Graphene oxide modulates dendritic cell ability to promote T cell activation and cytokine production

An important aspect of immunotherapy is the ability of dendritic cells (DCs) to prime T cell immunity, an approach that has yielded promising results in some early phase clinical trials. However, novel approaches are required to improve DC therapeutic efficacy by enhancing their uptake of, and activation by, disease relevant antigens. The carbon nano-material graphene oxide (GO) may provide a unique way to deliver antigen to innate immune cells and modify their ability to initiate effective adaptive immune responses. We have assessed whether GO of various lateral sizes affects DC activation and function in vitro and in vivo, including their ability to take up, process and present the well-defined model antigen ovalbumin (OVA). We have found that GO flakes are internalised by DCs, while having minimal effect on their viability, activation phenotype or cytokine production. Although adsorption of OVA protein to either small or large GO flakes promoted its uptake into DCs, large GO interfered with OVA processing. In terms of modulation of DC function, delivery of OVA via small GO flakes significantly enhanced DC ability to induce proliferation of OVA-specific CD4⁺ T cells, promoting granzyme B secretion in vitro. On the other hand, delivery of OVA via large GO flakes augmented DC ability to induce proliferation of OVA-specific CD8⁺ T cells, and their production of IFN-γ and granzyme B. Together, these data demonstrate the capacity of GO of different lateral dimensions to act as a promising delivery platform for DC modulation of distinct facets of the adaptive immune response, information that could be exploited for future development of targeted immunotherapies.

High throughput diagnostics and dynamic risk assessment of SARS-CoV-2 variants of concern

BACKGROUND

The rise of new SARS-CoV-2 variants worldwide requires global molecular surveillance strategies to support public health control. Early detection and evaluation of their associated risk of spreading within the population are pivotal.

METHODS

Between April 2020 and February 2021, the UK Lighthouse Labs Network at Alderley Park tested more than eight million nose and throat swab samples for the presence of SARS-CoV-2, via PCR. The assay targeted three genomic regions of the virus: N, Orf1ab and S. Whole-genome next-generation sequencing was used to confirm positive PCR results. Positive results were mapped using the postal district origin of samples to allow real-time tracking of the spread of a new variant through the UK.

FINDINGS

In mid-November 2020, the assay identified an increasing number of S gene negative, N and Orf1ab positive samples. Whole-genome sequencing demonstrated that the loss of S gene detection was due to the appearance of a SARS-CoV-2 lineage (B.1.1.7) designated as Variant of concern (VOC) 202012/01. By the beginning of January 2021, the new SARS-CoV-2 VOC comprised 70% of daily positive samples tested at Alderley Park and ∼98% by the end of February 2021.

INTERPRETATION

The timeline view identified the rapid spread of the new SARS-CoV-2 variant across England during the first three weeks of December. Coupling high-throughput diagnostics and molecular surveillance was pivotal to the early detection of the spread of this variant. The availability of real-time tracking of an emerging variant is an important new tool to inform decision-making authorities for risk mitigation. In a respiratory pandemic, a tool for the timely response to the emergence and spread of a novel variant is vital, even more so when a variant is associated with the enhanced transmission, as has occurred with VOC 202012/01.

FUNDING

None.

Graphene oxide biohybrid layer enhances sensitivity and anticorrosive properties in refractive index sensor

Graphene-based materials are capable of enhancing the refractometric response of prism- and optical fiber-based surface plasmon resonance (SPR) sensors; however, complicated multistep and time-consuming attaching processes could limit their practical applications. Herein, for the first time, we demonstrate the immobilization of graphene oxide (GO) submicrometric sheets onto the surface of a gold-coated single-mode fiber using a coating of fungal self-assembling proteins, the hydrophobins (HFBs), as an adhesive nanolayer. Hetero-core fiber tip SPR structures used in this study, consisting of a mirrored multimode–single-mode fiber structure coated with different thin layers (a chromium layer of 3 nm and a gold layer of 30 nm on top) exhibited a refractive index sensitivity (SRI) of 1842 nm RIU−1 (RIU: refractive index unit) at a refractive index (RI) of 1.36. Self-assembly of GO over the SPR fiber tip via HFB, offered an enhancement of up to 20% in the SRI. Moreover, this HFB-GO coating prevented degradation of the Al thin film mirror caused by corrosive salt-water solutions. The process is very simple, harmless, rapid (around 15 min) and scalable, as it is mostly based on one plasma treatment, which can be performed in large chambers and two dip coating steps, in liquid baths. All these features make the use of self-assembled bio/non-bio hybrid coating a green industrial method to improve the performance of SPR fiber biosensors, if compared with traditional chemical methods. Materials applied in this technology, fungal proteins and derivatives of graphite, are sustainable and largely available.

Green synthesis of luminescent and defect-free bio-nanosheets of MoS2: interfacing two-dimensional crystals with hydrophobins

High quality luminescent nanosheets of MoS₂ interfaced with the amphiphilic protein Vmh2.

Electrostatically driven scalable synthesis of MoS2–graphene hybrid films assisted by hydrophobins

Green synthesis of MoS₂/biofunctionalized graphene hybrid films assisted by Vmh2 hydrophobin for applications in biosensing and photodetection.

Marine fungi as source of new hydrophobins

Hydrophobins have been described as the most powerful surface-active proteins known. They are produced by filamentous fungi and exhibit a distinct amphiphilic structure determining their self-assembly at hydrophilic-hydrophobic interfaces and surfactant properties which have been demonstrated to be useful for several biotechnological applications. The marine environment represents a vast natural resource of new molecules produced by organisms growing in various stressful conditions. This study was focused on the screening of 100 marine fungi from Mycoteca Universitatis Taurinensis (MUT) for the identification of new hydrophobins. Four different methods were set up to extract hydrophobins of class I and II, from the mycelium or the culture broth of fungi. Six fungi were selected as the best producers of hydrophobins endowed with different characteristics. Their ability to form stable amphiphilic films and their emulsification capacity in the presence of olive oil was evaluated.

One-pot synthesis of a gold nanoparticle-Vmh2 hydrophobin nanobiocomplex for glucose monitoring

HydrophobinVmh2 is a small amphiphilic protein, which self-assembles on different surfaces and naturally interacts with glucose. Here, we report on the synthesis of a nanobiocomplex made of polyethylene glycol, Vmh2 and gold nanoparticles by a one-step process and on its ability to recognise glucose in an aqueous solution at 0.3-0.6-1.2 mg ml(-1) concentrations. Even though the Vmh2 proteins are intrinsically bonded to the gold core, effective glucose interaction monitoring was demonstrated by using dynamic light scattering, ultraviolet-visible, polarization-modulated infrared reflection-absorption and x-ray photoelectron spectroscopies. Experimental results highlighted an affinity constant of 7.3 ± 0.3 mg ml(-1) between the nanobiosystem and the sugar, and a detection sensitivity of 0.13 ± 0.06 a.u./mg ml(-1).