Self-assembled biodegradable 2D platelet particles and their journey inside the cells

In this Thesis, a class of well-defined, bio- degradable and compatible 2D platelet particles for biomedical application is prepared. A diblock glycopolymer system is used, consisting glycopolymers and semi-crystalline poly(ε-caprolactone). The first section investigates the self-assembly behavior of these polymers in selective solvents. The study is then extended to prepare well-defined 2D platelet particles with different sizes by using living crystallization-driven self-assembly (CDSA). Platelet particles are also prepared using conjugated polymers bearing anti-cancer drug doxorubicin, or Cyanine5 dye. This system offers potential opportunities for the particles to be used as drug delivery vectors. A derivatized system includes the preparation of 2D particles with readily available amine handles on the surface. The amine groups can be used for functionalization or attachment with ligands via post-modification approach, enabling facile incorporation of fluorophores and biomolecules. The last chapter of this Thesis reveals the cellular uptake mechanism of the particles and their intracellular trafficking using in vitro 2D cell culture assay. These studies reveal a prevalent uptake of the particles regardless of their size by macrophages (RAW 264.7) compared to mouse embryonic fibroblasts (MEFs) and hepatocellular carcinoma (HepG2) cell lines. Using elaborate microscopy techniques, the journey of the particles is probed from the point of entry (endocytosis) up to particle degradation in the lysosomes. Upon entry, the particles undergo trafficking from early endosomes, late endosomes, and lysosomes. Quantification of the lysosomal degradation of the platelets reveals that approximately 80% of the particles were already degraded within 48 h. Overall, this Thesis presents a robust strategy to prepare biodegradable, homogenous 2D platelet particles and highlights their potential role in biomedical application. This work is relevant for multidisciplinary researchers working in the fields of polymer self-assembly, supramolecular chemistry, and those focusing on the nano-bio interaction of polymeric particles for drug delivery. Notably, the results obtained from our biological studies underscore the opportunities for these particles to be used specifically to target the immune cells, lymphatic system, or lysosomal storage diseases

Analisis perbandingan pajak terutang dengan menggunakan norma penghitungan dan pembukuan berdasarkan perubahan undang-undang pajak penghasilan

Penelitian ini memiliki tujuan, untuk mengetahui manakah yang lebih menguntungkan bagi wajib pajak orang pribadi yang menggunakan norma penghitungan dan yang menggunakan pembukuan berdasarkan tarif pasal 17 UU PPh sebelum dan sesudah tahun 2000. Penelitian ini menggunakan 2 contoh bentuk usaha yang masih berdiri pada tahun 1999 hingga tahun 2002. Yang pertama sebuah perusahaan perseorangan yang pada saat berdiri menggunakan norma penghitungan lalu mengubah bentuk usahanya menjadi sebuah CV. Yang kedua merupakan sebuah perusahaan perseorangan yang pada saat berdiri hingga sekarang menggunakan pembukuan. Penelitian ini membuktikan bahwa dengan adanya perubahan UU PPh menyebabkan pajak terutang dari perusahaan perseorangan yang menggunakan pembukuan lebih menguntungkan daripada menggunakan norma penghitungan

Covalent Tethering of Temperature Responsive pNIPAm onto TEMPO-Oxidized Cellulose Nanofibrils via Three-Component Passerini Reaction

A critical challenge in the application of functional cellulose fibrils is to perform efficient surface modification without disrupting the original properties. Three-component Passerini reaction (Passerini 3-CR) is regarded as an effective functionalization approach which can be carried out under mild and fast reaction condition. In this study, we investigated the application of Passerini 3-CR for the synthesis of thermoresponsive cellulose fibrils by covalently tethering poly­(<i>N</i>-isopropylacrylamide) in aqueous condition at ambient temperature. The three components, a TEMPO-oxidized cellulose nanofiber bearing carboxylic acid moieties (TOCN-COOH), a functionalized polymer with aldehyde group (pNIPAm-COH) and a cyclohexyl isocyanide, were reacted in one pot resulting in 36% of grafting efficiency within 30 min. The chemical coupling was evidenced by improved aqueous dispersibility, which was further confirmed by FT-IR, TGA, UV–vis, and turbidity study. It was observed that the grafting efficiency is strongly dependent on the chain length of the polymer. Furthermore, AFM and X-ray diffraction measurements affirmed the suitability of the proposed method for chemical modification of cellulose nanofibers without significantly compromising the original morphology and structural integrity

Inhibitive S. aureus Infection to HUVECs Induced by Trehalose and Glucose-functionalized Gold Nanoparticles

Microbial adhesion to host cells represents the initial step in the infection process. Several methods have been explored to inhibit microbial adhesion including the use of glycopolymers based on mannose, galactose, sialic acid and glucose. These sugar receptors are however abundant in the body and they are not unique to bacteria. Trehalose in con-trast is a unique disaccharide that wildly expressed by mi-crobes. The role of trehalose in bacteria has widely been in-vestigated but this carbohydrate has not yet been explored as anti-adhesive. Herein, gold nanoparticles (AuNPs) coated with trehalose-based polymers have been prepared and compared to AuNPs coated with glucose-functionalized were developed to inhibit. Acting as anti-adhesive, trehalose-functionalized nanoparticles particularly decreased the infec-tion of HUVEC cells by S. aureus, while outperforming the control nanoparticles. Microscopy revealed that trehalose coated nanoparticle bind strongly to S. aureus compared to the controls. As a conclusion, nanoparticles based on treha-lose could be suitable to inhibit S. aureus infection