益生菌（Probiotics），源於希臘語「for life」（對生命有益），根據世界衛生組織WHO的定義,大量菌的存在對宿主（例如動植物或人類）有正面效益即為益生菌，例如最為人所熟知的腸胃道的益生菌-乳酸菌，除了健胃整腸助消化，先前研究更指出，腸胃道的益生菌會進行發酵反應，產生化學電能發電，此外，並產生短鏈脂肪酸，進而增進大腦運作如情緒或認知功能，稱為 gut-brain axis (GBA) 。此外，研究亦發現，人體上的皮膚細菌也像腸胃道菌一樣，也會進行發酵反應，產生短鏈脂肪酸，尤其是人體微生物總體中兩種主要細菌:丙酸桿菌（嗜酸性桿菌）和表皮葡萄球菌（表皮葡萄球菌）， 都可以利用甘油作為發酵的碳源，同時在細菌發酵的過程中產生電能，提升電壓，有鑑於此，本研究主要的目的為將微生物發電應用推廣至皮膚細菌上，檢驗表皮葡萄球菌存在是否對腦部的神經電訊號(腦電圖EEG)也有像腸胃道益生菌有gut-brain axis (GBA)一樣的影響，以及探討其定性定量的機制。 ;Probiotics (from Greek root : for life ), are defined as live microorganisms that, "when administered in adequate amounts, confer a health benefit on the host” by World Health Organization (WHO). Lactobacillus bulgaricus, for example, are the most well-known probiotic bacteria in the gastrointestinal tract for their help in digestion. Previous studies have proved that probiotics in the gastrointestinal tract can undergo fermentation and generate chemical electrical energy, resulting in the increase of electric voltage. In addition, they produce short-chain fatty acids, which in turn improve brain function such as mood or cognitive function, called gut-brain axis (GBA). Importantly, new evidence has also shown that skin bacteria, particularly Propionibacterium (or Cutibacterium ) acnes (P. acnes) and Staphylococcus epidermidis (S. epidermidis) in human skin microbiome, like gastrointestinal bacteria, can undergo fermentation reactions to produce short-chain fatty acids and elevate the chemical electrical energy. Therefore. This proposal aims to examine whether the S. epidermidis can act as probiotics to improve the cognition function reflecting in the modulation of brain waves measured with electroencepholography (EEG).
