Preparation and Characterisation of Polystyrene Grafted Sago Starch

Styrene grafting onto sago starch was carried out by using eerie ammonium nitrate (CAN) as a redox initiator. The parameters affecting the grafting reaction were investigated and the optimum conditions obtained are as follows: temperature, 50°C; nitric acid concentration, 0.01 M; amount of styrene, 0.35 mol; amount of CAN, 16.8 x 10-4 mol and reaction period, 2h. Percentages of grafting and grafting efficiency under the optimum condition were 53.92% and 73.21%, respectively. Reactions in the presence of nitrogen gas resulted in higher percentages of grafting and grafting efficiency. FTIR spectra analysis of the grafted chain and polystyrene was identical indicating that styrene was successfully grafted onto sago starch. TGA thermograms, DSC curves and SEM photographs of sago starch-g poly(styrene) and the original polymers (sago starch and polystyrene) were different which suggested that styrene was grafted onto sago starch. The bio-degradability study using a-amylase showed that the rate of degradation of gelatinised sago starch was higher than that of sago starch-gpoly( styrene). The highest rate of degradation of sago starch-gpoly(styrene) was obtained at 50 ppm of a-amylase concentration. Viscosity measurements showed that the intrinsic viscosity and the average molecular weight (Mv) increased with the increase in the percentage of grafted polystyrene. The Mv of the various percentages of grafted polystyrene were in the order of 104. The results obtained from the swelling of sago starch-gpoly(styrene) in polar and non polar solvents showed that the percentage of swelling at equilibrium and the swelling rate coefficient decreased in the following order: DMSO > water > acetone > cyclohexanone = CHCh > toluene = CCl4. Diffusions of the solvents onto the polymers were found to be of a Fickian only for DMSO

Optimization of reaction conditions for preparing carboxymethyl cellulose from sago waste

Sago pulp (57% w/w) isolated from sago waste was converted to carboxymethyl cellulose (CMC) by etherification using sodium monochloroacetate and sodium hydroxide. The reaction was optimized against temperature, concentration and reaction time. The optimized product has a large degree of substitution (DS) of 0.821, which compared favorably to other forms of cellulose. Fourier Transform Infrared spectra (FTIR) were used to characterize the product and starting sago pulp. Digital photographs of sago waste and sago pulp showed the expected rough woody structure while that of the CMC generated from the pulp showed a smooth surface morphology

Absorption characterization of Ca2+, Na+, and K + on irradiation crosslinked carboxymethyl sago pulp hydrogel.

Hydrogel of carboxymethyl sago pulp (CMSP) of various degree of substitution (DS) was prepared by electron beam irradiation of various radiation doses. The CMSP hydrogels were subjected to swelling in different ionic strength solutions of KCl, NaCl, and CaCl2. The CMSP hydrogels, due to its polyelectrolyte nature, were found to be highly sensitive to ionic strength of the medium. All the CMSP hydrogels showed the absorption of K+ and Ca2+ increases with the increase in the concentrations of the respective cation solutions. The cation absorption also decreases with DS and % gel fraction (%GF) of the CMSP hydrogels. Subjecting the CMSP hydrogels in NaCl results in deswelling and releases Na+ to swelling medium where the Na+ release increases with the increase of DS and %GF. The sorption capacity depends on the extent of crosslinking and decreases with the increase in the extent of crosslinking

Application of metal nanoparticle–hydrogel composites in tissue regeneration

Challenges in organ transplantation such as high organ demand and biocompatibility issues have led scientists in the field of tissue engineering and regenerative medicine to work on the use of scaffolds as an alternative to transplantation. Among different types of scaffolds, polymeric hydrogel scaffolds have received considerable attention because of their biocompatibility and structural similarity to native tissues. However, hydrogel scaffolds have several limitations, such as weak mechanical property and a lack of bioactive property. On the other hand, noble metal particles, particularly gold (Au) and silver (Ag) nanoparticles (NPs), can be incorporated into the hydrogel matrix to form NP–hydrogel composite scaffolds with enhanced physical and biological properties. This review aims to highlight the potential of these hybrid materials in tissue engineering applications. Additionally, the main approaches that have been used for the synthesis of NP–hydrogel composites and the possible limitations and challenges associated with the application of these materials are discusse

Ekstremisme ganas dan semakan kehakiman dalam kes-kes berkaitan dengannya dari perspektif Undang-Undang Tahanan Pencegahan Malaysia

Resolusi 2178 (2014) dan Pelan Tindakan Mencegah Ekstremisme Ganas (Pelan Tindakan) pada peringkat Pertubuhan Bangsa-bangsa Bersatu (PBB) menyeru negara-negara anggota untuk membentuk satu pelan tindakan negara yang merangkumi langkah-langkah berkesan dalam mencegah ekstremisme ganas. Dari perspektif undang-undang, setiap negara dikehendaki untuk memastikan kedaulatan undang-undang dan hak asasi manusia tidak terjejas oleh lanjutan daripada penguatkuasaan undang-undang berkaitan. Semakan kehakiman dilihat sebagai salah satu perkara asas kepada pentadbiran yang baik dalam menjamin kedaulatan undang-undang. Secara lazimnya, undang-undang tahanan pencegahan menjadi pilihan utama badan eksekutif untuk menahan seseorang yang dipercayai ada hubung kait atau terlibat dalam perbuatan yang menjejaskan keselamatan negara. Undang-undang tersebut juga digunakan untuk mencegah ekstremis ganas yang berpotensi mengancam ketenteraman awam dan keselamatan negara. Lantaran itu, artikel ini bertujuan menganalisis sejauh manakah undang-undang tahanan pencegahan Malaysia sesuai dalam menangani ekstremisme ganas dan semakan kehakiman diberikan ruang dalam kes-kes berkaitan. Untuk tujuan tersebut, kaedah kualitatif digunakan dan kajian perpustakaan secara doktrin dilakukan untuk mengumpul data serta maklumat. Hasil kajian menunjukkan bahawa hak orang tahanan dan peranan mahkamah untuk membuat semakan kehakiman dalam kes-kes ekstremisme ganas adalah terhad di bawah undang-undang pencegahan tahanan Malaysia. Justeru, penulis mencadangkan supaya orang tahanan dan badan kehakiman diberikan kebebasan sepenuhnya untuk membuat semakan kehakiman bagi kes-kes ekstremisme ganas. Di samping itu, perlu ada kajian lanjut bagi membandingkan pendekatan semakan kehakiman di negara-negara lain dalam kes-kes ekstremisme ganas untuk dijadikan panduan agar peruntukan dalam undang-undang tahanan pencegahan Malaysia dapat dipinda atau diperbaiki demi menegakkan kedaulatan undang-undang

Modulating carboxymethylcellulose-based hydrogels with superior mechanical and rheological properties for future biomedical applications

Herein, a grafted copolymer composed of carboxymethylcellulose (CMC) and polyethylene-glycol-aminated (PEG-NH2) was successfully synthesized via a facile ionic interaction and scalable route in the presence of EDC/NHS (Nethyl-N′-(3-imethylaminopropyl)carbodiimide/N-hydroxysuccinimide) activators. From Fourier transform infrared (FTIR) spectroscopy, the absorption peak at 1652 cm–1 corresponded to –NH groups of PEG-NH2. After grafting, the grafted CMC-PEG was characterized for surface morphology, crystallinity, functional groups determination, and thermal analysis. No cytotoxicity effect was observed in normal human dermal fibroblasts (NHDFs) cells following exposure to the grafted CMC-PEG up to 2 mg/ml. The rheological studies suggested that the optimized 10% (w/v) grafted CMC-PEG hydrogels crosslinked with 5% (w/v) citric acid (CA) exhibited better mechanical properties compared to the non-grafted CMC. This work highlights the characterizations of grafted CMC-PEG and demonstrates the potential of grafted CMC-PEG hydrogels crosslinked with CA for advanced 3D-bioprinting or as injectable hydrogels in various biomedical applications such as tissue engineering, wound dressing materials, and drug delivery systems

Radiation cross-linked carboxymethyl sago pulp hydrogels loaded with ciprofloxacin: Influence of irradiation on gel fraction, entrapped drug and in vitro release

Carboxymethyl sago pulp (CMSP) with 0.4 DS, viscosity 184 dl/g and molecular weight 76,000 g/mol was synthesized from sago waste. 10 and 20% w/v solutions of CMSP were irradiated at 10–30 kGy to form hydrogels and were characterized by % gel fraction (GF). Irradiation of 20% CMSP using 25 kGy has produced stable hydrogels with the highest % GF and hence loaded with ciprofloxacin HCl. Drug-loaded hydrogels were produced by irradiating the mixture of drug and 20% CMSP solution at 25 kGy. After irradiation, the hydrogels were cut into circular discs with a diameter of 671 mm and evaluated for physicochemical properties as well as drug release kinetics. The ciprofloxacin loading in the disc was 14.7%71 w/w with an entrapment efficiency of 73.5% w/w. The low standard deviation of drug-loaded discs indicated uniform thickness (1.570.3 mm). The unloaded discs were thinner (170.4 mm) and more brittle than the drug-loaded discs. FESEM, FT-IR, XRD, DSC and TGA analysis revealed the absence of polymer–drug interaction and transformation of crystalline to amorphous form of ciprofloxacin in the discs. The disc sustained the drug release in phosphate buffer pH 7.4 over 36 h in a first-order manner. The mechanism of the drug release was found to be swelling controlled diffusion and matrix erosion. The anti-bacterial effect of ciprofloxacin was retained after irradiation and CMSP disc could be a promising device for ocular drug delivery

Preparation of carboxymethyl sago pulp hydrogel from sago waste by electron beam irradiation and swelling behavior in water and various pH media.

Solutions of carboxymethyl sago pulp (CMSP) of various degree of substitution were irradiated with electron beam of various radiation doses. The gelation dose (Dg) and po/qo ratio (po is degradation density, qo is crosslinking density) is dependent on CMSP concentration and degree of substitution. In the range of concentrations of 10% to 80% (w/v) CMSP with degree of substitutions of 0.4, 0.6, and 0.8, the po/qo ratio decreases with increasing %CMSP showing that crosslinking processes are dominating and increasing the gel network of the CMSP hydrogel. The fourier transform infrared spectra of CMSP hydrogels of degree of substitutions of 0.4, 0.6, and 0.8 with percentage of gel fractions 25, 35, and ≥ 40 show differences in the intensity of the absorption bands at 1020–1100, 1326, and 1422 cm−1 with different degree of substitutions and percentage of gel fraction (%GF) that correspond to different extents of chain scission and crosslinking. The swelling behavior in water shows that CMSP hydrogels could absorb 3500–5300% of water by 1 g of CMSP hydrogel. The ability to absorb water increases with the decrease of degree of substitution and %GF of the CMSP hydrogels. It is also observed that the optimum pH for swelling CMSP hydrogel is at pH 7

Development of polymer-assisted nanoparticles and nanogels for cancer therapy: An update

With cancer remaining as one of the main causes of deaths worldwide, many studies are undergoing the effort to look for a novel and potent anticancer drug. Nanoparticles (NPs) are one of the rising fields in research for anticancer drug development. One of the key advantages of using NPs for cancer therapy is its high flexibility for modification, hence additional properties can be added to the NPs in order to improve its anticancer action. Polymer has attracted considerable attention to be used as a material to enhance the bioactivity of the NPs. Nanogels, which are NPs cross-linked with hydrophilic polymer network have also exhibited benefits in anticancer application. The characteristics of these nanomaterials include non-toxic, environment-friendly, and variable physiochemical properties. Some other unique properties of polymers are also attributed by diverse methods of polymer synthesis. This then contributes to the unique properties of the nanodrugs. This review article provides an in-depth update on the development of polymer-assisted NPs and nanogels for cancer therapy. Topics such as the synthesis, usage, and properties of the nanomaterials are discussed along with their mechanisms and functions in anticancer application. The advantages and limitations are also discussed in this article