Raman Spectroscopy to Monitor Post-Translational Modifications and Degradation in Monoclonal Antibody Therapeutics

Aggregation of therapeutic monoclonal antibodies due to thermal and air/liquid interfacial agitation stress: Occurrence, stability assessment strategies, aggregation mechanism, influencing factors, and ways to enhance stability

Therapeutic proteins, such as monoclonal antibodies (mAbs) are known to undergo stability related issues during various stages of product life cycle resulting in the formation of aggregates and fragments. Aggregates of mAb might result in reduced therapeutic activity and could cause various adverse immunogenic responses. Sample containing mAb undergo aggregation due to various types of stress factors, and there is always a continuous interest among researchers and manufacturers to determine the effect of different factors on the stability of mAb. Thermal stress and air/liquid interfacial agitation stress are among two of the common stress factors to which samples containing mAb are exposed to during various stages. Initial part of this review articles aims to provide a generalized understanding of aggregation of mAb such as size ranges of aggregates, aggregate types, stress factors, analytical techniques, permissible aggregate limits, and stability assessment methods. This article further aims to explain different aspects associated with aggregation of mAb in liquid samples due to thermal and air/liquid interfacial agitation stress. Under each stress category, the occurrence of stress during product life cycle, type of aggregates formed, mechanism of aggregation, strategies used by various researchers to expose mAb containing samples to stress, different factors affecting aggregation, fate of aggregates in human body fluids, and strategies used to enhance mAb stability has been explained in detail. The authors hope that this article provides a detailed understanding about stability of mAb due to thermal and air/liquid interfacial stress with relevance to product life cycle from manufacturing to administration into patients.

Simple and fast one-step FRET assay of therapeutic mAb bevacizumab using anti-idiotype DNA aptamer for process analytical technology

We developed an aptamer-based fluorescence resonance energy transfer (FRET) assay capable of recognizing therapeutic monoclonal antibody bevacizumab and rapidly quantifying its concentration with just one mixing step. In this assay, two fluorescent dyes (fluorescein and tetramethylrhodamine) labeled aptamers bind to two Fab regions on bevacizumab, and FRET fluorescence is observed when both dyes come into close proximity. We optimized this assay in three different formats, catering to a wide range of analytical needs. When applied to hybridoma culture samples in practical settings, this assay exhibited a signal response that was concentration-dependent, falling within the range of 50-2000 μg/mL. The coefficients of determination (r2) ranged from 0.998 to 0.999, and bias and precision results were within ±24.0 % and 20.3 %, respectively. Additionally, during thermal and UV stress testing, this assay demonstrated the ability to detect denatured samples in a manner comparable to conventional Size Exclusion Chromatography. Notably, it offers the added advantage of detecting decreases in binding activity without changes in molecular weight. In contrast to many existing process analytical technology tools, this assay not only identifies bevacizumab but also directly measures the quality attributes related to mAb efficacy, such as the binding activity. As a result, this assay holds great potential as a valuable platform for providing highly reliable quality attribute information in real-time. We consider this will make a significant contribution to the worldwide distribution of high-quality therapeutic mAbs in various aspects of antibody manufacturing, including production monitoring, quality control, commercial lot release, and stability testing.

In-line fiber optical sensor for detection of IgG aggregates in affinity chromatography

Therapeutic monoclonal antibodies (mAbs) are critical for treatment of a wide range of diseases. Immunoglobulin G (IgG) is the most predominant form of mAb but is prone to aggregation during production. Detection and removal of IgG aggregates are time-consuming and laborious. Chromatography is central for purification of biopharmaceuticals in general and essential in the production of mAbs. Protein purification systems are usually equipped with detectors for monitoring pH, UV absorbance, and conductivity, to facilitate optimization and control of the purification process. However, specific in-line detection of the target products and contaminating species, such as aggregates, is currently not possible using convectional techniques. Here we show a novel fiber optical in-line sensor, based on localized surface plasmon resonance (LSPR), for specific detection of IgG and IgG aggregates during affinity chromatography. A flow cell with a Protein A sensor chip was connected to the outlet of the affinity column connected to three different chromatography systems operating at lab scale to pilot scale. Samples containing various IgG concentrations and aggregate contents were analyzed in-line during purification on a Protein A column using both pH gradient and isocratic elution. Because of avidity effects, IgG aggregates showed slower dissociation kinetics than monomers after binding to the sensor chips. Possibilities to detect aggregate concentrations below 1 % and difference in aggregate content smaller than 0.3 % between samples were demonstrated. In-line detection of aggregates can circumvent time-consuming off-line analysis and facilitate automation and process intensification.

A rapid method to monitor structural perturbations of high-concentrated therapeutic antibody solutions using Intrinsic Tryptophan Fluorescence Emission spectroscopy

Drug product development of therapeutic antibody formulations is still dictated by the risk of protein particle formation during processing or storage, which can lead to loss of potency and potential immunogenic reactions. Since structural perturbations are the main driver for irreversible protein aggregation, the conformational integrity of antibodies should be closely monitored. The present study evaluated the applicability of a plate reader-based high throughput method for Intrinsic Tryptophan Fluorescence Emission (ITFE) spectroscopy to detect protein aggregation due to protein unfolding in high-concentrated therapeutic antibody samples. The impact of fluorophore concentration on the ITFE signal in microplate readers was investigated by analysis of dilution series of two therapeutic antibodies and pure tryptophan. At low antibody concentrations (< 5 mg/mL, equivalent to 0.8 mM tryptophan), the low inner filter effect suggests a quasi-linear relationship between antibody concentration and ITFE intensity. In contrast, the constant ITFE intensity at high protein concentrations (> 40 mg/mL, equivalent to 6.1 mM tryptophan) indicate that ITFE spectroscopy measurements of IgG1 antibodies are feasible in therapeutically relevant concentrations (up to 223 mg/mL). Furthermore, the capability of the method to detect low levels of unfolding (around 1 %) was confirmed by limit of detection (LOD) determination with temperature-stressed antibody samples as degradation standards. Change of fluorescence intensity at the maximum (ΔIaM) was identified as sensitive descriptor for protein degradation, providing the lowest LOD values. The results demonstrate that ITFE spectroscopy performed in a microplate reader is a valuable tool for high-throughput monitoring of protein degradation in therapeutic antibody formulations.

Development of generic metabolic Raman calibration models using solution titration in aqueous phase and data augmentation for in-line cell culture analysis

This study presents a novel approach for developing generic metabolic Raman calibration models for in-line cell culture analysis using glucose and lactate stock solution titration in an aqueous phase and data augmentation techniques. First, a successful set-up of the titration method was achieved by adding glucose or lactate solution at several different constant rates into the aqueous phase of a bench-top bioreactor. Subsequently, the in-line glucose and lactate concentration were calculated and interpolated based on the rate of glucose and lactate addition, enabling data augmentation and enhancing the robustness of the metabolic calibration model. Nine different combinations of spectra pretreatment, wavenumber range selection, and number of latent variables were evaluated and optimized using aqueous titration data as training set and a historical cell culture data set as validation and prediction set. Finally, Raman spectroscopy data collected from 11 historical cell culture batches (spanning four culture modes and scales ranging from 3 to 200 L) were utilized to predict the corresponding glucose and lactate values. The results demonstrated a high prediction accuracy, with an average root mean square errors of prediction of 0.65 g/L for glucose, and 0.48 g/L for lactate. This innovative method establishes a generic metabolic calibration model, and its applicability can be extended to other metabolites, reducing the cost of deploying real-time cell culture monitoring using Raman spectroscopy in bioprocesses.

Use of Raman spectroscopy and PCA for quality evaluation and out-of-specification identification in biopharmaceutical products

Over the past three decades, there was a remarkable growth in the approval of antibody-based biopharmaceutical products. These molecules are notably susceptible to the stresses occurring during drug manufacturing, often leading to structural alterations. A key concern is thus the ability to detect and comprehend these alterations caused by processes, such as aggregation, fragmentation, oxidation levels, as well as the change in protein concentration throughout the process steps, potentially resulting in out-of-spec products. In the present study, Raman spectroscopy, coupled with Principal Component Analysis (PCA), has proven to be an excellent tool for characterizing protein-based products. Notably, it offers the advantages of being minimally invasive, rapid and relatively insensitive to water. Therefore, it was successfully employed to discriminate between various stresses impacting a monoclonal antibody (mAb). The molecule used in this study is a fully human IgG1 fusion protein. Thermal stress was induced by incubating the samples at 50 °C for one month, while oxidative stress was induced by introducing hydrogen peroxide. Additionally, dilutions were performed to explore a broader range of protein concentrations. Specific key bands were identified in the Raman spectra, which facilitated the PCA classification and allowed for their association with distinct changes in the secondary and tertiary structures of the protein. Notably, it was observed that signals corresponding to amino acids exhibited a decrease in intensity with increasing levels of thermal stress, while other alterations were noted in the amide bands. It was shown that changes in the range 2800-3000 cm-1 pertains to the dilution process, while specific peaks of C-H stretching were essential for the discrimination between the oxidative-stressed samples and the thermal and diluted counterparts. Furthermore, the model calibrated on the mAb demonstrated remarkable performance when used to evaluate a different product, e.g. a hormone.

Basic regulatory science behind drug substance and drug product specifications of monoclonal antibodies and other protein therapeutics

In this review, we focus on providing basics and examples for each component of the protein therapeutic specifications to interested pharmacists and biopharmaceutical scientists with a goal to strengthen understanding in regulatory science and compliance. Pharmaceutical specifications comprise a list of important quality attributes for testing, references to use for test procedures, and appropriate acceptance criteria for the tests, and they are set up to ensure that when a drug product is administered to a patient, its intended therapeutic benefits and safety can be rendered appropriately. Conformance of drug substance or drug product to the specifications is achieved by testing an article according to the listed tests and analytical methods and obtaining test results that meet the acceptance criteria. Quality attributes are chosen to be tested based on their quality risk, and consideration should be given to the merit of the analytical methods which are associated with the acceptance criteria of the specifications. Acceptance criteria are set forth primarily based on efficacy and safety profiles, with an increasing attention noted for patient-centric specifications. Discussed in this work are related guidelines that support the biopharmaceutical specification setting, how to set the acceptance criteria, and examples of the quality attributes and the analytical methods from 60 articles and 23 pharmacopeial monographs. Outlooks are also explored on process analytical technologies and other orthogonal tools which are on-trend in biopharmaceutical characterization and quality control.

Simultaneous prediction of 16 quality attributes during protein A chromatography using machine learning based Raman spectroscopy models

Several key technologies for advancing biopharmaceutical manufacturing depend on the successful implementation of process analytical technologies that can monitor multiple product quality attributes in a continuous in-line setting. Raman spectroscopy is an emerging technology in the biopharma industry that promises to fit this strategic need, yet its application is not widespread due to limited success for predicting a meaningful number of quality attributes. In this study, we addressed this very problem by demonstrating new capabilities for preprocessing Raman spectra using a series of Butterworth filters. The resulting increase in the number of spectral features is paired with a machine learning algorithm and laboratory automation hardware to drive the automated collection and training of a calibration model that allows for the prediction of 16 different product quality attributes in an in-line mode. The demonstrated ability to generate these Raman-based models for in-process product quality monitoring is the breakthrough to increase process understanding by delivering product quality data in a continuous manner. The implementation of this multiattribute in-line technology will create new workflows within process development, characterization, validation, and control.

Taurine, a Naturally Occurring Amino Acid, as a Physical Stability Enhancer of Different Monoclonal Antibodies

Degradation of therapeutic monoclonal antibodies (mAbs) is a major concern as it affects efficacy, shelf-life, and safety of the product. Taurine, a naturally occurring amino acid, is investigated in this study as a potential mAb stabilizer with an extensive analytical characterization to monitor product degradation. Forced degradation of trastuzumab biosimilar (mAb1)-containing samples by thermal stress for 30 min resulted in high-molecular-weight species by more than 65% in sample without taurine compared to the sample with taurine. Samples containing mAb1 without taurine also resulted in higher Z-average diameter, altered protein structure, higher hydrophobicity, and lower melting temperature compared to samples with taurine. The stabilizing effect of taurine was retained at different mAb and taurine concentrations, time, temperatures, and buffers, and at the presence of polysorbate 80 (PS80). Even the lowest taurine concentration (10 mM) considered in this study, which is in the range of taurine levels in amino acid injections, resulted in enhanced mAb stability. Taurine-containing samples resulted in 90% less hemolysis than samples containing PS80. Additionally, mAb in the presence of taurine showed enhanced stability upon subjecting to stress with light of 365 nm wavelength, combination of light and H2O2, and combination of Fe2+ and H2O2, as samples containing mAb without taurine resulted in increased degradation products by more than 50% compared to samples with taurine upon subjecting to these stresses for 60 min. In conclusion, the presence of taurine enhanced physical stability of mAb by preventing aggregate formation, and the industry can consider it as a new mAb stabilizer.

Automated calibration and in-line measurement of product quality during therapeutic monoclonal antibody purification using Raman spectroscopy

Current manufacturing and development processes for therapeutic monoclonal antibodies demand increasing volumes of analytical testing for both real-time process controls and high-throughput process development. The feasibility of using Raman spectroscopy as an in-line product quality measuring tool has been recently demonstrated and promises to relieve this analytical bottleneck. Here, we resolve time-consuming calibration process that requires fractionation and preparative experiments covering variations of product quality attributes (PQAs) by engineering an automation system capable of collecting Raman spectra on the order of hundreds of calibration points from two to three stock seed solutions differing in protein concentration and aggregate level using controlled mixing. We used this automated system to calibrate multi-PQA models that accurately measured product concentration and aggregation every 9.3 s using an in-line flow-cell. We demonstrate the application of a nonlinear calibration model for monitoring product quality in real-time during a biopharmaceutical purification process intended for clinical and commercial manufacturing. These results demonstrate potential feasibility to implement quality monitoring during GGMP manufacturing as well as to increase chemistry, manufacturing, and controls understanding during process development, ultimately leading to more robust and controlled manufacturing processes.

Challenges in scaling up AAV-based gene therapy manufacturing

Accelerating the scale up of adeno-associated virus (AAV) manufacture is highly desirable to meet the increased demand for gene therapies. However, the development of bioprocesses for AAV gene therapies remains time-consuming and challenging. The quality by design (QbD) approach ensures bioprocess designs that meet the desired product quality and safety profile. Rapid stress tests, developability screens, and scale-down technologies have the potential to streamline AAV product and manufacturing bioprocess development within the QbD framework. Here we review how their successful use for antibody manufacture development is translating to AAV, but also how this will depend critically on improved analytical methods and adaptation of the tools as more understanding is gained on the critical attributes of AAV required for successful therapy.

Instantaneous Inactivation of Herpes Simplex Virus by Silicon Nitride Bioceramics

Hydrolytic reactions taking place at the surface of a silicon nitride (Si3N4) bioceramic were found to induce instantaneous inactivation of Human herpesvirus 1 (HHV-1, also known as Herpes simplex virus 1 or HSV-1). Si3N4 is a non-oxide ceramic compound with strong antibacterial and antiviral properties that has been proven safe for human cells. HSV-1 is a double-stranded DNA virus that infects a variety of host tissues through a lytic and latent cycle. Real-time reverse transcription (RT)-polymerase chain reaction (PCR) tests of HSV-1 DNA after instantaneous contact with Si3N4 showed that ammonia and its nitrogen radical byproducts, produced upon Si3N4 hydrolysis, directly reacted with viral proteins and fragmented the virus DNA, irreversibly damaging its structure. A comparison carried out upon testing HSV-1 against ZrO2 particles under identical experimental conditions showed a significantly weaker (but not null) antiviral effect, which was attributed to oxygen radical influence. The results of this study extend the effectiveness of Si3N4's antiviral properties beyond their previously proven efficacy against a large variety of single-stranded enveloped and non-enveloped RNA viruses. Possible applications include the development of antiviral creams or gels and oral rinses to exploit an extremely efficient, localized, and instantaneous viral reduction by means of a safe and more effective alternative to conventional antiviral creams. Upon incorporating a minor fraction of micrometric Si3N4 particles into polymeric matrices, antiherpetic devices could be fabricated, which would effectively impede viral reactivation and enable high local effectiveness for extended periods of time.

Identification of monoclonal antibody drug substances using non-destructive Raman spectroscopy

Monoclonal antibodies provide highly specific and effective therapies for the treatment of chronic diseases. These protein-based therapeutics, or drug substances, are transported in single used plastic packaging to fill finish sites. According to good manufacturing practice guidelines, each drug substance needs to be identified before manufacturing of the drug product. However, considering their complex structure, it is challenging to correctly identify therapeutic proteins in an efficient manner. Common analytical techniques for therapeutic protein identification are SDS-gel electrophoresis, enzyme linked immunosorbent assays, high performance liquid chromatography and mass spectrometry-based assays. Although effective in correctly identifying the protein therapeutic, most of these techniques need extensive sample preparation and removal of samples from their containers. This step not only risks contamination but the sample taken for the identification is destroyed and cannot be re-used. Moreover, these techniques are often time consuming, sometimes taking several days to process. Here, we address these challenges by developing a rapid and non-destructive identification technique for monoclonal antibody-based drug substances. Raman spectroscopy in combination with chemometrics were used to identify three monoclonal antibody drug substances. This study explored the impact of laser exposure, time out of refrigerator and multiple freeze thaw cycles on the stability of monoclonal antibodies. and demonstrated the potential of using Raman spectroscopy for the identification of protein-based drug substances in the biopharmaceutical industry.

Imaged capillary isoelectric focusing associated with multivariate analysis: A powerful tool for quality control of therapeutic monoclonal antibodies

Monoclonal antibodies are increasingly used in cancer therapy. To guarantee the quality of these mAbs from compounding to patient administration, characterization methods are required (e.g. identity). In a clinical setting, these methods must be fast and straightforward. For this reason, we investigated the potential of image capillary isoelectric focusing (icIEF) combined with Principal Component Analysis (PCA) and Partial least squares-discriminant analysis (PLS-DA). icIEF profiles obtained from monoclonals antibodies (mAbs) analysis have been pre-processed and the data submitted to principal component analysis (PCA). This pre-processing method has been designed to avoid the impact of concentration and formulation. Analysis of four commercialized mAbs (Infliximab, Nivolumab, Pertuzumab, and Adalimumab) by icIEF-PCA led to the formation of four clusters corresponding to each mAb. Partial least squares-discriminant analysis (PLS-DA) applied to these data allowed us to build models to predict which monoclonal antibody is analyzed. The validation of this model was obtained from k-fold cross-validation and prediction tests. The selectivity and the specificity of the model performance parameters were assessed by the excellent classification obtained. In conclusion, we established that the combination of icIEF and chemometric approaches is a reliable approach for unambiguously identifying compounded therapeutic monoclonal antibodies (mAbs) before patient administration.

Atezolizumab-Conjugated Poly(lactic acid)/Poly(vinyl alcohol) Nanoparticles as Pharmaceutical Part Candidates for Radiopharmaceuticals

The necessity of new drugs for lung cancer therapy and imaging is increasing each day. The development of new drugs that are capable of reaching the tumor with specificity and selectivity is required. In this direction, the design of nanoparticles for tumor therapy represents an important alternative. The aim of this study was to develop, characterize, and evaluate target-specific atezolizumab-conjugated poly(lactic acid)/poly(vinyl alcohol) (PLA/PVA) nanoparticles as pharmaceutical fragment candidates for new radiopharmaceuticals. For this purpose, PLA/PVA nanoparticle formulations were prepared by the double emulsification/solvent evaporation method with a high-speed homogenizer. A special focus was oriented to the selection of a suitable method for modification of the nanoparticle surface with a monoclonal antibody. For this purpose, atezolizumab was bound to the nanoparticles during the preparation by solvent evaporation or either by adsorption or covalent binding. PLA/PVA/atezolizumab nanoparticles are characterized by dynamic light scattering, Raman spectroscopy, scanning electron microscopy, and atomic force microscopy. An in vitro assay was performed to evaluate the antibody binding efficiency, stability, and cytotoxicity [A549 (lung cancer cell) and L929 (healthy fibroblast cell)]. The results showed that a spherical nanoparticle with a size of 230.6 ± 1.768 nm and a ζ potential of -2.23 ± 0.55 mV was produced. Raman spectroscopy demonstrated that the monoclonal antibody was entrapped in the nanoparticle. The high antibody binding efficiency (80.58%) demonstrated the efficacy of the nanosystem. The cytotoxic assay demonstrated the safety of the nanoparticle in L929 and the effect on A549. In conclusion, PLA/PVA/atezolizumab nanoparticles can be used as drug delivery systems for lung cancer diagnosis and therapy.

[Latest Research Findings on Health Management Based on Saliva Testing]

Being one of the most important exocrine fluids of the human body, saliva can reflect the health status of the body. Soliva collection has various advantages--it is simple, painless, fast, and safe, and soliva can be collected multiple times a day. Therefore, it has been gradually applied in the exploration for biomarkers for disease detection, providing a basis for the monitoring of the course of diseases, medication monitoring, and efficacy evaluation. We should implement health management based on saliva testing, collect the medical data of the healthy and diseased individuals and monitor their whole life cycle health, perform clinical cohort study, aggregate the data on platforms for big data on health and medicine, manage and provide guidance for the health status of populations, pinpoint the high-risk factors for pathogenesis, and provide effective intervention, early warning, and assessment of the vital signs of individuals, thereby reinforcing health management of the whole life cycle and safeguarding people's health in an all-round way. In addition, it drives the development of the health industry and bears strategic significance for the promotion of national economic development. It is becoming a hot research topic promising great potential and impressive applicational prospects. Herein, we reviewed new techniques for clinical saliva testing and health management based on saliva testing.

Raman Fingerprints of the SARS-CoV-2 Delta Variant and Mechanisms of Its Instantaneous Inactivation by Silicon Nitride Bioceramics

Raman spectroscopy uncovered molecular scale markers of the viral structure of the SARS-CoV-2 Delta variant and related viral inactivation mechanisms at the biological interface with silicon nitride (Si3N4) bioceramics. A comparison of Raman spectra collected on the TY11-927 variant (lineage B.1.617.2; simply referred to as the Delta variant henceforth) with those of the JPN/TY/WK-521 variant (lineage B.1.617.1; referred to as the Kappa variant or simply as the Japanese isolate henceforth) revealed the occurrence of key mutations of the spike receptor together with profound structural differences in the molecular structure/symmetry of sulfur-containing amino acid and altered hydrophobic interactions of the tyrosine residue. Additionally, different vibrational fractions of RNA purines and pyrimidines and dissimilar protein secondary structures were also recorded. Despite mutations, hydrolytic reactions at the surface of silicon nitride (Si3N4) bioceramics induced instantaneous inactivation of the Delta variant at the same rate as that of the Kappa variant. Contact between virions and micrometric Si3N4 particles yielded post-translational deimination of arginine spike residues, methionine sulfoxidation, tyrosine nitration, and oxidation of RNA purines to form formamidopyrimidines. Si3N4 bioceramics proved to be a safe and effective inorganic compound for instantaneous environmental sanitation.

Extreme Point Sort Transformation Combined With a Long Short-Term Memory Network Algorithm for the Raman-Based Identification of Therapeutic Monoclonal Antibodies

Therapeutic monoclonal antibodies (mAbs) are a new generation of protein-based medicines that are usually expensive and thus represent a target for counterfeiters. In the present study, a method based on Raman spectroscopy that combined extreme point sort transformation with a long short-term memory (LSTM) network algorithm was presented for the identification of therapeutic mAbs. A total of 15 therapeutic mAbs were used in this study. An in-house Raman spectrum dataset for model training was created with 1,350 spectra. The characteristic region of the Raman spectrum was reduced in dimension and then transformed through an extreme point sort transformation into a sequence array, which was fitted for the LSTM network. The characteristic array was extracted from the sequence array using a well-trained LSTM network and then compared with standard spectra for identification. To demonstrate whether the present algorithm was better, ThermoFisher OMNIC 8.3 software (Thermo Fisher Scientific Inc., U.S.) with two matching modes was selected for comparison. Finally, the present method was successfully applied to identify 30 samples, including 15 therapeutic mAbs and 15 other injections. The characteristic region was selected from 100 to 1800 cm⁻¹ of the full spectrum. The optimized dimensional values were set from 35 to 53, and the threshold value range was from 0.97 to 0.99 for 15 therapeutic mAbs. The results of the robustness test indicated that the present method had good robustness against spectral peak drift, random noise and fluorescence interference from the measurement. The areas under the curve (AUC) values of the present method that were analysed on the full spectrum and analysed on the characteristic region by the OMNIC 8.3 software’s built-in method were 1.000, 0.678, and 0.613, respectively. The similarity scores for 15 therapeutic mAbs using OMNIC 8.3 software in all groups compared with that of the relative present algorithm group had extremely remarkable differences (p < 0.001). The results suggested that the extreme point sort transformation combined with the LSTM network algorithm enabled the characteristic extraction of the therapeutic mAb Raman spectrum. The present method is a proposed solution to rapidly identify therapeutic mAbs.

Synthesis of gold nanoparticles@reduced porous graphene-modified ITO electrode for spectroelectrochemical detection of SARS-CoV-2 spike protein

Here, we reported the synthesis of reduced porous graphene oxide (rPGO) decorated with gold nanoparticles (Au NPs) to modify the ITO electrode. Then we used this highly uniform Au NPs@rPGO modified ITO electrode as a surface-enhanced Raman spectroscopy-active surface and a working electrode. The uses of the Au nanoparticles and porous graphene enhance the Raman signals and the electrochemical conductivity. COVID-19 protein-based biosensor was developed based on immobilization of anti-COVID-19 antibodies onto the modified electrode and its uses as a probe for capturing the COVID-19 protein. The developed biosensor showed the capability of monitoring the COVID-19 protein within a concentration range from 100 nmol/L to 1 pmol/L with a limit of detection (LOD) of 75 fmol/L. Furthermore, COVID-19 protein was detected based on electrochemical techniques within a concentration range from 100 nmol/L to 500 fmol/L that showed a LOD of 39.5 fmol/L. Finally, three concentrations of COVID-19 protein spiked in human serum were investigated. Thus, the present sensor showed high efficiency towards the detection of COVID-19.

Multi-attribute Raman spectroscopy (MARS) for monitoring product quality attributes in formulated monoclonal antibody therapeutics

Rapid release of biopharmaceutical products enables a more efficient drug manufacturing process. Multi-attribute methods that target several product quality attributes (PQAs) at one time are an essential pillar of the rapid-release strategy. The novel, high-throughput, and nondestructive multi-attribute Raman spectroscopy (MARS) method combines Raman spectroscopy, design of experiments, and multivariate data analysis (MVDA). MARS allows the measurement of multiple PQAs for formulated protein therapeutics without sample preparation from a single spectroscopic scan. Variable importance in projection analysis is used to associate the chemical and spectral basis of targeted PQAs, which assists in model interpretation and selection. This study shows the feasibility of MARS for the measurement of both protein purity-related and formulation-related PQAs; measurements of protein concentration, osmolality, and some formulation additives were achieved by a generic multiproduct model for various protein products containing the same formulation components. MARS demonstrates the potential to be a powerful methodology to improve the efficiency of biopharmaceutical development and manufacturing, as it features fast turnaround time, good robustness, less human intervention, and potential for automation.

Photo-Oxidation of Therapeutic Protein Formulations: From Radical Formation to Analytical Techniques

UV and ambient light-induced modifications and related degradation of therapeutic proteins are observed during manufacturing and storage. Therefore, to ensure product quality, protein formulations need to be analyzed with respect to photo-degradation processes and eventually protected from light exposure. This task usually demands the application and combination of various analytical methods. This review addresses analytical aspects of investigating photo-oxidation products and related mediators such as reactive oxygen species generated via UV and ambient light with well-established and novel techniques.

The role of Raman spectroscopy in biopharmaceuticals from development to manufacturing

Biopharmaceuticals have revolutionized the field of medicine in the types of active ingredient molecules and treatable indications. Adoption of Quality by Design and Process Analytical Technology (PAT) frameworks has helped the biopharmaceutical field to realize consistent product quality, process intensification, and real-time control. As part of the PAT strategy, Raman spectroscopy offers many benefits and is used successfully in bioprocessing from single-cell analysis to cGMP process control. Since first introduced in 2011 for industrial bioprocessing applications, Raman has become a first-choice PAT for monitoring and controlling upstream bioprocesses because it facilitates advanced process control and enables consistent process quality. This paper will discuss new frontiers in extending these successes in upstream from scale-down to commercial manufacturing. New reports concerning the use of Raman spectroscopy in the basic science of single cells and downstream process monitoring illustrate industrial recognition of Raman’s value throughout a biopharmaceutical product’s lifecycle. Finally, we draw upon a nearly 90-year history in biological Raman spectroscopy to provide the basis for laboratory and in-line measurements of protein quality, including higher-order structure and composition modifications, to support formulation development.

Mechanisms of instantaneous inactivation of SARS-CoV-2 by silicon nitride bioceramic

The hydrolytic processes occurring at the surface of silicon nitride (Si3N4) bioceramic have been indicated as a powerful pathway to instantaneous inactivation of SARS-CoV-2 virus. However, the virus inactivation mechanisms promoted by Si3N4 remain yet to be elucidated. In this study, we provide evidence of the instantaneous damage incurred on the SARS-CoV-2 virus upon contact with Si3N4. We also emphasize the safety characteristics of Si3N4 for mammalian cells. Contact between the virions and micrometric Si3N4 particles immediately targeted a variety of viral molecules by inducing post-translational oxidative modifications of S-containing amino acids, nitration of the tyrosine residue in the spike receptor binding domain, and oxidation of RNA purines to form formamidopyrimidine. This structural damage in turn led to a reshuffling of the protein secondary structure. These clear fingerprints of viral structure modifications were linked to inhibition of viral functionality and infectivity. This study validates the notion that Si3N4 bioceramic is a safe and effective antiviral compound; and a primary antiviral candidate to replace the toxic and allergenic compounds presently used in contact with the human body and in long-term environmental sanitation.

Electrochemical Microbiosensor for Detecting COVID-19 in a Patient Sample Based on Gold Microcuboids Pattern

As continues increasing the COVID-19 infections, there is an urgent need for developing fast, simple, selective, and accurate COVID-19 biosensors. A highly uniform gold (Au) microcuboid pattern was used as a microelectrode that allowed monitoring a small analyte. The electrochemical biosensor was used to monitor the COVID-19 S protein within a concentration range from 100 to 5 pmol L⁻¹; it showed a lower detection limit of 276 fmol L⁻¹. Finally, the developed COVID-19 sensor was used to detect a positive sample from a human patient obtained through a nasal swab; the results were confirmed using the PCR technique. The results showed that the SWV technique showed high sensitivity towards detecting COVID-19 and good efficiency for detecting COVID-19 in a positive human sample.

Transcutaneous penetration of a single-chain variable fragment (scFv) compared to a full-size antibody: potential tool for atopic dermatitis (AD) treatment

Currently, several biologics are used for the treatment of cutaneous pathologies such as atopic dermatitis (AD), psoriasis or skin cancers. The main administration routes are subcutaneous and intravenous injections. However, little is known about antibody penetration through the skin. The aim was to study the transcutaneous penetration of a reduced-size antibody as a single-chain variable fragment (scFv) compared to a whole antibody (Ab) and to determine its capacity to neutralize an inflammatory cytokine involved in AD such as human interleukin-4 (hIL-4). Transcutaneous penetration was evaluated by ex vivo studies on tape-stripped pig ear skin. ScFv and Ab visualization through the skin was measured by Raman microspectroscopy. In addition, hIL-4 neutralization was studied in vitro using HEK-Blue™ IL-4/IL-13 cells and normal human keratinocytes (NHKs). After 24 h of application, analysis by Raman microspectroscopy showed that scFv penetrated into the upper dermis while Ab remained on the stratum corneum. In addition, the anti-hIL4 scFv showed very efficient and dose-dependent hIL-4 neutralization. Thus, scFv penetrates through to the upper papillary dermis while Ab mostly remains on the surface, the anti-hIL4 scFv also neutralizes its target effectively suggesting its potential use as topical therapy for AD.

Developments and opportunities in continuous biopharmaceutical manufacturing

Today's biologics manufacturing practices incur high costs to the drug makers, which can contribute to high prices for patients. Timely investment in the development and implementation of continuous biomanufacturing can increase the production of consistent-quality drugs at a lower cost and a faster pace, to meet growing demand. Efficient use of equipment, manufacturing footprint, and labor also offer the potential to improve drug accessibility. Although technological efforts enabling continuous biomanufacturing have commenced, challenges remain in the integration, monitoring, and control of traditionally segmented unit operations. Here, we discuss recent developments supporting the implementation of continuous biomanufacturing, along with their benefits.

Understanding the discrimination and quantification of monoclonal antibodies preparations using Raman spectroscopy

The use of Raman spectroscopy for analytical quality control of anticancer drug preparations in clinical pharmaceutical dispensing units is increasing in popularity, notably supported by commercially available, purpose designed instruments. Although not legislatively compulsory, analytical methods are frequently used post-preparation to verify the accuracy of a preparation in terms of identity and quantity of the drug in solution. However, while the rapid, cost effective and label free analysis achieved with Raman spectroscopy is appealing, it is important to understand the molecular origin of the spectral contributions collected from the solution of actives and excipients, to evaluate the strength and limitation for the technique, which can be used to identify and quantify either the prescribed commercial formulation, and/or the active drug itself, in personalised solutions. In the current study, four commercial formulations, Erbitux®, Truxima®, Ontruzant® and Avastin® of monoclonal antibodies (mAbs), corresponding respectively to cetuximab, rituximab, trastuzumab and bevacizumab have been used to highlight the key role of excipients in discrimination and quantification of the formulations. It is demonstrated that protein based anticancer drugs such as mAbs have a relatively weak Raman response, while excipients such as glycine, trehalose or histidine contribute significantly to the spectra. Multivariate analysis (partial least square regression and partial least square discriminant analysis) further demonstrates that the signatures of the mAbs themselves are not prominent in mathematical models and that those of the excipients are solely responsible for the differentiation of formulation and accurate determination of concentrations. While Raman spectroscopy can successfully validate the conformity of mAbs intravenous infusion solutions, the basis for the analysis should be considered, and special caution should be given to excipient compositions in commercial formulations to ensure reliability and reproducibility of the analysis.