Physicochemical properties of a novel chiral self-assembling peptide R-LIFE-1 and its controlled release to exosomes / 生物医学工程学杂志

This research aims to investigate the encapsulation and controlled release effect of the newly developed self-assembling peptide R-LIFE-1 on exosomes. The gelling ability and morphological structure of the chiral self-assembling peptide (CSAP) hydrogel were examined using advanced imaging techniques, including atomic force microscopy, transmission electron microscopy, and cryo-scanning electron microscopy. The biocompatibility of the CSAP hydrogel was assessed through optical microscopy and fluorescent staining. Exosomes were isolated via ultrafiltration, and their quality was evaluated using Western blot analysis, nanoparticle tracking analysis, and transmission electron microscopy. The controlled release effect of the CSAP hydrogel on exosomes was quantitatively analyzed using laser confocal microscopy and a BCA assay kit. The results revealed that the self-assembling peptide R-LIFE-1 exhibited spontaneous assembly in the presence of various ions, leading to the formation of nanofibers. These nanofibers were cross-linked, giving rise to a robust nanofiber network structure, which further underwent cross-linking to generate a laminated membrane structure. The nanofibers possessed a large surface area, allowing them to encapsulate a substantial number of water molecules, thereby forming a hydrogel material with high water content. This hydrogel served as a stable spatial scaffold and loading matrix for the three-dimensional culture of cells, as well as the encapsulation and controlled release of exosomes. Importantly, R-LIFE-1 demonstrated excellent biocompatibility, preserving the growth of cells and the biological activity of exosomes. It rapidly formed a three-dimensional network scaffold, enabling the stable loading of cells and exosomes, while exhibiting favorable biocompatibility and reduced cytotoxicity. In conclusion, the findings of this study support the notion that R-LIFE-1 holds significant promise as an ideal tissue engineering material for tissue repair applications.

Effect of preconditioning the fractured coronal fragments with remineralizing agents on fracture resistance of re-attached teeth

Background: Fragment re-attachment has been considered as one of the treatment modalities for the management of fractured anterior teeth. Hydration of fractured fragments aids in inhibiting the loss of ions and maintains vitality and esthetics. Aim: The study aimed to evaluate the effect of preconditioning the fractured fragments with remineralizing agents on fracture resistance of re-attached teeth. Settings and Design: This was an in vitro study. Materials and Methods: Sixty freshly extracted noncarious human permanent maxillary central and lateral incisors were randomly allocated into three Groups of 20 each: Group 1: 2% sodium fluoride (2%NaF), Group 2: casein phosphopeptide–amorphous calcium phosphate (CPP-ACP), and Group 3: self-assembling peptide P11-4 (SAP). These were further divided into two subgroups of 10 teeth each, based on contact time with remineralizing agents, i.e., 30 min and 2 h. Fractured fragments were treated with remineralizing agents for a specified contact time and then re-attached with flowable composite resin. Force required to fracture the re-attached tooth was recorded in Newtons using universal testing machine. Statistical Analysis: Unpaired t-test, one-way analysis of variance test, and post hoc Tukey test were used for the statistical analysis. Results: A higher fracture resistance was noticed in fragments treated with 2% NaF (30 min- 215.6 N, 2 h- 188.5 N) compared to CPP-ACP (30 min- 141.3 N, 2 h- 111.1 N) and SAP (30 min- 134.8 N, 2 h- 149.5 N). At 30 min interval, it was found to be more in 2% NaF and CPP-ACP groups compared to 2 h. However, it increased with time in the SAP group. A statistically significant difference was found between the groups at both time intervals (P = 0.007 and 0.017). Conclusion: Preconditioning of fractured coronal fragments with 2% NaF showed higher fracture resistance compared to CPP-ACP and self-assembling peptide P11-4. Samples treated with SAP P11-4 exhibited good fracture resistance at 2 h contact time.

Scaffolds for dental pulp regeneration and revascularization / 中国组织工程研究

BACKGROUND: Rapid development in tissue engineering research and technology makes dental pulp regeneration and revascularization possible. The interactions of stem cells, scaffolds and signaling factors in tissue engineering are particularly important. Whether stem cells can proliferate, differentiate and develop dental pulp-like tissue greatly depends on the choice of scaffolds OBJECTIVE: To review the widely studied and effective scaffold materials and two methods of scaffold preparation and analyze their applications in dental pulp reconstruction and their revascularization ability. METHODS: The first author searched PubMed, Wanfang and CNKI databases using a computer for relevant articles published between January 1, 2019 and September 30, 2019 with the search terms “pulp regeneration, pulp revascularization, scaffold” in English, and “pulp regeneration, pulp revascularization, revascularization, scaffold” in Chinese. A total of 421 English articles and 181 Chinese articles were retrieved. Finally, 61 articles were reviewed. RESULTS AND CONCLUSION: Platelet-derived scaffolds, extracellular-matrix-derived scaffolds, and self-assembling peptide take effect in pulp regeneration and revascularization. Composite materials combining natural and synthetic materials prepared by hydrogel and nanomaterial techniques exhibited advantages in cell proliferation, differentiation, migration, adherence, anti-inflammation, and factor delivery. The modified composite materials have a strong ability to promote vascularization. With the development of scaffold design and preparation technology based on hydrogels and nanomaterials, problems regarding insufficient scaffold source and unstable clinical effect will be solved in the future.

Chirality Self-assembling peptide for rats endometrial regeneration model / 生物工程学报

Here we investigate the physical and chemical properties of chiral self-assembling peptides and the role of uterine trauma regeneration. The circular dichroism was used to analyze secondary structure of chiral self-assembled peptide, and Congo red staining was used to observe the macroscopic process of peptide self-assembling. Erythrocyte lysis assay was used to examine the cleavage of peptide on cell membrane. The nanofiber scaffolds self-assembled by Chiral self-assembling peptides were used as the three-dimensional culture material to observe the growth effect of Hela cell. CCK-8 (cell counting kit-8) was used to study cell viability level between 2D (2-dimensional) and 3D (3-dimensional) culture environment. Rats endometrium curettage model was founded to evaluate the changes by immunohistochemistry staining and and HE staining. The secondary structure of chiral self-assembling peptides was stable β-sheet, and peptide could form dense membrane structure after 24 hours self-assembling cultured in salt ions. There was no harmful for the cell membrane of the peptide before and after self-assembling. Animal experiments show that chiral self-assembling peptide can significantly reduce the inflammatory response, promote the production of neovascularization, and accelerate the repair process. Chiral self-assembling peptide, as a new type of scaffold material, can construct a three-dimensional cell culture environment and used to repair uterine trauma.

The experimental study on repair of rat femoral condyle defect with peripheral blood mesenchymal stem cells combined with absorbable gelatin sponge-self assembling peptide / 实用医学杂志

Objective This study aimed to explore the effect of peripheral blood mesenchymal stem cells combined with porous absorbable gelatin sponge/self assembling peptide composite scaffolds on SD rat femoral con-dyle bone defect reconstruction and provide a new strategy for the repair of bone defects. Methods 30 female SD rats,8W age,were randomly divided into 3 groups,10 every group.The group A was blank control group,group B was porous absorbable gelatin sponge/self assembling peptide composite scaffold group,and group C was periph-eral blood mesenchymal stem cells combined with porous absorbable gelatin sponge/self assembling peptide compos-ite scaffold group. The effect of osteogenesis was observed by paraffin section,hematoxylin eosin staining,X-ray examination,and Micro-CT scanning in 3 dimensional reconstruction of femoral condyle defect. Results Imaging examination showed that the experimental group had better osteogenesis effect. Histological examination showed that a lot of new bone tissue was found in group C,while only a small amount of new bone was found in the group of A and B. Conclusions The experiment shows that peripheral blood mesenchymal stem cells as the seed cells for tissue engineering,combined with porous absorbable gelatin sponge-self assembling peptide has better ability to repair bone defects,and has good application prospect,which is worthy of further research.

Primary Study on Constructing Anti-cancer Drug in-situ Hydrogel by Self-assembling Peptide RAD16-Ⅰ / 中国药房

OBJECTIVE:To investigate the possibility of constructing anti-cancer drug in-situ hydrogel with self-assembling peptide RAD16-Ⅰ. METHODS:The rheological parameters as storage modulus(G′),loss modulus(G″)and phase angle(Δ)of 0.1%,0.2% and 0.5% RAD16-Ⅰ solution containing paclitaxel or not were determined by rheometer before and after mixing with isometric phosphate buffer solution (PBS);RAD16-Ⅰ solution containing paclitaxel or not were mixed with breast cancer MDA-MB-435S cells culture medium to obtain hydrogel,the status and effect of which on cell morphology were observed by in-verted microscope (compared with paclitaxel solution). RESULTS:In RAD16-Ⅰ solution containing paclitaxel or not,G′was close to or slightly higher than G″,and G′and G″had changed slightly as the concentration of peptide increased. Compared with not mixed with PBS,G′increased significantly in concentration-dependent manner after mixed with PBS,and G″also increased but was slighter than G′;Δ decreased significantly. In cell culture media,RAD16-Ⅰ solutions containing paclitaxel could form hy-drogel and maintain their gel form,cancer cells kept same morphology after treated with hydrogel and same concentration of pacli-taxel solution for same time. CONCLUSIONS:RAD16-Ⅰ solutions containing paclitaxel can form hydrogel under simulated physi-ological conditions,which can maintain their gel form and have anti-cancer effect of paclitaxel.

Structural characteristics and advantages of a self-assembling peptide nanofiber scaffold / 中国组织工程研究

BACKGROUND:Three-dimensional self-assembling peptide nanofiber hydrogel scaffold can simulate the in vivo microenvironment and provide a structural model for cells, which promotes the right composition of extracel ular matrix and cel growth, as wel as improves the cel functions. OBJECTIVE:To review the fundamental research and the experimental study of the self-assembling peptide nanofiber scaffold in the nerve tissue engineering. METHODS:Literatures concerning basic and experimental studies on the self-assembling peptide nanofiber scaffold in the nerve tissue engineering were reviewed via searching PubMed and VIP databases (2000/2013) using the key words of“self-assembling peptide, nanofiber scaffold, RADA16, nerve tissue engineering, neural stem cel . RESULTS AND CONCLUSION:Self-assembling peptide nanofiber scaffold is a novel and ideal tissue engineering material which provides new method for nerve injury repairing, for it not only solves the problem of poor compatibility between the material and cells, but also plays a much more pivotal role in maintaining three-dimensional properties, promoting cel activities and mimicking the extracel ular matrix, which is superior to other materials. However, there stil exist some chal enges in the area of self-assembling peptides, including short-term issues such as integrating of self-assembling peptide with bio-macromolecular material or relatively developed traditional transplant;and long-term issues such as adapting immune system in vivo, treating targets within cells and anticipating the future fate of highly integrated scaffolds.

Advance on the nerve tissue engineering scaffolds of self-assembling peptide / 国际生物医学工程杂志

The nerve tissue engineering is to apply scalfolds and seed cells for the treatment of injury or disease of nerve system by restoring their anatomic structures and funetiorm.The scaffolds played important roles in supporting and conducting axonal regeneration.They could also limit the in-growth of scar tissue and hence help to build the connection between axonal and target cell.Self-assembling peptide scaffold is one of the excellent material used is nerve tissue engineering.This article reviews the self-assembling peptide based scaffolds for nerve tissue engineering and discusses the unsolved problems in the fields and the trend d the related research in the future.

Study on Self-Assembling Peptide In-Situ Gel as Potential Protein Carrier / 中国药房

OBJECTIVE: To investigate the feasibility of introducing self-assembling peptides as protein drug carrier.METHODS: By using RAD16-Ⅰ as a model of self-assembling peptides,lysozyme as the model of protein drug,the property of self-assembling peptide solution containing protein to form hydrogel in-situ were characterized by rheology,and the property of protein release in vitro from self-assembling peptide in-situ hydrogel was studied.RESULTS: The self-assembling peptide RAD16-Ⅰ can form hydrogel with certain mechanical intensity rapidly after its solution contained protein being mixed with PBS.Proteins can release easily from RAD16-Ⅰ hydrogel in a sustained-release manner to some extent.About 80% of proteins can be released from the hydrogel within 8 hours and the cumulative protein release from 1.5% hydrogel was less than 90%.The bio-activity of lysozyme released from RAD16-Ⅰ hydrogel was well preserved as 98% to 115%.CONCLUSION: Self-assembling peptide can be employed as potential in-situ hydrogel carrier for protein drugs.