**2. Recent space-age advancements of LED and its phototoxic-cumbactericidal effect of blue LED irradiation**

In the past few years, incredible developments have been made in LED technologies. In the ambience of lighting industry, LED technology forms one of the energetic forces besides new lighting notions and applications. The accelerated change produce in product design yields the respective powerful light sources. One of the more fundamental advancements, which has promise in the LED arena, is from the nanotechnology referred to as "quantum dots." Being make a breakthrough in efficiency, the respective ultra-small crystals would possess unique properties that could be tuned to emit light covering the visibility spectrum. This is highly important because when these particles are in a confined state, they would have the potential to provide diverse options for color for a while producing an improved white. The uniformity, quality, and tonal color of an LED source desperately add to its allure in usage in commercial production applications. Color stability in fact is one of the more accelerating developments seen recently. Using inorganic packaging associated with flip-chip mounting, the features of the phosphor layer are matched to each chip's individual characteristics. As a result, firms could now suggest white LEDs that have a highly precise prefixed color temperature without the discarding necessary to account for natural changes in color. Another significant advancement in LED technologies has to be done with the material which is in the usage in their production and the resulting efficacy of that production. With one emerging technology, LED lighting could be made with a mixture of organic and inorganic materials. The cumulative effect of this technology is somewhat than typical four or five layers of material would be necessary in producing the product; this new material necessitates just one layer. This vividly lowers the cost of production and produces the manufacturing process relatively easier. This is yielding lower cost for LED light sources while performance continues to enhance. This emerges the new technology to more and more potential applications all over the time [56].

A recent study of the bactericidal and phototoxic effect of blue LED irradiation revealed that LED irradiation persuades apoptosis by triggering a mitochondria-mediated pathway and reducing the preliminary growth rate of melanoma cells [57]. Oh et al. observed that irradiation with blue LEDs abridged cell feasibility and thus persuaded apoptotic cell death with the mouse A20 and human RAMOS B-cell lymphoma cells [58]. As a potential risk of high energy LED lamps, lighting at night may disturb the body's biological clock, the circadian rhythm. According to the Harvard Health Letter "Blue light has a dark side," the blue wavelengths seem to be the most harmful at night and comprise a large portion in the emission of CFLs and LED lamps [59, 60].
