ACS Applied Nano Materials最新文献

In this study, hybrid coating systems comprising biopolymers (chitosan, N-succinyl chitosan, or sodium alginate, and sodium carboxymethylcellulose) and iron oxide nanoparticles (IONPs) were synthesized, and their antiviral activity against the coronavirus as well as their dermal toxicity in rats were evaluated. The hybrid systems were applied as coating surfaces with virucidal properties against the coronavirus. IONPs were synthesized by using the coprecipitation method, with TEM images revealing their crystalline structure and an average size of 5.6 nm. XRD analysis confirmed the predominance of magnetite in the nanoparticles. Zeta potential analysis assessed the suspension stability of the biopolymer-based antiviral solutions at different IONP concentrations (1.4, 2.8, and 4.1 mM). The hybrid systems were designed for coating cotton fabric, and SEM, EDS, and FTIR characterized the coated surfaces. Among the coatings, the N-succinyl chitosan-based (IONPs/NSC) coating showed the lowest iron ion release after 24 h compared to other polymers. The IONPs/NSC hybrid coating achieved 99% antiviral activity within 5 min of contact, and all coatings exhibited 99.9999% antiviral activity against coronavirus within 24 h, while being nontoxic to L929 fibroblast cells after 24 h of exposure. The acute dermal toxicity of the IONPs/NSC hybrid system was evaluated in accordance with OECD guidelines 402, demonstrating safety for topical use. For this, animals were treated with topical applications of increasing doses of IONPs/NSC (1.5, 5, 14, and 40 mg/kg), benzalkonium chloride (750 mg/kg, toxic standard), and saline or white nanoparticle (WN, control group or a polymeric solution without IONPs). Compared to the control group, no clinical or histological changes were observed for the IONPs/NSC groups during the 14-day observation period. Conversely, benzalkonium chloride induced erythema, edema, and histological alterations in rat skin. These coatings show promise for use on protective equipment, with the aim to mitigate the risk of epidemics or pandemics.

Three tetraphenylethene molecular cage-based polymers with blue, yellow, and red emission (TCPBs, TCPYs, and TCPRs) were synthesized through successive atom transfer radical polymerization (ATRP) reactions. In an aqueous solution, they exhibit aggregation-induced emission effects, resulting in blue, yellow, and red fluorescence respectively. These polymers can be combined to create stable white light emissive hybrid nanoparticles (TCPWs) through Freud resonance energy transfer (FRET) effects. The resulting TCPWs demonstrate excellent fluorescence stability and can serve as fluorescent probes for long-term intracellular imaging for as long as 10 passages (20 days), outperforming single fluorescence emissive probes.

Surface-enhanced Raman scattering (SERS) is a promising, sensitive, and label-free molecule detection scheme. However, uniformity and reproducibility of signal enhancement have remained elusive, making quantitative evaluation difficult. In this work, we propose a simple fabrication approach to quantitative SERS sensors that satisfies all the sought-after characteristics: a gold hole-sphere nanogap SERS substrate that is uniform, reproducible, sensitive, large, and cost-effective. Here, we achieve a sensing uniformity of 4.2% averaged over 4 points throughout the entire 6-in. substrate and a SERS enhancement of 4.6 × 10⁸. Our approach provides for gap control in the vertical direction, thus granting very precise control with subnanometer accuracy and the statistical distribution of nanospheres in plane. This combination enables a remarkably uniform and reproducible SERS sensitivity over the entire substrate. The SERS spectra from DNA bases are also measured and their corresponding peaks are well defined down to 10 pM concentration. The proposed approach should be a key to quantitative SERS.

Selenomethionine (SeM) holds great potential applications in tumor therapy. However, the tumor-targeting ability of SeM in vivo remains challenging. Herein, we utilize extracellular vesicles (EV) as tumor-targeted drug delivery systems to achieve enhanced specific targeting and antitumor efficacy. The carboxyl groups of SeM are conjugated with the amino groups of EV derived from low-pH culture medium reprogrammed CT26 cells (LEV) to obtain the SeM-based formulations (SMLEV), which can actively target tumor cells and enhance uptake efficacy through specific behaviors of LEV to their parent cells. Mechanistic studies indicate that SMLEV can induce reactive oxygen species (ROS) overproduction, mitochondrial dysfunction, as well as Caspase-9 and Caspase-3 activation. Here, SMLEV exhibit enhanced cytotoxic potential toward colon tumor (CT26) cells. After systemic administration, the growth of tumors is inhibited in vivo using CT26 tumor-bearing mice. Our findings can provide insights and a strategy in developing SeM delivery for tumor treatment.