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The marine environment is believed to be the greatest treasure trove regarding availability of bioactive molecules and secondary metabolites from marine organisms. These untapped potential natural resources in the form of naturally derived polysaccharides such as chitin, chitosan, alginate, fucoidan, carrageenan and chondroitin sulfate are proven to be versatile biomaterials. Their superior structure and variability in their composition along with the mechanical, physicochemical and biological properties made them potent biomaterials in the field of biomedicine as pharmacological and drug delivery agents, as well as in regenerative medicine. Nanoformulations and 3D-scaffold designs of these biocompatible materials enabled significant advances in the field of molecular delivery and tissue engineering. Further, physical and chemical modifications to these biomaterials enhanced the therapeutic and regenerative capacity of biomolecules and stem cells in therapy, which are mostly under clinical investigations, and some are in clinical use. In recent years, there has been a tremendous rise in the use of these marine biomaterials (chitosan, fucoidan, alginate, biosilica, bio-ceramics etc.) as a replacement for synthetic materials in bone regenerative medicine. This chapter discusses the basic potent bio-functional properties, structural compatibility as scaffold materials and their applications in the multidisciplinary fields of molecular and clinical research. The latest biomaterial advances in the field of dental medicine and surgery for implantation are also discussed.

Nanoparticles are used in the clinic to treat cancer, resolve mineral deficiencies, image tissues, and facilitate vaccination. As a modular technology, nanoparticles combine diagnostic agents or therapeutics (e.g., elements, small molecules, biologics), synthetic materials (e.g., polymers), and biological molecules (e.g., antibodies, peptides, lipids). Leveraging these parameters, nanoparticles can be designed and tuned to navigate biological microenvironments, negotiate biological barriers, and deliver therapeutics or diagnostic agents to specific cells and tissues in the body. Recently, with the Emergency Use Authorization of the COVID‐19 lipid nanoparticle vaccines, the advantages and potential of nanoparticles as a delivery vehicle have been displayed at the forefront of biotechnology. Here, we provide a 5‐year status update on our original “Nanoparticles in the Clinic” review (also a 2‐year update on our second “Nanoparticles in the Clinic” review) by discussing recent nanoparticle delivery system approvals, highlighting new clinical trials, and providing an update on the previously highlighted clinical trials.

Sponges, Neofibularia nolitangere, can regenerate spontaneously after being broken down into small pieces, and the regenerated structure maintains the original appearance and function. Synthetic materials with such capabilities are highly desired but hardly achieved. Presented here is a sponge-inspired self-regenerative powder from a double-network (DN) tough hydrogel. Hydrogels are regenerated from their powder form, by addition of water, with preservation of the original appearance and mechanical properties. The powder-hydrogel-powder cycle can be repeated multiple times with little loss in mechanical properties, analogous to the regeneration of sponges. These DN hydrogels can be conveniently stored and easily shaped upon regeneration. This work may have implications in the development of regenerative materials for coatings and adhesives.

Control of blood microflow is crucial for the prevention and therapy of blood disorders, such as cardiovascular diseases and their complications. Conventional control strategies generally implant exogenous synthetic materials into blood vessels as labeling markers or actuating sources, which are invasive and incompatible with biological systems. Here, a label‐free, noninvasive, and biocompatible device constructed from natural red blood cells (RBCs) for controlling blood microflow in vivo is reported. The RBCs, optically manipulated, arranged, and rotated using scanning optical tweezers, can function as an optofluidic switch for targeted switching, directional enrichment, dynamic redirecting, and rotary actuation of blood microflow inside zebrafish. The regulation precision of the switch is determined to be at the single‐cell level, and the response time is measured as ≈200 ms using a streamline tracking method. This in vivo optofluidic switch may provide a biofriendly device for exploring blood microenvironments in a noncontact and noninvasive manner., An optofluidic switch, constructed from natural red blood cells and manipulated by optical tweezers, is proposed to control blood microflow in vivo at the single‐cell level. The flow rate and direction of the blood are determined by controlling local blood pressure using the optofluidic switch, providing a biocompatible tool for exploring blood microenvironments in a noncontact and noninvasive manner.

OBJECTIVE Surgical simulators aimed at mimicking elements of rhinoplasty surgery, specifically those aimed at improving cartilage suturing, are not available. Here, we present a surgical simulator for spreader graft placement that uses cartilage rather than synthetic materials and gauge improvement using objective measures for suture placement accuracy, speed, and efficiency of hand motion. METHODS Twenty-two otolaryngologists in two groups (residents [10] and experts [12]) were instructed to secure the two spreader graft specimen into position with three mattress sutures on a nose model that used porcine septal cartilage as a proxy for the human counterpart. Hand motion was tracked using an electromagnetic position sensing device. The time required to complete the suture task, total hand displacement, cumulative number of hand motion direction changes, and accuracy of suture insertion were measured. These measurements were compared between the two cohort groups for construct validity. The subjects completed a survey to evaluate realism and value of the model. RESULTS The expert group had a lower mean time required to complete the task (P

Natural and synthetic materials have been developed to provide a three-dimensional (3-D) scaffold that mimics the extracellular matrix properties for tissue regeneration and reconstruction. On account of the excellent biological and mechanical properties, diverse decellularized tissue materials have been developed as natural scaffolds. Among them, decellularized adipose tissue (DAT) has generated great interest in recent years due to the extensiveness of the source and the eximious potential to enhance the regeneration and repair of damaged tissues. In this review, we compared the different physical, chemical, and biological treatment in recorded decellularization methods, and illustrated the similarities and differences in the characteristics of various aspects of DATs prepared by different methods, including macroscopic (macro) and microcosmic (micro) structure, cellular contents removal, DNA quantification, collagen, glycosaminoglycan (GAG) or growth factors retention, and mechanical properties. We also summarized the DAT application in the studies of tissue regeneration, wound healing, drug screening, and other diseases. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A:2562-2573, 2018.

Lignin is an important source of synthetic materials because of its abundance in nature, low cost, stable supply, and no competition to the human food supply. Lignin, a cross-linked phenolic polymer, contains a large number of aromatic groups that can be used as a substitute for petroleum-based aromatic fine chemicals. However, modification of lignin is necessary for its application in advanced materials due to its chemically inert nature and structural complexity. Polymeric modification of lignin via graft copolymerization represents an important avenue for modification because this method forms stable covalent bond linkages between lignin and synthetic functional polymers. In this review, we discuss recent synthetic strategies toward polymeric modification of lignin using graft copolymerization and the special properties and applications of the produced lignin copolymers. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3515–3528

Bioactive, synthetic materials represent next-generation composites for tissue regeneration. Design of contemporary materials attempts to recapitulate the complexities of native tissue; however, few successfully mimic the order in nature. Recently, graphene oxide (GO) has emerged as a scaffold due to its potential for bioactive functionalization and long-range order instilled by the self-assembly of graphene sheets. Chemical reduction of GO results in a more compatible material with enhanced properties but compromises the ability to functionalize the graphenic backbone. However, using Johnson–Claisen rearrangement chemistry, functionalization is achieved that is not liable to reduction. From reduced Claisen graphene, we polymerized short homopeptides from α-amino acid N-carboxyanhydride monomers of glutamate and lysine to result in functionalized graphenes (pGlu-rCG and pLys-rCG) that are cytocompatible, degradable, and bioactive. Exposure to NIH-3T3 fibroblasts and RAW 264.7 macrophages revealed that the materials are cytocompatible and do not alter important sub-cellular compartments. Powders were hot pressed to form mechanically stiff (E′: 41 and 49 MPa), strong (UCS: 480 and 140 MPa), and tough (UT: 2898 and 584 J m−3 × 104) three-dimensional constructs (pGlu-rCG and pLys-rCG, respectively). Overall, we report a robust chemistry and processing strategy for facile bioactive functionalization of compatible, reduced Claisen graphene for three-dimensional biomedical applications. © 2017 Society of Chemical Industry

Research at the biological-material interface often has translation in mind, with applications in medical implants, drug delivery, and regenerative medicine. While the clinical impact of this research is undeniable, a clearer picture of the in vivo behavior of materials is needed to address longstanding limitations in performance and function. Advances in chemical biology and biotechnology have propelled our understanding of how small molecules and biologics behave in living systems. Adapting these techniques to the study of synthetic materials, enabled by modern polymer chemistry, will bring molecular resolution to biological-material interactions and guide the development of next-generation biomaterials for therapeutic and diagnostic applications.

The global coronavirus disease 2019 (COVID‐19) pandemic has rapidly increased the demand for facemasks as a measure to reduce the rapid spread of the pathogen. Throughout the pandemic, some countries such as Italy had a monthly demand of ca. 90 million facemasks. Domestic mask manufacturers are capable of manufacturing 8 million masks each week, although the demand was 40 million per week during March 2020. This dramatic increase has contributed to a spike in the generation of facemask waste. Facemasks are often manufactured with synthetic materials that are non‐biodegradable, and their increased usage and improper disposal are raising environmental concerns. Consequently, there is a strong interest for developing biodegradable facemasks made with for example, renewable nanofibres. A range of natural polymer‐based nanofibres has been studied for their potential to be used in air filter applications. This review article examines potential natural polymer‐based nanofibres along with their filtration and antimicrobial capabilities for developing biodegradable facemask that will promote a cleaner production.

Recognition of oligosaccharides is associated with very limited specificity due to their strong solvation in water and the high degree of subtle structural variations between them. Here, oligosaccharide recognition sites are created on material surfaces with unmatched, binary on–off binding behavior, sharply discriminating a target oligosaccharide over closely related carbohydrate structures. The basis for the superselective binding behavior relies on the highly efficient generation of a pure, high order complex of the oligosaccharide target with synthetic carbohydrate receptor sites, in which the spatial arrangement of the multiple receptors in the complex is preserved upon material surface incorporation. The synthetic binding scaffolds can easily be tailored to recognize different oligosaccharides and glycoconjugates, opening up a realm of possibilities for their use in a wide field of applications, ranging from life sciences to diagnostics., A unique modular, synthetic strategy allows for the creation of artificial binding sites with precise spatial positioning of multiple carbohydrate receptors, enabling the remarkable ability to distinguish a target oligosaccharide over closely related carbohydrate structures. The synthetic binding scaffolds can easily be tailored to bind not only specifically oligosaccharides in free form but also when they are linked to proteins as glycoconjugates.

Natural structural materials, such as bone, can autonomously modulate their mechanical properties in response to external loading to prevent failure. These material systems smartly control the addition/removal of material in locations of high/low mechanical stress by utilizing local resources guided by biological signals. On the contrary, synthetic structural materials have unchanging mechanical properties limiting their mechanical performance and service life. Inspired by the mineralization process of bone, a material system that adapts its mechanical properties in response to external mechanical loading is reported. It is found that charges from piezoelectric scaffolds can induce mineralization from surrounding media. It is shown that the material system can adapt to external mechanical loading by inducing mineral deposition in proportion to the magnitude of the stress and the resulting piezoelectric charges. Moreover, the mineralization mechanism allows a simple one-step route for fabricating functionally graded materials by controlling the stress distribution along the scaffold. The findings can pave the way for a new class of self-regenerating materials that reinforce regions of high stress or induce deposition of minerals on the damaged areas from the increase in mechanical stress to prevent/mitigate failure. It is envisioned that the findings can contribute to addressing the current challenges of synthetic materials for load-bearing applications from self-adaptive capabilities.

Homeostatic systems combine an ability to maintain integrity over time with an incredible capacity for interactive behavior. Fundamental to such systems are building blocks of "mini-homeostasis": feedback loops in which one component responds to a stimulus and another opposes the response, pushing the module to restore its original configuration. Particularly when they cross time and length scales, perturbation of these loops by external changes can generate diverse and complex phenomena. Here, it is proposed that by recognizing and implementing mini-homeostatic modules-often composed of very different physical and chemical processes-into synthetic materials, numerous interactive behaviors can be obtained, opening avenues for designing multifunctional materials. How a variety of controlled, nontrivial material responses can be evoked from even simple versions of such synthetic feedback modules is illustrated. Moreover, random events causing seemingly random responses give insights into how one can further explore, understand and control the full interaction space. Ultimately, material fabrication and exploration of interactivity become inseparable in the rational design of such materials. Homeostasis provides a lens through which one can learn how to combine and perturb coupled processes across time and length scales to conjure up exciting behaviors for new materials that are both robust and interactive.

Biological materials exhibit anisotropic characteristics because of the anisometric nature of their constituents and their preferred alignment within interfacial matrices. The regulation of structural orientations is the basis for material designs in nature and may offer inspiration for man-made materials. Here, how structural orientation and anisotropy are designed into biological materials to achieve diverse functionalities is revisited. The orientation dependencies of differing mechanical properties are introduced based on a 2D composite model with wood and bone as examples; as such, anisotropic architectures and their roles in property optimization in biological systems are elucidated. Biological structural orientations are designed to achieve extrinsic toughening via complicated cracking paths, robust and releasable adhesion from anisotropic contact, programmable dynamic response by controlled expansion, enhanced contact damage resistance from varying orientations, and simultaneous optimization of multiple properties by adaptive structural reorientation. The underlying mechanics and material-design principles that could be reproduced in man-made systems are highlighted. Finally, the potential and challenges in developing a better understanding to implement such natural designs of structural orientation and anisotropy are discussed in light of current advances. The translation of these biological design principles can promote the creation of new synthetic materials with unprecedented properties and functionalities.

Greases enhance most mechanical equipment in terms of joint performance and operation age by reducing friction and wear. However, they are also considered a dangerous source of soil and water pollution because of their synthetic nature. Renewable resource-based materials are a safe and environmentally friendly solution. In the present work, a comprehensive study is conducted to evaluate the performance of existing synthetic and biodegradable greases. This work also provides insights into existing literature and presents ideas for future development through general recommendations regarding the use of renewable resource-based ingredients as a replacement for traditional synthetic materials in conventional greases.

Transcatheter aortic valve replacement has become today a largely considered alternative technique to surgical valve replacement in patients with high risk for open chest surgery. Biological valve tissue used in the transcatheter devices has shown success over 5 years now, but the procedure remains expensive. Moreover, different studies point out potential degradations that the tissue can undergo when folded to lower diameter and released in calcified environment with irregular geometry, which may jeopardize the durability of the device. The use of synthetic materials, like textile in particular, to replace biological valve leaflets would help reducing the procedure costs, and limit the degradations when the valve is crimped. Textile polyester material has been extensively used in the vascular surgery and is characterized by outstanding folding and strength properties combined with proven biocompatibility. However, the friction effects that occur between filaments and between yarns within a fabric under flexure loading could be critical for the resistance of the material on the long term. The purpose of this study was to assess the early fatigue performances of textile valve prototypes under accelerated cyclic loading up to 200 Mio cycles. Durability tests show that the fibrous material undergoes rearrangements between fibrous elements within the textile construction and the mechanical properties are modified on the long term. But testing is not complete with 200 Mio cycles. The material should be tested up to a higher number of cycles in future work to test the effective long-term durability. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 986-992, 2016.

Metal-organic frameworks (MOFs) are constructed by linking inorganic units with organic linkers to make extended networks. Though more than 20 000 MOF structures have been reported most of these are ordered and largely composed of a limited number of different kinds building units, and very few have multiple different building units (heterogeneous). Although heterogeneity and multiplicity is a fundamental characteristic of biological systems, very few synthetic materials incorporate heterogeneity without losing crystalline order. Thus, the question arises: how do we introduce heterogeneity into MOFs without losing their ordered structure? This Review outlines strategies for varying the building units within both the backbone of the MOF and its pores to produce the heterogeneity that is sought after. The impact this heterogeneity imparts on the properties of a MOF is highlighted. We also provide an update on the MOF industry as part of this themed issue for the 150th anniversary of BASF.

Natural materials have been a fundamental part of human life since the dawn of civilization. However, due to exploitation of natural resources and cost issues, synthetic materials replaced bio-derived materials in the last century. Recent advances in bio- and nano-technologies pave the way for developing eco-friendly materials that could be produced easily from renewable resources at reduced cost and in a broad array of useful applications. This feature article highlights structural and functional characteristics of bio-derived materials, which will expedite the design fabrication and synthesis of eco-friendly and recyclable advanced nano-materials and devices.

Disulfide bonds have frequently been incorporated into synthetic materials to promote sensitivity of the systems towards different redox environments. Although many strategies have been developed to rationally tune the stability of disulfide linkers, methods to tune their responsiveness towards different redox environments remain elusive. In this work we have developed and explored a disulfide linker bearing two independent disulfide bonds, referred to as a twin-disulfide linker. We have demonstrated that the twin-disulfide linker displays an ultrahigh stability at lower concentrations of reducing agent or in weakly reducing environments without a significant compromise in the sensitivity of its response to highly reducing environments such as cytoplasm, a feature that is in remarkable contrast to the traditional single disulfide bonds. Such an extraordinary responsiveness arises from the cooperativity of the twin-disulfide bonds, which should be of particular interest for applications such as controlled drug delivery and sensing, because relatively large differences in disulfide stability in different redox environments is desired in these applications.

Cells in vivo typically are found in 3D matrices, the mechanical stiffness of which is important to the cell and tissue-scale biological processes. Although it is well characterized that as to how cells sense matrix stiffness in 2D substrates, the scenario in 3D matrices needs to be explored. Thus, materials that can mimic native 3D environments and possess wide, physiologically relevant elasticity are highly desirable. Natural polymer-based materials and synthetic hydrogels could provide an better 3D platforms to investigate the mechano-response of cells with stiffness comparable to their native environments. However, the limited stiffness range together with interdependence of matrix stiffness and adhesive ligand density are inherent in many kinds of materials, and hinder efforts to demonstrate the true effects contributed by matrix stiffness. These problems have been addressed by the recently emerging exquisitely designed materials based on native matrix components, designer matrices, and synthetic polymers. In this review, a variety of materials with a wide stiffness range that mimic the mechanical environment of native 3D matrices and the independent affection of stiffness for cellular behavior and tissue-level processes are discussed.

The encapsulation of cells into polymeric microspheres or microcapsules has permitted the transplantation of cells into human and animal subjects without the need for immunosuppressants. Cell-based therapies use donor cells to provide sustained release of a therapeutic product, such as insulin, and have shown promise in treating a variety of diseases. Immunoisolation of these cells via microencapsulation is a hotly investigated field, and the preferred material of choice has been alginate, a natural polymer derived from seaweed due to its gelling conditions. Although many natural polymers tend to gel in conditions favorable to mammalian cell encapsulation, there remain challenges such as batch to batch variability and residual components from the original source that can lead to an immune response when implanted into a recipient. Synthetic materials have the potential to avoid these issues; however, historically they have required harsh polymerization conditions that are not favorable to mammalian cells. As research into microencapsulation grows, more investigators are exploring methods to microencapsulate cells into synthetic polymers. This review describes a variety of synthetic polymers used to microencapsulate cells. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 846–859, 2015.

The surgical repair or treatment of degenerative joint disease has traditionally involved the substitution of synthetic materials for one or both surfaces of the joint. Engineering thermoplastics, metals, and ceramics have either been widely accepted or experimentally evaluated for use as bearing surfaces in these prostheses. When engineering thermoplastics are used, the opposing surface is a metal or a ceramic, but metal-on-metal, metal-on-ceramic, and ceramic-on-ceramic have also been used or tested. Researchers have sought the opportunity to utilize materials with compressive mechanical properties more closely matching those of the natural articular cartilage. This review discusses the theory, testing, and application of elastomers for one bearing component of articular joint prostheses.

Fracture healing is a complex physiological process, which involves a well-orchestrated series of biological events. Repair of large bone defects resulting from trauma, tumours, osteitis, delayed unions, non-unions, osteotomies, arthrodesis and multifragmentary fractures is a current challenge of surgeons and investigators. Different therapeutic modalities have been developed to enhance the healing response and fill the bone defects. Different types of growth factors, stem cells, natural grafts (autografts, allografts or xenografts) and biologic- and synthetic-based tissue-engineered scaffolds are some of the examples. Nevertheless, these organic and synthetic materials and therapeutic agents have some significant limitations, and there are still no well-approved treatment modalities to meet all the expected requirements. Bone tissue engineering is a newer option than the traditional grafts and may overcome many limitations of the bone graft. To select an appropriate treatment strategy in achieving a successful and secure healing, more information concerning injuries of bones, their healing process and knowledge of the factors involved are required. The main goals of this work are to present different treatment modalities of the fractured bones and to explain how fractures normally heal and what factors interfere with fracture healing. This study provides an overview of the processes of fracture healing and discusses the current therapeutic strategies that have been claimed to be effective in accelerating fracture healing.

Tissue engineered acellular vascular grafts are an emerging concept in the development of vascular prostheses for the minimally invasive treatment of cardiovascular diseases. Extracellular matrix (ECM) scaffolds, such as small intestinal submucosa (SIS) and urinary bladder matrix (UBM), offer many advantages over currently available synthetic devices. However, storage of such biomaterials can unduly influence the scaffold properties. This study evaluated the effects of up to 16 weeks hydrated storage on the mechanical and cellular performance of stented and unstented tubular scaffolds. This study aimed to demonstrate the viability, mechanical integrity, and bioactive potential of xenogeneic ECMs as potential off-the-shelf vascular prosthetic devices. Rehydrated ECM samples versus the lyophilized controls showed an increase in UTS and stiffness. The mechanical strength of all samples evaluated was above the average reported aortic tissue failure strength and more compliant than current synthetic materials employed. Post-storage cellular bioactivity investigations indicated that both ECM scaffolds tested were unaffected by increased hydrated storage duration when compared with the controls. Overall, the results indicate that the biomechanical and biologic properties of ECMs are not negatively affected by long-term hydrated storage. Therefore, with further investigations, naturally derived ECM materials may offer potential as an off-the-shelf therapeutic treatment of cardiovascular diseases.

The current nano-biotechnologies interfacing synthetic materials and cell biology requires a better understanding of cell–surface interactions on the micro-to-nanometer scale. Cell–substrate interactions are mediated by the presence of proteins adsorbed from biological fluids to the substrate. The effect of nanotopography and surface chemistry on protein adsorption as well as the mediation effect on subsequent cellular communication with substratum is not well documented. This review discusses the role of physicochemical properties of cell–surface interactions and state-of-the-art methods currently available for micro-nanoscale surface fabrication and patterning. We also briefly discuss the current surface patterning techniques that allow the combination of a fine and independent control on nanotopography and chemistry to understand the effect of surface nanoscale substrate morphology on cell–surface interactions which has never been realized in previous reports. In addition, we discuss the influence of various chemical patterning and modulation of the nano-topography of surfaces on cell functionality and phenotype. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 3019–3032, 2013.

Molecular flasks are compounds that are able to mediate or catalyze chemical transformations inside their cavities. The development of such compounds is often inspired by nature. Enzymes, nature’s catalysts, are able to convert a certain substrate with very high turnover number and selectivity. In addition to their very high chemo-, regio-, and stereoselectivity, enzymes are also able to distinguish their substrates on the basis of size, resulting in size selectivity. To date, many synthetic materials such as metal–organic frameworks are used to accomplish size-selective transformations. However, also the number of molecular flasks known to mediate or catalyze size-selective transformations is increasing. In this perspective an overview on classic and the most recent examples of size-selective molecular flasks is given. In addition, an outlook on promising developments in cavity chemistry that may lead to the development of additional size-selective molecular flasks is given.

Biological composites have evolved elaborate hierarchical structures to achieve outstanding mechanical properties using weak but readily available building blocks. Combining the underlying design principles of such biological materials with the rich chemistry accessible in synthetic systems may enable the creation of artificial composites with unprecedented properties and functionalities. This bioinspired approach requires identification, understanding, and quantification of natural design principles and their replication in synthetic materials, taking into account the intrinsic properties of the stronger artificial building blocks and the boundary conditions of engineering applications. In this progress report, the scientific and technological questions that have to be addressed to achieve this goal are highlighted, and examples of recent research efforts to tackle them are presented. These include the local characterization of the heterogeneous architecture of biological materials, the investigation of structure-function relationships to help unveil natural design principles, and the development of synthetic processing routes that can potentially be used to implement some of these principles in synthetic materials. The importance of replicating the design principles of biological materials rather than their structure per se is highlighted, and possible directions for further progress in this fascinating, interdisciplinary field are discussed.

The desire to reduce healthcare costs while improving outcomes drives minimally invasive methods to replacing traditional surgical procedures. Various treatments that would previously have needed open-type surgeries can be carried out using endoscopes, catheters, and needles. These advantages have become especially obvious for tissue engineering and regenerative medicine with in vivo gel injectable nanomaterials. In this review, the state of the art in this rapidly developing field is given. This is done by contrasting functional evaluation in vitro with in vivo followed by describing (1) synthetic materials, (2) the body's own polymers, (3) polymers in nature, (4) self-assembled peptides, and (5) new innovations and combinations. With increased understanding of the relationship between material characteristics and the outcome in vivo more rational design criteria are emerging.

As a new generation of stationary phases, monolithic supports have attracted significant interest in high-performance liquid chromatography (HPLC) and capillary electrochromatography (CEC) because of their ease of preparation, high reproducibility, versatile surface chemistry and rapid mass transport. Molecularly imprinted polymers (MIPs) are synthetic materials with high specific recognition ability to template molecule. The combination of monolithic column and MIPs integrates the high efficiency of modern chromatography and the high selectivity provided by MIPs. This review focuses on the recent developments and applications of all kinds of monolithic matrix, i.e. organic polymer-based and silica-based MIP monolith in HPLC and CEC mode.

The ongoing surge in demand for high-performance energy storage systems inspires the relentless pursuit of advanced materials and structures. Components of energy storage systems are generally based on inorganic/metal compounds, carbonaceous substances, and petroleum-derived hydrocarbon chemicals. These traditional materials, however, may have difficulties fulfilling the ever-increasing requirements of energy storage systems. Recently, nanocellulose has garnered considerable attention as an exceptional 1D element due to its natural abundance, environmental friendliness, recyclability, structural uniqueness, facile modification, and dimensional stability. Recent advances and future outlooks of nanocellulose as a green material for energy storage systems are described, with a focus on its application in supercapacitors, lithium-ion batteries (LIBs), and post-LIBs. Nanocellulose is typically classified as cellulose nanofibril (CNF), cellulose nanocrystal (CNC), and bacterial cellulose (BC). The unusual 1D structure and chemical functionalities of nanocellulose bring unprecedented benefits to the fabrication and performance of energy storage materials and systems, which lie far beyond those achievable with conventional synthetic materials. It is believed that this progress report can stimulate research interests in nanocellulose as a promising material, eventually widening material horizons for the development of next-generation energy storage systems, that will lead us closer to so-called Battery-of-Things (BoT) era.

Although synthetic polymers are part of our global waste problem because they are not sufficiently biologically degraded, microorganisms can severely impair the properties and functions of these materials. It seems as if consumers do not really acknowledge this cause of problems and there is only sparse systematic research about. Damaging mechanisms include (i) covering of surfaces (biofouling) which may be enhanced by leaching of biodegradable additives, (ii) depletion of such additives which can lead to loss of material properties, (iii) intrusion into materials by fungal hyphae, (iv) water uptake, and (v) discoloration. The common countermeasure is the addition of biocides or simply to tolerate the effects of biodeterioration and live on with them. It is suggested to encourage further systematic research, and to develop integrated strategies in order to avoid problems, e.g., based on nutrient and water limitation whenever possible.

Several synthetic materials exhibiting contrast imaging properties have become vital to the field of biomedical imaging. Polymeric biomaterials and metals are commonly used imaging agents and can assist in the monitoring of therapy response, migration, degradation, changes in morphology, defects, and image-guided surgery. In comparison to metals, most bio and synthetic polymers lack inherent imaging properties. Polymeric biomaterials, specifically polyesters, have gained a considerable amount of attention due to their unique properties including biocompatibility, biodegradation, facile synthesis, and modification capability. Polyester implants and nanomaterials are available on the market or are in clinical trials for many applications including: dental implants, cranio-maxilofacial implants, soft tissue sutures and staples, abdominal wall repair, tendon and ligament reconstruction, fracture fixation devices, and coronary drug eluting stents. This review aims to provide a summary of the recent developments of polyesters with bioimaging contrast properties. The three main approaches to prepare bioimaging polyesters (coating, encapsulation, and functionalization) are discussed in depth. Furthermore, commonly used imaging modalities including X-ray computed tomography, magnetic resonance imaging, ultrasound, fluorescence, and radionucleotide polyester contrast agents are highlighted. In each section, examples of impactful bioimaging polyesters in the five major imaging modalities are evaluated.

Summary This paper presents a new computational solution to quantify the porosity of synthetic materials from optical microscopic images. The solution is based on an artificial neuronal network of the multilayer perceptron type and a backpropagation algorithm is used for training. To evaluate this new solution, 40 sample images of a synthetic material were analysed and the quality of the results was confirmed by human visual analysis. In addition, these results were compared with ones obtained with a commonly used commercial system confirming their superior quality and the shorter time needed. The effect of images with noise was also studied and the new solution showed itself to be more reliable. The training phase of the new solution was analysed confirming that it can be performed in a very easy and straightforward manner. Thus, the new solution demonstrated that it is a valid and adequate option for researchers, engineers, specialists and other professionals to quantify the porosity of materials from microscopic images in an automatic, fast, efficient and reliable manner.

INTRODUCTION In biological systems, motility is vital for survival; by fleeing from predators, large animals as well as single-cell organisms can live another day. A remarkable aspect of biological motility is the essentially seamless coordination of temporal and spatial events that lead to large-scale motion. As we take a step, we are unconscious of the series of interconnected dynamic processes, which encompass a range of length scales, involved in moving us forward. An intriguing scientific challenge is to replicate this type of seamless movement using synthetic materials. There are, however, significant differences between animate and inanimate objects that make this a particularly daunting task. One dramatic difference is that animate objects eat, and thus, they are self-sustaining, converting the energy from food to drive their motion. Hence, in devising biomimetic self-propelled objects, we must establish routes for making these materials capable of autonomously and dynamically transducing one form of energy into another to fuel their functionality.

Impaction bone grafting in revision arthroplasty is a common and successful procedure to restore primary bone stock. Reducing the amount of bone needed to fill large grafts has been a driving force for the use of synthetic materials that can act as extenders or substitutes. To this end, we evaluated the mechanical properties of a new class of biodegradable polymer beads with and without donor bone to determine its suitability for use in impaction grafting. Biodegradable methacrylated anhydride beads were synthesized using thermal polymerization techniques. The mechanical properties of the beads were then tested in an impaction grafting test chamber and compared with morsellised porcine allograft. The beads, porcine allograft and a 50/50 combination all had similar mechanical properties, both in compression and relaxation. Pure polymer beads compacted significantly less than pure allograft and retained macroporosity after impaction. Our results suggest that the biodegradable beads have sufficient mechanical properties to be considered as an impaction grafting substitute or extender. Their ability to fill space whilst retaining macroporosity may be advantageous for tissue ingrowth and remodeling. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.

Biomineralization is a highly dynamic, yet controlled, process that many living creatures employ to develop functional tissues such as tooth enamel, bone, and others. A major goal in materials science is to create bioinspired functional structures based on the precise organization of building blocks across multiple length scales. Therefore, learning how nature has evolved to use biomineralization could inspire new ways to design and develop synthetic hierarchical materials with enhanced functionality. Toward this goal, this review dissects the current understanding of structure-function relationships of dental enamel and bone using a materials science perspective and discusses a wide range of synthetic technologies that aim to recreate their hierarchical organization and functionality. Insights into how these strategies could be applied for regenerative medicine and dentistry are also provided.

Stimuli-responsive polymer microcapsules (PMs) fabricated by the sonochemical method have emerged for developing useful drug delivery systems, and the latest developments are mainly focusing on the synthetic strategies and properties such as structure, size, stability, loading capacity, drug delivery, and release. There, the primary attribution of sonochemistry is to offer a simple and practical approach for the preparation of PMs. Structure, size, stability, and properties of PMs are designed mainly according to synthetic materials, implementation schemes, or specific demands. Numerous functionalities of PMs based on different stimuli are demonstrated: targeting motion in a magnetic field or adhering to the living cells with sensitive sites through molecular recognition, and stimuli-triggered release including enzymatic catalysis, chemical reaction as well as physical or mechanical process. The current review discusses the basic principles and mechanisms of stimuli effects, and describes the progress in the application such as targeted drug systems and controlled drug systems, and also gives an outlook on the future challenges and opportunities for drug delivery and theranostics.

An emerging approach for design of dynamic materials involves mimicking natural systems, which are adept at changing their structure and function in response to their environment. Biological systems possess a diverse range of dynamic mechanisms, including competitive ligand―protein binding, enzyme-catalyzed remodeling, and allosteric protein conformational changes. These dynamic mechanisms are now being exploited by materials scientists and engineers to design "bioinspired" synthetic materials that undergo responsive assembly and disassembly as well as dynamic volume and shape changes. The purpose of this review is to describe recent progress in design and development of bioinspired dynamic materials, with a particular emphasis on hydrogel networks. We specifically focus on emerging approaches that use biological phenomena as an inspiration for design of materials.

Artificial cells consist of a hybrid system combining biological and synthetic materials. It has been investigated for enzyme therapy, erythrocyte substitution, hemoperfussion, artificial kidney, artificial liver, detoxification, immunoadsorbents and other applications.

The ability to replace or augment diseased body parts totally or partially has improved both the quality and life span of human population. The decline in surgical risks during recent decades has encouraged the development of more complex procedures for prosthetic implantation. Additionally, a variety of extracorporeal devices, such as the heart, lung and blood dialysis machines are used routinely, but these prosthetic elements have several limitations. Hence, research projects are currently underway to overcome the limitations of synthetic materials by developing formulations with varying properties, such as asymptomatic, long-term function in the human physiological environment, etc., to meet the needs of biomedical surgeons. This review focuses on the several biomaterials corrosion and its measures to prevent corrosion.

The hypothesis is advanced that electrical conduction and semiconduction properties of some natural biopolymers and synthetic polymers may have a relationship to blood compatibility. Newly developed impervious, thin carbon coatings perform best biologically when deposited on smooth polymeric and nonpolymeric surfaces. The biological performance of grafted polyacrylamide hydrogels is influenced by both substrate and hydrodynamic effects which may be more dominant in blood compatibility than surface energy forces. Although the latter are undoubtedly involved in bioadhesion, their contributions do not correlate well with the overall biological performance of synthetic materials. Species-related hematological differences of experimental animals, particularly calves, dogs, and primates, significantly influence the biological performance of materials which must be considered in the human application of medical devices in which biomaterials are in contact with blood.

Benzofuran heterocycles are fundamental structural units in a variety of biologically active natural products as well as synthetic materials. Over the time, benzofuran derivatives have attracted many researchers due to the broad scope of their biological activity, which include anticancer, antimicrobial, immunomodulatory, antioxidant and anti-inflammatory properties. Egonol, homoegonol and moracin families are biologically active natural products containing benzofuran heterocycle as basic structural units. This paper focuses on the moracin family (moracin A to Z). Morus, a genus of flowering plants in the family Moraceae, comprises 10-16 species of deciduous trees commonly known as mulberries. The root bark, stem bark and leaves of Morus alba, M. lhou, Morus macroura are the main sources for arylbenzofuran derivatives including the moracins. A large volume of research has been carried out on moracins and their derivatives, which has shown the pharmacological importance of this benzofuran heterocyclic nucleus. In this mini-review, we attempt to highlight the importance of moracins, as they have been a major source for drug development. Herein, we also summarize the current state of the art concerning the synthesis and medicinal use of moracins A-Z.

Aim: To compare the effectiveness of transurethral collagen injection and perineal bone-anchored male sling for the treatment of male stress urinary incontinence (SUI). Methods: Seventy-one men with SUI underwent either transurethral collagen injections (n = 34) or perineal bone-anchored male sling (n = 37) between June 1999 and October 2003. Most of the patients in each group had radical retropubic prostatectomy and/ or external beam radiation therapy (EBRT) in relation to the cause of incontinence. There was one patient in both groups who only had EBRT for the cause. The mean duration of incontinence were 4.2 and 4.4 years, respectively. Collagen injections were carried out transurethrally either under regional or general anesthesia until co-aptation of mucosa was observed. The male sling was placed under spinal anesthesia with a bone drill using either absorbable or synthetic materials. Retrospectively, all patients were assessed for continence status and procedure-related morbidity, if present. The outcome of both procedures was also compared with the degree of incontinence. Results: Ten (30%) patients in the collagen group showed either significant improvement or were cured following injections. Preoperatively, the mean pad use in collagen group was 4.5 (SD 2.8) per day, whereas it was 2.2 (SD 1.1) after the injection(s). Collagen injection failed in 24 (70%) of the patients. Patients who received the male sling had a mean preoperative pad use of 3.7 (SD 1.5) and postoperatively, the number decreased to 1.6 (SD 1.2). Most of the patients in this group were either totally dry or significantly improved (n: 28, 76%). There was a statistically significant difference between two groups in respect to success rate (P < 0.05). Analysis of treatment outcome with the degree of incontinence revealed that the male sling is most effective in patients with minimal-to-moderate incontinence. Conclusions: Our results suggest that the male sling, a minimally invasive procedure, is more effective than collagen implant in the treatment of mild-to-moderate SUI in men.

Physicochemical modification could implement synthetic materials into osteoinductive materials, which induce bone formation in nonosseous tissues. We hereby studied the relevance between the osteogenic capacities of osteoinductive materials in nonosseous tissues and in osseous sites. Biphasic calcium phosphate ceramic (BCP) and hydroxyapatite ceramic (HA) were implanted in femoral muscles and femoral cortical bone of dogs for 7, 14, 21, 30, 45, 60, 90, 180, and 360 days, respectively. Two dogs were used in each time point. In each dog, four cylinders (5 × 6 mm) per material were implanted in femoral muscles and 2 cylinders (5 × 6 mm) per material in femoral cortical bone. The harvested samples were processed for both histological and histomorphometric analyses. Bone was observed in BCP implanted in femoral muscles since day 30, while in HA since day 45. Quantitatively, more bone was formed in BCP than in HA at each time point after day 30 (p

WOS: 000243455300027, PubMed ID: 17120224, Calcium phosphate ceramics are generally biocompatible and can develop interactions with human recipient bone. Therefore, they can be widely used in the field of periodontology and dentistry. The purpose of this investigation was to assess the long-term histological bone healing results of experimentally created critical size parietal bone defects in rats. Twelve Wistar rats were used in this investigation. Two 6-mm wide, symmetrical, and circular critical size defects were created in each parietal bone of the animals. While the right defects filled with granular implant (Ceraform (R)), the symmetrical defects were taken as controls. Eighteen months after implantation, rats were killed and defects including the biomaterial with surrounding bone was taken for histological examination. Serial histological sections were cut across the defects and stained for the histological analysis. Both control and Ceraform implanted regions contained dense collagenous tissue. In the implantation site, multinuclear giant cells were observed around the material. On the other hand, there were no necrosis, tumour, and infection in the implantation region. There was no statistical difference between the control and ceraform implanted groups when the bone formation results were compared (p > 0.05). In conclusion, the results revealed that this material is biocompatible and does enhance the new bone building despite the long-term observation period. Although this biphasic ceramic shows within the limits of the study as a less resorptive and not osteoconductive properties, it can be considered as a biocompatible bone defect filling material having a limited application alternative in dentistry and medicine. (c) 2006 Wiley Periodicals, Inc.

Endodontic filling materials may be considered true implants as they touch and are based in vital tissues of the body, and protrude to meet the external surface directly or, more appropriately, indirectly via another surface restoration (Fig. 1). It follows that the materials must possess several different properties relative to their functions and location, ranging from biocompatibility to mechanical sealing ability. The first ‘root fillings’ were probably items wedged and fixed in root canals exposed by trauma or wear and causing pain to the individual. He, she or a helping associate would poke and scratch into the root with whatever item available, e.g. the bronze pin found in an upper canine of a roman soldier, exhumed in the Israeli desert some 1800 years after his death (1). The search for materials that would remedy the pains and problems associated with compromised pulps has been almost as haphazard up to this day. Most materials applied to other fields of dentistry have been tried also as endodontic filling materials, with variable, and at times disastrous, effects. Typically, focus has been on one particular property of the material advocated to be of primary significance for ‘success’, while disregarding other, in hindsight, more important aspects of the filling. One component of the root filling, the gutta-percha core, has however remained dominant in the various techniques and material combinations advocated for endodontic obturation for the past century and more. Silver points have had and still have proponents as an alternative, but their suitability has been questioned with reference to corrosion and clinical failures. Only during the past few years has the gutta-percha been seriously challenged by other, synthetic materials in the production of root fillings.

Heterocyclic compounds hold a special place among pharmaceutically important natural and synthetic materials. The remarkable ability of heterocyclic nuclei to serve both as biomimetics and reactive pharmacophores has largely contributed to their unique value as traditional key elements of numerous drugs. In both lead identification and optimization processes there is an acute need for new organic small molecules. Traditional methods of organic synthesis are orders of magnitude too slow to satisfy the demand for these compounds; so, the fields of combinatorial and automated medicinal chemistry have been developed to meet the increasing requirement of new compounds for drug discovery, within these fields, speed is of the essence. The efficiency of microwave flash-heating chemistry in dramatically reducing reaction times (reduced from days and hours to minutes and seconds) has recently been proven in several different fields of organic chemistry. We believe that the time saved by using focused microwaves is potentially important in traditional organic synthesis but could be of even greater importance in high-speed combinatorial and medicinal chemistry. In this review, it is impossible to cover all significant developments in the area of microwave-assisted organic synthesis (MAOS). Rather, outlines the basic principles behind the technology and summarizes the areas in which microwave technology has made an impact, to date. Specific attention is given to application of microwave technology in Combinatorial Organic Synthesis of several representative biologically interesting nuclei obtained both in liquid systems and in the solid state.