Aptamer-based biosensors: biomedical applications

This chapter considers the use of aptamer-based biosensors (generally termed 'aptasensors') in various biomedical applications. A comparison of antibodies and aptamers is made with respect to their use in the development of biosensors. A brief introduction to biosensor design and theory is provided to illustrate the principles of the field. Various transduction approaches, viz. optical, fluorescence, acoustic wave and electrochemical, are discussed. Specific biomedical applications described include RNA folding, high-throughput screening of drugs, use as receptors for measuring biological concentrations, detection of platelet-derived growth factor, protein binding and detection of HIV-1 Tat protein.     

Introduction to fiber optics: Sensors for biomedical applications

The paper focuses on the introduction of fiber optics, a fusion of science and engineering and describes the materials generally used for its construction along with the procedure used to design the fibers. It gives an idea of the materials used for the construction along with the pros and cons associated with them and various factors governing the emission of ultraviolet, infrared or visible radiations. The central core revolves around the applications of optical fibers in the medical and biomedical field and extending the use of the same in pharmaceutical industry as probes in quality control and dosage form analysis.     

Hydroxyapatite recovery from fish byproducts for biomedical applications

The solid waste that is generated during industrial fish processing causes environmental deterioration after it is discarded. However, these aquatic materials are a source of valuable compounds such as hydroxyapatite (HAp). HAp is a calcium phosphate with physicochemical and biological properties that are similar to those of native human bone. HAp has been used in biomedical material development because it is biocompatible and does not cause adverse effects. It has been combined with many other chemical compounds to improve their mechanical, structural, and bioactive properties and has noteworthy application benefits in the food supplement, drug delivery, cosmetology, odontology, and bone implant fields. In this review, recent research related to the isolation of HAp and the development of materials with health benefits due to its bioactive properties are discussed. Moreover, the HAp derived from industrial fish processing adds value to the byproduct and reduces the environmental risks caused by aquatic waste disposal in landfills.     

Neuropeptide-derived antimicrobial peptides from invertebrates for biomedical applications

Since the beginning of the 20th century, important medicinal progress has led medical doctors to think that the end of devastating epidemics has arrived. In 1930, the discovery of sulfamides and penicillin opened a wide area of applications able to fight against bacterial infections. However, almost all antibiotics were baffled by the great ability to adaptation of bacteria (1) and the emergence of new bacterial agents, discovered with up-dated technologies. The living world is perpetually in co-evolution and since more than 3 billion years, bacteria have developed resistance mechanisms to overcome external aggressions. Thus, in the middle of the 80th century, multi-resistant bacteria appeared and disseminated out from hospitals. In this context, researches have been developed in order to find new antimicrobial substances to destroy such new types of bacteria. Thus, several groups have turned their focus on invertebrates, which co-evoluad with human and have appeared on the planet since a long time. Evidence of new families of antimicrobial substances isolated from invertebrates different to the classical cationic peptide family i.e. dipeptides and anionic peptides been given. Moreover, these molecules are also present in human and may serve in the innate immune response as an important survival strategy.     

Hydrogels for biomedical applications

This article reviews the composition and synthesis of hydrogels, the character of their absorbed water, and permeation of solutes within their swollen matrices. The most important properties of hydrogels relevant to their biomedical applications are also identified, especially for use of hydrogels as drug and cell carriers, and as tissue engineering matrices.     

Ribosome-inactivating proteins: current status and biomedical applications

Ribosome-inactivating proteins (RIPs) are mainly present in plants and function to inhibit protein synthesis through the removal of adenine residues from eukaryotic ribosomal RNA (rRNA). They are broadly classified into two groups: type I and type II. Type I RIPs are a diverse family of proteins comprising a single polypeptide chain, whereas type II RIPs are heterodimeric glycoproteins comprising an A-chain (functionally equivalent to a type I RIP) linked via a disulphide bond to a B chain, mediating cell entry. In this review, we describe common type I and type II RIPs, their diverse biological functions, mechanism of cell entry, stability in plasma and antigenicity. We end with a discussion of promising applications for RIPs in biomedicine.     

Development of 3D bioprinting: From printing methods to biomedical applications

Biomanufacturing of tissues/organs in vitro is our big dream, driven by two needs: organ transplantation and accurate tissue models. Over the last decades, 3D bioprinting has been widely applied in the construction of many tissues/organs such as skins, vessels, hearts, etc., which can not only lay a foundation for the grand goal of organ replacement, but also be served as in vitro models committed to pharmacokinetics, drug screening and so on. As organs are so complicated, many bioprinting methods are exploited to figure out the challenges of different applications. So the question is how to choose the suitable bioprinting method? Herein, we systematically review the evolution, process and classification of 3D bioprinting with an emphasis on the fundamental printing principles and commercialized bioprinters. We summarize and classify extrusion-based, droplet-based, and photocuring-based bioprinting methods and give some advices for applications. Among them, coaxial and multi-material bioprinting are highlighted and basic principles of designing bioinks are also discussed.     

Marine polysaccharides: therapeutic efficacy and biomedical applications

The ocean contains numerous marine organisms, including algae, animals, and plants, from which diverse marine polysaccharides with useful physicochemical and biological properties can be extracted. In particular, fucoidan, carrageenan, alginate, and chitosan have been extensively investigated in pharmaceutical and biomedical fields owing to their desirable characteristics, such as biocompatibility, biodegradability, and bioactivity. Various therapeutic efficacies of marine polysaccharides have been elucidated, including the inhibition of cancer, inflammation, and viral infection. The therapeutic activities of these polysaccharides have been demonstrated in various settings, from in vitro laboratory-scale experiments to clinical trials. In addition, marine polysaccharides have been exploited for tissue engineering, the immobilization of biomolecules, and stent coating. Their ability to detect and respond to external stimuli, such as pH, temperature, and electric fields, has enabled their use in the design of novel drug delivery systems. Thus, along with the promising characteristics of marine polysaccharides, this review will comprehensively detail their various therapeutic, biomedical, and miscellaneous applications.     

Phototriggered structures: Latest advances in biomedical applications

Non-invasive control of the drug molecules accessibility is a key issue in improving diagnostic and therapeutic procedures. Some studies have explored the spatiotemporal control by light as a peripheral stimulus. Phototriggered drug delivery systems (PTDDSs) have received interest in the past decade among biological researchers due to their capability the control drug release. To this end, a wide range of phototrigger molecular structures participated in the DDSs to serve additional efficiency and a high-conversion release of active fragments under light irradiation. Up to now, several categories of PTDDSs have been extended to upgrade the performance of controlled delivery of therapeutic agents based on well-known phototrigger molecular structures like o-nitrobenzyl, coumarinyl, anthracenyl, quinolinyl, o-hydroxycinnamate and hydroxyphenacyl, where either of one endows an exclusive feature and distinct mechanistic approach. This review conveys the design, photochemical properties and essential mechanism of the most important phototriggered structures for the release of single and dual (similar or different) active molecules that have the ability to quickly reason of the large variety of dynamic biological phenomena for biomedical applications like photo-regulated drug release, synergistic outcomes, real-time monitoring, and biocompatibility potential.     

Poly(amidoamine) (PAMAM) dendrimers: from biomimicry to drug delivery and biomedical applications

Poly(amidoamine) (PAMAM) dendrimers are the first complete dendrimer family to be synthesized, characterized and commercialized. Based on this extensive activity, they are recognized as a unique new class of synthetic nanostructures. Dendrimers allow the precise control of size, shape and placement of functional groups that is desirable for many life science applications. From this perspective, this review focuses on crucial properties of biomimetic dendrimers that will broaden the potential for their use as macromolecular vectors in novel drug delivery and biomedical applications.     

Microbial exo-polysaccharides for biomedical applications

The productions and applications of various microbial exopolysaccharides have been under intensive researches over the past few decades. Some of these exopolysaccharides are commercial available and some are currently under intensive development; they include ionic heteropolysaccharide and neutral homopolysaccharide. These extracellular polymers constitute a structurally diverse class of biological macromolecules with a wide range of physiochemical properties which are the basis for the different applications in the broad fields of pharmacy and medicine. They have found applications in such diverse biomedical fields as ophthalmology, orthopedic surgery, tissue engineering, implantation of medical devices and artificial organs, prostheses, dentistry, bone repair and drug delivery.     

Hydrogels for biomedical applications.

This article reviews the composition and synthesis of hydrogels, the character of their absorbed water, and permeation of solutes within their swollen matrices. The most important properties of hydrogels relevant to their biomedical applications are also identified, especially for use of hydrogels as drug and cell carriers, and as tissue engineering matrices.     

Stimulus-responsive liposomes for biomedical applications

Liposomes are amphipathic lipidic supramolecular aggregates that are able to encapsulate and carry molecules of both hydrophilic and hydrophobic nature. They have been widely used as in vivo drug delivery systems for some time because they offer features such as synthetic flexibility, biodegradability, biocompatibility, low immunogenicity, and negligible toxicity. In recent years, the chemical modification of liposomes has paved the way to the development of smart liposome-based drug delivery systems, which are characterized by even more tunable and disease-directed features. In this review, we highlight the different types of chemical modification introduced to date, with a particular focus on internal stimuli-responsive liposomes and prodrug activation.     

Glycopeptide dendrimers for biomedical applications

Combinatorial libraries of peptide dendrimers bearing two and four copies of C-fucosyl residues were screened for binding to fucose specific lectins leading to potent ligands for Ulex europaeus lectin UEA-I (IC(50) = 11 microM). The dendrimers also show high affinity for the lectin PA-IIL (IC(50) = 0.14 microM) from the pathogenic bacteria Pseudomonas aeruginosa. The dendrimers described are the first multivalent ligands for these lectins. In our system, glycopeptide dendrimer-protein binding is modulated by the nature of the amino acid residues present in the dendritic structure instead of depending solely on the number of sugars attached to the scaffold. Studies of colchicine-glycopeptide dendrimer conjugates with improved selectivity for cancer cells in comparison to colchicine are also described.     

Leeches: immune response,angiogenesis and biomedical applications

The innate immune response is the first line of defence strategies in invertebrates against attack of infectious agents. A detailed analysis of the immune mechanisms involved in annelids has been performed in oligochaets, but few data are available in polichaets and hirudineans. The aim of this review is to describe the responses of leeches to different kinds of stimuli (infections following non-self agent attacks, surgical lesions, grafts). Furthermore, the use of this invertebrate as a novel experimental model to be used to screen drugs and genes, which are responsible for positive and negative modulation of angiogenesis, is discussed.     

Cell microencapsulation technology for biomedical purposes: novel insights and challenges

The aim of cell microencapsulation technology is to treat multiple diseases in the absence of immunosuppression. Using this technique, cells are immobilized within carefully designed capsules that allow the long-term function of the graft. Although the potential impact of this field is likely to be wide-ranging, the past few years have seen several 'firsts' that have brought the whole technology much closer to a realistic clinical application.     

Thermoresponsive hydrogels in biomedical applications: A seven-year update

Thermally responsive hydrogels modulate their gelation behavior upon temperature change. Aqueous solutions solidify into hydrogels when a critical temperature is reached. In biomedical applications, the change from ambient temperature to physiological temperature can be employed. Their potential as in situ forming biomaterials has rendered these hydrogels very attractive. Advances in drug delivery, tissue engineering and cell sheet engineering have been made in recent years with the use of thermoresponsive hydrogels. The scope of this article is to review the literature on thermosensitive hydrogels published over the past seven years. The article concentrates on natural polymers as well as synthetic polymers, including systems based on N-isopropylacrylamide (NIPAAm), poly(ethylene oxide)–b-poly(propylene oxide)–b-poly(ethylene oxide) (PEO–PPO–PEO), poly(ethylene glycol) (PEG)-biodegradable polyester copolymers, poly(organophosphazenes) and 2-(dimethylamino) ethyl methacrylate (DMAEMA).     

Nanoparticles: functionalization and multifunctional applications in biomedical sciences

Rapid innovations in nanomedicine have increased the likelihood that engineered nanomaterials will eventually come in contact with humans and the environment. The advent of nanotechnology has created strong interest in many fields such as biomedical sciences and engineering field. Central to any significant advances in nanomaterial based applications will be the development of functionalized nanoparticles, which are believed to hold promise for use in fields such as pharmaceutical and biomedical sciences. Early clinical results have suggested that functionalization of nanoparticles with specific recognition chemical moieties indeed yields multifunctional nanoparticles with enhanced efficacy, while simultaneously reducing side effects, due to properties such as targeted localization in tumors and active cellular uptake. A prerequisite for advancing this area of research is the development of chemical methods to conjugate chemical moieties onto nanoparticles in a reliable manner. In recent years a variety of chemical methods have been developed to synthesize functionalized nanoparticles specifically for drug delivery, cancer therapy, diagnostics, tissue engineering and molecular biology, and the structure-function relationship of these functionalized nanoparticles has been extensively examined. With the growing understanding of methods to functionalize nanoparticles and the continued efforts of creative scientists to advance this technology, it is likely that functionalized nanoparticles will become an important tool in the above mentioned areas. Therefore, the aim of this review is to provide basic information on nanoparticles, describe previously developed methods to functionalize nanoparticles and discuss their potential applications in biomedical sciences. The information provided in this review is important in regards to the safe and widespread use of functionalized nanoparticles particularly in the biomedicine field.