Update on the use of 45S5 bioactive glass in the treatment of bone defects in regenerative medicine

Bone regeneration is a critical area in regenerative medicine,particularly in orthopedics,demanding effective biomedical materials for treating bone defects.45S5 bioactive glass(45S5 BG)is a promising material because of its osteoconductive and bioactive properties.As research in this field continues to advance,keeping up-to-date on the latest and most successful applications of this material is imperative.To achieve this,we conducted a comprehensive search on Pub-Med/MEDLINE,focusing on English articles published in the last decade.Our search used the keywords“bioglass 45S5 AND bone defect”in combination.We found 27 articles,and after applying the inclusion criteria,we selected 15 studies for detailed examination.Most of these studies compared 45S5 BG with other cement or scaffold materials.These comparisons demonstrate that the addition of various composites enhances cellular biocompatibility,as evidenced by the cells and their osteogenic potential.Moreover,the use of 45S5 BG is enhanced by its antimicrobial properties,opening avenues for additional investigations and applications of this biomaterial.

Biocompatibility of KLD-12 Peptide Hydrogel as a Scaffold in Tissue Engineering of Intervertebral Discs in Rabbits

KLD-12 peptide with a sequence of AcN-KLDLKLDLKLDL-CNH2 was synthesized and its biocompatibility was assessed in animals. Rabbit MSCs were cultured in the hydrogel for 2 weeks. Live cells were counted by using Calcein-AM/P1 fluorescence staining. MTT was employed to assess the viability of MSCs cultured in KLD-12 peptide solution of 0.01%, 0.03%, and 0.05%. Hemolysis test, skin irritation test and implantation test were conducted to evaluate its biocompatibility with host tissues. Our results demonstrated that the MSCs in hydrogel grew well and maintained round shape. Cell survival rate was 92.15% （mean： 92.15%±1.17%） at the 7th day and there was no difference in survival rate between day 7 and day 14. Cell proliferation test showed that the A value of the KLD-12 solutions was not significantly different from that of control groups （complete culture media） （P〉0.05） at the 24th and 48th h. The hemolysis rate of KLD-12 solution was 0.112%. Skin irritation test showed that the skin injected with KLD-12 solution remained normal and the score of skin irritation was 0. The histological examination with HE staining exhibited that the skin layers were clear and there was no infiltration with neutrophilic granulocytes and lymphocytes. It is concluded that KLD-12 peptide hydrogel bad a good biocompatibility with host rabbit and MSCs, and KLD-12 pep- tide hydrogel can provide an appropriate microenvironment for MSCs.

Bone Remodeling, Biomaterials And Technological Applications: Revisiting Basic Concepts

Presently, several different graft materials are employed in regenerative or corrective bone surgery. However current misconceptions about these biomaterials, their use and risks may compromise their correct application and development. To unveil these misconceptions, this work briefly reviewed concepts about bone remodeling, grafts classification and manufacturing processes, with a special focus on calcium phosphate materials as an example of a current employed biomaterial. Thus a search on the last decade was performed in Medline, LILACS, Scielo and other scientific electronic libraries using as keywords biomaterials, bone remodeling, regeneration, biocompatible materials, hydroxyapatite and therapeutic risks. Our search showed not only an accelerated biotechnological development that brought significant advances to biomaterials use on bone remodeling treatments but also several therapeutic risks that should not be ignored. The biomaterials specificity and limitations to clinical application point to the current need for developing safer products with better interactions with the biological microenvironments.

Surface Characterization and Tribology Behavior of PMMA Processed by Excimer Laser

Polyoxymethylene methacrylate (PMMA) is widely used in ophthalmic biomaterials. Misuse of PMMA in extreme environments is likely to damage the ocular surface and intraocular structures. The surface characterization and tribological behavior of PMMA processed using an excimer laser were investigated in this study by contrasting diferent lubrication conditions and friction cycles. The results show that the roughness of the material surface increases with laser processing, which changes its physical structure. Under lubrication, the laser-treated PMMA exhibits better hydrophilicity, especially during the use of eye drops. No obvious relationship exists between the laser-processing time and friction behavior. However, the laser treatment may contribute to the formation of friction and wear mechanisms of PMMA materials. Laser-treated PMMA in saline solution exhibits better abrasive resistance by showing a lower wear rate than that in eye drops, although it has a higher friction coefcient. In this study, the diferent friction stages in laser-treated PMMA were clarifed under two lubrication conditions. The wear rates of the laser-treated PMMA were found to decrease with the number of cycles, and the friction coefcient has a similar variation tendency. The wear behavior of the laser-treated PMMA is dominated by the main abrasive wear and secondary transferred flm formation. This study provides a theoretical basis for the development and application of ophthalmic biomaterials in complex environments by examining the material surface interface behavior and wear mechanism after laser processing using PMMA as the research matrix.

IMMOBILIZATION OF POTENTIALLY BIOACTIVE MOIETIES ONTO POLYETHER WITH POLY(ETHYLENE GLYCOL)-SULFONATE SPACER

A new reactive graft copolymer, poly(tetramethylene glycol)-graft-omega-propyl sodium sulfonate-poly(ethylene glycol) (PTMG-g-PEG-CH2CH2CH2SO3-Na+), was synthesized by the cationic polymerization of alpha-omega-bifunctional PEG macromonomer ((sic)CH2-PEG-CH2CH2CH2SO3Na) and THF. The obtained copolymer exhibits the expected structure as indicated by the result of characterization. Two amino acids (L-arginine, L-tyrosine) were covalently attached to the copolymer after converting the sulfonate group, to sulfonyl chloride. So the new reactive graft copolymer (PTMG-g-PEG-CH2CH2CH2SO3-Na+) is expected to be very useful in attachment of potentially bioactive moieties to polymer via a hydrophilic PEG spacer.

Comparative Dimensional and Microscopic Analysis of the Strength and Hardness of Internal Fixation Plates

The fixation stability achieved with the use of plates and screws in oral and maxillofacial surgery is a decisive factor in treatment success. The mechanical and structural properties of the internal fixation materials have direct influence on the dimensional stability and resistance of a fixation system, thus influencing treatment outcomes. This study proposed to analyze the dimensional and resistance patterns of titanium plates used for obtaining stable fixation in orthognathic surgery and craniofacial trauma. For this study, 30 conventional 2.0 mm straight four hole plates with bridge from three brands commercialized in Brazil, were subjected to macroscopic, microscopic, strength and hardness analysis. The dimensional measurements were performed using a digital caliper. Energy-dispersive X-ray spectroscopy analysis was performed by scanning electron microscopy to analyze the chemical composition of the samples. The mechanical resistance tests were performed with a universal testing machine. The samples were then submitted to Vickers hardness analysis, complying with the standards of ASTM E92. The data collected from the dimensional study was submitted to statistical analysis of the coefficient of variation, while the values obtained during the mechanical tests were analyzed by variance (ANOVA) and Tukey’s test (p < 0.05). The sample groups presented different performances in resistance, hardness, size and surface, even though they were reported to be chemically similar compounds that allowed us to conclude the plates from Group 2 were more resistant than groups 1 and 3.

Biocompatibility and degradation comparisons of four biodegradable copolymeric osteosynthesis systems used in maxillofacial surgery: A goat model with four years follow-up

pplying biodegradable osteosyntheses avoids the disadvantages of titanium osteosyntheses. However, foreign-body reactions remain a major concern and evidence of complete resorption is lacking. This study compared the physico-chemical properties, histological response and radiographs of four copolymeric biodegradable osteo-synthesis systems in a goat model with 48-months follow-up. The systems were implanted subperiosteally in both tibia and radius of 12 Dutch White goats. The BioSorb FX [poly(70LLA-co-30DLLA)], Inion CPS [poly([70–78.5] LLA-co-[16–24]DLLA-co-4TMC)], SonicWeld Rx [poly(DLLA)], LactoSorb [poly(82LLA-co-18GA)] systems and a negative control were randomly implanted in each extremity. Samples were assessed at 6-, 12-, 18-, 24-, 36-, and 48-month follow-up. Surface topography was performed using scanning electron microscopy (SEM). Differential scanning calorimetry and gel permeation chromatography were performed on initial and explanted samples. Histological sections were systematically assessed by two blinded researchers using (polarized) light microscopy, SEM and energy-dispersive X-ray analysis. The SonicWeld Rx system was amorphous while the others were semi-crystalline. Foreign-body reactions were not observed during the complete follow-up. The SonicWeld Rx and LactoSorb systems reached bone percentages of negative controls after 18 months while the BioSorb Fx and Inion CPS systems reached these levels after 36 months. The SonicWeld Rx system showed the most predictable degradation profile. All the biodegradable systems were safe to use and well-tolerated (i.e., complete implant replacement by bone, no clinical or histological foreign body reactions, no [sterile] abscess formation, no re-interventions needed), but nanoscale residual polymeric fragments were observed at every system’s assessment.

Rationalizing the Development of Biomaterials with A New Way of Thinking

The history of biomaterials research is seriously surveyed. It is found that an immutable way of thinking for developing biomaterials is rooted deeply in Western medicine and biology. It is necessary to modify or change the current status of thinking. In this paper, the author presents an idea to research and develop biomaterials via a combined way of thinking, i.e., combining together the wisdom and knowledge of Western medicine, Chinese medicine, and other disciplines.

听骨赝复物

随着耳显微外科的迅速发展，鼓室成形术逐渐推广，对听骨链重建材料的研究也逐步深入，现就国内外对听骨链重建材料的研究现状进行综述。

Progress in various crosslinking modification for acellular matrix

Objective To review the current crosslinking strategies for acelluar matrix scaffold,laying the foundation for subsequent experiment.Data sources Data were mainly obtained from recent papers published in PubMed or indexed by Web of Science,with keyword like crosslinking.Results Various crosslinking strategies,including chemical,physical and biological methods,have been introduced to facilitate the performance of fresh acellular matrix.Chemical crosslinking reagents,involved in synthetic and naturally derived agents,need to be eliminated before implantation in case of their potential biotoxicity,although several crosslinking agents with less toxicity and specific characteristics have been developed.Physical crosslinking methods present to be safe,additive-free and relatively controllable for rapid surface functionalization with no consideration of remaining radioactivity.Biological crosslinking strategies have attracted great interest,and have been demonstrated to enhance collagen-based crosslinking since their preparations do not need toxic or potentially biologically contaminated substances and can be carried out under physiological conditions.Conclusions Kinds of crosslinking methods with its potential advantages have been developed to modify raw acelluar matrix,of which the performance are promising after being crosslinked by several crosslinking treatments.Further preclinical and clinical evaluations should be taken to vertify their safety and efficacy for the tissues and organs substitutes in tissue and regenerative medicine.