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Pembentukan kornea gantian menggunakan sel stem mesenkima dari sum-sum tulang melalui teknologi kejuruteraan tisu

2026-06-08T12:16:39Z

Title: Pembentukan kornea gantian menggunakan sel stem mesenkima dari sum-sum tulang melalui teknologi kejuruteraan tisu Authors: Rohaina Che Man (P50282) Abstract: Lapisan epitelium kornea dikekalkan oleh sel stem limbal. Kehilangan sel stem limbal boleh menyebabkan kebutaan di mana epitelium limbal gagal berfungsi secara normal dan digantikan dengan epitelium konjunktiva dan salur darah. Sum-sum tulang telah dikenalpasti sebagai sumber sel progenitor untuk sel epitelium dan endotelium. Objektif kajian ini adalah untuk membentuk kornea gantian menggunakan sel stem mesenkima sum-sum tulang manusia (BMSCs) melalui teknologi kejuruteraan tisu seterusnya merawat kecacatan kornea pada model tikus atimik. Bagi pembentukan kornea gantian, BMSCs pada subkultur pertama telah dituai dan disemai di atas membran amniotik (AM) di dalam sistem kultur bersama "transwell" dengan kehadiran sel fibroblas (NIH3T3) yang tidak aktif sebagai sel bawahan. Pengaruhan dengan menggunakan alkali telah dilakukan ke atas tikus atimik untuk mengurangkan populasi sel stem limbal. Kornea gantian kemudiannya diimplan pada mata tikus atimik yang cedera selama 8 minggu. Ini diikuti dengan analisis lampu slit dan analisis Optical Coherence Tomography (OCT) secara bersiri. Analisis kuantitatif ekspresi gen menunjukkan peningkatan gen ẞ-integrin (2.75×10 4.85×102; p<0.05), C/EBP8 (2.63×1036.77x10; p<0.05), ABCG2 (2.32×105 ± 4.74×10; p>0.05) dan p63 (9.57×103.53×107; p<0.05) dalam BMSCs yang diaruh jika dibandingkan dengan BMSCs yang tidak diaruh. Manakala tiada pengekspresan gen CK3 berlaku pada kedua-dua kumpulan. Analisis immunositokimia menunjukkan adanya pewarnaan positif untuk CK3 (54.07 1.33; p<0.05) dan p63 (70.10 1.84; p<0.05) dalam BMSCs yang diaruh tetapi sebaliknya tiada pengekspresan pada BMSCs yang tidak diaruh. Kumpulan rawatan yang menggunakan kornea gantian menunjukkan bahawa penilaian lampu slit menunjukkan penjanaan semula kornea yang baik dari sudut kejelasan kornea dan pengurangan pembentukan baru salur darah jika dibandingkan dengan kumpulan kawalan yang lain. Kumpulan rawatan dengan sel mencapai tahap ketebalan kornea paling tinggi jika dibandingkan dengan kumpulan lain seperti yang ditunjukkan oleh analisis histologi dan OCT (BMSCs: 276.50 ± 4.77; AM: 129.11 ± 5.04; Kawalan: 244.50 5.63). Rawatan dengan BMSCs yang diaruh telah mencapai 4 hingga 5 lapisan epitelium yang teratur dan lapisan stromal yang padat menyerupai kornea normal. Analisis immunohistokimia menunjukkan kumpulan rawatan BMSCs dengan kombinasi AM dan kumpulan rawatan dengan AM sahaja menunjukkan pengekspresan protein CK3 dan p63 semasa proses regenerasi kornea yang baru. Sebaliknya, di dalam kumpulan kawalan, tiada pengekspresan protein yang ditunjukkan. Kesimpulannya, kajian ini menunjukkan bahawa sel BMSCs yang telah diaruh dan disemai ke atas AM boleh digunakan sebagai kornea gantian untuk merawat masalah kekurangan sel stem limbal akibat kecederaan alkali.

Effect of dermal fibroblasts conditioned medium (DFCM) on IN VITRO skin re- epithelialization

2026-06-08T12:16:29Z

Title: Effect of dermal fibroblasts conditioned medium (DFCM) on IN VITRO skin re- epithelialization Authors: Nurul' Izzah Haji Abdul Ghani (P72936) Abstract: A key event in wound healing is re-epithelialization, which is accomplished by the proliferation, migration, and differentiation of epidermal keratinocytes. These processes are mainly regulated via paracrine signaling of cytokines, chemokines and growth factors secreted by dermal fibroblasts. Impaired epithelialization, which is prevalent in chronic wounds and aging skin, is caused by lack of these essential factors. In vitro cell culture and protein extraction techniques enables collection of fibroblasts secreted factors from the waste medium as dermal fibroblast conditioned medium (DFCM), which could facilitate re-epithelialization during wound healing. The aim of the current study was to elucidate the effect of DFCM on in vitro re- epithelialization process i.e. keratinocyte attachment, proliferation, migration, and differentiation. Skin samples were collected from consented donors to isolate fibroblasts and keratinocytes. DFCM was prepared by culturing confluent fibroblasts with serum-free keratinocyte-specific (DFCM-KM) and fibroblast-specific (DFCM- FM) medium. Keratinocytes supplemented with DFCM were observed under time- lapse imaging to evaluate attachment, proliferation, and migration. The scratch assay was performed to assess keratinocytes rate of healing. DFCM collected with 3-day incubation of confluent fibroblasts (DFCM-KM-3 and DFCM-FM-3) were resulted in enhancement of keratinocyte re-epithelialization process compared to 1-day and 2-day incubation. It was also found that DFCM-KM-3 significantly enhanced keratinocyte attachment (77.66×10215.15×102 cells/cm2) compare to control (64.36×102+10.31×102 cells/cm3) and DFCM-FM-3 (50.58×10219.83×10 cells/cm2) (p<0.05). While, DFCM-FM-3 significantly increased keratinocyte wound healing (155.4×10 +5.24×102 um2/h) compare to control (115.5×10243.25×102um3/h) and DFCM-KM-3 (120.1x10 +5.24×102um2/h) (p<0.05). Moreover, supplementation of DFCM-FM-3 resulted in the enlargement of keratinocyte area and demonstrated collective migration during healing, which was distinctly different from keratinocytes supplemented with DFCM-KM-3 and on control condition. Further analysis confirms that the presence of high calcium in DFCM-FM-3 facilitated the changes. Also, to understand the effect of DFCM on re-epithelialization of aging skin, DFCM was supplemented to keratinocytes from 3 different age groups (≥18-35 years, 36-54 years and ≥55 years). It was found that irrespective of donor age, DFCM-KM-3 enhances keratinocyte attachment while DFCM-FM-3 enhances keratinocyte healing rate, indicating the potential application of DFCM for impaired re-epithelialization.

Developing woven jute-matrix composite for radiation effects and shielding efficacy evaluation

2026-06-08T13:04:03Z

Title: Developing woven jute-matrix composite for radiation effects and shielding efficacy evaluation Authors: Mohammad Zahirul Islam Mollah (P108969) Abstract: Concerned about environmental issues, non-biodegradable synthetic, and chemically modified synthetic polymeric materials produce primary and secondary microplastics that affect the ecosystem. The traditional lead-based shielding material has detrimental effects on humans and the environment. Composite products comprising naturally occurring polymers, deployed into matrixes are splendid creations of modern science that ultimately lessen the negative environmental consequences of synthetic polymers. Natural fibers have been utilized in different sectors due to their biocompatibility, biodegradability, and availability. The woven jute and matrix (polypropylene, polyester, and epoxy resin) have been selected to fabricate reinforcing semi-degradable materials using hand layup stacking sequence techniques. The radiation processing method is applied to improve the physico-mechanical properties of woven jute-matrix composites. The mechanical, thermal, topographical, and chemical properties have been examined using UTM (universal testing machine), DSC-TGA (differential scanning calorimetry-thermogravimetric analysis), SEM-EDS (scanning electron microscopic-energy-dispersive spectroscopy), and (Fourier transform infrared spectroscopy) FTIR for treated and untreated samples of woven jute composites. The impregnated woven jute-matrix composites like “jute-polypropylene (jute-PP)”, “jute-polyester resin (jute-PR)” and “jute-epoxy resin (jute-EPR)” were developed significantly. Firstly, the mechanical properties of 3-layer sequence composites achieved are superior to one- and 2-layer sequence composites. In evaluated jute-matrix composites: initial tensile strength (29 MPa), tensile modulus (1.4 GPa), bending modulus (1.88 GPa), and impact strength (5.88 kJ/m2) were higher in a one-layer jute-polyester resin composite (S4), and Eb% (4.4) was higher in the one-layer jute-polypropylene (S1) composite. Secondly, the 5 kGy doses showed the effective enhancement of mechanical properties. The tensile strength increase (45.37 %) was higher in S7 (one-layer jute-epoxy resin composite) than in S1 (one-layer jute-PP), and S4 (one-layer jute-EPR). The bending strength of 22.87 % increase (43 MPa) was achieved in S1 which is superior to S4 and S7. The tensile modulus increased (40 %) in S1 is superior to S4 (27.35 %) and S7 (10.38 %). The bending modulus was increased tremendously in S1 due to the thermoplastic nature of PP, while S7 is superior to S4 due to the thermosetting nature, same behaved at elongation at break (Eb%) which is the highest Eb % in S1. Except for S1, all the Eb % performed antagonistic effects to impact strength due to radiation, while impact strength (15.64 % kJ/m2) increased in S4 is superior to S7. The water uptake decreased in irradiated samples, thermal properties showed remarkable changes indicating glass transition, crystallization, and degradation of jute-matrix composites. The FTIR and SEM-EDS represented that jute and matrix created uniform bonds with jute-matrix good adhesion which helped to enhance mechanical properties. Thirdly, the shielding efficacy of jute-PP, jute-PR, and jute-EPR composites was performed in the thumb rule indicating the highest mass attenuation coefficient (MAC) in S1. At the same time, S4 showed the lowest linear attenuation coefficient (LAC), a good half-value layer (HVL), a tenth-value layer (TVL), and a sixth-value layer (SVL). Consequently, S4 showed the lowest mean free path (MFP) and highest radiation protection efficiency. Thus, woven jute-matrix composites can be applied to reduce dependency on lead-based shielding materials. The findings of woven jute matrix composites can play a vital role in developing polymeric materials for engineering applications in environmental remediation.

Meta resonator based miniaturized planar microwave sensors for material permittivity characterization

2026-06-08T13:03:59Z

Title: Meta resonator based miniaturized planar microwave sensors for material permittivity characterization Authors: Abu Hanif (P121291) Abstract: Material permittivity is essential in applications like material characterization, environmental monitoring, and quality control, as it determines the ability to store electrical energy and affects electromagnetic (EM) wave propagation. Low permittivity materials are essential in integrated circuit design to reduce parasitic capacitance and propagation delay, thus ensuring electronic system performance. Measuring material permittivity precisely is challenging due to the limited sensitivity of measurement equipment, complex calibration processes, environmental factors, frequency dependence issues with material interfaces, sample size and uniformity. These challenges impact material characterization, device design, and performance. Techniques like the resonance method, resonant cavity method, free space method, and microstrip line method are being developed to measure permittivity, with the resonance based method being popular for its compact size, low cost, easy fabrication, and high sensitivity. Metamaterial technology is promising for enhancing the sensitivity of resonance-based sensors in the microwave frequency range. This research focuses on designing two microwave sensors for permittivity measurement with enhanced sensitivity and a compact size of 25 mm × 20 mm × 0.79 mm. The first sensor, a labyrinth-shaped circular split ring resonator (LC-SRR), is designed to operate at 2.57 GHz. This sensor achieves a high sensitivity of 10.50% for permittivity variation. The LC-SRR sensor was calibrated for a relative permittivity range of 2.2 to 4.3. The second sensor is a dual-notch maze-shaped complementary split ring resonator (MCSRR) that operates at 2.88 GHz and at 4.05 GHz. The MCSRR sensor shows sensitivities of 10.48% for the first notch and 17.36% for the second notch and calibrated for a relative permittivity range of 2.2 to 11.2, respectively. Both sensors are validated by fabricating and measuring prototypes. An inverse regression model is utilized to predict the permittivity of the material under test (MUT) directly from the sensor's resonant frequency. The contribution of this thesis is to design a split ring resonator (SRR) and a complementary split ring resonator (CSRR) that adopt a unique and compact structure, featuring high electromagnetic (EM) field intensity. This design contributes to a more precise sensing mechanism in the microwave frequency range.