Judul: Synthesis of Nanoparticles Chitosan - Ethanol Spirulina sp. Extract as Antibacterial Preparations
Abstrak: Spirulina dengan komponen bioaktif dan aktivitas antibakteri dapat dimanfaatkan sebagai sediaan antibakteri pada produk kosmeseutikal. Produk kosmeseutikal yang digunakan untuk pengobatan jerawat umumnya berupa skin care yang mengandung antibiotik dalam sediaan cream/emulsi dengan jumlah produk antijerawat yang sudah memiliki izin BPOM sekitar 636 produk. Produk emulsi memiliki kekurangan dalam proses penetrasi kedalam kulit dan kandungan antibiotik dapat menyebabkan resistensi jika digunakan secara terus menerus. Penelitian ini menjadikan kekurangan tersebut untuk berinovasi dalam membuat sediaan antibakteri berbasis nanopartikel dengan menggunakan kitosan dan ekstrak Spirulina sp. Perlakuan yang diberikan yaitu perbedaan konsentrasi ekstrak yang terdiri atas konsentrasi stok ekstrak 3,25 mg/mL (F1), 7,5 mg/mL (F2), dan 15 mg/mL (F3). Metode gelasi ionik digunakan untuk membuat nanopartikel (gugus negatif: kitosan, gugus positif: sodium tripolifosfat). Rendemen pada maserasi Spirulina dengan etanol 96% sebesar 13,87 ± 1,67% dengan komponen aktif berupa saponin, tanin, steroid dan fenol yang berpotensi sebagai antibakteri. Formula 1 (F1) sebagai perlakuan terbaik memiliki ukuran partikel 428,125 nm, indeks polidispersitas (PdI) 0,513 dan count rate 304,425x103 kcps. Aktivitas antibakteri pada ekstrak Spirulina (0,42 µg/disk) dan nanopartikel F1 masuk golongan zona hambat sedang (5 – 10 mm) pada bakteri uji bakteri Staphylococcus aureus dan Pseudomonas aeruginosa. Kontrol positif (klindamisin 0,4 µg/disk) masuk dalam golongan zona hambat tinggi (>10 mm) pada kedua bakteri uji. Nanopartikel kitosan – ekstrak etanol Spirulina sp. memiliki potensi sebagai sediaan antibakteri produk kosmeseutika dan teknologi nanoenkapsulasi terbukti dapat meningkatkan aktifitas antibakteri pada ekstrak Spirulina., Spirulina with bioactive components and antibacterial activity can be used as an antibacterial preparation in cosmeceutical products. Cosmeceutical products used for acne treatment are generally in the form of skin care containing antibiotics in cream/emulsion preparations with the number of anti-acne products that already have BPOM approval of about 636 products. Emulsion products have shortcomings in the process of penetration into the skin and the content of antibiotics can cause resistance if used continuously. This research makes this shortcoming for particles in making nano-based antibacterial preparations using chitosan and Spirulina sp. The treatments given were differences in extract concentrations consisting of extract concentrations of 3,25 mg/mL (F1), 7,5 mg/mL (F2), and 15 mg/mL (F3). Ionic gelation method used to make nanoparticles (negative group: chitosan, positive group: sodium tripolyphosphate). The yield on maceration of Spirulina with 96% ethanol was 13,87 ± 1,67 with active components in the form of saponins, tannins, steroids and phenols potentially as antibacterial. Formula 1 (F1) as the best treatment had a particle size of 428,125 nm, a polydispersity index (PdI) of 0,513 and a count rate of 304,425x103 kcps. Antibacterial activity of Spirulina extract (0,42 g/disk) and F1 nanoparticles were classified as moderate inhibition zone (5 – 10 mm) on Staphylococcus aureus and Pseudomonas aeruginosa as the test bacteria. The positive control (clindamycin 0,4 g/disk) was included in the high inhibition zone group (>10 mm) in both test bacteria. Chitosan nanoparticles – ethanol extract of Spirulina sp. potentially as a cosmeceutical antibacterial product preparation and nanoencapsulation technology has been shown to increase the antibacterial activity of Spirulina extract.
Keyword: Spirulina, kompenen bioaktif, antibakteri, kitosan, nanopartikel

Judul: Nanoencapsulation of Phycocyanin from Spirulina platensis Using Chitosan with Different Polymer Lengths for Transdermal Delivery Applications
Abstrak: Fikosianin dari Spirulina platensis memiliki sifat bioaktif seperti antioksidan dan antikanker, tetapi kemurniannya sulit dicapai dengan metode konvensional. Sistem aqueous two phase dengan Natural Deep Eutectic Solvent (NaDES) menawarkan pemurnian lebih efisien. Tantangan stabilitas dan berat molekul tinggi diatasi dengan nanoenkapsulasi menggunakan kitosan. Penelitian ini menentukan metode pemurnian terbaik dan formulasi nanopartikel fikosianin-kitosan, serta mengevaluasi pengantaran transdermal dan aktivitas bioaktifnya. Hasil menunjukkan formula nanopartikel terbaik adalah NPC-LC dengan ukuran partikel 275,43 nm. Aktivitas antioksidan meningkat, dan nano-fikosianin tidak toksik terhadap sel normal, tetapi efektif melawan sel kanker melanoma., Phycocyanin from Spirulina platensis possesses bioactive properties such as antioxidant and anticancer activities, but its purity is challenging to achieve using conventional methods. The aqueous two-phase system with natural deep eutectic solvents (NaDES) offers more efficient purification. The challenges of stability and high molecular weight are addressed through nanoencapsulation using chitosan. This study determines the best purification method and the formulation of phycocyanin-chitosan nanoparticles, as well as evaluates their transdermal delivery and bioactive activity. Results showed that the best nanoparticle formulation is NPC-LC with a particle size of 275.43 nm. Antioxidant activity increased, and nano-phycocyanin is non-toxic to normal cells but effective against melanoma cancer cells.
Keyword: antioxidant, aqueous-two-phase, microalgae, NaDES, purification

Judul: Analysis of Unequal Income Distribution with Cobb-Douglas Production Function
Abstrak: This paper studies the economic growth model by Moav (2002). Moav model shows the existence of unequal income distribution between low-income with high-income community. That kind of unequal income distribution is caused by uneven distribution of income. On this Moav model, there is one area called the threshold. Threshold becomes a benchmark to determining whether a society is categorized into low- or high- income community. The production function used in this paper is the Cobb-Douglas function. The dynamics of this model is described as difference equation of low-income, threshold, and high-income community. Simulation study on the model is carried out using Maple 13 and Mathematica 7.0 software. Overall, from the observed case, high-income community will reach a stable condition earlier, followed by the threshold, and then the low-income community.
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