Investigations of Bio-responsive Peptide-inorganic Nanomaterials

Growth in nanotechnology has been fuelled by miniaturization of electronic systems, development of biomedical sciences and interest in nanomaterials that exhibit interesting properties. Current techniques to fabricate small devices have difficulty in accessing the size range between 10-100 nm, and conjugation of biomolecules with inorganic nanoparticles (NPs) can potentially be used to bridge this gap. Biological functions of living cells operate in the nanoscale and there is great potential in using bionanotechnology to discover new biomedical applications in diagnostics, drug delivery and cancer therapy. In this thesis, N-fluorenylmethoxycarbonyl (Fmoc)-protected peptides are explored as tethers to self-assemble gold NPs. Assembly is characterized by transmission electron microscopy, UV-visible spectroscopy, Raman spectroscopy, zeta potential measurements, dynamic light scattering and a new technique, Nanoparticle Tracking Analysis system (NTA). Solutions of gold NPs exhibit unique colour changes depending on their aggregation state, and the use of peptide-functionalised NPs (peptide-NPs) in a novel approach of protease sensing is developed here. Detection of the protease, Thermolysin from Bacillus thermoproteolyticus Rokko was demonstrated, and design of peptide-NPs was further optimized for detection of two medically relevant proteases, non-bindingto- alpha-chymotrypsin prostate specific antigen (nACT-PSA) and human neutrophil elastase (HNE). nACT-PSA and HNE are proteases related to prostate cancer and lung diseases respectively, and detection of PSA using the engineered peptide-NPs resulted in higher sensitivity than previously reported approaches. Surface enhanced Raman scattering was also used to monitor thermolysin action on peptide-NPs, in a novel approach which gave higher sensitivity than when using UVvisible spectroscopy for detection. The quartz crystal microbalance was also applied in complementary measurements to elucidate enzyme action on the peptides. The successful approach demonstrated here of using peptides to self-assemble gold NPs could pave new ways for the fabrication of small devices. Novel approaches of protease-sensing using peptide-NPs further illustrate potential of nanomaterials for new biomedical applications

Global Trends and Gaps in Research Related to Latent Tuberculosis Infection

Background There is a global commitment to eliminating tuberculosis (TB). It is critical to detect and treat cases of latent TB infection (LTBI), the reservoir of new TB cases. Our study assesses trends in publication of LTBI-related research. Methods We used the keywords (“latent tuberculosis” OR “LTBI” OR “latent TB”) to search the Web of Science for LTBI-related articles published 1995–2018, then classified the results into three research areas: laboratory sciences, clinical research, and public health. We calculated the proportions of LTBI-related articles in each area to three areas combined, the average rates of LTBI-related to all scientific and TB-related articles, and the average annual percent changes (AAPC) in rates for all countries and for the top 13 countries individually and combined publishing LTBI research. Results The proportion of LTBI-related articles increased over time in all research areas, with the highest AAPC in laboratory (38.2%/yr), followed by public health (22.9%/yr) and clinical (15.1%/yr). South Africa (rate ratio [RR] = 8.28, 95% CI 5.68 to 12.08) and India (RR = 2.53, 95% CI 1.74 to 3.69) had higher RRs of overall TB-related articles to all articles, but did not outperform the average of the top 13 countries in the RRs of LTBI-related articles to TB-related articles. Italy (RR = 1.95, 95% CI 1.45 to 2.63), Canada (RR = 1.73, 95% CI 1.28 to 2.34), and Spain (RR = 1.53, 95% CI 1.13 to 2.07) had higher RRs of LTBI-related articles to TB-related articles. Conclusions High TB burden countries (TB incidence \u3e 100 per 100,000 population) published more overall TB-related research, whereas low TB burden countries showed greater focus on LTBI. Given the potential benefits, high TB burden countries should consider increasing their emphasis on LTBI-related research

Characterization of the histone methyltransferase PRDM9 using biochemical, biophysical and chemical biology techniques

PRDM proteins have emerged as important regulators of disease and developmental processes. To gain insight into the mechanistic actions of the PRDM family, we have performed comprehensive characterization of a prototype member protein, the histone methyltransferase PRDM9, using biochemical, biophysical and chemical biology techniques. In the present paper we report the first known molecular characterization of a PRDM9-methylated recombinant histone octamer and the identification of new histone substrates for the enzyme. A single C321P mutant of the PR/SET domain was demonstrated to significantly weaken PRDM9 activity. Additionally, we have optimized a robust biochemical assay amenable to high-throughput screening to facilitate the generation of small-molecule chemical probes for this protein family. The present study has provided valuable insight into the enzymology of an intrinsically active PRDM protein

Investigations of bio-responsive peptide-inorganic nanomaterials

Growth in nanotechnology has been fuelled by miniaturization of electronic systems, development of biomedical sciences and interest in nanomaterials that exhibit interesting properties. Current techniques to fabricate small devices have difficulty in accessing the size range between 10-100 nm, and conjugation of biomolecules with inorganic nanoparticles (NPs) can potentially be used to bridge this gap. Biological functions of living cells operate in the nanoscale and there is great potential in using bionanotechnology to discover new biomedical applications in diagnostics, drug delivery and cancer therapy. In this thesis, N-fluorenylmethoxycarbonyl (Fmoc)-protected peptides are explored as tethers to self-assemble gold NPs. Assembly is characterized by transmission electron microscopy, UV-visible spectroscopy, Raman spectroscopy, zeta potential measurements, dynamic light scattering and a new technique, Nanoparticle Tracking Analysis system (NTA). Solutions of gold NPs exhibit unique colour changes depending on their aggregation state, and the use of peptide-functionalised NPs (peptide-NPs) in a novel approach of protease sensing is developed here. Detection of the protease, Thermolysin from Bacillus thermoproteolyticus Rokko was demonstrated, and design of peptide-NPs was further optimized for detection of two medically relevant proteases, non-bindingto- alpha-chymotrypsin prostate specific antigen (nACT-PSA) and human neutrophil elastase (HNE). nACT-PSA and HNE are proteases related to prostate cancer and lung diseases respectively, and detection of PSA using the engineered peptide-NPs resulted in higher sensitivity than previously reported approaches. Surface enhanced Raman scattering was also used to monitor thermolysin action on peptide-NPs, in a novel approach which gave higher sensitivity than when using UVvisible spectroscopy for detection. The quartz crystal microbalance was also applied in complementary measurements to elucidate enzyme action on the peptides. The successful approach demonstrated here of using peptides to self-assemble gold NPs could pave new ways for the fabrication of small devices. Novel approaches of protease-sensing using peptide-NPs further illustrate potential of nanomaterials for new biomedical applications.EThOS - Electronic Theses Online ServiceUniversities UK - ORS scholarship.GBUnited Kingdo

Protease-triggered dispersion of nanoparticle assemblies

We present a new highly sensitive method for detection of proteases based on triggered dispersion of gold nanoparticle assemblies

What do we know about SARS-CoV-2 transmission? A systematic review and meta-analysis of the secondary attack rate and associated risk factors.

IntroductionCurrent SARS-CoV-2 containment measures rely on controlling viral transmission. Effective prioritization can be determined by understanding SARS-CoV-2 transmission dynamics. We conducted a systematic review and meta-analyses of the secondary attack rate (SAR) in household and healthcare settings. We also examined whether household transmission differed by symptom status of index case, adult and children, and relationship to index case.MethodsWe searched PubMed, medRxiv, and bioRxiv databases between January 1 and July 25, 2020. High-quality studies presenting original data for calculating point estimates and 95% confidence intervals (CI) were included. Random effects models were constructed to pool SAR in household and healthcare settings. Publication bias was assessed by funnel plots and Egger's meta-regression test.Results43 studies met the inclusion criteria for household SAR, 18 for healthcare SAR, and 17 for other settings. The pooled household SAR was 18.1% (95% CI: 15.7%, 20.6%), with significant heterogeneity across studies ranging from 3.9% to 54.9%. SAR of symptomatic index cases was higher than asymptomatic cases (RR: 3.23; 95% CI: 1.46, 7.14). Adults showed higher susceptibility to infection than children (RR: 1.71; 95% CI: 1.35, 2.17). Spouses of index cases were more likely to be infected compared to other household contacts (RR: 2.39; 95% CI: 1.79, 3.19). In healthcare settings, SAR was estimated at 0.7% (95% CI: 0.4%, 1.0%).DiscussionWhile aggressive contact tracing strategies may be appropriate early in an outbreak, as it progresses, measures should transition to account for setting-specific transmission risk. Quarantine may need to cover entire communities while tracing shifts to identifying transmission hotspots and vulnerable populations. Where possible, confirmed cases should be isolated away from the household