Molecular imaging of oxidative stress using an LED-based photoacoustic imaging system.

LED-based photoacoustic imaging has practical value in that it is affordable and rugged; however, this technology has largely been confined to anatomic imaging with limited applications into functional or molecular imaging. Here, we report molecular imaging reactive oxygen and nitrogen species (RONS) with a near-infrared (NIR) absorbing small molecule (CyBA) and LED-based photoacoustic imaging equipment. CyBA produces increasing photoacoustic signal in response to peroxynitrite (ONOO-) and hydrogen peroxide (H2O2) with photoacoustic signal increases of 3.54 and 4.23-fold at 50 µM of RONS at 700 nm, respectively. CyBA is insensitive to OCl-, ˙NO, NO2-, NO3-, tBuOOH, O2-, C4H9O˙, HNO, and ˙OH, but can detect ONOO- in whole blood and plasma. CyBA was then used to detect endogenous RONS in macrophage RAW 246.7 cells as well as a rodent model; these results were confirmed with fluorescence microscopy. Importantly, CyB suffers photobleaching under a Nd:YAG laser but the signal decrease is <2% with the low-power LED-based photoacoustic system and the same radiant exposure time. To the best of our knowledge, this is the first report to describe molecular imaging with an LED-based photoacoustic scanner. This study not only reveals the sensitive photoacoustic detection of RONS but also highlights the utility of LED-based photoacoustic imaging

Postnatal growth and short-term complications in very low birth weight neonates receiving total parenteral nutrition

Objective: To study the postnatal growth and short-term complications in very low birth weight preterm neonates receiving totalparenteral nutrition (TPN). Methods: This prospective, observational study was conducted in the neonatal intensive care unit ofa tertiary care hospital in South India. All neonates with birth weight <1250 g and <32 weeks of gestation who received TPNand survived at least 7 days were studied prospectively. Amino acid infusion was started at 1 g/kg/day on day 1 and graded up to4 g/kg/day. Lipids were started on the day 2 of life at 1 g/kg/day and graded up to 3 g/kg/day. Enteral feeds were introduced within3 days of life. TPN was stopped once enteral feeds reached 100 ml/kg/day. Postnatal growth and biochemical and hematologicalparameters were also monitored. Results: Time to reach full enteral feeds was 11.3±4.5 days, cumulative weight loss proportion(in %) was 8.5±4.7, and number of days to regain birth weight was 11.1±4.5 days. Mean growth velocity (GV) at 30 days of lifeand 40 weeks of postmenstrual age (PMA) was 16.37±4.8 g/kg/day and 20.03±5.8 g/day, respectively. Mean GV of appropriatefor gestational age (AGA) infants was 3.13 g/kg/day, lower compared to small for GA (SGA) infants at 30 days PMA (p=0.01).However, there was no statistical difference in GV between AGA and SGA infants at 40 weeks of PMA. There was no correlationbetween energy intake on the day 7 and weight and head circumference at 40 weeks of PMA. Hyponatremia was observed in 40.6%infants receiving TPN, and there were no other significant complications. Conclusion: Conventional TPN was associated withfavorable postnatal growth until 30 days of postnatal life. However, catch-up growth at 40 weeks of PMA was not satisfactory. MeanGV of AGA infants was found to be lower compared to that in SGA infants at 30 days of postnatal life. Besides hyponatremia, therewas no major complication due to TPN in this study

Association of VACTERL with truncus arteriosus, left-sided aortic arch, hypoplastic pulmonary arteries, and severe radial axis defect

Background: VACTERL association is usually a sporadic disorder, the possible etiologies of which have been proposed as familial as well as multiple genetic and environmental factors. VACTERL association usually consists of at least three of the core features of vertebral defects, anal atresia, cardiac defects, tracheoesophageal fistula, renal anomalies, and limb abnormalities. Vertebral anomalies, cardiac malformations, renal anomalies, and limb malformations have been reported to occur in 60-80%, 40-80%, 50-80%, and 40-50% of the patients, respectively. Among the cardiac anomalies, ventricular septal defect is the most prevalent one. Truncus arteriosus is a rarely associated defect. The radial anomalies are the most classic limb defects with different severity levels (types I-IV). Although radial axis defect usually accompanies this association, complete absence of radius is reported only in one third of the cases. Case report: In this case study, we reported a neonate having this association consisting of severe cyanotic congenital heart defect (truncus arteriosus) and unilateral type IV radial aplasia. Conclusion: VACTERL association components can have various new findings

White light emitting polymers from a luminogen with local polarity induced enhanced emission

Aggregation induced enhanced emission (AIEE) is considered as an important tool to circumvent the aggregation caused quenching (ACQ) effect in organic light emitting diodes (OLEDs). Charge trapping and surplus long wavelength electroluminescence is a cause of concern in single polymer based white OLEDs. However, the potential of luminogens with AIEE property as a credible tool to offset the above problems in white light emitting single polymer is not properly explored. In this study design, synthesis and spectral characterization of a polymerizable luminogen, (2Z,2′Z)-6,6′-(2,7-dibromo-9H-fluorene-9,9-diyl)bis(hexane-6,1-diyl)bis(2-cyano-3-(10-hexyl-10H-phenothiazin-3-yl)acrylate(FCPA) with AIEE property and its copolymers is presented. Lippert-Mataga studies showed that reduced local polarity caused by aliphatic chains in condensed state of FCPA resulted in AIEE property. The copolymers P(FCPA-1) and P(FCPA-0.5) with 1% and 0.5% FCPA moieties showed white electroluminescence and enhanced thin film photoluminescence that matched very closely. The superior performance of OLEDs is attributed to the presence of a phenothiazine group in FCPA that resulted in nearly equal electron and hole injection barriers

Molecular imaging of oxidative stress using an LED-based photoacoustic imaging system.

LED-based photoacoustic imaging has practical value in that it is affordable and rugged; however, this technology has largely been confined to anatomic imaging with limited applications into functional or molecular imaging. Here, we report molecular imaging reactive oxygen and nitrogen species (RONS) with a near-infrared (NIR) absorbing small molecule (CyBA) and LED-based photoacoustic imaging equipment. CyBA produces increasing photoacoustic signal in response to peroxynitrite (ONOO-) and hydrogen peroxide (H2O2) with photoacoustic signal increases of 3.54 and 4.23-fold at 50 µM of RONS at 700 nm, respectively. CyBA is insensitive to OCl-, ˙NO, NO2-, NO3-, tBuOOH, O2-, C4H9O˙, HNO, and ˙OH, but can detect ONOO- in whole blood and plasma. CyBA was then used to detect endogenous RONS in macrophage RAW 246.7 cells as well as a rodent model; these results were confirmed with fluorescence microscopy. Importantly, CyB suffers photobleaching under a Nd:YAG laser but the signal decrease is <2% with the low-power LED-based photoacoustic system and the same radiant exposure time. To the best of our knowledge, this is the first report to describe molecular imaging with an LED-based photoacoustic scanner. This study not only reveals the sensitive photoacoustic detection of RONS but also highlights the utility of LED-based photoacoustic imaging

White Light Emitting Polymers from a Luminogen with Local Polarity Induced Enhanced Emission

Aggregation induced enhanced emission (AIEE) is considered as an important tool to circumvent the aggregation caused quenching (ACQ) effect in organic light emitting diodes (OLEDs). Charge trapping and surplus long wavelength electroluminescence is a cause of concern in single polymer based white OLEDs. However, the potential of luminogens with AIEE property as a credible tool to offset the above problems in white light emitting single polymer is not properly explored. In this study design, synthesis and spectral characterization of a polymerizable luminogen, (2<i>Z</i>,2′<i>Z</i>)-6,6′-(2,7-dibromo-9<i>H</i>-fluorene-9,9-diyl)­bis­(hexane-6,1-diyl)­bis­(2-cyano-3-(10-hexyl-10<i>H</i>-phenothiazin-3-yl)­acrylate­(FCPA) with AIEE property and its copolymers is presented. Lippert-Mataga studies showed that reduced local polarity caused by aliphatic chains in condensed state of FCPA resulted in AIEE property. The copolymers P­(FCPA-1) and P­(FCPA-0.5) with 1% and 0.5% FCPA moieties showed white electroluminescence and enhanced thin film photoluminescence that matched very closely. The superior performance of OLEDs is attributed to the presence of a phenothiazine group in FCPA that resulted in nearly equal electron and hole injection barriers

A cellulose-based photoacoustic sensor to measure heparin concentration and activity in human blood samples

Heparin is an indispensable drug in anticoagulation therapy but with a narrow therapeutic window, which dictates regular testing and dose adjustment. However, current monitoring tools have a long turnaround time or are operator intensive. In this work, we describe a cellulose-based photoacoustic sensor for heparin. The sensors have a turnaround time of 6 min for whole blood samples and 3 min for plasma samples regardless of heparin concentration. These sensors have a limit of detection of 0.28 U/ml heparin in human plasma and 0.29 U/ml in whole blood with a linear response (Pearson's r = 0.99) from 0 to 2 U/ml heparin in plasma and blood samples. The relative standard deviation was &lt; 12.5% in plasma and &lt; 17.5% in whole blood. This approach was validated with heparin-spiked whole human blood and had a linear correlation with the activated partial thromboplastin time (aPTT) (r = 0.99). We then studied 16 sets of clinical samples-these had a linear correlation with the activated clotting time (ACT) (Pearson's r = 0.86, P &lt; 0.0001). The photoacoustic signal was also validated against the cumulative heparin dose (Pearson's r = 0.71, P &lt; 0.0001). This approach could have applications in bed-side heparin assays for continuous heparin monitoring

Organosilica Nanoparticles with an Intrinsic Secondary Amine: An Efficient and Reusable Adsorbent for Dyes

Nanomaterials are promising tools in water remediation because of their large surface area and unique properties compared to bulky materials. We synthesized an organosilica nanoparticle (OSNP) and tuned its composition for anionic dye removal. The adsorption mechanisms are electrostatic attraction and hydrogen bonding between the amine on OSNP and the dye, and the surface charge of the OSNP can be tuned to adsorb either anionic or cationic dyes. Using phenol red as a model dye, we studied the effect of the amine group, pH, ionic strength, time, dye concentration, and nanomaterial mass on the adsorption. The theoretical maximum adsorption capacity was calculated to be 175.44 mg/g (0.47 mmol/g), which is higher than 67 out of 77 reported adsorbents. The experimental maximum adsorption capacity is around 201 mg/g (0.53 mmol/g). Furthermore, the nanoparticles are highly reusable and show stable dye removal and recovery efficiency over at least 10 cycles. In summary, the novel adsorbent system derived from the intrinsic amine group within the frame of OSNP are reusable and tunable for anionic or cationic dyes with high adsorption capacity and fast adsorption. These materials may also have utility in drug delivery or as a carrier for imaging agents