Blue Light and Ultraviolet Radiation Exposure from Infant Phototherapy Equipment

Photomedicine based on heme-derived compounds

Photoimaging and phototherapy have become major platforms for the diagnosis and treatment of various health complications. These applications require a photosensitizer (PS) that is capable of absorbing light from a source and converting it into other energy forms for detection and therapy. While synthetic inorganic materials such as quantum dots and gold nanorods have been widely explored for their medical diagnosis and photodynamic (PDT) and photothermal (PTT) therapy capabilities, translation of these technologies has lagged, primarily owing to potential cytotoxicity and immunogenicity issues. Of the various photoreactive molecules, the naturally occurring endogenous compound heme, a constituent of red blood cells, and its derivatives, porphyrin, biliverdin and bilirubin, have shown immense potential as noteworthy candidates for clinically translatable photoreactive agents, as evidenced by previous reports. While porphyrin-based photomedicines have attracted significant attention and are well documented, research on photomedicines based on two other heme-derived compounds, biliverdin and bilirubin, has been relatively lacking. In this review, we summarize the unique photoproperties of heme-derived compounds and outline recent efforts to use them in biomedical imaging and phototherapy applications.

A deoxygenation-switch-based red-emitting fluorogenic light-up probe for the detection of highly toxic free bilirubin in human blood serum

Reaction-based chemical switches are attracting great interest due to their high selectivity, and their use has become a powerful technique for developing fluorogenic probes. Herein, a benzorhodol-derivative-attached N-oxide probe (DEBNox) has been designed as a new fluorogenic probe for the detection of the biologically toxic species bilirubin based on a deoxygenation switching mechanism. Upon reaction with added Fe³⁺, bilirubin produces Fe²⁺ ions in situ, which in turn promote a deoxygenation reaction with DEBNox to generate the corresponding high-red-fluorescence (λ_em: ∼623 nm) benzorhodol derivative (DEB). This type of Fe³⁺-mediated response helps the probe to act as a qualified turn on selective fluorescence sensor for bilirubin with a detection range as low as 33 nM. Moreover, the probe was successfully employed to detect free bilirubin in human blood serum specimens with acceptable accuracy and reliability. This DEBNox-based light-up strategy also facilitates the construction of reliable and highly sensitive assays based on a paper-based strategy, similar to pH-indicator paper, as is demonstrated here via bilirubin detection in real serum samples. These findings could be useful for developing powerful diagnostic tools for the detection of free bilirubin in the near further.

Blue light exposure in the workplace: a case study of nail salons

Fluorescent or LED nail lamps are used in manicure and pedicure salons to cure nail coatings. These are UV sources, but with significant blue light emissions. Most of the literature emphasizes skin damage and cancer risk from UV exposure rather than blue light-induced damage to visual photoreceptors. Nail technicians using the lamps routinely may have potentially greater exposure than customers. However, there are no data on blue light radiance levels combined with time activity patterns for exposure assessment. This research aimed to determine exposures through simulation experiments, informed by observational studies in seven nail salons. Typical and worst-case time activity patterns were established, and spectral radiance doses determined in the occupational visual field for two LED nail curing lamps. The results showed the effective spectral radiance dose were below the current guideline promulgated by the International Commission on Non-Ionising Radiation Protection. Interestingly, radiances at the corners of one LED nail curing lamp was higher than at the center, which shows the amount of exposure can differ depending on the viewing angle. This research is the first to determine spectral radiance doses. A covered design is highly recommended for blocking the emission of blue light from a nail lamp.

An Extensive Collection of Evaluation Indicators to Assess Occupants’ Health and Comfort in Indoor Environment

Today, the effects of the indoor environment on occupants’ health and comfort represent a very important topic and requires a holistic approach in which the four main environmental factors (thermal comfort, air quality, acoustics, and lighting) should be simultaneously assessed. The present paper shows the results of a literature survey that aimed to collect the indicators for the evaluation of occupants’ health and comfort in indoor environmental quality evaluations. A broad number of papers that propose the indicators of a specific environmental factor is available in the scientific literature, but a review that collects the indicators of all four factors is lacking. In this review paper, the difference between indicators for the evaluation of risk for human health and for comfort evaluation is clarified. For each environmental factor, the risk for human health indicators are proposed with the relative threshold values, and the human comfort indicators are grouped into categories according to the number of parameters included, or the specific field of application for which they are proposed. Furthermore, the differences between human health and comfort indicators are highlighted.

Non-Ionizing Radiation in Swedish Health Care-Exposure and Safety Aspects

The main aim of the study was to identify and describe methods using non-ionizing radiation (NIR) such as electromagnetic fields (EMF) and optical radiation in Swedish health care. By examining anticipated exposure levels and by identifying possible health hazards we also aimed to recognize knowledge gaps in the field. NIR is mainly used in health care for diagnosis and therapy. Three applications were identified where acute effects cannot be ruled out: magnetic resonance imaging (MRI), transcranial magnetic stimulation (TMS) and electrosurgery. When using optical radiation, such as class 3 and 4 lasers for therapy or surgical procedures and ultra-violet light for therapy, acute effects such as unintentional burns, photo reactions, erythema and effects on the eyes need to be avoided. There is a need for more knowledge regarding long-term effects of MRI as well as on the combination of different NIR exposures. Based on literature and after consulting staff we conclude that the health care professionals' knowledge about the risks and safety measures should be improved and that there is a need for clear, evidence-based information from reliable sources, and it should be obvious to the user which source to address.

Safety of neonatal phototherapy lamp exposure

A routine review of light exposure within a neonatal intensive care unit is described following the introduction of a new model of neonatal phototherapy lamp. Spectral measurements were undertaken using a Bentham Dmc150 spectroradiometer system. Safety assessments were undertaken based on likely exposure of parents at the cot side, neonates in adjacent cots and the effectiveness of eye protection for neonates with direct phototherapy. An aphakic eye response was used for assessment of neonatal risk and the blue-light response for estimation of adult exposure using current ICNIRP guidelines. Such estimations indicated exposure levels of parents at the cot side and neonates in adjacent cots were within current established safe limits. The level of light blocking provided by the available neonatal eye protection was estimated to be entirely adequate and presented no hazard to the infant when correctly positioned over the neonate. It is likely, however, that an increased safety factor is potentially present for the neonate due to the fact that the neonate's eyes will typically be shut for over 50% of the time. It is identified, however, that the aphakic response is essentially associated with mature adult retinal cells, and that the maturing cells of the neonate may exhibit additional light sensitivity, especially in the case of premature infants. Changes in neonatal physiology associated with neonatal phototherapy are discussed, which may influence mechanisms of light-induced retinal damage.