Fazli Wahid

Advances in biomedical and pharmaceutical applications of functional bacterial cellulose-based nanocomposites

Bacterial cellulose (BC) synthesized by certain species of bacteria, is a fascinating biopolymer with unique physical and mechanical properties. BCs applications range from traditional dessert, gelling, stabilizing and thickening agent in the food industry to advanced high-tech applications, such as immobilization of enzymes, bacteria and fungi, tissue engineering, heart valve prosthesis, artificial blood vessels, bone, cartilage, cornea and skin, and dental root treatment. Various BC-composites have been designed and investigated in order to enhance its biological applicability. This review focuses on the application of BC-based composites for microbial control, wound dressing, cardiovascular, ophthalmic, skeletal, and endodontics systems. Moreover, applications in controlled drug delivery, biosensors/bioanalysis, immobilization of enzymes and cells, stem cell therapy and skin tissue repair are also highlighted. This review will provide new insights for academia and industry to further assess the BC-based composites in terms of practical applications and future commercialization for biomedical and pharmaceutical purposes.

Removal of reactive blue 19 dye by sono, photo and sonophotocatalytic oxidation using visible light.

An efficient sonophotocatalytic degradation of reactive blue 19 (RB 19) dye was successfully carried out using sulfur-doped TiO2 (S-TiO2) nanoparticles. The effect of various treatment processes that is sonolysis, photolysis, catalysis, sonocatalysis, photocatalysis, and sonophotocatalysis were investigated for RB 19 removal. S-TiO2 were synthesized in 1, 3 and 5 wt.% of sulfur by sol-gel process and characterized by X-ray diffraction (XRD) and scanning electron microscopy coupled with energy dispersive X-ray (SEM-EDX), UV-Visible diffuse reflectance spectra (DRS). The results confirm anatase phase of TiO2, porous agglomerate structure, and a red shift in the absorbance spectra of S-TiO2. The dye degradation was studied by using UV-Vis spectrophotometer at λ max=594 nm. The reaction parameters such as pH, catalyst dosage, initial dye concentration, ultrasonic power and effect of sulfur doping in different weight percent were studied to find out the optimum degradation conditions. Optimum conditions were found as: S-TiO2=5 wt.%, catalyst (S-TiO2 5 wt.%)=50mg, RB 19 solution concentration=20 mg L(-1), pH=3, ultrasound power=100 and operating temperature=25°C. The response of 5 wt.% S-TiO2 was found better than 1 and 3 wt.% S-TiO2 and other forms TiO2. The sonophotocatalysis process was superior to other methods. During this process the ultrasound cavitation and photocatalysis water splitting takes place which leads to the generation of OH. As reveled by the GCMS results the reactive blue 19 (20 mg L(-1)) was degraded to 90% within 120 min. The S-TiO2 sonophotocatalysis system was studied for the first time for dye degradation and was found practicable, efficient and cost effective for the degradation of complex and resistant dyes such as RB19.

Bacterial cellulose-zinc oxide nanocomposites as a novel dressing system for burn wounds

Bacterial cellulose possesses physical and mechanical properties of an ideal wound dressing material but lack of antimicrobial activity limits its biomedical applications. Therefore, in current study, the inherent wound healing characteristics of bacterial cellulose and antimicrobial properties of zinc oxide nanoparticles were combined. The reinforcement (impregnation) of zinc oxide nanoparticles into bacterial cellulose sheets was confirmed through various characterization techniques. The antimicrobial capacity of bacterial cellulose-zinc oxide nanocomposites was tested against common burn pathogens. The in-vivo wound healing and tissue regeneration of the nanocomposites was investigated in burn BALBc mice model. Characterization techniques confirmed the successful impregnation of nanoparticles into bacterial cellulose. Bacterial cellulose-zinc oxide nanocomposites exhibited 90%, 87.4%, 94.3% and 90.9% activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Citrobacter freundii, respectively. Bacterial cellulose-zinc oxide nanocomposites treated animals showed significant (66%) healing activity. The histological analysis revealed fine tissue regeneration in composites treated group. These findings suggest that bacterial cellulose-zinc oxide nanocomposites could be a novel dressing material for burns.

MicroRNA and diseases: Therapeutic potential as new generation of drugs

MicroRNA (miRNA) is a small non-coding regulatory RNA of 21-25 nucleotides (nts) in length. miRNA works as a post-transcriptional regulator of a specific mRNA by inducing degradation or translation repression resulting in gene silencing. A large number of miRNA have been reported and many more are yet to be discovered. Aberrant expression of miRNA has been linked to numerous diseases. Attempts have been made to attenuate miRNA misregulation under pathophysiological conditions. Additionally, the potential use of miRNA in the diagnosis and treatment of diseases has been studied. Several preclinical and clinical results have been obtained, and miRNA-based therapeutics are still under investigations. In this review, the role of miRNA in a variety of pathological conditions has been summarized. Recent findings from preclinical and clinical investigations examining the role of miRNA as diagnostic markers, and their potential as drug candidates, are also highlighted. The current results summarized in this review may elucidate new dimensions of miRNA therapeutic and diagnostic techniques for biomedical academic and industry research.

Production, Characterization and Physico-mechanical Properties of Bacterial Cellulose from Industrial Wastes

In the current study, two different alternative media including black strap molasses (BSM) and molasses from condensation unit of brewery industry (MB) were evaluated for production of bacterial cellulose (BC) in comparison to chemically defined Hestrin–Schramm (HS) medium as a control under static and shaking conditions. In static culture, the BC production was 2.90, 1.74, 2.41xa0g/l for BSM, MB and HS media, respectively after 9xa0days of cultivation. The production slightly increased to 3.05, 1.78, 2.49xa0g/l for BSM, MB and HS media, respectively under shaking conditions after 9xa0days. The chemical structure of BC samples was confirmed through FTIR and XRD analysis. FE-SEM analysis revealed slightly loose fibril arrangement in BSM–BC and MB–BC compared to HS–BC. Water holding capacity was in order of BSM–BCxa0>xa0MB–BCxa0>xa0HS–BC. The mechanical and thermal properties of BSM–BC and MB–BC were slightly lower than the HS–BC.

Production, characterization and biological features of bacterial cellulose from scum obtained during preparation of sugarcane jaggery (gur)

Bacterial cellulose (BC) has been given an ample attention due to its high potential for many industrial applications. However, the high cost of production medium has hindered the commercialization of BC. Several efforts have been made to explore cheep, raw and waste sources for BC production. The current study aims at investigating the BC production from a waste source; the scum obtained during preparation of sugarcane jaggery or gur (JS). JS was five-fold diluted with distilled water and used as culturing medium without any additional nutrients. The production of BC was monitored till 10th days of cultivation both at static and shaking culturing conditions. A maximum of 2.51xa0g/L and 2.13xa0g/L BC was produced in shaking and static cultures, respectively, after 10xa0days. The structure features of BC were confirmed through FTIR, XRD and SEM analysis. The chemical structure and physical appearance strongly resembled the BC produced form synthetic media. It was noteworthy that the BC produced from JS showed higher mechanical and thermal properties. The cell adhesion and proliferation capabilities of produced BC were observed that depicted definite animal cell adhesion without any considerable cytotoxicity. Besides providing an economically feasible way for BC production, the high level of physico-mechanical and biological properties insured the importance in medical fields.

Therapeutic potential of curcumin for multiple sclerosis

Multiple sclerosis (MS) is a chronic autoimmune inflammatory disease of the central nervous system (CNS), characterized by demyelination, neuronal injury, and breaching of the blood-brain barrier (BBB). Epidemiological studies have shown that immunological, genetic, and environmental factors contribute to the progression and development of MS. T helper 17 (Th17) cells are crucial immunological participant in the pathophysiology of MS. The aberrant production of IL-17 and IL-22 by Th17 cells crosses BBB promotes its disruption and interferes with transmission of nerve signals through activation of neuroinflammation in the CNS. These inflammatory responses promote demyelination through transcriptional activation of signal transducers and activators of transcription-1 (STAT-1), nuclear factor kappa-B (NF-κB), matrix metalloproteinases (MMPs), interferon ϒ (IFNϒ), and Src homology region 2 domain-containing phosphatase-1 (SHP-1). B cells also contribute to disease progression through abnormal regulation of antibodies, cytokines, and antigen presentation. Additionally, oxidative stress has been known as a causative agent for the MS. Curcumin is a hydrophobic yellowish diphenolic component of turmeric, which can interact and modulate multiple cell signaling pathways and prevent the development of various autoimmune neurological diseases including MS. Studies have reported curcumin as a potent anti-inflammatory, antioxidant agent that could modulate cell cycle regulatory proteins, enzymes, cytokines, and transcription factors in CNS-related disorders including MS. The current study summarizes the reported knowledge on therapeutic potential of curcumin against MS, with future indication as neuroprotective and neuropharmacological drug.

Bacterial cellulose–TiO2 nanocomposites promote healing and tissue regeneration in burn mice model

The development of novel cutaneous wound treatments particularly for burns is of paramount importance due to complex pathophysiology, prevalent infection and clinical complexities associated with burn care. The main focus of the current study was to investigate the in vivo burn wound healing potential of bacterial cellulose (BC) and titanium dioxide (TiO2) nanocomposites (BC–TiO2). The physicochemical characterization of BC–TiO2 was carried out using FE-SEM, XRD and FT-IR. The antimicrobial activity of the nanocomposite was tested against Escherichia coli and Staphylococcus aureus through agar disc diffusion protocol. The in vivo wound healing efficacy was evaluated in burn wound model through wound area measurement, percent contraction and histopathology. The characterization results confirmed the successful incorporation of TiO2 nanoparticles into BC. The nanocomposites exhibited 81 ± 0.4% and 83 ± 0% inhibition against E. coli and S. aureus, respectively. The composite bandage showed good healing pattern with 71 ± 2.41% wound contraction. Histopathological evidence like the formation of healthy granulation tissue and the re-epithelization indicated the healing progression in the composite treated group. In comparison, the BC treated group has partial epithelization and signs of inflammation. These results proved that the composite dressing possesses an excellent healing potential with faster re-epithelization rate and accelerated wound contraction ability and thus could be a candidate for the development of cutaneous wound care products to address the limitations of the conventional wound dressing for burns.

Intestinal and vascular smooth muscle relaxant effect of Viscum album explains its medicinal use in hyperactive gut disorders and hypertension

BackgroundViscum album has shown inhibitory effect on different smooth muscles but underlying mechanisms in gut and vascular smooth muscles are not well defined. Additionally, the plant has also importance in managing hyperactive gut and cardiovascular disorders. The current study was aimed to probe a pharmacological base of the smooth muscle relaxant effect of V. album in gut and vascular preparations.MethodsV. album crude extract (Va. Cr) and its ethyl acetate fraction (Va. EtAc) were studied using in vitro techniques. The antispasmodic activity was performed using isolated rabbit jejunum while the vasorelaxant effects were studied in rabbit aortic rings.ResultsVa. Cr and Va. EtAc inhibited spontaneous and high K+-induced contractions with EC50 values of 0.31xa0mg/mL (0.15–0.57) and 0.62xa0mg/mL (0.3–0.95), respectively. This advocates an antispasmodic effect probably operated through calcium channels blockade (CBB). The proposed mechanism was confirmed by a pretreatment of the tissue with Va. Cr (0.01–0.3xa0mg/mL), which shifted the Ca++ concentration-response curves (CRCs) rightward, similar to verapamil. Moreover, Va. Cr showed a partial relaxation against high K+ and PE (1xa0μM) induced contractions in isolated rabbit aorta rings. Va. EtAc caused complete relaxation of high K+ precontraction and partially relaxed PE (1xa0μM) induced contractions, suggesting inhibitory effect on Ca++ entry, in addition to other possible mechanisms. CRCs were shifted to the right correspondingly to verapamil when the aortic rings were pretreated with Va. Cr and Va. EtAc.ConclusionsThese data indicated that Va. Cr possesses smooth muscle relaxant effect mediated through voltage-dependent Ca++ channel blockade (CCB), which explains its spasmolytic and vasorelaxant activity. The CCB activity is concentrated more in Va. EtAc. This study provides an evidence for the medicinal importance of V. album in gut spasm and possibly hypertension.

Phytochemical analysis and effects of Pteris vittata extract on visual processes

The present study was designed to explore the possible effects of Pteris vittata on visual sensitivity, ERG waves, and other components of the visual system. Electrophysiological techniques including electroretinography (ERG) were used in the present study. The phytochemical composition of the extract was investigated using liquid chromatography–mass spectrometry (LC–MS) techniques. The results indicated that the extract significantly augmented dark- and light-adapted ERG b-wave amplitude. Furthermore, these findings showed that P. vittata extract does not have Gamma-aminobutyric acid receptor antagonistic activity but may function as a retinal neural antagonist in bullfrog retina. P. vittata extract improved the visual sensitivity by 0.8 log unit of light intensity, and reduced the regeneration time for rhodopsin. The six main peaks obtained through LC–MS were identified as flavonoids. Based on these results, it was concluded that P. vittata extract or its constituents may be used to treat eye diseases.