Bilirubin Absorption Spectrum Research Articles

Phototherapy to Prevent Severe Neonatal Hyperbilirubinemia in the Newborn Infant 35 or More Weeks of Gestation: Technical Report.

To summarize the principles and application of phototherapy consistent with the current 2022 American Academy of Pediatrics "Clinical Practice Guideline Revision for the Management of Hyperbilirubinemia in the Newborn Infant 35 or More Weeks of Gestation." Relevant literature was reviewed regarding phototherapy devices in the United States, specifically those that incorporate blue to blue-green light-emitting diode, fluorescent, halogen, or fiberoptic light sources, and their currently marketed indications. The efficacy of phototherapy devices varies widely because of nonstandardized use of light sources and configurations and irradiance meters. In summary, the most effective and safest devices have the following characteristics: (1) incorporation of narrow band blue-to-green light-emitting diode lamps (∼460-490 nm wavelength range; 478 nm optimal) that would best overlap the bilirubin absorption spectrum; (2) emission of irradiance of at least 30 µW/cm2/nm (in term infants); and (3) illumination of the exposed maximal body surface area of an infant (35% to 80%). Furthermore, accurate irradiance measurements should be performed using the appropriate irradiance meter calibrated for the wavelength range delivered by the phototherapy device. With proper administration of effective phototherapy to an infant without concurrent hemolysis, total serum or plasma bilirubin concentrations will decrease within the first 4 to 6 hours of initiation safely and effectively.

ZnS nanocrystallites as fluorescent probe for selective detection of bilirubin

Selective determination of bilirubin is much essential to identify neonatal hyperbilirubinemia. Herein, we present a simple and precise method for quantitative measuring of bilirubin levels using polyvinylpyrrolidone (PVP) capped ZnS nanocrystallites (ZSP). The crystalline structure and purity are studied from x-ray diffraction (XRD) patterns and the transmission electron microscope (TEM) images. The optical characteristics are analyzed using UV-visible absorption and photoluminescence spectra. For ZSP, the estimated value for the optical band gap is 4.06 eV, surpassing the band gap value of uncapped ZnS (3.89 eV). Upon 265 nm excitation, ZSP nanocrystallites exhibits blue emission peaked at 371 nm wavelength. The fluorescence intensity shows a consistent reduction as the bilirubin concentration rises from 3.0 μM to 80 μM. The spectral overlap between the emission spectrum of ZSP and the absorption spectrum of bilirubin, results in fluorescence attenuation due to the inner filter effect (IFE). The ZnS nanocrystallites exhibit remarkable fluorescence properties and demonstrate high sensitivity in detecting bilirubin, achieving a limit of detection (L.O.D) as low as 56 nM. The selectivity of bilirubin over certain co-existing biomolecules is also analyzed. The utility of the fluorescence probe for practical use is confirmed in spiked human serum and urine samples.

White LED phototherapy as an improved treatment for neonatal jaundice.

With the aim of improving phototherapy for neonatal jaundice (hyperbilirubinemia), this study investigates the degradation of unconjugated bilirubin under irradiance by conventional light and by white, red, green, and blue LED sources in vitro. The absorption spectra of bilirubin under these different light sources are compared. The results demonstrate that white LED phototherapy promotes more efficient bilirubin degradation than conventional blue-light therapy. This study provides a basis for the design of novel phototherapy devices for the treatment of hyperbilirubinemia.

Hemolysis Detection in Sub-Microliter Volumes of Blood Plasma

Hemolysis is one of the main reasons for blood sample rejection in clinical laboratories. The scope of this study is to develop a simple, sensitive, and cost-effective method for hemolysis detection in presence of interferants like bilirubin, and lipids in sub-microliter volumes of blood plasma. Experimental samples were prepared in plasma extracted from whole blood. These samples were typically mixtures of hemoglobin, bilirubin, and lipids of varying concentrations. A multispectral optical setup was devised to probe these samples without any optical filters or moving parts. The hemoglobin content in the samples were measured within the range of 0mg/dL to 400 mg/dL concentration using <1μL of detection volume. Detection sensitivity of >90% accuracy and ∼10% coefficient of variation across 27 unknown samples. The optical attenuation path length used was merely ∼150 micrometers. The spectral interference due to overlapping absorption spectrum of bilirubin and scattering spectrum of lipids are resolved using linear matrix algebra algorithms. Hemolysis can lead to spurious measurements of key clinical parameters such as Potassium, Lactate Dehydrogenase, Aspartic Acid Transferase, and other diagnostic biomarkers. Commonly used visual inspection of blood plasma coloration is prone to variability. Description of the sample preparation, calibration and verification of the experimental setup and linear matrix algebra algorithm for analyte interference determination is reported here. Owing to the sub-microliter detection volume and high sensitivity, the system has realistic potential to be implemented in point of care medical devices that demands such low volumes of clinical specimen.

Spectral matching research for light-emitting diode-based neonatal jaundice therapeutic device light source

To decrease the risk of bilirubin encephalopathy and minimize the need for exchange transfusions, we report a novel design for light source of light-emitting diode (LED)-based neonatal jaundice therapeutic device (NJTD). The bilirubin absorption spectrum in vivo was regarded as target. Based on spectral constructing theory, we used commercially available LEDs with different peak wavelengths and full width at half maximum as matching light sources. Simple genetic algorithm was first proposed as the spectral matching method. The required LEDs number at each peak wavelength was calculated, and then, the commercial light source sample model of the device was fabricated to confirm the spectral matching technology. In addition, the corresponding spectrum was measured and the effect was analyzed finally. The results showed that fitted spectrum was very similar to the target spectrum with 98.86 % matching degree, and the actual device model has a spectrum close to the target with 96.02 % matching degree. With higher fitting degree and efficiency, this matching algorithm is very suitable for light source matching technology of LED-based spectral distribution, and bilirubin absorption spectrum in vivo will be auspicious candidate for the target spectrum of new LED-based NJTD light source.

Spectral matching technology for light-emitting diode-based jaundice photodynamic therapy device

The objective of this paper is to obtain the spectrum of light-emitting diode (LED)-based jaundice photodynamic therapy device (JPTD), the bilirubin absorption spectrum in vivo was regarded as target spectrum. According to the spectral constructing theory, a simple genetic algorithm as the spectral matching algorithm was first proposed in this study. The optimal combination ratios of LEDs were obtained, and the required LEDs number was then calculated. Meanwhile, the algorithm was compared with the existing spectral matching algorithms. The results show that this algorithm runs faster with higher efficiency, the switching time consumed is 2.06 s, and the fitting spectrum is very similar to the target spectrum with 98.15% matching degree. Thus, blue LED-based JPTD can replace traditional blue fluorescent tube, the spectral matching technology that has been put forward can be applied to the light source spectral matching for jaundice photodynamic therapy and other medical phototherapy.

Current State and Prospects for Development of Systems for Photodynamic Therapy of Neonatal Hyperbilirubinemia

Detailed analysis of the current status and prospects of development of devices for phototherapy of neonatal hyper-bilirubinemia (jaundice) is discussed. It is shown that the presence in the emission spectrum of ultraviolet and infrared lamps of components absent in the absorption spectrum of bilirubin led to adverse side effects on neonates. It is shown that both in terms of improving the efficacy of phototherapy and reducing the adverse effects, as well as increasing the reliability and ease of use, there is no alternative to super-bright LED sources emitting in blue and blue-green spectral range for the treatment of neonatal jaundice.

Phototherapy to Prevent Severe Neonatal Hyperbilirubinemia in the Newborn Infant 35 or More Weeks of Gestation

To standardize the use of phototherapy consistent with the American Academy of Pediatrics clinical practice guideline for the management of hyperbilirubinemia in the newborn infant 35 or more weeks of gestation. Relevant literature was reviewed. Phototherapy devices currently marketed in the United States that incorporate fluorescent, halogen, fiber-optic, or blue light-emitting diode light sources were assessed in the laboratory. The efficacy of phototherapy units varies widely because of differences in light source and configuration. The following characteristics of a device contribute to its effectiveness: (1) emission of light in the blue-to-green range that overlaps the in vivo plasma bilirubin absorption spectrum (~460-490 nm); (2) irradiance of at least 30 μW · cm(-2) · nm(-1) (confirmed with an appropriate irradiance meter calibrated over the appropriate wavelength range); (3) illumination of maximal body surface; and (4) demonstration of a decrease in total bilirubin concentrations during the first 4 to 6 hours of exposure. RECOMMENDATIONS (SEE APPENDIX FOR GRADING DEFINITION): The intensity and spectral output of phototherapy devices is useful in predicting potential effectiveness in treating hyperbilirubinemia (group B recommendation). Clinical effectiveness should be evaluated before and monitored during use (group B recommendation). Blocking the light source or reducing exposed body surface should be avoided (group B recommendation). Standardization of irradiance meters, improvements in device design, and lower-upper limits of light intensity for phototherapy units merit further study. Comparing the in vivo performance of devices is not practical, in general, and alternative procedures need to be explored.

Analysis of wavelength-dependent photoisomerization quantum yields in bilirubins by fitting two exciton absorption bands

The absorption spectra of bilirubins were deconvoluted by two Gaussian curves of equal width representing the exciton bands of the non-degenerate molecular system. The two bands were used to study the wavelength dependence of the (4Z, 15Z) → (4Z, 15E) configurational photoisomerization quantum yield of the bichromophoric bilirubin-IXα (BR-IX), the intrinsically asymmetric bile pigment associated with jaundice and the symmetrically substituted bilirubins (bilirubin-IIIα and mesobilirubin-XIIIα), when they are irradiated in aqueous solution bound to human serum albumin (HSA). The same study was performed for BR-IX in ammoniacal methanol solution (NH4OH/MeOH). The quantum yields of the configurational photoprocesses were fitted with a combination function of the two Gaussian bands normalized to the total absorption, using the proportionality coefficients and a scaling factor as parameters. The decrease of the (4Z, 15Z) → (4Z, 15E) quantum yield with increasing wavelength, which occurs for wavelengths longer than the most probable Franck–Condon transition of the molecule, did not result in a unique function of the exciton absorptions. In particular we found two ranges corresponding to different exciton interactions with different proportionality coefficients and scaling factors. The wavelength-dependent photoisomerization of bilirubins was described as an abrupt change in quantum yield as soon as the resulting excitation was strongly localized in each chromophore. The change was correlated to a variation of the interaction between the two chromophores when the short-wavelength exciton absorption became vanishingly small. With the help of the circular dichroism (CD) spectrum of BR-IX in HSA, a small band was resolved in the bilirubin absorption spectrum, delivering part of the energy required for the (4Z, 15Z) → (4Z, 15E) photoisomerization of the molecule.

Bilirubin binding properties of pigeon serum albumin and its comparison with human serum albumin

Binding of bilirubin (BR) to pigeon serum albumin (PgSA) was studied by absorption, fluorescence and CD spectroscopy and results were compared with those obtained with human serum albumin (HSA). PgSA was found to be structurally similar to HSA as judged by near- and far-UV CD spectra. However, PgSA lacks tryptophan. Binding of BR to PgSA showed relatively weaker interaction compared to HSA in terms of binding affinity, induced red shift in the absorption spectrum of BR and CD spectral characteristics of BR–albumin complexes. Photoirradiation results of BR–albumin complexes also showed PgSA-bound BR more labile compared to HSA-bound BR.

Spectroscopic studies and normal coordinate analysis of bilirubin

The infrared spectrum of bilirubin has been recorded in the spectral region 200–4000 cm −1. The Raman spectrum has also been recorded using the second harmonic (530 nm) radiation of a 200 mW Nd-YAG laser. In order to confirm the vibrational assignment of the bands obtained from experimental observation, a normal coordinate analysis has been carried out using the semi-empirical AM1 method through mopac 5.1 computer program. Electronic absorption spectrum of bilirubin dissolved in CHCl 3 has been recorded in the spectral region 300–600 nm. A broad spectrum is observed with peak maxima at 454.2 nm. The photoacoustic spectrum of this molecule (in the powder form) has also been recorded for the first time which shows certain discrete features.

Comparison of the efficacy of conventional special blue light phototherapy and fiberoptic phototherapy in the management of neonatal hyperbilirubinaemia

The efficacy and usefulness of two types of phototherapy differing in the source, wavelength and irradiance of the light, conventional phototherapy consisting of special blue light and fiberoptic phototherapy, were compared in a relatively larger series of term newborns with non‐haemolytic and more significant hyperbilirubinaemia than those in previous studies. In total, 108 newborns were allocated sequentially to receive either conventional phototherapy consisting of five special blue lamps or fiberoptic phototherapy. The average spectral irradiance measured at the skin surface level of newborns during the study period was significantly greater in the conventional phototherapy group. The special blue lamp of the conventional phototherapy unit had an emission spectrum almost identical to the bilirubin absorption spectrum, whereas the tungsten‐halogen lamp of the fiberoptic phototherapy had a broad emission through the blue and green wavelengths (mainly in the green spectrum). Phototherapy was more effective in the conventional phototherapy group; the duration of exposure to phototherapy (h) was significantly shorter, and the overall bilirubin decline rate (as μmol/l/h and %/h) was significantly greater in the conventional phototherapy group. According to the nursing personnel, fiberoptic phototherapy was more comfortable than the conventional phototherapy frame because of the easier accessibility and handling of the infants during phototherapy. They complained of giddiness, nausea, glare, temporary blurring of vision and difficulty in detecting the skin colour changes of newborns with the blue light of the conventional phototherapy unit. Conventional phototherapy consisting of special blue fluorescent lamps with approximately twofold higher irradiance and an emission spectrum almost identical to the bilirubin absorption spectrum is preferable to fiberoptic phototherapy in the standard treatment of term newborns with non‐haemolytic hyperbilirubinaemia.

Binding of biliverdin, bilirubin, and thyroid hormones to lipocalin-type prostaglandin D synthase.

Lipocalin-type prostaglandin D synthase is a major protein of the cerebrospinal fluid and was originally known as beta-trace. We investigated the binding ability of prostaglandin D synthase toward bile pigments, thyroid hormones, steroid hormones, and fatty acids in this present study. We found that the recombinant enzyme binds bile pigments and thyroid hormones, resulting in quenching of the intrinsic tryptophan fluorescence, the appearance of induced circular dichroism of the lipophilic ligands, and a red shift of the absorption spectra of bilirubin and biliverdin. The binding of prostaglandin D synthase to lipophilic ligands was also demonstrated by the resonant mirror technique and surface plasmon resonance detection. The dissociation constants were calculated to be 33 nM, 37 nM, 660 nM, 820 nM, and 2.08 microM for biliverdin, bilirubin, L-thyroxine, 3,3',5'-triiodo-L-thyronine, and 3,3', 5-triiodo-L-thyronine, respectively. Biliverdin and bilirubin underwent a shift in their absorption peaks from 375 to 380 nm and from 439 to 446 nm, respectively, after binding to prostaglandin D synthase. Bilirubin bound to the enzyme showed a bisignate CD spectrum with a (-) Cotton effect at 422 nm and a (+) Cotton effect at 472 nm, indicating a right-handed chirality. The ligands also inhibited prostaglandin D synthase activity noncompetitively in a concentration-dependent manner, with IC50 values between 3.9 and 10. 9 microM. Epididymal retinoic acid-binding protein and beta-lactoglobulin, two other lipocalin proteins that bind retinoids such as prostaglandin D synthase, did not show any significant interaction with bile pigments or thyroid hormones. These results show that prostaglandin D synthase binds small lipophilic ligands with a specificity distinct from that of other lipocalins.

Light-emitting diodes: a novel light source for phototherapy.

High intensity light-emitting diodes (LEDs) are being studied as possible light sources for the phototherapy of hyperbilirubinemic neonates. These power-efficient, low heat-producing light sources have the potential to deliver high intensity light of narrow wavelength band in the blue-green portion of the visible light spectrum, which overlaps the absorption spectrum of bilirubin (BR). We compared the efficacy between single LEDs of different color and then constructed a prototype phototherapy device using 300 blue LEDs. The efficacy of this device was compared with that of conventional phototherapy devices by measuring the in vitro photodegradation of BR in human serum albumin. When blue, blue-green, green, and white LEDs were compared, the blue light was the most effective in degrading BR by 28% of dark control, followed by blue-green (18% of control), and then white light (14% of control). Green light was the least effective (11% of control). The prototype device with three focused arrays, each with 100 blue LEDs, generated greater irradiance (> 200 microW.cm-2.nm-1) than any of the conventional devices tested. It also supported the greatest rate of BR photodegradation. We conclude that light from LEDs should be considered a more effective treatment for hyperbilirubinemia than light from presently used phototherapy devices. Furthermore, the unique characteristics of this light source may make it especially suitable for use in safe and lightweight home phototherapy devices.

Single-strand breaks in the DNA of human cells exposed to visible light from phototherapy lamps in the presence and absence of bilirubin

Clinical evidence indicates that phototherapy of hyperbilirubinaemia in newborn infants is a safe and efficient form of therapy. The short-term side effects are not serious and seem to be well controlled. There are few long-term follow-up studies of phototherapy-treated infants. Therefore one cannot completely exclude the possibility that side effects can be found in future studies. With this background we undertook the present study of possible genotoxic effects of phototherapy. Human cells of the established glioblastoma cell line TMG-1 were used. The cells were exposed to visible light in the presence of different concentrations of bilirubin or in the absence of bilirubin. DNA was unwound in alkaline solution and the induction of strand breaks was assayed by a method taking advantage of the fluorescence from the dye Hoechst 33258. Blue light induced single-strand breaks in the DNA of cells in culture in the absence of bilirubin. During irradiation of bilirubin solutions with blue and green phototherapy light, long-lived toxic photoproducts were formed under in vitro conditions. At high and clinically relevant bilirubin concentrations, the effects of blue and green light were relatively similar. At low concentrations, there was a smaller effect of green light as expected from the absorption spectrum of bilirubin. It remains to be seen whether the genotoxic effect observed in the present studies can occur in vivo.

The Pattern of Bilirubin Response to Phototherapy for Neonatal Hyperbilirubinaemia

The pattern of bilirubin response to phototherapy was studied using lamps with an emission spectrum closely similar to the bilirubin absorption spectrum. A dose-response relationship was demonstrated, with increased intensity of phototherapy resulting in greater response; however, the rate of bilirubin decline progressively decreased with increasing radiance till a 'saturation' point was reached, beyond which no further response occurred with further increase in radiance, suggesting a curvilinear relationship of the nature of an asymptotic regression. At the 'saturation' point, a 24-h decline of about 50% was achieved. With extended periods of phototherapy, a gradually decreasing response to phototherapy with declining bilirubin levels was observed, both with maximal or moderate intensity phototherapy; an exponential regression was suggested. At about 5 mg/dl little further decline was observed with continued phototherapy. The rate of the 24-h decline evaluated at 6-h intervals was observed to be proportional to the bilirubin level at the start of the 24-h period.

Binding of Bilirubin with Lipid: A POSSIBLE MECHANISM OF ITS TOXIC REACTIONS IN MITOCHONDRIA

Binding of bilirubin with mitochondria, mitochondrial membranes, various cells, and cellular fragments resulted in a hypochromicity with a red shift of the absorption spectrum of bilirubin. It was found that the mitochondrial lipids rather than the proteins were involved in the binding. Isolated mitochondrial lipid and lipids from various other sources caused similar spectral changes of the bilirubin absorbance. Exogenous lipid could prevent the toxic effect of bilirubin on well defined mitochondrial reactions as did serum albumin. Washing of bilirubin-treated mitochondria with albumin restored their normal function to a considerable extent. These findings suggest that the binding of bilirubin with lipid alters the characteristics of mitochondrial membranes so that membrane-linked functions are impaired. In view of the lipophilic nature of bilirubin, this explanation might be considered as a mechanism of toxicity of bilirubin for cells in general.

On Infrared Absorption Spectra of Bilirubin and Calcium Bilirubinate

This paper deals with the infrared absorption spectra of bilirubin and calcium bilirubinate in order to provide a better understanding in the analysis of gallstones by means of infrared spectroscopy. The infrared spectra of these two authentic compounds, together with powdered pigmented calcium stones and their fractions, have been measured for the purpose of establishing the position and assignment of the characteristic absorption bands. As a result, several erroneous interpretations by previous authors of the spectrum of bilirubin, especially as regards absorptions of carboxyl groups, have been noted. Moreover, some absorption bands which were previously regarded to be characteristic of calcium bilirubinate have been attributed to ethanol-extractable ingredients of the pigmented calcium stone; calcium bilirubinate, both authentic material and a specimen obtained from the residue from ethanol extraction of the pigmented calcium stone, showed a spectrum suggesting bilirubin to be present in the form of its carboxylate.