Nanoparticle-based nanocomposite coatings with postprocessing for enhanced antimicrobial capacity of polymeric film.

Bacterial adhesion and biofilm formation on surfaces pose a significant risk of microbial contamination and chronic diseases, leading to potential health complications. To mitigate this concern, the implementation of antibacterial coatings becomes paramount in reducing pathogen propagation on contaminated surfaces. To address this requirement, our study focuses on developing cost-effective and sustainable methods using polymer composite coatings. Copper and titanium dioxide nanoparticles were used to assess their active antimicrobial functions. After coating the surface with nanoparticles, four different combinations of two postprocessing treatments were performed. Intense pulsed light was utilized to sinter the coatings further, and plasma etching was applied to manipulate the physical properties of the nanocomposite-coated sheet surface. Bacterial viability was comparatively analyzed at four different time points (0, 30, 60, and 120 min) upon contact with the nanocomposite coatings. The samples with nanoparticle coatings and postprocessing treatments showed an above-average 84.82% mortality rate at 30 min and an average of 89.77% mortality rate at 120 min of contact. In contrast, the control sample, without nanoparticle coatings and postprocessing treatments, showed a 95% microbe viability after 120 min of contact. Through this study, we gained critical insights into effective strategies for preventing the spread of microorganisms on high-touch surfaces, thereby contributing to the advancement of sustainable antimicrobial coatings.

Manipulating mechanical properties of PEG-based hydrogel nanocomposite: A potential versatile bio-adhesive for the suture-less repair of tissue.

Multifunctional bio-adhesives with tunable mechanical properties are obtained by controlling the orientation of anisotropic particles in a blend of fast-curing hydrogel with an imposed capillary flow. The suspensions' microstructural evolution was monitored by the small-angle light scattering (SALS) method during flow up to the critical Péclet number (Pe≈1) necessary for particle orientation and hydrogel crosslinking. The multifunctional bio-adhesives were obtained by combining flow and UV light exposure for rapid photo-curing of PEGDA medium and freezing titania rods' ordered microstructures. Blending the low- and high-molecular weight of PEGDA polymer improved the mechanical properties of the final hydrogel. All the hydrogel samples were non-cytotoxic up to 72 h after cell culturing. The system shows rapid blood hemostasis and promotes adhesive and cohesive strength matching targeted tissue properties with an applicating methodology compatible with surgical conditions. The developed SALS approach to optimize nanoparticles' microstructures in bio-adhesive applies to virtually any optically transparent nanocomposite and any type of anisotropic nanoparticles. As such, this method enables rational design of bio-adhesives with enhanced anisotropic mechanical properties which can be tailored to potentially any type of tissue.

Visible light laser direct-writing of high-resolution, biocompatible, super-multifunctional and tough hydrogels without photoinitiators in 30 s.

Currently, the lack of bioinks and long printing time limits the further development of biofabrication. Here we report a novel biocompatible, multi-functional and tough 3D printable hydrogel via visible light photocrosslinking of polyvinyl alcohol bearing styrylpyridinium group (PVA-SbQ). The high-resolution PVA-SbQ hydrogels with different designed shapes can be generated via laser direct-writing in 30 s without extra toxic crosslinkers or photoinitiators, and demonstrates excellent biocompatibility. The rapid laser direct-writing technology also results in a super-strong, tough hydrogel with excellent adhesive, swelling, self-healing, and photo-tunable properties due to the photodimerization of styrylpyridinium (SbQ) groups and the left-over massive amount of free hydroxyl groups in the hydrogel. For example, the maximum tensile strength, elongation, compressive strength adhesive strength of printed PVA-SbQ hydrogels can reach 1.0 MPa, 810 %, 33 MPa, 31 kPa, and 25,000 % respectively. And these properties can be adjusted by controlling the parameters for laser direct-writing. In addition, the introduced nitrogen cations by SbQ groups further endow hydrogels with the potential to develop novel functionality, which is demonstrated by integrating negatively charged nanocelluloses in the PVA-SbQ system to develop underwater adhesives, anti-freezing (-24.9 °C), and anti-bacterial hydrogels. This discovery opens multiple doors for developing PVA-SbQ based multi-functional hydrogel for various applications including biofabrication and tissue engineering.

Polyether ether ketone surface modification with plasma and gelatin for enhancing cell attachment.

Polyether ether ketone (PEEK) has shown great promise for implant and biomedical applications because of its excellent chemical, mechanical, and biocompatible properties. However, PEEK is bioinert, which causes weak cell adhesion and limits its use for biomedical applications such as bone implants. Therefore, the activation of the PEEK's surface for cell attachment is desirable. In this study, oxygen plasma and gelatin were used to modify PEEK's surface and the effects of surface roughness, wettability, and cell adhesion to the surface were studied. Surface roughness was measured using a laser scanning confocal microscope, and wettability was measured using the sessile drop method. There was no significant difference in the roughness of the three samples. The gelatin-coated surface showed higher wettability than the plasma-modified or control samples. The cell attachment and proliferation rate were assessed by scanning electron microscopy and the XTT assay, respectively. The XTT assay results indicated that a greater number of cells grew on the gelatin-coated PEEK surface than on the control or plasma-treated surfaces. These results confirmed that the plasma and gelatin treatments enhanced the biocompatibility of the PEEK samples. The increase in biocompatibility could make PEEK a better material candidate for treating bone related injuries and defects.

A rapid near-patient detection system for SARS-CoV-2 using saliva.

The highly infectious nature of SARS-CoV-2 necessitates the use of widespread testing to control the spread of the virus. Presently, the standard molecular testing method (reverse transcriptase-polymerase chain reaction, RT-PCR) is restricted to the laboratory, time-consuming, and costly. This increases the turnaround time for getting test results. This study sought to develop a rapid, near-patient saliva-based test for COVID-19 (Saliva-Dry LAMP) with similar accuracy to that of standard RT-PCR tests. A lyophilized dual-target reverse transcription-loop-mediated isothermal amplification (RT-LAMP) test with fluorometric detection by the naked eye was developed. The assay relies on dry reagents that are room temperature stable. A device containing a centrifuge, heat block, and blue LED light system was manufactured to reduce the cost of performing the assay. This test has a limit of detection of 1 copy/µL and achieved a positive percent agreement of 100% [95% CI 88.43% to 100.0%] and a negative percent agreement of 96.7% [95% CI 82.78-99.92%] relative to a reference standard test. Saliva-Dry LAMP can be completed in 105 min. Precision, cross-reactivity, and interfering substances analysis met international regulatory standards. The combination of ease of sample collection, dry reagents, visual detection, low capital equipment cost, and excellent analytical sensitivity make Saliva-Dry LAMP particularly useful for resource-limited settings.

Stereolithography 3D Bioprinting.

Stereolithography (SLA) 3D bioprinting has emerged as a prominent bioprinting method addressing the requirements of complex tissue fabrication. This chapter addresses the advancement in SLA 3D bioprinting in concurrent with the development of novel photocrosslinkable biomaterials with enhanced physical and chemical properties. We discuss the cytocompatible photoinitiators operating in the wide spectrum of the ultraviolet (UV) and the visible light and high-resolution dynamic mask projection systems with a suitable illumination source. The potential of SLA 3D bioprinting has been explored in various themes, like bone and neural tissue engineering and in the development of controlled microenvironments to study cell behavior. The flexible design and versatility of SLA bioprinting makes it an attractive bioprinting process with myriad possibilities and clinical applications.