Biomimetic Biomaterials Research Articles

Innovative Bioactive Ca-SZ Coating on Titanium Dental Implants: A Multidimensional Structural and Elemental Analysis.

The design of new, biomimetic biomaterials is of great strategic interest and is converging for many applications, including in implantology. This study explores a novel approach to improving dental implants. Although endosseous TA6V alloy dental implants are widely used in oral implantology, this material presents significant challenges, notably the prevalence of peri-implantitis. Therefore, in this study, we investigate a new advance in the design of hybrid medical devices. This involves the design of a Ca-SZ coating deposited by PVD on a TA6V substrate. This approach aims to overcome the inherent limitations of each of these materials, namely TA6V's susceptibility to peri-implantitis on the one hand and zirconia's excessively high Young's modulus compared with bone on the other, while benefiting from their respective advantages, such as the ductility of TA6V and the excellent biocompatibility of zirconia, offering relevant prospects for the design of high-performance implantable medical devices. This study integrates characterisation techniques, focusing on the structural and elemental analysis of the Ca-SZ coating by XRD and TEM. The results suggest that this coating combines a tetragonal structure, a uniform morphology with no apparent defects, a clean interface highlighting good adhesion, and a homogeneous composition of calcium, predisposing it to optimal biocompatibility. All of these findings make this innovative coating a particularly suitable candidate for application in dental implantology.

Biomimetic Hydrogels as the Inductive Endochondral Ossification Template for Promoting Bone Regeneration.

Repairing critical size bone defects (CSBD) is a major clinical challenge and requires effective intervention by biomaterial scaffolds. Inspired by the fact that the cartilaginous template-based endochondral ossification (ECO) process is crucial to bone healing and development, developing biomimetic biomaterials to promote ECO is recognized as a promising approach for repairing CSBD. With the unique highly hydrated 3D polymeric network, hydrogels can be designed to closely emulate the physiochemical properties of cartilage matrix to facilitate ECO. In this review, the various preparation methods of hydrogels possessing the specific physiochemical properties required for promoting ECO are introduced. The materiobiological impacts of the physicochemical properties of hydrogels, such as mechanical properties, topographical structures and chemical compositions on ECO, and the associated molecular mechanisms related to the BMP, Wnt, TGF-β, HIF-1α, FGF, and RhoA signaling pathways are further summarized. This review provides a detailed coverage on the materiobiological insights required for the design and preparation of hydrogel-based biomaterials to facilitate bone regeneration.

Dental-derived stem cells in tissue engineering: the role of biomaterials and host response.

Dental-derived stem cells (DSCs) are attractive cell sources due to their easy access, superior growth capacity and low immunogenicity. They can respond to multiple extracellular matrix signals, which provide biophysical and biochemical cues to regulate the fate of residing cells. However, the direct transplantation of DSCs suffers from poor proliferation and differentiation toward functional cells and low survival rates due to local inflammation. Recently, elegant advances in the design of novel biomaterials have been made to give promise to the use of biomimetic biomaterials to regulate various cell behaviors, including proliferation, differentiation and migration. Biomaterials could be tailored with multiple functionalities, e.g., stimuli-responsiveness. There is an emerging need to summarize recent advances in engineered biomaterials-mediated delivery and therapy of DSCs and their potential applications. Herein, we outlined the design of biomaterials for supporting DSCs and the host response to the transplantation.

Bioactive Materials for Bone Regeneration: Biomolecules and Delivery Systems.

Novel tissue regeneration strategies are constantly being developed worldwide. Research on bone regeneration is noteworthy, as many promising new approaches have been documented with novel strategies currently under investigation. Innovative biomaterials that allow the coordinated and well-controlled repair of bone fractures and bone loss are being designed to reduce the need for autologous or allogeneic bone grafts eventually. The current engineering technologies permit the construction of synthetic, complex, biomimetic biomaterials with properties nearly as good as those of natural bone with good biocompatibility. To ensure that all these requirements meet, bioactive molecules are coupled to structural scaffolding constituents to form a final product with the desired physical, chemical, and biological properties. Bioactive molecules that have been used to promote bone regeneration include protein growth factors, peptides, amino acids, hormones, lipids, and flavonoids. Various strategies have been adapted to investigate the coupling of bioactive molecules with scaffolding materials to sustain activity and allow controlled release. The current manuscript is a thorough survey of the strategies that have been exploited for the delivery of biomolecules for bone regeneration purposes, from choosing the bioactive molecule to selecting the optimal strategy to synthesize the scaffold and assessing the advantages and disadvantages of various delivery strategies.

Research progress of biomaterials and innovative technologies in urinary tissue engineering.

Substantial interests have been attracted to multiple bioactive and biomimetic biomaterials in recent decades because of their ability in presenting a structural and functional reconstruction of urinary tissues. Some innovative technologies have also been surging in urinary tissue engineering and urological regeneration by providing insights into the physiological behavior of the urinary system. As such, the hierarchical structure and tissue function of the bladder, urethra, and ureter can be reproduced similarly to the native urinary tissues. This review aims to summarize recent advances in functional biomaterials and biomimetic technologies toward urological reconstruction. Various nanofirous biomaterials derived from decellularized natural tissues, synthetic biopolymers, and hybrid scaffolds were developed with desired microstructure, surface chemistry, and mechanical properties. Some growth factors, drugs, as well as inorganic nanomaterials were also utilized to enhance the biological activity and functionality of scaffolds. Notably, it is emphasized that advanced approaches, such as 3D (bio) printing and organoids, have also been developed to facilitate structural and functional regeneration of the urological system. So in this review, we discussed the fabrication strategies, physiochemical properties, and biofunctional modification of regenerative biomaterials and their potential clinical application of fast-evolving technologies. In addition, future prospective and commercial products are further proposed and discussed.

Clinical evaluation of the perception of post-trauma paresthesia in the mandible, using a biomimetic material: A preliminary study in humans

There is a great effort from numerous research groups in the development of materials and therapeutic strategies for the functional recovery of patients who have suffered peripheral nerve injuries (PNI). In an article in vivo, the formation of a nerve bridge was observed, reconnecting the distal and proximal stumps, in the sciatic nerve of rats, indicating the effective participation of the biomaterial in the recovery of peripheral nerve injuries. For the current pilot study, 15 cases of multiple fractures of the mandible, with involvement of the inferior alveolar nerve (IAN) were selected and studied: JC (control cases) n = 6 with conventional treatment, and JT (treated cases) n = 9, with the use of biomimetic biomaterial. The evaluation of the return to sensitivity was measured through a self-assessment, where the patients assigned scores from 0 to 10, where zero (0) represented the complete absence of sensitivity and ten (10) the normality of the perception of local sensitivity. Patients were evaluated from the preoperative period to the 360th day. The statistical results obtained by the t-Student, Shapiro-Wilk normality and non-parametric One-Way ANOVA tests indicated statistically significant differences (p < 0.005; 0.005 e 0.5 respectively), between the two treatments, which were reflected in the clinical results observed, we also calculate the size of the effect represented by ϵ2, calculated by Cohen's d. The results indicate a great difference between the treatments performed,ϵ2 = 1.00. In the 6 cases followed up in the JC group, four remained with a significant deficit until the end of the evaluations and two indicated the remission of the lack of sensitivity in this period. In the JT group, in 28 days, all cases indicated complete remission of the lack of sensitivity with healing concentration. In one of the cases where there was a complete rupture of the mental nerve, the (score-10) was observed in 60 days. The observed results indicate the existence of a statistical significance between the groups and an important relationship when using the biomimetic biomaterial during the recovery of the perception of sensitivity in polytraumatized patients, compatible with the results observed in laboratory animals, which may indicate its clinical feasibility in the reduction of sequelae in PNI.

Human Mesenchymal Stem Cells and Innovative Scaffolds for Bone Tissue Engineering Applications.

Stem cell-based therapy is a significant topic in regenerative medicine, with a predominant role being played by human mesenchymal stem cells (hMSCs). The hMSCs have been shown to be suitable in regenerative medicine for the treatment of bone tissue. In the last few years, the average lifespan of our population has gradually increased. The need of biocompatible materials, which exhibit high performances, such as efficiency in bone regeneration, has been highlighted by aging. Current studies emphasize the benefit of using biomimetic biomaterials, also known as scaffolds, for bone grafts to speed up bone repair at the fracture site. For the healing of injured bone and bone regeneration, regenerative medicine techniques utilizing a combination of these biomaterials, together with cells and bioactive substances, have drawn a great interest. Cell therapy, based on the use of hMSCs, alongside materials for the healing of damaged bone, has obtained promising results. In this work, several aspects of cell biology, tissue engineering, and biomaterials applied to bone healing/regrowth will be considered. In addition, the role of hMSCs in these fields and recent progress in clinical applications are discussed. Impact Statement The restoration of large bone defects is both a challenging clinical issue and a socioeconomic problem on a global scale. Different therapeutic approaches have been proposed for human mesenchymal stem cells (hMSCs), considering their paracrine effect and potential differentiation into osteoblasts. However, different limitations are still to be overcome in using hMSCs as a therapeutic opportunity in bone fracture repair, including hMSC administration methods. To identify a suitable hMSC delivery system, new strategies have been proposed using innovative biomaterials. This review provides an update of the literature on hMSC/scaffold clinical applications for the management of bone fractures.

Bioprinted cancer-stromal in-vitro models in a decellularized ECM-based bioink exhibit progressive remodeling and maturation

Constant matrix remodeling and cellular heterogeneity in cancer are key contributors to its development and can profoundly alter treatment efficacy. Developing in-vitro models containing relevant features that can recapitulate these aspects of the tumor microenvironment and that are well characterized can circumvent the limitations of conventional 2D cultures and animal models. Automated fabrication methods combined with biomimetic biomaterials have provided the opportunity to create platforms that can potentially incorporate a heterogeneous population of cells in a 3D environment that allows cell–cell and cell-ECM interactions with reproducibility. This study used 3D extrusion bioprinting and a composite bioink containing a reinforced decellularized extracellular matrix (ECM) hydrogel to fabricate a head and neck cancer in-vitro model. The constituents of this model included fibroblasts and active ECM proteins to represent the stroma, along with HNSCC cells to represent the tumor component. The topographical characterization of the bioink showed a fibrous network with nanometer-sized pores. After cell encapsulation and model fabrication, we observed spheroid development and growth over time with cancer cells in the core and fibroblasts in the periphery. Our model is compatible with matrix metalloproteinase (MMP) quantification techniques and showed significant differences in the presence of MMP-9 and MMP-10 compared to the control groups. This characterized model is proposed as a tool for further translational and drug discovery applications since it provides a biomimetic scenario that allows the study of the tumor microenvironment in-vitro using nondestructive longitudinal monitoring over time.

Vascularization of a Bone Organoid Using Dental Pulp Stem Cells.

Bone organoids offer a novel path for the reconstruction and repair of bone defects. We previously fabricated scaffold-free bone organoids using cell constructs comprising only bone marrow-derived mesenchymal stem cells (BMSCs). However, the cells in the millimetre-scale constructs were likely to undergo necrosis because of difficult oxygen diffusion and nutrient delivery. Dental pulp stem cells (DPSCs) are capable of differentiating into vascular endothelial lineages and have great vasculogenic potential under endothelial induction. Therefore, we hypothesized that DPSCs can serve as a vascular source to improve the survival of the BMSCs within the bone organoid. In this study, the DPSCs had greater sprouting ability, and the proangiogenic marker expressions were significantly greater than those of BMSCs. DPSCs were incorporated into the BMSC constructs at various ratios (5%-20%), and their internal structures and vasculogenic and osteogenic characteristics were investigated after endothelial differentiation. As a result, the DPSCs are differentiated into the CD31-positive endothelial lineage in the cell constructs. The incorporation of DPSCs significantly suppressed cell necrosis and improved the viability of the cell constructs. In addition, lumen-like structures were visualized by fluorescently labelled nanoparticles in the DPSC-incorporated cell constructs. The vascularized BMSC constructs were successfully fabricated using the vasculogenic ability of the DPSCs. Next, osteogenic induction was initiated in the vascularized BMSC/DPSC constructs. Compared with only BMSCs, constructs with DPSCs had increased mineralized deposition and a hollow structure. Overall, this study demonstrated that vascularized scaffold-free bone organoids were successfully fabricated by incorporating DPSCs into BMSC constructs, and the biomimetic biomaterial is promising for bone regenerative medicine and drug development.

Biomimicry and 3D-Printing of Mussel Adhesive Proteins for Regeneration of the Periodontium-A Review.

Innovation in the healthcare profession to solve complex human problems has always been emulated and based on solutions proven by nature. The conception of different biomimetic materials has allowed for extensive research that spans several fields, including biomechanics, material sciences, and microbiology. Due to the atypical characteristics of these biomaterials, dentistry can benefit from these applications in tissue engineering, regeneration, and replacement. This review highlights an overview of the application of different biomimetic biomaterials in dentistry and discusses the key biomaterials (hydroxyapatite, collagen, polymers) and biomimetic approaches (3D scaffolds, guided bone and tissue regeneration, bioadhesive gels) that have been researched to treat periodontal and peri-implant diseases in both natural dentition and dental implants. Following this, we focus on the recent novel application of mussel adhesive proteins (MAPs) and their appealing adhesive properties, in addition to their key chemical and structural properties that relate to the engineering, regeneration, and replacement of important anatomical structures in the periodontium, such as the periodontal ligament (PDL). We also outline the potential challenges in employing MAPs as a biomimetic biomaterial in dentistry based on the current evidence in the literature. This provides insight into the possible increased functional longevity of natural dentition that can be translated to implant dentistry in the near future. These strategies, paired with 3D printing and its clinical application in natural dentition and implant dentistry, develop the potential of a biomimetic approach to overcoming clinical problems in dentistry.

3D-Printed Flat-Bone-Mimetic Bioceramic Scaffolds for Cranial Restoration.

The limitations of autologous bone grafts necessitate the development of advanced biomimetic biomaterials for efficient cranial defect restoration. The cranial bones are typical flat bones with sandwich structures, consisting of a diploe in the middle region and 2 outer compact tables. In this study, we originally developed 2 types of flat-bone-mimetic β-tricalcium phosphate bioceramic scaffolds (Gyr-Comp and Gyr-Tub) by high-precision vat-photopolymerization-based 3-dimensional printing. Both scaffolds had 2 outer layers and an inner layer with gyroid pores mimicking the diploe structure. The outer layers of Gyr-Comp scaffolds simulated the low porosity of outer tables, while those of Gyr-Tub scaffolds mimicked the tubular pore structure in the tables of flat bones. The Gyr-Comp and Gyr-Tub scaffolds possessed higher compressive strength and noticeably promoted invitro cell proliferation, osteogenic differentiation, and angiogenic activities compared with conventional scaffolds with cross-hatch structures. After implantation into rabbit cranial defects for 12 weeks, Gyr-Tub achieved the best repairing effects by accelerating the generation of bone tissues and blood vessels. This work provides an advanced strategy to prepare biomimetic biomaterials that fit the structural and functional needs of efficacious bone regeneration.

Nanostructured graphene oxide enriched with metallic nanoparticles as a biointerface to enhance cell adhesion through mechanosensory modifications.

Nanostructuring is a process involving surface manipulation at the nanometric level, which improves the mechanical and biological properties of biomaterials. Specifically, it affects the mechanotransductive perception of the microenvironment of cells. Mechanical force conversion into an electrical or chemical signal contributes to the induction of a specific cellular response. The relationship between the cells and growth surface induces a biointerface-modifying cytophysiology and consequently a therapeutic effect. In this study, we present the fabrication of graphene oxide (GO)-based nanofilms decorated with metallic nanoparticles (NPs) as potential coatings for biomaterials. Our investigation showed the effect of decorating GO with metallic NPs for the modification of the physicochemical properties of nanostructures in the form of nanoflakes and nanofilms. A comprehensive biocompatibility screening panel revealed no disturbance in the metabolic activity of human fibroblasts (HFFF2) and bone marrow stroma cells (HS-5) cultivated on the GO nanofilms decorated with gold and copper NPs, whereas a significant cytotoxic effect of the GO nanocomplex decorated with silver NPs was demonstrated. The GO nanofilm decorated with gold NPs beneficially managed early cell adhesion as a result of the transient upregulation of α1β5 integrin expression, acceleration of cellspreading, and formation of elongated filopodia. Additionally, the cells, sensing the substrate derived from the nanocomplex enriched with gold NPs, showed reduced elasticity and altered levels of vimentin expression. In the future, GO nanocomplexes decorated with gold NPs can be incorporated in the structure of architecturally designed biomimetic biomaterials as biocompatible nanostructuring agents with proadhesive properties.

Computational Biomaterials: Computational Simulations for Biomedicine.

With the flourishing development of material simulation methods (quantum chemistry methods, molecular dynamics, Monte Carlo, phase field, etc.), extensive adoption of computing technologies (high-throughput, artificial intelligence, machine learning, etc.), and the invention of high-performance computing equipment, computational simulation tools have sparked the fundamental mechanism-level explorations to predict the diverse physicochemical properties and biological effects of biomaterials and investigate their enormous application potential for disease prevention, diagnostics, and therapeutics. Herein, the term "computational biomaterials" is proposed and the computational methods currently used to explore the inherent properties of biomaterials, such as optical, magnetic, electronic, and acoustic properties, and the elucidation of corresponding biological behaviors/effects in the biomedical field are summarized/discussed. The theoretical calculation of the physiochemical properties/biological performance of biomaterials applied in disease diagnosis, drug delivery, disease therapeutics, and specific paradigms such as biomimetic biomaterials is discussed. Additionally, the biosafety evaluation applications of theoretical simulations of biomaterials are presented. Finally, the challenges and future prospects of such computational simulations for biomaterials development are clarified. It is anticipated that these simulations would offer various methodologies for facilitating the development and future clinical translations/utilization of versatile biomaterials.

Establishing a Diaphyseal Femur Fracture Model in Mice.

Bones have a significant regenerative capacity. However, fracture healing is a complex process, and depending on the severity of the lesions and the age and overall health status of the patient, failures can occur, leading to delayed union or nonunion. Due to the increasing number of fractures resulting from high-energy trauma and aging, the development of innovative therapeutic strategies to improve bone repair based on the combination of skeletal/mesenchymal stem/stromal cells and biomimetic biomaterials is urgently needed. To this end, the use of reliable animal models is fundamental to better understanding the key cellular and molecular mechanisms that determine the healing outcomes. Of all the models, the mouse is the preferred research model because it offers a wide variety of transgenic strains and reagents for experimental analysis. However, the establishment of fractures in mice may be technically challenging due to their small size. Therefore, this article aims to demonstrate the procedures for the surgical establishment of a diaphyseal femur fracture in mice, which is stabilized with an intramedullary wire and resembles the most common bone repair process, through cartilaginous callus formation.

3D printing of conch-like scaffolds for guiding cell migration and directional bone growth.

Regeneration of severe bone defects remains an enormous challenge in clinic. Developing regenerative scaffolds to directionally guide bone growth is a potential strategy to overcome this hurdle. Conch, an interesting creature widely spreading in ocean, has tough spiral shell that can continuously grow along the spiral direction. Herein, inspired by the physiological features of conches, a conch-like (CL) scaffold based on β-TCP bioceramic material was successfully prepared for guiding directional bone growth via digital light processing (DLP)-based 3D printing. Benefiting from the spiral structure, the CL scaffolds significantly improved cell adhesion, proliferation and osteogenic differentiation in vitro compared to the conventional 3D scaffolds. Particularly, the spiral structure in the scaffolds could efficiently induce cells to migrate from the bottom to the top of the scaffolds, which was like “cells climbing stairs”. Furthermore, the capability of guiding directional bone growth for the CL scaffolds was demonstrated by a special half-embedded femoral defects model in rabbits. The new bone tissue could consecutively grow into the protruded part of the scaffolds along the spiral cavities. This work provides a promising strategy to construct biomimetic biomaterials for guiding directional bone tissue growth, which offers a new treatment concept for severe bone defects, and even limb regeneration.

Evolution of Biomaterials

There is a clear need for increasingly versatile and effective implantable biomaterials, and to train qualified personnel for research and development in the field of biomaterials design and manufacturing. In all these implantable biomaterials, science and technology are imposing new designs with combinations of new biomaterials, new coatings, and new design and manufacturing technologies (biomimetic biomaterials, functional biomaterials, nanotechnology, finite element modeling, additive manufacturing, 3D printing, tissue engineering, and drug delivery) that will revolutionize the field of implants in the short term. Biomaterials are part of biomedical engineering and bring together knowledge from the world of science, engineering, biology, and medicine, being a multidisciplinary field where borders have no place.

Biomimetic porous scaffolds containing decellularized small intestinal submucosa and Sr2+/Fe3+ co-doped hydroxyapatite accelerate angiogenesis/osteogenesis for bone regeneration

The design of bone scaffolds is predominately aimed to well reproduce the natural bony environment by imitating the architecture/composition of host bone. Such biomimetic biomaterials are gaining increasing attention and acknowledged quite promising for bone tissue engineering. Herein, novel biomimetic bone scaffolds containing decellularized small intestinal submucosa matrix (SIS-ECM) and Sr2+/Fe3+ co-doped hydroxyapatite (SrFeHA) are fabricated for the first time by the sophisticated self-assembled mineralization procedure, followed by cross-linking and lyophilization post-treatments. The results indicate the constructed SIS/SrFeHA scaffolds are characterized by highly porous structures, rough microsurface and improved mechanical strength, as well as efficient releasing of bioactive Sr2+/Fe3+ and ECM components. These favorable physico-chemical properties endow SIS/SrFeHA scaffolds with an architectural/componential biomimetic bony environment which appears to be highly beneficial for inducing angiogenesis/osteogenesis both in vitro and in vivo. In particular, the cellular functionality and bioactivity of endotheliocytes/osteoblasts are significantly enhanced by SIS/SrFeHA scaffolds, and the cranial defects model further verifies the potent ability of SIS/SrFeHA to accelerate in vivo vascularization and bone regeneration following implantation. In this view these results highlight the considerable angiogenesis/osteogenesis potential of biomimetic porous SIS/SrFeHA scaffolds for inducing bone regeneration and thus may afford a new promising alternative for bone tissue engineering.

Lumbar Intervertebral Disc Herniation: Annular Closure Devices and Key Design Requirements.

Lumbar disc herniation is one of the most common degenerative spinal conditions resulting in lower back pain and sciatica. Surgical treatment options include microdiscectomy, lumbar fusion, total disc replacement, and other minimally invasive approaches. At present, microdiscectomy procedures are the most used technique; however, the annulus fibrosus is left with a defect that without treatment may contribute to high reherniation rates and changes in the biomechanics of the lumbar spine. This paper aims to review current commercially available products that mechanically close the annulus including the AnchorKnot® suture-passing device and the Barricaid® annular closure device. Previous studies and reviews have focused mainly on a biomimetic biomaterials approach and have described some mechanical and biological requirements for an active annular repair/regeneration strategy but are still far away from clinical implementation. Therefore, in this paper we aim to create a design specification for a mechanical annular closure strategy by identifying the most important mechanical and biological design parameters, including consideration of material selection, preclinical testing requirements, and requirements for clinical implementation.

Biodegradable Cationic Polymer Blends for Fabrication of Enhanced Artificial Antigen Presenting Cells to Treat Melanoma

Biomimetic biomaterials are being actively explored in the context of cancer immunotherapy because of their ability to directly engage the immune system to generate antitumor responses. Unlike cellular therapies, biomaterial-based immunotherapies can be precisely engineered to exhibit defined characteristics including biodegradability, physical size, and tuned surface presentation of immunomodulatory signals. In particular, modulating the interface between the biomaterial surface and the target biological cell is key to enabling biological functions. Synthetic artificial antigen presenting cells (aAPCs) are promising as a cancer immunotherapy but are limited in clinical translation by the requirement of ex vivo cell manipulation and adoptive transfer of antigen-specific CD8+ T cells. To move toward acellular aAPC technology for in vivo use, we combine poly(lactic-co-glycolic acid) (PLGA) and cationic poly(beta-amino-ester) (PBAE) to form a biodegradable blend based on the hypothesis that therapeutic aAPCs fabricated from a cationic blend may have improved functions. PLGA/PBAE aAPCs demonstrate enhanced surface interactions with antigen-specific CD8+ T cells that increase T cell activation and expansion ex vivo, associated with significantly increased conjugation efficiency of T cell stimulatory signals to the aAPCs. Critically, these PLGA/PBAE aAPCs also expand antigen-specific cytotoxic CD8+ T cells in vivo without the need of adoptive transfer. Treatment with PLGA/PBAE aAPCs in combination with checkpoint therapy decreases tumor growth and extends survival in a B16-F10 melanoma mouse model. These results demonstrate the potential of PLGA/PBAE aAPCs as a biocompatible, directly injectable acellular therapy for cancer immunotherapy.

Influence of residual chirality on the conformation and enzymatic degradation of glycopolypeptide based biomaterials

Glycopolypeptides as analogs of glycoproteins or glycosaminoglycans represent attractive building blocks for the construction of biomimetic biomaterials. However, the effects of amino acid chirality on the conformation and enzymatic degradation of glycopolypeptides are often overlooked. Here, we synthesized and characterized a range of glycopolypeptides composed of galactosylated poly(γ-propargylglutamate)s containing L- and/or D-glutamate residues. Glycopolypeptides containing pure L-glutamate residues were predominantly α-helical, and the helicity increased over the degree of polymerization of the polypeptide backbones (24 to 44). The glycopolypeptide with pure D-glutamate residues adopted a mirrored α-helical conformation, whilst apparent random coil conformation was observed for the glycopolypeptide with equally mixed enantiomeric residues. The enzymatic degradation rates of the glycopolypeptides were markedly reduced following the introduction of D-glutamate residues into backbones. Galactoside pendants on these glycopolypeptides maintained their binding to peanut agglutinin. These structure-property relationships provide new insight for the design of biomimetic biomaterials containing glycopolypeptides.