SYNTHESIS AND STUDY OF PHB-ECTOINE MICROPARTICLES WITH RHAMNOLIPID AS ANTI IRRITATION, ANTI-UVB, AND ANTIBACTERIAL AGENTS

• Main Author: Tyara Simbara, Alma
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/82774
• Institution: Institut Teknologi Bandung

The skin is the body's outermost layer, serving as a barrier against external threats like viruses, bacteria, and radiation. It also contains various sensors that help regulate body temperature and synthesize vitamin D. As a vital organ, the skin's integrity is crucial for overall health, necessitating proper care and preservation. Currently, numerous studies focus on incorporating natural ingredients such as PHB (Poly-(R)-3-hydroxybutyrate), ectoine (2-methyl-1,4,5,6 tetrahydropyrimidine-4-carboxylate), and rhamnolipid in skincare products. PHB, a biopolymer produced by bacteria, protects the skin from UVB radiation. Ectoine provides hydration and prevents irritation, while rhamnolipid, a biosurfactant, acts as an antibacterial agent. These compounds are proven safe as they are non-toxic to skin cells. Given their benefits, this study aims to develop a formulation using PHB, ectoine, and rhamnolipid to serve as an anti-irritant, anti-UVB, and antibacterial agents. In this study, PHB and ectoine were covalently bound to create PHB-ectoine microparticles (PHB-ectoine MPs), and rhamnolipid was added to the formulation to disperse the PHB-ectoine MPs, resulting in microfluids. This approach ensures that the function of each compound is preserved and they do not interfere with each other in the formulation. PHB and ectoine were linked using the crosslinking agent EDC (1-ethyl-3-(3 dimethylaminopropyl) carbodiimide), which facilitates the formation of amide bonds between the carboxylate group on PHB and the amine group on ectoine. The success of this binding process is evident from the physicochemical characteristics of the prepared microparticles. FTIR analysis reveals that the spectrum of PHB ectoine MPs contains characteristic absorption peaks of both PHB and ectoine, such as the absorption at 1738 cm-1 indicating a carbonyl ester group of PHB and the absorption at 1290 cm-1 indicating an amine group of ectoine. Additionally, the absorption at 1663 cm-1 confirms the formation of an amide bond between PHB and ectoine. Morphological and compositional analysis using SEM-EDS and TEM showed that PHB-ectoine MPs have a spherical shape with two distinct layers, an inner layer and an outer one, with an elemental composition of 95.17% carbon, 4.41% oxygen, and 0.41% nitrogen by mass. The microparticles measure 1.28 ± 0.61 µm when dispersed in water and 0.53 ± 0.23 µm when dispersed in rhamnolipid, with a surface charge of -61.47 ± 0.64 mV at pH 7. The anti-irritation, anti-UVB, and antibacterial activities of PHB-ectoine MPs formulated with rhamnolipid demonstrate that these three compounds work synergistically without interfering with each other. Microparticles at a concentration of 1% (w/v) protected 96.77% of zein protein from denaturation by synthetic surfactants (SDS) and 96.55% from denaturation by biosurfactants (rhamnolipids). Anti-UVB tests showed that PHB-ectoine MPs had an SPF value of 5.64 ± 0.30, with 82.3% UVB protection. While, microfluidics containing rhamnolipid-PHB-ectoine MPs had an SPF value of 5.06 ± 0.24 and 80.2% UVB protection. Antibacterial tests indicated that PHB-ectoine MPs had no activity against Gram-negative Escherichia coli (E. coli) or Gram-positive Staphylococcus aureus (S. aureus). In contrast, rhamnolipids exhibited effective antibacterial activity against S. aureus, producing an inhibition zone of 356 ± 25 mm² at a concentration of 10 mg/mL. Adding PHB ectoine MPs at a concentration of 5 mg/mL to 10 mg/mL rhamnolipid increased the inhibition zone to 472 ± 114 mm². These findings suggest that multifunctional microparticles from PHB and ectoine were successfully synthesized using a simple method, with the formulation incorporating rhamnolipid showing great potential for development into skincare products such as moisturizers (anti-irritation), sunscreens (anti-UVB), and facial cleansers (antibacterial).