Biomedical subjects

Angela M Belcher

Publications and source records attributed to Angela M Belcher.

13 recordsLinked to original sources

PubMed2025

A Programmable Nanovaccine Platform Based on M13 Bacteriophage for Personalized Cancer Vaccine and Therapy.

Nanovaccines co-assemble antigens and adjuvants to elicit robust immune responses but often require complex synthesis and post-modification procedures. Here, a programmable nanovaccine platform based on the M13 bacteriophage is developed for the scalable production of vaccines and single-step modular engineering of adjuvanticity, length, and antigen density. By reprogramming the sequence and size of the noncoding phage genome, the Toll-like receptor 9 activation and the length of the phage are precisely controlled. With a novel molecular engineering approach, the antigen density is tuned from 13.6% to 70.3%. A systematic modulation reveals an optimal adjuvanticity at a constant antigen density for maximum anti-tumor CD8+ T cell response, and vice versa, using the model antigen SIINFEKL. The M13 phage-based nanovaccine induces durable memory immunity lasting over a year. In addition, a 24-fold increase in neoantigen-specific CD8+ T cell frequency is achieved when increasing both the adjuvanticity and antigen density. Furthermore, when combined with anti-PD-1 therapy, the M13 phage-based personalized vaccine eradicates established MC-38 tumors in 75% of treated animals and they develop 100% resistance against tumor invasion when challenged 5 months after treatment. These findings establish M13 phage as a powerful and versatile nanovaccine platform with transformative potential for personalized cancer immunotherapy.

Cancer Vaccines↗

PubMed2006

Virus-enabled synthesis and assembly of nanowires for lithium ion battery electrodes.

The selection and assembly of materials are central issues in the development of smaller, more flexible batteries. Cobalt oxide has shown excellent electrochemical cycling properties and is thus under consideration as an electrode for advanced lithium batteries. We used viruses to synthesize and assemble nanowires of cobalt oxide at room temperature. By incorporating gold-binding peptides into the filament coat, we formed hybrid gold-cobalt oxide wires that improved battery capacity. Combining virus-templated synthesis at the peptide level and methods for controlling two-dimensional assembly of viruses on polyelectrolyte multilayers provides a systematic platform for integrating these nanomaterials to form thin, flexible lithium ion batteries.

Bacteriophage M13↗

PubMed2006

Spontaneous assembly of viruses on multilayered polymer surfaces.

The idea that randomly arranged supermolecular species incorporated in a network medium can ultimately create ordered structures at the surface may be counterintuitive. However, such order can be accommodated by regulating dynamic and equilibrium driving forces. Here, we present the ordering of M13 viruses, highly complex biomacromolecules, driven by competitive electrostatic binding, preferential macromolecular interactions and the rigid-rod nature of the virus systems during alternating electrostatic assembly. The steric constraints inherent to the competitive charge binding between M13 viruses and two oppositely charged weak polyelectrolytes leads to interdiffusion and the virtual 'floating' of viruses to the surface. The result is the spontaneous formation of a two-dimensional monolayer structure of viruses atop a cohesive polyelectrolyte multilayer. We demonstrate that this viral-assembled monolayer can be a biologically tunable scaffold to nucleate, grow and align nanoparticles or nanowires over multiple length scales. This system represents an interface that provides a general platform for the systematic incorporation and assembly of organic, biological and inorganic materials.

Acrylic Resins↗

PubMed2006

Cobalt ion mediated self-assembly of genetically engineered bacteriophage for biomimetic Co-Pt hybrid material.

Biological scaffolds are used for the synthesis of inorganic materials due to their ability to self-assemble and nucleate crystal formation. We report the self-assembly of engineered M13 bacteriophage as a template for Co-Pt crystals. A M13 phage library with an octapeptide library on the major coat protein (pVIII) was used for selection of binders to cobalt ions. Fibrous structures with directionally ordered M13 phage were obtained by interaction with cobalt ions. Co-Pt alloys were synthesized on the fibrous scaffold, and their magnetic properties were characterized. The mineralization showed organized nanoparticles on fibrous bundles. This approach using the phage pVIII library allows for genetic selection that both induces assembly of the phage and directs mineralization of the selected inorganic material.

Bacteriophage M13↗

PubMed2005

Design criteria for engineering inorganic material-specific peptides.

Development of a fundamental understanding of how peptides specifically interact with inorganic material surfaces is crucial to furthering many applications in the field of nanobiotechnology. Herein, we report systematic study of peptide sequence-activity relationships for binding to II-VI semiconductors (CdS, CdSe, ZnS, ZnSe) and Au using a yeast surface display system, and we define criteria for tuning peptide affinity and specificity for these material surfaces. First, homohexapeptides of the 20 naturally occurring amino acids were engineered, expressed on yeast surface, and assayed for the ability to bind each material surface in order to define functional groups sufficient for binding. Histidine (H6) was able to mediate binding of yeast to the five materials studied, while tryptophan (W6), cysteine (C6), and methionine (M6) exhibited different levels of binding to single-crystalline ZnS and ZnSe and polycrystalline Au surfaces. The ability of neighboring amino acids to up- and down-modulate histidine binding was then evaluated by use of interdigitated peptides (XHXHXHX). While the 20 amino acids exhibited a unique fingerprint of modulation for each material, some general trends emerged. With neutral defined by alanine, up-modulation occurred with glycine, basic amino acids, and the previously defined binding amino acids histidine, tryptophan, cysteine, and methionine, and down-modulation generally occurred with acidic, polar, and hydrophobic residues. We conclude that certain amino acids directly bind the material surface while neighboring amino acids locally modulate the binding environment for the materials we studied. Therefore, by the specific placement of up- and down-modulating amino acids, material specificity can be controlled. Finally, by employing the compositional and spatial criteria developed herein, it was possible to predictively design peptide sequences with material specificity, including a multimaterial binder, a Au-specific binder, and a ZnS-specific binder, that were verified as such in the context of yeast display.

Amino Acid Sequence↗

PubMed2005

Biomaterials functionalization using a novel peptide that selectively binds to a conducting polymer.

The goal in biomaterial surface modification is to retain a material's bulk properties while modifying only its surface to possess desired recognition and specificity. Here we develop a unique strategy for surface functionalization of an electrically conductive polymer, chlorine-doped polypyrrole (PPyCl), which has been widely researched for various electronic and biomedical applications. An M13 bacteriophage library was used to screen 10(9) different 12-mer peptide inserts against PPyCl. A binding phage (phiT59) was isolated, and its binding stability and specificity to PPyCl was assessed using fluorescence microscopy and titer count analysis. The relative binding strength and mechanism of the corresponding 12-mer peptide and its variants was studied using atomic force microscopy and fluorescamine assays. Further, the T59 peptide was joined to a cell adhesive sequence and used to promote cell attachment on PPyCl. This strategy can be extended to immobilize a variety of molecules to PPyCl for numerous applications. In addition, phage display can be applied to other polymers to develop bioactive materials without altering their bulk properties.

Adsorption↗

PubMed2005

Probing the interface between biomolecules and inorganic materials using yeast surface display and genetic engineering.

Although promising for biomimetic materials applications, polypeptides binding inorganic material surfaces and the mechanism of their function have been difficult to characterize. This paper reports sequence-activity relationships of peptides interfacing with semiconductor CdS, and presents methodologies broadly applicable to studying peptide-solid surface interactions. We first employed yeast surface display with a human repertoire antibody library and identified rarely-occurring scFv fragments as CdS-binding polypeptides. Using our semi-quantitative cell-surface binding assay, site-directed mutational analysis, and genetic engineering we defined short distal regions of the displayed polypeptides necessary and sufficient for CdS binding. Alanine scanning mutagenesis in combination with a series of engineered polyhistidine peptides elucidated a direct relationship between histidine number and binding strength, which appeared to be further modulated by arginine and basic residues. The minimum strength of interaction was established by competition studies using soluble synthetic peptide analogs, which showed half-maximal inhibition of yeast binding to CdS at approximately 2 microM peptide. We then showed the ability of cells displaying material-specific polypeptides to form self-healing biofilms and discriminate between materials of fabricated heterostructure surfaces. Furthermore, we demonstrated the synthetic potential of the selected soluble CdS peptide in mediating aqueous synthesis of fluorescent CdS nanoparticles at room temperature. This platform may be further applied to elucidate mechanisms governing interfacial interactions and to generate material-specific reagents useful in medicine, biosensors, and bioproduction of high value inorganic materials.

Amino Acid Sequence↗

PubMed2005

Programmable assembly of nanoarchitectures using genetically engineered viruses.

Biological systems possess inherent molecular recognition and self-assembly capabilities and are attractive templates for constructing complex material structures with molecular precision. Here we report the assembly of various nanoachitectures including nanoparticle arrays, hetero-nanoparticle architectures, and nanowires utilizing highly engineered M13 bacteriophage as templates. The genome of M13 phage can be rationally engineered to produce viral particles with distinct substrate-specific peptides expressed on the filamentous capsid and the ends, providing a generic template for programmable assembly of complex nanostructures. Phage clones with gold-binding motifs on the capsid and streptavidin-binding motifs at one end are created and used to assemble Au and CdSe nanocrytals into ordered one-dimensional arrays and more complex geometries. Initial studies show such nanoparticle arrays can further function as templates to nucleate highly conductive nanowires that are important for addressing/interconnecting individual nanostructures.

Bacteriophage M13↗

PubMed2004

Virus-based toolkit for the directed synthesis of magnetic and semiconducting nanowires.

We report a virus-based scaffold for the synthesis of single-crystal ZnS, CdS, and freestanding chemically ordered CoPt and FePt nanowires, with the means of modifying substrate specificity through standard biological methods. Peptides (selected through an evolutionary screening process) that exhibit control of composition, size, and phase during nanoparticle nucleation have been expressed on the highly ordered filamentous capsid of the M13 bacteriophage. The incorporation of specific, nucleating peptides into the generic scaffold of the M13 coat structure provides a viable template for the directed synthesis of semiconducting and magnetic materials. Removal of the viral template by means of annealing promoted oriented aggregation-based crystal growth, forming individual crystalline nanowires. The unique ability to interchange substrate-specific peptides into the linear self-assembled filamentous construct of the M13 virus introduces a material tunability that has not been seen in previous synthetic routes. Therefore, this system provides a genetic toolkit for growing and organizing nanowires from semiconducting and magnetic materials.

Alloys↗

PubMed2004

Bacterial biosynthesis of cadmium sulfide nanocrystals.

Semiconductor nanocrystals, which have unique optical and electronic properties, have potential for applications in the emerging field of nanoelectronics. To produce nanocrystals cheaply and efficiently, biological methods of synthesis are being explored. We found that E. coli, when incubated with cadmium chloride and sodium sulfide, have the capacity to synthesize intracellular cadmium sulfide (CdS) nanocrystals. The nanocrystals are composed of a wurtzite crystal phase with a size distribution of 2-5 nm. Nanocrystal biosynthesis increased about 20-fold in E. coli cells grown to stationary phase compared to late logarithmic phase. Our results highlight how different genetic and physiological parameters can enhance the formation of nanocrystals within bacterial cells.

Cadmium Compounds↗

PubMed2003

Viral assembly of oriented quantum dot nanowires.

The highly organized structure of M13 bacteriophage was used as an evolved biological template for the nucleation and orientation of semiconductor nanowires. To create this organized template, peptides were selected by using a pIII phage display library for their ability to nucleate ZnS or CdS nanocrystals. The successful peptides were expressed as pVIII fusion proteins into the crystalline capsid of the virus. The engineered viruses were exposed to semiconductor precursor solutions, and the resultant nanocrystals that were templated along the viruses to form nanowires were extensively characterized by using high-resolution analytical electron microscopy and photoluminescence. ZnS nanocrystals were well crystallized on the viral capsid in a hexagonal wurtzite or a cubic zinc blende structure, depending on the peptide expressed on the viral capsid. Electron diffraction patterns showed single-crystal type behavior from a polynanocrystalline area of the nanowire formed, suggesting that the nanocrystals on the virus were preferentially oriented with their [001] perpendicular to the viral surface. Peptides that specifically directed CdS nanocrystal growth were also engineered into the viral capsid to create wurtzite CdS virus-based nanowires. Lastly, heterostructured nucleation was achieved with a dual-peptide virus engineered to express two distinct peptides within the same viral capsid. This work represents a genetically controlled biological synthesis route to a semiconductor nanoscale heterostructure.

Bacteriophage M13↗

PubMed2002

Ordering of quantum dots using genetically engineered viruses.

A liquid crystal system was used for the fabrication of a highly ordered composite material from genetically engineered M13 bacteriophage and zinc sulfide (ZnS) nanocrystals. The bacteriophage, which formed the basis of the self-ordering system, were selected to have a specific recognition moiety for ZnS crystal surfaces. The bacteriophage were coupled with ZnS solution precursors and spontaneously evolved a self-supporting hybrid film material that was ordered at the nanoscale and at the micrometer scale into approximately 72-micrometer domains, which were continuous over a centimeter length scale. In addition, suspensions were prepared in which the lyotropic liquid crystalline phase behavior of the hybrid material was controlled by solvent concentration and by the use of a magnetic field.

Bacteriophage M13↗

PubMed2002

Emulating biology: building nanostructures from the bottom up.

The biological approach to nanotechnology has produced self-assembled objects, arrays and devices; likewise, it has achieved the recognition of inorganic systems and the control of their growth. Can these approaches now be integrated to produce useful systems?

DNA↗