Design and development of pH-responsive HSPC:C12H25-PAA chimeric liposomes

The application of stimuli-responsive medical practices has emerged, in which pH-sensitive liposomes figure prominently. This study investigates the impact of the incorporation of different amounts of pH-sensitive polymer, C₁₂H₂₅-PAA (poly(acrylic acid) with a hydrophobic end group) in l-α-phosphatidylcholine, hydrogenated (Soy) (HSPC) phospholipidic bilayers, with respect to biomimicry and functionality. PAA is a poly(carboxylic acid) molecule, classified as a pH-sensitive polymer, whose pH-sensitivity is attributed to its regulative –COOH groups, which are protonated under acidic pH (pKa ～4.2). Our concern was to fully characterize, in a biophysical and thermodynamical manner, the mixed nanoassemblies arising from the combination of the two biomaterials. At first, we quantified the physicochemical characteristics and physical stability of the prepared chimeric nanosystems. Then, we studied their thermotropic behavior, through measurement of thermodynamical parameters, using Differential Scanning Calorimetry (DSC). Finally, the loading and release of indomethacin (IND) were evaluated, as well as the physicochemical properties and stability of the nanocarriers incorporating it. As expected, thermodynamical findings are in line with physicochemical results and also explain the loading and release profiles of IND. The novelty of this investigation is the utilization of these pH-sensitive chimeric advanced Drug Delivery nano Systems (aDDnSs) in targeted drug delivery which relies entirely on the biophysics and thermodynamics between such designs and the physiological membranes and environment of living organisms.     

A special issue of the Australian society for Biophysics

On behalf of the Australian Society for Biophysics (ASB) and the Editors of this Special Issue, I would like to express our appreciation to Editor-in-Chief, Damien Hall, for arranging the publication of this Special Issue. The ASB is about five times smaller than our sister the Biophysical Society for Japan (BSJ) and tenfold smaller than the US Biophysical Society (USBS), but our meetings are notable because of the encouragement the Society gives to emerging biophysicists. It can be a terrifying experience for a PhD student to have to face a roomful of professors and senior academics, but invariably they appreciate the experience. Another feature of the ASB meetings is the inclusion of contributions from the Asian Pacific region. We now have formal ties with our New Zealand colleagues and our meetings with the BSJ contain joint sessions (see below). In 2020, despite the impact of COVID-19 (see Adam Hill’s Commentary), there is a joint session with the University of California Davis. This Special Issue comprises 2 Editorials, 3 Commentaries, and 25 reviews.

When we began to put together an editorial on the contributions to this Special Issue of the 44th meeting of the Australian Society for Biophysics (ASB), we were struck by the sheer diversity of what we call “Biophysics”. Biophysics is actually not easy to define. The glib answer is “Biophysics is what biophysicists do”, but what do they do? If we asked an Australian Minister for Science to tell us what biophysicists do, he or she could tell us what immunologists and virologists do, but would probably have no idea what a biophysicist does. So how should we explain biophysics to the Minister? The US Biophysical Society defines “biophysics” as the field that applies the theories and methods of physics to understand how biological systems work. Operationally, biophysicists analyse the structure of biological molecules like DNA and proteins, they develop computer models to understand how drugs bind to the receptors in the body, and they investigate how gene mutations change the function of proteins.We thought a good example of biophysics research is the article by Boris Martinac at the beginning of this Special Issue. Boris has worked for much of his research life on trying to figure out how a mechanosensitive ion channel works. His “babies” are molecules encoded by the MscL and MscS genes and more recently also by the Piezo1 gene. He realised that bacteria needed to have sensors embedded in their surface membrane so they can quickly produce electrical or chemical signals in response to a mechanical force which occurs in the form of osmotic pressure. This of course is what enables the bacterium to survive when exposed to a hypoosmotic shock. More recently he and his colleagues turned their attention to investigating whether Piezo1 channels are the inherently mechanosensitive channels in vertebrates (Syeda et al. 2016) like MscL and MscS channels are in bacteria. They explained how Piezo receptors respond to changes in mechanical curvature of the cell membranes that open non-specific cation channels, thereby generating an electrical signal. In 2013 Boris was elected to the Australian Academy of Science in recognition of his discovery of bacterial mechanosensitive channels and the physical principles of mechanosensitive channel gating. More recently his work has expanded into the roles of mechanosensitive channels in nerves and heart disease. While we all hope he would get the “big” prize in science, it was his colleague, Ardem Patapoutian, who was awarded a share for the 2021 Nobel Prize in Physiology or Medicine for his research on Piezo1 and Piezo2.The 44th meeting of the Australian Society for Biophysics (ASB) was notable for two other reasons. It was either despite the fact or because it was a virtual meeting that the Society concurrently ran an international symposium with our sister society in Japan the Japanese Society for Biophysics. There is a close connection between the ABS and JSB. For years they have encouraged Australian biophysicists to travel to the large JSB meetings in Japan and they regularly send a strong contingent to Australia. A lot of hard work was put in by Kumiko Hayashi and her colleagues Risa Shibuya and Emi Hibino and the meeting attracted Japanese biophysicists from Tsukuba, Osaka, Kyoto, Shinjuku, Okayama, Kawasaki and Nagoya.The Society also hosted a virtual Early Career Researcher symposium which involved ASB and the University of California Davis. This was chaired by Dr Adam Hill and we refer you to his Commentary where he writes about the challenges and successes of running a virtual meeting “Biophysics in the time of COVID”.The ASB has had a long-standing policy to encourage presentations from early career biophysicists, even as early as PhD students. These young biophysicists prepare carefully and seem to enjoy what can be a terrifying experience. Professor Jamie Vandenberg moderated a session on careers in biophysics where participants discussed the latest technology in ultrasound, the Victor Chang Innovation Centre, strategies for careers outside of traditional biophysics, the importance of scientific communication and advocacy, and the importance intellectual property law, and finally, there were some encouraging words on a career in biophysics from Boris Martinac.Our friends across the “ditch” in New Zealand had a session that discussed calcium imaging in mouse models of disease, the impact fibrosis on Ca signalling, high-content super-resolution microscopy, effects of ryanodine receptor clustering on arrhythmia, the impact of fibrosis on cardiac Ca signalling, how N-glycans affect shear force activation of Na channels, and a fascinating analysis of how insects have managed to adapt their flight muscles to achieve high-frequency flapping flight.The meeting finished with a presentation of the McAuley-Hope prize for a biophysicist who crosses boundaries in biophysics and develops new techniques and methods. It is not always presented but Dr Till Boecking at the University of New South Wales was the well-deserved winner of this much sought-after Prize.     

Impact of Cross-linking and Drying Method on Drug Delivery Performance of Casein–Pectin Microparticles

Pectin is a heteropolysaccharide which has been investigated for the development of colon-specific drug delivery systems. Polymers have been associated with pectin to reduce its aqueous solubility and improve the performance of drug delivery systems. Pectin–casein interaction is widely known in food research, but it has not been fully considered by pharmaceutical scientists. Thus, this study investigated the potential of casein–pectin microparticles as a drug delivery system and clarified the impact of cross-linking and drying methods on the in vitro release of indomethacin (IND) or acetaminophen (PCT) from microparticles. Microparticles were prepared by coacervation and dried by spray or spouted bed methods. Drug recovery, in vitro drug release, size, morphology, and the thermal and diffractometric properties of dried microparticles were determined. Spray-dried non-cross-linked microparticles were able to prolong IND release, and pectin was still degraded by pectinolytic enzymes. On the other hand, glutaraldehyde cross-linking prevented the enzymatic breakdown of pectin without improving IND release. Spouted bed drying reduced IND recovery from all microparticles when compared with spray drying, thus the successful spouted bed drying of microparticles depends on the chemical characteristics of both the drug and the polymer. Release data from PCT microparticles suggested that the microparticle formulation should be improved to bring about a more efficient delivery of water-soluble drugs. In conclusion, casein–pectin microparticles show great potential as a drug delivery system because casein reduces the water solubility of pectin. The drying method and cross-linking process had significant effects on the in vitro performance of these microparticles.     

Interactions and Diffusion in Fine-Stranded β-lactoglobulin Gels Determined via FRAP and Binding

The effects of electrostatic interactions and obstruction by the microstructure on probe diffusion were determined in positively charged hydrogels. Probe diffusion in fine-stranded gels and solutions of β-lactoglobulin at pH 3.5 was determined using fluorescence recovery after photobleaching (FRAP) and binding, which is widely used in biophysics. The microstructures of the β-lactoglobulin gels were characterized using transmission electron microscopy. The effects of probe size and charge (negatively charged Na₂-fluorescein (376Da) and weakly anionic 70kDa FITC-dextran), probe concentration (50 to 200 ppm), and β-lactoglobulin concentration (9% to 12% w/w) on the diffusion properties and the electrostatic interaction between the negatively charged probes and the positively charged gels or solutions were evaluated. The results show that the diffusion of negatively charged Na₂-fluorescein is strongly influenced by electrostatic interactions in the positively charged β-lactoglobulin systems. A linear relationship between the pseudo-on binding rate constant and the β-lactoglobulin concentration for three different probe concentrations was found. This validates an important assumption of existing biophysical FRAP and binding models, namely that the pseudo-on binding rate constant equals the product of the molecular binding rate constant and the concentration of the free binding sites. Indicators were established to clarify whether FRAP data should be analyzed using a binding-diffusion model or an obstruction-diffusion model.     

Ultrasound-Targeted Microbubble Destruction (UTMD) for Localized Drug Delivery into Tumor Tissue

Background

Ultrasound-targeted microbubble destruction (UTMD) is a type of ultrasound therapy, in which low frequency moderate power ultrasound is combined with microbubbles to trigger cavitation. Cavitation is the process of oscillation of gas bubbles causing biophysical effects such as pushing and pulling or shock waves that permeabilize biological barriers. In vivo, cavitation results in tissue permeabilization and is used to enable local delivery of nanomedicine. While cavitation can occur in biological liquids when high pressure ultrasound is applied, the use of microbubbles as cavitation nuclei in UTMD largely facilitates the induction of cavitation. UTMD is intensively studied for drug delivery into tumor tissue, but also for the activation of anti-tumor immune responses. The first clinical studies of UTMD-mediated chemotherapy delivery confirmed safety and efficacy of this approach.

Alternating Magnetic Field-Responsive Hybrid Gelatin Microgels for Controlled Drug Release

Magnetically-responsive nano/micro-engineered biomaterials that enable a tightly controlled, on-demand drug delivery have been developed as new types of smart soft devices for biomedical applications. Although a number of magnetically-responsive drug delivery systems have demonstrated efficacies through either in vitro proof of concept studies or in vivo preclinical applications, their use in clinical settings is still limited by their insufficient biocompatibility or biodegradability. Additionally, many of the existing platforms rely on sophisticated techniques for their fabrications. We recently demonstrated the fabrication of biodegradable, gelatin-based thermo-responsive microgel by physically entrapping poly(N-isopropylacrylamide-co-acrylamide) chains as a minor component within a three-dimensional gelatin network. In this study, we present a facile method to fabricate a biodegradable drug release platform that enables a magneto-thermally triggered drug release. This was achieved by incorporating superparamagnetic iron oxide nanoparticles and thermo-responsive polymers within gelatin-based colloidal microgels, in conjunction with an alternating magnetic field application system.     

The Design of Nanostructured Metronidazole-Loaded HPC/Oxide Xerogel Composites: Influence of the Formulation Parameters on In Vitro Characterisation

In this study, oxide and polymer/oxide xerogels with metronidazole were prepared and examined as carriers of drug for the local application to the bone. The nanoporous SiO₂–CaO–P₂O₅ and HPC–SiO₂–CaO–P₂O₅ xerogel materials with different amounts of the polymer [hydroxypropyl cellulose (HPC)] were prepared using the sol–gel technology, and their physicochemical properties were characterised with respect to chemical structure [by Fourier transform infrared spectroscopy (FTIR)], porosity and the specific surface area of solids (BET), crystallinity [by X-ray powder diffraction (XRD)], morphology [by scanning electron microscope (SEM)] and the in vitro release of the metronidazole over time (by UV–vis spectroscopy, in the ultraviolet light region). HPC-modified oxide xerogels as the carriers of drug showed slower release of metronidazole, due to the structure and stronger interactions with drug as compared with the pure oxide xerogel. Kinetic analysis indicated diffusional mechanism of drug release from all xerogel carriers. HPC addition to the oxide material resulted in a decrease in the porosity and improved the bioactive properties of xerogels. Obtained results for xerogel composites suggest that the metronidazole-loaded xerogels could be attractive candidates for local delivery systems particularly to a bone.KEY WORDS: drug delivery systems, nanostructured composites, porous materials     

Editorial for ‘Issue focus on 2nd Costa Rica biophysics symposium — March 11th–12th, 2021’

This Editorial describes both the motivation for, and the five articles appearing in, the Issue Focus dedicated to the 2nd Costa Rica Biophysics Symposium which was held in March 2021. Some recent history about both the symposium and developments in science occurring within Costa Rica is described. 

The Costa Rica Biophysics Symposium was conceived as a forum for faculty, scholars and students interested on cutting-edge topics in biophysics and related fields. Following the success of the first event organized in 2019 (Solís et al (2020), the second edition of the symposium took place on March 2021 with the support of the Academia Nacional de Ciencias de Costa Rica (ANC, National Academy of Sciences of Costa Rica), the International Union of Pure and Applied Biophysics (IUPAB), the German Society of Biophysics (DGfB), and the Universidad Nacional of Costa Rica (UNA). The symposium aimed to reinforce and enhance the novel network of investigators established in the 2019 event. Participation of Costa Rican presenters, either located in the country or abroad, and foreign scientists from the USA, Germany, France, and Switzerland (Solís et al. (2021a) translated into an expansion and internationalization of the previous network. Moreover, the symposium attracted a broad international audience, which increases the opportunities of further international collaboration.The meeting was organized into 14 presentations and one keynote lecture. It was attended by researchers of the three main universities of Costa Rica: Universidad Nacional (UNA), Universidad de Costa Rica (UCR) and Tecnológico de Costa Rica (TEC). Presenters from international universities were also present, including UT Southwestern Medical Center, USA; Klinikum Nürnberg Medical School, Germany; École Polytechnique Fédérale de Lausanne, Switzerland; Institut de Neurosciences de Montpellier, France; University of California Berkeley, USA; and The University of Chicago, USA. The topics presented in the symposium were diverse and covered cutting-edge biophysical research areas. The presentations ranged from channel electrophysiology, machine learning focused on cellular microscopy, prediction of protein–protein interactions, channelopathies and novel biophysical techniques, among others (Solís et al., 2021a). Furthermore, each lecture was followed by questions from the audience, allowing discussion, engagement and interaction between researchers in spite of the limitations of a virtual symposium. The closing event for the symposium was a lecture by the world-renowned biophysicist Francisco Bezanilla from the University of Chicago, who engaged the audience into a master presentation of his vast research on protein voltage-sensor domains (VSD) with a focus on his recent work on the non-canonical mechanisms for VSD-mediated regulation of pore domains in voltage-gated potassium channels (Carvalho-de-Souza and Bezanilla 2019). After the consequent discussion, the symposium finished with a networking activity, where audience and presenters were able to socialize and share experiences.     

Q & A. [interview

George Oster is Professor of Biophysics, University of California, Berkeley. He received his B.S. at the U.S. Merchant Marine Academy and his Ph.D. at Columbia University. He began his career in biophysics as a postdoc at the Weizmann Institute under Aharon Katchalsky, where his research involved membrane biophysics and irreversible thermodynamics. His concern for environmental issues led him into population biology, which shaded into evolutionary biology and thence to developmental biology, cell biology and, most recently, protein motors and bacterial motility and pattern formation. His tools are mathematics, physics and computer simulation. He is currently a faculty member in the Departments of Molecular and Cellular Biology and the College of Natural Resources at Berkeley.     

Advance and prospect of bionanomaterials

Over the past few years, bionanomaterial science has emerged as a new exciting field in which theoretical and experimental studies of structure and function of bionanomaterials have become a focus, and the importance of DNA, RNA, and peptides as bionanomaterials to the fundamental development in biology and nanomaterials has begun to be recognized. In particular, biochemistry, biophysics, biomechanics, thermodynamics, and electronic properties of DNA, RNA, and peptides, as well as intelligent composite biological materials, have become a new interdisciplinary frontier in life science and material science. There is an increasing need for a more systematic study of the basic issues involved in bionanomaterials and a more active participation of researchers in the application domain of such novel materials. Great advances have been and are being made in nanobiochip materials, nanoscale biomimetic materials, nanomotors, nanocomposite materials, interface biomaterials, and nanobiosensor and nano drug delivery systems, with enormous prospect in industrial, defense, and clinical medicine applications. Here we review some of the main advances in this field over the past few years, explore the application prospects, and discuss the concepts, issues, approaches, and challenges, with the aim of stimulating a broader interest in developing bionanomaterials technology.     

Genetic Variation of the Ghrelin Signalling System in Individuals with Amphetamine Dependence

The development of amphetamine dependence largely depends on the effects of amphetamine in the brain reward systems. Ghrelin, an orexigenic peptide, activates the reward systems and is required for reward induced by alcohol, nicotine, cocaine and amphetamine in mice. Human genetic studies have shown that polymorphisms in the pre-proghrelin (GHRL) as well as GHS-R1A (GHSR) genes are associated with high alcohol consumption, increased weight and smoking in males. Since the heritability factor underlying drug dependence is shared between different drugs of abuse, we here examine the association between single nucleotide polymorphisms (SNPs) and haplotypes in the GHRL and GHSR, and amphetamine dependence. GHRL and GHSR SNPs were genotyped in Swedish amphetamine dependent individuals (n = 104) and controls from the general population (n = 310). A case-control analysis was performed and SNPs and haplotypes were additionally tested for association against Addiction Severity Interview (ASI) composite score of drug use. The minor G-allele of the GHSR SNP rs2948694, was more common among amphetamine dependent individuals when compared to controls (p_c = 0.02). A significant association between the GHRL SNP rs4684677 and ASI composite score of drug use was also reported (p_c = 0.03). The haplotype analysis did not add to the information given by the individual polymorphisms. Although genetic variability of the ghrelin signalling system is not a diagnostic marker for amphetamine dependence and problem severity of drug use, the present results strengthen the notion that ghrelin and its receptor may be involved in the development of addictive behaviours and may thus serve as suitable targets for new treatments of such disorders.     

Selective Interactions of Zein Microspheres with Different Class of Drugs: An In Vitro and In Silico Analysis

In this study, we have evaluated the interactions of zein microspheres with different class of drugs (hydrophobic, hydrophilic, and amphiphilic) using in vitro and in silico analysis. Zein microspheres loaded with aceclofenac, metformin, and promethazine has been developed by solvent evaporation technique and analyzed for its compatibility. The physical characterization depicted the proper encapsulation of hydrophobic drug in the microspheres. The in vitro release study revealed the sustaining ability of the microspheres in the following order: hydrophobic > hydrophilic > amphiphilic. In silico analysis also confirmed the better binding affinity and greater interactions of hydrophobic drug with zein. The above results revealed that zein is more suitable for hydrophobic drugs in the development of sustained drug delivery systems using solvent evaporation technique. The study therefore envisages a scope for identifying the most suitable polymer for a sustained drug delivery system in accordance with the nature of the drug.KEY WORDS: hydrophilic drugs, hydrophobic drugs, in silico analysis, protein-drug interactions, solvent evaporation, zein microspheres     

Designing Silk-silk Protein Alloy Materials for Biomedical Applications

Fibrous proteins display different sequences and structures that have been used for various applications in biomedical fields such as biosensors, nanomedicine, tissue regeneration, and drug delivery. Designing materials based on the molecular-scale interactions between these proteins will help generate new multifunctional protein alloy biomaterials with tunable properties. Such alloy material systems also provide advantages in comparison to traditional synthetic polymers due to the materials biodegradability, biocompatibility, and tenability in the body. This article used the protein blends of wild tussah silk (Antheraea pernyi) and domestic mulberry silk (Bombyx mori) as an example to provide useful protocols regarding these topics, including how to predict protein-protein interactions by computational methods, how to produce protein alloy solutions, how to verify alloy systems by thermal analysis, and how to fabricate variable alloy materials including optical materials with diffraction gratings, electric materials with circuits coatings, and pharmaceutical materials for drug release and delivery. These methods can provide important information for designing the next generation multifunctional biomaterials based on different protein alloys.     

Interactions of cisplatin analogues with lysozyme: a comparative analysis

The biophysical characterization of drug binding to proteins plays a key role in structural biology and in the discovery and optimization of drug discovery processes. The search for optimal combinations of biophysical techniques that can correctly and efficiently identify and quantify binding of metal-based drugs to their final target is challenging, due to the physicochemical properties of these agents. Different cisplatin derivatives have shown different citotoxicities in most common cancer lines, suggesting that they exert their biological activity via different mechanisms of action. Here we carried out a comparative analysis, by studying the behaviours of three Pt-compounds under the same experimental conditions and binding assays to properly deepen the determinants of the different MAOs. Indeed we compared the results obtained using surface plasmon resonance, isothermal titration calorimetry, fluorescence spectroscopy and thermal shift assays based on circular dichroism experiments in the characterization of the formation of adducts obtained upon reaction of cisplatin, carboplatin and iodinated analogue of cisplatin, cis-Pt (NH₃)₂I₂, with the model protein hen egg white lysozyme, both at neutral and acid pHs. Further we reasoned on the applicability of employed techniques for the study the thermodynamics and kinetics of the reaction of a metallodrug with a protein and to reveal which information can be obtained using a combination of these analyses. Data were discussed on the light of the existing structural data collected on the platinated protein.     

Ultrasound-induced biophysical effects in controlled drug delivery

Ultrasound is widely used in biomedical engineering and has applications in conventional diagnosis and drug delivery. Recent advances in ultrasound-induced drug delivery have been summarized previously in several reviews that have primarily focused on the fabrication of drug delivery carriers. This review discusses the mechanisms underlying ultrasound-induced drug delivery and factors affecting delivery efficiency, including the characteristics of drug delivery carriers and ultrasound parameters. Firstly, biophysical effects induced by ultrasound, namely thermal effects, cavitation effects, and acoustic radiation forces, are illustrated. Secondly, the use of these biophysical effects to enhance drug delivery by affecting drug carriers and corresponding tissues is clarified in detail. Thirdly, recent advances in ultrasound-triggered drug delivery are detailed. Safety issues and optimization strategies to improve therapeutic outcomes and reduce side effects are summarized. Finally, current progress and future directions are discussed.

     

Biocompatible, biodegradable and thermo-sensitive chitosan-g-poly (N-isopropylacrylamide) nanocarrier for curcumin drug delivery

A nano formulation of curcumin loaded biodegradable thermoresponsive chitosan-g-poly (N-isopropylacrylamide) co-polymeric nanoparticles (TRC-NPs) (150 nm) were prepared by ionic cross-linking method and characterized. The in vitro drug release was prominent at above LCST. Cytocompatibility of TRC-NPs (100-1000 μg/ml) on an array of cell line is proved by MTT assay. The drug loaded TRC-NPs showed specific toxicity on cancer cells. The cell uptake studies were confirmed by fluorescent microscopy. Flowcytometric analysis of curcumin loaded TRC-NPs showed increased apoptosis on PC3 cells. These results indicated that TRC-NPs could be a potential nanovehicle for curcumin drug delivery.     

Polymeric Micelles for Multi-Drug Delivery in Cancer

Drug combinations are common in cancer treatment and are rapidly evolving, moving beyond chemotherapy combinations to combinations of signal transduction inhibitors. For the delivery of drug combinations, i.e., multi-drug delivery, major considerations are synergy, dose regimen (concurrent versus sequential), pharmacokinetics, toxicity, and safety. In this contribution, we review recent research on polymeric micelles for multi-drug delivery in cancer. In concurrent drug delivery, polymeric micelles deliver multi-poorly water-soluble anticancer agents, satisfying strict requirements in solubility, stability, and safety. In sequential drug delivery, polymeric micelles participate in pretreatment strategies that “prime” solid tumors and enhance the penetration of secondarily administered anticancer agent or nanocarrier. The improved delivery of multiple poorly water-soluble anticancer agents by polymeric micelles via concurrent or sequential regimens offers novel and interesting strategies for drug combinations in cancer treatment.KEY WORDS: controlled release, drug combination, drug delivery, drug solubilization, polymeric micelles     

Bacterial components as naturally inspired nano-carriers for drug/gene delivery and immunization: Set the bugs to work?

Drug delivery is a rapidly growing area of research motivated by the nanotechnology revolution, the ideal of personalized medicine, and the desire to reduce the side effects of toxic anti-cancer drugs. Amongst a bewildering array of different nanostructures and nanocarriers, those examples that are fundamentally bio-inspired and derived from natural sources are particularly preferred. Delivery of vaccines is also an active area of research in this field. Bacterial cells and their components that have been used for drug delivery, include the crystalline cell-surface layer known as “S-layer”, bacterial ghosts, bacterial outer membrane vesicles, and bacterial products or derivatives (e.g. spores, polymers, and magnetic nanoparticles). Considering the origin of these components from potentially pathogenic microorganisms, it is not surprising that they have been applied for vaccines and immunization. The present review critically summarizes their applications focusing on their advantages for delivery of drugs, genes, and vaccines.     

我国生物物理学的奠基与交叉学科的建立

20世纪50年代上半叶,生物物理学作为一门新的独立学科应运而生.1958年,以中国科学院生物物理研究所的成立为主要标志,开始了我国生物物理学的发展历程.本文将介绍我国生物物理学科的奠基与前期发展,以及放射生物学、生物控制论、宇宙生物学和仿生学等交叉学科的建立过程.