Controlled assembly of magnetic nanoparticles on microbubbles for multimodal imaging.

Magnetic microbubbles (MMBs) consisting of microbubbles (MBs) and magnetic nanoparticles (MNPs) were synthesized for use as novel markers for improving multifunctional biomedical imaging. The MMBs were fabricated by assembling MNPs in different concentrations on the surfaces of MBs. The relationships between the structure, magnetic properties, stability of the MMBs, and their use in magnetic resonance/ultrasound (MR/US) dual imaging applications were determined. The MNPs used were NPs of 3-aminopropyltriethoxysilane (APTS)-functionalized superparamagnetic iron oxide γ-Fe2O3 (SPIO). SPIO was assembled on the surfaces of polymer MBs using a "surface-coating" approach. An analysis of the underlying mechanism showed that the synergistic effects of covalent coupling, electrostatic adsorption, and aggregation of the MNPs allowed them to be unevenly assembled in large amounts on the surfaces of the MBs. With an increase in the MNP loading amount, the magnetic properties of the MMBs improved significantly; in this way, the shell structure and mechanical properties of the MMBs could be modified. For surface densities ranging from 2.45 × 10(-7) µg per MMB to 8.45 × 10(-7) µg per MMB, in vitro MR/US imaging experiments showed that, with an increase in the number of MNPs on the surfaces of the MBs, the MMBs exhibited better T2 MR imaging contrast, as well as an increase in the US contrast for longer durations. In vivo experiments also showed that, by optimizing the structure of the MMBs, enhanced MR/US dual-modality image signals could be obtained for mouse tumors. Therefore, by adjusting the shell composition of MBs through the assembly of MNPs in different concentrations, MMBs with good magnetic and acoustic properties for MR/US dual-modality imaging contrast agents could be obtained.

Hierarchical Porous Reduced Graphene Oxide/Poly(l-lactic acid) Fiber Films: The Influence of Recrystallization on Strength.

Electrospinning technology for fabricating nanofiber films and the Hummer method for synthesizing graphene oxide (GO), along with subsequent reduction, have been significantly advanced, demonstrating immense potential for large-scale industrial applications. Nanofibrous films loaded with reduced graphene oxide (rGO) have been widely explored for their applications in electromagnetic shielding, the biomedical fields, and pollutant adsorption. However, fragile mechanical performance of electrospun fibers with limited surface post-treatment methods has somewhat hindered their further industrial development. In response to this challenge, we propose a dual-regulation strategy involving post-treatment to form porous nanofiber films and the controlled flake size of rGO for surface coating during preparation. This approach aims to achieve poly(l-lactic acid) (PLLA)/rGO electrospun fibrous films with enhanced mechanical properties. It offers a roadmap for the continued application and standardized production of fibrous films loaded with rGO.

A Knitted and MXenzyme-Integrated Dressing for Geriatrics Diagnosis and Ulcer Healing.

Integrated diagnostic and therapeutic dressings are desirable to relieve diabetic patients who often suffer from diabetic foot ulcers (DFUs) and peripheral vascular diseases (PVDs). However, it is highly difficult to monitor the pulse waves with fidelity under wet environments and connect the waveforms to diseases through a small strain sensor. Additionally, immobilizing MXenzyme to regulate spatially heterogeneous levels of reactive oxygen species (ROS) and applying active intervention to enhance ulcer healing on a single structure remain a complex task. To address these issues, we designed a multiscale wearable dressing comprising a knitted all-textile sensing array for quantitatively investigating the pulse wave toward PVD diagnosis. MXenzyme was loaded onto the dressing to provide multiple enzyme mimics for anti-inflammatory activities and deliver electrical stimulation to promote wound growth. In mice, we demonstrate that high and uniform expression of the vascular endothelial growth factor (VEGF) is observed only in the group undergoing dual mediation with electrical stimulation and MXenzyme. This observation indicates that the engineered wound dressing has the capability to accelerate healing in DFU. In human patient evaluations, the engineered dressing distinguishes vascular compliance and pulse period, enabling the diagnosis of arteriosclerosis and return blockage, two typical PVDs. The designed and engineered multiscale dressing achieves the purpose of integrating diagnostic peripheral vessel health monitoring and ulcer healing therapeutics for satisfying the practical clinical requirements of geriatric patients.

Contact Lens Sensor with Anti-jamming Capability and High Sensitivity for Intraocular Pressure Monitoring.

Contact lens sensors provide a noninvasive approach for intraocular pressure (IOP) monitoring in patients with glaucoma. Accurate measurement of this imperceptible pressure variation requires highly sensitive sensors in the absence of simultaneously amplifying IOP signal and blinking-induced noise. However, current noise-reduction methods rely on external filter circuits, which thicken contact lenses and reduce signal quality. Here, we introduce a contact lens strain sensor with an anti-jamming ability by utilizing a self-lubricating layer to reduce the coefficient of friction (COF) to remove the interference from the tangential force. The sensor achieves exceptionally high sensitivity due to the strain concentration layout and the confined occurrence of sympatric microcracks. The animal tests prove our lens can accurately detect IOP safely and reliably.

Revisable and high-strength wheel-spun alginate/graphene oxide based fibrous rods towards a flexible and biodegradable rib internal fixation system.

The intramedullary splint insertion fixation system is the mainstream clinical solution to severe rib fractures. However, the titanium alloy scaffolds have limitations in biocompatibility, flexibility and complexity of surgeries. Here we present a revisable wheel-spun alginate (Alg)/graphene oxide (GO)-based fibrous rod as a potential alternative for a rib internal fixation system. The reversible fusion and fission capability was obtained by optimized Alg/GO blended spinning and GO coating post-treatment. The mechanical performance of the demonstrated rod samples matches the properties of the human rib. A self-designed cubic matrix was used to conduct in situ cell culture. In vitro evaluation not only confirms the cell viability and migration on the fibers' surface, but also investigated the degradation and fission performance of fibrous rods. With a simple, minimally invasive implantation and controlled swelling, Alg/GO fibrous rods are able to tightly fix the rib fracture wound while maintaining sufficient flexibility.

Efficient and recyclable sericin-derived carbon aerogel for oils and organic solvents adsorption.

Sericin, an industrial waste of the silk industry, is a promising precursor for adsorbent preparation. In this work, an efficient and novel sericin-derived carbon aerogel (SCA) was used to improve the adsorption efficiency of oils and organic solvents. The SCA demonstrated a high-efficiency sorption capacity of not only soybean oil (adsorption capacity reached up to 167.69 times its weight) but also chloroform and methylene chloride (adsorption capacity of 193.67 g/g and 173.25 g/g respectively). It is observed that SCA could be regenerated multiple times through combustion and after five cycles, its adsorbability to ethanol, dimethyl sulfoxide, and soybean oil remained high at 59.08 g/g, 59.34 g/g, and 137.36 g/g, respectively. The physical and chemical characteristics of sericin and SCA were analyzed using Scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), Raman spectra and Fourier transform infrared spectroscopy (FTIR) analysis. The results suggest that SCA is an adsorbent with excellent properties and can significantly increase the adsorption capacity of oils and organic solvents. The overall results indicate that SCA is effectively used as an adsorbent for the adsorption of oils and organic solvents, which will contribute to reduce the discharge of sericin-containing wastewater and alleviate pollution caused by oil and organic solvent leakage.

Hierarchical Porous Recycled PET Nanofibers for High-Efficiency Aerosols and Virus Capturing.

Plastic crisis, especially for poly(ethylene terephthalate) (PET) bottles, has been one of the greatest challenges for the earth and human beings. Processing recycled PET (rPET) into functional materials has the dual significance of both sustainable development and economy. Providing more possibilities for the engineered application of rPET, porous PET fibers can further enhance the high specific surface area of electrospun membranes. Here, we use a two-step strategy of electrospinning and postprocessing to successfully control the surface morphology of rPET fibers. Through a series of optical and thermal characterizations, the porous morphology formation mechanism and crystallinity induced by solvents of rPET fibers were discussed. Then, this work further investigated both PM2.5 air pollutants and protein filtration performance of rPET fibrous membrane. The high capture capability of rPET membrane demonstrated its potential application as an integrated high-efficiency aerosol filtering solution.

High strength and strain alginate fibers by a novel wheel spinning technique for knitting stretchable and biocompatible wound-care materials.

Alginate fibrous materials have been applied as wound dressing to enhance wound healing due to its nontoxic, biodegradable, and hemostatic nature. Conventional nonwoven fabrication tactics, however, showed weakness in inflammation, degradation stability and mechanical properties. Herein, the wet-spun alginate fibers were prepared by a novel wheel spinning technique, then knitted into wound dressing. Benefiting from optimized wet spinning parameters and the agglomeration of alginate multimers, the fibers were endowed with elevated mechanical performances and biodegradability, which allowed for the feasibility of knitting wound-care materials. Using the new wheel spinning technique, high strength alginate fibers with 173 MPa were produced with breaking strain up to 18% and toughness of 16.16 MJ*m-3. Meanwhile, alginate fibers with high breaking strain reaching 35% were produced with tensile strength of 135 MPa and toughness of 37.47 MJ*m-3. The overall mechanical performances of these alginate fibers with high breaking strain are significantly higher (up to 2 times) than those published in the literature in term of toughness. In vitro degradation evaluation revealed that this wet spun fibrous dressing had good aqueous absorbency (50%) and sustained biodegradation properties. Furthermore, the consequent cell viability study also proved that this alginate knitted fabric is biocompatible for being applied as wound dressing.

Hierarchical porous silk fibroin/poly(L-lactic acid) fibrous membranes towards vascular scaffolds.

Fibrous membranes played an important role to prepare tubular scaffolds for muscular artery regeneration. In this study, a strategy has been developed to combine silk fibroin (SF) with highly porous electrospun poly(L-lactic acid) (PLLA) fibrous membrane towards vascular scaffolds. After PLLA fibres were electrospun and collected, they were immersed into acetone to generate a porous structure with ultra-high surface area. While the pores on PLLA fibres were fulfilled with SF solution and dried, SF was coated uniformly and tightly on PLLA fibres. A multi-layer tubular structure of the tunica media was simulated by winding and stacking a strip of electrospun fibrous membrane. In vitro viability and morphology studies of A7r5 smooth muscle cells were undertaken for up to 14 days. Because the hydrophilicity of SF/PLLA composite fibres were improved dramatically, it had a positive effect on cell adhesion rate (97%) and proliferation (64.4%). Moreover, good cell morphology was observed via a multiphoton laser confocal microscope on SF/PLLA bioactive materials. These results demonstrated that the hierarchical porous SF/PLLA fibrous membranes are promising off-the-shelf scaffolds for muscular artery regeneration.

Design of an Ultrasensitive Flexible Bend Sensor Using a Silver-Doped Oriented Poly(vinylidene fluoride) Nanofiber Web for Respiratory Monitoring.

We propose a design strategy to fabricate a flexible bend sensor (BS) with ultrasensitivity toward airflow using all-poly(vinylidene fluoride) (PVDF) nanofiber web-based sensing elements and electrodes to monitor human respiration. The unique electrospinning (rotational speed of collector of 2000 rpm and tip-to-collector distance of 4 cm) with silver nanoparticle interfacing was introduced to prepare a Ag-doped oriented PVDF nanofiber web with high ß-phase content as a sensing element (AgOriPVDF, ß-phase crystallinity ∼44.5%). After that, a portion of the prepared AgOriPVDF was processed into a flexible and electrically conductive electrode through an electroless silver plating technique (SP-AgOriPVDF). Interestingly, the encapsulated AgOriPVDF BS with the SP-AgOriPVDF electrode exhibited superior piezoelectric bending response (open-circuit peak-to-peak output voltage, Vp-p ≈ 4.6 V) to injected airflow, which is more than 200 times higher than that of the unpackaged randomly aligned PVDF nanofiber web BS with a conductive tape electrode (Vp-p ≈ 0.02 V). In addition, the factors influencing the bend sensitivity of the BS such as the ß-phase content, nanofiber orientation, flexibility of the electrode, and so forth were thoroughly analyzed and then discussed. We also demonstrated that the AgOriPVDF BS has sufficient capability to detect and identify various respiratory signals, presenting a great potential for wearable applications, for example, smart respiratory protective equipment.

Moisture-Resilient Graphene-Dyed Wool Fabric for Strain Sensing.

E-textile consisting of natural fabrics has become a promising material to construct wearable sensors due to its comfortability and breathability on the human body. However, the reported fabric-based e-textile materials, such as graphene-treated cotton, silk, and flax, generally suffer from the electrical and mechanical instability in long-term wearing. In particular, fabrics on the human body have to endure heat variation, moisture evaporation from metabolic activities, and even the immersion with body sweat. To face the above challenges, here we report a wool-knitted fabric sensor treated with graphene oxide (GO) dyeing followed by l-ascorbic acid (l-AA) reduction (rGO). This rGO-based strain sensor is highly stretchable, washable, and durable with rapid sensing response. It exhibits excellent linearity with more than 20% elongation and, most importantly, withstand moisture from 30 to 90% (or even immersed with water) and still maintains good electrical and mechanical properties. We further demonstrate that, by integrating this proposed material with the near-field communication (NFC) system, a batteryless, wireless wearable body movement sensor can be constructed. This material can find wide use in smart garment applications.

Improved proteomic analysis pipeline for LC-ETD-MS/MS using charge enhancing methods.

Electron transfer dissociation (ETD) is a useful and complementary activation method for peptide fragmentation in mass spectrometry. However, ETD spectra typically receive a relatively low score in the identifications of 2+ ions. To overcome this challenge, we, for the first time, systematically interrogated the benefits of combining ion charge enhancing methods (dimethylation, guanidination, m-nitrobenzyl alcohol (m-NBA) or Lys-C digestion) and differential search algorithms (Mascot, Sequest, OMSSA, pFind and X!Tandem). A simple sample (BSA) and a complex sample (AMJ2 cell lysate) were selected in benchmark tests. Clearly distinct outcomes were observed through different experimental protocol. In the analysis of AMJ2 cell lines, X!Tandem and pFind revealed 92.65% of identified spectra; m-NBA adduction led to a 5-10% increase in average charge state and the most significant increase in the number of successful identifications, and Lys-C treatment generated peptides carrying mostly triple charges. Based on the complementary identification results, we suggest that a combination of m-NBA and Lys-C strategies accompanied by X!Tandem and pFind can greatly improve ETD identification.