on carbon fiber cloths (CFC) are investigated. Coatings of CaP or strontium-substituted calcium phosphate (Sr-CaP) on CFC are obtained by sono-electrodeposition process using cathodic polarization. At constant potential, the deposits consist in a biomimetic carbonated calcium-deficient hydroxyapatite (CaD-HAP), having a plate-like morphology with the possibility to control the Sr²⁺ incorporation. In orthopaedic field, CaP or Sr-CaP coated carbon fiber cloths offer new promising bioceramic materials for bone repair and regeneration.

Abstract: nanoscale rigid particles or plates are investigated for their reinforcing properties used as a binding material for holding together many long fiber composites. Very strong and light laminates can be made by layering thin sheets of rigid fibers (e.g. carbon fibers, glass fibers) with epoxy resin, for example, as a filler for spaces between fibers. Saint-Venant’s principle is concerned with assessing the effect of anisotropy on the decay of stresses with distance from the boundary of an elastic solid subjected to self-equilibrated end loads. The distance required for this transition is longer for rigid composites than for isotropic materials. The extra distance will allow bio-stress to be diffused to the boundary where end effects occur. This study is based on a biomimetic idea come from the mechanical behavior of biological materials as governed by underlying nanostructure, with the potential for synthesis into engineered materials. Mixing extremely small, rigid, randomly oriented nanoplates or nanotubes into the binding phase between the fibers is found to make the composite more isotropic near the ends and therefore mitigate damage.

Abstract: Gecko has a special micro hair on its foot to attach to a surface and climb walls. Mimicking its hair, easily detachable adhesive devices have been developed creating micro-structures on the surfaces. Adhesion strength of these devices changes with peeling direction. Therefore, this dependency enables a compatibility of strong adhesion and easy detachment. In this study, the effect of peeling speed on the adhesive strength of the devices is experimentally investigated.