ABSTRACT
Even after the centenary celebration of insulin discovery, there prevail challenges concerning insulin aggregation, not only after repeated administration but also during industrial production, storage, transport, and delivery, significantly impacting protein quality, efficacy, and effectiveness. The aggregation reduces insulin bioavailability, increasing the risk of heightened immunogenicity, posing a threat to patient health, and creating a dent in the golden success story of insulin therapy. Insulin experiences various physicochemical and mechanical stresses due to modulations in pH, temperature, ionic strength, agitation, shear, and surface chemistry, during the upstream and downstream bioprocessing, resulting in insulin unfolding and subsequent fibrillation. This has fueled research in the pharmaceutical industry and academia to unveil the mechanistic insights of insulin aggregation in an attempt to devise rational strategies to regulate this unwanted phenomenon. The present review briefly describes the impacts of environmental factors of bioprocessing on the stability of insulin and correlates with various intermolecular interactions, particularly hydrophobic and electrostatic forces. The aggregation-prone regions of insulin are identified and interrelated with biophysical changes during stress conditions. The quest for novel additives, surface-active agents, and bioderived peptides in decelerating insulin aggregation, which results in overall structural stability, is described. We hope this review will help tackle the real-world challenges of insulin aggregation encountered during bioprocessing, ensuring safer, stable, and globally accessible insulin for efficient management of diabetes.
ABSTRACT
The unwanted phenomenon of protein fibrillation is observed in vivo and during therapeutic protein development in the industry. Protein aggregation is associated with various degenerative disorders and might induce immune-related challenges post-administration of biopharmaceutics. A pipeline for early detection, identification, and removal of pre-formed fibrils is needed to improve the quality, efficacy, and effectiveness of the formulation. Protein fibril formation is accompanied by unfolding, secondary structural changes and the formation of larger aggregates. However, most detection processes come with extensive sample preparation steps and inefficient repeatability, incurring a financial burden on research. The current article summarizes and critically discusses six simple yet powerful methods to detect aggregation phenomena in the line of detecting fibrillar aggregates in heat-induced bovine serum albumin protein. Comparing the native and heat-induced protein samples would provide insights about aggregates. Easy, inexpensive and optimized protocols for detecting the fibrillation of proteins are explained. The procedures mentioned here detected the appearance of ß-sheet-rich fibrils in the heat-induced protein sample. The aggregation is characterized by enhanced thioflavin-T fluorescence, alteration in the intrinsic fluorescence, decrease in helicity and subsequent increase in ß-sheet and appearance of particles with larger hydrodynamic diameters. â¢This article summarizes various analytical techniques to easily characterize the fibrillation of proteins.â¢Various techniques to detect the formation of ß-sheet rich structures, changes in the secondary structures and size of aggregates have been discussed.â¢The stated methodologies are validated on a model protein, albumin.
ABSTRACT
Given the significance of protein aggregation in proteinopathies and the development of therapeutic protein pharmaceuticals, revamped interest in assessing and modelling the aggregation kinetics has been observed. Quantitative analysis of aggregation includes data of gradual monomeric depletion followed by the formation of subvisible particles. Kinetic and thermodynamic studies are essential to gain key insights into the aggregation process. Despite being the medical marvel in the world of diabetes, insulin suffers from the challenge of aggregation. Physicochemical stresses are experienced by insulin during industrial formulation, storage, delivery, and transport, considerably impacting product quality, efficacy, and effectiveness. The present review briefly describes the pathways, mathematical kinetic models, and thermodynamics of protein misfolding and aggregation. With a specific focus on insulin, further discussions include the structural heterogeneity and modifications of the intermediates incurred during insulin fibrillation. Finally, different model equations to fit the kinetic data of insulin fibrillation are discussed. We believe that this review will shed light on the conditions that induce structural changes in insulin during the lag phase of fibrillation and will motivate scientists to devise strategies to block the initialization of the aggregation cascade. Subsequent abrogation of insulin fibrillation during bioprocessing will ensure stable and globally accessible insulin for efficient management of diabetes.
Subject(s)
Insulin , Proteostasis Deficiencies , Humans , Kinetics , Thermodynamics , Protein AggregatesABSTRACT
This study focuses on investigating the intriguing properties of Ca10(PO4)6(OH)2 (HAP)-K0.5Na0.5NbO3 (KNN) bioceramic composites, seeking to elucidate the relationship between their structural, electrical, biological, and optical behavior. The article begins with a close inspection of the O 1s spectra of the specimens obtained from X-ray photoelectron spectroscopy (XPS). The spectra reveal the peak related to lattice oxygen, O vacancy and the surface adsorbed O. The formed O vacancy strongly influences the changes in lattice parameters as observed from the X-ray diffraction (XRD) patterns. The frequency variation of the dielectric response for the composites in the radio frequency (RF) regime has electrical polarization effective for biomedical applications. Nyquist plots along with equivalent RC circuits further confirm that those electrical responses are mainly contributed from the grain boundaries. Adsorption dynamics of protein on the ceramic surface are investigated using bovine serum albumin (BSA), which established the major role of electrostatic interaction. Surface charge and O vacancies are modeled to understand the adsorption of protein and a linear correlation is reported. The role of O vacancies in modulating adsorption dynamics adds a new dimension to this study. The conformational change of BSA has also been considered by constructing the secondary structure following the protein-ceramic interaction. Excitingly, the composites are also found to be fluorescent active, a courtesy of the defects and vacancies leading to electron-hole recombination in the forbidden region. These promising properties envision an exciting future for HAP-KNN composites, especially in the domain of bioimaging and bone-tissue engineering.
Subject(s)
Ceramics , Serum Albumin, Bovine , Serum Albumin, Bovine/chemistry , Adsorption , Photoelectron Spectroscopy , Protein Structure, SecondaryABSTRACT
The increasing research and rapid developments in the field of exosomes provide insights into their role and significance in human health. Exosomes derived from various sources, such as mesenchymal stem cells, cardiac cells, and tumor cells, to name a few, can be potential therapeutic agents for the treatment of diseases and could also serve as biomarkers for the early detection of diseases. Cellular components of exosomes, several proteins, lipids, and miRNAs hold promise as novel biomarkers for the detection of various diseases. The structure of exosomes enables them as drug delivery vehicles. Since exosomes exhibit potential therapeutic applications, their efficient isolation from complex biological/clinical samples and precise real-time analysis becomes significant. With the advent of microfluidics, nano-biosensors are being designed to capture exosomes efficiently and rapidly. Herein, we have summarized the history, biogenesis, characteristics, functions, and applications of exosomes, along with the isolation, detection, and quantification techniques. The implications of surface modifications to enhance specificity have been outlined. The review also sheds light on the engineered nanoplatforms being developed for exosome detection and capture.
Subject(s)
Exosomes , Mesenchymal Stem Cells , MicroRNAs , Humans , Drug Delivery Systems , MicrofluidicsABSTRACT
Environment-benign synthesis of nanoparticles (NPs) are of great importance. Plant-based polyphenols (PPs) are electron donor analytes for the synthesis of metal and metal oxide NPs. This work produced and investigated iron oxide nanoparticles (IONPs) from PPs of tea leaves of Camellia sinensis var. assamica for Cr(VI) removal. The conditions for IONPs synthesis were using RSM CCD and found to be optimum at a time of 48 min, temperature of 26 °C, and iron precursors/leaves extract ratio (v/v) of 0.36. Further, these synthesized IONPs at a dosage of 0.75 g/L, temperature of 25 °C, and pH 2 achieved a maximum of 96% Cr(VI) removal from 40 mg/L of Cr(VI) concentration. The exothermic adsorption process followed the pseudo-second-order model, and Langmuir isotherm estimated a remarkable maximum adsorption capacity (Qm) of 1272 mg g-1 of IONPs. The proposed mechanistic for Cr(VI) removal and detoxification involved adsorption and its reduction to Cr(III), followed by Cr(III)/Fe(III) co-precipitation.
Subject(s)
Camellia sinensis , Metal Nanoparticles , Water Pollutants, Chemical , Ferric Compounds , Adsorption , Hydrogen-Ion Concentration , Kinetics , Chromium , Oxides , Magnetic Iron Oxide NanoparticlesABSTRACT
Small interfering RNA (siRNA)-mediated mRNA degradation approach have imparted its eminence against several difficult-to-treat genetic disorders and other allied diseases. Viral outbreaks and resulting pandemics have repeatedly threatened public health and questioned human preparedness at the forefront of drug design and biomedical readiness. During the recent pandemic caused by the SARS-CoV-2, mRNA-based vaccination strategies have paved the way for a new era of RNA therapeutics. RNA Interference (RNAi) based approach using small interfering RNA may complement clinical management of the COVID-19. RNA Interference approach will primarily work by restricting the synthesis of the proteins required for viral replication, thereby hampering viral cellular entry and trafficking by targeting host as well as protein factors. Despite promising benefits, the stability of small interfering RNA in the physiological environment is of grave concern as well as site-directed targeted delivery and evasion of the immune system require immediate attention. In this regard, nanotechnology offers viable solutions for these challenges. The review highlights the potential of small interfering RNAs targeted toward specific regions of the viral genome and the features of nanoformulations necessary for the entrapment and delivery of small interfering RNAs. In silico design of small interfering RNA for different variants of SARS-CoV-2 has been discussed. Various nanoparticles as promising carriers of small interfering RNAs along with their salient properties, including surface functionalization, are summarized. This review will help tackle the real-world challenges encountered by the in vivo delivery of small interfering RNAs, ensuring a safe, stable, and readily available drug candidate for efficient management of SARS-CoV-2 in the future.
ABSTRACT
Magnetic hyperthermia is emerging as a promising alternative to the currently available cancer treatment modalities. Superparamagnetic iron-oxide nanoparticles (SPIONs) are extensively studied functional nanomaterials for biomedical applications, owing to their tunable physio-chemical properties and magnetic properties. Out of various ferrite classes, spinel and inverse-spinel ferrites are widely used but are affected by particle size distribution, particle shape, particle-particle interaction, geometry, and crystallinity. Notably, their heating ability makes them suitable candidates for heat-mediated cancer cell ablation or hyperthermia therapy. Exposing SPIONs to an externally applied magnetic field of appropriate frequency and intensity causes them to release heat to ablate cancer cells. Majorly, three heating mechanisms are exhibited by magnetic nanomaterials: Nèel relaxation, Brownian relaxation, and hysteresis losses. In SPIONs, Nèel and Brownian relaxations dominate, whereas hysteric losses are negligible. These nanomaterials possess high magnetization values capable of generating heat to ablate cancer cells. Furthermore, surface functionalization of these materials imparts the ability to selectively target cancer cells and deliver cargo to the affected area sparing the normal body cells. The surface of nanoparticles can be functionalized with various physical, chemical, and biological coatings. Moreover, hyperthermia can be applied in combination with other cancer treatment modalities in order to enhance the efficiency of treatment.
ABSTRACT
The growth-associated metabolites are produced during the exponential phase; however, this phase terminates due to substrate depletion or product inhibition. In the present study, a semicontinuous mode with a fill-and-draw strategy was applied to extend the exponential phase of the biosurfactant production to overcome the product inhibition and in turn, enhance the yield. Bioreactor studies were performed in batch mode, followed by the semicontinuous operation. A potential biosurfactant producer Bacillus subtilis RSL2 was used in this study at the previously optimized conditions of pH 6.6, temperature 41 °C and 5% (w/v) of molasses. A better mass transfer was achieved in the bioreactor as compared to the shake flask study. In the batch bioreactor study, 90% of sugar was utilized with simultaneous 13.7 g L-1 of biosurfactant production. The sugar utilization was further improved to > 98% in the case of semicontinuous operation employing a fill-and-draw strategy. The exponential phase got extended up to 18 days and a total of 13 L of media was fed in the semicontinuous operation of 21 days as compared to 1.5 L of working volume in the batch reactor. The biosurfactant yield was enhanced by 1.5 folds and was found to be 0.97 g g-1. The produced biosurfactant was identified as a lipopeptide. The interfacial properties of the biosurfactant along with colloidal and thermal stability have been investigated. The critical micelle concentration of the produced biosurfactant was 70 mg L-1. The present study highlighted the efficient utilization of molasses for the production of biosurfactant, an alternative metabolite, in a semicontinuous mode of bioreactor.
Subject(s)
Bacillus subtilis , Molasses , Bacillus subtilis/metabolism , Bioreactors , Micelles , Surface-Active Agents/chemistryABSTRACT
RNAi (RNA interference)-based technology is emerging as a versatile tool which has been widely utilized in the treatment of various diseases. siRNA can alter gene expression by binding to the target mRNA and thereby inhibiting its translation. This remarkable potential of siRNA makes it a useful candidate, and it has been successively used in the treatment of diseases, including cancer. However, certain properties of siRNA such as its large size and susceptibility to degradation by RNases are major drawbacks of using this technology at the broader scale. To overcome these challenges, there is a requirement for versatile tools for safe and efficient delivery of siRNA to its target site. Lipid nanoparticles (LNPs) have been extensively explored to this end, and this paper reviews different types of LNPs, namely liposomes, solid lipid NPs, nanostructured lipid carriers, and nanoemulsions, to highlight this delivery mode. The materials and methods of preparation of the LNPs have been described here, and pertinent physicochemical properties such as particle size, surface charge, surface modifications, and PEGylation in enhancing the delivery performance (stability and specificity) have been summarized. We have discussed in detail various challenges facing LNPs and various strategies to overcome biological barriers to undertake the safe delivery of siRNA to a target site. We additionally highlighted representative therapeutic applications of LNP formulations with siRNA that may offer unique therapeutic benefits in such wide areas as acute myeloid leukaemia, breast cancer, liver disease, hepatitis B and COVID-19 as recent examples.
ABSTRACT
The spreading of coronavirus from contacting surfaces and aerosols created a pandemic around the world. To prevent the transmission of SARS-CoV-2 virus and other contagious microbes, disinfection of contacting surfaces is necessary. In this study, a disinfection box equipped with infrared (IR) radiation heating and ultraviolet-C (UV-C) radiation is designed and tested for its disinfection ability against pathogenic bacteria and SARS-CoV-2 spike protein. The killing of a Gram-positive, namely, S. aureus and a Gram-negative namely, S. typhi bacteria was studied followed by the inactivation of the spike protein. The experimental parameters were optimized using a statistical tool. For the broad-spectrum antibacterial activity, the optimum condition was holding at 65.61 °C for 13.54 min. The killing of the bacterial pathogen occurred via rupturing the cell walls as depicted by electron microscopy. Further, the unfolding of SARS-CoV-2 spike protein and RNase A was studied under IR and UV-C irradiations at the aforesaid optimized condition. The unfolding of both the proteins was confirmed by changes in the secondary structure, particularly an increase in ß-sheets and a decrease in α-helixes. Remarkably, the higher penetration depth of IR waves up to subcutaneous tissue resulted in lower optimum disinfection temperature, <70 °C in vogue. Thus, the combined UV-C and IR radiation is effective in killing the pathogenic bacteria and denaturing the glycoproteins.
Subject(s)
COVID-19 , Spike Glycoprotein, Coronavirus , Humans , Disinfection/methods , SARS-CoV-2 , Staphylococcus aureus , Respiratory Aerosols and Droplets , Ultraviolet RaysABSTRACT
Crude oil bioremediation requires a correct selection of potential biodegraders to address the hazard. The present study investigates biodegradation kinetics of single aliphatic (Hexadecane, HEX), aromatic (Phenanthrene, PHE), and binary mixture (HEX + PHE) as co-contaminants by axenic cultures of A. fabrum SLAJ 731, B. subtilis RSL2 and P. aeruginosa P7815 and their consortium. A proposed integrated kinetic model combining first-order exponential decay and the Monod equation is well-fitted to degradation data. Maximum degradations of both the substrates were observed for microcosm, indicating synergistic effects of selected strains. The degradation rate indicated parallel utilization of HEX while serial utilization of PHE by selected strains. Maximum HEX and PHE degradations of 92.4 and 88.7 % were achieved by microconsortium, which increased to 97.2 and 91.9 % for the binary mixture. The biodegradation efficiencies of HEX and PHE were linearly correlated with Alkane hydroxylase and Catechol-2,3-dioxygenase activities, respectively.
Subject(s)
Phenanthrenes , Alkanes/metabolism , Bacteria/metabolism , Biodegradation, Environmental , Kinetics , Phenanthrenes/metabolismABSTRACT
The aggregation of therapeutic proteins is potentially encountered during various steps such as bioprocessing, formulation, storage, transportation and administration. The aggregation results in irreversible drug loss and also leads to an increase in the risk of immunogenicity. The aggregated proteins have also been associated with various protein deposition diseases like amyloidosis. Various physicochemical factors like pH, temperature, salt concentrations, ionic strength, shear and surface affect the stability of proteins. Interestingly, therapeutic proteins simultaneously experience these physical, chemical and mechanical stresses during upstream, downstream and storage processes. The above physicochemical factors are reported to induce the unfolding and aggregation of proteins. The mechanistic insights of this complex aggregation behavior may allow devising strategies to limit/restrict this unwanted phenomenon. This review intends to undertake systematic descriptions of the key physicochemical factors in upstream and downstream bioprocesses and correlating their implications with the unfolding and aggregation of therapeutic proteins. The present review highlights the impacts of environmental, chemical and mechanical factors of the bioprocessing on the stability/aggregation of therapeutic proteins. The present review offers insight into this important phenomenon, which will be helpful for real-world challenges in the bioprocess and bio-therapeutic industries.
Subject(s)
Antibodies, Monoclonal , Protein Stability , TemperatureABSTRACT
Biosurfactants are non-toxic, surface-active biomolecules capable of reducing surface tension (ST) and emulsifying interface at a comparably lower concentration than commercial surfactants. Yet, poor yield, costlier substrates, and complex cultivation processes limit their commercial applications. This study focuses on producing biosurfactants by Pseudomonas aeruginosa P7815 in batch and fed-batch bioreactor systems using waste cooking oil (WCO) as the sole carbon source. The batch study showed a 92% of WCO biodegradation ability of P. aeruginosa producing 11 g L-1 of biosurfactant. To enhance this biosurfactant production, a fed-batch oil feeding strategy was opted to extend the stationary phase of the bacterium and minimize the effects of substrate deprivation. An enhanced biosurfactant production of 16 g L-1 (i.e. 1.5 times of batch study) was achieved at a feed rate of 5.7 g L-1d-1 with almost 94% of WCO biodegradation activity. The biosurfactant was characterized as rhamnolipid using Fourier transform infrared spectroscopy (FTIR), and its interfacial characterization showed ST reduction to 29 ± 1 mN m-1 and effective emulsification stability at pH value of 4, temperature up to 40 °C and salinity up to 40 g L-1. The biosurfactant exhibited antibacterial activity with minimum inhibitory concentration (MIC) values of 100 µg mL-1 and 150 µg mL-1 for pathogenic E. hirae and E. coli, respectively. These findings suggest that biodegradation of WCO by P. aeruginosa in a fed-batch cultivation strategy is a potential alternative for the economical production of biosurfactants, which can be further explored for biomedical, cosmetics, and oil washing/recovery applications.
Subject(s)
Escherichia coli , Pseudomonas aeruginosa , Biodegradation, Environmental , Bioreactors , Cooking , Escherichia coli/metabolism , Glycolipids , Pseudomonas aeruginosa/metabolism , Surface-Active Agents/chemistryABSTRACT
Over the decades the presence of aquatic weeds has caused immense biodiversity loss to the ecosystem. The use of herbicides has arisen emergence of herbicide-resistant weeds and loss of inherent flora and fauna due to the recalcitrant nature of the chemicals used. Hence, there is a need to use nontoxic, ecosustainable, low-cost, and efficient biological molecules that are analogous to chemical herbicides. Various plants, bacteria, fungi as well a few viruses are reported to secrete allelopathic biomolecules that inhibit the growth and development of weeds. However, majorly fungal pathogens and their metabolites are found to be effective biocontrol agents for the water hyacinth. The present review puts forward major findings and interventions in the biological control of the weed, water hyacinth. The biosynthesis, mechanism of action and factors regulating the activity of bioherbicides are discussed. In addition, the issues associated with the in situ application of these bioherbicides are also conferred focusing on the available mode of applications and formulation used. The major factors include the type and concentration of allelopathic biomolecules, age, type, and morphology of targeted weed, formulation type, mode of application and other physiological and environmental factors. Among various modes for the application of bioherbicides, emulsions are found to be most effective for the control of water hyacinth. Most of the toxicity studies indicated no toxicity of this fungal pathogen to other ecological plant species except water hyacinth. Yet, in-depth investigations are needed of these allelochemicals and toxins before field applications. Overall, lab-scale studies have shown promising results and highlighted a few potential fungi that need to be further explored for optimizing their bioherbicidal activity.
Subject(s)
Eichhornia , Ecosystem , Fungi , Plant Weeds/metabolism , Prospective StudiesABSTRACT
The article investigates electrically active ceramic composite of [Formula: see text] (HAP) and [Formula: see text] (BST) for biomedical applications. The study is a systematic blend of the materials science aspect of composites with a special focus on the dielectric and biological properties and their relationships. The article emphasized primarily extracting the dielectric constant ([Formula: see text] of the specimens (that lay in the range of 3-65) and related them to microstructural properties like the grain size and at.% of BST. A broad outlook on the importance of [Formula: see text] in determining the suitability of bioceramics for clinical applications is presented. Bioactivity analysis of the specimens led to probing the surface charges (that were negative), and it was found crucial to the growth of dense apatite layers. Furthermore, the cytocompatibility of the specimens displayed cell viability above 100% for Day 1, which increased substantially for Day 3. To reveal other biological properties of the composites, protein adsorption studies using bovine serum albumin (BSA) and fetal bovine serum (FBS) was carried out. Electrostatic interactions govern the adsorption, and the mathematical dependence on surface charges is linear. The protein adsorption is also linearly correlated with the [Formula: see text], intrinsic to the biomaterials. We delve deeper into protein-biomaterials interactions by considering the evolution of the secondary structure of BSA adsorbed into the specimens. Based on the investigations, 20 at.% HAP-80 at.% BST (20H-80B) was established as a suitable composite comprising the desired features of HAP and BST. Such explorations of electrical and biological properties are interesting for modulating the behavior of bioceramic composites. The results project the suitability of 20H-80B for designing electrically active smart scaffolds for the proposed biomedical applications and are expected to incite further clinical trials.
Subject(s)
Biocompatible Materials/chemistry , Ceramics/chemistry , Tissue Engineering , Adsorption , Serum Albumin, Bovine/chemistryABSTRACT
Melanoidins are classified as hazardous colouring and polluting biopolymers, which are generated in very large amounts in molasses-based distillery effluent. In this study, melanoidin was removed through adsorption using amine surface-modified Phyllanthus emblica leaf powder (PELP) as a low-cost natural adsorbent. The amine-modified adsorbents were prepared by forming self-assembled monolayers (SAMs). The pzc of melanoidin and anime-modified PELP were found to be 6.9 and 3.8, respectively. RSM-CCD was used to optimize the environmental conditions considering adsorbent doses (0.2-2 % w/v), pH (3-11) and temperature (25-55 °C). A complete decolourization of melanoidin (98.50 ± 1 %) was observed at the optimized conditions (44.0 °C, pH = 5.93 and dose = 1.34 % w/v) along with 93.4 ± 0.2 % of COD reduction. The surface modification enhanced the maximum adsorption capacity to 616.2 mg g-1 i.e. 2.5 folds. The modified adsorbent also resulted in colour removal and COD reduction as 91 ± 3 and 84 ± 2 %, respectively from a real spentwash sample.
Subject(s)
Phyllanthus emblica , Water Pollutants, Chemical , Adsorption , Amines , Plant Leaves , Polymers , PowdersABSTRACT
SARS-CoV-2 virus and other pathogenic microbes are transmitted to the environment through contacting surfaces, which need to be sterilized for the prevention of COVID-19 and related diseases. In this study, a prototype of a cost-effective sterilization box is developed to disinfect small items. The box utilizes ultra violet (UV) radiation with heat. For performance assessment, two studies were performed. First, IgG (glycoprotein, a model protein similar to that of spike glycoprotein of SARS-COV-2) was incubated under UV and heat sterilization. An incubation with UV at 70 °C for 15 min was found to be effective in unfolding and aggregation of the protein. At optimized condition, the hydrodynamic size of the protein increased to ~171 nm from ~5 nm of the native protein. Similarly, the OD280 values also increased from 0.17 to 0.78 indicating the exposure of more aromatic moieties and unfolding of the protein. The unfolding and aggregation of the protein were further confirmed by the intrinsic fluorescence measurement and FTIR studies, showing a 70% increase in the ß-sheets and a 22% decrease in the α-helixes of the protein. The designed box was effective in damaging the protein's native structure indicating the effective inactivation of the SARS-COV-2. Furthermore, the incubation at 70 °C for 15 min inside the chamber resulted in 100% antibacterial efficacy for the clinically relevant E.coli bacteria as well as for bacteria collected from daily use items. It is the first detailed performance study on the efficacy of using UV irradiation and heat together for disinfection from virus and bacteria.
Subject(s)
COVID-19 , Ultraviolet Rays , Hot Temperature , Humans , SARS-CoV-2 , Virus InactivationABSTRACT
Protein aggregation is induced by various environmental or external factors and associated with various neurodegenerative diseases. Among various external factors, shear stress is inevitable for both in vivo and in vitro applications of proteins. In this study, Aß (1-40) peptide, a derivative of the amyloid precursor protein, was subjected to constant (300, 500, 700 s-1) and varying (ramp) shear in a parallel plate geometry to explore the implications of shear in terms of macro (viscosity) and micro (secondary structure, morphology) characteristics. Aß (1-40) solution followed a shear thickening flow behaviour with performance index value 'n' of 2.12. The fibrillation process resulting from the shear force was evaluated in terms of dissipation energy, which was found to exceed the free energy of unfolding. This resulted in the formation of ß-sheet rich structures, which were confirmed by CD and FTIR analyses and enhanced Th-T fluorescence. The apparent rate of aggregation (k) was found to increase with the shear rate, and inversely related to the solution viscosity. The maximum k value was 0.21 ± 0.3 min-1 at 700 s-1. The molecular weights of aggregates were determined using gel filtration, which were proportionally related to the solution viscosity. The average molecular weights were estimated to be 70, 62 and 52 KDa for samples sheared at 300, 500 and 700 s-1, respectively. The present study has deciphered the interplay of viscosity, a fluid property, with the aggregation process and its corresponding change in the secondary structures of the peptide. These findings provide useful insights for understanding various proteopathies under shear force.Communicated by Ramaswamy H. Sarma.