Microwave assisted aloe vera coating on metallocen polyethylene for improving biocompatibility

Metallocene polyethylene (mPE) is known for its commendable physical and mechanical properties, but the problem of hemocompatibility hampers its clinical application. Therefore, an Aloe vera (AV) extract was coated on mPE assisted by microwave to rectify this problem. Initially, the duration of microwave treatment was optimized to 60 s by considering the weight degradation of the samples. Similarly, the coating time of fibrous AV extract was optimized to 12 h (A-12 h-mPE) and 24 h (A- 24 h-mPE) based on wettability increment. Fourier transform infrared (FTIR) spectra showed the addition of OH- groups and the vibration characteristic of several active constituents available in the AV coating. The decrease in mean contact angle of pristine mPE (P-mPE) from 88.43° to 32.93° in the A-24 h-mPE sample, depicts an increase in the wettability. Meanwhile, scanning electron microscopy (SEM) images displayed the presence of AV extract. The influence of microwave in enhancing the coating characteristics was investigated through Hirox 3D images, peel test, and degradation studies. In addition, an improvement in average surface roughness (Ra) of P-mPE from 2.069 nm to 7.796 nm for the A-24 h-mPE was interpreted through atomic force microscopy (AFM) analysis. Finally, the in vitro coagulation studies indicated a reasonable delay in blood clotting time on the AV coated mPE samples, which was presented by activated partial thromboplastin time (170 s) and prothrombin time (39 s) assay. The coated mPE samples also reduced hemolysis and platelet adhesion insinuating the potential usage of AV coated mPE in permanent and temporary blood contacting devices

Biomaterials in cardiovascular research: applications and clinical implications

Cardiovascular biomaterials (CB) dominate the category of biomaterials based on the demand and investments in this field. This review article classifies the CB into three major classes, namely, metals, polymers, and biological materials and collates the information about the CB. Blood compatibility is one of the major criteria which limit the use of biomaterials for cardiovascular application. Several key players are associated with blood compatibility and they are discussed in this paper. To enhance the compatibility of the CB, several surface modification strategies were in use currently. Some recent applications of surface modification technology on the materials for cardiovascular devices were also discussed for better understanding. Finally, the current trend of the CB, endothelization of the cardiac implants and utilization of induced human pluripotent stem cells (ihPSCs), is also presented in this review. The field of CB is growing constantly and many new investigators and researchers are developing interest in this domain. This review will serve as a one stop arrangement to quickly grasp the basic research in the field of C

Fabrication and hemocompatibility assessment of novel polyurethane-based bio-nanofibrous dressing loaded with honey and Carica papaya extract for the management of burn injuries

Management of burn injury is an onerous clinical task since it requires continuous monitoring and extensive usage of specialized facilities. Despite rapid improvizations and investments in burn management, >30% of victims hospitalized each year face severe morbidity and mortality. Excessive loss of body fluids, accumulation of exudate, and the development of septic shock are reported to be the main reasons for morbidity in burn victims. To assist burn wound management, a novel polyurethane (PU)-based bio-nanofibrous dressing loaded with honey (HN) and Carica papaya (PA) fruit extract was fabricated using a one-step electrospinning technique. The developed dressing material had a mean fiber diameter of 190±19.93 nm with pore sizes of 4-50 µm to support effective infiltration of nutrients and gas exchange. The successful blending of HN- and PA-based active biomolecules in PU was inferred through changes in surface chemistry. The blend subsequently increased the wettability (14%) and surface energy (24%) of the novel dressing. Ultimately, the presence of hydrophilic biomolecules and high porosity enhanced the water absorption ability of the PU-HN-PA nanofiber samples to 761.67% from 285.13% in PU. Furthermore, the ability of the bio-nanofibrous dressing to support specific protein adsorption (45%), delay thrombus formation, and reduce hemolysis demonstrated its nontoxic and compatible nature with the host tissues. In summary, the excellent physicochemical and hemocompatible properties of the developed PU-HN-PA dressing exhibit its potential in reducing the clinical complications associated with the treatment of burn injuries

Biodegradable mPEG-b-poly(MDO-co-vinyl esters) block copolymers as a viable nanocarrier platform with tuneable disassembly

Xanthate-based copolymerisations of 2-methylene-1,3-dioxepane (MDO) and vinyl acetate-derivative monomers were conducted using a versatile mPEG macroCTA to create degradable amphiphilic block copolymers that can undergo self-assembly and crosslinking reactions. Two different block copolymer systems were synthesised; one from vinyl bromobutanoate (VBr) that, after modification, would exhibit permanent crosslinking, and the other from vinyl levulinate (VL) that would have labile crosslinks under acidic pH. The copolymerisations of VBr exhibited excellent control over molecular weight, monomer incorporation and end-group retention, and were able to undergo nucleophilic substitution of the bromo-side chains to form azide-functional copolymers. Conversely, the VL copolymers tended to show less control over molecular weight and end group retention. However, both sets of copolymers were able to undergo self-assembly and with subsequent crosslinking under controlled conditions into micellar nanoparticles via strain promoted azide–alkyne cycloaddition (SPAAC) or hydrazone formation for the azide and ketone functional copolymers, respectively. These nanoparticle systems showed differing stabilities under hydrolytic degradation conditions though they contained a similar amount of degradable ester units in the polymer backbone. Depending on the crosslinking density, the reversible hydrazone linkages destabilized within a few days under physiological conditions (PBS, pH 7.4, 37 °C) as opposed to the stable SPAAC linkages which were intact over many days. Moreover, these materials resembling clinically relevant polycaprolactone (PCL) showed insignificant cytotoxicity towards mouse NIH-3T3 fibroblast and RAW264.7 macrophage cell lines, and displayed unique cellular drug delivery behaviour depending on the crosslinking system

Biodegradable mPEG-b-poly(MDO-co-vinyl esters) block copolymers as a viable nanocarrier platform with tuneable disassembly

Xanthate-based copolymerisations of 2-methylene-1,3-dioxepane (MDO) and vinyl acetate-derivative monomers were conducted using a versatile mPEG macroCTA to create degradable amphiphilic block copolymers that can undergo self-assembly and crosslinking reactions. Two different block copolymer systems were synthesised; one from vinyl bromobutanoate (VBr) that, after modification, would exhibit permanent crosslinking, and the other from vinyl levulinate (VL) that would have labile crosslinks under acidic pH. The copolymerisations of VBr exhibited excellent control over molecular weight, monomer incorporation and end-group retention, and were able to undergo nucleophilic substitution of the bromo-side chains to form azide-functional copolymers. Conversely, the VL copolymers tended to show less control over molecular weight and end group retention. However, both sets of copolymers were able to undergo self-assembly and with subsequent crosslinking under controlled conditions into micellar nanoparticles via strain promoted azide–alkyne cycloaddition (SPAAC) or hydrazone formation for the azide and ketone functional copolymers, respectively. These nanoparticle systems showed differing stabilities under hydrolytic degradation conditions though they contained a similar amount of degradable ester units in the polymer backbone. Depending on the crosslinking density, the reversible hydrazone linkages destabilized within a few days under physiological conditions (PBS, pH 7.4, 37 °C) as opposed to the stable SPAAC linkages which were intact over many days. Moreover, these materials resembling clinically relevant polycaprolactone (PCL) showed insignificant cytotoxicity towards mouse NIH-3T3 fibroblast and RAW264.7 macrophage cell lines, and displayed unique cellular drug delivery behaviour depending on the crosslinking system

Microwave-assisted fibrous decoration of mPE surface utilizing Aloe vera extract for tissue engineering applications

Developing multifaceted, biocompatible, artificial implants for tissue engineering is a growing field of research. In recent times, several works have been reported about the utilization of biomolecules in combination with synthetic materials to achieve this process. Accordingly, in this study, the ability of an extract obtained from Aloe vera, a commonly used medicinal plant in influencing the biocompatibility of artificial material, is scrutinized using metallocene polyethylene (mPE). The process of coating dense fibrous Aloe vera extract on the surface of mPE was carried out using microwaves. Then, several physicochemical and blood compatibility characterization experiments were performed to disclose the effects of corresponding surface modification. The Fourier transform infrared spectrum showed characteristic vibrations of several active constituents available in Aloe vera and exhibited peak shifts at far infrared regions due to aloe-based mineral deposition. Meanwhile, the contact angle analysis demonstrated a drastic increase in wettability of coated samples, which confirmed the presence of active components on glazed mPE surface. Moreover, the bio-mimic structure of Aloe vera fibers and the influence of microwaves in enhancing the coating characteristics were also meticulously displayed through scanning electron microscopy micrographs and Hirox 3D images. The existence of nanoscale roughness was interpreted through high-resolution profiles obtained from atomic force microscopy. And the extent of variations in irregularities was delineated by measuring average roughness. Aloe vera-induced enrichment in the hemocompatible properties of mPE was established by carrying out in vitro tests such as activated partial thromboplastin time, prothrombin time, platelet adhesion, and hemolysis assay. In conclusion, the Aloe vera-glazed mPE substrate was inferred to attain desirable properties required for multifaceted biomedical implants

Carbon nanotubes and graphene as emerging candidates in neuroregeneration and neurodrug delivery

Neuroregeneration is the regrowth or repair of nervous tissues, cells, or cell products involved in neurodegeneration and inflammatory diseases of the nervous system like Alzheimer’s disease and Parkinson’s disease. Nowadays, application of nanotechnology is commonly used in developing nanomedicines to advance pharmacokinetics and drug delivery exclusively for central nervous system pathologies. In addition, nanomedical advances are leading to therapies that disrupt disarranged protein aggregation in the central nervous system, deliver functional neuroprotective growth factors, and change the oxidative stress and excitotoxicity of affected neural tissues to regenerate the damaged neurons. Carbon nanotubes and graphene are allotropes of carbon that have been exploited by researchers because of their excellent physical properties and their ability to interface with neurons and neuronal circuits. This review describes the role of carbon nanotubes and graphene in neuroregeneration. In the future, it is hoped that the benefits of nanotechnologies will outweigh their risks, and that the next decade will present huge scope for developing and delivering technologies in the field of neuroscience

Gallic acid: prospects and molecular mechanisms of its anticancer activity

Cancer is the second leading cause of death worldwide. There is always a huge demand for novel anticancer drugs and scientists explore various natural and artificial compounds to overcome this. Gallic acid (GA) is one of the phenolic acids found in many dietary substances and herbs used in ancient medicine. It possesses antiinflammatory, antioxidant, antiviral and antibacterial properties. The present review summarizes the anticancer activity of GA and its derivatives. Various in vitro and in vivo experiments of GA against a variety of cancer cell lines were reported. The previous studies show that the anticancer activity of GA is related to the induction of apoptosis through different mechanisms like generation of reactive oxygen species (ROS), regulation of apoptotic and anti-apoptotic proteins, suppression and promotion of oncogenes, inhibition of matrix metalloproteinases (MMPs) and cell cycle arrest depending upon the type of cancer investigated. Conclusively, GA and its derivatives may be considered as a potent drug for cancer treatment alone as well as in combination with other anticancer drugs to increase the efficiency of chemotherapy. However, there is still a need for more experimentation in knock-out animal models and human clinical trials to promote and place GA and its derivatives on the commercial marke