Predictive Scoring System for Spontaneous Closure of Infant Ventricular Septal Defect: The P-VSD Score.

Ventricular septal defect (VSD) is a common congenital heart disease. However, consensus on the utility of echocardiography in predicting spontaneous closure (SC) of VSD remains lacking. This study aimed to identify and validate significant predictors of SC through a predictive scoring system. This retrospective study included medical records of 712 echocardiography instances performed on 304 patients diagnosed with VSD from 2016 to 2020 in their first year of life. A novel scoring system for predicting the SC of VSD was developed and validated using another dataset from different hospitals. Of the 304 patients, 215 (70.7%) had perimembranous (PM) VSDs and 89 had muscular (29.3%) VSDs. The median follow-up periods were 36.2 (interquartile range [IQR], 13-59) months and 13.7 9 (IQR, 5-37.4) days for PM and muscular VSDs, respectively. The overall SC rate during follow-up was 29.3%. Pulmonary hypertension (HTN), concomitant left ventricle (LV)-right atrium (RA) shunt, VSD size to aortic valve (AV) annulus size ratio, and left ventricular end-diastolic dimension (LVEDD) z-score were significant risk factors affecting SC of VSD. The "P-VSD" score, a new scoring system, demonstrated an area under the curve for predictability of 0.769. Pulmonary HTN, concomitant LV-RA shunt, LVEDD z-score, and VSD size-to-AV annulus size ratio at diagnosis were significantly associated with non-SC VSD after infancy. The P-VSD score can predict the SC of VSD in clinical settings and simplify the identification and appropriate management of high-risk patients.

DNA assembly and enzymatic cutting in solutions: a gold nanoparticle based SERS detection strategy.

The ability to monitor biomolecular recognition such as DNA hybridization and enzymatic reactivity in solutions with high sensitivity is important for developing effective bioassay strategies. Surface enhanced Raman scattering (SERS) based on use of solid substrates to produce the SERS effect for the detection often requires substrate preparation which is ineffective for rapid monitoring. This report describes a new strategy exploiting a gold nanoparticle (AuNP) based interparticle "hot-spot" for SERS monitoring of DNA mediated assembly and enzyme induced cleavage of the assembly in solution phase. The DNAs consist of two different complementary DNA strands with a thiol modification for attachment to AuNPs of selected sizes. In a solution containing AuNPs conjugated with one of the single-stranded (ss) DNA and other AuNPs labeled with a Raman reporter molecule, 4-mercaptobenzoic acid (MBA), the introduction of the complementary DNA strand leads to a linkage of the two types of AuNPs, producing double-stranded (ds) DNA-AuNP assembly (ds-DNA-AuNPs) with an interparticle "hot-spot" for SERS detection of the diagnostic bands of the reporter. Upon introducing a restriction enzyme (e.g. MspI) into the ds-DNA-AuNP assembly solution, the removal of the interparticle "hot-spot" due to restriction enzyme cleavage of the ds-DNA leads to a decrease of the SERS signals. While the detailed cleavage process may depend on the reaction time and the amount of enzyme, the viability of using gold nanoparticle "hot-spot" based SERS monitoring of DNA assembly and enzyme cleavage is clearly demonstrated, which has important implications for developing new strategies for bioassays.

MicroRNA conjugated gold nanoparticles and cell transfection.

While the importance of microRNAs (miRNAs) in cancer treatment or manipulation of genetic expression has been increasingly recognized for developing miRNA-based therapies, the controlled delivery of miRNAs into specific cells constitutes a challenging task. This report describes preliminary findings from an investigation of the conjugation of gold nanoparticles with miRNAs (miRNA-AuNPs) and their cell transfection. The immobilization of miRNAs on the AuNPs was detected, and the surface stability was substantiated by gel electrophoresis assessment of the highly charged characteristics of miRNA-AuNPs and their surface-exchange inactivity with a highly charged surfactant. The miRNA-AuNPs were tested in cell transfection using multiple myeloma cells, demonstrating efficient knockdown in the functional luciferase assay. The findings have important implications for understanding the mechanistic details of cell transfection involving miRNA-conjugated nanoparticles as biosensing or targeting probes.