Non-genetic photostimulation, which allows for control over cellular activity via the use of cell-targeting phototransducers, is widely used nowadays to study and modulate/restore biological ...functions. This approach relies on non-covalent interactions between the phototransducer and the cell membrane, thus implying that cell conditions and membrane status can dictate the effectiveness of the method. For instance, although immortalized cell lines are traditionally used in photostimulation experiments, it has been demonstrated that the number of passages they undergo is correlated to the worsening of cell conditions. In principle, this could impact cell responsivity against exogenous stressors, including photostimulation. However, these aspects have usually been neglected in previous experiments. In this work, we investigated whether cell passages could affect membrane properties (such as polarity and fluidity). We applied optical spectroscopy and electrophysiological measurements in two different biological models: (i) an epithelial immortalized cell line (HEK-293T cells) and (ii) liposomes. Different numbers of cell passages were compared to a different morphology in the liposome membrane. We demonstrated that cell membranes show a significant decrease in ordered domains upon increasing the passage number. Furthermore, we observed that cell responsivity against external stressors is markedly different between aged and non-aged cells. Firstly, we noted that the thermal-disordering effect that is usually observed in membranes is more evident in aged cells than in non-aged ones. We then set up a photostimulation experiment by using a membrane-targeted azobenzene as a phototransducer (Ziapin2). As an example of a functional consequence of such a condition, we showed that the rate of isomerization of an intramembrane molecular transducer is significantly impaired in aged cells. The reduction in the photoisomerization rate translates in cells with a sustained reduction of the Ziapin2-related hyperpolarization of the membrane potential and an overall increase in the molecule fluorescence. Overall, our results suggest that membrane stimulation strongly depends on membrane order, highlighting the importance of cell passage during the characterization of the stimulation tools. This study can shine light on the correlation between aging and the development of diseases driven by membrane degradation as well as on the different cell responsivities against external stressors, such as temperature and photostimulation.
Una cittadina sul mare, un tirante infrastrutturale da ripensare e riqualificare, una trasversalità disciplinare tra l’architettura e l’urbanistica, il tutto collocato nello scenario amministrativo: ...è questo il contesto in cui si cala oggi la città di Senigallia. Attraverso una sperimentazione puntuale s’indaga sulle possibilità, da parte dell’amministrazione locale, di riqualificare la città che esiste, attraverso l’uso del dispositivo urbanistico e del progetto di architettura.
A seaside town, a tie infrastructure that needs to be redesigned and redeveloped, an interaction between architecture and urbanism; all these things are seen in the perspective of a necessary intervention that should be carried out by public administration: this is the context in which today the city of Senigallia should be placed today. What follows is a comprehensive research on the possibility of redeveloping the city through the use of town planning rules and an architectural project.
Photodynamic inhibition (PDI) of bacteria represents a powerful strategy for dealing with multidrug-resistant pathogens and infections, as it exhibits minimal development of antibiotic resistance. ...The PDI action stems from the generation of a triplet state in the photosensitizer (PS), which subsequently transfers energy or electrons to molecular oxygen, resulting in the formation of reactive oxygen species (ROS). These ROS are then able to damage cells, eventually causing bacterial eradication. Enhancing the efficacy of PDI includes the introduction of heavy atoms to augment triplet generation in the PS, as well as membrane intercalation to circumvent the problem of the short lifetime of ROS. However, the former approach can pose safety and environmental concerns, while achieving stable membrane partitioning remains challenging due to the complex outer envelope of bacteria. Here, we introduce a novel PS, consisting of a metal-free donor-acceptor thiophene-based conjugate molecule (
BV-1
). It presents several advantageous features for achieving effective PDI, namely: (i) it exhibits strong light absorption due to the conjugated donor-acceptor moieties; (ii) it exhibits spontaneous and stable membrane partitioning thanks to its amphiphilicity, accompanied by a strong fluorescence turn-on; (iii) it undergoes metal-free intersystem crossing, which occurs preferentially when the molecule resides in the membrane. All these properties, which we rationalized
via
optical spectroscopies and calculations, enable the effective eradication of
Escherichia coli
, with an inhibition concentration that is below that of current state-of-the-art treatments. Our approach holds significant potential for the development of new PS for controlling bacterial infections, particularly those caused by Gram-negative bacteria.
The molecule
BV-1
is designed to target the bacterial membrane and produce reactive oxygen species at this location, leading to
E. coli
photo-inhibition at a relatively low minimum inhibition concentration.
The viscosity of cell membranes is a crucial parameter that affects the diffusion of small molecules both across and within the lipid membrane and that is related to several diseases. Therefore, the ...possibility to measure quantitatively membrane viscosity on the nanoscale is of great interest. Here, we report a complete investigation of the photophysics of an amphiphilic membrane-targeted azobenzene (ZIAPIN2) and we propose its use as a viscosity probe for cell membranes. We exploit ZIAPIN2
-
photoisomerization to develop a molecular viscometer and to assess the viscosity of
bacteria membranes employing time-resolved fluorescence spectroscopy. Fluorescence lifetime measurements of ZIAPIN2 in
bacteria suspensions correctly indicate that the membrane viscosity decreases as the temperature of the sample increases. Given the non-homogeneity and the anisotropy of cell membranes, as supported by the photophysical characterization of the probe within the lipid bilayer, we shed new light on the intricate membrane rheology.
Bio‐Polymorphs
In article number 2302756, Guglielmo Lanzani, Francesca Di Maria, and co‐workers report the intracellular formation of crystalline, fluorescent, and conductive fibers. These cell‐made ...“bio” polymorphic materials have the unique ability to “connect” cells by penetrating the plasma membrane of neighboring cells without killing them and to conform/adapt to the cellular movement, indicating high fiber flexibility and potentially allowing for dynamic interactions and information exchange.
The assembly of supramolecular structures within living systems is an innovative approach for introducing artificial constructs and developing biomaterials capable of influencing and/or regulating ...the biological responses of living organisms. By integrating chemical, photophysical, morphological, and structural characterizations, it is shown that the cell‐driven assembly of 2,6‐diphenyl‐3,5‐dimethyl‐dithieno3,2‐b:2′,3′‐dthiophene‐4,4‐dioxide (DTTO) molecules into fibers results in the formation of a “biologically assisted” polymorphic form, hence the term bio‐polymorph. Indeed, X‐ray diffraction reveals that cell‐grown DTTO fibers present a unique molecular packing leading to specific morphological, optical, and electrical properties. Monitoring the process of fiber formation in cells with time‐resolved photoluminescence, it is established that cellular machinery is necessary for fiber production and a non‐classical nucleation mechanism for their growth is postulated. These biomaterials may have disruptive applications in the stimulation and sense of living cells, but more crucially, the study of their genesis and properties broadens the understanding of life beyond the native components of cells.
Within live cells, DTTO molecules form amorphous spherical clusters which subsequently accumulate, coalesce, and lead to the formation of fibrous crystals interconnecting different cells. Remarkably, cells produce a distinctive crystalline form, that is, a bio‐polymorph, which cannot be replicated outside cells. These fibers offer a new approach for artificially connecting cells and hold the potential for creating/regenerating cellular communication networks.
Light-driven modulation of neuronal activity at high spatial-temporal resolution is becoming of high interest in neuroscience. In addition to optogenetics, nongenetic membrane-targeted nanomachines ...that alter the electrical state of the neuronal membranes are in demand. Here, we engineered and characterized a photoswitchable conjugated compound (BV-1) that spontaneously partitions into the neuronal membrane and undergoes a charge transfer upon light stimulation. The activity of primary neurons is not affected in the dark, whereas millisecond light pulses of cyan light induce a progressive decrease in membrane resistance and an increase in inward current matched to a progressive depolarization and action potential firing. We found that illumination of BV-1 induces oxidation of membrane phospholipids, which is necessary for the electrophysiological effects and is associated with decreased membrane tension and increased membrane fluidity. Time-resolved atomic force microscopy and molecular dynamics simulations performed on planar lipid bilayers revealed that the underlying mechanism is a light-driven formation of pore-like structures across the plasma membrane. Such a phenomenon decreases membrane resistance and increases permeability to monovalent cations, namely, Na+, mimicking the effects of antifungal polyenes. The same effect on membrane resistance was also observed in nonexcitable cells. When sustained light stimulations are applied, neuronal swelling and death occur. The light-controlled pore-forming properties of BV-1 allow performing “on-demand” light-induced membrane poration to rapidly shift from cell-attached to perforated whole-cell patch-clamp configuration. Administration of BV-1 to ex vivo retinal explants or in vivo primary visual cortex elicited neuronal firing in response to short trains of light stimuli, followed by activity silencing upon prolonged light stimulations. BV-1 represents a versatile molecular nanomachine whose properties can be exploited to induce either photostimulation or space-specific cell death, depending on the pattern and duration of light stimulation.
The viscosity of cell membranes is a crucial parameter that affects the diffusion of small molecules both across and within the lipidic membrane and that is related to several diseases. Therefore, ...the possibility to measure quantitatively membrane viscosity on the nanoscale is of great interest. Here, we report a complete investigation of the photophysics of an amphiphilic membrane-targeted azobenzene (ZIAPIN2) and we validate its use as viscosity probe for cell membranes. We exploit ZIAPIN2 the trans-cis photoisomerization to develop a molecular viscometer and to assess the viscosity of Escherichia coli bacteria membranes employing time-resolved fluorescence spectroscopy. Lifetime measurements of ZIAPIN2 in E. coli bacteria suspensions correctly indicate that membrane viscosity decreases as the samples were heated up. Our results report a membrane viscosity value in live E. coli cells going from 10 to 5 cP, increasing the temperature from 22 {\deg}C up to 40 {\deg}C.
A 5‐year‐old spayed female American Staffordshire was referred for weakness, reluctance to move and distension of the abdomen. Three weeks before, the dog underwent surgery for excision of a nodular ...mass suspected to be a non‐epitheliotropic cutaneous T‐cell lymphoma (NE‐CTCL). Computed tomography revealed heterogeneous enhancing mesenteric masses and nodular lesions of soft tissue density, and infiltration of the abdominal muscular wall. Moreover, a pattern of diffuse muscle nodules in the skeletal muscles was visible, with lesions showing homogenous, heterogeneous or ring enhancement. Necrosis was histologically observed and these lesions were infiltrated by CD3‐positive and CD20‐, CD79a‐ and Iba1‐negative neoplastic lymphocytes. On the basis of the immunopathological features metastatic NE‐CTCL was suspected. Skeletal muscle metastasis has been rarely reported in small animals and this case report further confirms that this possibility should be considered in dogs with lymphoma.
Skeletal muscles metastases are considered quite rare in small animals.
When it occurs, muscle metastases typically involve paravertebral muscle and hind limb.
Whole‐body CT is of paramount importance in patients affected by neoplasms with potential systemic metastases.
Management of a crime is the process of ensuring accurate and effective collection and preservation of physical evidence. Forensic botany can provide significant supporting evidences during criminal ...investigations. The aim of this study is to demonstrate the importance of forensic botany in the crime scene. We reported a case of a woman affected by dementia who had disappeared from nursing care and was found dead near the banks of a river that flowed under a railroad. Two possible ways of access to crime scene were identified and denominated “Path A” and “Path B.” Both types of soil and plants were identified. Botanical survey was performed. Some samples of Xanthium Orientalis subsp. Italicum were identified. The fall of woman resulted in external injuries and vertebral fracture at autopsy. The botanical evidence is important when crime scene and autopsy findings are not sufficient to define the dynamics and the modality of death.
