Identification of Early Stage Liver Fibrosis by Modifications in the Interstitial Space Diffusive Microenvironment Using Fluorescent Single-Walled Carbon Nanotubes.

During liver fibrosis, recurrent hepatic injuries lead to the accumulation of collagen and other extracellular matrix components in the interstitial space, ultimately disrupting liver functions. Early stages of liver fibrosis may be reversible, but opportunities for diagnosis at these stages are currently limited. Here, we show that the alterations of the interstitial space associated with fibrosis can be probed by tracking individual fluorescent single-walled carbon nanotubes (SWCNTs) diffusing in that space. In a mouse model of early liver fibrosis, we find that nanotubes generally explore elongated areas, whose lengths decrease as the disease progresses, even in regions where histopathological examination does not reveal fibrosis yet. Furthermore, this decrease in nanotube mobility is a purely geometrical effect as the instantaneous nanotube diffusivity stays unmodified. This work establishes the promise of SWCNTs both for diagnosing liver fibrosis at an early stage and for more in-depth studies of the biophysical effects of the disease.

Trustworthy clinical AI solutions: A unified review of uncertainty quantification in Deep Learning models for medical image analysis.

The full acceptance of Deep Learning (DL) models in the clinical field is rather low with respect to the quantity of high-performing solutions reported in the literature. End users are particularly reluctant to rely on the opaque predictions of DL models. Uncertainty quantification methods have been proposed in the literature as a potential solution, to reduce the black-box effect of DL models and increase the interpretability and the acceptability of the result by the final user. In this review, we propose an overview of the existing methods to quantify uncertainty associated with DL predictions. We focus on applications to medical image analysis, which present specific challenges due to the high dimensionality of images and their variable quality, as well as constraints associated with real-world clinical routine. Moreover, we discuss the concept of structural uncertainty, a corpus of methods to facilitate the alignment of segmentation uncertainty estimates with clinical attention. We then discuss the evaluation protocols to validate the relevance of uncertainty estimates. Finally, we highlight the open challenges for uncertainty quantification in the medical field.

A comparison between the vaginal patch plastron associated with the anterior sacrospinous fixation and the Uphold™ LITE vaginal support system for the treatment of advanced anterior vaginal wall prolapse.

OBJECTIVE: The aim of the present study was to compare efficacy and safety of the vaginal patch plastron (VPP) associated to the anterior sacrospinous fixation (SSLF-A) with a TVM procedure (Uphold™ LITE support-system) for the treatment of the advanced anterior vaginal wall prolapse. STUDY DESIGN: Single-center retrospective study. Women with symptomatic anterior prolapse ≥ III stage according to the POP-quantification (POP-Q) system and submitted to the VPP associated with the SSLF-A or to the Uphold™ procedure were included. Primary outcome was to compare objective and subjective cystocele relapse and reoperation rate at 6- and 12-month follow-up. Secondary outcome was to describe peri- and postoperative complications. Pearson chi-square test and exact Fisher test were adopted for categorical variables, while intergroup Mann-Whitney U test and intragroup Wilcoxon Rank Sum Test for continuous variables; the statistical analysis was conducted at 95 % confidence level. RESULTS: Fifty-five women in VPP-group and 118 women in Uphold-group were included. At 6-month follow-up, objective anterior relapse in VPP-group (3/55, 5.4 %) was like Uphold-group (5/118, 4.2 %; p = 0.71), as well as objective apical relapse (0/55, 0 % vs 3/118, 2.5 %; p = 0.55); no significant difference emerged in bulge symptoms (1/55, 1.8 % vs 5/118, 4.2 %; p = 0.67). At 12-month follow-up women were telephonically investigated; no significant difference emerged in bulge symptoms (1/55, 1.8 % vs 6/118, 5.1 %; p = 0.43). Reoperation rate for the composite outcome POP relapse, stress urinary incontinence (SUI) and remotion of the TVM resulted lower in the VPP group (1/55, 1.8 % vs 13/118, 11 %; p = 0.03). Post-operative buttock pain (32/55, 58.2 % vs 24/118, 20.3 %; p < 0.0001) and post-operative urinary retention (16/55, 29.1 % vs 6/118, 5.1 %; p < 0.0001) were higher in VPP-group, with a complete resolution between 2 and 3 weeks after treatment. CONCLUSION: VPP associated with SSLF-A was as effective as Uphold™ LITE support-system for both anterior and central compartment prolapse treatment at 6- and 12-month follow-up. VPP-group presented a lower reoperation rate for the composite outcome prolapse relapse repair, SUI, and removal of the mesh.

Differential near-infrared imaging of heterocysts using single-walled carbon nanotubes.

The internalization of near-infrared (NIR) optical nanoprobes in photosynthetic microbes can be exploited for applications ranging from energy conversion to biomolecule delivery. However, the intrinsic, species-dependent properties of microbial cell walls, including their surface charge density, composition, thickness, and elasticity, can severely impact nanoprobe uptake and affect the cellular response. An examination of the interaction of the optical nanoprobe in various species and its impact on cell viability is, therefore, imperative for the development of new imaging technologies. Herein, we extend the technology recently developed for internalizing fluorescent single-walled carbon nanotubes (SWCNTs) in prokaryotes, specifically unicellular Synechocystis sp. PCC 6803, to a filamentous cyanobacterial strain, Nostoc punctiforme. Using a combination of NIR fluorescence, scanning electron microscopy (SEM), and Raman spectroscopy, we investigate uptake in vegetative cells as well as differentiated heterocysts. We demonstrate a strong dependence of long-term cell integrity, activity, and viability on SWCNT surface functionalization. We further show differential uptake of SWCNTs across a single filament, with positively charged functionalized SWCNTs preferentially localizing within the heterocysts of the filament. This cell dependency of the nanoparticle internalization motivates the use of SWCNTs as a NIR stain for monitoring cell differentiation.

The Vaginal Patch Plastron Associated to the Anterior Sacrospinous Ligament Fixation for the Treatment of Advanced Anterior Vaginal Wall Prolapse.

Background: this study aims to compare the efficacy and safety of vaginal patch plastron (VPP) associated to anterior sacrospinous ligament fixation (SSLF-A) with SSLF-A associated or not to the anterior colporrhaphy (AC) for cystocele treatment. Methods: single-center retrospective study in women with cystocele ≥ III stage submitted to surgery. The primary outcome was to compare objective and subjective cystocele relapse and reoperation rate at follow-up > 6 months. The secondary outcome was to describe peri- and postoperative complications and risk factors for cystocele objective relapse. Results: 75 women were submitted to SSLF-A and 61 women to VPP. VPP objective and subjective relapse (6.5%, 4/61 and 1.1%, 1/61) were lower than SSLF-A (26.7%, 20/75 and 20%, 15/75; p = 0.002 and p = 0.001, respectively). SSLF-A had a higher reintervention rate, but not significantly (6.6%, 5/75 vs. 0%, 0/61; p = 0.06). Previous hysterectomy was a risk factor (HR 4; 1.3−12.1) while VPP was protective factor (HR 0.2; 0.1−0.9) for cystocele anatomical relapse. Postoperative buttock pain was more prevalent in VPP (57.4%, 35/75 vs. 34.7%, 26/61; p = 0.01). Conclusions: VPP is effective and safe for advanced cystocele treatment, with lower objective and subjective relapse rates in comparison to isolated SSLF-A or associated with the AC.

Carbon nanotube uptake in cyanobacteria for near-infrared imaging and enhanced bioelectricity generation in living photovoltaics.

The distinctive properties of single-walled carbon nanotubes (SWCNTs) have inspired the development of many novel applications in the field of cell nanobiotechnology. However, studies thus far have not explored the effect of SWCNT functionalization on transport across the cell walls of prokaryotes. We explore the uptake of SWCNTs in Gram-negative cyanobacteria and demonstrate a passive length-dependent and selective internalization of SWCNTs decorated with positively charged biomolecules. We show that lysozyme-coated SWCNTs spontaneously penetrate the cell walls of a unicellular strain and a multicellular strain. A custom-built spinning-disc confocal microscope was used to image the distinct near-infrared SWCNT fluorescence within the autofluorescent cells, revealing a highly inhomogeneous distribution of SWCNTs. Real-time near-infrared monitoring of cell growth and division reveal that the SWCNTs are inherited by daughter cells. Moreover, these nanobionic living cells retained photosynthetic activity and showed an improved photo-exoelectrogenicity when incorporated into bioelectrochemical devices.

Synthetic Biology: A Solution for Tackling Nanomaterial Challenges.

Bioengineers have mastered practical techniques for tuning a biomaterial's properties with only limited information on the relationship between the material's structure and function. These techniques have been quintessential to engineering proteins, which are most often riddled with ill-defined structure-function relationships. In this Perspective, we review bioengineering approaches aimed at overcoming the elusive protein structure-function relation. We extend these principles to engineering synthetic nanomaterials, specifically applying the underlying theory to optical sensors based on single-stranded DNA-wrapped single-walled carbon nanotubes (ssDNA-SWCNTs). Bioengineering techniques such as directed evolution, computational design, and noncanonical synthesis are reviewed in the broader context of nanomaterials engineering. We further provide an order-of-magnitude analysis of empirical approaches that rely on random or guided searches for designing new nanomaterials. The underlying concepts presented in these approaches can be further extended to a broad range of engineering fields confronted with empirical design strategies, including catalysis, metal-organic frameworks (MOFs), pharmaceutical dosing, and optimization algorithms.

Templating colloidal sieves for tuning nanotube surface interactions and optical sensor responses.

Surfactants offer a tunable approach for modulating the exposed surface area of a nanoparticle. They further present a scalable and cost-effective means for suspending single-walled carbon nanotubes (SWCNTs), which have demonstrated practical use as fluorescence sensors. Though surfactant suspensions show record quantum yields for SWCNTs in aqueous solutions, they lack the selectivity that is vital for optical sensing. We present a new method for controlling the selectivity of optical SWCNT sensors through colloidal templating of the exposed surface area. Colloidal nanotube sensors were obtained using various concentrations of sodium cholate, and their performances were compared to DNA-SWCNT optical sensors. Sensor responses were measured against a library of bioanalytes, including neurotransmitters, amino acids, and sugars. We report an intensity response towards dopamine and serotonin for all sodium cholate-suspended SWCNT concentrations. We further identify a selective, 14.1 nm and 10.3 nm wavelength red-shifting response to serotonin for SWCNTs suspended in 1.5 and 0.5 mM sodium cholate, respectively. Through controlled, adsorption-based tuning of the nanotube surface, this study demonstrates the applicability of sub-critical colloidal suspensions to achieve selectivities exceeding those previously reported for DNA-SWCNT sensors.

Directed evolution of the optoelectronic properties of synthetic nanomaterials.

Directed evolution is a powerful approach to tailor protein properties toward new or enhanced functions. Herein, we use directed evolution to engineer the optoelectronic properties of DNA-wrapped single-walled carbon nanotube sensors through DNA mutation. This approach leads to an improvement in the fluorescence intensity of 56% following two evolution cycles.

Spinning-disc confocal microscopy in the second near-infrared window (NIR-II).

Fluorescence microscopy in the second near-infrared optical window (NIR-II, 1000-1350 nm) has become a technique of choice for non-invasive in vivo imaging. The deep penetration of NIR light in living tissue, as well as negligible tissue autofluorescence within this optical range, offers increased resolution and contrast with even greater penetration depths. Here, we present a custom-built spinning-disc confocal laser microscope (SDCLM) that is specific to imaging in the NIR-II. The SDCLM achieves a lateral resolution of 0.5 ± 0.1 µm and an axial resolution of 0.6 ± 0.1 µm, showing a ~17% and ~45% enhancement in lateral and axial resolution, respectively, compared to the corresponding wide-field configuration. We furthermore showcase several applications that demonstrate the use of the SDCLM for in situ, spatiotemporal tracking of NIR particles and bioanalytes within both synthetic and biological systems.

Mediatorless, Reversible Optical Nanosensor Enabled through Enzymatic Pocket Doping.

Single-walled carbon nanotubes (SWCNTs) exhibit intrinsic near-infrared fluorescence that benefits from indefinite photostability and tissue transparency, offering a promising basis for in vivo biosensing. Existing SWCNT optical sensors that rely on charge transfer for signal transduction often require exogenous mediators that compromise the stability and biocompatibility of the sensors. This study presents a reversible, mediatorless, near-infrared glucose sensor based on glucose oxidase-wrapped SWCNTs (GOx-SWCNTs). GOx-SWCNTs undergo a selective fluorescence increase in the presence of aldohexoses, with the strongest response toward glucose. When incorporated into a custom-built membrane device, the sensor demonstrates a monotonic increase in initial response rates with increasing glucose concentrations between 3 × 10-3 and 30 × 10-3 m and an apparent Michaelis-Menten constant of KM (app) ≈ 13.9 × 10-3 m. A combination of fluorescence, absorption, and Raman spectroscopy measurements suggests a fluorescence enhancement mechanism based on localized enzymatic doping of SWCNT defect sites that does not rely on added mediators. Removal of glucose reverses the doping effects, resulting in full recovery of the fluorescence intensity. The cyclic addition and removal of glucose is shown to successively enhance and recover fluorescence, demonstrating reversibility that serves as a prerequisite for continuous glucose monitoring.