Displaying publications 1 - 20 of 44 in total

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  1. Gong J, Hou L, Ching YC, Ching KY, Hai ND, Chuah CH
    Int J Biol Macromol, 2024 Apr;264(Pt 2):130525.
    PMID: 38431004 DOI: 10.1016/j.ijbiomac.2024.130525
    To realize the maximum therapeutic activity of medicine and protect the body from the adverse effects of active ingredients, drug delivery systems (DDS) featured with targeted transportation sites and controllable release have captured extensive attention over the past decades. Hydrogels with unique three-dimensional (3D) porous structures present tunable capacity, controllable degradation, various stimuli sensitivity, therapeutic agents encapsulation, and loaded drugs protection properties, which endow hydrogels with bred-in-the-bone advantages as vehicles for drug delivery. In recent years, with the impressive consciousness of the "back-to-nature" concept, biomass materials are becoming the 'rising star' as the hydrogels building blocks for controlled drug release carriers due to their biodegradability, biocompatibility, and non-toxicity properties. In particular, cellulose and its derivatives are promising candidates for fabricating hydrogels as their rich sources and high availability, and various smart cellulose-based hydrogels as targeted carriers under exogenous such as light, electric field, and magnetic field or endogenous such as pH, temperature, ionic strength, and redox gradients. In this review, we summarized the main synthetic strategies of smart cellulose-based hydrogels including physical and chemical cross-linking, and illustrated the detailed intelligent-responsive mechanism of hydrogels in DDS under external stimulus. Additionally, the ongoing development and challenges of cellulose-based hydrogels in the biomedical field are also presented.
  2. Yahya M, Sakti SCW, Fahmi MZ, Chuah CH, Lee HV
    Int J Biol Macromol, 2024 Feb;257(Pt 2):128696.
    PMID: 38072349 DOI: 10.1016/j.ijbiomac.2023.128696
    This study focuses on the preparation of mangosteen rind-derived nanocellulose via green ascorbic acid hydrolysis. Subsequently, milk protein-grafted nanocellulose particles were developed as a renewable Pickering emulsifier for water-oil stabilization. The stabilizing efficiency of modified nanocellulose (NC-S) at different caseinate (milk protein) concentrations (1.5, 3.0, and 4.0 % w/v) was tested in a water-in-oil emulsion (W/O ratio of 40:60). At a concentration 3.0 % w/v of caseinate (3.0NC-S), the emulsion exhibited a stronger network of adsorption between water, Pickering emulsifier, and oil. This resulted in reduced oil droplet flocculation, increased stability over a longer period, and favorable emulsifying properties, as depicted in the creaming index profile, oil droplet distribution, and rheology analysis. Since 3.0NC-S demonstrated the best colloidal stability, further focus will be placed on its microstructural properties, comparing them with those of mangosteen rind (MG), cellulose, and nanocellulose (NC-L). The XRD profile indicated that both NC-L and NC-S possessed a cellulose nanocrystal structure characterized as type I beta with a high crystallinity index above 60 %. Morphology investigation shown that the NC-L present in the spherical shape of particles with nanosized ranging at diameters of 11.27 ± 0.50 nm and length 11.76 ± 0.46 nm, while modified NC-S showed increase sized at 14.26 ± 4.60 nm and length 14.96 ± 4.94 nm. The increment of particle sizes from NC-L to NC-S indicated 2.82 × 10-15 mg/m2 of surface protein coverage by caseinate functional groups.
  3. Gunathilake TMSU, Ching YC, Uyama H, Hai ND, Chuah CH
    Cellulose (Lond), 2022 Jan 04.
    PMID: 35002106 DOI: 10.1007/s10570-021-04391-8
    Nanocellulose/polyvinyl alcohol/curcumin (CNC/PVA/curcumin) nanoparticles with enhanced drug loading properties were developed by the dispersion of nanocellulose in curcumin/polyvinyl alcohol aqueous medium. Due to the physical and chemical nature of sulphuric acid hydrolyzed nanocellulose and the antiviral properties of curcumin, the possibility of using these nanoparticles as an inhalable nanotherapeutic for the treatment of coronavirus disease 2019 (COVID-19) is discussed. The adsorption of curcumin and PVA into nanocellulose, and the presence of anionic sulphate groups, which is important for the interaction with viral glycoproteins were confirmed by Fourier transform infrared (FTIR) spectroscopy. FESEM images showed that the diameter of nanocellulose ranged from 50 to 100 nm, which is closer to the diameter (60-140 nm) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The solubility of poorly water-soluble curcumin was increased from 40.58 ± 1.42 to 313.61 ± 1.05 mg/L with increasing the PVA concentration from 0.05 to 0.8% (w/v) in aqueous medium. This is a significant increase in the solubility compared to curcumin's solubility in carboxymethyl cellulose medium in our previous study. The drug loading capacity increased by 22-fold with the addition of 0.8% PVA to the nanocellulose dispersed curcumin solution. The highest drug release increased from 1.25 ± 0.15 mg/L to 17.11 ± 0.22 mg/L with increasing the PVA concentration from 0 to 0.8% in the drug-loaded medium. Future studies of this material will be based on the antiviral efficacy against SARS-CoV-2 and cell cytotoxicity studies. Due to the particulate nature, morphology and size of SARS-CoV-2, nanoparticle-based strategies offer a strong approach to tackling this virus. Hence, we believe that the enhanced loading of curcumin in nanocellulose will provide a promising nano-based solution for the treatment of COVID-19.
  4. Gunathilake TMSU, Ching YC, Uyama H, Nguyen DH, Chuah CH
    Int J Biol Macromol, 2021 Dec 15;193(Pt B):1522-1531.
    PMID: 34740692 DOI: 10.1016/j.ijbiomac.2021.10.215
    The investigation of protein-nanoparticle interactions contributes to the understanding of nanoparticle bio-reactivity and creates a database of nanoparticles for use in nanomedicine, nanodiagnosis, and nanotherapy. In this study, hen's egg white was used as the protein source to study the interaction of proteins with sulphuric acid hydrolysed nanocellulose (CNC). Several techniques such as FTIR, zeta potential measurement, UV-vis spectroscopy, compressive strength, TGA, contact angle and FESEM provide valuable information in the protein-CNC interaction study. The presence of a broader peak in the 1600-1050 cm-1 range of CNC/egg white protein FTIR spectrum compared to the 1600-1050 cm-1 range of CNC sample indicated the binding of egg white protein to CNC surface. The contact angle with the glass surface decreased with the addition of CNC to egg white protein. The FESEM EDX spectra showed a higher amount of N and Na on the surface of CNC. It indicates the density of protein molecules higher around CNC. The zeta potential of CNC changed from -26.7 ± 0.46 to -21.7 ± 0.2 with the introduction of egg white protein due to the hydrogen bonding, polar bonds and electrostatic interaction between surface CNC and protein. The compressive strength of the egg white protein films increased from 0.064 ± 0.01 to 0.36 ± 0.02 MPa with increasing the CNC concentration from 0 to 4.73% (w/v). The thermal decomposition temperature of CNC/egg white protein decreased compared to egg white protein thermal decomposition temperature. According to UV-Vis spectroscopy, the far-UV light (207-222nm) absorption peak slightly changed in the CNC/egg white protein spectrum compared to the egg white protein spectrum. Based on the results, the observations of protein nanoparticle interactions provide an additional understanding, besides the theoretical simulations from previous studies. Also, the results indicate to aim CNC for the application of nanomedicine and nanotherapy. A new insight given by us in this research assumes a reasonable solution to these crucial applications.
  5. Chuah CH, Chow TS, Hor CP, Cheng JT, Ker HB, Lee HG, et al.
    Clin Infect Dis, 2021 Nov 19.
    PMID: 34849615 DOI: 10.1093/cid/ciab962
    BACKGROUND: Role of favipiravir in preventing disease progression in COVID-19 remains uncertain. We aimed to determine its effect in preventing disease progression from non-hypoxia to hypoxia among high risk COVID-19 patients.

    STUDY DESIGN: This was an open-label, randomized clinical trial conducted at 14 public hospitals across Malaysia from February to June 2021 among 500 symptomatic, RT-PCR confirmed COVID-19 patients, aged ≥50 years with ≥1 co-morbidity, and hospitalized within first 7 days of illness. Patients were randomized on 1:1 ratio to favipiravir plus standard care or standard care alone. Favipiravir was administered at 1800mg twice-daily on day 1 followed by 800mg twice-daily until day 5. The primary endpoint was rate of clinical progression from non-hypoxia to hypoxia. Secondary outcomes included rates of mechanical ventilation, intensive care unit (ICU) admission, and in-hospital mortality.

    RESULTS: Among 500 patients were randomized (mean age, 62.5 [SD 8.0] years; 258 women [51.6%]; and 251 [50.2%] had COVID-19 pneumonia), 487 (97.4%) patients completed the trial. Clinical progression to hypoxia occurred in 46 (18.4%) patients on favipiravir plus standard care and 37 (14.8%) on standard care alone (OR 1.30; 95%CI, 0.81-2.09; P=.28). All three pre-specified secondary end points were similar between both groups. Mechanical ventilation occurred in 6 (2.4%) vs 5 (2.0%) (OR 1.20; 95%CI, 0.36-4.23; P=.76), ICU admission in 13 (5.2%) vs 12 (4.8%) (OR 1.09; 95%CI, 0.48-2.47; P=.84), and in-hospital mortality in 5 (2.0%) vs 0 (OR 12.54; 95%CI, 0.76- 207.84; P=.08).

    CONCLUSIONS: Among COVID-19 patients at high risk of disease progression, early treatment with oral favipiravir did not prevent their disease progression from non-hypoxia to hypoxia.

  6. Gunathilake TMSU, Ching YC, Uyama H, Chuah CH
    J Drug Deliv Sci Technol, 2021 Aug;64:102634.
    PMID: 34127930 DOI: 10.1016/j.jddst.2021.102634
    Viral diseases have recently become a threat to human health and rapidly become a significant cause of mortality with a continually exacerbated unfavorable socio-economic impact. Coronaviruses, including severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome (MERS-CoV), and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), have threatened human life, with immense accompanying morbidity rates; the COVID-19 (caused by SARS-CoV-2) epidemic has become a severe threat to global public health. In addition, the design process of antiviral medications usually takes years before the treatments can be made readily available. Hence, it is necessary to invest scientifically and financially in a technology platform that can then be quickly repurposed on demand to be adequately positioned for this kind of pandemic situation through lessons learned from the previous pandemics. Nanomaterials/nanoformulations provide such platform technologies, and a proper investigation into their basic science and biological interactions would be of great benefit for potential vaccine and therapeutic development. In this respect, intelligent and advanced nano-based technologies provide specific physico-chemical properties, which can help fix the key issues related to the treatments of viral infections. This review aims to provide an overview of the latest research on the effective use of nanomaterials in the treatment of coronaviruses. Also raised are the problems, perspectives of antiviral nanoformulations, and the possibility of using nanomaterials effectively against current pandemic situations.
  7. Mhd Haniffa MAC, Munawar K, Ching YC, Illias HA, Chuah CH
    Chem Asian J, 2021 Jun 01;16(11):1281-1297.
    PMID: 33871151 DOI: 10.1002/asia.202100226
    New and emerging demand for polyurethane (PU) continues to rise over the years. The harmful isocyanate binding agents and their integrated PU products are at the height of environmental concerns, in particular PU (macro and micro) pollution and their degradation problems. Non-isocyanate poly(hydroxy urethane)s (NIPUs) are sustainable and green alternatives to conventional PUs. Since the introduction of NIPU in 1957, the market value of NIPU and its hybridized materials has increased exponentially in 2019 and is expected to continue to rise in the coming years. The secondary hydroxyl groups of these NIPU's urethane moiety have revolutionized them by allowing for adequate pre/post functionalization. This minireview highlights different strategies and advances in pre/post-functionalization used in biobased NIPU. We have performed a comprehensive evaluation of the development of new ideas in this field to achieve more efficient synthetic biobased hybridized NIPU processes through selective and kinetic understanding.
  8. Woon YL, Lee YL, Chong YM, Ayub NA, Krishnabahawan SL, Lau JFW, et al.
    Lancet Reg Health West Pac, 2021 Apr;9:100123.
    PMID: 33778796 DOI: 10.1016/j.lanwpc.2021.100123
    Background: Asymptomatic severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infections are well documented. Healthcare workers (HCW) are at increased risk of infection due to occupational exposure to infected patients. We aim to determine the prevalence of SARS-CoV-2 antibodies among HCW who did not come to medical attention.

    Methods: We prospectively recruited 400 HCW from the National Public Health Laboratory and two COVID-19 designated public hospitals in Klang Valley, Malaysia between 13/4/2020 and 12/5/2020. Quota sampling was used to ensure representativeness of HCW involved in direct and indirect patient care. All participants answered a self-administered questionnaire and blood samples were taken to test for SARS-CoV-2 antibodies by surrogate virus neutralization test.

    Findings: The study population comprised 154 (38.5%) nurses, 103 (25.8%) medical doctors, 47 (11.8%) laboratory technologists and others (23.9%). A majority (68.9%) reported exposure to SARS-CoV-2 in the past month within their respective workplaces. Adherence to personal protection equipment (PPE) guidelines and hand hygiene were good, ranging from 91-100% compliance. None (95% CI: 0, 0.0095) of the participants had SARS-CoV-2 antibodies detected, despite 182 (45.5%) reporting some symptoms one month prior to study recruitment. One hundred and fifteen (29%) of participants claimed to have had contact with known COVID-19 persons outside of their workplace.

    Interpretation: Zero seroprevalence among HCW suggests a low incidence of undiagnosed COVID-19 infection in our healthcare setting during the first local wave of SARS-CoV-2 infection. The occupational risk of SARS-CoV-2 transmission within healthcare facilities can be prevented by adherence to infection control measures and appropriate use of PPE.

  9. Chuah CH, Gani Y, Sim B, Chidambaram SK
    J R Coll Physicians Edinb, 2021 03;51(1):24-30.
    PMID: 33877130 DOI: 10.4997/JRCPE.2021.107
    BACKGROUND: Carbapenem-resistant Enterobacteriaceae (CRE) infection has become a major challenge to clinicians. The aim of this study is to identify the risk factors of acquiring CRE to guide more targeted screening for hospital admissions.

    METHODS: This is a retrospective case-control study (ratio 1:1) where a patient with CRE infection or colonisation was matched with a control. The control was an individual who tested negative for CRE but was a close contact of a patient testing positive and was admitted at the same time and place. Univariate and multivariate statistical analyses were done.

    RESULTS: The study included 154 patients. The majority of the CRE was Klebsiella species (83%). From univariate analysis, the significant risk factors were having a history of indwelling devices (OR: 2.791; 95% CI: 1.384-5.629), concomitant other MDRO (OR: 2.556; 95% CI: 1.144-5.707) and hospitalisation for more than three weeks (OR: 2.331; 95% CI: 1.163-4.673). Multivariate analysis showed that being unable to ambulate on admission (adjusted OR: 2.345; 95% CI: 1.170-4.699) and antibiotic exposure (adjusted OR: 3.515; 95% CI: 1.377-8.972) were independent predictors. The in-hospital mortality rate of CRE infection was high (64.5%). CRE acquisition resulted in prolonged hospitalisation (median=35 days; P<0.001).

    CONCLUSION: CRE infection results in high morbidity and mortality. On top of the common risk factors, patients with mobility restriction, prior antibiotic exposures and hospitalisation for more than three weeks should be prioritised in the screening strategy to control the spread of CRE.

  10. Shi W, Ching YC, Chuah CH
    Int J Biol Macromol, 2021 Feb 15;170:751-767.
    PMID: 33412201 DOI: 10.1016/j.ijbiomac.2020.12.214
    Spherical aerogels are not easily broken during use and are easier to transport and store which can be used as templates for drug delivery. This review summarizes the possible approaches for the preparation of aerogel beads and microspheres based on chitosan and cellulose, an overview to the methods of manufacturing droplets is presented, afterwards, the transition mechanisms from sol to a spherical gel are reviewed in detail followed by different drying processes to obtain spherical aerogels with porous structures. Additionally, a specific focus is given to aerogel beads and microspheres to be regarded as drug delivery carriers. Furthermore, a core/shell architecture of aerogel beads and microspheres for controlled drug release is described and subjected to inspire readers to create novel drug release system. Finally, the conclusions and outlooks of aerogel beads and microspheres for drug delivery are summarized.
  11. Mhd Haniffa MAC, Ching YC, Illias HA, Munawar K, Ibrahim S, Nguyen DH, et al.
    Carbohydr Polym, 2021 Feb 01;253:117245.
    PMID: 33279000 DOI: 10.1016/j.carbpol.2020.117245
    Cellulose with ample hydroxyl groups is considered as a promising supportive biopolymer for fabricating cellulose supported promising magnetic sorbents (CMS) for magnetic solid-phase extraction (MSPE). The easy recovery via external magnetic field, and recyclability of CMS, associated with different types and surface modifications of cellulose has made them a promising sorbent in the field of solid-phase extraction. CMS based sorbent can offer improved adsorption and absorption capabilities due to its high specific surface area, porous structure, and magnetic attraction feature. This review mainly focuses on the fabrication strategies of CMS using magnetic nanoparticles (MNPs) and various forms of cellulose as a heterogeneous and homogeneous solution either in alkaline mediated urea or Ionic liquids (ILs). Moreover, CMS will be elaborated based on their structures, synthesis, physical performance, and chemical attraction of MNPs and their MSPE in details. The advantages, challenges, and prospects of CMS in future applications are also presented.
  12. Yang J, Ching YC, Chuah CH, Liou NS
    Polymers (Basel), 2020 Dec 29;13(1).
    PMID: 33383626 DOI: 10.3390/polym13010094
    This study examined the development of starch/oil palm empty fruit bunch-based bioplastic composites reinforced with either epoxidized palm oil (EPO) or epoxidized soybean oil (ESO), at various concentrations, in order to improve the mechanical and water-resistance properties of the bio-composites. The SEM micrographs showed that low content (0.75 wt%) of epoxidized oils (EOs), especially ESO, improved the compatibility of the composites, while high content (3 wt%) of EO induced many voids. The melting temperature of the composites was increased by the incorporation of both EOs. Thermal stability of the bioplastics was increased by the introduction of ESO. Low contents of EO led to a huge enhancement of tensile strength, while higher contents of EO showed a negative effect, due to the phase separation. The tensile strength increased from 0.83 MPa of the control sample to 3.92 and 5.42 MPa for the composites with 1.5 wt% EPO and 0.75 wt% ESO, respectively. EOs reduced the composites' water uptake and solubility but increased the water vapor permeability. Overall, the reinforcing effect of ESO was better than EPO. These results suggested that both EOs can be utilized as modifiers to prepare starch/empty-fruit-bunch-based bioplastic composites with enhanced properties.
  13. Gunathilake TMSU, Ching YC, Chuah CH, Hai ND, Nai-Shang L
    Pharm Res, 2020 Aug 30;37(9):178.
    PMID: 32864721 DOI: 10.1007/s11095-020-02910-z
    PURPOSE: Among various types of external stimuli-responsive DDS, electric-responsive DDS are more promising carriers as they exploit less complex, easily miniaturized electric signal generators and the possibility of fine-tuning the electric signals. This study investigates the use of intrinsically biocompatible biopolymers in electro-simulative drug delivery to enhance the release of poorly-soluble/non-ionic drug.

    METHODS: CMC/PLA/ZnO/CUR nanocomposite films were prepared by the dispersion of CMC and ZnO NPs in solubilized PLA/curcumin medium, followed by solvent casting step. Curcumin is poorly water-soluble and used as the model drug in this study. The films with different contents of CMC, PLA and ZnO NPs were characterized using FTIR, impedance spectroscopy, tensile testing and FESEM imaging. The in vitro drug release of the films was carried out in deionized water under DC electric field of 4.5 V.

    RESULTS: The ionic conductivity of the films increased with increasing the CMC concentration of the film. The addition of a small amount of ZnO NPs (2%) successfully restored the tensile properties of the film. In response to the application of the electric field, the composite films released drug with a near-linear profile. There was no noticeable amount of passive diffusion of the drug from the film with the absence of the electric field.

    CONCLUSION: The outcome of this study enabled the design of an electric-responsive nanocomposite platform for the delivery of poorly water-soluble/non-ionic drugs. Graphical abstract.

  14. Chuah CH, Ong YC, Kong BH, Woo YY, Wong PS, Leong KN, et al.
    J R Coll Physicians Edinb, 2020 Jun;50(2):138-140.
    PMID: 32568283 DOI: 10.4997/JRCPE.2020.211
    Talaromycosis typically occurs as an opportunistic infection among immunocompromised individuals. Infection caused by species other than T. marneffei is uncommon. While most reported cases describe infection in the lungs, we report an extremely rare intracranial Talaromyces species infection. This 61-year-old with end-stage renal disease who was unwell for the previous two months, presented with fever and worsening confusion lasting for three days. Lumbar puncture was suggestive of meningitis. Cerebrospinal fluid (CSF) culture was later confirmed to be Penicillium chrysogenum. The patient was co-infected with Group B Streptococcus sepsis. He improved with amphotericin B and ceftriaxone and was discharged with oral itraconazole for four weeks. However, he died of unknown causes two weeks later at home. Talaromyces species infection in the central nervous system is uncommon. This case highlighted a rare but life-threatening fungal meningitis. Among the four reported cases worldwide, none of the patients survived.
  15. Haniffa MACM, Illias HA, Chee CY, Ibrahim S, Sandu V, Chuah CH
    ACS Omega, 2020 May 12;5(18):10315-10326.
    PMID: 32426588 DOI: 10.1021/acsomega.9b04388
    Hybrid bionanocomposite coating systems (HBCSs) are green polymer materials consisting of an interface between a coating matrix and nanoparticles. The coating matrix was prepared by using a nonisocyanate poly(hydroxyl urethane) (NIPHU) prepolymer crosslinked via 1,3-diaminopropane and epoxidized Jatropha curcas oil. TEMPO-oxidized cellulose nanoparticles (TARC) were prepared from microcrystalline cellulose, and (3-aminopropyl)trimethoxysilane (APTMS)-coated ZnO nanoparticles (APTMS-ZnO) and their suspensions were synthesized separately. The suspensions at different weight ratios were incorporated into the coating matrix to prepare a series of HBCSs. FT-IR, 1H-NMR, 13C-NMR, XRD, SEM, and TEM were used to confirm the chemical structures, morphology, and elements of the coating matrix, nanomaterials, and HBCSs. The thermomechanical properties of the HBCSs were investigated by TGA-DTG and pencil hardness analyses. The UV and IR absorption spectra of the HBCSs were obtained using UV-vis spectroscopy and FTIR spectroscopy, respectively. The HBCSs exhibited good thermal stability at about 200 °C. The degradation temperature at 5% mass loss of all samples was over around 280 °C. The HBCSs exhibited excellent UV block and IR active properties with a stoichiometric ratio of the NIPHU prepolymer and EJCO of 1:1 (wt/wt) containing 5 wt % TARC and 15 wt % APTMS-ZnO nanoparticles. It was observed that the sample with 5 wt % TARC and 15 wt % APTMS-ZnO (HBCS-2) exhibited a uniform crosslinking and reinforcement network with a T onset of 282 °C. This sample has successfully achieved good coating hardness and excellent UV and IR absorption.
  16. Sampath Udeni Gunathilake TM, Ching YC, Chuah CH, Rahman NA, Liou NS
    Int J Biol Macromol, 2020 May 07;158:670-688.
    PMID: 32389655 DOI: 10.1016/j.ijbiomac.2020.05.010
    The limitations of existing drug delivery systems (DDS) such as non-specific bio-distribution and poor selectivity have led to the exploration of a variety of carrier platforms to facilitate highly desirable and efficient drug delivery. Stimuli-responsive DDS are one of the most versatile and innovative approach to steer the compounds to the intended sites by exploiting their responsiveness to a range of various triggers. Preparation of stimuli-responsive DDS using celluloses and their derivatives offer a remarkable advantage over conventional polymer materials. In this review, we highlight on state-of-art progress in developing cellulose/cellulose hybrid stimuli-responsive DDS, which covers the preparation techniques, physicochemical properties, basic principles and, mechanisms of stimuli effect on drug release from various types of cellulose based carriers, through recent innovative investigations. Attention has been paid to endogenous stimuli (pH, temperature, redox gradient and ionic-strength) responsive DDS and exogenous stimuli (light, magnetic field and electric field) responsive DDS, where the cellulose-based materials have been extensively employed. Furthermore, the current challenges and future prospects of these DDS are also discussed at the end.
  17. Wei S, Ching YC, Chuah CH
    Carbohydr Polym, 2020 Mar 01;231:115744.
    PMID: 31888854 DOI: 10.1016/j.carbpol.2019.115744
    Chitosan with abundant functional groups is regarded as important ingredients for preparing aerogel materials in life science. The biocompatibility and biodegradability of chitosan aerogels, coupled to the variety of chemical functionalities they include, result in them promising carriers for drug delivery. Moreover, chitosan aerogels as drug delivery vehicles can offer improved drug bioavailability and drug loading capacity due to their highly porous network, considerably large specific surface area and polycationic feature. The major focus of this review lies in preparation methods of chitosan aerogels from acidic aqueous solution and chitosan solution in Ionic Liquids (ILs). In addition, chitosan aerogels as drug delivery carriers are introduced in detail and expected to inspire readers to create new kind of drug delivery system based on chitosan aerogels. Finally, growing points and perspectives of chitosan aerogels in drug delivery system are given.
  18. Yang J, Ching YC, Chuah CH
    Polymers (Basel), 2019 Apr 28;11(5).
    PMID: 31035331 DOI: 10.3390/polym11050751
    Lignocellulosic fibers and lignin are two of the most important natural bioresources in the world. They show tremendous potential to decrease energy utilization/pollution and improve biodegradability by replacing synthetic fibers in bioplastics. The compatibility between the fiber-matrix plays an important part in the properties of the bioplastics. The improvement of lignocellulosic fiber properties by most surface treatments generally removes lignin. Due to the environmental pollution and high cost of cellulose modification, focus has been directed toward the use of lignocellulosic fibers in bioplastics. In addition, lignin-reinforced bioplastics are fabricated with varying success. These applications confirm there is no need to remove lignin from lignocellulosic fibers when preparing the bioplastics from a technical point of view. In this review, characterizations of lignocellulosic fibers and lignin related to their applications in bioplastics are covered. Then, we generalize the developments and problems of lignin-reinforced bioplastics and modification of lignin to improve the interaction of lignin-matrix. As for lignocellulosic fiber-reinforced bioplastics, we place importance on the low compatibility of the lignocellulosic fiber-matrix. The applications of lignin-containing cellulose and lignocellulosic fibers without delignification in the bioplastics are reviewed. A comparison between lignocellulosic fibers and lignin in the bioplastics is given.
  19. Sampath Udeni Gunathilake TM, Ching YC, Chuah CH, Illias HA, Ching KY, Singh R, et al.
    Int J Biol Macromol, 2018 Oct 15;118(Pt A):1055-1064.
    PMID: 30001596 DOI: 10.1016/j.ijbiomac.2018.06.147
    Nanocellulose reinforced chitosan hydrogel was synthesized using chemical crosslinking method for the delivery of curcumin which is a poorly water-soluble drug. Curcumin extracted from the dried rhizomes of Curcuma longa was incorporated to the hydrogel via in situ loading method. A nonionic surfactant (Tween 20) was incorporated into the hydrogel to improve the solubility of curcumin. After the gas foaming process, hydrogel showed large interconnected pore structures. The release studies in gastric medium showed that the cumulative release of curcumin increased from 0.21% ± 0.02% to 54.85% ± 0.77% with the increasing of Tween 20 concentration from 0% to 30% (w/v) after 7.5 h. However, the entrapment efficiency percentage decreased with the addition of Tween 20. The gas foamed hydrogel showed higher initial burst release within the first 120 min compared to hydrogel formed at atmospheric condition. The solubility of curcumin would increase to 3.014 ± 0.041 mg/mL when the Tween 20 concentration increased to 3.2% (w/v) in simulated gastric medium. UV-visible spectra revealed that the drug retained its chemical activity after in vitro release. From these findings, it is believed that the nonionic surfactant incorporated chitosan/nanocellulose hydrogel can provide a platform to overcome current problems associated with curcumin delivery.
  20. Kok WM, Chuah CH, Cheng SF
    Food Sci Biotechnol, 2018 Apr;27(2):353-366.
    PMID: 30263758 DOI: 10.1007/s10068-017-0271-3
    A long chain saturated fatty acid (SFA), behenic acid, is incorporated into the sn-1, 3 positions of triacylglycerols in palm olein (POo) and high-oleic sunflower oil (HOS) by solvent-free interesterification catalyzed by Lipozyme RM IM. The enzymatic interesterified HOS (EIE-HOS) yielded 76.5% of BOO and BOB as compared to 45.6% in POo (EIE-POo). The sn-2 position of EIE-HOS displayed 5.3 mol% of SFA which is significantly lower compared to 13.5 mol% in EIE-POo (P 
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