Enhancement of microalgal growth by using perfluorocarbon as oxygen carrier

The contribution of green microalgae has been recognized in the production of useful products such as chemicals, fatty acids, proteins, carotenoids, pigments, polysaccharides, and pharmaceuticals. One of the challenges to the development of profitable bioproduct markets is the design, development, modeling, and evaluation of cost-effective production systems. The photobioreactors for microalgae can be either open or closed systems in large-scale production. In various situations, it has been reported that closed photobioreactors offer many advantages over open systems. These advantages include lower contamination, higher biomass densities, and better process control. Nevertheless, for the scale-up of enclosed tubular photobioreactors, the accumulation of oxygen as a photosynthetic byproduct has been a major limitation because it severely inhibits growth of microalgae. In this study, we use the distinctive feature of liquid perfluorocarbons (PFCs) as a carrier that efficiently removes the accumulated oxygen from algal medium phase in the spinner culture flasks. The results show the growth kinetics of microalgae cultivated by this approach is significantly improved.     

Future prospects for vaccine adjuvants

Since the landmark experiments of Ramon 60 years ago, attempts have been made to augment the humoral and cellular responses to administered antigens in order to develop more potent and less toxic vaccines. The need for an acceptable adjuvant suitable for clinical use has been underscored by recent advances in recombinant biotechnology and synthetic chemistry which have made it possible to create antigens that are smaller and better characterized, yet less immunogenic, than before. It is likely that these antigens will require an adjuvant to achieve protective immunity. Some of these same technological advances, together with a better understanding of the immune system in general, have permitted the study of adjuvants to evolve from an empirical field to a developmental one. This article discusses the currently known agents capable of immunopotentiation and possible strategies for their use in future vaccines.     

Actinobacteria mediated synthesis of nanoparticles and their biological properties: A review

Abstract

Nanotechnology is gaining tremendous attention in the present century due to its expected impact on many important areas such as medicine, energy, electronics, and space industries. In this context, actinobacterial biosynthesis of nanoparticles is a reliable, eco-friendly, and important aspect of green chemistry approach that interconnects microbial biotechnology and nanobiotechnology. Antibiotics produced by actinobacteria are popular in almost all the therapeutic measures and it is known that these microbes are also helpful in the biosynthesis of nanoparticles with good surface and size characteristics. In fact, actinobacteria are efficient producers of nanoparticles that show a range of biological properties, namely, antibacterial, antifungal, anticancer, anti-biofouling, anti-malarial, anti-parasitic, antioxidant, etc. This review describes the potential use of the actinobacteria as the novel sources for the biosynthesis of nanoparticles with improved biomedical applications.     

Aptamers: multifunctional molecules for biomedical research

Aptamers are single-stranded oligonucleotides that fold into well-defined three-dimensional shapes, allowing them to bind their targets with high affinity and specificity. They can be generated through an in vitro process called “Systemic Evolution of Ligands by Exponential Enrichment” and applied for specific detection, inhibition, and characterization of various targets like small organic and inorganic molecules, proteins, and whole cells. Aptamers have also been called chemical antibodies because of their synthetic origin and their similar modes of action to antibodies. They exhibit significant advantages over antibodies in terms of their small size, synthetic accessibility, and ability to be chemically modified and thus endowed with new properties. The first generation of aptamer drug “Macugen” was available for public use within 25 years of the discovery of aptamers. With others in the pipeline for clinical trials, this emerging field of medical biotechnology is raising significant interest. However, aptamers pose different problems for their development than for antibodies that need to be addressed to achieve practical applications. It is likely that current developments in aptamer engineering will be the basis for the evolution of improved future bioanalytical and biomedical applications. The present review discusses the development of aptamers for therapeutics, drug delivery, target validation and imaging, and reviews some of the challenges to fully realizing the promise of aptamers in biomedical applications.     

Design of modular non-viral gene therapy vectors

Gene delivery has numerous potential applications both clinically and for basic science research. Non-viral vectors represent the long-term future of gene therapy and biomaterials are a critical component for the development of efficient delivery systems. Biomaterial development combined with fundamental studies of virus function and cellular processes will enable the molecular level design of modular vectors. Vectors are being developed based on cationic polymers or lipids that contain functional groups to mediate appropriate interactions with the extracellular environment or to interface with specific cellular processes. This review describes recent progress on the development of biomaterials for non-viral vectors and highlights opportunities for future development. Ultimately, efficient vectors will expand the traditional applications of gene therapy within the clinic and may enable numerous other opportunities within diagnostics, biotechnology, and basic science research.     

Stem cell-derived cell-sheets for connective tissue engineering

ABSTRACT

Cell-sheet technology involves the recovery of cells with its secreted ECM and cell–cell junctions intact, and thereby harvesting them in a single contiguous layer. Temperature changes coupled with a thermoresponsive polymer grafted culture plate surface are typically used to induce detachment of this cell–matrix layer by controlling the hydrophobicity and hydrophilicity properties of the culture surface. This review article details the genesis and development of this technique as a critical tissue-engineering tool, with a comprehensive discussion on connective tissue applications. This includes applications in the myocardial, vascular, cartilage, bone, tendon/ligament, and periodontal areas among others discussed. In particular, further focus will be given to the use of stem cells-derived cell-sheets, such as those involving bone marrow-derived and adipose tissue-derived mesenchymal stem cells. In addition, some of the associated challenges faced by approaches using stem cells-derived cell-sheets will also be discussed. Finally, recent advances pertaining to technologies forming, detaching, and manipulating cell-sheets will be covered in view of the potential impact they will have on shaping the way cell-sheet technology will be utilized in the future as a tissue-engineering technique.     

The potential impact of the preparation rich in growth factors (PRGF) in different medical fields

Platelet-rich preparations constitute a relatively new biotechnology for the stimulation and acceleration of tissue healing and bone regeneration. The versatility and biocompatibility of this approach has stimulated its therapeutic use in numerous medical and scientific fields including dentistry, oral implantology, orthopaedics, ulcer treatment, tissue engineering among others. Here we discuss the important progress that has been accomplished in the field of platelet-rich preparations in the last few years. Some of the most interesting therapeutic applications of this technology are discussed as are some of the limitations, future challenges and directions in the field.     

Challenges and approaches to the culture of pluripotent human embryonic stem cells

Since the establishment of the first human embryonic stem cell (hESC) lines, several groups have described the derivation and culture of hESC lines in various culture conditions. In this review, we describe how hESC lines have been derived from the inner cell mass of blastocysts or morula-stage embryos and the culture conditions used. In order to be used for therapeutic purposes, the pluripotent hESC lines must be established and propagated according to good manufacturing practice quality requirements. In addition, any use of animal-derived components should be avoided to gain safer hESC lines for clinical purposes. Here, we will describe the development in derivation and chemically defined culturing conditions of hESC towards good manufacturing practice and discuss the future challenges for hESCs in clinical use. Similarly, we discuss the challenges and future directions in optimization of standard culture conditions of hESCs for research purposes.     

In vivo molecular targeted radiotherapy

Unsealed radionuclides have been in clinical therapeutic use for well over half a century. Following the early inappropriate clinical administrations of radium salts in the early 20th century, the first real clinical benefits became evident with the use of (131)I-sodium iodide for the treatment of hypothyroidism and differentiated thyroid carcinoma and (32)P-sodium phosphate for the treatment of polycythaemia vera. In recent years the use of bone seeking agents (89)Sr, (153)Sm and (186)Re for the palliation of bone pain have become widespread and considerable progress has been evident with the use of (131)I-MIBG and (90)Y-somatostatin receptor binding agents. Although the use of monoclonal antibody based therapeutic products has been slow to evolve, the start of the 21st century has witnessed the first licensed therapeutic antibody conjugates based on (90)Y and (131)I for the treatment of non-Hodgkin's lymphoma. The future clinical utility of this form of therapy will depend upon the development of radiopharmaceutical conjugates capable of selective binding to molecular targets. The availability of some therapeutic radionuclides such as (188)Re produced from the tungsten generator system which can produce activity as required over many months, may make this type of therapy more widely available in some remote and developing countries.Future products will involve cytotoxic radionuclides with appropriate potency, but with physical characteristics that will enable the administration of therapeutic doses with the minimal need for patient isolation. Further developments are likely to involve molecular constructs such as aptamers arising from new developments in biotechnology.Patient trials are still underway and are now examining new methods of administration, dose fractionation and the clinical introduction of alpha emitting radiopharmaceutical conjugates. This review outlines the history, development and future potential of these forms of therapy.     

Tissue engineering in the USA

Tissue engineering is the application of the principles and methods of engineering and the life sciences towards the development of biological substitutes to restore, maintain or improve functions. It is an area which is emerging in importance worldwide. In the USA it has been actively fostered by the National Science Foundation, both through research grants and the sponsorship of a series of workshops starting in 1988. This brief review of activities in the USA focuses on cell culture technology as a foundation for tissue engineering and then discusses examples of applications. These include artificial skin and the use of encapsulated cells in the development of bioartificial organs. Also discussed is the reconstitution of a blood vessel in culture, both for use in basic research and for implantation as an artificial blood vessel in bypass surgery. In conclusion, other potential applications are mentioned as well as generic areas of technology for future development.     

Spatial control of cells,peptide delivery and dynamic monitoring of cellular physiology with chitosan-assisted dual color quantum dot FRET peptides

Cell-based assays have become important tools in the pharmaceutical and biotechnology industries. However, observing and monitoring molecules in cells that mimic the physiological environment is often difficult. Dynamic processes not only increase the accuracy of simulations, but also improve our understanding of the function and regulation of molecules within cells. In this study we used chitosan as a multifunctional biomaterial for selective micropatterning of cells, peptide delivery and covalent bonding with quantum dots (QD) to decrease the cytotoxicity of QD. Our results demonstrate the efficacy of chitosan–QD–peptide–Alexa Fluor 488 in controlling the spread and spatial organization of cells. Cationic chitosan also provided an efficient delivery mechanism to live cells. We used the shift from green to red fluorescence of the chitosan dual color QD peptide to detect biological activity. This methodology has potential applications in high throughput screening of inhibitors and activators of biological mechanisms and pathways and for use in the pharmaceutical industry.     

Crustacean primary cell culture: A technical approach

Crustacean cell culture has gained attention as a potent model to assist in the development of diagnostic reagents and probes for use in the shrimp, crayfish and lobster industries. The availability of such cellular tools is especially important to industries which use intensive aquaculture methods and thus have increased risk of disease problems. Indeed, crustacean cell cultures offer potential for studying the effects of pathogens in vitro and for increasing our knowledge on developmental and sexual maturation processes, or endocrine regulation in crustaceans. Although numerous attempts have been undertaken, no established cell line of marine crustaceans has been reported to date. However, primary cultures obtained from various organ sources are reported with increasing frequency. They represent the first steps towards the establishment of cell lines and they provide useful information concerning the most suitable cell culture conditions involved in the survival and proliferative capacity of the various tissues.     

Importance of lactobacilli in food and feed biotechnology

The genus Lactobacillus is a heterogeneous group of lactic acid bacteria (LAB) with important implications in food fermentation. The ability to colonize a variety of habitats is a direct consequence of the wide metabolic versatility of this group of LAB. Consequently, lactobacilli have been used for decades in food preservation, as starters for dairy products, fermented vegetables, fish and sausages as well as silage inoculants. Lactobacilli have also been proposed as probiotics and microbial cell factories for the production of nutraceuticals. However, a wide range of applications of lactobacilli in food biotechnology remains potential, whereas a number of important strains still need to be discovered and characterized. This article provides an overview of the taxonomy of lactobacilli and describes four of the most significant case studies on the application of this group of LAB in food and feed biotechnology, including their use as probiotics, dairy starters, silage inoculants, and microbial cell factories. The importance of access to and exchange of biological material within and between different strain collections as a crucial step in expanding the range of different biotechnological applications of lactobacilli is also emphasized.     

Stimuli responsive elastin-like polypeptides and applications in medicine and biotechnology

Elastin-like polypeptides (ELPs) are artificial biopolymers composed of the pentapeptide repeat Val–Pro–Gly–Xaa–Gly. They are a class of stimuli responsive biopolymers exhibiting an inverse temperature transition, which are particularly attractive in biological applications. In this paper, the methods of synthesizing ELPs and the applications in medicine and biotechnology such as purification of fusion proteins, drug delivery, and tissue engineering are reviewed. In addition, further perspective will be presented.     

Chemical Vapor Deposition for Solvent‐Free Polymerization at Surfaces

Chemical vapor deposition (CVD) methods are a powerful technology for engineering surfaces. When CVD is combined with the richness of organic chemistry, the resulting polymeric coatings, deposited without solvents, represent an enabling technology in many different fields of application. This article focuses on initiated chemical vapor deposition (iCVD), a new technique that utilizes benign reaction conditions to yield conformal and functional polymer thin films. The latest achievements in coating surfaces and 3D substrates with functional materials, and the use of the technique for biotechnology and selective permeation applications are reviewed, and future directions for iCVD technology are discussed.     

Quantitative real-time PCR in cancer research

In the era of the Human Genome Project, quantitation of gene expression by tumor/host cells is of paramount importance to investigate gene patterns responsible for cancer development, progression and response/resistance to treatment. Quantitative real-time PCR (qrt-PCR) technology has recently reached a level of sensitivity, accuracy and practical ease that support its use as a routine bioinstrumentation for gene level measurement. Several applications have been already implemented in the field of cancer research, and others are being validated, showing that this molecular biology tool can provide both researchers and clinicians with precious information concerning the behaviour of tumors. The knowledge of the biochemical principles underlying this biotechnology can be of great value to correctly interpret qrt-PCR data.     

Technology in health care: the social impact and economic cost

The contribution of technology to longevity and the quality of life has been substantial during the twentieth century. In the past two decades, technology employed in the care of hospitalized patients has been responsible for most of the cost by which the medical inflation rate (Medical Economic Index) exceeds the consumer price index. In most instances, the marginal benefit from the incremental cost is too small to be measured. If this viewpoint is correct, and if governments continue to contain medical costs, the future use of technology will be limited to those applications which have a clearly demonstrable marginal benefit associated with their incremental cost.     

Large-scale expansion of mammalian neural stem cells: a review

A relatively new approach to the treatment of neurodegenerative diseases is the direct use of neural stem cells (NSCs) as therapeutic agents. The expected demand for treatment from the millions of afflicted individuals, coupled with the expected demand from biotechnology companies creating therapies, has fuelled the need to develop large-scale culture methods for these cells. The rapid pace of discovery in this area has been assisted through the use of animal model systems, enabling many experiments to be performed quickly and effectively. This review focuses on recent developments in expanding human and murine NSCs on a large scale, including the development of new serum-free media and bioreactor protocols. In particular, engineering studies that characterise important scale-up parameters are examined, including studies examining the effects of long-term culture of NSCs in suspension bioreactors. In addition, recent advances in the human NSC system are reviewed, including techniques for the evaluation of NSC characteristics.     

组织工程化皮肤及临床应用研究进展

皮肤是人体最大的器官组织,是机体与外界环境接触的屏障。具有保护、分泌、代谢和感觉等重要功能。当由于外界损伤或疾病等因素造成皮肤缺损时,可造成屏障功能丧失,可以造成感染、水电解质失衡、免疫低下、多脏器衰竭甚至是致命的。自1975年,Rheinwald和Green以3T3细胞作为滋养层连续培养人类表皮角阮细胞获得成功,为组织工程化皮肤提供了坚实的理论和实践基础。随后,胶原海绵、脱细胞基质以及自体或异体细胞复合皮肤产品或商品应运而生。近年来,干细胞研究、转基因技术又为组织工程增加了更强的生命力。本文对组织工程皮肤及其临床应用进展进行了综述。