Synthetic Biogenesis of Bacterial Amyloid Nanomaterials with Tunable Inorganic-Organic Interfaces and Electrical Conductivity

Amyloids are highly ordered, hierarchal protein nanoassemblies. Functional amyloids in bacterial biofilms, such as Escherichia coli curli fibers, are formed by the polymerization of monomeric proteins secreted into the extracellular space. Curli is synthesized by living cells, is primarily composed of the major curlin subunit CsgA, and forms biological nanofibers with high aspect ratios. Here, we explore the application of curli fibers for nanotechnology by engineering curli to mediate tunable biological interfaces with inorganic materials and to controllably form gold nanoparticles and gold nanowires. Specifically, we used cell-synthesized curli fibers as templates for nucleating and growing gold nanoparticles and showed that nanoparticle size could be modulated as a function of curli fiber gold-binding affinity. Furthermore, we demonstrated that gold nanoparticles can be preseeded onto curli fibers and followed by gold enhancement to form nanowires. Using these two approaches, we created artificial cellular systems that integrate inorganic-organic materials to achieve tunable electrical conductivity. We envision that cell-synthesized amyloid nanofibers will be useful for interfacing abiotic and biotic systems to create living functional materials.. © 2016 American Chemical Society

Multi-level outcomes for young adults with acquired brain injury through a remote intensive cognitive rehabilitation approach: a pilot intervention study

OBJECTIVE: To investigate the effects of the Intensive Cognitive and Communication Rehabilitation (ICCR) program for young adults with acquired brain injury (ABI) using a quasi-experimental pilot intervention study design while transitioning to remote implementation. METHOD: Twelve young adults with chronic ABI (treatment n = 7; control n = 5) participated in ICCR (i.e., lectures, seminars, individual cognitive rehabilitation (CR), technology training) for six hours/day, four days/week, for one or two 12-week semesters. Outcomes included classroom metrics, individual therapy performance, including Goal Attainment Scaling (GAS), standardized cognitive-linguistic assessments, and participation and health-related quality of life (QOL) measures. RESULTS: In the first semester (in-person and remote), treatment participants significantly improved in classroom exams; individual therapy (i.e., memory, writing, GAS); executive function and participation measures, but not QOL. In the second semester (remote), treatment participants significantly improved in classroom exams; essay writing; individual therapy (i.e., writing and GAS); and memory assessment, but not in participation or QOL. Treatment participants enrolled in consecutive semesters significantly improved in classroom exams, individual therapy (i.e., memory), participation and QOL, but not on standardized cognitive assessments. Controls demonstrated no significant group-level gains. CONCLUSION: These preliminary results highlight the benefit of intensive, integrated, and contextualized CR for this population and show promise for its remote delivery.F31 DC017892 - NIDCD NIH HHSAccepted manuscrip

Synthesis and patterning of tunable multiscale materials with engineered cells

Many natural biological systems - such as biofilms, shells and skeletal tissues - are able to assemble multifunctional and environmentally responsive multiscale assemblies of living and non-living components. Here, by using inducible genetic circuits and cellular communication circuits to regulate Escherichia coli curli amyloid production, we show that E. coli cells can organize self-assembling amyloid fibrils across multiple length scales, producing amyloid-based materials that are either externally controllable or undergo autonomous patterning. We also interfaced curli fibrils with inorganic materials, such as gold nanoparticles (AuNPs) and quantum dots (QDs), and used these capabilities to create an environmentally responsive biofilm-based electrical switch, produce gold nanowires and nanorods, co-localize AuNPs with CdTe/CdS QDs to modulate QD fluorescence lifetimes, and nucleate the formation of fluorescent ZnS QDs. This work lays a foundation for synthesizing, patterning, and controlling functional composite materials with engineered cells

Sequence-specific antimicrobials using efficiently delivered RNA-guided nucleases

Current antibiotics tend to be broad spectrum, leading to indiscriminate killing of commensal bacteria and accelerated evolution of drug resistance. Here, we use CRISPR-Cas technology to create antimicrobials whose spectrum of activity is chosen by design. RNA-guided nucleases (RGNs) targeting specific DNA sequences are delivered efficiently to microbial populations using bacteriophage or bacteria carrying plasmids transmissible by conjugation. The DNA targets of RGNs can be undesirable genes or polymorphisms, including antibiotic resistance and virulence determinants in carbapenem-resistant Enterobacteriaceae and enterohemorrhagic Escherichia coli. Delivery of RGNs significantly improves survival in a Galleria mellonella infection model. We also show that RGNs enable modulation of complex bacterial populations by selective knockdown of targeted strains based on genetic signatures. RGNs constitute a class of highly discriminatory, customizable antimicrobials that enact selective pressure at the DNA level to reduce the prevalence of undesired genes, minimize off-target effects and enable programmable remodeling of microbiota.National Institutes of Health (U.S.) (New Innovator Award 1DP2OD008435)National Centers for Systems Biology (U.S.) (Grant 1P50GM098792)United States. Defense Threat Reduction Agency (HDTRA1-14-1-0007)Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies (W911NF13D0001)National Institute of General Medical Sciences (U.S.) (Interdepartmental Biotechnology Training Program 5T32 GM008334)Fonds de la recherche en sante du Quebec (Master's Training Award

A transatlantic perspective on 20 emerging issues in biological engineering

Advances in biological engineering are likely to have substantial impacts on global society. To explore these potential impacts we ran a horizon scanning exercise to capture a range of perspectives on the opportunities and risks presented by biological engineering. We first identified 70 potential issues, and then used an iterative process to prioritise 20 issues that we considered to be emerging, to have potential global impact, and to be relatively unknown outside the field of biological engineering. The issues identified may be of interest to researchers, businesses and policy makers in sectors such as health, energy, agriculture and the environment

CRISPR-based strategies in infectious disease diagnosis and therapy

CRISPR gene-editing technology has the potential to transform the diagnosis and treatment of infectious diseases, but most clinicians are unaware of its broad applicability. Derived from an ancient microbial defence system, these so-called "molecular scissors" enable precise gene editing with a low error rate. However, CRISPR systems can also be targeted against pathogenic DNA or RNA sequences. This potential is being combined with innovative delivery systems to develop new therapeutic approaches to infectious diseases.info:eu-repo/semantics/publishedVersio

Phage engineering: how advances in molecular biology and synthetic biology are being utilized to enhance the therapeutic potential of bacteriophages

Background The therapeutic potential of bacteriophages has been debated since their first isolation and characterisation in the early 20th century. However, a lack of consistency in application and observed efficacy during their early use meant that upon the discovery of antibiotic compounds research in the field of phage therapy quickly slowed. The rise of antibiotic resistance in bacteria and improvements in our abilities to modify and manipulate DNA, especially in the context of small viral genomes, has led to a recent resurgence of interest in utilising phage as antimicrobial therapeutics. Results In this article a number of results from the literature that have aimed to address key issues regarding the utility and efficacy of phage as antimicrobial therapeutics utilising molecular biology and synthetic biology approaches will be introduced and discussed, giving a general view of the recent progress in the field. Conclusions Advances in molecular biology and synthetic biology have enabled rapid progress in the field of phage engineering, with this article highlighting a number of promising strategies developed to optimise phages for the treatment of bacterial disease. Whilst many of the same issues that have historically limited the use of phages as therapeutics still exist, these modifications, or combinations thereof, may form a basis upon which future advances can be built. A focus on rigorous in vivo testing and investment in clinical trials for promising candidate phages may be required for the field to truly mature, but there is renewed hope that the potential benefits of phage therapy may finally be realised