Polymer Microspheres Copolymerized with Deep Red Fluorescent Molecules as a Label for Lateral Flow Immunochromatography.

The development of fluorescently labeled microspheres is a critical aspect of advancing the technology of lateral flow immunochromatography (LFIA) for biological detection. Nevertheless, potential interference posed by the background fluorescence originating from the nitrocellulose (NC) membrane would significantly impact the sensitivity and accuracy of microsphere-based detection in LFIA. In this work, an attempt was made to extend the π-conjugated system and asymmetric structure of rhodamine fluorophore, resulting in the synthesis of dye molecules (RB2) incorporating double bonds, which can reach an absolute photoluminescence quantum yield (PLQY) of 30.01% in EtOH. Subsequently, carboxyl group functionalized fluorescent microspheres were prepared in a two-step copolymerization via soap-free emulsion polymerization. The obtained microspheres were characterized by scanning electron microscopy, transmission electron microscopy, DLS, Fourier transform infrared spectroscopy, ultraviolet spectrophotometry, and fluorescence spectrophotometry. The results showed that RB2 was successfully copolymerized into the microspheres, and the resulting microspheres had good dispersion and stability with high red fluorescence intensity (λabs ∼ 610 nm, λem ∼ 660 nm). Utilizing these microspheres, the resulting lateral flow immunoassay was successfully found to detect SARS-CoV-2 N protein with a detection limit of 2.5 pg/mL and the linear concentration spanning from 2.5 pg/mL to 10 ng/mL. The results confirm the effectiveness of the synthetic fluorescent microspheres as the label for LFIA.

Biomaterials and tissue engineering in traumatic brain injury: novel perspectives on promoting neural regeneration.

Traumatic brain injury is a serious medical condition that can be attributed to falls, motor vehicle accidents, sports injuries and acts of violence, causing a series of neural injuries and neuropsychiatric symptoms. However, limited accessibility to the injury sites, complicated histological and anatomical structure, intricate cellular and extracellular milieu, lack of regenerative capacity in the native cells, vast variety of damage routes, and the insufficient time available for treatment have restricted the widespread application of several therapeutic methods in cases of central nervous system injury. Tissue engineering and regenerative medicine have emerged as innovative approaches in the field of nerve regeneration. By combining biomaterials, stem cells, and growth factors, these approaches have provided a platform for developing effective treatments for neural injuries, which can offer the potential to restore neural function, improve patient outcomes, and reduce the need for drugs and invasive surgical procedures. Biomaterials have shown advantages in promoting neural development, inhibiting glial scar formation, and providing a suitable biomimetic neural microenvironment, which makes their application promising in the field of neural regeneration. For instance, bioactive scaffolds loaded with stem cells can provide a biocompatible and biodegradable milieu. Furthermore, stem cells-derived exosomes combine the advantages of stem cells, avoid the risk of immune rejection, cooperate with biomaterials to enhance their biological functions, and exert stable functions, thereby inducing angiogenesis and neural regeneration in patients with traumatic brain injury and promoting the recovery of brain function. Unfortunately, biomaterials have shown positive effects in the laboratory, but when similar materials are used in clinical studies of human central nervous system regeneration, their efficacy is unsatisfactory. Here, we review the characteristics and properties of various bioactive materials, followed by the introduction of applications based on biochemistry and cell molecules, and discuss the emerging role of biomaterials in promoting neural regeneration. Further, we summarize the adaptive biomaterials infused with exosomes produced from stem cells and stem cells themselves for the treatment of traumatic brain injury. Finally, we present the main limitations of biomaterials for the treatment of traumatic brain injury and offer insights into their future potential.

The protective effect of syringic acid on dextran sulfate sodium-induced experimental colitis in BALB/c mice.

Inflammatory bowel diseases involve chronic intestinal inflammation which is mostly caused by Crohn's disease and ulcerative colitis (UC) conditions. Patients having UC are prone to colorectal cancer and dysplastic polyps, and also have sporadic adenomas. Syringic acid (SA) possesses many health benefits including antioxidant, anti-bacterial, and anti-cancer. This study was aimed to identify the effects of SA on UC, using a murine experimental model. Clinical symptoms and weight loss were significantly reduced in mice induced with dextran sulfate sodium (DSS) and treated with SA, compared to untreated mice. The effects of SA exhibited in DSS-induced mice were associated with significant decrease in the expressions levels of inflammatory mediators such as inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), pro-inflammatory cytokines (tumor necrosis factor [TNF-α], interleukin [IL-1ß and IL-6]), remarkable amelioration of colonic architectural disruption, and a significant reduction in the activity of colonic myeloperoxidase. To further confirm the anti-inflammatory property of SA, RAW 264.7 cells were stimulated with lipopolysaccharides. SA dose-dependently inhibited the cytokines TNF-α, IL-1ß, and IL-6. It also decreased the expressions of p65-NF-κB and IκB, thus reducing the activation and nuclear accumulation of p-STAT-3Y705 . This prohibited the degradation of inhibitory protein, IκB, as well as inhibited the nuclear translocation of p65-NF-κB in colonic tissue. It was concluded that SA has a potential to limit inflammation via inhibiting the p65-NF-κB and STAT3 signaling; hence it can be used for therapeutic purposes.

A note on the empirical likelihood confidence band for hazards ratio with covariate adjustment.

In medical studies comparing two treatments in the presence of censored data, the stratified Cox model is an important tool that has the ability to flexibly handle non-proportional hazards while allowing parsimonious covariate adjustment. In order to capture the cumulative treatment effect, the ratio of the treatment specific cumulative baseline hazards is often used as a measure of the treatment effect. Pointwise and simultaneous confidence bands associated with the estimated ratio provide a global picture of how the treatment effect evolves over time. Recently, Dong and Matthews (2012, Biometrics 68, 408-418) proposed to construct a pointwise confidence interval for the ratio using a plug-in type empirical likelihood approach. However, their result on the limiting distribution of the empirical likelihood ratio is generally incorrect and the resulting confidence interval is asymptotically undercovering. In this article, we derive the correct limiting distribution for the likelihood ratio statistic. We also present simulation studies to demonstrate the effectiveness of our approach.

Early results of 18 adults, following a modified Nuss operation for recurrent pectus excavatum.

OBJECTIVES: The minimally-invasive Nuss operation has been widely used for correcting pectus excavatum in children. However, a number of adult patients require reoperations for recurrence or other complications. This work aimed to investigate the early results of recurrent pectus excavatum repair using a modified Nuss procedure, which were seldom reported in adult patients. METHODS: A retrospective chart review was conducted on 18 adult patients who underwent modified Nuss procedure in the age range of 18-31 years. The Haller index of the patients ranged from 3.2 to 6.5. In the modified Nuss technique, a small auxiliary incision was made below the xiphoid process and one finger was inserted instead of a thoracoscope. The introducer was guided by the finger, slowly advanced across the mediastinum and raised the sternum and the anterior chest wall to the desired position. The Lorenz correction bar was introduced through the tunnel, placed in position, and turned over so that the convexity faced anteriorly. RESULTS: The operations were performed successfully and no operative mortality occurred. The mean operating time was 68.5 ± 15.5 min. The postoperative results were excellent in 77.8% of patients and good in 22.2%. Early complications were mild and no late complications occurred. CONCLUSIONS: The modified Nuss procedure is an excellent reoperative correction for adult patients and has outstanding early results, considering that it is technically challenging.