Target-Triggered Formation of Artificial Enzymes on Filamentous Phage for Ultrasensitive Direct Detection of Circulating miRNA Biomarkers in Clinical Samples.

Integrating artificial enzymes onto nanostructures target- and site-specifically is still a challenge. Here we show that target miRNAs trigger the formation of DNAzyme site-specifically at the tip of filamentous phage for detecting miRNA biomarkers. Through an antibody-modified oligonucleotide, the tip of the phage with magnetic nanoparticles on the sidewall captures a target miRNA, inducing the formation of DNAzyme that extends from the phage tip through a hybridization chain reaction.

Selectively Suppressing Tumor Angiogenesis for Targeted Breast Cancer Therapy by Genetically Engineered Phage.

Antiangiogenesis is a promising approach to cancer therapy but is limited by the lack of tumor-homing capability of the current antiangiogenic agents. Angiogenin, a protein overexpressed and secreted by tumors to trigger angiogenesis for their growth, has never been explored as an antiangiogenic target in cancer therapy. Here it is shown that filamentous fd phage, as a biomolecular biocompatible nanofiber, can be engineered to become capable of first homing to orthotopic breast tumors and then capturing angiogenin to prevent tumor angiogenesis, resulting in targeted cancer therapy without side effects.

Phage nanofibers in nanomedicine: Biopanning for early diagnosis, targeted therapy, and proteomics analysis.

Display of a peptide or protein of interest on the filamentous phage (also known as bacteriophage), a biological nanofiber, has opened a new route for disease diagnosis and therapy as well as proteomics. Earlier phage display was widely used in protein-protein or antigen-antibody studies. In recent years, its application in nanomedicine is becoming increasingly popular and encouraging.

Hierarchical Ordered Assembly of Genetically Modifiable Viruses into Nanoridge-in-Microridge Structures.

Hierarchically assembled nanomaterials can find a variety of applications in medicine, energy, and electronics. Here, an automatically controlled dip-pulling method is developed and optimized to generate an unprecedented ordered nano-to-micro hierarchical nanoridge-in-microridge (NiM) structure from a bacteria-specific human-safe virus, the filamentous phage with or without genetically displaying a foreign peptide. The NiM structure is pictured as a window blind with each lath (the microridge) made of parallel phage bundles (the nanoridges).

Bacteriophage-based biomaterials for tissue regeneration.

Bacteriophage, also called phage, is a human-safe bacteria-specific virus. It is a monodisperse biological nanostructure made of proteins (forming the outside surface) and nucleic acids (encased in the protein capsid). Among different types of phages, filamentous phages have received great attention in tissue regeneration research due to their unique nanofiber-like morphology.

Virus-Based Cancer Therapeutics for Targeted Photodynamic Therapy.

Cancer photodynamic therapy (PDT) involves the absorption of light by photosensitizers (PSs) to generate cytotoxic singlet oxygen for killing cancer cells. The success of this method is usually limited by the lack of selective accumulation of the PS at cancer cells. Bioengineered viruses with cancer cell-targeting peptides fused on their surfaces are great drug carriers that can guide the PS to cancer cells for targeted cancer treatment.

Identification of Novel Short BaTiO-Binding/Nucleating Peptides for Phage-Templated in Situ Synthesis of BaTiO Polycrystalline Nanowires at Room Temperature.

Ferroelectric materials, such as tetragonal barium titanate (BaTiO), have been widely used in a variety of areas including bioimaging, biosensing, and high power switching devices. However, conventional methods for the synthesis of tetragonal phase BaTiO usually require toxic organic reagents and high temperature treatments, and are thus not environment-friendly and energy-efficient. Here, we took advantage of the phage display technique to develop a novel strategy for the synthesis of BaTiO nanowires.

Cell-Specific Promoters Enable Lipid-Based Nanoparticles to Deliver Genes to Specific Cells of the Retina In Vivo.

Non-viral vectors, such as lipid-based nanoparticles (liposome-protamine-DNA complex [LPD]), could be used to deliver a functional gene to the retina to correct visual function and treat blindness. However, one of the limitations of LPD is the lack of cell specificity, as the retina is composed of seven types of cells. If the same gene is expressed in multiple cell types or is absent from one desired cell type, LPD-mediated gene delivery to every cell may have off-target effects.

Phage as a Genetically Modifiable Supramacromolecule in Chemistry, Materials and Medicine.

Filamentous bacteriophage (phage) is a genetically modifiable supramacromolecule. It can be pictured as a semiflexible nanofiber (∼900 nm long and ∼8 nm wide) made of a DNA core and a protein shell with the former genetically encoding the latter. Although phage bioengineering and phage display techniques were developed before the 1990s, these techniques have not been widely used for chemistry, materials, and biomedical research from the perspective of supramolecular chemistry until recently.

Genetically Engineered Virus Nanofibers as an Efficient Vaccine for Preventing Fungal Infection.

Candida albicans (CA) is a kind of fungus that can cause high morbidity and mortality in immunocompromised patients. However, preventing CA infection in these patients is still a daunting challenge. Herein, inspired from the fact that immunization with secreted aspartyl proteinases 2 (Sap2) can prevent the infection, it is proposed to use filamentous phage, a human-safe virus nanofiber specifically infecting bacteria (≈900 nm long and 7 nm wide), to display an epitope peptide of Sap2 (EPS, with a sequence of Val-Lys-Tyr-Thr-Ser) on its side wall and thus serve as a vaccine for preventing CA infection.

"Cleaning" the Surface of Hydroxyapatite Nanorods by a Reaction-Dissolution Approach.

Synthetic nanoparticles are always terminated with coating molecules, which are often cytotoxic and not desired in biomedicine. Here we propose a novel reaction-dissolution approach to remove the cytotoxic coating molecules. A two-component solution is added to the nanoparticle solution; one component reacts with the coating molecules to form a salt whereas another is a solvent for dissolving and thus removing the salt.

Ultrasensitive rapid detection of human serum antibody biomarkers by biomarker-capturing viral nanofibers.

Candida albicans (C. albicans) infection causes high mortality rates within cancer patients. Due to the low sensitivity of the current diagnosis systems, a new sensitive detection method is needed for its diagnosis.

Stem cells loaded with nanoparticles as a drug carrier for in vivo breast cancer therapy.

A novel anti-cancer drug carrier, mesenchymal stem cells (MSCs) encapsulating drug-loaded hollow silica nanoparticles, is used to carry a photosensitizer drug and deliver it to breast tumors, due to the natural high tumor affinity of the MSCs, and inhibit tumor growth by photo dynamic therapy. This new strategy for delivering a photo sensitizer to tumors by using tumor-affinitive MSCs addresses the challenge of the accumulation of photosensitizer drugs in tumors in photodynamic therapy.

Phage as a template to grow bone mineral nanocrystals.

Phage display is a biotechnique that fuses functional peptides on the outer surface of filamentous phage by inserting DNA encoding the peptides into the genes of its coat proteins. The resultant peptide-displayed phage particles have been widely used as biotemplates for the synthesis of functional hybrid nanomaterials. Here, we describe the bioengineering of M13 filamentous phage to surface-display bone mineral (hydroxyapatite (HAP))-nucleating peptides derived from dentin matrix protein-1 and using the engineered phage as a biotemplate to grow HAP nanocrystals.

Controlled alignment of filamentous supramolecular assemblies of biomolecules into centimeter-scale highly ordered patterns by using nature-inspired magnetic guidance.

We took the advantage of the capability of magnetic nanoparticles (MNPs) being aligned along a magnetic field and reproducibly generated large scale bio-nanofiber assemblies with the orientation of the constituent bio-nanofibers defined by the applied magnetic field. When decorated by MNPs, bio-nanofibers could be guided by the external magnetic field to become oriented either horizontally or vertically, forming single- and multi-orientation layered assemblies.

Mesoporous iron oxide nanoparticles prepared by polyacrylic acid etching and their application in gene delivery to mesenchymal stem cells.

Novel monodisperse mesoporous iron oxide nanoparticles (m-IONPs) were synthesized by a postsynthesis etching approach and characterized by electron microscopy. In this approach, solid iron oxide nanoparticles (s-IONPs) were first prepared following a solvothermal method, and then etched anisotropically by polyacrylic acid to form the mesoporous nanostructures. MTT cytotoxicity assay demonstrated that the m-IONPs have good biocompatibility with mesenchymal stem cells (MSCs).

Virus-based photo-responsive nanowires formed by linking site-directed mutagenesis and chemical reaction.

Owing to the genetic flexibility and error-free bulk production, bio-nanostructures such as filamentous phage showed great potential in materials synthesis, however, their photo-responsive behaviour is neither explored nor unveiled. Here we show M13 phage genetically engineered with tyrosine residues precisely fused to the major coat protein is converted into a photo-responsive organic nanowire by a site-specific chemical reaction with an aromatic amine to form an azo dye structure on the surface. The resulting azo-M13-phage nanowire exhibits reversible photo-responsive properties due to the photo-switchable cis-trans isomerisation of the azo unit formed on the phage.

Oxide Formation on Biological Nanostructures via a Structure-Directing Agent: Towards an Understanding of Precise Structural Transcription.

Biomimetic silica formation is strongly dependent on the presence of cationic amine groups which hydrolyze organosilicate precursors and bind to silicate oligomers. Since most biological species possess anionic surfaces, the dependence on amine groups limits utilization of biotemplates for fabricating materials with specific morphologies and pore structures. Here, we report a general aminopropyltriethoxysilane (APTES) directed method for preparing hollow silica with well-defined morphologies using varying biotemplates (proteins, viruses, flagella, bacteria and fungi).

Controlling nanostructures of mesoporous silica fibers by supramolecular assembly of genetically modifiable bacteriophages.

A useful virus: The synthesis of a new family of mesoporous silica fibers is reported. Monodisperse filamentous bacteriophages self-assembled into highly ordered hexagonal lattices that were used as templates for the formation of silica nanostructures. Removal of the bacteriophage assembly through calcination led to the formation of mesoporous silica fibers with pore structures precisely defined by the bacteriophage assembly (see picture).

Transmission electron microscopy as a tool to image bioinorganic nanohybrids: the case of phage-gold nanocomposites.

In recent years, bioinorganic nanohybrids composed of biological macromolecules and functional inorganic nanomaterials have revealed many unique properties that show promise for the future. Transmission electron microscopy (TEM) is a popular and relatively simple tool that can offer a direct visualization of the nanomaterials with high resolutions. When TEM is applied to visualize bioinorganic nanohybrids, a treatment of negative staining is necessary due to the presence of biological molecules in the nanohybrids except for those with densely packed inorganic materials.

Controlled self-assembly of rodlike bacterial pili particles into ordered lattices.

[Image: see text] Rodlike type 1 bacterial pili particles (see picture, red) self-assemble into highly ordered nanostructures through molecular recognition in the presence of suitable inducers. 1D bundles, 2D double-layer lattices, and 3D multilayer lattices were produced by varying the nature and concentration of the inducers. The self-assembled pili serve as templates for nucleating and organizing inorganic nanomaterials such as silica.

Self-assembly and mineralization of genetically modifiable biological nanofibers driven by β-structure formation.

Bioinspired mineralization is an innovative approach to the fabrication of bone biomaterials mimicking the natural bone. Bone mineral hydroxylapatite (HAP) is preferentially oriented with c-axis parallel to collagen fibers in natural bone. However, such orientation control is not easy to achieve in artificial bone biomaterials.

Controlled growth and differentiation of MSCs on grooved films assembled from monodisperse biological nanofibers with genetically tunable surface chemistries.

The search for a cell-supporting scaffold with controlled topography and surface chemistry is a constant topic within tissue engineering. Here we have employed M13 phages, which are genetically modifiable biological nanofibers (∼ 880 nm long and ∼ 6.6 nm wide) non-toxic to human beings, to form films for supporting the growth of mesencymal stem cells (MSCs).

Bacteriophage Bundles with Pre-Aligned Ca Initiate the Oriented Nucleation and Growth of Hydroxylapatite.

Inorganic ions may direct the self-assembly of biomacromolecules into nanostructures which can further be used as a reactant and matrix for nanomaterials synthesis and assembly. Here we use bone mineral and filamentous bacteriophage as a model to demonstrate this concept. Divalent calcium ions are found to trigger the electrostatic self-assembly of anionic nanofiber-like bacteriophages into bundle structures where calcium ions are pre-organized between bacteriophage nanofibers.